One of the crucial directions in the pursuit of high-energy-density lithium batteries involves pairing Ni-rich cathodes with lithium metal anodes (LMAs). However, battery systems with high energy density often suffer from issues such as poor phase structure stability and inadequate interface compatibility. These problems are exacerbated under the actual operating conditions with high cut-off voltages and wide temperature ranges. Interface degradation, in such cases, accelerates the destruction of phase structure, leading to rapid performance deterioration of electrode materials. Compared to methods like ion doping and surface coating, an approach centered around electrolyte-induced interface reconstruction modification through solvent-lithium salt optimization or functional additives shows promise. This approach allows for simultaneous electrochemical cyclic modification of both high-energy-density cathode and anode materials, and it can be easily integrated into large-scale industrial production. Ester-based electrolytes, while possessing greater voltage stability compared to ether-based electrolytes, still exhibit side reactions at the interface between high Ni-content cathodes and the electrolyte, as well as between Li metal anodes and the electrolyte. In the absence of effective cathode-electrolyte interface (CEI) and solid-electrolyte interface (SEI) protection, persistent side reactions occur, ultimately leading to electrode failure. To address these challenges and simultaneously enhance electrode/electrolyte interface compatibility while regulating electrolyte solvation structure, functional additives are employed to modify the electrochemical behavior of the high-energy-density battery interface. Traditional ether electrolytes often employ lithium hexafluorophosphate (LiPF₆) as the primary salt. However, LiPF₆ suffers from poor thermal stability. Its decomposition or hydrolysis generates hydrogen fluoride (HF), which corrodes the cathode. Moreover, LiPF₆ decomposition releases phosphorus pentafluoride (PF₅), triggering the ring-opening of ethylene carbonate (EC), leading to electrolyte failure. PF₅ can also react with water to produce acidic compounds, further deteriorating battery performance. The extraction of Li⁺ ions in the cathode reduces oxygen binding energy, facilitating the release of lattice oxygen. This can lead to side reactions between reactive oxygen species and the electrolyte, increasing interface impedance. To tackle these issues, choosing electrolyte additives with diverse functions can expand the potential of electrolytes. By leveraging various functional electrolyte additives, it becomes possible to inhibit irreversible structural transformations in the cathode, prevent O₂/CO₂ precipitation, suppress interface side reactions, and facilitate the removal of acid-water impurities. This comprehensive study delves into the impact of different functional electrolyte additives on interface film reconstruction, interfacial adsorption stability, synergy on high-energy-density anode interface, and acid-water impurity removal in Ni-rich cathode and anode materials. The research opens up new avenues for the identification and design of specific functionalized additives, paving the way for achieving stable cycling in high-energy-density Ni-rich lithium batteries.

Hydrogen peroxide (H₂O₂) is an environmentally friendly oxidant that has been widely used in water treatment, medical disinfection, chemical synthesis, and other industrial applications. However, traditional methods used to produce H₂O₂ consume significant amounts of energy and generate hazardous by-products, which limit their scope. On-site and on-demand electrocatalytic two-electron water oxidation chemistry is an attractive option for directly producing H₂O₂ from water; it also avoids the hazardous anthraquinone method, has fewer transportation costs and risks, and is integratable with renewable electricity. Despite these advantages, the two-electron water oxidation reaction (2e^– WOR) still suffers from poor selectivity and activity due to a lack of mechanistic, material-design, and reactor-engineering understanding. This study summarizes recent advances in H₂O₂ electrosynthesis technology using the 2e^– WOR. The catalytic 2e^– WOR mechanism is first introduced with a focus on selectivity, activity, and stability. This reaction involves the electrocatalytic oxidation of water to produce H₂O₂, which can be further oxidized to O₂. Selectivity is influenced by a variety of factors, including the electrocatalyst, pH, and electrolyte. Various quantitative H₂O₂ methods are discussed along with in situ characterization studies into the 2e^– WOR aimed at better understanding the reaction process. Such methods include in situ Fourier-transform infrared spectroscopy and in situ Raman spectroscopy. Researchers are able to identify reaction intermediates and understand reaction mechanisms better using these techniques, thereby providing guidance for the design of more efficient electrocatalysts. In turn, various strategies for preparing high-performance electrocatalysts are summarized, including defect, doping, facet, and interfacial engineering methods. Mechanism-guided multiscale materials engineering can improve the activities and selectivities of electrocatalysts, thereby increasing H₂O₂ yields. In addition, device-level engineering, especially in relation to reactor and system innovations, is emphasized, which is important for improving reaction efficiency and reducing the cost of the 2e^– WOR. Finally, current challenges and future opportunities in the 2e^– WOR H₂O₂ electrosynthesis field are discussed. More effort directed at improving reaction selectivity, activity, and durability is required, along with exploring suitable application scenarios. The 2e^– WOR is expected to become a more sustainable and efficient method for producing H₂O₂ facilitated by continuing progress in the materials science and electrochemical technology fields.

Hydrogen peroxide (H₂O₂) is an important chemical and has been extensively used in various industrial and manufacturing applications, such as wastewater treatment, sterilization, energy storage, and oxidation of small molecules. With increasing demand in various fields, the global hydrogen peroxide market is expected to grow to $8.9 billion by 2031. Currently, over 90% of H₂O₂ is industrially synthesized by the anthraquinone process, which requires complex infrastructure and expensive catalysts. Additionally, the anthraquinone process is energy intensive and leads to increased levels of environmental pollution. Although the direct synthetic process, which involves mixing hydrogen and oxygen, can achieve high atomic utilization, its development is limited due to explosion risk and high cost. Thus, there is a pressing need for a safe, cost-effective, and efficient industrial method for the production of H₂O₂. The electrochemical synthesis of H₂O₂ via a two-electron oxygen reduction reaction (2e^- ORR) has emerged as an attractive method for the decentralized production of H₂O₂, which could effectively address the issues associated with the indirect anthraquinone and direct synthetic processes. However, sluggish reaction kinetics and poor selectivity decrease the energy efficiency of electrochemical H₂O₂ synthesis. In this regard, developing electrocatalysts with high 2e^- ORR selectivity is vital for the efficient production of H₂O₂. In the past decades, extensive efforts have been devoted to developing effective 2e^- ORR electrocatalysts such as noble metals/alloys, carbon-based materials, single-atom catalysts, and molecular complexes. However, the reported catalysts still have unsatisfactory catalytic performances. Therefore, there is still a long way to realize the large-scale production of H₂O₂ via electrochemical 2e^- ORR pathway. In this perspective, we systematically summarize recent developments regarding the direct production of H₂O₂ through electrochemical two-electron oxygen reaction. First, the fundamental aspects of electrochemical 2e^- ORR are discussed, including their reaction mechanisms, possible reaction pathways, testing techniques and performance figures of merit. This introduction is followed by detailed discussions on the different types of 2e^- ORR electrocatalysts, with an emphasis on the underlying material design principles used to promote reaction activity, selectivity, and stability. Subsequently, the applications of electrosynthetic hydrogen peroxide in various fields are briefly described, including pollutant degradation, water sterilization, energy storage, and small-molecule synthesis. Finally, potential future directions and prospects in 2e^- ORR catalysts for electrochemically producing H₂O₂ are examined.

Over the past three decades, significant advancements in lithium-ion battery technology have greatly improved human convenience, particularly in today's thriving electric vehicle industry. Further enhancements in the energy density, cycle life, and safety of lithium-ion batteries are crucial for the widespread adoption of electric vehicles. In recent years, transition metal layered oxides have garnered significant attention in the industrial power battery sector due to their advantages, including high specific capacity, commendable low-temperature performance, and cost-effectiveness. Increasing the nickel content and adjusting the charging cut-off voltage are recognized as effective means to enhance the energy density of transition metal layered oxides. However, these strategies tend to degrade cycling stability and thermal safety in conventional polycrystalline layered cathode materials. Benefiting from the mechanical stability of intact primary particles, the single-crystal structure of layered cathode materials can effectively mitigate intergranular cracking issues associated with high charging voltages. Nevertheless, due to the intrinsic structural properties of layered materials, single-crystal structures still face challenges related to sluggish Li⁺ transport kinetics, heterogeneous state of charge, anisotropic changes in lattice parameters, cation mixing, and chemo-mechanical degradation. The temporal and spatial evolution of the physicochemical properties within the internal microstructure of materials still requires comprehensive analysis using advanced operando characterization techniques. Currently, there is limited understanding of the intricate interplay between thermodynamics and kinetics in the synthesis process of single-crystal cathode materials. A more profound exploration of the structural degradation and synthesis mechanisms of single-crystal materials will serve as a fundamental basis for targeted modification strategies. Regrettably, existing single-crystal synthesis processes and modification approaches still fall short of market expectations. This shortfall is especially noticeable in future applications in solid-state batteries, where interface issues related to solid-state-electrolyte and cathode material are serious. Addressing these challenges necessitates the precise regulation of the microstructure of composite cathodes. Therefore, this review systematically analyzes and summarizes common issues related to the failure of both polycrystal and single-crystal structures, taking into account the intrinsic structural evolution at various temporal and spatial scales. We also outline strategies for regulating the synthesis process, element doping, and surface-interface modification of single-crystal nickel-rich layered cathode materials from the perspective of coherent structural design. We also intent to elucidate the essential connection between structural design and electrochemical performance. The microstructural design of single-crystal nickel-rich cathode materials should emphasize the alignment of lattice parameters between heterostructures and layered oxides, as well as the modulation of their spatial distribution, thereby ensuring the long-term efficacy of element doping and surface-interface modification. Finally, we offer a perspective on the future development of single-crystal nickel-rich cathode materials, highlighting their potential success in the realm of power batteries.

Silicon (Si) has a high theoretical gravimetric capacity (3579 mAh·g^-1 for Li₁₅Si₄), which is almost ten times higher than that of graphite (372 mAh·g^-1) anode. Besides, it has low electrochemical potentials (0.4 V vs. Li⁺/Li), and abundant reserves. Thus, Si becomes a key anode material for the development of high-energy lithium-ion batteries. Nano-Si, typically compounded with graphite, has opened its commercialization. But the specific capacity of commercial Si/graphite composites is generally below 600 mAh·g^-1, which is far below the theoretical specific capacity of Si. In the meanwhile, the high cost, high specific surface area and low tap density of nano-Si limit its volumetric energy density and large-scale production further. Compared to the above materials, micro-Si (1-10 μm) is gaining industry attention for its low cost, as it does not require high-energy ball milling to reduce the particle size. Also, low specific surface area and high tap density conduce to reducing interfacial side reactions and increasing volumetric energy density. Therefore, micro-Si has a particular advantage over application in high volumetric energy density storage devices. However, due to the huge stress caused by significant volume change (300%), there are more severe problems such as particle pulverization, electrode disintegration, conductive network failure and uncontrolled growth of solid electrolyte interphases, which greatly hinder its commercialization. Binders are essential in adapting to Si volume changes to ensure the integrity of the electrode and keeping the tight contact among the active material, conductive additive and current collector to provide a stable conductive network. The development of high-capacity and high-stability micro-Si-based anodes poses greater challenges to the design of binders. In this review, we first clarify the binding mechanism of binders, factors that influence the bonding forces, and design strategies of binders for relieving the volume change of Si electrodes. As a major part, we systematically discuss the strategies and corresponding mechanisms of functional binders for silicon-based anodes from aspects of self-healing binders, conductive binders, ion-conductive binders, and the facilitating effect of functional binders on the stable SEI (Solid Electrolyte Interphase) formation. Finally, the existing problems and challenges are pointed out in terms of long-cycle stability, initial Coulombic efficiency (ICE) and binder ratio under commercial loading. We put forward the promising directions for developing functional binders towards the practical use of micro-Si anode:an ideal binder should be multifunctional and helpful to robust electron/ion conductive networks and stable SEI throughout the long cycling life of micro-Si, where the polymer molecular structure of functional binders can be systematically designed by artificial intelligence and machine learning technologies.

Efficiently converting CO₂ and H₂O into value-added chemicals using solar energy is a viable approach to address global warming and the energy crisis. However, achieving artificial photocatalytic CO₂ reduction using H₂O as the reductant poses challenges is due to the difficulty in efficient cooperation among multiple functional moieties. Metal-organic frameworks (MOFs) are promising candidates for overall CO₂ photoreduction due to their large surface area, diverse active sites, and excellent tailorability. In this study, we designed a metal-organic framework photocatalyst, named PCN-224(Zn)-Bpy(Ru), by integrating photoactive Zn(II)-porphyrin and Ru(II)-bipyridyl moieties. In comparison, two isostructural MOFs just with either Zn(II)-porphyrin or Ru(II)-bipyridyl moiety, namely PCN-224-Bpy(Ru) and PCN-224(Zn)-Bpy were also synthesized. As a result, PCN-224(Zn)-Bpy(Ru) exhibited the highest photocatalytic conversion rate of CO₂ to CO, with a production rate of 7.6 µmol·g⁻¹·h⁻¹ in a mixed solvent of CH₃CN and H₂O, without the need for co-catalysts, photosensitizers, or sacrificial agents. Mass spectrometer analysis detected the signals of ¹³CO (m/z = 29), ¹³C¹⁸O (m/z = 31), ¹⁶O¹⁸O (m/z = 34), and ¹⁸O₂ (m/z = 36), confirming that CO₂ and H₂O acted as the carbon and oxygen sources for CO and O₂, respectively, thereby confirming the coupling of photocatalytic CO₂ reduction with H₂O oxidation. In contrast, using PCN-224-Bpy(Ru) or PCN-224(Zn)-Bpy as catalysts under the same conditions resulted in significantly lower CO production rates of only 1.5 and 0 µmol·g⁻¹·h⁻¹, respectively. Mechanistic studies revealed that the lowest unoccupied molecular orbital (LUMO) potential of PCN-224(Zn)-Bpy(Ru) is more negative than the redox potentials of CO₂/CO, and the highest occupied molecular orbital (HOMO) potential is more positive than that of H₂O/O₂, satisfying the thermodynamic requirements for overall photocatalytic CO₂ reduction. In comparison, the HOMO potential of PCN-224(Zn)-Bpy without Ru(II)-bipyridyl moieties is less positive than that of H₂O/O₂, indicating that the Ru(II)-bipyridyl moiety is thermodynamically necessary for CO₂ reduction coupled with H₂O oxidation. Additionally, photoluminescence spectroscopy revealed that the fluorescence of PCN-224(Zn)-Bpy(Ru) was almost completely quenched, and a longer average photoluminescence lifetime compared to PCN-224(Zn)-Bpy and PCN-224-Bpy(Ru) was observed. These suggest a low recombination rate of photogenerated carriers in PCN-224(Zn)-Bpy(Ru), which also supported by the higher photocurrent observed in PCN-224(Zn)-Bpy(Ru) compared to PCN-224(Zn)-Bpy and PCN-224-Bpy(Ru). In summary, the integrated Zn(II)-porphyrin and Ru(II)-bipyridyl moieties in PCN-224(Zn)-Bpy(Ru) play important roles of a photosensitizer and CO₂ reduction as well as H₂O oxidation sites, and their efficient cooperation optimizes the band structure, thereby facilitating the coupling of CO₂ reduction with H₂O oxidation and resulting in high-performance artificial photocatalytic CO₂ reduction.

In recent decades, the oxygen evolution reaction (OER) has attracted significant attention because of its critical role in energy storage and conversion technologies. This reaction requires highly efficient catalysts such as IrO₂ and RuO₂ to accelerate its slow reaction rate. Among existing developed low-cost materials, NiFe layered double hydroxides (NiFe LDH) have demonstrated great potential for use in OERs in alkaline electrolytes with low overpotential (200–300 mV at 10 mA∙cm^-2). Extensive efforts have been devoted to developing efficient electrocatalysts based on NiFe LDHs; Further reducing their overpotential can be a challenging task. To overcome this bottleneck, it is necessary to clearly identify the catalytic mechanism and active sites and finding new solutions to obtain catalysts with ultra-low overpotential. Through this review, we thoroughly examined the structure, composition, and development history of NiFe LDHs. Despite the extensive investigation of the catalytic active sites and mechanism, it still remains elusive and controversial. Herein, existing studies that have aimed to elucidate the catalytic sites are presented and comprehensively analyzed, providing an insightful understanding of the catalytic mechanism and active sites of NiFe LDHs. Additionally, various strategies, such as heteroatom doping and the introduction of vacancies, have been proposed to enhance the catalytic activities of these materials. Considering the electronic and geometrical structures of NiFe LDHs, this review summarizes and categorizes activity enhancement methods based on different enhancement mechanisms, offering new insights and directions for developing high-performance NiFe LDH-based catalysts. Furthermore, despite being crucial to the practical use of the catalyst, catalyst stability is often overlooked, especially under technological conditions such as high current densities. Recent works have suggested that NiFe LDH-based catalysts suffer severe activity fading under high current densities after a short period of operation. It is important to update recent research on the stability of these catalysts. This review emphasizes the stability issues of NiFe LDH-based catalysts to draw more attention toward research and analyses related to the decay mechanisms of these catalysts. We have summarized and discussed the recent strategies that have been proposed to reduce the stability problem developed based on these decay mechanisms. Finally, the review concludes with a discussion of possible directions for producing NiFe LDHs with extraordinary catalytic activities and stabilities.

Photocatalytic reduction of CO₂ into value-added chemicals is a feasible approach to harvest solar light energy and storing energy in the form of chemical fuels as well as to mitigate the effects of global climate change and help achieve an artificial carbon cycle. However, the efficiency of CO₂ photoreduction is low for commercial purposes. This is mainly due to the difficult adsorption and activation process of CO₂ molecules, the unsatisfactory selectivity of target products, and the uncontrolled-subsequent reaction process of the generated carbon products. CO₂ photoreduction requires substantial electrons for participation. Hence, these issues are due to the electron density modulation of the active sites of catalysts. Unfortunately, the CO₂ photoreduction process involves multi-fundamental steps, which leads to different requirements in electron density modulation. The performance might not be effectively improved by directly enhancing or weakening the total electron density of active sites. In this paper, we summarize recent advances in the influence of electron density variation of the active sites in strengthening the adsorption and activation of CO₂ molecules, enhancing the selectivity of target carbon products and modulating the subsequent reaction process of the generated carbon products. This review begins with the effect of different types of active sites in strengthening the adsorption and activation of the CO₂ molecules and the related methods for modulating the electron density of active sites. Active sites with high electron densities can significantly enhance the adsorption and activation of CO₂. Introducing metal and fabricating the defects on catalyst surfaces are effective strategies for fabricating the electron-rich active sites. After that, we discuss the influence of electron density variation in enhancing the selectivity of target carbon products in detail. In this part, the related effects in the multielectron donation from the catalyst surface, the reactive intermediates, and the competition hydrogen evolution reaction are summarized. Enhancing the electron density of active sites strengthens the former two processes. For multielectron donation, introducing cocatalysts or fabricating heterostructures are the most effective methods for enhancing the electron density of active sites. The adsorption and conversion process of intermediates are mainly affected by the accumulation sites of electrons. The active sites with low coordination are more favorable to achieving the generation of multi-electronic carbon products. In contrast, the hydrogen evolution reaction is significantly inhibited by reducing the electron density of active sites. Moreover, elemental doping is considered one of the most effective strategies. Finally, we describe the method for weakening the electron density of active sites to promote product desorption and inhibit the photooxidation of reactive products.

The continuous developments in physical chemistry, improved methodology, and advanced techniques have spurred interest in chemical reaction at the microscopic scale. Experimental manipulation techniques at the microscopic level are demanded to enable in-depth studies regarding the regulation of chemical reactions, material structures, and properties. The development and application of microscopic research methods have become an emerging trend in physical chemistry. Techniques featuring the use of optical, magnetic, and acoustic tweezers have been developed to manipulate objects at the microscopic scale. Optical tweezers use momentum transfer between light and objects to manipulate objects and can stably trap and manipulate mesoscopic particles, even single molecules, by exerting pico-newton force. With advantages including non-invasiveness, non-damaging, and ultra-high sensitivity, optical tweezers are ideal for studying individual molecules, molecular aggregates, condensed matter, chemical bonds, and intermolecular interactions. This technique has the potential to revolutionize the fields of chemistry, physics, information technology, and life sciences. Arthur Ashkin was awarded the 2018 Nobel Prize in Physics for his contribution to the development of this technique. The trapping force of the conventional optical tweezers technique originates from the light intensity gradient. Because of the diffraction limit of light, the trapping and manipulation of micro-nano objects < 100 nm in size with traditional optical tweezers is difficult. However, simply increasing the optical power used for trapping induces serious thermal effects and photodamage. By developing unique materials and structures coupled with optical tweezers, researchers have broken the diffraction limit of light and achieved sub-nanometer single-molecule trapping. In this review, we summarize the recent advances in the application of various optical tweezers techniques in physical chemistry and demonstrate the technical principles of fiber, photonic crystal, and plasmonic optical tweezers, respectively. We focus on the development and application of plasmonic optical tweezers and single-molecule plasmonic optical trapping based on tunable nanogaps. Generally, optical tweezers can realize the trapping and manipulation of molecular-scale particles via two main technical routes. The first route is improving the laser focusing ability through unique optical path design and optical component fabrication. The second involves enhancing the trapping field through ingenious auxiliary structure design. Finally, we present the promising future developments and applications of optical tweezers technology.

The anode-free solid-state lithium battery (AFSSLB) is a type of lithium battery that utilizes an initial charging process to generate lithium metal as the anode. With a 1: 1 anode-to-cathode capacity ratio, it enables any lithiated cathode system to achieve a maximal energy density. Furthermore, the incorporation of inorganic solid electrolytes in the AFSSLB greatly enhances its intrinsic safety. However, the AFSSLB faces challenges related to interfacial issues between the electrolyte and collector. During the cycling process, uneven lithium-ion flux can result in contact loss and dendrite growth, ultimately leading to rapid battery failure. Addressing these interfacial problems is crucial for the successful implementation and performance of AFSSLBs. The absence of initial lithium metal material prevents the battery system from accommodating additional lithium through a modified anode. Instead, it relies on high Coulomb efficiency during cycling. Consequently, ensuring continuous and uniform contact at the anode interface is crucial for maintaining the reversibility of lithium deposition. Herein, a nanocomposite current collector is introduced to enhance the interface between the collector and electrolyte in AFSSLB. In this approach, silver nanoparticles are dispersed within the carbon materials to construct a composite current collector. The incorporation of the silver-carbon nanocomposite layer results in a low interfacial impedance of 10 Ω·cm^-2, indicating that the electrolyte-collector interface maintains contact throughout the charging and discharging processes. The focused ion beam (FIB) technology and electron microscopy were employed to analyze the battery cross sections, revealing that lithium metal could be deposited in a thickness of more than 25 μm without short-circuiting using this silver-carbon nanocomposite current collector. The solid-state batteries equipped with nanocomposite current collectors exhibited an enhanced dissolution of silver in the lithium metal, leading to the formation of abundant lithiophilic sites. The nanocomposites facilitate the rapid transfer of Li atoms within the anodes, thus achieving uniform lithium metal deposition. Theoretical analysis using the nucleation equation demonstrates that using nano-silver as a current collector can reduce the nucleation work required for deposition by at least four orders of magnitude. The smaller nucleation force contributes to the uniform and stable deposition of lithium metal during continuous cycling. The solid-state batteries demonstrated improved interfacial contact, resulting in the uniform and stable lithium metal deposition of over 7.0 mAh·cm^-2 for more than 200 cycles at 0.25 mA·cm^-2. The cycling performances of all-solid-state batteries can be significantly improved through the design of nanocomposite collectors. This presents an effective strategy for advancing the practical implementation of all-solid-state lithium metal batteries, particularly those utilizing an anode-free configuration.

Rechargeable lithium-ion batteries (LIBs) have garnered global attention as a prominent solution for storing intermittent renewable energy, addressing energy scarcity, and mitigating environmental pollution. In the previous century, Sony introduced the "lithium-ion battery" concept, heralding a new era for LIBs and effectively bringing them into commercial use. The initial commercially available LIBs utilized lithium cobalt oxide as the cathode material and graphite as the anode material. Capitalizing on their attributes encompassing elevated energy density, substantial specific capacity, portability, and ecological compatibility, LIBs have secured substantial market share throughout the commercialization trajectory. Their commercial viability and scope have been markedly enhanced through the continuous advancement of LIBs' cathode materials and innovative implementations encompassing battery design, assembly, and thermal management. In recent years, the rapid expansion of sectors such as cellular phones and new energy vehicles, coupled with the drive towards "carbon peaking" and "carbon neutrality," has propelled the robust growth of the LIBs sector, which has resulted in widespread adoption across diverse industrial domains and daily applications spanning road transportation, materials, chemicals, and information technology. However, the swift proliferation of the LIBs industry has incited an influx of end-of-life (EOL) batteries, which pose risks of flammability, explosiveness, and the presence of toxic and hazardous elements, including fluorides. These aspects collectively pose a formidable environmental and human health hazard, warranting urgent and harmless disposal measures. Simultaneously, EOL LIBs are rich reservoirs of resources like lithium, nickel, cobalt, and manganese, boasting metal contents in cathode waste that significantly exceed those found in their natural mineral counterparts, presenting a substantial opportunity for resource reclamation. Therefore, extracting valuable metals from LIBs cathode waste simultaneously addresses critical environmental and human health concerns linked to improper EOL LIBs disposal while playing a pivotal role in mitigating metal resource shortages. This dual-purpose endeavor aligns with the overarching goal of promoting sustainable resource circulation. The recovery of LIBs cathode materials is a central topic of global research discussion. This study comprehensively overviews valuable metal extraction from LIBs cathode waste using hydrometallurgical methodologies. It delves deeply into diverse approaches encompassing inorganic, organic, and deep eutectic solvents (DESs), scrutinizing environmental, technical, and industrial feasibilities. The objective is to optimize extraction techniques and mitigate their environmental impact. Furthermore, this paper meticulously discusses the utilization of environmentally friendly reducing agents like green biomass waste, coupled with the efficient and eco-conscious EOL LIBs internal cycle mechanical activation technology, to enhance the leaching of valuable metals from cathode waste. This inquiry culminates in identifying potential research avenues and challenges within the EOL LIBs recycling process.

