New membrane matrices used in ion selective electrodes, such as polyacrylate, vinyl resin, silicone rubber, polyurethane, and conducting polymer without or with a reduced amount of plasticizer, are systematically summarized based on the latest literature. Physical and chemical properties of these membrane martrices, as well as their resultant potentiometric sensor performance, are reviewed thoroughly. It is pointed out that these new sensing membrane matrices not only avoid plasticizer leakage that would contaminate biological samples, but also reduce the diffusion coefficients of these sensing membranes by about 3 orders of magnitude, which is very helpful to suppress the ion flux. The lower diffusion coefficient results in falling of a lower detection limit by 5 orders of magnitude compared to the traditional plasticized PVC sensing membrane. At the same time, the selectivity coefficients have also been improved. In addition, these new materials have excellent adhesion properties with solid support materials, which ensure long lifetimes of the ion selective electrodes, especially in solid state electrodes. Unique new potentiometric sensors based on these new sensing membrane materials without or with reduced amounts of plasticizer could play an important role in many areas such as environmental monitoring and food safety, and would be especially useful in medical diagnosis and detection of biomaterials.

High pressure vapor-liquid equilibrium data for the carbon dioxide + dimethyl carbonate (DMC) binary system were measured at four temperatures in the 333.0 to 393.0 K range and under pressures ranging from 3.98 to 13.75 MPa. The experimental data were correlated with the Peng-Robison (PR) cubic equation of state and the van der Waals-1 mixing rule. The binary interaction parameters were also obtained. The agreement between experimental results and calculations was good.

The heat capacities of rare earth complexes, Nd(Gly)₂Cl₃·3H₂O and Pr(Ala)₃Cl₃·3H₂O were measured with a high-precision automatic adiabatic calorimeter in the temperature range from 80 to 357 K for Nd(Gly)₂Cl₃·3H₂O, and from 80 to 374 K for Pr(Ala)₃Cl₃·3H₂O. The thermodynamic functions (H_T?H_298.15) and (S_T?S_298.15) relative to the reference temperature 298.15 K of the two compounds were calculated based on experimental heat capacity data. Possible mechanisms of thermal decompositions were proposed according to the thermogravimetric (TG) analysis. Based on the measurements of dissolution enthalpies using a solution-reaction isoperibol calorimeter, the standard molar enthalpies of formation were calculated in terms of a designed Hess thermochemical cycle.

Zinc oxide (ZnO) is a multifunctional material with wide applications in chemical engineering.Hydrothermal synthesis of ZnO under supercritical conditions from salt solutions containing zinc ions is an environmentally safe process. Two reaction steps are involved, zinc hydroxide sol formation and dehydration from the sol. However, little is known about the underlying mechanism. In this study, molecular dynamics simulations were performed to investigate the structural and thermodynamic changes in the zinc acetate hydrolysis process, i.e., Zn(CH₃COO)₂, in supercritical water (SCW). Our results show that Zn(CH₃COO)₂ is prone to aggregate in SCW. On average, one Zn²⁺ ion coordinates with five CH₃COO^- species and one H₂O molecule, forming an octahedral configuration. WHowever, more water molecules bind Zn²⁺ at the SCW interface to form Zn(CH₃COO)₂ clusters. The total potential energy of each system decreases after the hydrolysis of Zn(CH₃COO)₂, suggesting that it is a thermally favorable process in SCW. The OH^- reaction product incorporates into the amorphous Zn(CH₃COO)₂ cluster and CH₃COOH is in the SCW phase. Our results provide a general theoretical framework for the Zn(CH₃COO)₂ hydrothermal synthesis in SCW.

Critical micelle concentration (CMC) is one of the most useful parameters for the characterization of surfactants; thus, CMC plays an important role in the investigation of the surfactants? properties for industrial applications and biological utilizations. The following study presents a stable and accurate structure-property relationship model for the prediction of CMC for a diverse set of 175 surfactants using a new topological index, the extended distance matrix. Research indicates that the new model based on this topological index is very efficient and provides satisfactory results. The high-quality prediction model is evidenced by an R² (square correlation coefficient) value of 0.9295 and an average relative difference (ARD) value of 8.20% for the training set, an R² value of 0.9257 and an ARD value of 6.76% for the testing set. Comparison results with reference models demonstrate that this new method based on the topological index results in significant improvements, both in accuracy and stability for predicting CMC of surfactants.

