物理化学学报

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调控单位点M-N-C电催化剂的电子结构提升二氧化碳还原性能

唐甜蜜, 王振旅, 管景奇   

  1. 吉林大学化学学院, 物理化学研究所, 长春 130021
  • 收稿日期:2022-08-24 修回日期:2022-09-05 录用日期:2022-09-08 发布日期:2022-09-14
  • 通讯作者: 管景奇 E-mail:guanjq@jlu.edu.cn
  • 基金资助:
    国家自然科学基金(22075099)与吉林省教育厅(JJKH20220967KJ,JJKH20220968CY)资助项目

Electronic Structure Regulation of Single-Site M-N-C Electrocatalysts for Carbon Dioxide Reduction

Tianmi Tang, Zhenlu Wang, Jingqi Guan   

  1. Institute of Physical Chemistry, College of Chemistry, Jilin University, Changchun 130021, China
  • Received:2022-08-24 Revised:2022-09-05 Accepted:2022-09-08 Published:2022-09-14
  • Contact: Jingqi Guan E-mail:guanjq@jlu.edu.cn
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (22075099) and the Education Department of Jilin Province, China (JJKH20220967KJ, JJKH20220968CY).

摘要: 全球的动力来源主要依靠化石能源,然而无节制地开采引起了一系列的能源危机和环境问题,例如,能源枯竭、气温逐年升高、气候恶化和海洋酸化等,这已经威胁了人类的可持续发展,因此寻找可再生能源和减缓二氧化碳的排放成为目前的关键问题,反应条件相对温和的电催化二氧化碳还原反应(CO2RR)可将CO2转化为具有工业价值的产品,例如C1、C2和C2+,这是解决“碳中和”的一种有效措施。电催化CO2RR是一个复杂的多个电子/质子转移过程,反应机理相对复杂,涉及很多反应中间体,影响产物的选择性,CO2RR的大规模应用需要开发低成本和高效的电催化剂。具有大比表面积、100%的原子利用率、不饱和配位、相对均匀的活性位点的原子分散的金属和氮共掺杂碳(M-N-C)材料是一种很有前途的催化剂。M-N-C材料具有可调变性,通过调节中心金属离子或中心金属离子的配位环境,中心金属离子的电子性质和原子结构将会发生变化,这为设计具有高效催化CO2性能的催化剂提供了新的途径。因此,探讨在原子水平上调控M-N-C材料的电子结构对其在催化CO2RR活性和选择性的影响上具有重要意义。此外,CO2的大多数产物的半反应的还原电位在析氢反应的±0.2 V范围内,而且大多数与CO2结合的催化剂都富含电子,对析氢反应有活性。因此在设计催化剂时还需要考虑抑制竞争性析氢反应的进行。本文我们总结了M-N-C材料合成方法、CO2还原成C1、C2和C2+的反应路径以及影响CO2RR的主要因素。主要系统地总结了三种调控M-N-C材料电子结构和几何构型的策略,即修饰M-N-C材料的碳基面、选择合适的中心金属离子和调节中心金属离子的配位环境,并详细的讨论了在不同活性位点上对催化CO2RR中各种产物选择性的影响。最后,我们提出了目前M-N-C材料在电催化CO2RR中的应用所面临的挑战和未来的发展方向。

关键词: M-N-C材料, 单位点催化剂, 电子结构, 配位环境, 吉布斯自由能

Abstract: The current global population and economy depends on fossil fuel consumption; however, the uncontrolled exploitation of fossil fuels has caused a series of energy crises and environmental problems, such as energy exhaustion, annual temperature rise, climate deterioration, and ocean acidification, which have already threatened the sustainable development of all living organisms. Therefore, finding renewable and reliable energy sources as well as reducing carbon dioxide (CO2) emissions have become the key focus in recent years. During the electrocatalytic CO2 reduction reaction (CO2RR) under relatively mild conditions, CO2 is converted into valuable products, such as C1, C2, and C2+ hydrocarbons, which is an effective strategy towards realizing "carbon neutrality". Electrocatalytic CO2RR is complex as it involves multiple electron/proton transfer processes. The reaction mechanism is also complex and involves many intermediates, which ultimately affects product selectivity. The large-scale application of the CO2RR requires the development of cheap and efficient electrocatalysts. Atomically dispersed metal and nitrogen co-doped carbon (M-N-C) materials, with large surface areas, 100% atomic availability, unsaturated coordination, and relatively uniform active sites, are promising catalysts for the CO2RR. M-N-C materials also have adjustable properties. For example, tuning the coordination environment of the central metal ions changes the electronic properties and atomic structures of the metal ions, which provides a new way for designing catalysts with high CO2RR performances. Therefore, it is of great significance to investigate the effect of regulating the electronic structure of M-N-C materials at the atomic level on catalytic activity and selectivity during the CO2RR. Additionally, the reduction potentials of the half reactions of most CO2RR products are within ±0.2 V of the hydrogen evolution reaction (HER), and most catalysts that bind CO2 are rich in electrons and active for the HER. Therefore, it is also necessary to design catalysts that can kinetically inhibit the competitive HER during the CO2RR. In this review, we discuss the synthesis methods of M-N-C materials, the reaction pathways of CO2 reduction to C1, C2, and C2+ hydrocarbons, and the main factors affecting the CO2RR. Specifically, three strategies for regulating the electronic structures and geometric configurations of M-N-C materials are systematically reviewed, namely, the modification of the carbon base surface of M-N-C materials, selection of appropriate central metal ions, and regulation of the coordination environment of the central metal ions. The effects of different active sites on the selectivity towards various products during the catalytic CO2RR are also discussed in detail. Finally, we highlight the current challenges and future development directions of M-N-C materials for the electrocatalytic CO2RR.

Key words: M-N-C material, Single-atom catalyst, Electronic structure, Coordination environment, Gibbs free energy

MSC2000: 

  • O643