Large-scale hydrogen production through the electrochemical water splitting technique is an important way for addressing the impending energy and environmental crisis. This approach requires highly efficient and robust bifunctional cost-effective electrocatalysts. Engineering amorphous and crystalline phases within electrocatalysts is a key method for enhancing the catalytic kinetics of water electrolysis, due to their unique physicochemical properties. The interface and amorphous regions constructed within heterostructures serve as highly active sites that play a crucial role in electrochemical reactions. On the other hand, highly crystalline regions within the heterostructure demonstrated high tolerance in harsh environments, which helps to improve the stability of the overall catalyst. However, effectively tailoring the crystalline state of catalysts within a microenvironment presents a significant challenge. Herein, construction of a novel CrS/CoS₂ heterojunction with precise control over crystallinity were presented. The optimized amorphous CrS/highly crystalline CoS₂ heterojunction (A-CrS/HC-CoS₂) exhibits a low overpotential of 90.6 mV (at 10 mA∙cm⁻²) and 370.5 mV (at 50 mA∙cm⁻²) for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations reveal that charge redistribution induces variations in the d-band center value at the A-CrS/HC-CoS₂ heterostructure interface, enhancing the catalytic activity for both HER and OER. The displacement of the d-band due to charge redistribution in the Cr―S―Co bond within A-CrS/HC-CoS₂ contributes to the modulation of the adsorption capacity of H* and OOH* intermediates on the catalyst surface, thereby optimizing the rate-determining step for HER and OER. The amorphous/highly crystalline structure also facilitates the structural and compositional evolution of A-CrS/HC-CoS₂ during water electrolysis, ensuring excellent stability. As a bifunctional catalyst in a methanol-assisted energy-saving hydrogen production device, A-CrS/HC-CoS₂ operates at a low cell voltage of 1.51 V to deliver a current density of 10 mA∙cm⁻², making it a promising candidate among metal-based catalysts. The well-preserved amorphous/crystalline heterointerfaces in A-CrS/HC-CoS₂, along with favorable changes in surface composition, contribute to robust HER and OER stability. This work provides valuable insights into the manipulation of catalytic activity through crystalline control within amorphous/crystalline heterojunctions for bifunctional transition metal compound electrocatalysts.

All-solid-state batteries (ASSBs) using inorganic solid electrolytes (SEs) have emerged as crucial components in energy storage applications due to their superior safety and cycle life. In recent years, due to the extensive developments of SEs with high room temperature ionic conductivity (> 10^-3 S·cm^-1), the sluggish diffusion kinetics of lithium ions in SEs are no longer the primary bottleneck impeding the enhancement of ASSBs. On the contrary, the notable resistance at the cathode/SE interface has emerged as a pressing issue demanding immediate resolution. The interfacial resistances arising from various factors, including the formation of the space-charge layer, interfacial chemical reactions, and lack of intimate contact, stand as fundamental reasons for a range of performance deteriorations, such as short cycling life, low coulombic efficiency, and poor power performance. These interconnected aspects further result in differences in the orders of magnitude of the reported interfacial resistances at different fabrication temperatures and/or routes, even within the same material system. Among these factors, the solid-solid contact or chemical reaction degree is closely related to the structural and electronic properties of the selected cathode and SE materials. The observed space-charge layer effect is universal and independent of the specific components or types of ion-conductive materials. Thus, obtaining a comprehensive understanding of the physics governing the space-charge layer at the interfaces of ASSBs is pivotal for researchers to fundamentally address the high interfacial resistance stemming from it. This forms the foundation for incorporating other mechanisms (such as interfacial reactions) to more accurately quantify interfacial resistance and expedite interface research in ASSBs. In this review, we strictly derive the theoretical model of the formation of the space-charge layer caused by the inherent chemical potential difference between the cathode and SE from fundamental concepts of (electro)chemical potential and electric potential, and reveal the physical picture of its influence on interfacial resistance. Subsequently, the most recent experimental characterizations and theoretical calculations of the space-charge layer at the cathode/SE interface are comprehensively discussed. While the existence of the space-charge layer is observable through experimentation, its characterization is complicated by factors like loss of interfacial contact and interfacial reactions. Therefore, it becomes imperative to further quantify the concentration of lithium ions in the space-charge layer and its impact on interfacial resistance through theoretical calculations. However, when combining the space-charge layer model with numerical and first-principles calculations to quantitatively study interfacial resistance, accurately determining the interfacial electric potential difference at the cathode/SE interface remains challenging, resulting in several orders of magnitude difference between predicted results and experimental measurements. Consequently, grounded in the foundational physical framework of the interfacial electric potential difference, the intricate connections between this potential difference and the electronic structure of the cathode/SE interface are explored. As a result, a strategy is proposed to ascertain the interfacial electric potential difference by directly calculating the Fermi level of the cathode and SE under real bonding conditions. This endeavor is anticipated to broaden the utility of the space-charge layer model in quantitatively calculating cathode/SE interfacial resistance, offering valuable insights for optimizing the cathode/SE interface and enhancing the overall performance of ASSBs.

Hexavalent chromium (Cr(VI)) may be a hazardous and non-biodegradable waste matter which will cause substantial environmental damage. Fabricating powerful photosystems to achieve efficacious elimination of Cr(VI) holds eminent promise in solving environmental issues. Thanks to their outstanding photo/electrical properties, large surface area, and customizable structure, metal-organic framework (MOF) catalysts have attracted widespread attention within the field of pollutant degradation and reduction. Nevertheless, due to the recombination of photo-generated charge carriers, pristine semiconductor MOFs’ photocatalytic performance is inadequate. To overcome this challenge, one of the most typical and effective strategies is to create heterojunctions by combining MOFs with another semiconductor. Among these strategies, the innovative step-scheme (S-scheme) heterojunction has gained increasing prominence. Unlike traditional type II and Z-scheme heterojunctions, the built-in electric field at the S-scheme heterojunction boundary enhances spatial charge separation and boosts redox capacity, thereby improving photocatalytic performance. In this study, a creative MOF-based S-scheme architecture with oxygen vacancies (OV) was built via in situ growth of MIL-101(Fe) crystals on the surface of OV-rich BiOCl microspheres. The optimized MIL-101(Fe)/BiOCl heterojunction exhibited exceptional photocatalytic performance in photo-reducing high concentrations of Cr(VI) and 88.5% of Cr(VI) solution (10 mg·L^-1, 100 mL) can be removed within 60 min, which is about 4.4 and 9.0 times that of BiOCl and MIL-101(Fe). Besides, the MIL-101(Fe)/BiOCl manifests impressive practical implementation prospect due to its high anti-interference property, robustness and reusability. Photoelectron spectroscopy results validated that built-in electric field, bending band, and Coulomb attraction facilitated the transition of photoelectrons from the conduction band (CB) of BiOCl to the valence band (VB) of MIL-101(Fe), where they recombined with the photo-created holes. This suggests an S-scheme interfacial photo-carrier detachment mechanism at the MIL-101(Fe)/BiOCl interface. In addition, BET measurements indicated a notable increase in surface area with the introduction of MIL-101(Fe). The OV-rich S-scheme MIL-101(Fe)/BiOCl heterostructure boasts more reactive sites, enhanced interfacial charge separation, and optimal redox ability of photo-carriers, leading to enhanced photocatalytic properties. Measurements of active radical scavenging and electron spin resonance (ESR) confirm that e^- and ·O₂^- are the primary active species during photocatalysis. These discoveries would open up new avenues for developing defective semiconductor/MOF S-scheme photocatalyst for environmental purification.

Amidst widespread consumption and the scarcity of non-renewable fossil fuels, the advancement of clean energy sources like solar and wind energy holds immense significance. Nevertheless, these clean energy sources grapple with unstable power supply, underscoring the pressing need for the enhancement of large-scale energy conversion and storage devices. Zinc-air batteries, boasting high energy density, safety, affordability, ease of assembly, eco-friendliness, and abundant zinc metal resources, exhibit promising potential as energy storage and conversion solutions. Nevertheless, various challenges persist in their application, including a limited cycle life and inadequate power density. Throughout the charge and discharge cycles, factors such as the dendritic growth of the zinc negative electrode, the formation of ZnO passivation layers, electrolyte evaporation, and side reactions involving the diffusion of zincate ions to the positive electrode collectively exert influence on the performance of zinc-air batteries. The separator plays a crucial role in zinc-air batteries by isolating the positive and negative electrodes to prevent short circuits, and these aforementioned issues can be resolved through optimization of the design. Until now, the commonly employed separators in zinc-air batteries can be categorized into various types:standard porous separators, anion exchange membranes, polymer gel electrolyte membranes, and composite membranes comprising diverse polymer compositions. Among these, within the context of separator research, porous separators of the polyolefin type are generally utilized in aqueous alkaline zinc-air batteries. Nevertheless, their pronounced hydrophobic nature results in markedly diminished ion conductivity. Conversely, gel-based solid-state or semi-solid-state electrolyte membranes are tailored for flexible electronic device applications. This adaptation ensures that zinc-air batteries uphold favorable electrochemical performance even under deformation conditions, simultaneously addressing the challenge of electrolyte volatilization to a certain degree. Fundamental attributes of the separator, such as pore size, hydrophilicity, and other properties, significantly impact the battery's lifespan and charge/discharge performance. Nevertheless, research on separators and their modifications to enhance zinc-air battery performance, along with the underlying principles, lags behind other aspects of zinc-air battery research, presenting ample room for advancement. This review offers a concise overview of zinc-air battery development, using aqueous alkaline zinc-air batteries as an example to elucidate their operational principles. The objective is to grasp the challenges leading to battery failure in different components and to particularly analyze how separator performance influences overall battery efficiency. This includes aspects such as ion selectivity, ion conductivity, stability, and water retention of the separator. The overview is divided into two main sections:(1) elucidating the fundamental structure and operational principles of the zinc-air battery, and (2) comprehensively exploring the fundamental attributes of the separator and its pivotal function within the zinc-air battery. The research progress and perspective for the development of zinc-air battery separators are also discussed and anticipated.

This paper provides a comprehensive overview of the establishment and subsequent adjustment to the discipline codes of Physical Chemistry in China. In light of the research developments in Physical Chemistry over the past decade, the optimized reclassification into Catalysis & Surface Interface Chemistry and Chemical Theory & Mechanism, effective from 2018, plays an important role in advancing cutting-edge foundational researches and enhancing the grant effectiveness of science foundation. Constructive insights and recommendations are provided for further optimizing discipline allocation, serving as a valuable guide for shaping future development strategies within the field of Physical Chemistry.

Electrochemical water splitting proves critical to sustainable and clean hydrogen fuel production. However, the anodic water oxidation reaction—the major half-reaction in water splitting—has turned into a bottleneck due to the high energy barrier of the complex and sluggish four-electron transfer process. Nickel-iron layered double hydroxides (NiFe-LDHs) are regarded as promising non-noble metal electrocatalysts for oxygen evolution reaction (OER) catalysis in alkaline conditions. However, the electrocatalytic activity of NiFe-LDH requires improvement because of poor conductivity, a small number of exposed active sites, and weak adsorption of intermediates. As such, tremendous effort has been made to enhance the activity of NiFe-LDH, including introducing defects, doping, exfoliation to obtain single-layer structures, and constructing arrayed structures. In this study, researchers controllably doped NiFe-LDH with tungsten using a simple one-step alcohothermal method to afford nickel-iron-tungsten layered double hydroxides (NiFeW-LDHs). X-ray powder diffraction analysis was used to investigate the structure of NiFeW-LDH. The analysis revealed the presence of the primary diffraction peak corresponding to the perfectly hexagonal-phased NiFe-LDH, with no additional diffraction peaks observed, thereby ruling out the formation of tungsten-based nanoparticles. Furthermore, scanning electron microscopy (SEM) showed that the NiFeW-LDH nanosheets were approximately 500 nm in size and had a flower-like structure that consisted of interconnected nanosheets with smooth surfaces. Additionally, it was observed that NiFeW-LDH had a uniform distribution of Ni, Fe, and W throughout the nanosheets. X-ray photoelectron spectra (XPS) revealed the surface electronic structure of the NiFeW-LDH catalyst. It was determined that the oxidation state of W in NiFeW-LDH was +6 and that the XPS signal of Fe in NiFeW-LDH shifted to a higher oxidation state compared to NiFe-LDH. These results suggest electron redistribution between Fe and W. Simultaneously, the peak area of surface-adsorbed OH increased significantly after W doping, suggesting enhanced OH adsorption on the surface of NiFeW-LDH. Furthermore, density functional theory (DFT) calculations indicated that W(Ⅵ) facilitates the adsorption of H₂O and O^*-intermediates and enhances the activity of Fe sites, which aligns with experimental results. The novel NiFeW-LDH catalyst displayed a low overpotential of 199 and 237 mV at 10 and 100 mA∙cm⁻² in 1 mol∙L⁻¹ KOH, outperforming most NiFe-based colloid catalysts. Furthermore, experimental characterizations and DFT+U calculations suggest that W doping plays an important role through strong electronic interactions with Fe and facilitating the adsorption of important O-containing intermediates.

Owing to the growing consumption of non-renewable resources and increased environmental pollution, significant attention has been directed toward developing renewable and environmentally friendly energy sources. Hydrogen has emerged as a clean energy carrier and is considered an ideal chemical for power generation via fuel cells. Using renewable energy to power hydrogen production is an attractive prospect, and hydrogen production through photoelectrochemical water splitting is considered a promising area of interest; consequently, significant research is being conducted on rationally designed photoelectrodes. Generally, a photocathode for hydrogen evolution must have a conduction band that is more negative than the reduction potential of hydrogen. Numerous photocathode materials have been developed based on this premise; these include p-Si, InP, and GaN. Compared with other photocathode materials, Cu-based compounds are advantageous owing to their low preparation costs and diverse chemical states. For example, Cu₂O is a non-toxic p-type metal oxide semiconductor material with an appropriate band structure for water splitting and a direct band gap of 1.9–2.2 eV. Furthermore, the production of Cu₂O is facile, and the required materials are abundant; thus, it has attracted significant interest as a material for photocathodes. However, Cu₂O suffers from rapid recombination of photogenerated carriers and severe photo-corrosion, leading to unsatisfactory efficiency and poor stability. Intrinsically, the poor photo-stability of Cu₂O can be attributed to the location of the redox potential of Cu₂O within its bandgap, owing to which photoelectrons tend to preferentially reduce Cu₂O to Cu rather than reduce water to reduction. Therefore, Cu₂O itself is not an ideal hydrogen evolution catalyst. Thus, co-catalysts are necessary to improve its hydrogen evolution activity and photostability. In addition to co-catalysts, combining Cu₂O with tailored n-type semiconductors to generate built-in electric fields of p–n junctions has attracted extensive attention owing to its ability of increasing the separation of photogenerated carriers. Similarly, applying a hole transfer layer on the substrate can promote photocarrier separation. Furthermore, considering that water is indispensable for Cu₂O reduction, one effective approach to improve the stability of Cu₂O is the addition of a protective/passivation layer to isolate Cu₂O from water in aqueous electrolytes. In this review, we provide a brief overview of the mechanism of photoelectrochemical water splitting and the band structure of Cu2O; preparation methods of Cu₂O photocathodes; strategies to improve the efficiency and stability of Cu₂O photocathodes, including the construction of p–n junctions, integration with co-catalysts, and modifications using hole transport layers; advanced photoelectrochemical characterization techniques; and a discussion regarding the direction of future photocathode research.

Since the initial report on multiple resonance thermally activated delayed fluorescence (MR-TADF) molecules, their narrow band emissions, high quantum yields and other characteristics have consistently fueled research interest in the realm of organic electronics, particularly organic light emitting diodes (OLED). These molecules swiftly ascended to the forefront of research, serving as a pivotal focus, giving rise to numerous high-performance devices and meticulously crafted molecules. Devices featuring MR-TADF molecules as the luminescent core continually redefine our comprehension of OLED, with some employing hyperfluorescence technology attaining peak performance in specific photochromic domains today. Presently, with the escalating demand for ultra-high-resolution displays, the international telecommunication union (ITU) has unveiled the next generation color gamut standard, BT.2020. This standard delineates the broadest display color gamut, mandating monochromatic primary color wavelengths of 467, 532, and 630 nm, constituting an exceptionally extensive color gamut. Simultaneously, achieving high-resolution displays with such an expansive color gamut imposes unprecedentedly stringent requirements on the color purity of device elements. Consequently, it imposes a formidable color purity target for display technology. In the past, traditional fluorescent materials struggled to meet these demands. The advent of BT.2020, however, has presented new opportunities for the advancement of MR-TADF molecules, leading to a surge in popularity in this field. In recent years, with copious research and practical applications, the MR-TADF molecular family has undergone rapid evolution. Nevertheless, discussions and summaries primarily centered on the field's development, with limited focus on molecular design strategies. This deficiency hinders adequate reference for researchers entering the field. Consequently, this article expounds upon the design principles of select MR-TADF molecules reported in the past three years. It delves into aspects such as the X-π-X principle, fast reverse intersystem crossing processes, narrow-band emission, and high oscillator strength. Additionally, it posits future design directions, including the incorporation of non-traditional structures into the MR-TADF domain. Finally, the article offers suggestions for the prospective development and industrialization of the MR-TADF field.

Non-renewable energy sources such as fossil fuels are increasingly depleted. In order to cope with the potential energy crisis, it is urgent to develop clean and efficient renewable energy sources. Advanced energy storage technology based on electrical energy holds critical significance to the sustainable and steady development of human society. Aqueous rechargeable batteries are a kind of promising electrochemical energy storage devices. Zinc-ion batteries (ZIBs) are gaining increasing popularity due to their safety, sustainability, cost-effectiveness and high energy density, positioning them as potential successors to current Lithium-ion batteries (LIBs) with a high degree of commercialization. The extraordinary mechanical flexibility and excellent electrochemical performance exhibited by ZIBs holds great significance in advancing the development of flexible and wearable batteries. Manganese-based oxides with large channel size possess the characteristics of high theoretical capacity, various oxidation states (including +2, +3, +4) and low cost, which are commonly employed as cathode materials for AZIBs. Nevertheless, the electrochemical performance of current manganese-based ZIBs is not satisfactory, facing the challenges of metal dissolution, material structure instability, notably a strong electrostatic interaction exhibited by divalent Zn²⁺ ions in the host structure resulting in slow transmission kinetics. These challenges contribute to low cycle stability of the battery, impeding practical application and the progression of ZIBs. To solve these problems, diverse structural engineering strategies including defect engineering have been exploited, which can effectively improve the transport kinetics of zinc ions. From the perspective of enhancing the performance of the material itself, interlayer intercalation and other measures can be taken to better the microstructure or morphology of manganese-based materials. By improving the electrical conductivity of the material and enhancing ionic bonding, the structural stability and electrochemical performance of the material can be effectively improved. And from the angle of battery design, in order to improve the stability of the electrode-electrolyte interface, the electrolyte is optimized, or a fresh preparation method different from the conventional slurry coating process is adopted, which is also a promising method to design a new electrode without binder and the electrode components can still be evenly distributed. This review provides an overview of Zinc-ion storage mechanisms:the reversible Zn²⁺ insertion/extraction; the reversible interposition and deintercalation of Zn²⁺ and H⁺; the chemical conversion reactions, and the mechanism of dissolution-deposition reaction. Furthermore, the challenges faced by manganese-based cathode materials are clarified, and the optimization strategies to improve their electrochemical performance by increasing active sites, reducing solid-state diffusion energy barriers, inhibiting the dissolution of active substances, and improving material stability are highlighted. Finally, the practical application and potential of ZIBs assembled by manganese-based cathode materials in biomedical equipment and other electronic devices are also discussed.

The theoretical and experimental technologies used for electrochemical characterization methods, which are essential for determining surface structures and elucidating electrochemical reaction mechanisms, have been significantly improved after more than two centuries of development. Traditional chemical methods like cyclic voltammetry (CV) can provide the exact electrochemical reaction rate in different potential ranges, which is beneficial for identifying the electrochemical performance of electrocatalytic materials. However, traditional chemical methods alone are often inadequate when it comes to achieving a deep understanding of reaction mechanisms. In this regard, spectroscopic methods, which are powerful tools to identify the active sites and intermediate species during electrochemical reactions, are widely applied to elucidate the electrochemical mechanism at a molecular or even atomic level. In this review, three molecular-vibration-spectroscopy-based electrochemical characterization technologies, viz., infrared (IR) spectroscopy, surface-enhanced Raman spectroscopy (SERS), and sum frequency generation (SFG) spectroscopy, are comprehensively reviewed and discussed. IR, SERS, and SFG are all non-destructive spectroscopic techniques with ultra-high surface sensitivity and are indispensable when detecting surface species during electrochemical reactions. Consequently, researchers have strived to combine these spectroscopic techniques with basic electrochemical instruments. In fundamental electrochemical research, detecting electrochemical reactions in model single-crystal systems and determining the structure of interfacial water molecules have been two major research topics in recent years. Single-crystal surfaces are important in fundamental electrochemical research because of their defined atom arrays and energy states, serving as model systems to help bridge experimental results and theoretical calculations. Meanwhile, the structure of interfacial water influences most electrochemical reaction processes, and as such, probing interfacial water structures is a challenging but valuable target in fundamental electrochemical research. Additionally, the application of electrochemical spectroscopic methods to analyze fuel cells has become important, and this review covers recent SERS studies of oxygen reduction reactions (ORR) and hydrogen oxidation reactions (HOR) in hydrogen fuel cells. Concurrently, electrochemical IR and SFG studies on the electrooxidation of small organic molecules are discussed. Finally, owing to the significance of lithium-ion batteries, studies of electrochemical spectroscopic methods on solid electrolyte interphase (SEI) and cathode-electrolyte interface (CEI) are becoming increasingly important and are introduced here. In conclusion, recent advances and the future developments of electrochemical spectroscopy methods are summarized in this review article.

Nanoscale metallic catalysts are garnering increased attention in the advancement of electrochemical energy conversion technologies. The precise control of nanocrystal morphology, size, and crystalline structures offers the ability to manipulate electronic properties and enhance intrinsic catalytic performance. Consequently, a profound understanding of the nanocrystal growth mechanism becomes imperative for the design and production of highly active catalysts. However, mechanism studies in colloidal methods generally depend on operando technics and the development is hindered by expensive cost and limited resources. And high-temperature or high-pressure reaction conditions always bring trouble for the application of the equipment, so the in situ methods have been widely used. While ex situ methods need to detach the samples from the reaction environment, which might lose information about the process and thus fail to reflect the real situation. Furthermore, in conventional methods, the use of macromolecular organics to regulate crystal morphology results in intricate post-treatment processes, and any residual substances can adversely affect catalyst performance. Electrochemical synthesis offers a clean and controllable protocol for producing metallic nanocrystals and supported heterogeneous nanoparticle catalysts. In this review, building upon the classic principles of crystal growth in chemical colloidal methods and electrodeposition, it is proposed that the processes occurring during crystal formation could be visualized or monitored through electrochemical tests. By fine-tuning electrochemical parameters and refining deposition procedures, nucleation density and growth rates along specific facet orientations of nanocrystals can be precisely managed. Electrochemical signals provide insights into in-situ reduction and deposition behaviors at the electrode-electrolyte interfaces through professional analysis. The direct loading of nanocrystals onto substrates amplifies their synergistic effects, mitigates exfoliation issues, and consequently enhances catalytic activity and stability. Additionally, due to its broader potential window compared to H₂O, non-aqueous liquids hold promise as a solution for preparing active metals and alloys that exhibit distinctive catalytic performance. Furthermore, electrochemical methods facilitate the synthesis of compounds composed of metallic and nonmetal elements, including metal oxides and phosphides. Thus, electrochemical techniques are poised to offer potential high-performance nanoscale metallic catalysts along with profound insights into the crystal growth mechanism. Nevertheless, a critical challenge hindering the application of electrochemical methods lies in bridging the considerable gap between catalysts and the preparation of electrode-level catalyst layers. The electrochemical signal proves highly sensitive to variations in the reaction environment, and discrepancies in electrode and system properties can lead to distinct electrochemical responses. Consequently, thorough investigations are imperative to address these issues.

With the advancement of science and technology, traditional energy sources such as oil and coal have been extensively depleted, leading to the emission of greenhouse gases like CO₂. Consequently, issues such as energy scarcity and drastic environmental changes have emerged as pressing concerns that threaten human survival and development. Photocatalysis offers a promising solution by harnessing solar energy for chemical energy conversion, yielding clean and sustainable products. It is widely regarded as an emerging approach to address the energy crisis and environmental challenges. To achieve high-efficiency photocatalytic reactions, the selection of appropriate catalysts and co-catalysts plays a pivotal role. However, conventional photocatalysts such as TiO₂, CdS, and g-C₃N₄ suffer from inherent limitations, including high charge recombination rates, low light utilization efficiency, poor stability, and sluggish charge transfer kinetics, which hinder the enhancement of photocatalytic efficiency. In this context, two-dimensional (2D) materials known as MXenes have gained prominence. These materials exhibit unique structural flexibility, diverse elemental compositions, superior conductivity, excellent carrier mobility, and abundant active sites, making them valuable co-catalysts in photocatalysis. MXenes accelerate interfacial charge transfer kinetics and mitigate charge recombination, enhancing the overall photocatalytic performance. This review provides a comprehensive overview of various methods employed to prepare high-quality MXenes under different conditions, such as water solution etching, water-free etching, and other physical methods. It also explores diverse strategies for constructing MXene-based composite photocatalytic systems, including in situ growth synthesis, in situ oxidation synthesis, and electrostatic self-assembly. Additionally, the review discusses various MXenes-based photosystems, such as MXene/TiO₂, MXene/CdS, MXene/g-C₃N₄, MXene/WO₃, and BiOBr/MXene/MMTex, and their applications in photocatalytic processes, including hydrogen production, CO₂ reduction, environmental remediation, nitrogen fixation, and sterilization. The critical role of MXenes as reduction co-catalysts in these photoredox catalysis reactions is thoroughly examined, along with an elucidation of the relationship between MXene electronic structure and charge transfer characteristics. Furthermore, the review addresses the challenges related to the stability of MXenes in photocatalytic reactions and offers insights into potential strategies to mitigate this issue. Finally, the development prospects and future challenges of MXene-based composites in the field of photocatalysis are presented, taking into consideration the inherent limitations of MXenes and the requirements for industrialization. It is expected that this review will provide valuable insights into the physicochemical properties of MXenes and inspire innovative approaches to the rational design of diverse MXene-based photosystems for heterogeneous photocatalysis across various applications.

Bulk-heterojunctions (BHJ) Organic solar cells (OSCs) have garnered considerable attention in the past two decades due to their advantages, including mechanical flexibility, lightweight, low-cost solution-processability, and semitransparency. The recent years have witnessed rapid progress in the realm of OSCs centered around non-fullerene acceptors (NFAs) thanks to the distinct merits of NFAs's stronger and broader absorption, highly adjustable energy levels, and easily modification of molecular structures. The power conversion efficiency (PCE) of single-junction OSCs has now reached high values of over 19%, which brings them closer to the threshold for commercial viability. This increase in PCE is attributed to advancements in active layer materials, device engineering, and a deeper comprehension of device physics. Nevertheless, achieving high PCE is not the only requirement for commercialization, while the stability of the devices is equally pivotal. The photovoltaic performance degradation of BHJ OSCs devices has been widely observed, however, the research on the stability of NFA-based OSCs has received less attention than efforts directed towards improving PCE through novel material development. The instability of NFA-OSCs has been one of the key obstacles limiting their transition to commercial applications. Various factors, encompassing both external and intrinsic variables, influence their stability. External factors, such as light, heat, water, and stress, exert significant impact on the stability of OSCs. Effective encapsulation can protect the devices from contact with oxygen and water, curtailing degradation. Encapsulated OSCs have demonstrated encouraging operational lifetimes of several years under certain degradation environments, in stark contrast to unencapsulated OSCs which often succumb to rapid degradation, losing their performance within a matter of minutes to days. Intrinsic degradation processes within NFA-OSCs involve material stability, morphology stability of BHJ and interface stability. The degradation of NFA based cells was not fully investigated as has been done on the fullerene based OSCs. There remains a lack of concrete molecular design rules to enhance the stability of NFA based OSCs. Therefore, it is still highly needed to further understand the intrinsic degradation processes of NFA-OSCs and to find proper ways to suppress these degradation processes. Herein, in this context, we present a comprehensive review encompassing the intrinsic fundamentals of instability including photo-oxidation of NFAs, interlayer-induced degradation of NFAs and the blend film morphology. Furthermore, we summarize recent advancements in strategies aimed at enhancing the stability of NFA-OSCs. These include stable NFA molecular design, mitigation of interfacial chemical reactions, and implementation of ternary strategies. It is our aspiration that this concise review will serve as a valuable resource for researchers interested in stability considerations, providing a guiding framework for future endeavors in achieving both efficient and stable NFA-OSCs.