Istomin and Palm proposed a model, Δ_fH⁰(RX)=h[R]+h[X]+φ[R]φ[X], (the h[R] and h[X] are the contributions of alkyl R and substituent X to the Δ_fH⁰(RX), respectively. φ[R]φ[X] represents the interaction of alkyl R and substituent X), to express the enthalpies of formation of monoderivatives of hydrocarbons Δ_fH⁰(RX). However, in two-direction extending compounds R1-Y-R2, the Y substituent is attached to two alkyl groups (R1 and R2), and the intramolecular interactions are more complicated than that in monosubstituted alkanes. Thus, the Istomin-Palm model must be modified. In this work, the interactions among Y, R1, and R2 contributing to the enthalpy of formation, Δ_fH⁰(R1-Y-R2), are divided into three parts: the interaction between R1Y and R2(φ[R2]φ[R1Y]), the interaction between YR2 and R1 (φ[R1]φ[YR2]), and the interaction between R1 and R2 (ψ[R1]ψ[R2]). These three interactions replace the φ[R]φ[X] term, and a new extended Istomin-Palm model, Δ_fH⁰(R1-Y-R2)=h[R1]+h[R2]+h[Y] +φ[R1]φ[YR2]+φ[R2]φ[R1Y]+ψ[R1]ψ[R2], is proposed. In this model, h[Y] is the contribution of substituent Y to Δ_fH⁰(R1-Y-R2). The h[R1] and h[R2] terms are the contributions of alkyls R1 and R2 to Δ_fH⁰(R1-Y-R2). The last three terms are the total contribution of interactions among Y, R1, and R2. Furthermore, the interaction potential index IPI(X) reported in our recent work (Wu, Y. X.; Cao, C. Z.; Yuan, H. Chin. J. Chem. Phys. 2012, 25 (2), 153.) was employed to express the intrinsic interaction of Y with alkyl groups (φ[Y]), and two general expressions were established to estimate Δ_fH⁰, in which one is for thioethers, secondary amines, ethers, and ketones, and the other is for esters. These two estimating equations give results, which are as accurate as G3 and G3MP2 models in calculating Δ_fH⁰ for R1-Y-R2 compounds. Moreover, our method avoids time consuming calculations.

It is well known that the trans isomer of a doubly substituted ethylene is more stable than its cis counterpart because of the more favorable electrostatic and steric interactions in the trans conformer. Exceptions do exist nevertheless. 1,2-Difluoroethylene is such an example, so is 1,2-dichloroethylene. The unusual stability of the cis isomer of these doubly substituted ethylene compounds is referred to as the cis-effect, whose nature and origin are still not well understood. In this work, using 12 simple molecules, XHC=CHY (X, Y=F, Cl, Br, CN, CH₃, OCH₃, C₂H₆), as examples, we perform systematic studies to investigate the validity, nature, and origin of this effect. Among the systems studied, 9 of them exhibit the existence of the cis-effect and the remaining 3 systems are conventional systems used for the comparison purpose. We employ a large number of density functionals and basis sets to confirm its validity. We also use a few well-established analysis tools, such as natural bond orbital (NBO), energy decomposition analysis (EDA), density functional reactivity theory (DFRT), and non-covalent interaction (NCI) analysis, to pinpoint its nature and origin. We found that there exists a weak but attractive non-covalent interaction between the two substituting groups in the cis conformer. We also found that electrostatic, steric, and kinetic energies all play important roles for the validity of the cis-effect. Nevertheless, none of these quantities can be solely used as the single reason governing the general validity of the cis-effect, suggesting that the origin of the effect is complicated and its validity results from compound interactions from a number of interactions. In this work, we employ two-variable explanations to justify its validity through the electrostatic interaction plus steric effect or kinetic energy, with which reasonable fits with R²=0.86-0.87 were obtained.

Several 3-aminoquinazolin-4-(3H)-one derivatives were synthesized and characterized. Using proton nuclear magnetic resonance (NMR) spectra, we have investigated the barriers to rotation around the N-N bond as a function of temperature. Changes in the NMR spectra at high temperatures are explained in terms of hindered rotations of the N-N bond. Free energies of activation for the rate determining stereochemical process were calculated to be as high as 67-75 kJ·mol^-1. Ground state molecular geometries and vibrational frequencies were calculated using the HF/6-31G^** and B3LYP/6-31G^** level of theories. The optimized bond lengths and bond angles are in good agreement with experimental values at both theoretical levels.

A physically cross-linked gel polymer electrolyte (GPE) was obtained by photo-induced radical polymerization of a mixture of methoxy-poly(ethylene glycol) methacrylate (MPEGM), hexadecal-poly (ethylene glycol) methacrylate (HPEGM), triethylene glycol dimethyl ether (TEGDME), lithium salt (lithium perchlorate, LiClO₄) and photo-initiator (2, 2-Dimethoxy-2-phenylacetophenone, DMPA). The resulting polymers and gel polymer electrolytes were characterized by infrared spectroscopy (IR), differential scanning calorimetry (DSC), tensile test, and alternating current (AC) impedance measurements. The results showed that the physically cross-linked polymer matrix was formed by C₁₆ aggregation with the effect of electrostatic repulsion of PEO chains when the HPEGM content was high. The ionic conductivity of the obtained GPE is affected by its composition and the temperature. The GPE prepared with the optimum composition exhibited excellent mechanical properties and a relatively high ionic conductivity (up to 0.87×10^?3 S·cm^-1 at 30℃). In addition, the GPE was found to present a wide electrochemical window (from 0 V to 4.5 V vs. Li/Li⁺). In addition, a coin cell based on the gel electrolyte, with LiFePO₄/C as the cathode and metallic lithium as the anode, showed a discharge capacity as high as 154.7 mAh·g^-1 and 148.0 mAh·g^-1 at 30℃ under of 0.1 C and 0.2 C, respectively.

