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

We employed density functional theory (DFT) 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 (Pt1ML) supported on an M surface, Pt1ML/M(111) or (001), was considered as a model system. Different sets of candidate M cores were identified to achieve a stable Pt1ML shell depending on the conditions. In vacuum conditions, the Pt1ML 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 PtML 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 undergo the pathway via *Omore » intermediate. Our results show that PSAs can behave differently from the near surface alloy, Pt1ML/M1ML/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 Pt1ML shell were also discussed.« less
Authors:
 [1] ;  [2] ;  [1] ;  [3] ;  [1]
  1. Jilin Univ., Changchun (China)
  2. Brookhaven National Lab. (BNL), Upton, NY (United States)
  3. Jilin Univ., Changchun (China); Changchun Univ. (China)
Publication Date:
OSTI Identifier:
1213375
Report Number(s):
BNL--108253-2015-JA
Journal ID: ISSN 0021-9606; JCPSA6; KC0403020; TRN: US1500642
Grant/Contract Number:
SC00112704
Type:
Accepted Manuscript
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 142; Journal Issue: 19; Journal ID: ISSN 0021-9606
Publisher:
American Institute of Physics (AIP)
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE Pt monolayer; pseudomorphic surface alloy; acid/alkaline solution; stability; ORR; DFT