The social development model relying on coal, oil, natural gas, and other fossil fuels as the primary energy sources has not only hastened the depletion of non-renewable resources but also led to a continuous increase in atmospheric CO₂ concentration. As human society’s understanding of energy structures deepens and environmental consciousness grows, the pursuit of effective clean CO₂ capture and catalytic conversion technologies has become a research priority. This is essential for promoting adjustments to the energy mix and achieving global carbon neutrality through artificial carbon cycling. Among the various CO₂ capture and catalytic conversion technologies, electrochemical catalytic CO₂ reduction (CO₂RR) at ambient temperature and pressure holds promise for advancing artificial carbon cycling, carbon storage, and mitigating environmental degradation. This technology can be driven by intermittent renewable energy sources such as solar energy, wind energy, tidal power, geothermal energy, etc. Furthermore, using water as a clean proton source, a wide array of chemicals can be synthesized. While recent studies have made significant progress in CO₂RR within aqueous solutions, there remains untapped potential in generating other important small organic molecules like urea, amides, amines, derivatives, and even amino acids. These compounds are of great interest due to their widespread applications in fertilizers, chemical synthesis, pharmaceuticals, and the aerospace industry. The electrocatalytic synthesis of organonitrogen compounds through N-integrated CO₂RR (NCR) is considered crucial for improving the practical applications and offering a reference for biological small molecules. However, NCR involves multi-step electron and proton transfer processes, leading to current challenges, including slow kinetics and a complex reaction mechanism. In this review, we delve into the detailed reaction pathways and the rational design of catalysts for different NCR products, which are vital for developing highly efficient electrocatalysts. Although some progress has been made through various strategies, there are still challenges to overcome, limiting their large-scale practical applications. The discussion concludes by addressing these existing limitations and outlining potential avenues for future improvements. We hope that this feature article will be instrumental in the development of novel electrocatalysts for NCR.

With the development of modern society, the demand for energy is increasing. Consequently, the efficient utilization of renewable energy has become the primary concern in the energy sector. Secondary batteries can accomplish energy storage through efficient electrical/chemical energy conversion, thereby providing an effective solution for the utilization of renewable energy. Lithium-ion batteries have been the most widely used secondary battery systems, owing to their high energy densities and long lifetimes. Nevertheless, traditional inorganic cathode materials have recently encountered problems such as increasing manufacturing costs, lithium supply-chain constraints, and safety issues. Meanwhile, organic electrode materials (OEMs) have emerged as promising electrode candidates for secondary batteries owing to several advantages, such as their low costs, abundant resources, environmental friendliness, and structural designability. In recent decades, considerable efforts have been dedicated to OEM research. To date, commonly used OEMs include carbonyl polymers, conductive polymers, nitrile compounds, organic sulfides, organic free radical compounds, imine compounds, and Azo compounds. OEMs have been used in various metal ion battery systems, including lithium-, sodium-, aluminum-, zinc-, magnesium-, potassium-, and calcium-based batteries. However, the commercialization of OEMs still encounters several challenges, mainly owing to their low conductivity, high solubility, and low discharge potential. The low intrinsic conductivity of OEMs leads to difficulties in ion diffusion, while their high solubility in organic electrolytes inevitably reduces cyclic stability. Moreover, the low discharge potential of OEMs decreases energy density and rate performance. In view of the technical restrictions affecting OEMs, researchers have focused on modifications and optimizations of the structure, preparation strategies, and sizes of OEMs. In this paper, we review the development history and applications of OEMs and systemically summarize their classification, reaction mechanisms, and primary challenges. In addition, we thoroughly report on OEM modification strategies. By shaping their molecular structures, such as either by substituent introduction, conjugated structure formation, or small molecule polymerization, the solubility of OEMs can be reduced, and their discharge potential can be enhanced. The conductivity of OEMs can be improved significantly by combining them with conductive carbon materials. Nano-sized optimization and electrode–electrolyte coupling can also significantly improve their cycle stability and rate performance. Additionally, the electrochemical performance of OEMs can be improved by optimizing preparation processes and determining the best technological parameters. Finally, we envision future research paths of OEM modification, which could provide a future reference in OEM design and research.

Rapid population growth and the demand for energy, which is powered by unrestricted fossil fuel exploitation, have caused severe environmental problems. Thus, it is crucial to effectively exploit alternative clean energy sources. Solar energy, which is a sustainable renewable energy source, provides an effective strategy for mitigating the energy crisis and greenhouse effect without resulting in additional carbon emissions. The concept of converting carbon dioxide (CO₂) into synthetic fuels is a promising solution towards realizing a sustainable carbon-neutral economy. Photocatalysis is a favorable approach for CO₂ conversion, but it has limitations in terms of conversion rates, efficiency, and scalability. Therefore, the novel concept of photothermal catalysis has been proposed based on the photothermal effect of catalysts, which allows for the complete exploitation of the solar spectrum, especially infrared light that is typically wasted during photochemical catalysis. Photothermal catalysis, combining photochemical and photothermal effects, can effectively catalyze chemical reactions under mild conditions. Although various metal structures can serve as the light-absorbing and active centers for photothermal catalysis, they suffer from disadvantages such as insufficient light utilization, high cost, and poor stability. Recently, naturally abundant silicon has emerged as a prospective photothermal catalyst, especially silicon nanostructure arrays, which outperform other conventional silicon materials owing to their excellent light-harvesting ability and efficient catalytic performance. Compared with conventional photothermal catalysts, silicon nanostructure arrays have demonstrated unique catalytic performance advantages in the photothermal CO₂ reduction reaction. As a platform, silicon nanostructure arrays exhibit an excellent light-harvesting ability, high specific surface area, and versatile hybridization possibilities. This review discusses the fundamental concepts and principles related to the theory and applications of photothermal catalytic CO₂ conversion, the functionalities of silicon nanostructure arrays in conventional photothermal CO₂ catalytic reduction, and the recent developments in photothermal CO₂ catalysis using silicon nanostructure arrays. Ultimately, it provides a guide for the development direction of high-performance nanostructure arrays-based photothermal CO₂ catalysts.

Lithium-sulfur (Li-S) batteries have emerged as promising candidates for next-generation secondary power batteries given that they exhibit extremely high discharge specific capacity (1672 mAh·g^-1) when sulfur is used as the positive electrode. Despite the potential of Li-S batteries for commercial applications, two significant issues need to be addressed: the shuttle effect of dissolved high-order lithium polysulfides (Li₂S_n, 4 ≤ n ≤ 8) during charge/discharge processes and the slow redox kinetics of sulfur species. Fortunately, the introduction of electrochemical catalysis is an effective strategy to mitigate the above problems. In the context of electrochemical catalysis, in this paper we discuss the existence forms of polysulfides and draw clear conclusions. Specifically, in ether electrolyte systems, the dominant form of polysulfide is the neutral molecule, while a smaller proportion exists as anions and cations. In addition, we also propose the corresponding solutions for different forms of polysulfides. Unlike previous reports, we analyze the conversion mechanism of polysulfides from two perspectives: adsorption-catalysis and reactive intermediates. In terms of the strength of the interaction force between the substrate materials and polysulfides, adsorption-catalysis can be classified into physisorption-catalysis and chemisorption-catalysis. The differences between both types are analyzed and discussed in-depth. Additionally, the reactive intermediates are further classified into sulfur free radicals, thiosulfates, and organosulfur molecules based on different electrochemical reaction pathways. The mechanisms involved in the reactions of these intermediates are subsequently analyzed in detail. We also evaluate different strategies and list the types of catalysts that may correspond to each mechanism. Finally, the quantitative evaluation method of catalytic performance is also summarized, which paves a new way for the design of high-efficiency electrocatalysts in Li-S batteries. The nucleation transformation ratio (NTR) is a quantitative measure we developed to assess the catalytic properties of materials. When the reaction is ideal, the NTR should be equal to 3. A calculated NTR close to 3 indicates that the reaction from Li₂S₆ to Li₂S₄ occurs rapidly, suggesting that the material is highly catalytic to polysulfide nucleation. This quantitative approach enables researchers to determine the adsorption and catalytic effects of cathode materials on polysulfides, allowing the study of lithium-sulfur battery cathode materials to move from qualitative description to quantitative evaluation with specific factors. As a result, we can move from a qualitative description of lithium-sulfur battery cathode materials to their quantitative evaluation.

Electrocatalytic water splitting driven by renewable energy is a potential approach to obtain green hydrogen. However, the relatively high overpotential of anodic oxygen evolution reaction (OER) is one of the main obstacles hindering the widespread popularity of water electrocatalysis technology. To this end, electrochemical hydrogen-evolution coupled with the oxidation of biomass derived platforms, such as replacing OER with thermodynamically favorable 5-hydroxymethylfurfural (HMF) oxidation reaction (HMFOR), provides an efficient strategy to lower energy utilization and co-producing valuable organic oxygenates. For instance, 2,5-furandicarboxylic acid (FDCA) is emerging as an important and value-added industrial chemical obtained from HMFOR, which can be used as the monomer of various sustainable bioplastics (e.g., polyesters, polyamides). Great efforts have been devoted to this arena on electrocatalyst engineering for better activity and product selectivity. However, less work has focused on the process scalability of HMFOR to FDCA. Here, we report a simple hydrothermal method to fabricate an array-structured nickel-vanadium layered double hydroxides (NiV-LDH) growth on nickel foam matrix, demonstrating large-sized (6 cm × 10 cm) synthesis of self-supported electrode. The as-prepared material is active and efficient for HMFOR, achieving 100 mA∙cm⁻² of current density at 1.52 V vs. RHE (reversible hydrogen electrode) with 94.6% of Faradaic efficiency and 89.1% of yield to FDCA. Compared to traditional water splitting, replacing OER with HMFOR improves the counterpart hydrogen production rate by two-times. As proof-of-concept, we demonstrate the continuous and scalable HMFOR using a low-cost and membrane-free flow reactor system with electrode area of 49.5 cm². Under a constant current of 10 A, this system achieves high HMF single-pass conversion (94.8%), high FDCA concentration (~186.8 mmol∙L⁻¹), and high FDCA selectivity (98.5%) using 200 mmol∙L⁻¹ of HMF feedstock at a flow rate of 3.62 mL∙min⁻¹. Finally, gram-scale FDCA (119.5 g) can be obtained with hydrogen production using water electrolysis technology. This work highlights that catalyst design and system engineering should be coupled in the future rather than continuing in parallel directions.

Catalytic oxidation is a commonly employed technology in the industry for removing volatile organic compounds (VOCs) due to its exceptional efficiency under mild operating conditions. Although supported Pt-based nano-catalysts are recognized widely as one of the most promising and extensively used industrial catalysts for VOC abatement, their practical application, and development are restricted by their exorbitant cost. Single-atom catalyst (SAC) with maximized metal utilization and exclusive electronic character has been explored extensively in various catalytic reactions. However, Pt SAC is usually deemed to be inactive in hydrocarbon oxidation reactions in thermal catalysis, compared with its nanoparticle counterpart. Here, we demonstrate that the WO₃-TiO₂ supported Pt SAC (Pt₁/WO₃-TiO₂) exhibits much higher activities than the corresponding nanoparticle catalyst (Pt_NP/WO₃-TiO₂) in photo-thermo catalytic oxidation of C₃H₈ and C₃H₆, which represent different kinds of typical VOCs. A key finding is that the activities of Pt₁/WO₃-TiO₂ and Pt_NP/WO₃-TiO₂ can be accelerated in photo-thermo catalytic C₃H₈ oxidation by overcoming oxygen poisoning. Upon the light irradiation, the apparent active energy (E_a) of the Pt₁/WO₃-TiO₂ and Pt_NP/WO₃-TiO₂ decline from 116 to 60 kJ·mol⁻¹ and from 103 to 30 kJ·mol⁻¹, respectively, substantiating their effectiveness in photo-thermo catalysis. Notably, a substantially higher reaction rate of 3792 μmol∙g_Pt⁻¹∙s⁻¹ on the Pt₁/WO₃-TiO₂ is achieved, which should be a benchmark for C₃H₈ oxidation. More intriguingly, photo-thermo catalytic C₃H₆ oxidation on the Pt_NP/WO₃-TiO₂ is prohibited due to the strong adsorption-induced C₃H₆ poisoning on the Pt nanoparticles, for which the E_a of the Pt_NP/WO₃-TiO₂ catalyst for C₃H₆ oxidation is maintained at approximately 55 kJ·mol⁻¹, regardless of the light irradiation. In comparison, the C₃H₆ poisoning on the Pt₁/WO₃-TiO₂ can be mitigated by light illumination, where the E_a of the Pt₁/WO₃-TiO₂ catalyst for C₃H₆ oxidation dramatically reduced from 49 to 16 kJ·mol⁻¹, signifying that the high energy barrier of C₃H₆ oxidation can be mediated by the light. Profiting from the apt affinity between C₃H₆ and Pt single atoms, the photogenerated electrons accumulated on the Pt single atoms produce repulsive force towards the electron-rich C₃H₆ molecules, which is conducive to the C₃H₆ desorption from the Pt₁/WO₃-TiO₂. Therefore, the Pt₁/WO₃-TiO₂ exhibits enhanced activity in photo-thermo catalytic C₃H₆ oxidation. This study exemplifies that the advantages of SAC are not only saving the consumption of precious metals but also discovering new catalytic reactions on the account of the specific electronic characteristic.

Solid-state lithium batteries (SSLBs) have the potential to further boost the energy density of Li-ion batteries and improve their safety by facilitating the use of Li-metal anodes and limiting flammability, respectively. Solid electrolytes, as key SSLB materials, significantly impact battery performance, among which composite polymer/garnet electrolytes are promising materials for manufacturing SSLBs on a large scale, owing to polymer electrolyte processing ease in combination with the thermal stabilities and high ionic conductivities of garnet electrolytes, both of which are beneficial. Uniformly dispersing garnet particles in the polymer matrix is important for ensuring a highly ionically conductive composite polymer electrolyte. However, high nanoparticle surface energies and incompatible organic–inorganic interfaces lead to garnet particle agglomeration in the polymer matrix and a poorly ionically conductive composite electrolyte. With the aim of promoting Li_6.4La₃Zr_1.4Ta_0.6O₁₂ (LLZTO) particle dispersion in both solvents and polymer matrices, in this study, we introduced the 3-glycidyloxypropyl trimethoxy silane (GPTMS) coupling agent onto the LLZTO surface. A 5-nm-thick GPTMS shell was constructed on each LLZTO nanoparticle by covalently bonding GPTMS molecules on the surface of the nanoparticle. The lipophilic epoxy group in GPTMS enables the uniform dispersion of GPTMS-modified LLZTO nanoparticles (LLZTO@GPTMS) in organic solvents, such as acetonitrile, N-methylpyrrolidone, and N,N-dimethylformamide. Particle-size-distribution experiments reveal that LLZTO-nanoparticle dispersity is positively correlated with solvent polarity. Well-dispersed LLZTO suspensions led to superior polyethylene-oxide-based (PEO-based) composite polymer electrolyte ionic conductivities of 2.31 × 10^-4 S·cm^-1 at 30 °C. Both symmetric lithium batteries and SSLBs that use LiFePO₄ (LFP) cathodes, lithium-metal anodes, and the optimal PEO: LLZTO@GPTMS electrolyte exhibited prolonged cycling lives. Moreover, the polyethylene separator was homogeneously coated with LLZTO nanoparticles following GPTMS modification. LFP|Li batteries with LLZTO@GPTMS-coated PE separators exhibited better cycling stabilities than those of batteries with unmodified LLZTO/PE. This study demonstrated that GPTMS effectively improves LLZTO-nanoparticle dispersibility in both organic solvents and polymer matrices, which is also instructive for other organic–inorganic composite systems.

Transforming the current structure of energy production and consumption, which currently excessively relies on fossil fuels, into a more efficient utilization of renewable energy, is an effective solution for addressing the energy crisis and achieving carbon neutrality. Biomass represents one of the most promising sources of renewable energy, capable of replacing fossil fuels and yielding valuable organic compounds. In recent years, the vigorous utilization of biomass energy sources has become an inevitable trend. The conventional thermochemical catalysis method used for biomass conversion often requires harsh conditions, such as high temperatures and pressures, and even external sources of hydrogen or oxygen. In comparison, the electrocatalytic conversion of organic molecules derived from biomass offers a greener and more efficient strategy for producing high-value chemicals under relatively mild conditions. Particularly, the cleavage of carbon chains through C―C bond cleavage is crucial in transforming biomass-derived molecules into short-chain chemicals of high value. Numerous studies have demonstrated that transition metal (TM) electrocatalysts play a critical role in the C―C bond cleavage of organic compounds, owing to their rich 3d electron structure and unique e_g orbitals that enhance the covalence of transition metal-oxygen bonds. Moreover, the coordination environments and electronic structures of TM electrocatalysts can influence the selectivity of the products. Undoubtedly, well-defined active sites and reaction pathways facilitate a comprehensive understanding of the structure-activity relationship between catalyst structure and reaction activity. However, the electrocatalytic cleavage of C―C bonds for biomass upgrading on TM electrocatalysts is still in its initial stages, and the reaction mechanism and catalytic processes remain unclear. Therefore, there is a need to systematically comprehend the role of electrocatalysts at the atomic level during the C―C bond cleavage process. This review begins by providing an overview of the extensively studied TM electrocatalysts that mediate C―C bond cleavage reactions of organic molecules derived from biomass, including glycerol, cyclohexanol, lignin, and furfural. Several representative examples and corresponding reaction pathways are presented. Subsequently, we systematically review the reaction mechanisms underlying the catalytic C―C bond cleavage by transition metal compounds, elucidate interfacial behaviors, and establish a structure-activity relationship between the structure of TM electrocatalysts and cleavage reaction activity. Finally, we provide a brief summary of the content covered and highlight the challenges and prospects in exploring C―C bond cleavage on TM electrocatalysts. It is anticipated that this work will serve as a guide for the controlled conversion of biomass and the rational design of TM electrocatalysts for C―C bond cleavage.

In recent years, Cu-based multi-metallic nanocrystals with controlled elemental distributions have been extensively studied for potential applications as electrocatalysts for CO₂ reduction reaction (CO₂RR). Modifying Cu electrocatalysts with secondary or additional metals offers a viable approach to manipulate the overall d-band structure which would cause the shift in the d-band center. Such manipulation can affect the surface affinity of Cu towards key intermediates and thus the following catalytic pathway. Apart from endeavors to adjust the electronic structure, morphological engineering provides effective avenues to enhance the electrocatalytic performance of CO₂RR. In contrast to quasi-spherical particles with irregular shapes, a 3D-assembled porous structure utilizing 2D nanosheets as building blocks offers advantages such as maximizing surface atom exposure and creating numerous diffusion channels and reactive sites for intermediates formed during catalysis. Yet, it is technique challenging to construct such type of nano-architecture via a rationally-design synthetic routes and traditional stepwise self-assembling strategy is time-consuming and lack of versatile control over the structural parameters of resulting products. Therefore, it holds significant value to develop a synthesis method capable of yielding high-purity formations of unique nanostructures. These structures should possess accurately controlled elemental compositions and electronic configurations, and establish a potential correlation between structural benefits and enhanced electrochemical performance in CO₂RR. Herein, we report the controlled synthesis of palladium-copper-silver (Pd-Cu-Ag) nanocrystals with rationally-designed two-dimensional (2D)-three-dimensional (3D) hybrid architectures and validated with the promising use for electrochemical CO₂ reduction (CO₂RR). The synthetic procedure includes the conversion of Au@Cu_xO nanospheres into CuAg hierarchical nanoflowers (HNFs), as directed by the capping agent octadecyltrimethyl ammonium chloride. Interestingly, the nanosheets are formed in situ as the building block. Following galvanic replacement reaction between CuAg HNFs and Na₂PdCl₄ removes Ag and Cu, introduces zero-valent Pd, and creates abundant pores on the nanosheets. These CuAg-based products are tested as CO₂RR electrocatalysts, in which the Pd_0.7Cu_40.0Ag_59.7 PHNFs displayed the optimized performance in terms of C₂₊ products selectivity (69.5%) and C₂₊ partial current density (-349.1 mA·cm^-2). As revealed by density functional theory (DFT) simulations, PdAgCu surface has distinct electronic property, which lower the reaction barrier for C-C coupling, protruding the exceptional advantage of the Pd doping towards CuAg electrocatalysts for CO₂ reduction. The present study offers a straightforward approach to fabricate hierarchical multi-metallic nanostructures with the porous nanosheet as building block, and validates its structural advantage in electrocatalysis, shedding light on the rational design of efficient CO₂RR catalyst.

The conversion of renewable solar energy into chemical energy is an important topic in research. Recently, bismuth chromate (Bi₂CrO₆) has attracted attention in photocatalytic research, particularly for its potential applications in pollutant degradation and water splitting. This layered metal oxide exhibits a narrow optical band gap of approximately 1.9 eV and can utilize most of visible light in the solar spectrum. However, the photocatalytic activity of Bi₂CrO₆ is relatively low, and its poor charge separation properties restrict its practical applications. Herein, we report a microwave-assisted hydrothermal method for the fabrication of Bi₂CrO₆ crystals with high crystallinity and uniform morphology. Compared with the conventional preparations, microwave irradiation induces rapid volumetric heating and greatly accelerates nucleation and growth reactions, forming Bi₂CrO₆ crystals within minutes. Multiple characterization methods, including X-ray diffraction, Raman scattering, and scanning electron microscopy, were employed to examine the crystallinity and morphologies of the samples. Microwave-assisted synthesized Bi₂CrO₆ crystals showed better water oxidation activity in photocatalytic and photoelectrochemical tests than the conventional samples. Oxygen evolution rates were boosted 7.2 and 3.1 times using AgNO₃ and Fe(NO₃)₃ as electron acceptors, respectively. Further investigations showed that microwave-assisted Bi₂CrO₆ crystals exhibited improved photogenerated charge separation. The average lifetime of photogenerated carriers, calculated from time-resolved photoluminescence results, also showed an increase. Furthermore, using photodeposition of metals and oxides as probes, the spatial separation of photogenerated electrons and holes was demonstrated to take place between {001} top and side facets of the Bi₂CrO₆ crystal samples. Loading reduction and oxidation cocatalysts onto different facets significantly enhanced the photocatalytic activities. These results enforce the promise of microwave-assisted Bi₂CrO₆ crystal synthesis for photocatalytic water-splitting applications and present a solution for efficient solar-energy conversion.

Formamidinium lead iodide (FAPbI₃) perovskite solar cells (PSCs) have attracted significant attention owing to their outstanding optoelectronic properties, but long-term device stability is still a crucial issue related to FAPbI₃ PSCs. FAPbI₃ undergoes phase transition from black perovskite phase to yellow non-perovskite phase at room temperature, and moisture triggers this phase transition. One of the most widely used methods to improve the stability of PSCs is interface engineering. Being green functional solvents, ionic liquids (ILs) have been regarded as potential alternatives to toxic interface modifiers, thereby increasing their commercial viability and accelerating their adoption in the renewable energy market. In this study, an IL, 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIM[BF₄]) was used to modify the interface between the electron transport layer and perovskite layer due to its low volatility, low toxicity, high conductivity, and high thermal stability. The introduction of IL not only reduces interface defects but also improves perovskite film quality. Density functional theory (DFT) calculations show that there is a strong interface interaction between the IL and perovskite surface that is beneficial to decrease the density of defect states of the perovskite surface and stabilize the perovskite lattice. Apart from the defects in the perovskite film, solution-processed SnO₂ also suffers from surface imperfections. Defects on the SnO₂ surface generate defect states, which cause band alignment issues and stability issues. DFT calculations show that the surface gap states with IL are smaller than those without IL. Such weakened surface gap states indicate reduced carrier recombination at the surface region, which improves the device performance. Consequently, we achieved a power conversion efficiency exceeding 22% for the IL-modified FAPbI₃ PSCs (control~21%). After storing for over 1800 h in a dry box (relative humidity (RH) ~20%), the champion device retained ~90% of its initial efficiency, while the control devices degraded into non-perovskite yellow hexagonal phase (δ-FAPbI₃).

Hydrogen fuel has long been considered a promising and practical alternative to conventional fossil fuels for shaping the future of our energy landscape. The electrocatalytic water-splitting technique, a sustainable and eco-friendly technology, provides a viable solution for efficiently and abundantly producing high-purity hydrogen on a large scale. However, practical applications of this technology require continuous improvement in the reaction kinetics for the hydrogen evolution reaction (HER) at the anode and the oxygen evolution reaction (OER) at the cathode. Additionally, ongoing optimization of the catalyst’s catalytic activity and structural stability is crucial for the practical implementation of this technology. The selection of suitable catalysts is of paramount importance in water splitting. As a result, two-dimensional (2D) nanomaterials have become a focal point in water electrolysis due to their unique physicochemical properties and abundant active sites. The atomic thinness of 2D materials makes their electronic structure easily adjustable, allowing for the precise control of electrocatalytic performance through morphological modifications, defect engineering, phase transitions, cocatalyst deposition, and element doping. However, the complex system structure design and the potentially mutual interference of various chemical components could hinder further improvements in hydrogen evolution performance. Fortunately, the distinctive physicochemical characteristics of 2D materials can synergize with external physical fields, leading to enhanced electrocatalytic performance through distinct effects. For example, magnetic fields, electric fields, and light fields can induce thermal effects, effectively reducing charge transfer resistance and bubble coverage on the catalyst surface. Strain can regulate the d-band center, thus controlling adsorption energy. Moreover, the superposition of multiple physical fields and the multiple effects of a single physical field offer enormous potential for enhancing electrocatalytic performance. It is evident that the regulation of electrocatalytic performance through physical fields holds significant untapped potential. Consequently, the roles and mechanisms of external physical field assistance in HER and OER have garnered increasing attention. External fields such as electric fields, magnetic fields, strain, light, temperature, and ultrasound can be applied to synthesis and electrocatalysis. This paper first provides a summary of research on the synthesis of physical field-assisted electrolytic water catalysts. It then classifies studies on field-assisted HER and OER based on different mechanisms. Finally, it outlines the key challenges and prospects in this rapidly evolving research field.

