Role of different Pd/Pt ensembles in determining CO chemisorption on Au-based bimetallic alloys: A first-principles study

Hyung Chul Ham, Dhivya Manogaran, Gyeong S. Hwang, Jonghee Han, Hyoung Juhn Kim, Suk Woo Nam, Tae Hoon Lim

    Research output: Contribution to journalArticlepeer-review

    4 Citations (Scopus)

    Abstract

    Using spin-polarized density functional calculations, we investigate the role of different Pd/Pt ensembles in determining CO chemisorption on Au-based bimetallic alloys through a study of the energetics, charge transfer, geometric and electronic structures of CO on various Pd/Pt ensembles (monomer/dimer/trimer/tetramer). We find that the effect of Pd ensembles on the reduction of CO chemisorption energy is much larger than the Pt ensemble case. In particular, small-sized Pd ensembles like monomer show a substantial reduction of CO chemisorption energy compared to the pure Pd (1 1 1) surface, while there are no significant size and shape effects of Pt ensembles on CO chemisorption energy. This is related to two factors: (1) the steeper potential energy surface (PES) of CO in Pd (1 1 1) than in Pt (1 1 1), indicating that the effect of switch of binding site preference on CO chemisorption energy is much larger in Pd ensembles than in Pt ensembles, and (2) down-shift of d-band in Pd ensembles/up-shift of d-band in Pt ensembles as compared to the corresponding pure Pd (1 1 1)/Pt (1 1 1) surfaces, suggesting more reduced activity of Pd ensembles toward CO adsorption than the Pt ensemble case. We also present the different bonding mechanism of CO on Pd/Pt ensembles by the analysis of orbital resolved density of state.

    Original languageEnglish
    Pages (from-to)409-418
    Number of pages10
    JournalApplied Surface Science
    Volume332
    DOIs
    Publication statusPublished - 2015 Mar 30

    Bibliographical note

    Funding Information:
    This work is supported by the Welch Foundation ( F-1535 ) and KIST institutional program for Korea Institute of Science and Technology . The authors would also like to thank the Texas Advanced Computing Center for use of their computing resources.

    Publisher Copyright:
    © 2015 Elsevier B.V. All rights reserved.

    Keywords

    • AuPd
    • AuPt
    • CO adsorption
    • Ensembles
    • First-principles

    ASJC Scopus subject areas

    • General Chemistry
    • Condensed Matter Physics
    • General Physics and Astronomy
    • Surfaces and Interfaces
    • Surfaces, Coatings and Films

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