In this paper, the interface modification effects and electron processes in N3/Al₂O₃/N749 alternating structured dye-sensitized solar cells (DSCs) were studied. UV-Vis absorption and monochromatic incident photon-to-electron conversion efficiency (IPCE) spectra showed that the N3/Al₂O₃/ N749 structure broadened the photo-response range. Photocurrent-voltage (I-V) curves showed that enhanced conversion efficiencies were obtained. Compared with N3- and N749-only structures, the efficiency of the N3/Al₂O₃/N749 structure increased from 4.22% and 3.09% to 5.75% (36% and 86% enhancement), respectively. From electrochemical impedance spectroscopy (EIS) results, the N3/Al₂O₃/ N749 structure displayed increased interface resistance under dark conditions. This indicates that charge recombination is reduced in the N3/Al₂O₃/N749 device, which was confirmed from the dark current measurements. Furthermore, to analyze the electron processes, a series of equivalent circuit models were built to mimic the injection and recombination process in DSCs. Intensity modulated photocurrent spectroscopy (IMPS) and intensity modulated photovoltage spectroscopy (IMVS) also showed that this structure improved the electron life time and diffusion.

Mesoporous TiO₂ microspheres were synthesized using a simple template method. The effect of the alkyl chain length on the synthesis and properties of the TiO₂ microspheres was studied. A high power conversion efficiency (9.5%-10.1%) was attained by the dye-sensitized solar cells (DSCs) fabricated with the hierarchically mesoporous TiO₂ microsphere films. The physical properties of the TiO₂ microspheres were analyzed by X-ray diffraction (XRD), N₂ physisorption (BET), and scanning electron microscopy (SEM). The results indicated the TiO₂microsphere crystal structure to be in the pure anatase phase; the rough surface microstructure of the TiO₂ microspheres, formed through accumulation of nanocrystalline (14-18 nm diameter) TiO₂ particles, provides a proper large surface area and mesoporous structure. The hierarchically mesoporous TiO₂ microspheres can form good paths for mass transport, and also act as light scattering layers for efficient light harvesting. Meanwhile, the rough TiO₂ microsphere surface ensures a sufficient amount of dye uptake, and consequently improves the photo-generated electron density. Electrochemical impedance analysis demonstrated the advantage of using microspheres for mass transport in electrolytes.

In₂S₃ is a stable semiconductor material with low toxicity. We prepared In₂S₃ sensitized solar cells using low-cost chemical bath deposition methodology. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) were used to reveal the microstructure of the In₂S₃ sensitized TiO₂ nanoporous films. Our results indicated that the deposition temperature has a remarkable effect on the morphology of In₂S₃ sensitized TiO₂ films, which in turn affects the photovoltaic performance of devices. When the deposition temperature was low, the deposition reaction rate was slow, resulting in only minimal deposition. However, if the deposition temperature was increased too much, there was insufficient time for the In₂S₃ to be deposited within the internal pore structure of the TiO₂ mesoporous films. The best homogeneous In₂S₃ sensitized TiO₂ films were obtained with a deposition temperature of 40℃. At this temperature, the optical absorption of the resulting film was optimal and displayed the largest short circuit current density among the films examined. Moreover, the fill factor was also the best, approaching 65%. The best overall power conversion efficiency was 0.32%.

Co@Pt/C core-shell catalysts have been synthesized by a two-step chemical reduction method, followed by heat treatment in a H₂ and N₂ mixture. High resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS) techniques were used to characterize the catalyst microstructure and morphology. The results indicate that the core-shell structure of Co rich in core and Pt rich in shell is formed and the nano-particles are highly dispersed on the surface of the carbon support. Heat treatment affects the structure and morphology of the catalysts. The electrocatalytic performance, kinetic characteristics of O₂ reduction reaction (ORR), and durability of the catalysts were measured by cyclic voltammetry (CV) and linear sweep voltammetry (LSV) techniques. It was found that the formation of the core-shell structure is favorable for improving the performance and utilization of Pt. The Co@Pt/C catalyst mechanism proceeds by an approximately four-electron pathway in acid solution, through which molecular oxygen is directly reduced to water. Compared with alloy catalysts, the formation of the core-shell structure obviously improves the catalyst durability.

We demonstrate a direct carbonization method to prepare porous carbons as electrode materials without an activation process, using sodium carboxymethyl cellulose (NaCMC) as the carbon source, which are further doped with varying mass ratios of nitrogen. From X-ray photoelectron data, the nitrogen species include pyridinic N, graphitic N, and pyrrolic N. The relative mass ratios of NaCMC and CO(NH₂)₂ affect the nature of the nitrogen species, dopant dosages as well as specific surface areas and pore structures. The cyclic voltammetry and galvanostatic charge-discharge measurements in 6 mol·L^-1 KOH aqueous solutions reveal that the specific surface areas and capacitive performances improve after nitrogen-doping. Taking carbon-N-1:20 as example, its S_BET can reach 858 m²·g^-1, which is higher than that of carbon-blank (463 m²·g^-1) and the corresponding specific capacitance greatly improves from 94.0 to 156.7 F· g^-1, respectively. The present carbons are excellent electrode candidates for high-rate electrochemical capacitors.

