Potential oscillations in galvanostatic electrooxidation of formic acid on platinum: A time-resolved surface-enhanced infrared study

Gabor Samjeské, Atsushi Miki, Shen Ye, Akira Yamakata, Yoshiharu Mukouyama, Hiroshi Okamoto, Masatoshi Osawa

研究成果: Article査読

146 被引用数 (Scopus)

抄録

The mechanism of temporal potential oscillations that occur during galvanostatic formic acid oxidation on a Pt electrode has been investigated by time-resolved surface-enhanced infrared absorption spectroscopy (SEIRAS). Carbon monoxide (CO) and formate were found to adsorb on the surface and change their coverages synchronously with the temporal potential oscillations. Isotopic solution exchange (from H13COOH to H12COOH) and potential step experiments revealed that the oxidation of formic acid proceeds dominantly through adsorbed formate and the decomposition of formate to CO 2 is the rate-determining step of the reaction. Adsorbed CO blocks the adsorption of formate and also suppresses the decomposition of formate to CO2, which raises the potential to maintain the applied current. The oxidative removal of CO at a high limiting potential increases the coverage of formate and accelerates the decomposition of formate, resulting in a potential drop and leading to the formation of CO. This cycle repeats itself to give the sustained temporal potential oscillations. The oscillatory dynamics can be explained by using a nonlinear rate equation originally proposed to explain the decomposition of formate and acetate on transition metal surfaces in UHV.

本文言語English
ページ(範囲)23509-23516
ページ数8
ジャーナルJournal of Physical Chemistry B
109
49
DOI
出版ステータスPublished - 2005 12月 15
外部発表はい

ASJC Scopus subject areas

  • 物理化学および理論化学
  • 表面、皮膜および薄膜
  • 材料化学

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