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电化学(中英文) ›› 2006, Vol. 12 ›› Issue (4): 368-372. 

• 研究论文 • 上一篇    下一篇

V(Ⅳ)/V(Ⅴ)电对在石墨毡与导电塑料复合电极上的反应机理(英文)

李晓刚;黄可龙;刘素琴;谭宁;陈立泉;   

  1. 中南大学化学化工学院,中南大学化学化工学院,中南大学化学化工学院,中南大学化学化工学院,中南大学化学化工学院 湖南长沙410083,湖南长沙410083,湖南长沙410083,湖南长沙410083,湖南长沙410083,中科院物理所,北京100083
  • 收稿日期:2006-11-28 修回日期:2006-11-28 出版日期:2006-11-28 发布日期:2006-11-28

Reaction Mechanism of V(Ⅳ)/V(Ⅴ) Redox Couple at Graphite Felt Composite Electrode Bonded with Conductive Carbon Plastic

LI Xiao-gang1,HUANG Ke-long*1,LIUSu-qin1,TAN Ning1,CHEN Li-quan1,2   

  1. (1.School ofChemistry and Chemical Engineering,Central South University,Changsha410083,Hunan,China;2.Institute ofPhysics,Chinese Academy ofSciences,Beijing100080,China
  • Received:2006-11-28 Revised:2006-11-28 Published:2006-11-28 Online:2006-11-28

摘要: 应用循环伏安、极化曲线和交流阻抗等电化学方法研究了V(Ⅳ)/V(Ⅴ)电对在石墨毡复合电极上反应的速控步骤.结果表明,V(Ⅳ)/V(Ⅴ)电对在石墨毡电极上的反应属准可逆过程,且氧化过程包含有后置化学转化步骤;该过程Tafel斜率的实验值为0.124,而理论计算的,以电化学步骤作为控制步骤的Tafel斜率约0.12,两者吻合很好,表明该氧化过程受电化学步骤控制;以等效电路拟合不同极化电位下的交流阻抗,得出该电化学反应阻抗远大于其他阻抗,意味着电化学过程可能是电极反应的控制步骤,与实验得到的极化曲线分析结果相一致.

关键词: 石墨毡, 控制步骤, 钒电池, V(Ⅳ)/V(Ⅴ)

Abstract: The rate-determining step of V(Ⅳ) /V(Ⅴ) redoxreaction was investigated at graphite felt(GF)composite electrode by various techniques: cyclic voltammetry,polarization curve and impedance spectroscopy.Cyclic voltammetry analysis indicated that V(Ⅳ) /V(Ⅴ) redox reaction at GF electrode is quasi reversible.Acertain chemical reaction step is suspected to follow the electron transfer step of this reaction.The Tafel slopevalue(0.124) obtained from the polarization curve agrees well with theoretical value(0.12),which supposingthe electron transfer step was the rate-determining step.Impedance Spectroscopies at various potentials werestudied and simulated by equivalentcircuits.The impedance value of the electron transfer step modified is greatlyhigher than the others,which shows that the electron transfer step is the rate-determining step.This further con-firms the conclusion obtained by polarization curve test.

Key words: graphite felt, rate-determining step, vanadium redox battery, V(Ⅳ) / V(Ⅴ)

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