Nitrogen-doped carbon nanotubes (NCNTs) were prepared by carbonization of polyanilinecoated CNTs that were synthesized by in-situ polymerization of aniline on the CNT surface. The laser Raman spectroscopy, transmission electron microscope (TEM), and X-ray photoelectron spectroscopy (XPS) indicated that carbonization treatment of the polyaniline (PANI) coated CNTs produced NCNTs owning the core-shell structure of a nitrogen-doped carbon shell and a CNT core, without destroying the intrinsic CNT structure. By increasing the aniline amount, the N-doped layer of the NCNTs became thicker, and the amount of nitrogen doping increased from 7.06% to 8.64% (mass fraction). As the supercapacitor electrode material, the NCNTs capacitance in 6 mol·L^-1 aqueous KOH solution increased from 107 to 205 F·g^-1 as the N-doped layer thickness decreased, which was much higher than the capacitance of 10 F·g^-1 for the pristine CNTs. Especially, NCNT electrodes displayed good cyclability, maintaining 92.8%-97.1% of the initial capacitance after 1000 charge-discharge cycles. The high capacitance and good cyclability of the NCNTs as a supercapacitor electrode material can be attributed to the pseudo-Faradic capacitance and improved hydrophility contributed by the nitrogen functional groups and the core-shell structure of the NCNTs, respectively.

Graphene/polyaniline composites (GP) were prepared from aniline and graphite oxide using an electrochemical method. The structure characterization and surface morphology were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS), and its electrochemical properties were measured. The results show that the composite keeps the basic morphology of graphene and that the polyaniline particles are uniformly dispersed. The specific capacitances of the composite materials reach 352 and 315 F·g^-1 at 500 and 1000 mA·g^-1, respectively, higher than those of graphene and polyaniline. The majority (90%) of the capacitance remains after 1000 cycles of charge and recharge at 1000 mA·g^-1. The composite shows potential for use in supercapacitors.

The composite Ni-P/(LaNi₅+Al) coating was plated by the composite electro-deposition. Then, the porous composite Ni-P/LaNi₅ coating was successfully prepared by dissolution Al with the concentrated alkali solution. The composition and structure of the coating were characterized by scanning electron microscopy (SEM) and energy dispersive X-ray (EDS), and X-ray diffraction (XRD). In 20% (w) NaOH solution, the electro-catalytic and stable properties for hydrogen evolution reaction (HER) of the porous composite Ni-P/LaNi₅ electrode were evaluated by electrochemical linear voltammetric scanning (LSV), constant potential electrolysis, and electrochemical impedance spectroscopy (EIS). As a result, the porous composite electrode exhibits a lower over-potential for HER, a higher specific surface area, and a better stabilization than that of the porous Ni-P electrode. The apparent activation energy for HER on the porous composite Ni-P/LaNi₅ electrodes is 35.44 kJ·mol^-1, which is lower than that of the porous Ni-P (50.91 kJ· mol^-1).

3,4-Didodecyloxybenzylamine (DDOBA), a novel surfactant with two alkyl tail chains, was designed and synthesized. DDOBA-capped hydrophobic gold nanoparticles were successfully fabricated using formic acid as a reducing agent in a DDOBA/n-butanol/n-heptane/formic acid/HAuCl₄·4H₂O water/oil (W/O) microemulsion system under microwave irradiation. DDOBA-stabilized gold nanoparticles were characterized by ultraviolet-visible (UV-Vis) spectroscopy, transmission electron microscopy (TEM), high resolution transmission electron microscopy (HR-TEM), and X-ray diffraction (XRD). The experimental results showed that DDOBA not only participated in the formation of a stable W/O microemulsion system, but also became a good protecting agent for gold nanoparticles. Within an appropriate concentration range of components in the W/O microemulsion system, hydrophobic gold nanoparticles with high monodispersity can be obtained using this experimental method and automatically form large areas of ordered monolayer built with DDOBA-capped gold nanoparticles at the air/water interface.

Zeolite membranes with their advantageous separation and catalytic properties can be coated on traditional catalysts to achieve highly effective perfermance. It is difficult to coat zeolite membranes onto activated carbon (AC) particles, a commonly used catalyst support, because of the hydrophobic and rough surfaces of AC. To overcome these shortcomings, a boehmite gel modified seeded method was developed to synthesize MFI-type zeolite membrane encapsulated AC particles. By using the spray-coating process, the boehmite sol precursor was introduced in a gel layer on the AC surface to provide a smooth surface for seed dispersion and a binder for seed fixation. The obtained seed layer was dense and firm even without calcination. After 6 h rotary hydrothermal synthesis, continuous zeolite membrane encapsulated AC particles were obtained. The synthetic membrane type and the composite material morphologies were elucidated by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The results indicate that MFI-type zeolite membrane has a thickness of 5 μm. For comparison, on AC particles without boehmite gel modification, no continuous membrane forms. Our boehmite gel modified seeded strategy provides an efficient way to prepare zeolite membranes on different inert supports.

The effect of functionalization of activated carbon with ethylenediamine tetraacetic acid (EDTA) on surface functional groups, the structure of carbon-supported Pd nanoparticles, and the electrocatalytic performance of Pd catalysts were investigated. Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) indicate that N-containing groups are introduced to the carbon surface via EDTA treatment. X-ray powder diffraction (XRD) spectra, transmission electron microscopy (TEM), and electrochemical measurements demonstrate that the electrocatalytic activity and stability for carbon-supported Pd catalysts were substantially enhanced when the carbon support was treated with EDTA, although the Pd particles size increased slightly. The improved electrocatalytic performance may be due to enhanced interactions between the Pd particles and the carbon support, resulting in an improved Pd utilization. Electrochemical impedance spectrum analysis further reveals that the Pd catalyst on EDTA-treated carbon (Pd/C-E) displayed a lower charge-transfer resistance for the electro-oxidation reaction of formic acid.