Current commercialized lithium ion batteries generally suffer from safety issues due to using flammable organic liquid electrolytes. All-solid-state lithium batteries employing solid electrolytes instead of organic liquid electrolytes and separators possess the advantages of both good safety and high energy density, which is expected to be the most promising energy storage devices for the next generation electric vehicles and smart grid. Sulfide solid electrolytes are regarded as crucial components for all-solid-state rechargeable batteries for the merits of their high room temperature ionic conductivities that approaches or exceeds liquid organic electrolytes and excellent mechanical ductility. The preparation methods of sulfide solid electrolytes are mainly divided into three categories, i.e. solid-state sintering, ball milling and liquid-phase method. However, solid-state sintering and ball milling are time-consuming accompanied by high energy consumption. At the same time, the synthesized electrolyte particles are large in size, which seriously limits the practical application of sulfide electrolytes. In contrast, the liquid-phase method, using organic solvents as the medium, can synthesize sulfide solid electrolytes with controlled particle sizes, which is a simple and time-saving process and more suitable for large-scale production. In this review, we begin by introducing the crystal structures and ion transport mechanisms of major sulfide electrolytes including Li₂S-P₂S₅ binary sulfide solid electrolytes, Li₁₀GeP₂S₁₂ and Li₆PS₅X (X = Cl, Br, I) ternary systems, and summarize the progress of sulfide solid electrolytes prepared by liquid phase method in recent years. Based on the solubility state of the reagents in the solvent, the liquid-phase synthesis of sulfide electrolytes can be categorized into suspension type, solution type and mixed type, and their reaction mechanisms are discussed separately. Subsequently, we summarize the effect of solvents on the properties of liquid-phase synthesized sulfide electrolytes, such as purity, morphology, crystallinity and ionic conductivity. In addition, the application of liquid-phase synthesized sulfide solid electrolytes for all-solid-state lithium batteries is presented from six aspects: sulfide electrolytes coated on active materials, electrolyte-active material composites, electrolyte injection into porous electrodes, interfacial modification at solid-solid contact triple-interfaces within electrode layers, electrolyte elemental doping and electrolyte film preparation, which demonstrates the superior scalability of the liquid-phase method and the diverse application prospects. Finally, according to the current research status of the sulfide solid electrolytes synthesized by liquid phase method, the advantages and limitations of the liquid phase synthesis of sulfide solid electrolytes are also analyzed, providing the development direction for the liquid phase synthesized sulfide solid electrolyte for all-solid-state lithium batteries in future.

The electrochemical carbon dioxide reduction reaction (eCO₂RR) can convert CO₂ into valuable chemicals, achieving a carbon cycle. Copper-based catalysts have demonstrated a unique ability to produce C₂₊ products in eCO₂RR, which is often limited by the scaling relationship of the reaction intermediates, complex reaction mechanism and competitive H₂ evolution. Organic functionalization is a promising strategy for regulating the activity and selectivity of eCO₂RR toward C₂₊ products. However, the mechanism behind such regulation of eCO₂RR, especially at the molecular level, remains elusive. In this study, Cu nanoparticles were prepared and functionalized with a set of amine derivatives, including hexadecylamine (HDA), N-methylhexadecylamine (N-MHDA), hexadecyldimethylamine (HDDMA), and palmitamide (PMM). The impact of the molecular structure of the amine surfactants on the selectivity and activity toward eCO₂RR was systematically explored through both experiments and theoretical calculations. X-ray photoelectron spectroscopy and density functional theory calculations revealed that HDA functionalization of the Cu catalyst surface resulted in negative charge transfer from amine molecules to Cu. ECO₂RR was examined in a 1.0 mol∙L⁻¹ KOH aqueous electrolyte. HDA functionalization of the Cu catalyst achieved the highest Faradaic efficiency (FE) of 73.5% for C₂ products and 46.4% for C₂H₄, respectively. It also provided the highest C₂ partial current density of 131.4 mA∙cm⁻² at −0.9 V vs. reversible hydrogen electrode (RHE) among these amine derivatives functionalized Cu catalysts. In contrast, the highest FE and partial current density for C₂ products achieved with pristine Cu catalysts were only 27.0% and 50.5 mA·cm⁻², respectively. Theoretical studies demonstrated that hydrogen bonding interactions of HDA with CO₂ and eCO₂RR intermediates enriched CO₂, CO, and other intermediates, lowered the kinetic energy barrier of CO―CHO coupling and thereby promoted eCO₂RR to C₂ products. Replacing the H atoms of the amine group with methyl groups in N-MHDA and HDDMA resulted in dominant hydrogen evolution reaction (HER) in eCO₂RR. PMM bonding with the Cu surface through a Cu―O bond, instead of Cu―N bonding as in HDA, N-MHDA and HDDMA, resulted in preferred ethanol production. In situ Raman spectroscopy indicated CO adsorption on Cu at atop sites for HDA-capped Cu catalysts, instead of bridge site CO adsorption on clean Cu surfaces, possibly due to the enriched CO in the former case. HDA also increased the local pH relative to pristine Cu catalysts. The Cu-HDA-based rechargeable Zn-CO₂ battery exhibited a superior maximum power density of 6.48 mW∙cm^–2 at a discharge current density of 16 mA∙cm^–2 and remarkable rechargeable durability for 60 h, outperforming most of the reported catalysts in the literature. This work enhances CO₂-C₂ conversion by tuning the eCO₂RR activity and selectivity of Cu-based materials, unravels the reaction mechanism at the molecular level, and provides new insights for promoting C₂ products in eCO₂RR through surface functionalization with organic molecules.

Nucleophile oxidation reaction (NOR) is emerging as a significant approach for the sustainable production of value-added chemicals. Among the various types, electrocatalytic glycerol oxidation reaction (GOR) stands out as a crucial method for producing C₁ to C₃ chemicals including formic acid (FA). Non-noble-metal-based (oxy)hydroxides have found extensive use in GOR, yet achieving industrially-demanded current densities (> 300 mA·cm^-2) at moderate potentials remains a challenge. It is well documented that GOR catalyzed by (oxy)hydroxides follows an indirect oxidation mechanism. Specifically, the nucleophile, glycerol, undergoes oxidation by the electrogenerated oxyhydroxides with electrophilic adsorption oxygen. Therefore, comprehending the evolution of the electrocatalyst in GOR is critically important. In this paper, we have developed molybdenum-doped nickel oxyhydroxides (Mo-NiOOH) through cyclic voltammetry (CV) activation of nickel molybdate (NiMoO₄). We demonstrated that Mo species leach from NiMoO₄, and the resulting Mo-NiOOH retains the nanosheet array morphology of NiMoO₄. We subjected the freshly prepared Mo-NiOOH to systematic characterizations employing techniques such as scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) mapping, Raman spectroscopy, inductively coupled plasma-mass spectrometry (ICP-MS), and X-ray photoelectron spectroscopy (XPS). The above structural characterizations confirm that Mo-NiOOH inherits the nanosheet array morphology of the NiMoO₄ precursor with reduced Mo content, thereby indicating the phase reconstruction from oxides to oxyhydroxides post CV activation. Furthermore, the Ni³⁺/Ni²⁺ ratio in Mo-NiOOH surpasses that in NiOOH derived from CV activation of Ni(OH)₂. Mo-NiOOH exhibits elevated electrochemically active surface areas (ECSAs) and a higher Ni³⁺/Ni²⁺ ratio compared to NiOOH obtained through CV activation of Ni(OH)₂, facilitating the Mo-NiOOH exhibits higher ratio of Ni³⁺/Ni²⁺, higher electrochemically active surface areas (ECSAs) than NiOOH, and facilitated oxidation of Ni²⁺ to Ni³⁺. Consequently, Mo-NiOOH requires a lower applied potential than NiOOH (1.51 V versus 1.84 V vs. reversible hydrogen electrode (RHE)) to achieve a high current density (400 mA·cm^-2). Additionally, Mo-NiOOH demonstrates higher Faradaic efficiency towards formate (FE_formate) in contrast to NiOOH (84.7% versus 59.6%), indicating enhanced carbon-carbon (C―C) bond cleavage due to Mo doping. Multi-potential step (STEP) experiments indicate that GOR catalyzed by NiOOH and Mo-NiOOH follows a similar indirect oxidation mechanism mediated by oxyhydroxides. Operando electrochemical impedance spectroscopy (EIS) and in situ Raman spectroscopy confirmed that Mo doping in NiOOH accelerates GOR kinetics and the oxidation of Ni²⁺ to Ni³⁺, contributing to the higher activity and formate selectivity of Mo-NiOOH than NiOOH. The strategy of surface modulation of oxyhydroxides through leaching of soluble anions offers guidelines for the rational design of high-performance NOR electrocatalysts.

Capacitive deionization (CDI) technology is considered to be an emerging water treatment technology in the 21st century, owing to its low energy consumption, absence of secondary pollution, and straightforward operation. The advancement of basic theory and computer science has facilitated the use of multi-angle numerical simulations for CDI. However, due to errors in experimental methods, a direct understanding of mechanisms such as the kinetic characteristics of ion diffusion inside electrode materials, structural evolution during charging and discharging, and the intrinsic connection between potentials and structures is lacking. Existing experimental methods fall short of providing clear theoretical explanations for these phenomena. In contrast, numerical simulations offer a better comprehension of the chemical and electrochemical evolution in CDI. Beyond electrode materials, the device configuration of CDI significantly impacts its performance. Utilizing numerical simulations to study the optimal device configuration is expected to enhance economic efficiency and promote the practical application of CDI. While current reviews of CDI focus primarily on electrode materials and device configurations, there is a dearth of comprehensive reviews on cutting-edge numerical simulation research in the CDI field. This review commences with the earliest continuous-scale model used to describe the dynamic process of CDI. It systematically categorizes multi-angle numerical simulations in CDI, summarizes the strengths and weaknesses of different numerical simulation methods, and anticipates future development directions. Continuous-scale models accurately characterize the ion dynamics of CDI, determining rate and process constraints. Pore-scale models analyze the microstructure of porous media, obviating the need for empirical formulas to preset transport parameters for continuous-scale models. Researchers have introduced molecular dynamics simulation and density functional theory into CDI research, effectively analyzing the influence of structural features at the molecular/atomic level of electrode materials on the CDI system. This aids researchers in enhancing the efficacy and ionic selectivity of CDI electrode materials through pore engineering, defect engineering, and electrochemical microcosmic modulation engineering. Finite element analysis guides improvements in ion diffusion and stability of electrode materials, while computational fluid dynamics provides references for designing high-performance CDI devices. Data-driven machine learning excels in handling nonlinear data and uncovering complex mechanisms of CDI water treatment processes, while digital twin technology can reduce operation and maintenance costs of CDI. Considering costs in practical applications, techno-economic analysis plays a pivotal role in promoting the practical application of CDI technology. This review, the first of its kind, provides an essential theoretical foundation and research ideas for the new paradigm of CDI research by summarizing the advantages and disadvantages of different numerical simulation methods and offering insights into cutting-edge perspectives in the field of CDI.

The storage of intermittent wind and solar electricity requires grid-level energy storage devices, and due to the abundance and wide distribution of Na resources, Na-ion batteries (NIBs) are much more cost-effective and have shown greater potential for large-scale energy storage than Li-ion batteries (LIBs). However, the lack of suitable cathode hinders the practical use of NIBs, so exploring suitable cathode materials that can maintain a balance between high energy density and cost-effectiveness is essential for NIBs. Ni-Mn based layered oxides are important cathode materials for NIBs, offering relatively high potential through the multi-electron redox reaction of Ni⁴⁺/Ni³⁺/Ni²⁺ as well as the low-cost and non-toxic nature of Mn⁴⁺. P2-Na_0.67[Ni_0.33Mn_0.67]O₂ was the first reported Ni-Mn based Na-ion battery cathode with a high capacity of ~160 mAh·g^-1 in the voltage range of 2.0-4.5 V, while irreversible P2-O2 phase transition above 4.1 V makes poor capacity retention and limits their applications. Moreover, a dilemma has emerged in that a costly element (Ni) is used for sodium-ion batteries, which is supposed to be low-cost. With the intensive research in recent years, introducing an appropriate amount of anionic redox can effectively improve energy density while simultaneously reducing the amount of high-cost transition metals, such as V, Co, and Ni. However, because of irreversible oxygen loss and Mn⁴⁺/Mn³⁺ redox activation, voltage decay is difficult to avoid for most of these anion-redox materials. In this research, we report a Li-substituted Na_x[Ni, Mn]O₂ cathode, the designed formula being Na_0.85[Li_0.2Ni_0.15Mn_0.65]O₂. This material shows a unique combination of both cationic redox (Ni⁴⁺/Ni³⁺/Ni²⁺) and anionic redox (O^2-/O₂^n-) during charge and discharge, showing a high capacity of ~150 mAh·g^-1 (10 mA·g^-1, 1.5-4.5 V) with only 0.15 Ni. With an optimized voltage range, the material shows a capacity of ~100 mAh·g^-1 and stable cycling performance (80% of initial capacity after 100 cycles at 10 mA·g^-1 within 2.5-4.25 V) and high-rate capability (the capacity of 500 mA·g^-1 is 80% of 10 mA·g^-1, 2.5-4.25 V). Moreover, we demonstrate an effective way to suppress the voltage decay and Mn reduction through Ni³⁺ as a redox barrier. Specifically, during the discharge process, the Mn⁴⁺/Mn³⁺ reduction process was replaced by the Ni³⁺/Ni²⁺ reduction process with higher redox potential in the layered oxides. In addition, the full Ni²⁺/Ni⁴⁺ redox can compensate for the partial oxygen redox loss in the subsequent cycles. We believe that introducing the anion redox through Li substitution and the use of Ni³⁺ as a redox barrier to suppress the voltage decay will provide a new way in the design of NIBs' cathode materials, with potential benefits such as higher energy density, lower cost, and longer cycle life.

The production of renewable fuels through water splitting via photocatalytic hydrogen production holds significant promise. Nonetheless, the sluggish kinetics of hydrogen evolution and the inadequate water adsorption on photocatalysts present notable challenges. In this study, we have devised a straightforward hydrothermal method to synthesize Bi₂O₃ (BO) derived from metal-organic frameworks (MOFs), loaded with flower-like ZnIn₂S₄ (ZIS). This approach substantially enhances water adsorption and surface catalytic reactions, resulting in a remarkable enhancement of photocatalytic activity. By employing triethanolamine (TEOA) as a sacrificial agent, the hydrogen evolution rate achieved with 15% (mass fraction) ZIS loading on BO reached an impressive value of 1610 μmol∙h⁻¹∙g⁻¹, marking a 6.34-fold increase compared to that observed for bare BO. Furthermore, through density functional theory (DFT) and ab initio molecular dynamics (AIMD) calculations, we have identified the reactions occurring at the ZIS/BO S-scheme heterojunction interface, including the identification of active sites for water adsorption and catalytic reactions. This study provides valuable insights into the development of high-performance composite photocatalytic materials with tailored electronic properties and wettability.

CO₂ hydrogenation is critical to producing high-value-added carbon-based chemicals and fuels to achieving both hydrogen energy storage and CO₂ utilization. Examples of CO₂ hydrogenation include methanation (Sabatier process) to produce methane, reverse water-gas shift reaction (RWGS) to generate CO, methanol synthesis for the methanol economy, and CO₂ direct Fischer-Tropsch (CO₂-FT) reaction to produce olefins. The precious metal catalysts used in these reactions are efficient but too expensive to be used on a large scale. Further, although some non-precious metal catalysts can be used for these hydrogenation reactions, they suffer from deactivation during long-term processes. Over the past few decades, molybdenum carbides, which are transition metal carbides (TMCs), have attracted significant attention owing to their low cost and similar catalytic performance to precious metal catalysts in CO₂ hydrogenation reactions. Recently, two-dimensional molybdenum carbide MXenes have shown impressive activity in CO₂ hydrogenation reactions. Owing to the presence of carbon, the MXene lattice is expanded; this leads to an increase in valence electrons and endows the two-dimensional molybdenum carbide-based catalyst with different properties than metallic Mo. The two-dimensional molybdenum carbide-based materials can be prepared by temperature-programmed carburization, selective etching, mechanical alloying synthesis, chemical vapor deposition, in situ thermal carburization, and solution-phase synthesis methods. Thus far, a host of studies have been performed on CO₂ conversion with molybdenum carbide-based materials, which show promising activity during CO₂ conversion and selectivity towards target products. Both α-MoC_1−x and β-MoC_y have shown outstanding thermocatalytic activity, product selectivity, and reaction stability during CO₂ hydrogenation to CO at 300-600 ℃. In addition, molybdenum carbide-based materials were also found to be an interesting catalyst for direct CO₂ Fischer-Tropsch synthesis. The application potential of the molybdenum carbide-based materials could be further tuned by changing the C/Mo ratio in the bulk molybdenum carbide, strengthening the interactions between molybdenum carbide and the supported metal, and tailoring the interface structure of the materials. However, the thermal catalytic CO₂ conversion based on molybdenum carbide-based materials is still in its infancy. This paper summarizes the progress toward molybdenum carbide catalysis of CO₂ hydrogenation process for producing high-value-added chemicals and fuels. Furthermore, the challenges and opportunities for molybdenum carbide materials as catalysts for CO₂ hydrogenation are discussed to provide insights for future development in this emerging field.

The escalating presence of pharmaceutical antibiotics in natural water poses an overwhelming threat to the sustainable development of society. Photocatalysis technology stands out as a promising and cutting-edge environmental purification alternative. C₃N₅, identified as a distinctive nonprecious nonmetal photocatalyst, holds potential for environmental protection. However, challenges persist originating from the sluggish photoreaction kinetics and severe photo-carrier reunion. Currently, the design of a special S-scheme photosystem proves to be a reliable strategy for obtaining outstanding photocatalysts. In this context, a plasmonic S-scheme photosystem involving Ag/Ag₃PO₄/C₃N₅ was developed through a feasible route. The compactly connected 0D/0D/2D Ag/Ag₃PO₄/C₃N₅ heterostructure, benefitting from the synergy between the plasmonic effect and the S-scheme junction, facilitates the efficient utilization of appreciably reinforced sunlight absorption, effective photo-carrier disassociation, and notable photoredox capacity. Consequently, this system generates ·OH and ·O₂^- effectively. Ag/Ag₃PO₄/C₃N₅ demonstrates a superb photocatalytic levofloxacin eradication rate of 0.0362 min^-1, marking a substantial advancement of 24.8, 1.1, and 0.7 folds compared to C₃N₅, Ag₃PO₄, and Ag₃PO₄/C₃N₅, respectively. Impressively, Ag/Ag₃PO₄/C₃N₅ delivers remarkable anti-interference performance and reusability. This achievement signifies a significant step toward developing potent C₃N₅-involved photosystems for environmental purification.

Currently, the world is at the intersection of the energy and computer revolutions. The electronic information industry, driven by the fields of 5G communication, smartphones, and new energy vehicles, is booming and has become an important pillar of the economic market. Multilayer ceramic capacitors (MLCC), which are passive electronic components with the highest market share, are one of the key products that require breakthroughs in key technologies in the basic electronic component industry, with wide applications in automotive electronics, power grid frequency modulation, aerospace, and other fields. With the trend of miniaturization and thin lamination, the thickness of the dielectric layer in the MLCC is decreasing continuously, whereas the electric field on the single dielectric layer is increasing significantly when the MLCC is applied under the same voltage, particularly for the ultrathin-layered MLCC served under medium/high voltage. Consequently, the reliability of MLCC has become a key product quality indicator. In this study, the deterioration mechanism of ultrathin-layer MLCC is systematically studied via accelerated aging tests, high-temperature impedance spectroscopy, and leakage current tests. During the accelerated aging test, the ceramic dielectrics degrades under the applied strict electric field and temperature, and the oxygen vacancies gradually migrate in grains and transgranularly, finally accumulating near the cathode, as observed by transmission electron microscopy. Consequently, a semiconducting layer with poor insulation performance near the cathode is formed, and the barrier height at the interface is reduced. Based on the results of the high-temperature impedance spectroscopy and leakage current test, the activation energy at the grain boundary and dielectric-electrode interface decreases, and the leakage current density increases significantly for the aged MLCC. The formation of an oxygen-vacancy-enriched semiconducting layer is a great threat to the reliability of MLCC, particularly under the trend of developing increasingly thinner dielectric layers. Therefore, inhibiting the migration and enrichment of oxygen vacancies is a top priority for ensuring the reliability of MLCC. To improve the reliability of ultrathin-layered MLCC, the oxygen vacancy concentration in ceramic dielectrics should be reduced, the activation energy required for its migration should be increased, and the Schottky barrier at the interface should be improved. All these results provide a powerful guide for the design of ultrathin-layered MLCC dielectric materials, which is expected to promote the upgrade iteration of high-end MLCC.

With the rapid growth of the economy, environmental and energy issues have become increasingly prominent. Solar energy, as a renewable and environmentally friendly energy source, has attracted the attention of many researchers. Maximizing the utilization of solar energy resources has become a hot research topic in the future. It is well known that photocatalytic technology can convert solar energy into chemical or electric energy, offering a solution to environmental pollution. Therefore, semiconductor photocatalytic technology has been recognized as one of the most eco-friendly approaches for addressing energy crises and environmental pollution. Bismuth-based semiconductor materials, have gained popularity in the field of photocatalysis due to their suitable band structure, wide range of variations, non-toxicity, and low cost. However, pure Bi-based photocatalysts suffer from high recombination efficiency of photoexcited electron-hole pairs, poor quantum yield and limited light absorption ability, resulting in low photocatalytic performance. To overcome these limitations, various strategies such as metal or nonmetal doping, metal deposition, construction of heterojunctions and inducing defect generation have been employed to enhance their photocatalytic performance. Among these strategies, element doping or metal deposition is considered an effective approach for adjusting the band structure and physicochemical properties of bismuth-based materials. This extends the range of light response and improves photocatalytic performance. This mini review aims to summarize the recent research progress in Bi-based materials modified by metal doping, nonmetal doping, metal and nonmetal co-doping, and metal deposition. It also explores their applications in different fields, including photocatalytic removal of pollutants and heavy metal ions, nitrogen reduction, carbon dioxide reduction, and photocatalytic antibacterial, etc. Regarding metal doping, we classify it into three categories: alkali or alkaline earth metals doping, transition metal doping, and rare earth metal doping, and provide a detailed introduction to the advantages and disadvantages of each type of doping. Nonmetallic doping is categorized into halogen and non-halogen doping, with a focus on the impact of nonmetallic doping on bismuth-based materials. Furthermore, we present a vertical comparison of the advantages of each element vertically. Co-doping, which combines the advantages of both metal and nonmetal elements, is briefly outlined in terms of recent research progress. In the case of metal deposition, we mainly discuss the impact on Bi based materials from two aspects: the Schottky barrier and the localized surface plasmon resonance (LSPR) effect. Finally, we also discuss the current challenges and prospects faced by metal or nonmetal modified Bi-based photocatalysts.

As for the accurate synthesis of high-performance electrochemical catalysts with good robustness, the rational design on atomic level is still a priority. Entropy, as one of the most significant thermodynamic parameters, measure the disorder of a system, which is a significant quantity for materials. The values are primarily determined by the crystal structure, magnetic moments and the atomic and electronic vibrations of the materials. According to the configurational entropy of the system, we usually divide the material into low entropy materials (LEMs) (∆S_mix < 1R), medium entropy materials (MEMs) (1R ≤ ∆S_mix ≥ 1.5R) and high entropy materials (HEMs) (∆S_mix > 1.5R), where R is the gas molar constant. HEMs are those that consist of five or more major elements of roughly equal proportion, in a highly uniform, random manner, which typically consist of one or two major elements compared to traditional materials. As the entropy value increases, the intrinsic physical, chemical and structural properties of the material change accordingly, resulting in special physicochemical properties (e.g., strength, electrical conductivity, corrosion resistance, etc.). Moreover, due to its multi-element combination, the HEMs can be precisely regulated by selecting different elements and their ratios according to the needs, which overcomes the limitations of the traditional catalysts in terms of relatively single component, structure and field of application. Importantly, the synergistic high entropy effect and multi-component arrangement at the atomic-level interface produced by the coexistence of different metal elements in HEMs can exert higher catalytic activity, selectivity and stability in different reactions. This has attracted a lot of attention from researchers, especially in the field of electrocatalysis. In this review systematically summarizes the fundamental concepts of high-entropy catalysts (HECs), synthetic approaches (“top-down” and “bottom-up”), and the structure-performance relationships of HEMs in different types of electrocatalytic processes, mainly including hydrogen evolution reaction (HER), oxygen evolution reaction (OER), oxygen reduction reaction (ORR), alcohol oxidation reaction (AOR), nitrogen reduction reaction (NRR), and carbon dioxide reduction reaction (CO₂RR) etc. Thus, the advantages and potential of high-performance electrocatalysts based on entropy increase engineering are illuminate. At the same time, it is summarized and discussed that HECs are currently facing problems and challenges such as complicated material rational design, complex preparation process, the mechanism of electrocatalytic processes in which multiple metal elements interact is ambiguous, and poor stability under extreme reaction conditions. Finally, the main problems and challenges facing the current HECs research. We look forward to the future design ideas, synthesis methods different research areas and industrial applications of HECs based on entropy enhancement engineering.

Hydrogen is an important zero-pollution green energy source with potential for alleviating environmental contamination and energy shortages. Hydrogen evolution via solar-energy-induced semiconducting water splitting is among the most environmentally friendly methods available to date. In this study, a metal–organic-framework-derived, Ni-decorated carbon nanotube (Ni-CNT) is used as a non-noble co-catalyst. This Ni-CNT is grown in situ on ZnIn₂S₄ nanosheets using a simple one-step oil bath strategy, wherein Ni nanoparticles are wrapped around the top and cross sections of the nanotubes, preventing their agglomeration. Notably, Ni-CNT/ZnIn₂S₄ heterostructures feature intimate contact interfaces that promote charge transfer, facilitating their use as efficient photocatalysts for hydrogen evolution. The 38Ni-CNT/ZnIn₂S₄ sample exhibits a high H₂ production rate (12267 μmol·h⁻¹·g⁻¹), with an apparent quantum efficiency (AQE) of 11.3% under 420 nm monochromatic light irradiation, which is nearly 6.4 times that of pure ZnIn₂S₄. The results of X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) corroborate the observations on Ni-CNT/ZnIn₂S₄ heterostructures. Electrochemical measurements reveal that the combination of the Ni-CNT and ZnIn₂S₄ facilitates the transfer of photogenerated electrons and effectively prevents rapid recombination of photocarriers, thus improving the hydrogen evolution performance of ZnIn₂S₄. Electron spin resonance (ESR) results further prove that co-catalyst Ni-CNTs are beneficial for prolonging the lifetimes of ZnIn₂S₄ photogenerated electrons, thereby achieving effective charge separation. A charge transfer pathway in the heterojunction interfaces is further explored and confirmed by density functional theory (DFT) calculations. The difference in the Fermi level energy (E_f) contributes to both charge migration and the generation of a built-in electronic field (BEF), indicating that the energy band of ZnIn₂S₄ bends downward, which is favorable for photogenerated electron flow from ZnIn₂S₄ to the Ni-CNT electron acceptor. The results of planar-averaged electron density difference analysis confirm that the hot electrons are transferred from Ni nanoparticles to the CNT and then to the ZnIn₂S₄ nanosheets, indicating the formation of a photogenerated electron transfer pathway of ZnIn₂S₄ → CNT → Ni. Furthermore, Gibbs free energy of H* adsorption (ΔG_H*) and crystal orbital Hamilton population (COHP) analysis indicate that Ni nanoparticles can serve as active sites, promoting H₂ evolution. Thus, the present study formulates a new strategy for developing low-cost, high-efficiency, non-noble-metal co-catalysts for photocatalytic hydrogen production.

