Copper‐Bismuth Bimetallic Microspheres for Selective Electrocatalytic Reduction of CO2 to Formate

Electrocatalytic carbon dioxide reduction holds great promise for reducing the atmospheric CO₂ level and alleviating the energy crisis. High‐performance electrocatalysts are often required in order to lower the high overpotential and expedite the sluggish reaction kinetics of CO₂ electroreduction. Copper is a promising candidate metal. However, it usually suffers from the issues of poor stability and low product selectivity. In this work, bimetallic Cu‐Bi is obtained by reducing the microspherical copper bismuthate (CuBi₂O₄) for selectively catalyzing the CO₂ reduction to formate (HCOO^–). The bimetallic Cu‐Bi electrocatalyst exhibits high activity and selectivity with the Faradic efficiency over 90% in a wide potential window. A maximum Faradaic efficiency of ~95% is obtained at –0.93 V versus reversible hydrogen electrode. Furthermore, the catalyst shows high stability over 6 h with Faradaic efficiency of ~95%. This study provides an important clue in designing new functional materials for CO₂ electroreduction with high activity and selectivity.     

新型含二茂铁有机配合物的合成及其电化学性质

以二茂铁为起始原料,经氯汞化反应、溴代反应、Suzuki偶联反应、水解反应和取代反应等5步反应合成了一种新型的含二茂铁结构单元的有机配合物(7),其结构经1H NMR、13C NMR、IR和HR-MS(ESI-TOF)表征。电化学研究结果表明:化合物6的E1/2小于化合物7,具有较高的氧化还原活性。     

锂离子电池锡氧化物基负极材料的湿化学合成与电化学性质

采用新兴的湿化学方法合成了锡氧化物基粉末材料。用X-射线衍射、扫描电镜和电化学方法对材料的微观结构、形貌和电化学性能进行了详细的研究。结果表明，经400 ℃热处理4 h的锡氧化物基材料的颗粒大小均匀，平均粒径约为200 nm。这种材料的可逆充电容量超过570 mAh·g^-1，30次循环后平均每次循环的容量衰减只有0.15%。良好的电化学性能表明锡氧化物基材料有望作为新一代锂离子电池的负极材料。     

磺胺甲恶唑在二硫化钼纳米片修饰电极上的电化学行为

采用了研磨后超声和离心分离方法制备了二硫化钼纳米片,通过原子力显微镜(AFM)和扫描电子显微镜(SEM)对不同离心速度分离的二硫化钼纳米片进行了表征。使用循环伏安法(CV)和差分脉冲伏安法(DPV)在磺胺甲恶唑溶液中对二硫化钼纳米片修饰的玻碳电极进行了电化学行为研究。结果显示,磺胺甲恶唑在二硫化钼修饰电极的循环伏安图上有一对氧化还原峰。其峰电流值与扫描速度的平方根成正比,是扩散控制过程。DPV扫描结果显示,磺胺甲恶唑的峰电流与其浓度之间存在着明显的线性关系。研磨超声方法制备出的二硫化钼纳米片层材料在电极上能够加速电子的转移和传输,从而有效提高峰电流值,为进一步研制准确测定磺胺甲恶唑电化学传感器提供了一种可选择的材料和电化学分析方法。     

类球形正交LiMnO2的制备、微结构和电化学性能

以共沉淀法得到的类球形MnCO₃为前驱物，制备了类球形正交LiMnO₂(So-LiMnO₂)，采用XRD、SEM和N₂吸附技术对样品进行表征；与非球形正交LiMnO₂(No-LiMnO₂)进行了对比研究。结果表明：o-LiMnO₂的堆垛层错度、结晶状况、颗粒形貌和大小与前驱物的微结构密切相关；在80次电化学循环测试过程中，So-LiMnO₂经15次循环可达最大的放电容量152 mAh·g^-1，其容量衰减平均每次循环0.58 mAh·g^-1；而No-LiMnO₂要经过38次循环才能达到最大放电容量128 mAh·g^-1，容量衰减平均每次循环高达1.24 mAh·g^-1。TEM和EDS分析证明：由一次粒子团聚的类球形So-LiMnO₂能有效地抑制电解液对材料的腐蚀、减少Mn的溶解，从而提高了电化学循环能力。     

A Procedure for Transforming Impedance Spectra for the Determination of Mechanism of Electrochemical Reactions

Transformation of impedance spectra into relaxation time spectra (RTS) is used for determining contributions of individual processes of the oxygen electroreduction reaction (OER) to the polarization resistance of the electrochemical cell. The transformation technique involves the solution of the convolution equation found with the aid of a modified Van Cittert iteration algorithm checked on model impedance spectra. The technique, when used to analyze impedance spectra of electrochemical cells air|Pt|YSZ|YSZ + Pt|air, shows that the conversion of a globular structure of the YSZ + Pt cermet layer to a columnar one is accompanied by a change of peak amplitudes in RTS. The revealed RTS dynamics when heated to 750°C is compared with peculiarities of individual processes in OER.     

