Enhancement of O2 dissociation on Au(111) by adsorbed oxygen: Implications for oxidation catalysis

Xingyi Deng, Byoung Koun Min, Amado Guloy, Cynthia M. Friend

Research output: Contribution to journalArticle

188 Citations (Scopus)

Abstract

We show that the dissociation probability of O2 on the reconstructed, Au(111)-herringbone surface is dramatically increased by the presence of some atomic oxygen on the surface. Specifically, at 400 K the dissociation probability of O2 on oxygen precovered Au(111) is on the order of 10-3, whereas there is no measurable dissociation on clean Au(111), establishing an upper bound for the dissociation probability of 10 -6. Atomic oxygen was deposited on the clean reconstructed Au(111)-herringbone surface using electron bombardment of condensed NO 2 at 100 K. The dissociation probability for dioxygen was measured by exposing the surface to 18O2. Temperature programmed desorption (TPD) was used to quantify the amount of oxygen dissociation and to study the stability of the oxygen in all cases. Oxygen desorbs as O2 in a peak centered at 550 K with pseudo-first-order kinetics; i.e., the desorption peak does not shift with coverage. Our interpretation is that the coverage dependence of the activation energy for dissociation (ΔE dis) and/or preexponential factor (υd) may be responsible for the unusual desorption kinetics, implying a possible energy barrier for O2 dissociation on Au(111). These results are discussed in the context of Au oxidation chemistry and the relationship to supported Au nanoparticles.

Original languageEnglish
Pages (from-to)9267-9270
Number of pages4
JournalJournal of the American Chemical Society
Volume127
Issue number25
DOIs
Publication statusPublished - 2005 Jun 29
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)

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