A series of Co-doped ZnIn₂S₄ photocatalysts were prepared via a solvothermal synthesis method. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and UV-visible (UV-Vis) diffuse reflectance spectroscopy. The results indicated that the Co was successfully incorporated into the ZnIn₂S₄ lattice as confirmed by XRD and XPS. With increasing Co concentration, the absorption edge of the samples shifted to longer wavelength, while the morphology of ZnIn₂S₄ was gradually destroyed. Photocatalytic results demonstrated that Co²⁺ doping could greatly enhance the photocatalytic activity of ZnIn₂S₄. The optimal amount of Co doping for the ZnIn2S4 photocatalyst was 0.3%(w), which displayed the highest photocatalytic activity. The possible photocatalytic mechanism was discussed.

Polyacrylic acid grafted polytetrafluoroethylene (PAA-g-PTFE) fibers were coordinated with Fe³⁺ ions and with a mixture of Cu²⁺ and Fe³⁺ ions to prepare PAA-g-PTFE Fe and Cu-Fe bimetallic complexes. The chemical structures and light adsorption properties of the complexes were characterized using Fourier transform infrared (FTIR) spectrometry and UV-Vis diffuse reflection spectroscopy (DRS), respectively. The complexes were used as heterogeneous photo-Fenton catalysts in the oxidative degradation of the azo dye, Reactive Blue 222, in different pH aqueous media. The results indicate that Fe³⁺ coordinates with six carboxyl groups grafted on the surface of PAA-g-PTFE in the presence or absence of Cu²⁺ ion, and improved light adsorption properties are achieved in the UV and visible regions. When both metal ions coexist in solution, the Cu²⁺ ion coordinates more easily with PAA-g-PTFE than Fe³⁺ to produce a PAA-g-PTFE Cu-Fe bimetallic complex. Moreover, PAA-g-PTFE Fe significantly increases the degradation of Reactive Blue 222 in the pH range 3-9 under visible irradiation. However, at high pH conditions (> 7) the catalytic ability is reduced. Increasing the Fe content, and especially incorporating Cu²⁺ ions in the complex, dramatically improves the catalytic reusability at high pH value.

Core-shell photocatalysts of hierarchical porous nanospheres (HP-Fe₂O₃@TiO₂) have been designed and prepared using solvothermal and sol-gel methods. Transmission electron microscopy (TEM) images confirm that the obtained samples a hierarchical porous structure, which results from both the macroporous structure of the core (Fe₂O₃) and the mesoporous structure of the shell (TiO₂). X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption-desorption isotherms were employed to characterize the structure and properties of HP-Fe₂O₃@TiO₂ nanospheres. We investigated the photocatalytic degradation (in the presence of H₂O₂) of methylene blue (MB) irradiated under visible and ultraviolet light. The observed photocatalytic performance of HP-Fe₂O₃@TiO₂ nanospheres is attributed to the synergetic effects of the core-shell structure, which indicates that the TiO₂ shell enhances the photocatalytic performance of α-Fe₂O₃. HP-Fe₂O₃@TiO₂ (1 mL Ti(OC₄H₉)₄ (TBT)) possesses the highest photodegradation reaction constant among all samples under visible light irradiation. Moreover, HP-Fe₂O₃@TiO₂ (4 mL TBT) has an optimal monodisperse morphology and achieves high photocatalytic activity under ultraviolet light irradiation.

A series of MnO_x/Al-SBA-15 catalysts were prepared by post synthesis methods for lowtemperature selective catalytic reduction (SCR) of NO_x with NH₃. Structural properties and catalytic performance were comprehensively characterized by Fourier transform infrared (FTIR) spectroscopy, N₂ adsorption-desorption, X-ray powder diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and temperature programmed desorption of NH₃ (NH₃-TPD). The results showed that moderate addition of Al improved the SCR activity of the MnO_x/SBA-15 catalyst, and the MnO_x/Al-SBA-15 catalyst with n_Si/n_Al=50 had the highest activity. Characterization results revealed that the doped material MnO_x/Al-SBA-15 catalysts maintained high specific surface area, large pore volume, and uniform pore size. Al doping improved the concentration and valence state of Mn, where MnO₂ was determined to be the main active phase. Owing to a high dispersion of MnO_x and a stronger surface acidity, the MnO_x/Al(50)-SBA-15 catalyst exhibited higher SCR activity.

