Effect of gold subsurface layer on the surface activity and segregation in Pt/Au/Pt3M (where M = 3 d transition metals) alloy catalyst from first-principles

Chang Eun Kim, Dong Hee Lim, Jong Hyun Jang, Hyoung Juhn Kim, Sung Pil Yoon, Jonghee Han, Suk Woo Nam, Seong Ahn Hong, Aloysius Soon, Hyung Chul Ham

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    28 Citations (Scopus)

    Abstract

    The effect of a subsurface hetero layer (thin gold) on the activity and stability of Pt skin surface in Pt3M 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/Pt3M 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/Pt3M 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 Pt3M 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.

    Original languageEnglish
    Article number034707
    JournalJournal of Chemical Physics
    Volume142
    Issue number3
    DOIs
    Publication statusPublished - 2015 Jan 21

    Bibliographical note

    Publisher Copyright:
    © 2015 AIP Publishing LLC.

    ASJC Scopus subject areas

    • General Physics and Astronomy
    • Physical and Theoretical Chemistry

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