Structural kinetics of a Pt/C cathode catalyst with practical catalyst loading in an MEA for PEFC operating conditions studied by in situ time-resolved XAFS

Nozomu Ishiguro, Takahiro Saida, Tomoya Uruga, Oki Sekizawa, Kensaku Nagasawa, Kiyofumi Nitta, Takashi Yamamoto, Shin Ichi Ohkoshi, Toshihiko Yokoyama, Mizuki Tada

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

The structural kinetics of surface events on a Pt/C cathode catalyst in a membrane electrode assembly (MEA) with a practical catalyst loading (0.5 mg Pt cm-2) for a polymer electrolyte fuel cell were investigated by in situ time-resolved X-ray absorption fine structure analysis (XAFS; time resolution: 100 ms) for the first time. The rate constants of structural changes in the Pt/C cathode catalyst in the MEA during voltage cycling were successfully estimated. For voltage-cycling processes, all reactions (electrochemical reactions and structural changes in the Pt catalyst) in the MEA were found to be much faster than those in an MEA with a thick cathode catalyst layer, but the in situ time-resolved XAFS analysis revealed that significant time lags similarly existed between the electrochemical reactions and the structural changes in the Pt cathode catalyst. The time-resolved XAFS also revealed differences in the structural kinetics of the Pt/C cathode catalyst for the voltage-cycling processes under N2 and air flows at the cathode.

Original languageEnglish
Pages (from-to)18827-18834
Number of pages8
JournalPhysical Chemistry Chemical Physics
Volume15
Issue number43
DOIs
Publication statusPublished - 2013 Nov 21
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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