Developing novel nanostructures to enhance the efficiency of solar-to-chemical conversion through integrated photocatalytic hydrogen (H₂) evolution and organic transformation holds great promise in addressing pressing energy and environmental crises. Ternary metal sulfides have garnered considerable attention in photocatalytic H₂ production due to their tunable bandgap and excellent visible light response. Among them, Zn_0.5Cd_0.5S stands out as a reduction photocatalyst with a narrow bandgap, a high conduction band level, and excellent resistance to photocorrosion. However, unitary Zn_0.5Cd_0.5S suffers from a high recombination rate of photogenerated electron/hole pairs, resulting in only a small fraction of charge carriers being involved in the photoreactions, leading to a low quantum efficiency that falls short of practical demand. WO₃, a typical oxidation photocatalyst with a lower valence band position and strong oxidization ability, is an ideal candidate for constructing an S-scheme heterojunction with Zn_0.5Cd_0.5S. Herein, a core-shell structured WO₃/Zn_0.5Cd_0.5S heterojunction with Zn_0.5Cd_0.5S nanosheets vertically growing out of WO₃ nanofibers is fabricated through electrospinning and hydrothermal methods. The distinct disparity in work functions leads to the transfer of electrons from Zn_0.5Cd_0.5S to WO₃ upon contact, creating an interfacial electric field (IEF) and simultaneously bending the energy bands at the interface. As a consequence of IEF, bent energy bands, and coulomb attraction, the photogenerated electrons in the conduction band of WO₃ migrate to the valence band of Zn_0.5Cd_0.5S and recombine with its photoinduced holes, signifying the formation of an S-scheme heterojunction between WO₃ and Zn_0.5Cd_0.5S and enabling efficient separation of powerful charge carriers, as evidenced by in situ irradiated X-ray photoelectron spectroscopy, electron paramagnetic resonance, and time-resolved fluorescence spectroscopy analyses. Benefiting from the unique S-scheme photocatalytic mechanism, along with the effective chemisorption and activation of reactants on the catalyst, the optimized WO₃/Zn_0.5Cd_0.5S heterostructures exhibit exceptional photocatalytic performance in H₂ production (715 μmol·g^-1·h^-1) and the transformation from lactic acid to pyruvic acid without the need for any noble metal cocatalyst, achieving the full utilization of photoinduced electrons and holes. In situ diffuse reflectance infrared Fourier transform spectroscopy, as well as density functional theory simulations, reveal the photoreaction mechanism of H₂ production and organic transformation. This work offers valuable insights into the design and investigation of the mechanism behind novel S-scheme heterojunction photocatalysts, enabling high-performance H₂ production and simultaneous organic transformation.

CO₂ molecules can be converted into various fuels and industrial chemicals through electrochemical reduction, effectively addressing the problems of global warming, desertification, ocean acidification, and other adverse environmental changes and energy supply issues such as excessive utilization of nonrenewable fossil fuels. Generally, the pathway of the CO₂ reduction reaction (CO₂RR) involves multiple proton–electron pairs transferred to the reactants, resulting in the production of multiple reduction products. Here, protons are derived from water molecules under aqueous solvent conditions. Therefore, exploring the effect of water molecules on the proton–electron pair transfer process in CO₂RRs is essential. In this study, we developed a water-mediated hydrogen shuttle model (H-shuttling) as a hydrogenation model to investigate the effect of water molecules on the proton–electron pair transfer process in CO₂RRs and compared it with the widely used water-free direct hydrogenation model (H-transfer), wherein the hydrogen atom is used as a proton. Because copper is a metal electrode material capable of producing hydrocarbons from CO₂ electroreduction with a high faraday efficiency, and nitrogen-doped graphene (C₂N) exhibits excellent catalytic CO₂ activation, we selected a single copper atom-embedded C₂N (Cu@C₂N) as the catalyst. Furthermore, to study the effect of graphene on the CO₂RR activity of Cu@C₂N/G, we selected a graphene-loaded Cu@C₂N composite (Cu@C₂N/G) as the catalyst because graphene was utilized as a substrate to boost the conductivity of the catalyst. In the two hydrogenation models, we investigated the mechanisms of CO₂RRs on Cu@C₂N and Cu@C₂N/G catalysts through density functional theory calculations. Notably, in the H-shuttling model, the H atom combines with the water molecule to form H₃O, which transfers one of its own H atoms to a reactant on the catalyst surface, yielding a reaction intermediate. The H-shuttling model enhances the interaction between the catalyst and intermediate. Graphene, as a substrate, transfers electrons to the Cu@C₂N surface of the Cu@C₂N/G catalyst, which is demonstrated by calculations of the Bader charge transferred between the reaction intermediate and catalyst, as well as the Gibbs free energy of the CO₂ reduction elementary reaction. This effectively lowers the Gibbs free energy of the potential-determining step and enhances the CO₂RR catalytic activity of Cu@C₂N/G. Moreover the limiting potentials of the CO₂RR and hydrogen evolution reaction are determined to obtain the activity and selectivity of the Cu@C₂N and Cu@C₂N/G catalysts. The results indicate that CO₂ molecules on the Cu@C₂N and Cu@C₂N/G catalysts generate HCOOH at low applied potentials, and are able to produce CO, CH₃OH, CH₄, and H₂ as the applied potentials increases.

Converting CO₂ into valuable carbon products can effectively address the current energy crisis and environmental issues. Electrocatalytic CO₂ reduction (ECR), powered by sustainable electricity, is an ideal approach to reduce carbon emissions and promote the carbon cycle. Electrocatalytic CO₂ reduction, powered by sustainable electricity, is an ideal approach to reduce carbon emissions and promote the carbon cycle. However, CO₂ is a thermodynamically inert molecule, making it challenging to obtain the desired products through ECR. Additionally, ECR involves a complex process of multi-electron and proton transfer, requiring different amounts of electrons and protons to gradually form various reduction products. This complexity highlights the urgent need to develop advanced catalysts to overcome the slow reaction kinetics and intricate coupling pathways associated with ECR. Single-atom catalysts (SACs) have emerged as a cutting-edge frontier in heterogeneous catalysis and find extensive application in ECR due to their high atom utilization, excellent activity, and selectivity. SACs defy the traditional design concept of nanoparticle catalysts and exhibit catalytic activity at the atomic level, maximizing their efficiency. Another advantage of SACs lies in their ability to tune the electronic structure of the active central atom through ligand atoms. However, while SACs provide separate metal active sites with no crosstalk between adjacent metal atoms, they do form strong chemical bonding interactions with the support. Currently, SACs for ECR still face challenges such as low selectivity and the goal of achieving high-value product generation. Therefore, optimizing the performance of SACs is of paramount importance. Considering the extensive exploration and application of SACs in the field of ECR, this review aims to summarize the research progress in SAC applications for ECR. It also addresses the challenges and prospects associated with SACs in ECR applications. Specifically, the review covers: (1) the introduction of the ECR reaction mechanism, (2) common preparation strategies for SACs, and (3) the application of SACs in novel devices based on Zn-CO₂ batteries. Finally, the review discusses the challenges and opportunities that SACs present in the context of ECR.

Designing efficient single-atom catalysts (SACs) with high selectivity for the electrocatalytic reduction of nitrate to ammonia formation is both crucial and challenging. This challenge arises due to the intricate and competitive electronic interactions among intermediates, metal active centers, and coordination environments. In this work, we present a comprehensive investigation detailing how to enhance the activity and selectivity of the electrocatalytic nitrate reduction reaction (NO₃RR) by transitioning from single-layer SACs to bilayer SACs (BSACs). This enhancement is achieved through axial d-d orbital hybridization, as elucidated by a systematic study of 27 SACs and BSACs utilizing density functional theory (DFT) calculations. Considering potential pathways involving O-terminal, N-terminal, NO-terminal, and NO-dimer configurations, our calculations reveal that among monolayer SAC candidates, Ti-Pc and V-Pc exhibit low limiting potentials (U_L) of -0.24 and -0.48 V, respectively. Furthermore, analyses of formation energy, dissolution potential, and ab initio molecular dynamics results demonstrate the robust stability of these catalysts under reaction conditions. In these single-layer transition metal (TM)-Pc complexes, the d-band energy levels and occupation numbers are influenced by d_xz/d_yz and p_z orbital hybridizations. Notably, the presence of axial d_z² orbitals introduces a novel avenue for fine-tuning d-band characteristics and reactivity through d_z²-d_z² interactions. Building on these insights, the formation of BSACs using Ti-Pc and V-Pc as substrates, facilitated by axial d-d orbital hybridization, offers a distinctive approach to modulating the catalytic performance of NO₃RR. Significantly, we establish a two-dimensional volcano correlation encompassing the d-band center (ε_d), d_xz + d_yz orbital occupation numbers, and U_L to describe NO₃RR catalytic efficacy. Optimal BSACs should possess concurrent appropriate ε_d and d_xz + d_yz occupation numbers. Remarkably, Ti-Mo and Ti-Ta BSACs emerge as exceptional NO₃RR catalyst candidates, both displaying a remarkably low U_L of -0.13 V. The hybridization between d_z²-d_z² orbitals heightens charge transfer and structural stability within double-layer metals. The scarcity of contiguous metal sites introduces a substantial energy barrier hindering NO₂, NO, and N₂ formation, effectively suppressing NO₃RR by-products. In summation, this investigation imparts valuable insights into effectively enhancing nitrate reduction on SACs and BSACs, offering valuable guidance for advancing electrocatalyst development.

Solid electrolyte interphase (SEI) layers derived from the side reactions between Li metal anode and electrolyte, have great impacts on the electrochemical performance of lithium batteries. In solid-state batteries, SEI layers are also required as the electrical insulators but an ionic conductors, and the mechanical reinforcements for withstanding volume change and suppressing dendritic growth in Li metal anode. Introducing LiF substrates into SEI layers can significantly reduce the electron tunneling ability from Li anode to SEI layer, meanwhile providing the excellent interfacial mechanical strength. However, LiF has a very high energy barrier for ion diffusion, hindering the rapid lithium ion diffusion from SEI layer to lithium anode. Therefore, it is necessary to introduce lithium alloy phases with higher ionic conductivity into the LiF matrix to provide sufficient ion diffusion channels. By the data mining technology, high-throughput first-principle calculation and ab-initio molecular dynamics simulations, this work performed phase diagram and ion diffusion energy barrier calculations to evaluate the thermodynamic stabilities and lithium diffusion abilities of several lithium alloys. 27 lithium alloys that can be used as Li-ion conducting phases in the LiF-based artificial SEI layers are screened. Meanwhile, the structure-function relationship analysis of lithium alloys uncovers that the crystal structure type of lithium alloys has more significant impacts on lithium ion diffusion than alloy elements, that is, lithium alloy structures with the space group of I43d and Fm3m have very excellent lithium ion transport performance, while the diffusion channels of lithium alloy structures with the space group of Pm3m and F43m are narrow, leading to the poor lithium ion transport performance. In addition, this work uncovers a physical image of lithium ion transport in artificial SEI interface, that is, lithium ion diffusion in LiF crystal bulk is quite difficult, while the diffusion resistance at LiF grain boundaries and LiF/LiM alloy interfaces is small.

Conventional oxidation methods of sterol intermediates using the heavy metal chromium as an oxidant has critical drawbacks, such as high toxicity and environmental pollution. Electrocatalytic oxidation (ECO), on the other hand, is considered a promising alternative to conventional processes owing to its high efficiency, eco-friendliness, and controllability. However, ECO currently faces two major challenges: low current densities and reduced space-time yields. In this study, a single-step solvothermal method was employed to synthesize self-supported nickel-iron metal-organic framework (NiFe-MOF) nanosheet electrocatalysts on graphite felt. Various analytical techniques were employed to comprehensively characterize the synthesized NiFe-MOF, including scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Raman spectroscopy, and Brunauer-Emmett-Teller (BET) analysis Furthermore, we implemented a synergistic electrocatalytic strategy by combining the NiFe-MOF catalyst with aminoxyl radicals, i.e., 4-acetamido-2,2,6,6-tetramethyl-1-piperidine-N-oxyl (ACT), to enhance the performance of the ECO reaction. According to the results of structural characterization, the synthesized NiFe-MOF exhibited an amorphous nanosheet structure with a high specific surface area and microporosity. Moreover, we successfully achieved continuous flow with enhanced mass transfer during the electrocatalytic oxidation of 19-hydroxy-4-androstene-3,17-dione (1a) at a current density of 100 mA·cm^-2. The optimal reaction conditions for the ECO reaction were as follows: 100 mmol·L^-1 concentration of 1a, 10% (molar fraction) of ACT, a 1 mol·L^-1 Na₂CO₃/acetonitrile electrolyte (6: 4), room temperature, pH 12.5, and a flow rate of 225 mL·min^-1. Under these conditions, the conversion and selectivity of the reaction reached outstanding levels of 99 and 98%, respectively. Moreover, the space-time yield was calculated to be as high as 15.88 kg·m^-3·h^-1, with a remarkable 35-fold increase compared to that achieved in a batch reactor. The NiFe-MOF/ACT synergistic system demonstrated a high conversion rate for ECO even after 10 reaction cycles. To assess the system’s efficacy in converting other sterols, we conducted an analysis of substrate expansion, which yielded conversion rates exceeding 95%. The SEM, TEM, and XPS results of the catalyst obtained before and after the reaction indicated that the alkaline electrolyte could effectively reconstitute the NiFe-MOF structure, leading to a significant improvement in its performance. By leveraging a ten-fold increased surface area of the NiFe-MOF and constructing a continuous flow electroreactor for ECO with a constant current, we achieved a remarkable space-time yield of 12.99 kg·m^-3·h^-1. Thus, we developed a synergistic electrocatalytic oxidation strategy based on NiFe-MOF/ACT, and this study not only provides valuable insights for realizing the selective oxidation of sterols but also contributes to the advancement of sustainable and efficient chemical processes.

Metal halide perovskite (MHP) materials show great prospects in applications such as solar cells, luminescent displays, and biomedicines, owing to their outstanding visible light absorption, photoelectric conversion, adjustable energy level structure, and low energy consumption. Their exceptional properties, such as high visible light absorption, efficient photoelectric conversion, adjustable energy level structure, and low energy consumption, have attracted significant attention. However, the presence of ion migration in MHPs has been identified as a critical challenge, leading to reduced energy conversion efficiency and device instability. Overcoming this obstacle is crucial for the commercialization of perovskite-based technologies. In recent years, extensive research has been conducted to understand the conditions and mechanisms of ion migration in perovskite materials, as well as develop strategies to mitigate its adverse effects. This paper adopts a dialectical perspective on ion migration, with a specific focus on energy barriers. A comprehensive review is provided, covering the fundamental concepts and formation mechanisms of both irreversible unidirectional and reversible bidirectional ion migrations. This paper begins by presenting a detailed summary of the degradation processes caused by irreversible unidirectional ion migrations phenomena induced by external fields, including illumination, stress/strain, thermal and electrical fields. Understanding the underlying mechanisms of such degradation is essential to address the stability concerns associated with perovskite devices. Moreover, the overview of bidirectional reversible ion migration phenomena in perovskite is presented. The cyclic formation and restoration of Schottky barriers at the interface can significantly influence the photoelectrical properties and impact the overall performance of perovskite devices. Various strategies for regulating ion migrations under external fields are discussed, aiming to enhance device stability and performance. By understanding the energy landscape and migration pathways, researchers can develop effective strategies to control and optimize ion migrations, ultimately improving the photoelectric conversion performance of perovskite devices. This paper provides comprehensive analysis of ion migration in perovskite materials, addressing fundamental concepts, ion migration mechanisms, and strategies for regulating ion migrations. By providing a clear understanding of the challenges associated with ion migration, this work contributes to the advancement of perovskite-based technologies and facilitates their commercialization. Ultimately, the optimization of ion migration control will lead to improved performance and stability of perovskite devices, enabling their widespread adoption in various applications.

As technology and society have continued to develop, the demand for energy storage solutions has increased significantly. Indeed, the development of low-cost, low-carbon, environmentally friendly energy conversion and storage systems is required to address the environmental and ecological problems faced by society. Due to their fast charging and discharging speeds, long cycle life and environmentally friendly characteristics, supercapacitors are widely used in many fields, especially in wind power generation systems, communication and transportation. Among all kinds of electrode materials, silicon carbide (SiC) nanomaterials and SiC-derived carbon (SiC-CDC) materials present long life, high power density, and uncomplicated working mechanisms, which hold significant promise as electrode materials for supercapacitors. So far, various strategies and approaches for controlling the microstructure of SiC nanomaterials and SiC-CDC materials have been developed to achieve further improvement from preparation methods to electrochemical properties. As such, this review systematically introduces the common preparation methods of SiC nanomaterials and SiC-CDC, including the template method, chemical vapor deposition (CVD) method, high temperature halogen etching method and high temperature thermal decomposition process for preparing SiC-CDC. Furthermore, the advantages and disadvantages of different preparation methods are discussed. Additionally, the review covers the progress in employing SiC nanomaterials and SiC-CDC materials as supercapacitor electrode materials in detail. However, despite this progress, the commercial application of SiC nanomaterials and SiC-CDC materials as supercapacitor electrodes has been restricted by some problems, in particular their limited conductivity and poor wettability. More importantly, the low energy density of supercapacitors is still a major problem. Thus, current methods and developmental trends of the strategies to improve electrochemical performance such as “highly conductive carbon material composite”, “heteroatomic doping”, “pseudocapacitance composites”, “multi-stage pore structure design”, “chemical activation” are further analyzed with regards to the current challenges. For example, the introduction of heteroatoms and functional group molecules for reactions into SiC and SiC-CDC materials can inhibit the agglomeration of materials (such as particles and nanosheets), improve their conductivity and wettability, and enhance their specific capacitance. Finally, the challenges and opportunities in the application of SiC nanomaterials and their derived carbons in the field of energy storage for supercapacitors are summarized and prospected. As current preparation methods are limited to the laboratory scale, the combination and improvement of different preparation methods and the development of large-scale and low-cost preparation technology are still the directions of the next efforts. This comprehensive review is expected to further advance the research of SiC nanomaterials and SiC-CDC materials.

Handling hydrazine/urea wastewater through electrochemical oxidation technology (HzOR/UOR) holds significant importance for sewage disposal and nitrogen recycling, as the presence of hydrazine/urea leads to severe environmental issues. On the other hand, hydrazine/urea could potentially serve as a new type of fuel. However, at present, this remains a considerable challenge. The development of a low-cost, highly efficient, and stable electrocatalyst stands as a prerequisite for achieving this goal. In this study, a novel Ni₂P/CoP₃-Zn^vac bimetallic phosphide catalyst is designed and constructed using a hydrothermal-alkali etching-phosphating three-step method. This catalyst integrates P-rich CoP₃, P-poor metallic Ni₂P, and abundant Zn²⁺ cation vacancies into a single structure for HzOR/UOR. Copious P in CoP₃ provides a wealth of negative electrons, which aids in the adsorption of positive reactive intermediates. Meanwhile, P-poor metallic Ni₂P exhibits excellent electrical conductivity, ensuring rapid reaction dynamics. Both physical and electrochemical experiments confirm the successful creation of the Ni₂P/CoP₃-Zn^vac heterojunction, along with the distinctive electron structure of Ni₂P and CoP₃. Electron paramagnetic resonance (EPR) results validate the presence of cation vacancies, which significantly enhance the density of active sites. Consequently, this innovative Ni₂P/CoP₃-Zn^vac heterojunction catalyst displays remarkable electrocatalytic activity, achieving a potential of -47 mV/1.311 V to attain 10 mA·cm^-2 for HzOR and UOR, respectively. The Tafel slopes of 54.3 and 37.24 mV·dec^-1 for HzOR and UOR are significantly smaller than those of single-phased Ni₂P and CoP₃, as well as the two-phased phosphide without alkali etching. Building upon the excellent HzOR/UOR performance of the Ni₂P/CoP₃-Zn^vac heterojunction, a two-electrode cell for direct hydrazine fuel cells (DHzFC) and direct urea-hydrogen peroxide fuel cells (DUHPFC) is assembled with a Ni₂P/CoP₃-Zn^vac anode. This configuration demonstrates a maximum power density of 229.01 mW·cm^-2 for DHzFC and 16.22 mW·cm^-2 for DUHPFC. Moreover, both DHzFC and DUHPFC exhibit exceptional stability for up to 24 h. A homemade aqueous Zn-Hz battery, equipped with a Ni₂P/CoP₃-Zn^vac cathode, further demonstrates its practicality for energy conversion. This work underscores a promising avenue for developing cost-effective and highly stable solutions for UOR and HzOR.

Metallic lithium (Li) offers Li metal batteries (LMBs) with an opportunity to meet the high-energy demand in many fields. At present, the main cathode materials used for high-energy-density batteries are nickel-rich layered oxides, including nickel cobalt lithium manganese oxides (NCM) with intercalation chemistry. According to this plan, NMC811 demonstrates great merits in this aspect. However, there are still many problems with Li metal anode. The failure of Li anode is mainly caused by the high reactivity of Li metal, which can cause irreversible continuous reactions between Li and electrolyte to shorten cycling life. Due to multiple electroplating and stripping processes, Li anode undergoes significant volume and morphology change, increasing side reactions and the growth of Li dendrites caused by the first two factors. Electrolyte engineering, as a simple and effective modification method, can effectively solve the above problems. Among them, using electrolyte additives is a simple, efficient, and economical electrolyte engineering strategy. Herein, we proposed an anion acceptor electrolyte additive strategy for optimizing the component/structural characteristics of solid/cathode electrolyte interphases to inhibit the growth of Li dendrites and Li⁺ transition on cathode surface for enhancing cycling and rate performance of Li||NCM811 battery, which is also ascribed to the regulation of Li⁺ solvation structure by hexafluorobenzene (HFBen) to realizing the stability of PF₆^- and the conductivity enhancement of electrolyte. As expected, Li||Li cells with 1% (wt) HFBen-contained electrolyte could achieve a stable cycling above 400 h at 1 mA·cm^-2, and the capacity retention rate of Li||NCM811 battery could reach 75% after 100 cycles at 200 mA·g^-1. Finally, the cycling and rate performance of Li||NMC811 batteries were significantly enhanced at 4.5 V with the help of HFBen. This work demonstrates that HFBen as an additive can effectively improve the electrochemical performance of LMBs. Moreover, the interfacial reaction mechanism across the batterywas analyzed and studied. This study provides new insights for the interface reaction between electrolyte and Li anode.

Rechargeable zinc-air batteries (ZABs) have been extensively investigated owing to their high power density and environmental friendliness. However, the slow kinetics of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) processes limit their practical application. Currently, IrO₂ and RuO₂ are considered the optimal OER electrocatalysts, and Pt/C is the most effective ORR electrocatalyst. However, the practical application of Pt, Ir, and Ru in ZABs is severely limited owing to their low natural abundance and high cost. Therefore, the fabrication of inexpensive and high-performance bifunctional catalysts is essential for the development of rechargeable ZABs. Transition-metal alloys have a high electrical conductivity and low energy barrier for the reaction of oxygen, and thus they are considered promising ORR electrocatalysts. Transition-metal nitride-transition-metal alloy core-shell nanostructures can be fabricated to improve the bifunctional electrocatalytic activity. In this study, a bifunctional electrocatalyst with Fe_0.64Ni_0.36@Fe₃NiN core-shell structures encapsulated in N-doped carbon nanotubes (Fe_0.64Ni_0.36@Fe₃NiN/NCNT) was designed for highly efficient rechargeable ZABs. Fe_0.64Ni_0.36@Fe₃NiN/NCNT was synthesized by pyrolyzing the nickel-iron-layered double hydroxide (NiFe-LDH) precursor, followed by ammonia etching of the Fe_0.64Ni_0.36 alloy. The core-shell structure produced more ORR/OER active sites. The Fe_0.64Ni_0.36 core exhibited high electrical conductivity, which facilitates charge transfer. The Fe₃NiN shell enhanced the OER performance and improved the bifunctional performance. Moreover, the NCNT structures not only efficiently enhanced the mass transfer efficiency and intrinsic electrical conductivity, but also provided a large electrochemical active surface area. The high anticorrosion property of the Fe₃NiN shell effectively protected the Fe_0.64Ni_0.36 core, which consequently enhanced electrocatalyst stability during the electrochemical processes. The protective carbon layer and the superior chemical stability of the Fe₃NiN shell resulted in the ultrahigh stability of Fe_0.64Ni_0.36@Fe₃NiN/NCNT. The catalyst exhibited an excellent bifunctional oxygen electrocatalytic performance, with a half-wave potential of 0.88 V for the ORR and low OER overpotential of 380 mV at 10 mA∙cm^-2. Moreover, the catalyst exhibited electrochemical stability (92.8% current retention after 8 h). In addition, the Fe_0.64Ni_0.36@Fe₃NiN/NCNT-based ZAB exhibited a higher peak power density (214 mW·cm^-2) than the ZABs based on Pt/C+IrO₂ (155 mW·cm^-2) and Fe_0.64Ni_0.36/NCNT (89 mW·cm^-2). Moreover, the Fe_0.64Ni_0.36@Fe₃NiN/NCNT-based ZAB delivered a high capacity of 781 mAh·g^-1, while the ZABs based on Fe_0.64Ni_0.36/NCNT and Pt/C+IrO₂ reached capacities of 688 and 739 mAh·g^-1, respectively. Furthermore, the Fe_0.64Ni_0.36@Fe₃NiN/NCNT-based ZAB exhibited ultralong cycling stability (cycle life > 1100 h), which exceeded those of Pt/C (50 h) and Fe_0.64Ni_0.36/NCNT (450 h). We propose that this study will facilitate the design of novel catalysts for highly stable and efficient ZABs.

The GABA_A receptor mainly mediates inhibitory signal transmission in mammalian central nervous systems and is the key target of sedative-hypnotics. However, the long-term use of sedative-hypnotics often leads to drug resistance, necessitating the development of novel sedative-hypnotics. This development can be achieved with novel scaffolds designed via the computer-aided drug design methods to obtain significant advantages. In this study, robust virtual screening models were established by identifying effective positive allosteric modulators of the GABA_A receptor from ChEMBL and BindingDB databases. These compounds combined with randomly extracted negative compounds were firstly applied for a 10-fold cross validation and grid search to establish machine learning models which were subsequently evaluated in an independent test set. In this step, 4 machine learning methods and 6 fingerprints were used to establish 24 models. In the test set, the CDK_LR model performed the best (MCC = 0.751) and was used for subsequent virtual screening. Two effective molecular docking models were also established based on conformation 6D6T and 6D6U, wherein the root mean square deviation (RMSD) values of redocking experiments were 1.141 and 1.505 Å (1 Å = 0.1 nm), respectively. During the virtual screening, 41112 compounds from a commercial database were scanned by machine learning, molecular docking, and molecular mechanics-generalized Born surface area models. After the screening, 16 hits were obtained, 4 of which were structurally novel positive hits verified by whole-cell patch-clamp electrophysiology experiments. The compound GPR120 was verified experimentally at both the cell and animal levels. In cortical neurons recombinantly expressing α1β2γ2-type receptors, at 10 and 50 µmol∙L⁻¹, GPR120 could potentiate GABA EC_3-10 current by 71.5% and 163.8%, respectively. Total decomposition contribution analysis and point mutation experiment showed that the key binding site between GPR120 and the GABA_A receptor is H102, similar to that of the positive drug Diazepam. To further verify GPR120 function at the animal level, locomotor activity and loss of righting reflex (LORR) tests were performed. GPR120 inhibited the locomotor activity of mice, which recovered after 6 h, indicating that GPR120 is a moderate sedative. In the pentobarbital sodium-induced righting reflex hour test, GPR120 (20 mg∙kg⁻¹) significantly shortened the time to start LORR and prolonged its duration compared with the saline control group. In summary, using integrated virtual screening methods, GPR120 was identified as a moderate sedative with a novel scaffold.

