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Title: Effect of gold subsurface layer on the surface activity and segregation in Pt/Au/Pt{sub 3}M (where M = 3d transition metals) alloy catalyst from first-principles

The effect of a subsurface hetero layer (thin gold) on the activity and stability of Pt skin surface in Pt{sub 3}M system (M = 3d transition metals) is investigated using the spin-polarized density functional theory calculation. First, we find that the heterometallic interaction between the Pt skin surface and the gold subsurface in Pt/Au/Pt{sub 3}M system can significantly modify the electronic structure of the Pt skin surface. In particular, the local density of states projected onto the d states of Pt skin surface near the Fermi level is drastically decreased compared to the Pt/Pt/Pt{sub 3}M case, leading to the reduction of the oxygen binding strength of the Pt skin surface. This modification is related to the increase of surface charge polarization of outmost Pt skin atoms by the electron transfer from the gold subsurface atoms. Furthermore, a subsurface gold layer is found to cast the energetic barrier to the segregation loss of metal atoms from the bulk (inside) region, which can enhance the durability of Pt{sub 3}M based catalytic system in oxygen reduction condition at fuel cell devices. This study highlights that a gold subsurface hetero layer can provide an additional mean to tune the surface activity toward oxygen speciesmore » and in turn the oxygen reduction reaction, where the utilization of geometric strain already reaches its practical limit.« less
Authors:
 [1] ;  [2] ;  [1] ;  [2] ; ; ; ; ;  [1] ;  [1] ;  [2] ;  [3] ;  [1] ;  [4]
  1. Fuel Cell Research Center, Korea Institute of Science and Technology (KIST), 39-1 Hawolgok, Seongbuk-gu, Seoul 136-791 (Korea, Republic of)
  2. (Korea, Republic of)
  3. Global E3 Institute and Department of Materials Science and Engineering, Yonsei University, 120-749 Seoul (Korea, Republic of)
  4. (UST), 217 Gajungro, Yuseong-gu, Daejeon 305-333 (Korea, Republic of)
Publication Date:
OSTI Identifier:
22416025
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 142; Journal Issue: 3; 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; ATOMS; CATALYSTS; COMPARATIVE EVALUATIONS; D STATES; DENSITY FUNCTIONAL METHOD; DENSITY OF STATES; ELECTRON TRANSFER; ELECTRONIC STRUCTURE; FERMI LEVEL; GOLD; HARDNESS; LAYERS; PLATINUM; PLATINUM ALLOYS; POLARIZATION; SEGREGATION; SPIN ORIENTATION; STRAINS; TRANSITION ELEMENT ALLOYS; WEAR RESISTANCE