Role of cerium oxide in the enhancement of activity for the oxygen reduction reaction at Pt-CeO nanocomposite electrocatalyst; An in situ electrochemical X-ray absorption fine structure study

Masuda, Takuya*; Fukumitsu, Hitoshi*; Fugane, Keisuke*; Togasaki, Hirotaka*; Matsumura, Daiju; Tamura, Kazuhisa; Nishihata, Yasuo; Yoshikawa, Hideki*; Kobayashi, Keisuke*; Mori, Toshiyuki*; et al.

Journal of Physical Chemistry C, 116(18), p.10098 - 10102, 2012/05

https://doi.org/10.1021/jp301509t

In situ electrochemical X-ray absorption fine structure (XAFS) measurements were performed at the Pt L and Ce L edges of the Pt-CeO/C catalyst, which was prepared by a combined process of precipitation and coimpregnation methods, as well as at the Pt L edge of the conventional Pt/C catalyst in oxygen-saturated HSO solution to clarify the role of CeO in the reduction of the overpotential for the oxygen reduction reaction (ORR) at the Pt-CeO nanocomposite compared with the conventional Pt/C catalyst. XAFS measurements clearly show that the enhancement of ORR activity is attributed to the inhibition of Pt oxide formation by the CeO layer, of which Ce was oxidized to Ce instead of Pt at the Pt oxide formation potential.