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Title: Stabilization of Pt monolayer catalysts under harsh conditions of fuel cells

We employed density functional theory to explore the stability of core (M = Cu, Ru, Rh, Pd, Ag, Os, Ir, Au)-shell (Pt) catalysts under harsh conditions, including solutions and reaction intermediates involved in the oxygen reduction reaction (ORR) in fuel cells. A pseudomorphic surface alloy (PSA) with a Pt monolayer (Pt{sub 1ML}) supported on an M surface, Pt{sub 1ML}/M(111) or (001), was considered as a model system. Different sets of candidate M cores were identified to achieve a stable Pt{sub 1ML} shell depending on the conditions. In vacuum conditions, the Pt{sub 1ML} shell can be stabilized on the most of M cores except Cu, Ag, and Au. The situation varies under various electrochemical conditions. Depending on the solutions and the operating reaction pathways of the ORR, different M should be considered. Pd and Ir are the only core metals studied, being able to keep the Pt{sub ML} shell intact in perchloric acid, sulfuric acid, phosphoric acid, and alkaline solutions as well as under the ORR conditions via different pathways. Ru and Os cores should also be paid attention, which only fall during the ORR via the *OOH intermediate. Rh core works well as long as the ORR does not undergomore » the pathway via *O intermediate. Our results show that PSAs can behave differently from the near surface alloy, Pt{sub 1ML}/M{sub 1ML}/Pt(111), highlighting the importance of considering both chemical environments and the atomic structures in rational design of highly stable core-shell nanocatalysts. Finally, the roles that d-band center of a core M played in determining the stability of supported Pt{sub 1ML} shell were also discussed.« less
Authors:
; ;  [1] ;  [1] ;  [2] ;  [3]
  1. Department of Materials Science, Key Laboratory of Mobile Materials, MOE, and State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012 (China)
  2. (China)
  3. Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973 (United States)
Publication Date:
OSTI Identifier:
22415811
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 142; Journal Issue: 19; Other Information: (c) 2015 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; CATALYSTS; COPPER; DENSITY FUNCTIONAL METHOD; ELECTROCHEMISTRY; FUEL CELLS; GOLD; OSMIUM; OXYGEN; PERCHLORIC ACID; PHOSPHORIC ACID; PLATINUM; REACTION INTERMEDIATES; REDUCTION; RHODIUM; SOLUTIONS; STABILIZATION; SULFURIC ACID; SURFACES