A small-crystal titanium silicalite-1 (TS-1) with a size of 600 nm×400 nm×250 nm was synthesized using a nano-sized TS-1 mother liquor as the seed in a tetrapropyl ammonium bromide (TPABr)-ethylamine hydrothermal system, and was extruded with silica sol. The obtained TS-1 extrudate was characterized by X-ray powder diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, ultraviolet-visible (UV-Vis) diffuse reflectance spectroscopy, and nitrogen physisorption. The reaction conditions, including temperature, pressure, molar ratio of propylene/H₂O₂ (n(C₃H₆)/n(H₂O₂)), the weight hourly space velocity (WHSV) of propylene, methanol and H₂O₂, and the concentration of NH₃·H₂O, were systematically studied to identify ideal condition propylene epoxidation over small-crystal TS-1 extrudate. The reaction temperature had little effect on the propylene oxide (PO) yield under the conditions examined. The highest PO yield was obtained when the pressure was 2.0 MPa and the n(C₃H₆)/n(H₂O₂) was 4. The PO content in the product was maximized when the WHSVs of propylene, methanol and H₂O₂ was 0.93, 2.5 and 0.25 h^-1respectively. A low concentration of NH₃·H₂O was beneficial for a high PO yield. Under the optimized condition, we compared catalytic performances of TS-1 with different crystal sizes and performed a long-term test over the small-crystal TS-1. The tests indicated that H₂O₂ conversion and PO selectivity could both reach 95%, even after 1000 h on stream.

An immobilized cationic phenyl porphyrin was prepared with crosslinked polystyrene (CPS) microspheres as carriers via synthesis and immobilization. A kind of immobilized cationic cobalt porphyrin was obtained through a coordination reaction between the immobilized cationic phenyl porphyrin and the cobalt salt. In the composite reactions, phosphotungstic acid (HPW) and phosphomolybdic acid (HPMo) with Keggin structures were used as reagents, respectively, and the combination of the cationic cobalt porphyrin (CoP) with the heteropoly anions by electrostatic interaction led to the formation of the immobilized composite catalysts of CoPPW-CPS and CoPPMo-CPS. We then characterized these immobilized composite catalysts. The immobilized composite catalysts were used in the oxidation of ethylbenzene by molecular oxygen, and their catalytic characters were investigated. The results show that the immobilized composite catalysts possess high catalyst activity. They can transform ethyl benzene into acetophenone with high selectivity, and the yield of acetophenone after 12 h reaches 30.1%. The catalytic activity of the immobilized composite catalysts is 75% higher than that of the immobilized cobalt porphyrin. The catalytic activity of CoPPW-CPS is higher than that of CoPPMo-CPS. The cobalt porphyrin in the composite is the catalyst component as the heteropoly has no catalytic activity. However, the heteropoly anion has a protective effect on the metalloporphyrin against its deactivation during the catalytic reaction. In the oxidation reaction, there is an optimum addition for catalyst, and adding excessive catalyst inhibits its activity. The composite catalysts show good recycle properties.

Lipid peroxidation (LPO) plays an important role in many pathological processes (such as hepatitis, hepatic sclerosis, atherosclerosis, cerebral hemorrhage and so on), and flavonoids are considered to be effective LPO-inhibitors. Thus we investigated the relationship between the chemical structure of flavonoids and the LPO activity and the antioxidant mechanism of flavonoids. In this work, α-hydroxyl ethyl peroxyl radicals were produced from radiolysis of aerated ethanol to model lipid peroxyl radicals. By detecting the decay of α-hydroxyl ethyl peroxyl radicals in the presence of different concentrations of flavonoids using pulse radiolysis, the reaction rate constants of α-hydroxyl ethyl peroxyl radicals with quercetin, rutin, catechin, and baicalin are determined for the first time. The antioxidant activity of these flavonoids decreases in the order: rutin > quercetin > baicalin > catechin. Flavone and pyrocatechol were used as model compounds for the different components in flavonoids and their reaction rate constants towards α-hydroxyl ethyl peroxyl radicals were (1.7±0.1)×10⁶ and (2.9±0.1)×10⁵ mol^-1·dm³· s^-1, respectively. The effect of chemical structure on the scavenging activity towards α-hydroxyl ethyl peroxyl radicals was investigated. The coexistence of the C₅-hydroxyl group in the A ring with the C₂＝C₃ in the C ring or the conjugated double bond of the B-C ring and the catechol group in the B ring provides the best antioxidant activity. In addition, the C₂＝C₃ in the C ring or the conjugated double bond of the B-C ring is more effective than the catechol group in the B ring, while the C₃-rutinose in the C ring has no obvious effect. Therefore, we conclude that the addition reaction between double bonds with peroxyl radicals plays an important role in the antioxidant activity of flavonoids in LPO.

High-energy electrons play the most important role in the decomposition of ethanol aqueous solutions under glow discharge plasma electrolysis (GDE). The non-Faradaic currents greatly improve, resulting in the actual gas production yield exceeding the theoretical yield. In this paper, we investigated a novel process of hydrogen generation from ethanol decomposition by GDE. The main gaseous products were H₂ and CO; in addition to small amounts of C₂H₄, CH₄, O₂, and C₂H₆. The H₂ volume fraction was above 59% and CO was 20%. We conclude that voltages of points C and D (V_C and V_D) do not change with the electrolyte concentration, but the 'Kellogg area' becomes narrower with increasing electrolyte conductivity and the glow discharge is easier to attain. In addition, with increasing ethanol volume fraction, the H₂ volume fraction decreases. The maximum gas production rate occurred for ethanol volume fractions of 30% and 80%. Improving the discharge voltage and raising the electrolyte conductivity had the same effect on glow discharge plasma electrolysis as the voltage load at both ends of the plasma steam sheath increases. The H₂ volume fraction remains the same upon varying the discharge voltage or electrolyte conductivity, but increasing the electrolyte conductivity is advantageous to reduce Joule heating effects caused by GDE.