Surface reconstruction inevitably occurs during pre-catalysis for the oxygen evolution reaction (OER); however, obtaining OER electrocatalysts with high performance and stability remains a challenge. In this study, we have developed a bimetallic leaching-induced surface reconstruction strategy to fabricate efficient electrocatalysts for water oxidation. Microcolumn arrays consisting of α-CoMoO₄, K₂Co₂(MoO₄)₃, Co₃O₄, and CoFe₂O₄ four-phase oxides were integrated as pre-catalyst by a hydrothermal, ion-exchange, and subsequent annealing process. In situ Raman spectroelectrochemical and ex situ X-ray diffraction (XRD) studies revealed that the rapid dissolution of the unstable component K₂Co₂(MoO₄)₃ triggered the adaptive leaching of Mo and K, which accelerated the transformation of the surface-enriched α-Co(OH)₂ to the active phase of CoOOH at low voltage. Furthermore, the stable CoFe₂O₄ component couples the reconfigured new phase CoO with the amorphous layer CoOOH to form a compact hierarchical structure of CoFe₂O₄@CoO@CoOOH, which plays the role of a nanofence and effectively prevents the catalyst from over-reconstruction, thus achieving excellent catalytic stability. This work provides a novel idea for designing OER catalysts with excellent activity and stability at high current densities.

Phenothiazines (PTZs), have received a lot of attention for many optoelectronic applications, such as hole-transporting layers, functioning as host materials for organic light-emitting diodes; dye sensitizers in dye-sensitized solar cells; and hole-transporting materials for perovskite solar cells. However, studies on benzophenothiazine materials are limited. In this study, we synthesize three isomeric bis-benzophenothiazine compounds (D-PTZa, D-PTZb, and D-PTZc), all bearing an aromatic ring at the 1, 2-, 2, 3-, and 3, 4-positions, respectively. Next, we systematically investigate the relationship between their structures and properties and compare them with bis-phenothiazine compounds (D-PTZ). The highest occupied molecular orbital (HOMO) distributions for D-PTZb and D-PTZc are dispersed over benzophenothiazine moities, whereas the lowest unoccupied molecular orbitals (LUMOs) are localized at the middle phenyl- and naphthyl-groups, which are similar frontier orbital distribuitions to the D-PTZ case. For D-PTZa, the steric hindrance between the phenyl groups at the 1, 2- and middle positions increases, significantly distorting its spatial structure. Therefore, its HOMO and LUMO distributions differ from those of D-PTZb and D-PTZc. Notably, the HOMOs in D-PTZa are dispersed over the middle phenyl group and nitrogen atom, whereas the LUMOs are localized at the naphthyl group. The hole/electron excitation and frontier orbital analyses demonstrate that strong local π → π* transition mixing with weak charge transfer transition is responsible for the luminescence of D-PTZb and D-PTZc. Interestingly, the ultraviolet–visible absorption spectra of all samples exhibit strong π → π* transition absorption and weak n → π* transition absorption. Furthermore, the conjugated length of the molecule can be effectively increased with the introduction of an aromatic ring, resulting in a red-shift in the maximum absorption wavelength. Compared to D-PTZ, D-PTZa emits yellow-green light with a photoluminescence quantum efficiency (PLQE) of 14%. In addition, the introduction of a phenyl group at the 2, 3-position effectively stabilizes the HOMO energy level, slightly increasing its π → π* transition gap, while also emitting blue light with a PLQE of 1.7%. For D-PTZc, the introduction of a phenyl group at the 3, 4-position better linearizes the LUMO distribution, thereby stabilizing the LUMO energy level and reducing its π → π* transition gap. The maximum emission peak is observed at 520 nm, emitting yellow-green light with a PLQE of 13%. Overall, our molecular design and results on structure–property relationships can provide fundamental guidance for the design of phenothiazine derivatives with specific photoelectric performance.

Carbon dioxide (CO₂) serves as a non-toxic, abundant, cheap, and renewable C1 feedstock in synthetic chemistry. The synthesis of high value-added fine chemicals, such as organic carboxylic acids, using CO₂, is always a focal point of research. Due to the thermodynamic stability and kinetic inertness of carbon dioxide, traditional carboxylation reactions utilizing CO₂ often require harsh reaction conditions. However, organic electrochemical synthesis, which employs electrons as clean reagents to drive the reaction and avoids additional chemical oxidants or reductants, has emerged as a safer, more economical, highly selective, sustainable, and environmentally friendly method for preparing fine chemicals. Electrocarboxylation, which leverages organic electrochemical synthesis to catalytically transform CO₂, provides a milder and more efficient route for CO₂ utilization. Among these approaches, electrocarboxylation of organic halides or pseudohalides containing C―X bonds with CO₂ has been extensively investigated as a means to access value-added carboxylic acids. Phosphates, known for their good leaving group properties, find extensive applications in organic synthesis. Under reductive conditions, the radical anion generated by benzyl phosphate easily dissociates into a benzyl radical and a phosphate anion. Hence, it can serve as an attractive substrate for participating in electrocarboxylation reactions. In this study, we report the highly efficient electrocarboxylation of benzylic phosphate and phosphinate derivatives using CO₂ as the carboxyl source. The constant current reaction took place in an undivided cell, employing glassy carbon as the cathode, and magnesium as the sacrificial anode, in a mixed solvent of DMF and THF. Additionally, this mild electrolysis can be carried out under nonsacrificial anode conditions, using cheap carbon felt electrode as both the nonsacrificial anode and cathode and N,N-diisopropylethylamine as an external reductant, therefore provided operationally simple and highly efficient synthetic method toward aryl acetic acids in moderate to good yield. The broad substrate scope, simple operation, facile scalability, and highly efficient transformation of phosphates into high value-added aryl acetic acids under mild conditions demonstrate the potential applicability of this reaction. To gain insight into the possible reaction mechanism, several control experiments were conducted. Isotope-labeling ¹³CO₂ experiment, cyclic voltammetry experiments, radical trapping reactions, and deuterium-labeling experiment indicated that cathodically generated benzylic radical and benzylic anion were key intermediates. Moreover, the single electron reduction of CO₂ to CO₂^•− might also occur during the reaction.

Electrocatalysts play a pivotal role in the electrochemical water splitting process to produce hydrogen fuel. The advancement of this technology relies on the development of efficient, cost-effective, and readily available electrocatalysts. Two-dimensional (2D) MXene materials have garnered significant attention due to their unique physicochemical properties, rendering them promising candidates for electrocatalytic applications. While there are numerous types of MXene materials available, only a few possess intrinsic hydrogen evolution reaction (HER) catalytic activity. However, MXene materials can serve as excellent platforms for enhancing catalytic HER activity by combining them with other substances, owing to their large specific surface area, high conductivity, and abundant surface functional groups. In this study, we initially conducted a predictive analysis using density functional theory (DFT) to assess the potential of combining CoP with Ti₃C₂T_x MXene materials (where T_x represents ―F and ―OH functional groups) in reducing the adsorption free energy of hydrogen (ΔG_H*). The results indicated that the CoP-Ti₃C₂T_x nanocomposites exhibited a ΔG_H* value approaching 0, suggesting promising HER performance. Following this theoretical prediction, we synthesized the CoP-Ti₃C₂T_x MXene nanocomposites. Comprehensive characterization of the synthesized nanocomposites was performed using various techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). These analyses confirmed the successful decoration of CoP on the MXene nanosheets and provided insights into the structural and compositional properties of the nanocomposites. Furthermore, we evaluated the electrochemical performance of the CoP-Ti₃C₂T_x nanocomposites through linear sweep voltammetry and chronoamperometry measurements. The results demonstrated superior catalytic activity and stability for the HER compared to pure Ti₃C₂T_x and CoP catalysts. Specifically, the as-synthesized CoP-Ti₃C₂T_x MXene nanocomposites exhibited remarkable electrocatalytic HER kinetics, featuring a low overpotential of 135 mV at a current density of 10 mA∙cm⁻² and a small Tafel slope of 48 mV∙dec⁻¹ in a 0.5 mol∙L⁻¹ H₂SO₄ solution, with the electrocatalyst maintaining stability for up to 50 h. Subsequent theoretical calculations were conducted to elucidate the factors contributing to the exceptional electrocatalytic performance of the CoP-Ti₃C₂T_x MXene nanocomposites. It was determined that the metallic conductivity of Ti₃C₂T_x MXene materials, well-structured interface charge transfer, and optimized electronic structure of CoP played significant roles in enhancing catalytic activity. In conclusion, this study underscores the potential of CoP-decorated Ti₃C₂T_x MXene nanocomposites as promising electrocatalysts for efficient HER in various energy conversion and storage devices. These findings represent a significant contribution to the development of robust and efficient catalysts for hydrogen generation, a critical component of renewable energy applications and sustainable development.

Semiconductor photocatalysis makes full use of solar energy, serving as a potent tactic to solve the worldwide energy deficit and safeguard the environment. Bismuth-based photocatalysts stand out among various photocatalysts as a significant area, due to their unique crystal structure, favorable mixed electron band structure, diverse composition, and huge potential for solar catalytic conversion. This document reviews the rational design of Bi-based photocatalysts for solar energy. Recent advancements in diverse Bi-based photocatalysts such as Layered Bi, Bismuth element, BiVO₄, Bi₂S₂, and Bi₂O₃ are highlighted. Secondly, the synthesis strategies of Bi-based catalysts, including hydrothermal/solvothermal, chemical precipitation, and solid-state reaction, are summarized. Third, various structural regulation methods to improve the photocatalytic performance, including defect regulation, heteroatom doping, morphology, SPR effect utilization, and heterojunction construction, are systematically introduced. Additionally, a focus is given to the exclusive applications of Bi-based photocatalysts, including CO₂ reduction, water decomposition, N₂ fixation, NO_x removal, H₂O₂ production, and selective organic synthesis, followed by an introduction of advanced in situ characterization techniques of the Bi-based photocatalysts. Ultimately, the forthcoming obstacles are underscored, and a future outlook for Bi-based photocatalysts is anticipated. This review aims to offer detailed instructions for comprehensively understanding and logically crafting effective bismuth-based photocatalysts, while also encouraging novel ideas and advances in energy and environmental fields, contributing to the goals of green chemistry and sustainable development.

With increasing global energy demand and stricter environmental protection requirements, energy storage technology has become a research hotspot in the global energy field. New types of energy storage devices continue to emerge owing to the continuous development of cost-effective energy storage technology. Among them, potassium-ion batteries have received widespread attention as a new type of alkali metal ion battery because of their high capacity and low cost and are considered one of the future development directions. However, the research on potassium-ion batteries is still in its infancy, with many challenges to overcome regarding practical applications. A key factor affecting the performance of potassium-ion batteries is the anode material, as it not only affects the manufacturing costs but also directly affects the power density and energy density of the battery. Traditional anode materials for lithium-ion batteries cannot meet the requirements of potassium-ion batteries. Therefore, developing high-performance anode materials suitable for potassium-ion batteries is an important research direction at present. The charge and discharge rate and cycling life of potassium-ion batteries also need further improvements. Currently, the low-rate performance, short cycle life, and unsatisfactory practical capacities limit their practical application and commercialization. However, the future of potassium-ion batteries remains promising. Upon resolving the aforementioned issues, potassium-ion batteries will have diverse application prospects, such as electric vehicles, energy storage stations, and smart grids, providing important support for solving energy problems. Therefore, the research and development of potassium-ion batteries are an important direction in the global energy field. Current research efforts are primarily focused on exploring novel anode materials with exceptional ratability and cyclability. In this regard, we synthesized a new type of anode material based on bismuth telluride (Bi₂Te₃) and experimentally studied its applicability in potassium-ion batteries. The performance of Bi₂Te₃ anode for potassium-ion batteries has been limited by its structural instability and slow electrochemical reaction kinetics. In this study, rod-like Bi₂Te₃ was grown on accordion-like MXene, followed by P-doping to obtain a high-performance P-Bi₂Te₃/MXene superstructure. This novel anode had abundant Te vacancies and good self-auto adjustable function, providing excellent cycling stability (323.1 mAh·g^-1 after 200 cycles at 0.2 A·g^-1) and outstanding rate capability (67.1 mAh·g^-1 at 20 A·g^-1). Kinetic analysis and ex situ characterization indicate that the superstructure exhibits superior pseudocapacitive properties, high electrical conductivity, favorable diffusion capability, and reversible insertion and conversion reaction mechanism.

Selective hydrogenation of CO₂ to methanol with renewable H₂ is a promising approach to effectively utilize the anthropogenic greenhouse gas CO₂ in response to the growing environmental and energy challenges. Recently, MoS₂ has gained attention as an attractive catalyst for CO₂ hydrogenation due to its tunable S vacancy sites. However, its catalytic reactivity towards methanol production is still unsatisfactory because the general edge S vacancy site tends to favor CH₄ formation. Herein, we report that the alkali K decorated MoS₂ catalyst enables a dramatically enhancement in selective hydrogenation of CO₂ to methanol, in contrast to the pristine MoS₂ nanosheets that produce mainly CH₄. We incorporated the K promoter into MoS₂ using a simple physical mixture method, and we found that the loading of K has a crucial impact on the catalytic performance. The K-MoS₂ catalyst with an appropriate K loading of 0.5 wt.% (mass fraction) delivers an optimized methanol selectivity of 81% and a methanol space time yield of 3.6 mmol·g^-1·h^-1 at mild reaction conditions of 220 °C and 5 MPa, which greatly outperforms the bare MoS₂. Higher K loading would lead CO as the dominating product, while lower K loading is insufficient to tune the selectivity. Detailed characterization techniques, including X-ray diffraction (XRD), Raman, H₂-temperature programmed reduction (TPR), electron paramagnetic resonance (EPR), X-ray photoelectron spectroscopy (XPS), CO-diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and H₂-D₂-temperature programmed surface reaction (TPSR), reveal that K atoms tend to occupy the edge sites on MoS₂ and serve as electron donators, which enhance the density of states at the Fermi surface and the basicity of the edge active sites, while preventing H₂ dissociation on the edge S vacancy. The reaction mechanism, as studied by CO₂-temperature programmed desorption (TPD) and CO₂ + H₂ DRIFTS, suggests a reverse water-gas shift route for CO₂hydrogenation to methanol. The increased basicity at the edge active site has therefore facilitates CO₂ adsorption and lowers the activation barrier for CO₂ dissociation to CO. It also restrains the methanation activity of intermediate CO and directs the reaction path toward CO hydrogenation to methanol. However, the excessive inhibition of H₂ dissociation at higher K loading levels causes the facile desorption of CO, resulting in high CO selectivity. These results highlight the appearing effect of K promoter on modulating the edge active sites of MoS₂ to favor methanol formation over CH₄, and provide a simple yet effective strategy for tuning the structure and catalytic performance of MoS₂. This extends the application of MoS₂-based catalysts in methanol synthesis via CO₂ hydrogenation.

As the most advanced battery technology to date, lithium-ion battery has occupied the main battery markets for electric vehicles and grid scale energy storage systems. However, the limited lithium reserves as well as the high price raise concerns about the sustainability of lithium-ion battery. Although sodium-ion battery is proposed as a good supplement to lithium-ion battery, expensive and flammable electrolyte components, harsh assembly environments and potential safety hazards have limited the rapid development to a certain extent. The organic electrolyte was replaced with an aqueous solution to construct a new type of aqueous sodium ion battery capacitor (ASIBC). It is of great significance for next-generation energy storage system owing to its low cost, high power, and inherent safety. However, applicable ASIBC system is rarely reported so far. Here, a rechargeable alkaline sodium ion battery capacitors constructed by using Na_0.44MnO₂ cathode, activated carbon (AC) anode, 6 mol∙L^-1 NaOH electrolyte, and cheap stainless-steel current collector. Because of high overcharge tolerance of Na_0.44MnO₂ cathode in alkaline electrolyte, the shortcomings of the half-sodium Na_0.44MnO₂ cathode and low initial Coulombic efficiency of AC anode can be resolved by in situ overcharging pre-activation process during first charging. The available capacity of Na_0.44MnO₂ in half cell largely increased from ~40 mAh∙g^-1 (neutral electrolyte) to 77.3 mAh∙g^-1 (alkaline electrolyte) due to broadened Na⁺ intercalation potential region. Thus, the AC||Na_0.44MnO₂ ASIBC delivers outstanding electrochemical properties with a high energy density of 26.6 Wh∙kg^-1 at a power density of 85 W∙kg^-1 and long cycling stability with a capacity retention of 89% after 10,000 cycles. The advantages of the alkaline electrolyte for the AC||Na_0.44MnO₂ ASIBC can be concluded as follows: (1) through the in situ electrochemical pre-activation process, the overcharging oxygen evolution reaction during first charging process can balance the adverse effects of the half-sodium Na_0.44MnO₂ cathode and low initial Coulombic efficiency of AC anode on the energy density of full cell; (2) the overcharging self-protection function can promote the generated oxygen to be eliminated at anode during overcharging, which improves the system safety; (3) the low-cost materials in alkaline environment can be scaled up to construct AC||Na_0.44MnO₂ ASIBC. In addition, the AC||Na_0.44MnO₂ ASIBC also possesses wide operating temperature range, achieving satisfied electrochemical performance at a high temperature of 50 ℃ and a low temperature of -20 ℃. Considering the merits of low-cost, high safety, no toxicity and environment-friendly, we believe the AC||Na_0.44MnO₂ rechargeable alkaline sodium-ion battery capacitors have the potential to be applied to large-scale energy storage.

Owing to their remarkable miniaturization and integration capabilities, all-solid-state thin-film lithium-ion batteries are quite appropriate as the on-chip power for microsystems, such as implantable medical devices, micro-electro-mechanical systems and integrated circuits. The performance of the all-solid-state thin-film lithium-ion batteries is greatly determined by the anode film. Metal Li is usually adopted as the anode material, however, the issues, including Li dendrite growth and poor thermal stability, hinder its applications in the high-temperature and high-safety fields, such as industrial and military. Therefore, various anode materials have been investigated in recent years. Unfortunately, few anode materials can achieve high specific capacity and good stability simultaneously. Due to its relatively high specific capacity and good electrochemical stability, LiNbO₃ has been widely used as a coating layer in the batteries and has been demonstrated to effectively suppress side reactions at the electrode|electrolyte interface. However, there is still lack of deep understanding of the electrochemical characteristics of LiNbO₃; also, no previous work has been performed to explore the applications of LiNbO₃ in the all-solid-state thin-film lithium-ion batteries. In this work, the electrochemical characteristics of LiNbO₃as a new anode material are carefully investigated. It is found that the LiNbO₃anode has relatively high specific capacity (410.2 mAh∙g^-1), high rate capability (80.9 mAh∙g^-1 at 30C), good cycling stability (100% capacity retention over 2000 cycles at 1C) and high ionic conductivity (4.5×10^-8 S∙cm^–1 at room temperature). Moreover, an all-solid-state thin-film lithium-ion battery with a Pt current collector|NCM523 cathode|LiPON electrolyte|LiNbO₃ anode|Pt current collector configuration is also prepared. This full battery presents good performance in terms of its relatively high area capacity (16.3 μAh∙cm^-2 at a current density of 0.5 μA∙cm^-2), good rate characteristic (1.9 μAh∙cm^-2 even at a high current density of 30 μA∙cm^-2) and good stability (86.4% capacity retention after 300 cycles). Particularly, the retained capacity remains as high as 95.6% even when this full battery operates continuously at 100 ℃ for ~200 h, demonstrating its good thermal stability. As confirmed by both the electrochemical and micro characterization, the LiPON|LiNbO₃interface is quite stable under both the repeated charge/discharge cycling and high temperature operation, which contributes to the good performance of this full battery even under high temperatures. For comparison, the LiPON|Li interface degrades significantly under high temperatures, thus resulting in poor performance of the corresponding full battery. This work is helpful to develop a new anode film and all-solid-state thin-film lithium-ion battery which is suitable for the industrial and military applications.

Highly coveted for their exceptional energy density, extended cycle life, impressive rate capability, and thermal stability, lithium-ion batteries (LIBs) stand out as the optimal power sources for real-world applications, ranging from portable electronics to electric vehicles (EVs). In this context, coaxial electrospinning has emerged as a compelling technique for fabricating nanofiber materials endowed with properties ideally suited for LIBs. These properties include a high specific surface area, exceptional porosity, a substantial aspect ratio, and facile surface modification. This comprehensive review encapsulates the fundamental principles, practical applications, and recent strides in coaxial electrospinning, particularly in the preparation of crucial LIB components such as cathodes, anodes, and separators. The intricate relationships between the micro/nanostructures of coaxially electrospun fiber materials and their resultant battery performances are meticulously examined. Additionally, the review outlines future directions and underscores the challenges inherent in advancing the field of coaxial electrospinning for LIBs.

The use of solar energy as an inexhaustible resource to conduct photocatalytic water splitting in hydrogen (H₂) production can alleviate the worldwide energy crisis and achieve carbon neutrality. However, research in photocatalytic H₂ evolution reaction (HER) is extremely challenging in terms of exploring the current development of an active and durable graphitic carbon nitride (g-C₃N₄)-based photocatalyst. Several parameters of pristine g-C₃N₄ require structural, physical, and chemical improvements, such as optimization of the surface area, electron transfer, and photo-generated carrier recombination, to render the g-C₃N₄ suitable for photocatalysis. In this study, the development of an efficient and robust S-doped g-C₃N₄(S-g-CN) catalyst was pursued that involves doping nitrogen (N) active sites of g-C₃N₄ with sulfur (S) dopants via one-step calcination of the sulphate and melamine precursors. A combination of structural and spectroscopic fingerprints was established to distinctly determine the realization of S-doping onto the g-C₃N₄ structure. We obtained the optimum Gibbs free energy of adsorbed hydrogen (ΔG_H*) for S-g-CN at the S active sites, which is nearly zero (~0.26 eV), suggesting that the filled S dopants play an essential role in optimizing the adsorption and desorption processes of H-active intermediates. The results of atomic force and transmission electron microscopies (AFM and TEM) demonstrated that the produced S-g-CN catalyst has an ultrathin nanosheet structure with a lamellar thickness of approximately 2.5 nm. A subsequent N₂ sorption isotherms test revealed a substantial increase in the specific surface area after the integration of S dopants into the g-C₃N₄ nanoskeleton. Moreover, the incorporation of S atoms into the g-C₃N₄ significantly increased the carrier concentrations, improving the transfer, separation, as well as the oxidation and reduction abilities of the photo-generated electron-hole pairs. Leveraging the favorable material characteristics of the S-doped two-dimensional nanostructures, the resulting S-g-CN achieved a high H₂ evolution rate of 4923 μmol·g^-1·h^-1, which is 28 times higher than that of the pristine g-C₃N₄. Additionally, the developed S-g-CN possessed a high apparent quantum efficiency (3.64%) at visible-light irradiation. When compared to the recently reported S-doped g-C₃N₄-based photocatalysts, our optimal S-g-CN catalyst (S-CN_1.0) showed one of the best HER catalytic activities. Our rational design is based on an effective strategy that not only explored a promising HER photocatalyst but also aimed to pave the way for the development of other high-performance g-C₃N₄ based catalysts.

MXenes are two-dimensional metal carbides, nitrides, and carbonitrides that are typically achieved by selectively etching the A-site elements from their corresponding MAX phase precursors. Thanks to the merits including high mechanical stability, excellent conductivity, and a high specific surface area, MXenes have attracted widespread attention in the field of energy storage and conversion. By far, most studies are focus on the synthesis and applications of Ti- or V-based MXenes. Mo-based MXenes, while less investigated due to the difficulty of synthesis, have shown significant potential in various fields, including electrochemical biomolecular sensing, electrocatalysis, and energy storage. The conventional method of preparing Mo-based MXenes involves etching precursors with hazardous HF-containing solutions, which is not only time-consuming but also poses safety risks. In this study, we present a Lewis molten salt synthesis approach to prepare Mo₂CT_x MXene by etching Mo₂Ga₂C precursor that eliminates the need for hazardous HF and significantly reduces the synthesis time. The impact of etching temperature and time on the phase and microstructure of Mo₂CT_x MXene were carefully investigated, and our findings indicate that the Mo₂Ga₂C precursor can be almost fully etched at 600 °C for just 30 min using the molten salt method, which is a challenging feat to achieve using HF etching. Furthermore, it is found that Mo₂CT_x MXene can be obtained in a wide temperature range from 600 to 800 °C with excellent structural stability. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) confirmed the selective etching of Ga atoms from Mo₂Ga₂C and the successful preparation of Mo₂CT_x MXene, and X-ray photoelectron spectroscopy (XPS) suggests the preservation of Mo-C bonds in the Mo₂CT_x layered structure. The hydrogen evolution reaction (HER) performance of Mo₂CT_x MXene prepared by the molten salt method was investigated in alkaline electrolytes. The molten salt derived Mo₂CT_x MXene displayed exceptional catalytic performance for the HER, maintaining long-term stability in alkaline conditions, and exhibiting a low overpotential of only 114 mV and a Tafel slope of 124 mV∙dec⁻¹ at 10 mA∙cm⁻². The much larger double layer capacitance of molten salt derived Mo₂CT_x MXene as compare to the Mo₂Ga₂C precursor suggests that accordion-like structure can greatly increase the electrochemical active sites and thus plays a key role in boosting the catalytic performance.

