Chem. J. Chinese Universities ›› 2005, Vol. 26 ›› Issue (4): 715.

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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

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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