配合物[Cu2(phen)2](SiW12O40)(H2O)7的合成、晶体结构及电化学分析

The title complex has been synthesized by the reaction of silicotungstic acid, 1,10-phenanthroline (phen) monohydrate and cupric acetate. The crystal structure belongs to triclinic system, space group P1 with a=1.158 46(15) nm, b=1.658 8(2) nm, c=1.664 4(2) nm, α=82.090(2)°, β=76.001(2)°, γ=86.531(2)°, and V=3.072 6(7) nm³, D_c=3.887 g·cm^-3, Z=2, F(000)=3 196. R₁=0.086 7, wR₂=0.185 8. The structure shows that the copper(Ⅱ) atom is coordinated with two nitrogen atoms from the one phen and three oxgygen atoms from three water, forming a distorted square-pyramid configuration The cyclic voltametric behavior of the complex is also reported. CCDC: 298807.     

咪唑-金属配合物的合成、性质及其与DNA的作用机理

Three hexakis（imidazole）metallo complexes of Co, Cd and Ni were synthesized and spectroscopically characterized. The crystal and molecular structures have been determined by X-ray crystallography analysis. The metal ions have an octahedral geometry with the MN6 chromophore. The electrochemical experimental results indicate that both [Co（Im）6]C12·2HCl·2H2O （1） and [Ni（Im）6]C12·4H2O （3） [Im=imidazole] could interact with DNA mainly by intercalation.     

Conducting graft copolymers of poly(3‐methylthienyl methacrylate) with pyrrole and thiophene

A thiophene‐functionalized methacrylate monomer (3‐methylthienyl methacrylate) was synthesized via the esterification of 3‐thiophene methanol with methacryloyl chloride. The methacrylate monomer was polymerized by free‐radical polymerization in the presence of azobisisobutyronitrile as the initiator. Graft copolymers of poly(3‐methylthienyl methacrylate) (PMTM2) and polypyrrole and of PMTM2 and polythiophene were synthesized by constant‐potential electrolyses. p‐Toluene sulfonic acid, sodium dodecyl sulfate, and tetrabutylammonium tetrafluoroborate were used as the supporting electrolytes. PMTM2‐coated platinum electrodes were used as anodes in the polymerization of pyrrole and thiophene. Moreover, the oxidative polymerization of poly(3‐methylthienyl methacrylate) (PMTM1) was studied with FeCl₃ as the oxidant. The self‐polymerization of PMTM1 was also investigated by galvanostatic electrolysis both in dichloromethane and in propylene carbonate. The structures of PMTM1 and PMTM2 were investigated by several spectroscopic and thermal methods. The grafting process was elucidated with conductivity measurements, Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and scanning electron microscopy studies. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4131–4140, 2002     

Simons electrochemical fluorination of substituted homopiperazines(hexahydro-1,4-diazepines) and piperazines

Simons electrochemical fluorination (ECF) of 1,4-dimethyl-1,4-homopiperazine, methyl 4-ethylhomopiperazin-1-ylacetate and 1,4-bis(methoxycarbonylmethyl)-1,4-homopiperazine was studied. For comparison, ECF of three piperazines with a N-(methoxycarbonylmethyl) group(s) was also studied. ECF of 1,4-dimethyl-1,4-homopiperazine gave a low yield of corresponding perfluoro(1,4-dimethyl-1,4-homopiperazine) together with perfluoro(2,6-diaza-2,6-dimethylheptane) as the major product. Corresponding perfluoro(homopiperazines) with mono- and/or di-(fluorocarbonyldifluoromethyl) groups [CF₂C(O)F] at the 1- and/or 4-position were formed in low yields from methyl 4-ethylhomopiperazin-1-ylacetate and 1,4-bis(methoxycarbonylmethyl)-1,4-homopiperazine, respectively. These new seven-membered perfluoro(1,4-dialkyl-1,4-homopiperazines) were accompanied by the formation of mono- and/or di-basic linear perfluoroacid fluorides resulting from the CC bond scission at the 2- and 3-positions of the ring. From mono- and/or di-N-(methoxycarbonylmethyl)-substituted piperazines, corresponding perfluoropeperazines having the acid fluoride group(s) were formed in low yields.