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, SukWoo Nam, Tae Hoon Lim

Research output: Contribution to journalArticle

3 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

Keywords

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

ASJC Scopus subject areas

  • Surfaces, Coatings and Films

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