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Title: Communication: Enhanced oxygen reduction reaction and its underlying mechanism in Pd-Ir-Co trimetallic alloys

Based on a combined density functional theory and experimental study, we present that the electrochemical activity of Pd{sub 3}Co alloy catalysts toward oxygen reduction reaction (ORR) can be enhanced by adding a small amount of Ir. While Ir tends to favorably exist in the subsurface layers, the underlying Ir atoms are found to cause a substantial modification in the surface electronic structure. As a consequence, we find that the activation barriers of O/OH hydrogenation reactions are noticeably lowered, which would be mainly responsible for the enhanced ORR activity. Furthermore, our study suggests that the presence of Ir in the near-surface region can suppress Co out-diffusion from the Pd{sub 3}Co substrate, thereby improving the durability of Pd-Ir-Co catalysts. We also discuss the relative roles played by Ir and Co in enhancing the ORR activity relative to monometallic Pd catalysts.
Authors:
;  [1] ;  [2] ; ; ; ;  [3] ;  [4]
  1. Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712 (United States)
  2. Department of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712 (United States)
  3. Energy Lab, Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd., Suwon (Korea, Republic of)
  4. Department of Energy and Mineral Resources Engineering, Sejong University, Seoul 143-747 (Korea, Republic of)
Publication Date:
OSTI Identifier:
22251320
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 139; Journal Issue: 20; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ALLOYS; CATALYSTS; DENSITY FUNCTIONAL METHOD; ELECTRONIC STRUCTURE; HYDROGENATION; OXYGEN; REDUCTION; SUBSTRATES