Ordering and oxygen adsorption in Au-Pt/Pt(111) surface alloys

Wei Chen*, David Schmidt, William F. Schneider, C. Wolverton

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

30 Scopus citations

Abstract

Bimetallic surface alloys are considered a promising type of catalyst for improved activity and selectivity. Using first-principles density functional calculations and the cluster expansion (CE) method, we have studied the surface structure and ordering of a mixed Au-Pt surface layer on Pt(111). Even though the Au-Pt system is well-known to phase-separate in the bulk, we predict a series of T = 0 K energetically stable, laterally ordered striped structures in the Au-Pt(111) surface. The formation of such ordered structures is the result of a competition between the strain relaxations (favoring short-period stripe ordering) and the unfavorable Au-Pt bonds at stripe interfaces (favoring long-period phase separation). We have also investigated the oxygen adsorption on these ordered structures and a disordered Au-Pt(111) surface alloy. The disordered surface is modeled by a two-dimensional special quasirandom structure (SQS) that mimics the pair and triplet correlation functions of a disordered binary distribution. The oxygen binding energy is highly correlated with the number and type of the nearest neighbor metal surface atoms to the adsorbed oxygen.

Original languageEnglish (US)
Pages (from-to)17915-17924
Number of pages10
JournalJournal of Physical Chemistry C
Volume115
Issue number36
DOIs
StatePublished - Sep 15 2011

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

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