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

Journal Article · Wed Jan 21 00:00:00 EST 2015 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4905919· OSTI ID:22416025

Kim, Chang-Eun ^[1]; Lim, Dong-Hee ^[1]; Jang, Jong Hyun; Kim, Hyoung Juhn; Yoon, Sung Pil; Han, Jonghee; Nam, Suk Woo ^[1]; Hong, Seong-Ahn ^[1]; Soon, Aloysius ^[2]

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1. Fuel Cell Research Center, Korea Institute of Science and Technology (KIST), 39-1 Hawolgok, Seongbuk-gu, Seoul 136-791 (Korea, Republic of)
2. Global E3 Institute and Department of Materials Science and Engineering, Yonsei University, 120-749 Seoul (Korea, Republic of)

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 species and in turn the oxygen reduction reaction, where the utilization of geometric strain already reaches its practical limit.

• OSTI ID: 22416025
• Journal Information: Journal of Chemical Physics, Vol. 142, Issue 3; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

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