乙醇在Ni-Mo合金电极上氧化的动力学模型

利用循环伏安以及稳态极化曲线等方法研究了在１ｍｏｌ．Ｌ＾－１ＫＯＨ溶液中，乙醇在电沉积Ｎｉ－Ｍｏ合金电极上氧化的电化学特性，提出了一个数学模型来预计乙醇在电沉积Ｎｉ－Ｍｏ合金电极上的电化学行为，在碱性溶液中，Ｎｉ（ＯＨ）２／ＮｉＯＯＨ电对的氧化还原过程是乙醇氧化的前期步骤，Ｎｉ（ＯＨ）２／ＮｉＯＯＨ）电对相应的速度常数（即ｋ１和ｋ－１）是电极电位的函数，乙醇氧化是通过一个速度常数为ｋｃ１的化学反应来完成，推导出了各个动力学方程并将实验数据与方程进行比较而获得各个动力学参数，电化学速度常数ｋ１（Ｅ）＝１．４１＊１０＾７ｅｘｐ（０．５ＦＥ／ＲＴ）ｍｍｏｌ．ｃｍ＾－２．ｓ＾－１以及ｋ－１（Ｅ）＝０．７１１ｅｘｐ（０．５ＦＥ／ＲＴ）ｍｍｏｌ．ｃｍ＾－２．ｓ＾－１，Ｅ是相对饱和甘汞电极（ＳＣＥ）的电极电位，而化学反应的速

Kinetic Model of Ethanol Oxidation on Ni-Mo Alloy Electrode

Ni-Mo alloy electrode,prepared by electrodeposition,were characterized for application to ethanol oxidation in 1 mol· L－1 KOH solution.Their electrochemical behavior was studied using cyclic voltammograms and quasi-steady-state current-potential curves.A mathematical model was developed to predict the behavior of ethanol oxidation on Ni-Mo alloy electrodes.The redox of Ni(OH)2/NiOOH couples in the alkaline solution is a preludial step for the ethanol electrooxidation,and the rate constants related to this reaction,k1 as well k－1,are functions of applied potential.Ethanol oxidation is carried out by a chemical reaction with rate constant kC1.The kinetic equations were derived and the kinetic parameters were obtained from a comparison of experimental results with kinetic equations.The rate constants of electrochemical reactions could be expressed as k1(E) =1.41× 107exp(0.5FE/RT)mmol· cm－2· s－1,k－1(E)=0.711 exp(0.5 FE/RT) mmol· cm－2· s－1,in which E was the applied potential vs SCE,and the chemical reaction rate constant,kC1,was 1.99× 10－4 cm· s－ 1.