Au和Ag电极上CO_2电还原反应的动力学特征对比

Comparison of Kinetic Characteristics of Electrochemical Reduction of CO_2 on Au and Ag Electrodes

采用循环伏安和塔菲尔曲线、恒电位电解、气相色谱方法,研究了CO2在Au,Ag电极上发生电还原反应的动力学特征.结果表明,在0.1 mol/L KHCO3水溶液中,CO2可在Au,Ag电极上发生电还原反应生成CO,CO2在Au和Ag电极上被电还原为CO的平衡电位分别为-0.720和-0.934 V,交换电流密度为0.4014和0.3011 m A/cm2,传递系数为0.33和0.35,电荷转移电阻为31.98和42.64Ω?cm2,最高电流效率为82%和65%.表明Au电极的催化活性高于Ag电极.

The electrochemical kinetic characteristics of CO2 reduction are studied in 0.1 mol/L KHCO3 aqueous solution using cyclic voltammetry,Tafel curve,potentiostatic electrolysis and gas chromatogram.The results show that CO2 can be reduced to CO on Au and Ag electrodes.The equilibrium potential,exchange current density,transfer parameter and charge transfer resistance on Au and Ag electrodes obtained are-0.720 and-0.934 V,0.401 4 and 0.3011 m A/cm^2,0.33 and 0.35,and 31.98 and 42.64 Ω·cm^2,respectively,their Faradaic efficiencies reach 82% and 65%,respectively.Au electrode exhibits higher activity than Ag electrode.