高等学校化学学报 ›› 2005, Vol. 26 ›› Issue (4): 715.

• 研究论文 • 上一篇    下一篇

PtRu/C催化剂上甲醇电氧化的电化学阻抗谱

武刚, 李莉, 徐柏庆   

  1. 清华大学化学系, 有机光电子与分子工程教育部重点实验室分子催化与定向转化研究室, 北京 100084
  • 收稿日期:2004-05-24 出版日期:2005-04-10 发布日期:2005-04-10
  • 通讯作者: 徐柏庆(1961年出生),男,教授,博士生导师,从事多相催化与电催化研究.E-mail:bqxu@mail.tsinghua.edu.cn E-mail:bqxu@mail.tsinghua.edu.cn
  • 基金资助:

    国家重点基础理论研究发展计划“九七三”项目(批准号:G2000026408);中国博士后科学基金(批准号:20040350300);国家自然科学基金(批准号:20125310)资助.

Electrochemical Impedance Spectroscopy of Methanol Electrooxidation on PtRu/C Catalysts

WU Gang, LI Li, XU Bo-Qing   

  1. Innovative Catalysis Program, Key Lab of Organic Optoelectronics & Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing 100084, China
  • Received:2004-05-24 Online:2005-04-10 Published:2005-04-10

摘要: 利用电化学阻抗谱(EIS)研究了甲醇在不同电化学极化处理后的PtRu/C催化剂上的电氧化动力学参数.通过交流阻抗理论的分析,从理论上研究了不同电势区间(低、中、高)内反应中间产物的表面覆盖率随电极电势的变化规律以及对反应法拉第电流的影响,较好地解释了甲醇电氧化实验中的动力学规律在低电势区,甲醇分子脱除第一个氢原子的基元反应,即第一个电子的传递反应为速率控制步骤,而在高电势区,反应中间产物COads的氧化脱除则为速率控制步骤.

关键词: 甲醇, 电氧化, PtRu/C催化剂, 交流阻抗谱

Abstract: The kinetic parameters of methanol electrooxidation on PtRu/C catalysts were investigated by electrochemistry impedance spectroscopy(EIS). The results from EIS at various potentials reveal that the cathodic polarization would contribute to enhancing methanol electrooxidation activity. The impedance behavior of methanol electrooxidation on PtRu/C catalysts at different potentials can be well explained by using the deduced kinetic theory involving one intermediate adsorbate. At low potentials, splitting of the first C-H bond of CH3OH molecule with the first electron transfer is rate-determining step on various PtRu/C electrocatalysts, while at higher potentials, the oxidation reaction of CO<sup>ads gradually becomes rate-determining step. The change of intermediate CO<sup>ads-coverage and its effect on faradic current of methanol electrooxidation were also discussed according to experimental and theoretical results from EIS.

Key words: Methanol, Electrooxidation, PtRu/C catalyst, A.C. impedance spectroscopy

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