Stable and transient spectroscopic studies were conducted to investigate the influence of DNA phosphate bases in the process of DNA damage photo-induced by ciprofloxacin (CPX). The results of UV-visible and fluorescence studies confirmed that the absorption and emission properties of CPX were affected by the concentration of phosphate buffer (PB), and these results indicated that there are interactions between CPX and the phosphate anion. To investigate the relationship between the phosphate base and CPX, a comparative experiment was conducted using guanosine (Gua), 2'-deoxyguanosine (dG), and 2'-deoxyguanosine-5'c-monophosphate (dGMP). By comparative experiments, we found that the type of spectrum of CPX triplet state was changed due to the phosphate base of dGMP, hence, we concluded that the photo-damage process was changed. The effects of phosphate base of dGMP on the CPX triplet state (³CPX^*) spectrum have been investigated by laser flash photolysis methods, and the results confirmed that there are hydrogen-bonding interactions between the phosphate base of dGMP and CPX. In this study, we found that CPX and dGMP are combined together by the hydrogen bond which changed the mode of DNA damage photo-induced by CPX. Finally, based on the results obtained in this study, a rational scheme to describe the role of phosphate base playing in the DNA damage process photo-induced by CPX is proposed.

Influenza is a major respiratory infection associated with significant morbidity in the general population and mortality in elderly and high-risk patients. Research has shown that inhibiting neuraminidase (NA) prevents RNA replication, so NA is an important drug target in the treatment of H1N1 influenza virus. It is becoming increasingly important to screen and predict molecules that have NA inhibitory activity by computational methods. In this work, we explored several machine learning methods (support vector machine (SVM), k-nearest neighbor (k-NN), and C4.5 decision tree (C4.5 DT)) for predicting NA inhibitors (NAIs). These predictive systems were tested using 227 compounds (72 NAIs and 155 non-NAIs), which were significantly more diverse in chemical structure than those used in other studies. A feature selection method was used to improve the accuracy of the predictions and the selection of molecular descriptors responsible for distinguishing between NAIs and non-NAIs. The prediction accuracies were 75.9%-92.6% for all the compounds, 64.3%-78.6% for NAIs, and 77.5%-97.5% for non-NAIs. The SVM method gave the best total accuracy of 92.6% for all of methods. This work suggests that machine learning methods can be useful to predict potential NAIs from unknown sets of compounds and to determine molecular descriptors associated with NAIs.

一年来(2011 年11 月15 日-2012 年11 月20 日), 有1047 位老师(名单按姓名拼音字母排序)非常认真细致、无偿而且及时(初审平均19 天、复审平均8 天)地完成了审稿, 提出了很多客观、中肯的意见和建议. 他们的辛勤劳动和无私奉献使得《物理化学学报》能够高质量、快速(网络版平均出版周期为72 天, 印刷版为150 天)地发表作者的优秀研究成果, 促进了学术交流. 谨向他们致以衷心的谢忱和崇高的敬意!

A chemical kinetic model containing 46 species and 167 reactions was developed for the auto-ignition and combustion of n-decane. On the basis of a significant reduction of the mechanism proposed by Peters (118 species and 527 reactions)—where the reduction was achieved using reaction path analysis and a sensitivity analysis—the newly developed mechanism was obtained by correcting and improving some elementary reactions important for auto-ignition at lower temperatures and laminar flame speeds. When compared with experimental results, not only did the mechanism contain fewer species and reactions than other models, it could also predict the auto-ignition delay time at lower and higher temperatures and laminar flame speeds more precisely. The development of this model represents a significant step toward a global model that could be coupled with computational fluid dynamics.

Solidification processes of liquid Fe with embedded homogeneous solid nanoparticle whose radius ranges from 0.4 to 1.8 nm have been studied by molecular dynamics simulation adopting the Sutton-Chen potential. It was found that the particles whose radii exceed 0.82 nm can obviously decrease the critical undercooling (ΔT^*) and induce solidification. The microstructural evolution during the solidification process is traced through the atom definition with cluster-type index method (CTIM-2). Results revealed that when the embedded particle induced solidification, the growth process of nucleus would proceed as a cross-nucleation between hcp and fcc structures, a little similar to the eutectic crystallization process. Moreover, the heredity effect attributed by embedded solid nanoparticle is clearly observed during the microstructural evolution.

First-principles calculations were applied to design and study the electron transport behavior of a biomolecular sensor with graphene-based electrodes. It is shown that the designed biosensor is capable of distinguishing different nucleotide molecules such as cytosine, methylcytosine, and hydroxymethylcytosine. The current was seen to change by nearly one order of magnitude, while molecules passed through the device individually. The resolution capacity of the present device was primarily determined by the interactions and specific configurations of two adjacent single-stranded desoxyribonucleic acid (DNA) molecules and their specific configurations. This graphene-based biosensor was proved to be effective and efficient in detecting and distinguishing different DNA molecules, which provides a new potential method to pinpoint exactly varietal base molecules in DNAchains for the genetic information.

