Enhancement of oxygen reduction reaction on PtAu nanoparticles via CO induced surface Pt enrichment

Authors:  Hee-Young Park, Tae-Yeol Jeon, Jong Hyun Jang, Sung Jong Yoo, Kwang-Hyun Choi, Namgee Jung, Yung-Hoon Chung, Minje Ahn, Yong-Hun Cho, Kug-Seung Lee, Yung-Eun Sung

Abstract: 
To investigate the enhancement of the oxygen reduction reaction (ORR) activity on a carbon-supported PtAu alloy nanoparticle catalyst, the catalyst was subject to heat treatment at 423K under a CO or Ar atmosphere. The surface composition was analyzed by XPS and the composition was shown to increase from 66 ± 2% (PtAu-AP)to 74 ± 2% (PtAu-CO) after heattreatment under a CO atmosphere, which was confirmed by electrochemical techniques, while the bulk composition was invariant at 55%. For the oxygen reduction reaction (ORR), the mass activity of PtAu-CO increased by 75.6% (33.2 A/gPt) when compared to that of PtAu-AP (18.9 A/gPt). Since the increase in EAS was only 15.8%, it was concluded that the specific activity was enhanced by 52.6% due to surface Pt segregation after heat treatment under a CO atmosphere. The enhanced specific activity was attributed to the reduced OH adsorption energy which was characterized by measuring the potential of total zero charge. The weaker OH adsorption was resulted from the higher Pt/Au ratio at the surface layers.

Keywords:
Polymer electrolyte membrane fuel cell
Electrocatalysis
PtAu
Surface segregation
Pt enrichment
Oxygen reduction reaction

Published in: Applied catalysis B: Environmental  (Volume 129, Pages 1-614, 17 January 2013)

Publisher: Elsevier  

ISSN Information: 0926-3373

Enhancement of oxygen reduction reaction on PtAu nanoparticles via CO induced surface Pt enrichment

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