Solid oxide electrolysis cells (SOECs) could convert CO₂ to CO powered by clean electricity with low overpotential, high Faradaic efficiency, and high current density. Since the performance of SOEC is affected by sluggish oxygen evolution reaction (OER) kinetics at the anodes, the modification of anode materials is crucial for the further application of SOEC. Perovskites with high configurational entropy exhibit high catalytic activity in many reactions, but are rarely reported in SOECs. Herein, two kinds of high entropy perovskites (HEPs), with formulas of (Pr_0.2La_0.2Sm_0.2Nd_0.2Gd_0.2)BaCo₂O_6-δ (A-HEP)and Pr(Ba_0.2Sr_0.2Ca_0.2Na_0.2K_0.2)Co₂O_6-δ (A'-HEP), are synthesized by doping different rare earth metal, and alkaline metal or alkaline earth metal ions into A-site and A'-site of the double perovskites. Rietveld refinement of X-ray diffraction patterns and elemental maps of scanning electron microscope images confirm the successful synthesis of the two samples. The tetragonal double perovskite structure of A-HEP and the transformation to orthorhombic structure of A'-HEP due to the difference in average atomic radii and oxidation states of the doped ions are also detected. Co 2p X-ray photoelectron spectroscopy (XPS) and O K-edge X-ray absorption spectroscopy reveal that the average oxidation state of Co is lifted from +3.23 in A'-HEP to +3.39 in A-HEP, and the hybridization of Co 2p and O 1s orbitals is also enhanced in A-HEP, which increase the electron transfer pathway and reduce the transfer barrier. Therefore, the electrical conductivity of A-HEP at 800℃ is higher than that of A'-HEP. Moreover, the increased absorption oxygen species concentration of A-HEP in O 1s XPS and O₂-temperature programmed desorption results indicates more surface oxygen vacancies, thus increasing active sites for the anodic OER. Consequently, the anodic polarization resistances related to oxygen transportation, electron transfer and surface reaction processes are decreased remarkably in A-HEP, resulting in a high current density of 1.76 A·cm^-2 at 800℃ and a stability of 200 h. This work presents a new method for designing high-performance HEPs as SOEC anode materials.

With the increasing use of fossil energy sources, the concentration of CO₂ in the atmosphere is rising, leading to environmental challenges. However, the conversion of CO₂ into high value-added chemicals through catalysis presents an opportunity to address these issues and create a new pathway for fuel synthesis, ultimately helping to reduce CO₂ emissions and achieve carbon neutrality. Among various methods, the CO₂ electroreduction reaction (CO₂RR) using renewable clean energy has garnered significant attention due to its mild reaction conditions, controlled reactions progress, environmental friendliness, and numerous value-added products it can yield. In this context, imidazolium-based materials and their derivatives have emerged as promising candidates for CO₂RR. These materials have a strong affinity for CO₂ and find applications as both electrolytes and electrocatalysts in CO₂RR systems. So one of their key advantages, especially Im-ILs, is their ability to enrich CO₂ in catalytic systems, effectively preventing the undesired hydrogen evolution reaction (HER) and enhancing the selectivity towards CO₂RR products. Understanding the interaction mechanism between imidazolium-based ionic liquids (Im-ILs) and CO₂ molecules under electrocatalytic conditions is crucial for gaining deeper insights into why the addition of Im-ILs can improve CO₂RR performance from a molecular perspective. Furthermore, Im-ILs can serve as both surface modifier groups and trapping agents in heterogeneous electrocatalysts, which can significantly alter the surface environment and hydrophobicity of the catalysts, leading to improved CO₂RR. Notably, the imidazolium groups present in Lehn-type and metal-porphyrin molecular catalysts have been found to have an impact on the performance of these catalysts in CO₂RR. Lastly, N-heterocyclic carbene (NHC)-based electrocatalysts, as one of the active forms of imidazolium interaction with CO₂, have demonstrated exceptional performance. When introduced into porous heterogeneous catalysts and molecular catalysts, NHC-based electrocatalysts stabilize metal nanoparticles and enhance the ability to capture CO₂, thus promoting CO₂RR activity. In summary, the utilization of imidazolium-based materials in CO₂RR holds great promise for advancing the field of CO₂ conversion and achieving more sustainable and efficient processes for high-value chemical synthesis.

Conjugated ladder polymers (CLPs) have attracted broad interest due to their intriguing optical and electronic properties. While many of these CLPs have been synthesized using solution-based reactions, on-surface synthesis under high vacuum conditions has gradually gained prominence in recent decades. This new approach holds promise for overcoming some of the limitations of conventional solution-based methods, such as the low solubility and stability of newly formed large π-conjugated systems. Azulene derivatives are attractive precursors for on-surface synthesis of CLPs that incorporate non-benzenoid moieties. The use of alkyl-substituted azulene precursors shows potential in providing CLPs with more complex backbone structures and modulated electronic properties compared to traditional CLPs that containing solely of six-membered rings. However, this strategy has been scarcely explored to date. In this study, we report on the thermal reactions of 3,3’-dibromo-2,2’-dimethyl-1,1’-biazulenyl (DBMA) on Au(111) surfaces. At room temperature, we observed that the deposited molecules formed amorphous aggregates in the fcc (face center cubic) regions of the reconstructed Au(111) surface, remaining unchanged below 100 ℃. Debromination of DBMA was induced above 150 ℃, leading to the formation of 1,1’-biazulenyl-2,2’-dimethyl-3,3’-diyls-Au organometallic polymers. These polymers exhibited complex stereostructures and distinct imaging features. At higher temperatures, the organometallic polymer underwent C―C coupling, followed by dehydrocyclization between the methyl groups and the adjacent azulene units, resulting in the ladder polymer containing benzo[a]azulene units. Interestingly, we observed that the formation of hexagonal rings between the methyl groups and the adjacent azulene units caused the polymeric chain to bend, increasing the distance between the corresponding reaction sites (methyl group and azulene) on the other side of the polymer chain. Due to the ring strain, the second ring closure did not occur within the azulene dimer as expected. Instead, this methyl group cyclized toward the other azulene unit, resulting in CLPs with a chevron shape and the absence of long-range periodicity. The evolution of related chemical species and the structures of CLPs were analyzed using scanning tunneling microscopy (STM) and bond-resolved atomic force microscopy (BR-AFM), and the reaction mechanism was discussed. This study thus demonstrates the feasibility of utilizing alkyl-substituted azulenic precursors in the synthesis of non-benzenoid carbon nanostructures on surfaces and suggests the possibility of developing two-dimensional nanostructures containing non-benzenoid units through on-surface azulene chemistry.

Directional electron transfer is an appealing strategy for harnessing photogenerated charge separation kinetics. Herein, a novel 2D/1D SnNb₂O₆/nitrogen-enriched C₃N₅ S-scheme heterojunction with strong internal electric field (IEF) and dipole field (DF) is designed through in situ growth of C₃N₅ nanorods on SnNb₂O₆ nanosheets. The IEF generated at the interface via the formation of the S-scheme heterojunction induces directional charge transfer from SnNb₂O₆ to C₃N₅. Simultaneously, the DF within C₃N₅ provides the impetus to guide photo-excited electrons to the active sites. Consequently, the synergistic effects of IEF and DF facilitate swift directional electron transfer. The optimized SnNb₂O₆/C₃N₅ heterojunction demonstrates a remarkable H₂ production rate of 1090.0 μmol·g^-1·h^-1 with continuous release of H₂ bubbles. This performance surpasses that of SnNb₂O₆ and C₃N₅ by 38.8 and 10.7 times, respectively. Additionally, the SnNb₂O₆/C₃N₅ heterojunction exhibits superior activity in the removal of Rhodamine B, tetracycline, and Cr(VI). Based on electron paramagnetic resonance (EPR), time-resolved photoluminescence (TPRL) and density functional theory (DFT) calculations, etc., the directional charge transfer mechanism was systematically explored. The research furnishes a plausible approach to construct effective heterojunction photocatalysts for applications in energy and environmental domains.

Li-O₂ batteries have garnered significant attention due to their ultrahigh theoretical energy density, comparable to that of gasoline. However, despite this promise, several challenges have hindered the commercial application of Li-O₂ batteries. These challenges include poor reversibility, unsatisfactory cycling duration, and high overpotential during battery operation. The key factor behind the poor reversibility of current Li-O₂ batteries is the occurrence of side reactions between various battery components and discharge products or intermediates. The electrolyte, an essential component in Li-O₂ batteries, plays a crucial role in charge transport and mass transfer within the battery. Among the available electrolytes used in Li-O₂ batteries, liquid organic electrolytes have been predominantly investigated as potential options. However, they suffer from insufficient chemical and electrochemical stability, which contributes to the overall poor reversibility. Substantial progress has been made in understanding the factors that lead to the degradation of liquid organic electrolytes and in enhancing their stability. However, there is still a need for more significant improvements to achieve practical performance. This review comprehensively introduces the development of liquid organic electrolytes for Li-O₂ batteries, focusing on solvents, lithium salts, and additives. It outlines the specific requirements of electrolytes for Li-O₂ batteries and highlights the importance of reducing charge overpotentials as a critical strategy to mitigate both electrochemical and chemical degradation. The review proceeds to detail the composition of liquid organic electrolytes, beginning with solvents. Carbonates, ethers, amides, and ionic liquids are discussed, along with their respective advantages, disadvantages, and strategies to overcome limitations. The role of lithium salts is then examined, with an emphasis on the relationship between the properties of lithium salts, such as donor number and anion polarity, and electrolyte performance. Some lithium salts are highlighted for their additional functions, such as forming stable solid electrolyte interfaces (SEI) on the anode side and reducing overpotential during charging. Additives in liquid organic electrolytes are also discussed. Redox mediators and singlet oxygen quenchers are discussed as representative additives, showcasing their significance in Li-O₂ batteries. Redox mediators can influence the reaction mechanism, leading to lower overpotentials in both discharge and charge processes and increased capacity. Notably, classical redox mediators like LiI are introduced, and criteria for selecting appropriate redox mediators are outlined. On the other hand, singlet oxygen quenchers convert aggressive singlet oxygen into harmless triplet oxygen, thereby suppressing unwanted side reactions in Li-O₂ batteries. The mechanism behind singlet oxygen generation is also addressed. In summary, this review aims to provide a comprehensive overview of the progress in liquid organic electrolytes for Li-O₂ batteries. It highlights the need for better electrolyte design by addressing various aspects such as solvents, lithium salts, and additives. This comprehensive understanding will guide future research efforts towards developing more stable and efficient electrolytes for Li-O₂ batteries, thereby advancing their practical applicability.

Li-ion batteries (LIBs) have been considered as one of the most promising power sources for electric vehicles, portable electronics and electrical equipment because of their long cycle life and high energy density. The free-standing electrodes without binder, current collector and conductive agent can effectively obtain lager energy density as compared to the traditional electrodes where the addition of inactive components is required. In addition, the free-standing electrode plays an important role in developing flexible electronic devices. Currently, conventional graphite is still the main commercial anode material, but its theoretical specific capacity is limited, and the rate performance is poor. In recent years, the high temperature pyrolytic hard carbon has attracted wide attention due to its higher theoretical specific capacity and more defects than graphite carbon. Moreover, polymer polyacrylonitrile (PAN) can be used as the raw material for preparation of free-standing anodes without any conductive additives or binders by electrospinning technique. Meanwhile, it is beneficial to reduce the production cost and simplify the manufacturing procedures of electrode. However, PAN-based hard carbon anode materials also have certain problems, such as low conductivity, poor rate performance, unsatisfactory cycling stability, and inferior initial Coulombic efficiency (CE). In addition, soft carbon has advantages of high carbon yield, good conductivity, superior cycling stability, high initial CE and relatively low price, but its specific capacity is generally lower than that of hard carbon materials. Based on above analysis, carbon anode materials with good electrochemical performance can be obtained by combining hard carbon and soft carbon, but the specific capacity of carbon materials is still low. Tin (Sn), as an anode material for LIBs, has a high theoretical specific capacity (994 mAh·g^-1) and a low lithium alloying voltage. Nonetheless, the practical use of Sn anode has been limited by its huge volume change (theoretically ∼260%) during the repeated alloying-dealloying process, resulting in large pulverization and cracking, which triggers the rapid capacity fading. Hence, in order to increase the specific capacity of carbon anode materials of LIBs, the C-Sn composite film with uniform Sn nanoparticles embedded in N-doped carbon nanofibers was prepared by electrospinning method following by a low-temperature carbonization process. The film was directly used as a free-standing electrode for LIBs and exhibited good electrochemical performance, and the introduction of Sn significantly improved the electrochemical properties of the carbon nanofiber film. The formed fibrous structure after Sn was uniformly coated with carbon can promote the conduction of ions and electrons, and effectively buffers the volume change of Sn nanoparticles during cycling, thus effectively preventing pulverization and agglomeration. The C-Sn-2 electrode with a Sn content of about 25.6% has the highest specific capacity and best rate performance among all samples. The electrochemical test results show that, the charge (discharge) capacity reaches 412.7 (413.5) mAh·g^-1 at a current density of 2 A·g^-1 even after 1000 cycles. Density functional theory (DFT) calculations show that N-doped amorphous carbon has good affinity with lithium, which is conducive to anchoring the Sn_xLi_y alloy formed after alloying reaction on the carbon surface, thereby relieving the volume change of Sn during charge-discharge. This article provides a feasible strategy for the design of high-performance lithium storage materials.

Gold nanorods (Au NRs) have been widely used in the optics, electricity, informatics, and biomedical fields in recent years. However, Au NRs with specialized requirements cannot be prepared by conventional methods. For instance, in photothermal therapy, Au NRs with high aspect ratios (ARs) are desirable for increasing tissue penetration and reducing the burning of human skin during treatment. However, when their ARs were adjusted to match the laser used in second near-infrared windows (NIR-II), the length and width of the Au NRs simultaneously increased. This increase in width reduces its photothermal conversion efficiency. Unfortunately, tuning the ARs of Au NRs at a fixed width requires complex procedures. In this study, we developed a new seeded-growth method to synthesize different ARs of fixed width Au NRs (FW-Au NRs). To the best of our knowledge, this is the first study to adjust the length of FW-Au NRs by introducing lauryl alcohol (LA) molecules into the traditional seeded growth method. Moreover, the length span of FW²³-Au, FW¹⁴-Au, and FW^6.5-Au NRs (the superscript numbers denote the width of Au NRs in nm) was adjusted between 130 and 38.4 nm, 109 and 26.4 nm, and 16 and 46 nm, respectively, by judiciously selecting the corresponding reaction conditions. Notably, the lengths of the Au NRs can be readily achieved at a fixed width over a wide range. In addition, their ARs were tuned at a fixed width by adjusting only their length, instead of simultaneously varying their length and width. In addition, their widths were maintained between 6.5 and 23 nm by adjusting [AgNO₃] between 0.24 and 0.30 mmol·L^-1 in the presence of LA. Furthermore, the synergetic effect of Ag⁺ and LA on the density of the cetyltrimethylammonium (CTA)-Br-Ag⁺ complexes distributed on the facets of added Au-NP seeds, which can impact their symmetry-breaking efficiency (SBE) and the particle number of Au-NP seeds that grow into final Au NRs, is key to the synthesis of FW-Au NRs. The results of this study offer a flexible and reliable method to tune the length of Au NRs with a fixed width and pave the way for achieving an on-demand synthesis of Au NRs, especially for cancer photothermal therapy.

The increasing global demand for energy and the detrimental effects of using fossil fuels highlight the urgent need for alternative and sustainable energy sources. Metal halide perovskites have gained significant research attention over the last few years, primarily for solar energy storage, light emission, and thermoelectrics, due to their low cost and high efficiency. To understand the thermoelectric transport characteristics of halide perovskites and improve their practical applications, precise knowledge of their heat transport mechanism is necessary. In this study, we used density functional theory (DFT) and different exchange-correlation functionals, namely the Perdew-Burke-Ernzerhof (PBE) and modified Becke Johnson (mBJ) schemes, to screen three inorganic halide perovskites, Rb₂SnI₆, Rb₂PdI₆, and Cs₂PtI₆, in their pristine forms for thermoelectric energy conversion. Here, we report the mechanical stability, effective masses, Seebeck coefficient, power factor, and thermoelectric figure of merit. Both PBE and mBJ functionals successfully determined the most stable geometry and accurate electronic structure for each halide perovskite. Initially, we optimized the crystal structures of all three compounds using the PBE functional and obtained the corresponding lattice parameters. The optimized lattice constants are in good agreement with the experimental values. We are the first to calculate the elastic constants and other mechanical parameters, such as the elastic moduli, Poisson's ratio, Pugh index, elastic anisotropy, and Grüneisen parameter, to determine the elastic and mechanical stability of these compounds. All three compounds (Rb₂SnI₆, Rb₂PdI₆, and Cs₂PtI₆) are mechanically stable and ductile. The effective mass of the electrons at the conduction band minimum was smaller than that of the holes at the valence band maximum. Electronic band structure calculations showed that all three compounds are narrow band gap semiconductors (with band gaps ranging from 0.47 to 1.22 eV) with degenerate band extrema. The low effective masses and favorable band gap feature make them ideal for thermoelectric applications. Our study reveals a high Seebeck coefficient of 0.76 mV·K⁻¹ for Cs₂PtI₆ for hole doping at maximum temperature. Due to the high Seebeck coefficient and maximum power factor, we found high figure of merit (ZT) of 0.98 for Cs₂PtI₆, 0.96 for Rb₂PdI₆, and 0.97 for Rb₂SnI₆, upon p-type doping. With this study, we provide new insights into the thermoelectric performance of halide perovskites and can offer inspiration for the experimental synthesis of these compounds. Our results may also contribute to developing practical energy conversion and storage devices, which can significantly affect the renewable energy sector.

Metal nanoclusters are rising stars in material science, and one advantage is their atomically precise tunability. It is well known that metal doping can efficiently modify the properties of metal nanoclusters. In particular, without altering the parent nanocluster framework, doping a single heterometal atom can tailor the properties of metal nanoclusters and aid investigations of the structure-property relationship of metal nanoclusters. To our knowledge, the simultaneous synthesis of a single heterometal-doped nanocluster and its parent nanocluster is challenging and has not been previously reported; however, this is highly desirable because it can prevent the influence of trace impurities and allow comparison between doped and undoped nanoclusters. The single Cd-doped gold nanocluster Au₂₂Cd₁(S-Adm)₁₆ (S-Adm = 1-adamantanethiolate) has been previously synthesized and structurally elucidated. However, the structure of the parent nanocluster, Au₂₃(S-Adm)₁₆, remains unknown, inspiring this investigation. In this study, we synthesized Au₂₃(S-Adm)₁₆ and its single-doped Au₂₂Cd₁(S-Adm)₁₆ nanoclusterin one pot for the first time, and we resolved their structures using single-crystal X-ray crystallography. The structure of Au₂₂Cd₁(S-Adm)₁₆ is similar to that of Au₂₃(S-Adm)₁₆ except that a kernel Au atom in Au₂₃(S-Adm)₁₆ is replaced with a Cd atom. This Cd replacement causes the kernel Au―Au bond length to increase owing to the loosening of the original closely packed structure. In contrast to prior reports, Au₂₃(S-Adm)₁₆ is surprisingly more stable than Au₂₂Cd₁(S-Adm)₁₆, as determined via ultraviolet visible-near infrared (UV-Vis-NIR) spectroscopy at 80 °C. This stability was attributed to the decrease in the kernel Au―Au bond length. Although the maximum absorption of Au₂₂Cd₁(S-Adm)₁₆ slightly red-shifted from 605 to 608 nm after Cd doping, the molar extinction coefficient of Au₂₃(S-Adm)₁₆ at 605 nm was approximately twice that of Au₂₂Cd₁(S-Adm)₁₆ at 608 nm. Thus, the increase in kernel Au―Au bond length may decrease the photoexcitation electron transfer efficiency owing to lengthening of the photoexcitation electron transfer pathway. As further support for this opinion, although the two nanoclusters showed similar emission profiles and maxima (750 nm for Au₂₃(S-Adm)₁₆ and 760 nm for Au₂₂Cd₁(S-Adm)₁₆), they exhibited obvious emission intensity differences. Specifically, the quantum yield of Au₂₃(S-Adm)₁₆ (approximately 3.160 × 10^-5) was found to be 1.13 times that of Au₂₂Cd₁(S-Adm)₁₆ (approximately 2.793 × 10^-5). Thus, the stability and absorption and emission intensities correlate with the kernel Au―Au bond length. This study shows that two metal nanoclusters with slight structural differences can exhibit different properties in terms of optical and thermal stability, providing a good reference for studying their structure-property relationships.

Photoelectrochemical water splitting using semiconductor materials is one of the most promising methods for converting solar energy into chemical energy. Among the commonly used semiconductors, p-type CuBi₂O₄ is considered one of the most suitable photocathode materials and can allow a theoretical photocurrent density of about 20 mA·cm^-2 for photoelectrochemical water splitting. However, due to severe charge carrier recombination, the obtained photocurrent density is much lower than the theoretical value. Highly efficient photoelectrochemical performance relies on fast charge carrier separation and transport, and prompt reaction kinetics. In this study, we report the development of a polyoxometalate-modified CuBi₂O₄/Mg-CuBi₂O₄ homojunction photocathode to improve both the bulk and interfacial charge carrier transport in the photocathode. For the bulk of the photocathode, the built-in electric field originating from the CuBi₂O₄/Mg-CuBi₂O₄ homojunction promotes the migration of photo-excited electrons on the conduction band from pure CuBi₂O₄ to Mg-doped CuBi₂O₄. Additionally, the electric field facilitates the transfer of holes from the valence band of Mg-doped CuBi₂O₄ to pure CuBi₂O₄. This directional transfer of both photo-excited electrons and holes plays a significant role in promoting separation and suppressing the recombination of the charge carriers. On the surface of the photocathode, the reduced polyoxometalate co-catalyst Ag₆[P₂W₁₈O₆₂] (AgP₂W₁₈) was used as a proton sponge to accelerate surface reaction kinetics and suppress carrier recombination. These synergistic effects improved the photo-generated charge carrier transfer and reaction kinetics. As a result, the novel photocathode displayed excellent photoelectrochemical properties, and the photocurrent density was observed to be -0.64 mA·cm^-2 at 0.3 V vs. RHE, which is better than that of -0.39 mA·cm^-2 for a pure photocathode. Furthermore, the novel photocathode had an applied bias photon-to-current efficiency (ABPE) higher than 0.19% at 0.3 V vs. RHE. In contrast, the pure photocathode had an ABPE of ~0.12% under the same conditions. Additionally, when H₂O₂ was used as an electron scavenger, the photocurrent density was -3 mA·cm^-2 at 0.3 V vs. RHE, which is an improvement of approximately 1.5 times compared to the pure photocathode. Furthermore, the charge separation and charge injection efficiency of the novel photocathode were significantly improved compared with the pure photocathode. The experimental results conclusively indicate that the formation of the CuBi₂O₄/Mg-CuBi₂O₄ homojunction and AgP₂W₁₈ modification played a significant role in the improved performance of the CuBi₂O₄ photocathode. The performance of the novel photocathode was comparable with the results reported in previous studies, demonstrating its promising potential in real applications.

Co-based oxides have shown promise as catalysts for the oxygen evolution reaction (OER), as evidenced by experimental and theoretical studies. However, these common Co-based catalysts suffer from poor stability in acidic environments, making them susceptible to corrosion in acid electrolytes. Consequently, developing OER catalysts that can maintain both activity and stability under strongly acidic conditions is a challenging task for large-scale industrial hydrogen production applications. To address this challenge, the incorporation of manganese (Mn) into the spinel lattice of Co₃O₄ (CoMn₁O) has been proposed, resulting in a defect-rich catalyst with improved lifetime in acidic electrolytes. The crystalline phase structures and chemical valence states were investigated using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM), and energy-dispersive spectroscopy (EDS) elemental maps. The introduction of Mn led to the generation of a significant number of defects due to changes in the local crystal structure. Additionally, as the amount of Mn atoms increased, a red shift was observed in the Co 2p spectrum, indicating an increase in the overall valence of Co and the formation of more stable Co―O bonds. Moreover, when the Mn-to-Co ratio reached 1 (CoMn₁O), the resulting catalyst exhibited promising OER activity, with overpotentials of 415 and 552 mV at 10 and 50 mA·cm^-2, respectively. Detailed physical characterization and electrochemical tests demonstrated that CoMn1O exhibited over four times the stability of Mn-free Co₃O₄ (CoMn₀O). This enhanced stability can be attributed to the introduction of Mn, which promotes electron density bias of Co towards O, resulting in the formation of more stable Co―O bonds. Mn also facilitates acidic oxygen evolution by delaying the oxidation rate of the Co active sites, thereby enhancing stability. Density functional theory (DFT) calculations were further employed to analyze the electronic structures of CoMn₁O and CoMn₀O. The d-band center of Co 3d (ε_d) in CoMn₁O shifted closer to the Fermi level (E_F) compared to that of CoMn₀O, indicating a reduced reaction energy barrier for CoMn₁O and enhanced bonding interaction with OER intermediates. Overall, this work presents a promising strategy for achieving highly efficient and stable acidic oxygen evolution using noble-metal-free electrocatalysts.

Cu-Graphdiyne and CoNiWO₄ were synthesized by organic and hydrothermal methods, respectively. The establishment of an S-scheme heterojunction between Cu-Graphdiyne and CoNiWO₄ was achieved by interface engineering design. The efficient separation and transfer of photogenerated carriers are facilitated by the synergistic effect of the built-in electric field and band bending, while maintaining the strong redox capacity of the catalysts. The introduction of Cu-Graphdiyne effectively enhances the photo absorption capacity and conductivity of the composite catalyst, and significantly suppresses the recombination of photogenerated carriers. The unique two-dimensional planar network structure of Cu-Graphdiyne provides abundant active sites for photocatalytic processes, thereby facilitating the photocatalytic reaction. Density functional theory (DFT) calculations demonstrate that hot electrons generated by surface plasmon resonance effects of Cu will transfer to Graphdiyne to promote hydrogen evolution reaction. This study offers insights into potential applications of Cu-Graphdiyne and nickel-cobalt based catalysts in photocatalytic hydrogen evolution.

Carbon dioxide (CO₂) serves as one of the major greenhouse gases in the atmosphere. However, it is also abundant, non-toxic, and renewable, making it a valuable one-carbon source. Therefore, converting CO₂ into valuable chemicals holds immense significance as an effective approach towards achieving carbon neutrality. Nevertheless, due to CO₂’s thermodynamic stability and kinetic inertness, its activation and conversion present considerable challenges. Organic carbamates, both cyclic and acyclic, represent a crucial class of bioactive compounds found in various natural products, agricultural chemicals, and pharmaceutically relevant molecules. They are also widely used as essential intermediates in organic synthesis. Unfortunately, traditional methods for preparing organic carbamates often rely on highly toxic phosgene and its derivatives as raw materials, posing serious environmental and safety concerns and limiting practical applications. From a cost-effective and sustainable standpoint, substituting CO₂ for phosgene in the synthesis of organic carbamates is highly appealing. In recent decades, numerous new reactions, particularly multicomponent reactions involving CO₂ and amines, have emerged, providing efficient methods for constructing diverse and valuable carbamates. Some of these reactions can be conducted under transition-metal-free conditions, utilizing organic and inorganic bases, ionic liquids, or small organic molecules as catalysts or promoters. However, in certain cases, transition-metal catalysts, such as those based on copper, palladium, or silver, are required, especially when the reactions involve activating unsaturated hydrocarbons like alkenes and alkynes. Mechanistically, most of these methods involve in situ generation of nucleophilic CO₂-amine adducts, such as carbamate salts or carbamic acids, which then react with other electrophiles or coupling partners to yield the desired carbamates. Notably, recent advancements have led to the successful development of several elegant methods for synthesizing specific types of carbamates using electrocatalysis or photocatalysis, which are not achievable through conventional thermal catalysis. This review comprehensively summarizes the recent progress in the synthesis of organic carbamates using CO₂ and amines under various catalytic conditions, including transition metal-free conditions, transition metal-catalysis, electrocatalysis, and photocatalysis. Additionally, the review discusses the challenges and future prospects associated with converting CO₂ into organic carbamates.