Taking dye D5 molecules as the prototype, different types and different elemental quantities of conjugate π bridge was used to design D-π-A organic molecules. Density functional theory (DFT) and timedependent density functional theory (TDDFT) were adopted to simulate the geometric structures, molecular orbital energy levels, and UV-Vis absorption spectra of the molecules, with the aim of finding conjugate π bridge in the sensitizer molecules for dye-sensitized solar cells (DSSCs). The absorption spectra of the molecules using “methenyl chains”,“furan rings” or “thiophene rings”,“methenyl chains and furan rings”, or “methenyl chains and thiophene rings” as conjugate π bridge showed a gradually increasing red-shifting trend. With increases in the number of conjugate π bridge elements, the absorption spectrum showed an intense red-shift, which weakened gradually; under the same conditions, the lowest unoccupied molecular orbital (LUMO) energy level of the molecules gradually decreased, and the highest occupied molecular orbital (HOMO) energy level gradually increased. The HOMO energy levels of the molecules with three“methenyl chain and furan ring”or“methenyl chain and thiophene ring”elements as conjugate π bridge were higher than the energy level of the redox electrolyte; in polar solutions, the HOMO energy levels of the molecules adopting two “methenyl chain and furan ring” or “methenyl chain and thiophene ring” elements as conjugate π bridge were higher than the energy level of the redox electrolyte. The absorption spectra of the organic sensitizer molecules with several “methenyl chain and furan ring” or “methenyl chain and thiophene ring” elements as conjugate π bridge showed an intense red-shift. These results showed that for DSSCs sensitizer molecules, it is not necessary to have many conjugate π bridge elements; one to two elements is typically enough.

The interaction of methanethiol (CH₃SH) molecules with the Cu(111) surface was investigated using a first-principles method based on density functional theory, and a slab model. A series of possible adsorption configurations constructed using S atoms on different sites with different tilt angles were studied. It was found for the first time that the non-dissociative molecular adsorption of CH₃SH on the Cu(111) surface with the S atom sitting on the top site belongs to the weak chemisorption, and the adsorption energy is 0.39 eV. After the dissociation of the S―H bond, the S atom is located at the bridge site, with a small shift toward the hollow site. The dissociative adsorption structure is thermodynamically more stable than the intact one, and the adsorption energy is 0.75-0.77 eV. Two reaction pathways have been studied for the transition from non-dissociative adsorption to dissociative adsorption, and the activation energy barrier along the minimum energy path is 0.57 eV. The results of the calculations indicated that the released H atom prefers to form a bond with the copper surface, rather than desorbing in the H₂ molecular form. Comparing the local density of states of S atoms in the single CH₃SH, CH₃SH/Cu(111), and CH₃S/Cu(111) structures, we found that the bonding between the S atoms and the substrate is much stronger in the dissociated adsorption states.

Using density functional theory, the adsorption behaviors of HF at α-AlF₃(0001) surfaces with different coverages of 3F, 2F, 1F, and Al terminations were studied systematically. The electronic interactions between HF and the α-AlF₃(0001) surfaces were also analyzed. Our results indicated that physisorption occurs when HF adsorbs at the 3F-terminated surface. Strong chemisorption occurs, and Al-F and FHF structures form when HF adsorbs at surfaces with 2F and 1F terminations. Under these conditions, the HF molecule is activated, and might take part in the subsequent fluorination reactions. Dissociated adsorption occurs, and Al-F and Al-H bonds form when HF is adsorbed on the Al-terminated surface. The unsaturated coordination numbers for surface Al with 3F, 2F, 1F, and Al-terminated surfaces are 0, 1, 2, and 3, respectively. The coordination number of the AlF2 surface is saturated when one HF molecule adsorbs; then, only physical adsorption occurs for any subsequently adsorbed HF molecules. However, it can still chemisorb at the 1F and Al-terminated surfaces. It is therefore reasonable to deduce that the higher the unsaturated coordination number of the surface, the higher the amount of activated HF, and possibly the higher the catalytic activities in the fluorination reactions. Charge density difference and density of states indicated that weak interactions occur between the HF and the 3F-terminated surface, while strong interactions occur between the HF and the 2F, 1F, Al-terminated surfaces.

The reaction mechanisms of ethylene hydrogenation catalyzed by Au(I) complexes AuX (X=F, Cl, Br, I) and AuPR₃⁺ (R = F, Cl, Br, I, H, Me, Ph) were investigated using density functional theory at the B3LYP level. The calculated results indicated that Au(I) complexes were effective catalysts in the hydrogenation of ethylene. AuPR₃⁺ showed higher catalytic activity than AuX and the effect of changing the electron donating or withdrawing ability of the ligand on catalytic activity was large. Natural bond orbital analysis indicated that the interactions between the Au(I) complex and H₂/C₂H₄ not only weakened the H― H/C＝C bond strength, but also decreased the energy of the σ_H―H^*、π_C＝C^* orbital level. As a result, the energy differences of π_C＝C-σ_H―H^*/σ_H―H-π_C＝C^* decreased, and ethylene hydrogenation was facilitated. A linear correlation was observed between the activation energies and π_C＝C-σ_H―H^*/σ_H―H-π_C＝C^*. The more an Au(I) complex affected the σ_H―H^*/π_C＝C^* orbital levels, the higher its catalytic activity.