K‑Edge X‑ray Absorption Fine Structure Analysis of Pt/Au Core–Shell Electrocatalyst: Evidence for Short Pt–Pt Distance
journal contribution
posted on 2014-04-24, 00:00 authored by Takahiro Kaito, Hisashi Mitsumoto, Seiho Sugawara, Kazuhiko Shinohara, Hiromitsu Uehara, Hiroko Ariga, Satoru Takakusagi, Yoshikiyo Hatakeyama, Keiko Nishikawa, Kiyotaka AsakuraA carbon-supported Pt-shell Au-core
electrocatalyst (Pt/Au/C) was
prepared by sequential deposition of Pt ions on the surface of Au
nanoparticles supported on carbon. The area-specific activity of the
oxygen reduction reaction (ORR) for the prepared Pt/Au/C in 0.1 M
HClO4 aqueous solution was approximately 2 times higher
than that for a commercial carbon-supported Pt electrocatalyst (Pt/C).
The core–shell structure was confirmed using electrochemical
methods and Pt and Au K-edge X-ray absorption fine structure (XAFS)
analysis. XAFS analyses indicated that the Pt–Pt bond distance
for the Pt/Au/C catalyst was shorter than that for Pt foil and the
Pt/C catalyst. In addition, the Au–Au distance was much shorter
than that for Au foil. The reason for the high ORR activity of Pt/Au/C
is considered to be shorter Pt–Pt bond distance as compared
to that of Pt/C.
