物理化学学报 >> 2000, Vol. 16 >> Issue (11): 1013 -1021 .doi: 10.3866/PKU.WHXB20001110

研究论文 上一篇    下一篇

乙醇在Ni-Mo合金电极上氧化的动力学模型

曾跃, 于尚慈, 李则林, 陈珂, 周绍民   

  1. 湖南师范大学化学系 长沙 410006|固体表面物理化学国家重点实验室,厦门大学化学系 厦门 361005
  • 收稿日期:2000-02-16 修回日期:2000-06-07 发布日期:2000-11-15
  • 通讯作者: 曾跃

Kinetic Model of Ethanol Oxidation on Ni-Mo Alloy Electrode

Zeng Yue, Yu Shang-Ci, Li Ze-Lin, Chen Ke, Zhou Shao-Min   

  1. Department of Chemistry,Hunan Normal University,Changsha,Hunan 410006|State Key Laboratory for Physical Chemistry of the Solid Surface,Department of Chemistry,Xiamen University,Xiamen 361005
  • Received:2000-02-16 Revised:2000-06-07 Published:2000-11-15
  • Contact: Zeng Yue

摘要:

利用循环伏安以及稳态极化曲线等方法研究了在 1 mol• L- 1 KOH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× 107exp(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 .而化学反应的速度常数 kC1=1.99× 10- 4 cm• s- 1.

关键词: Ni-Mo合金, 乙醇氧化, 动力学, 数学模型

Abstract:

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.

Key words: Ni-Mo alloy, Ethanol oxidation, Kinetics, Mathematical model