Cholesteric liquid crystal (CLC) microdroplets, as three-dimensional photonic crystals, exhibit high spatial symmetry. In these microdroplets, LC molecules are aligned parallel to the surface of the spherical geometry, while the helical axes are radially oriented. This symmetrical helical superstructure arrangement forms a Bragg-onion structure within the CLC microdroplets, resulting in selective reflection of a specific wavelength in all directions. Due to their unique angle-independent photonic bandgap (reflection wavelength), CLC microdroplets have emerged as promising optical materials for applications such as omnidirectional lasers, reflective displays, and microsensors. Recently, there has been growing interest in capillary microfluidic technologies, which allow the fabrication of monodisperse and complex CLC microdroplets with regular molecular alignment in a continuous, controllable, and high-throughput manner. This review primarily focuses on CLC microdroplets fabricated using capillary microfluidic technologies. Firstly, the characteristics of capillary microfluidic technology are outlined, along with three important parameters for fabricating CLC microdroplets: inertial, viscous, and interfacial forces. Capillary microfluidic devices typically consist of hydrophilic or hydrophobic tapered capillaries inserted into a square capillary. The principle of immiscible liquids is utilized to select suitable solution systems. By designing the device structures and choosing appropriate solution systems, single, double, triple, and even multiple CLC microdroplets can be fabricated. Secondly, the optical properties of CLCs confined in spherical geometries are discussed. CLC self-organizes into ordered helical superstructures while maintaining fluidity, leading to symmetrical pitch lengths in CLC microdroplets that respond to stimuli. The mechanisms and strategies for tuning the structural colors of CLC microdroplets under varying temperatures, solvents, and light conditions are demonstrated. Additionally, the unique photonic cross-communication between closely packed, monodisperse CLC microdroplets is explained in the context of single, double, or opposite-handedness helical superstructures in CLCs. Furthermore, the review reports on the current and prospective applications of CLC microdroplets in omnidirectional lasers, reflective displays, and microsensors. Various methods for inducing lasing in CLC microdroplets are presented, including distributed feedback resonators, Bragg reflection resonators, and whispering gallery modes. Flexible reflection labels and security labels are generated by incorporating different materials in each layer of the microdroplets or by leveraging the unclonable photonic cross-communication micropatterns observed in hexagonally close-packed CLC microdroplets. The responsive pitch lengths and molecular alignments of CLC microdroplets also make them suitable candidates for colorimetric reporters and optical biosensors. Finally, the review briefly discusses the existing challenges and opportunities in the field of CLC microdroplets, offering a forecast for future developments.

Near-neutral zinc-air batteries show great promise for long-cycle applications in ambient air owing to their impressive deposition/stripping compatibility with zinc anodes and greater chemical stability towards CO₂ in ambient air compared to batteries with traditional alkaline electrolytes. However, the inherent water volatilization of liquid electrolytes and the flexibility of electrolytes required for wearable devices severely limit the practical application of this system. In this study, a fumed SiO₂-based composite hydrogel polymer electrolyte (SiO₂-HPE) was prepared for application in near-neutral zinc-air batteries. The design of the SiO₂-HPE was carried out considering the following three aspects. Firstly, it is widely acknowledged that the polyacrylamide polymer skeleton is beneficial to excellent ionic conductivity and the mechanical strength of the SiO₂-HPE. Secondly, fumed SiO₂ bearing multiple silicon hydroxyl groups is a suitable option as a water-retaining additive. Thirdly, the near-neutral liquid electrolyte (1 mol·kg^-1 Zn(OTf)₂) absorbed in the SiO₂-HPE is stable towards CO₂ in ambient air. In conclusion, these three aspects of the electrolyte design contribute to the practical application of the SiO₂-HPE. Raman spectroscopy and scanning electron microscopy revealed that the synthesized SiO₂-HPE exhibited a high degree of polymerization, plentiful surface pores, and a uniform distribution of elements. According to the infrared and Raman spectra, the abundant hydroxyl groups located on the surface of the SiO₂ particles enhanced water molecule binding by altering the hydrogen bond network within the SiO₂-HPE. This conclusion was further confirmed by thermogravimetry and differential scanning calorimetry. After exposure to ambient air (30% relative humidity) for 96 h, the SiO₂-HPE exhibited a water retention capacity of 49.52%, which is 6.23% and 1.73% higher than those for 1 mol·kg^-1 Zn(OTf)₂ and the HPE (hydrogel polymer electrolyte without SiO₂). Moreover, owing to the dynamic recombination of the hydrogen bonds between the silicon hydroxyl groups and the gel skeleton, SiO₂-HPE exhibited a higher mechanical strength and modulus than HPE under tensile and compressive conditions, respectively. This further rendered it an ideal electrolyte for flexible zinc-air batteries. The near-neutral zinc-air battery assembled with the SiO₂-HPE exhibited a cycle life of up to 200 h under 30% relative humidity, far exceeding those of 1 mol·kg^-1 Zn(OTf)₂ and the HPE. Based on such remarkable performance, the flexible near-neutral zinc-air battery device assembled by the SiO₂-HPE has shown a satisfactory performance under special conditions, such as bending and cutting, and can be used as a power supply for different electronic devices, making it a promising next-generation electrochemical energy storage device. Overall, this work provides new insight into the development of flexible zinc-air battery devices with long-term stability in ambient air.

Metal-organic frameworks (MOFs) as efficient electrocatalysts can be employed as the promising cocatalysts in photoelectrochemistry. Herein, a strategy is developed to metal-organic frameworks as oxygen evolution cocatalyst (OEC) combined with semiconductor for improving the charge transport and reducing the bulk/surface carrier recombination. This advanced CoFe MOF/BiVO₄ photoanode exhibits a photocurrent density of 4.5 mA·cm^-2 at 1.23 V (vs. RHE) under AM 1.5G illumination, achieving outstanding long-term photostability. Remarkably, with the reconstruction of MOF in the long-term water oxidation reaction, more stable metal oxyhydroxides are formed on the surface of BiVO₄ and the photocurrent density of the photoelectrode is further enhanced to 5 mA·cm^-2. From density functional theory calculations, the enhanced photoelectrochemical (PEC) performance can be attributed to the coupling effect between Co and Fe decreasing the free energy barriers and accelerating the reaction kinetics. This work focuses on the reconfiguration of CoFe MOF catalyst to bimetallic hydroxide during long-term water oxidation. This work enables us to develop an effective pathway to design and fabricate efficient and stable photoanodes through MOFs catalysts for feasible PEC water splitting.

Urea electrolysis is critically important for the advancement of sustainable and clean energy conversion technologies, addressing global energy shortages and environmental concerns. The urea oxidation reaction (UOR) poses a significant challenge due to its unfavorable thermodynamics, making it a pivotal step in urea splitting. The 6-electron transfer process of UOR presents a bottleneck due to its sluggish kinetics. Consequently, the development of efficient urea oxidation electrocatalysts and gaining insights into the electronic configuration of the central metal ion are of paramount significance in achieving high-performance urea-based energy conversion technologies. In this study, we report the successful synthesis of hierarchical Ni₂P nanosheets@nanorods (P-Ni₂P HNNs) as promising catalysts to enhance UOR efficiency. This catalyst is designed and constructed using a hexamethylenetetramine-hydrolytic coprecipitation-oxidation process and a straightforward phosphorus-substituted method. X-ray absorption fine structure spectroscopy indicates that the presence of P-modified metal centers is responsible for the elevated UOR activity of P-Ni₂P HNNs, with the electronic structure of Niⁿ⁺ significantly enhancing Ni―O―O bond coupling for rapid UOR kinetics. Thanks to the highly exposed Niⁿ⁺ centers and the well-designed architecture, P-Ni₂P HNNs exhibit superior UOR activity and stability, with a low overpotential of 132 mV at 10 mA∙cm⁻², a small Tafel slope of 33.7 mV∙dec⁻¹, and sustained durability for 6 h at 10 mA∙cm⁻². Furthermore, a two-electrode cell for overall urea electrolysis is assembled with a P-Ni₂P HNNs-2/NF anode, yielding a low potential of 1.411 V at 10 mA∙cm⁻² and a high current density of 100 mA∙cm⁻² at 1.595 V. This study presents an effective and viable approach for designing and synthesizing high-efficiency nickel-based phosphide electrocatalysts, which could pave the way for cost-effective and energy-efficient electrochemical hydrogen production, and advance phosphide research for various energy-related applications.

This study focuses on exploring efficient photocatalysts for water splitting, which holds great potential for harnessing hydrogen (H₂) as a renewable energy source. Modulating the heterojunction interface is known to enhance charge carrier separation and solar energy utilization, thereby boosting photocatalytic activity. In this work, a mechanical mixing-assisted self-assembly approach was developed to construct a heterojunction between NiPS₃ (NPS) nanosheets (NSs) and C₃N₅ (CN) NSs. Specifically, two-dimensional (2D) NPS NSs were tightly deposited on 2D CN NSs surface to gain a 2D/2D heterostructure. The photocatalytic performance of the synthesized photocatalysts was determined by their ability to generate H₂ through water splitting, both in deionized (DI) water and seawater, under visible light. The resulting NPS NSs/CN NSs (NPS/CN) composites possessed boosted photocatalytic hydrogen evolution (PHE) activity related to CN NSs and NPS NSs. This improvement was assigned to the synergistic effect of increased light-harvesting capacity and heterojunction formation. Nevertheless, an excessive amount of deposited NPS NSs on the surface of CN NSs was found to reduce the light absorption of the CN NSs component in the NPS/CN composites, resulting in decreased PHE activity. Therefore, it was determined that an appropriate mass ratio between the two components is necessary to achieve excellent photocatalytic activity for the NPS/CN composites. The optimized photocatalyst, referred to as 3-NPS/CN, demonstrated the highest visible-light-driven PHE efficiency of 47.71 μmol·h^-1, which was 2385.50 times higher than that of CN NSs. Moreover, 3-NPS/CN also exhibited excellent PHE activity in seawater, with a rate of 8.99 μmol·h^-1. The photoelectrochemical, steady-state photoluminescence (PL), time-resolved PL (TR-PL), steady-state surface photovoltage (SPV) and time-resolved surface photovoltage (TPV) techniques were performed to investigate the charge separation and migration behaviors of various photocatalysts. Based on the characterization results, our group proposed a reasonable PHE mechanism. In the NPS/CN photocatalysts, photo-induced electrons rapidly migrated from the conduction band (CB) of CN NSs to the CB of NPS NSs due to the potential difference and strong interfacial electronic coupling between the two materials. The photogenerated electrons accumulated on the CB of the NPS NSs component efficiently reduced protons to generate H₂ molecules. Concurrently, photogenerated holes on the valence band (VB) of CN NSs and NPS NSs were consumed with the assistance of triethanolamine (TEOA) molecules. This study presents a facile method for fabricating 2D/2D heterostructured photocatalysts, which hold promise for efficient and robust implementation in energy applications.

Lithium metal is a promising anode candidate for high-energy-density secondary batteries due to its high theoretical capacity and low electrochemical potential, while the uncontrolled dendrite growth causing poor cycling performance and safety concerns poses serious challenges for the practical application of lithium metal batteries. During the electrodeposition process, the lithium-ion (Li⁺) diffusion process is directly related to the electrode/electrolyte interfacial Li⁺ concentration gradient as well as the dendritic morphology. Regulating the anisotropic Li⁺ diffusion property is a convenient way to reshape its transfer behavior without introducing any external fields (e.g., temperature field, magnetic field, acoustic field, etc.) or increasing the weight of batteries. Despite the large amount of experimental and theoretical work on the effect of the anisotropic Li⁺ diffusion behavior on the dendritic morphology, some open questions remain to be deliberated, e.g., correlating the dynamic evolution of dendrite growth with the anisotropic Li⁺ diffusion induced by the electrolyte property, electric potential, and separator structure. In this paper, an electrochemical phase-field model is applied to explore the influences of electrolyte inherent anisotropic Li⁺ diffusion, electric potential-induced anisotropic Li⁺ diffusion, and separator-structure-induced anisotropic Li⁺ migration on dendrite growth via a homemade MATLAB code. Instead of a fixed numerical value, the modified Li⁺ diffusivity in the electrolyte (D_L) is expressed as a second-order tensor by decomposing into two components along the x (D_xx) and y (D_yy) directions, which is not only able to explore the electrolyte inherent anisotropic Li⁺ diffusion but also easy to describe the electric potential-induced fluctuations of D_L and the corresponding Li⁺ concentration distribution. Predicted results indicate that with the increase of D_yy: D_xx, the interfacial Li⁺concentration gradient is alleviated due to the accelerated longitudinal Li⁺ replenishment and decelerated transversal “entrainment” phenomenon, thus decreasing the driving force of dendrite growth. Besides, the electric potential-induced interfacial Li⁺ fast diffusion layer can also reduce the electric potential gradients surrounding the dendrite tips and then uniform the dendrite morphologies. Surprisingly, separators with higher matrix tilt angles are demonstrated to achieve effective anisotropic Li⁺ diffusion in electrolyte, which can not only reduce the dendrite-growth velocity, but also extend the dendrite-growth pathway and prolong the battery short circuit time. Following this, electrolyte with the D_yy: D_xx = 10: 1 and separator with the matrix tilt angle of arctan (0.5) are evaluated as promising materials for lithium metal batteries. This study provides a rational guidance for designing electrolytes or separators with dendrite-inhibiting capability.

Electrochemical oxygen reduction reaction via the two-electron pathway (2e-ORR) is becoming a promising and sustainable approach to producing hydrogen peroxide (H₂O₂) without significant carbon footprints. To achieve better performance, most of the recent progress and investigations have focused on developing novel carbon-based electrocatalysts. Nevertheless, the sophisticated preparations, decreased selectivity and undefined active sites of carbon-based catalysts have been generally acknowledged and criticized. To this end, transition metal oxides and chalcogenides have increasingly emerged for 2e-ORR, due to their catalytic stability and tunable microstructure. Here, the development of metal oxides and chalcogenides for O₂-to-H₂O₂ conversion is prospectively reviewed. By summarizing previous theoretical and experimental efforts, their diversity and outstanding catalytic activity are firstly provided. Meanwhile, the topological and chemical factors influencing 2e-ORR selectivity of the metal oxides/chalcogenides are systematically elucidated, including morphology, phase structures, doping and defects engineering. Thus, emphasizing the influence on the binding of ORR intermediates, the active sites and the underlying mechanism is highlighted. Finally, future opportunities and challenges in designing metal oxides/chalcogenides-based catalysts for H₂O₂ electro-synthesis are outlined. The present review provides insights and fundamentals of metal oxides/chalcogenides as 2e-ORR catalysts, promoting their practical application in the energy-related industry.

Graphite has been extensively employed as commercial anode material in Li-ion batteries due to its high abundance, low cost, and negative electrode potential. Furthermore, it has demonstrated significant potential for use in K-ion batteries. However, distinct structural damage caused by the larger radius of K-ion (0.138 nm) compared to that of Li-ion (0.076 nm) leads to obvious capacity decay and unstable cycle life. It is crucial to improve the cycling stability of graphite in potassium ion batteries (PIBs). Herein, we design a stable interface of graphite anode by graphene coating with a simple and efficient microwave method. According to X-ray photoelectron spectroscopy (XPS), microwave reduction can effectively remove the oxygen group of graphene oxide (GO) within 10 s. The graphene coating can buffer the volume expansion of the graphite to suppress structural collapse; it can also accelerate electronic transmission to improve rate performance. As a result, the graphene-coating graphite anode, named GCG, exhibits super cycling stability with a capacity of 262 mAh∙g^-1after 3000 cycles at a current density of 0.2 A∙g^-1, which means it can operate smoothly for one year. In contrast, at the same current density, graphite exhibits capacity fading to less than 150 mAh∙g^-1 after 150 cycles. Moreover, compared to graphite, GCG demonstrates better rate performance achieving a capacity of 161.2 mAh∙g^-1 at 500 mA∙g^-1. Further electrochemical impedance spectroscopy (EIS) and galvanostatic intermittent titration technique (GITT) tests show that GCG exhibits faster electrical conductivity and ion diffusion compared to graphite. Raman spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) images after cycling verify that the graphene buffer interface benefits the integrity of the electrode structure and improves the stability of the solid electrolyte interphase (SEI). Compared to graphite, the GCG anode exhibits better performance, as follows: 1) The graphene coating inhibits exfoliation of graphite during cycling, solving the problem of graphite anode’ short cycling life, and 2) the graphene protective layer improves the ion diffusion rate, resulting in better rate performance of the GCG. In addition, this approach offers the advantages of simple operation and low cost, hopefully enabling large-scale applications of potassium-ion batteries.

The continuous increase in the consumption of coal, oil, and natural gas has not only led to the depletion of unsustainable energy sources, but has also caused excessive CO₂ emissions, thus resulting in serious energy crises and climate issues. In such a scenario, it is imperative to explore clean and sustainable energy conversion technologies to address the escalating energy demands and environmental crises. Photocatalytic CO₂ conversion, inspired by natural photosynthesis, utilizes solar energy to convert CO₂ and water into valuable chemicals. After decades of development, artificial photosynthesis has emerged as a green, cost-effective, and sustainable approach to achieving carbon neutrality. However, the challenges of low carrier separation efficiency and insufficient active sites in photocatalysts remain significant hurdles in achieving high-performance CO₂ photoreduction. To address this challenge, the integration of metal nanoparticles with semiconductors to create an Ohmic junction can enhance electron-hole migration by the assist of interfacial electric field (IEF). In this study, an Ohmic junction photocatalyst is constructed by in situ formation of Bi nanoparticles on the surface of BiOCl nanosheets through a solvothermal process. The composition and morphology of the photocatalysts were analyzed using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS) was employed to assess the light absorption performance of the photocatalyst. Transient photocurrent response, electrochemical impedance spectroscopy (EIS), and electron spin resonance (ESR) were utilized to evaluate the efficiency of electron-hole transfer. The distinct work function difference between Bi nanoparticles and BiOCl nanosheets leads to favorable charge transfer characteristics within the formed Ohmic junction, significantly improving the utilization efficiency of photogenerated carriers. Besides, the Bi nanoparticles serve as co-catalysts, enhancing the activation of inert CO₂. As a result, the optimized Bi/BiOCl composite (Bi/BiOCl-2) exhibits enhanced generation rates of CO (34.31 µmol·g^-1) and CH₄ (1.57 µmol g^-1) during 4-h of irradiation, which is 2.55 and 4.76 times compared to pristine BiOCl nanosheets, respectively. Isotope tracer experiments suggest that the obtained carbon-based products are generated through CO₂ photoreduction in the presence of water molecule under irradiation. Moreover, in situ Fourier-transform infrared spectroscopy (in situ FTIR) results indicate the formation of *CHO, *CH₃O, b-CO₃^2-, m-CO₃^2-, HCO^-₃, HCOOH, *COOH, and HCOO^- species during the CO₂ reduction process and a possible mechanism for CO₂ photoreduction into CO and CH₄ is proposed based on these findings. After 25-h of CO₂ photoreduction reaction, the yields of CO and CH₄ continue to increase. Furthermore, the stability of the prepared material is confirmed by XRD pattern, XPS analysis, and TEM image. These outcomes underscore an effective strategy for constructing advanced photocatalysts tailored for high-performance solar-driven CO₂ reduction.

The construct of the internal electric field (IEF) is recognized as an effective driver for promoting charge migration and separation to enhance photocatalytic performance. In this study, one-dimensional nanorods of Mn_0.2Cd_0.8S (MCS) co-doped with interstitial chlorine (Cl_int) and substitutional chlorine (Cl_sub) were designed and synthesized using a one-step solvothermal method. The incorporation of Cl_int and Cl_sub led to an unbalanced charge distribution and the formation of IEF in the MCS nanorods, contributing to the improvement of photogenerated carrier kinetic behavior. Through density functional theory (DFT) calculations, the effect of Cl_int and Cl_sub doping on the activity of the MCS was visually explained by examining differences in electronic structure, charge distribution and H₂ adsorption/desorption balance. Interestingly, the modulation of the energy band structure of MCS primarily resulted from the contribution of Cl_int, while Cl_sub playing a negligible role. Moreover, the Cl_sub further facilitated the optimization of Cl_int concerning the H₂ adsorption-desorption Gibbs free energy (ΔG_H^*) of MCS. Ultimately, the ΔG_H^* of 0.9 Cl-MCS favored H₂ production (1.14 vs. 0.17 eV), leading to a 9 times increase in photocatalytic H₂ production activity compared to MCS. This investigation presents a valuable approach for constructing IEF in bimetallic sulfide photocatalysts.

The Li/CrO_x battery has gained attention in the construction of smart cities, aerospace, and national defense and military applications due to its high energy density and excellent rate performance. Developing a Li/CrO_x battery with high specific capacity, high energy density, excellent magnification performance, long storage life, and low cost is a primary goal. In this pursuit, the role of the electrolyte in battery performance for Li/CrO_x primary batteries cannot be underestimated. However, current research on Li/CrO_x primary batteries has primarily focused on electrode materials, with limited attention given to the electrolyte. Propylene carbonate (PC) solvent possesses a wide temperature range for melting and boiling points (−48.8 to 242 °C) and a high dielectric constant of 64.92. As a result, it is frequently used as a key component in electrolytes that operate under extreme temperatures and high rates. Nevertheless, its use in Li/CrO_x batteries remains limited. Developing electrolyte systems based on PC with a wide temperature range and high dielectric constant is crucial for the advancement of high-power and environmentally robust lithium primary batteries. In this study, we investigated the discharge behavior of CrO_x in PC-based electrolytes and identified suitable electrolyte systems for high-current discharge, specifically a 1 mol∙L⁻¹ LiTFSI PC : DOL (1,3-dioxolane) = 1 : 2 ratio. We also demonstrated that the coordination number of solvent molecules in the solvation sheath layer around Li⁺ ions and the solvated structure involved in coordination significantly influence the rate performance of Li/CrO_x battery systems in PC-based electrolytes. Reducing the coordination number of solvent molecules facilitates the desolvation behavior of solvated Li⁺, thereby enhancing the desolvation process on the material surface. Furthermore, lowering the coordination number of solvent molecules promotes the involvement of anions in the solvated sheath structure. When the coordination number of solvent molecules falls below 3, it tends to form a solvated coordination structure involving anions with a higher lowest unoccupied molecular orbital (LUMO) level. This enables anions to participate in forming a solid electrolyte interface (SEI), resulting in a thinner and denser SEI film that significantly improves battery performance. Ultimately, modifying the coordination number for PC-based electrolytes is a practical and effective approach to enhance the rate performance of solvated sheath structures. The coordination number and the solvated sheath structure of Li⁺ in PC-based electrolytes have a profound impact on the high-current-discharge performance of the Li/CrO_x battery system. A lower coordination number and the participation of anions in the solvated sheath structure effectively accommodate the high-rate discharge characteristics of the Li/CrO_x battery. Among several selected electrolyte solvents, an electrolyte with DOL (a cyclic ether) and PC reduces the solvent’s coordination number to less than four, thereby enabling high-rate discharge. Understanding these principles is crucial for advancing the application of PC-based electrolytes in high-rate Li/CrO_x battery systems.

Owing to its high energy density, sustainability, and pollution-free combustion, hydrogen is considered one of the most promising emerging energy carriers to replace conventional fossil fuels. Among the various hydrogen production technologies, electrolytic water splitting has gained significant attention thanks to its high efficiency and environmentally friendly characteristics. However, the large-scale application of electrolytic water splitting is often hindered by the limitations imposed by the anodic oxygen evolution reaction (OER). To overcome this challenge, a promising alternative approach is to replace the OER with the electrocatalytic glycerol oxidation reaction (GOR) at the anode. This substitution can lead to energy savings and enhanced efficiency of electrolytic water splitting for hydrogen production, thereby further promoting the development of hydrogen as a clean energy source. However, the application of the GOR at anode requires efficient, cost-effective, and highly selective electrocatalysts. To this end, we report the development of a novel acid-alkaline dual-electrolyte flow electrolyzer (AADEF-electrolyzer) by coupling the GOR at the alkaline anode with the hydrogen evolution reaction (HER) at the acidic cathode. A self-supported NiCo₂O₄ nanoneedle electrode material (NiCo₂O₄/NF) has been in situ grown on nickel foam (NF) using a simple hydrothermal-calcination method. The electrode demonstrates excellent electrocatalytic performance for the GOR, achieving high electrolysis current density at low potentials and exhibiting high selectivity for formate production, with the Faraday efficiency exceeding 85%. Density functional theory (DFT) calculations imply that NiCo₂O₄ has a lower energy barrier for the reaction and that the presence of Ni facilitates the reduction of the Co state density, thereby promoting the GOR. An innovative AADEF-electrolyzer was constructed by utilizing NiCo₂O₄/NF as the anode for the GOR and an acidic cathode for the HER. Experimental results indicate that the AADEF-electrolyzer exhibits excellent GOR performance with a low overpotential and high selectivity toward formate production. It requires a voltage of only 0.36 V to achieve a current density of 10 mA·cm^-2 and long-term stability with a Faraday efficiency close to 100% for hydrogen production. The low-cost and easily fabricated self-supported electrode material, together with the acid-alkaline dual-electrolyte flow electrolyzer, provide an innovative strategy for developing hybrid electrolysis systems.

Improving the thermal stability, chemical stability, and mechanical strength of battery separators is crucial to prevent safety incidents like thermal runaway in batteries. This significantly enhances the overall safety performance of batteries. Among various options, polyimide (PI) stands out as an ideal choice due to its outstanding thermal stability, excellent chemical stability, and high mechanical strength. However, existing preparation methods of PI separators, such as non-solvent induced phase separation (NIPS), template method, and electrospinning, often suffer from issues like inadequate mechanical strength. Therefore, this study focused on investigating a novel method to prepare thermoplastic PI porous films with thermally closed pores and enhanced mechanical strength. Several characterization techniques, including scanning electron microscopy (SEM), in situ Fourier transform infrared spectroscopy (FTIR), and thermal gravimetric analyzer (TGA)-FTIR coupling, were employed to understand the pore-forming mechanism of PI porous films. The findings revealed that the temperature range of triethylamine (TEA) removal was consistent with the main stage of the imidization reaction and pore formation. This indicated that the pore structure was formed in situ during the thermal imidization process when TEA was stripped out of the PI film. PI films with varying TEA contents were prepared to investigate the impact on pore structure, showing that pore size could be regulated by TEA content. A more regular reticulated small pore structure on the macroporous pore wall was observed when TEA content was ≥ 100%. SEM analysis showed that the films were thermally self-closed at a heat treatment temperature of 300 °C. Additionally, TGA indicated that the thermal decomposition temperature of PI porous film reached 580 °C. The mechanical strength of the PI films before and after pore closure was investigated, demonstrating excellent mechanical strength of approximately 120 MPa. The novel in situ pore formation method for PI porous films through the salt-formation method of poly (amic acid) (PAA) with the organic base TEA, followed by TEA release during thermal imidization, resulted in PI porous films with outstanding thermal stability and high mechanical strength. The self-closure of the PI porous film at high temperatures effectively isolates material and heat transport, providing robust safety assurance for batteries. This advancement has the potential to significantly improve battery safety and performance.