Model building analysis-a novel method for statistical evaluation of Pt L3-edge EXAFS data to unravel the structure of Pt-alloy nanoparticles for the oxygen reduction reaction on highly oriented pyrolytic graphite

Felix E. Feiten, Shuntaro Takahashi, Oki Sekizawa, Yuki Wakisaka, Tomohiro Sakata, Naoto Todoroki, Tomoya Uruga, Toshimasa Wadayama, Yasuhiro Iwasawa, Kiyotaka Asakura

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

Extended X-ray absorption fine structure (EXAFS) is a powerful tool to determine the local structure in Pt nanoparticles (NP) on carbon supports, active catalysts for fuel cells. Highly oriented pyrolytic graphite (HOPG) covered with Pt NP gives samples with flat surfaces that allow application of surface science techniques. However, the low concentration of Pt makes it difficult to obtain good quality EXAFS data. We have performed in situ highly sensitive BCLA-empowered Back Illuminated EXAFS (BCLA + BI-EXAFS) measurements on Pt alloy nanoparticles. We obtained high quality Pt L3-edge data. We have devised a novel analytical method (model building analysis) to determine the structure of multi-component nanoparticles from just a single absorption edge. The generation of large numbers of structural models and their comparison with EXAFS fits allows us to determine the structures of Pt-containing nanoparticles, catalysts for the oxygen reduction reaction. Our results show that PtCo, PtCoN and AuPtCoN form a Pt-shell during electrochemical dealloying and that the ORR activity is directly proportional to the Pt-Pt bond length.

Original languageEnglish
Pages (from-to)18815-18823
Number of pages9
JournalPhysical Chemistry Chemical Physics
Volume22
Issue number34
DOIs
Publication statusPublished - 2020 Sep 14

ASJC Scopus subject areas

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

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