title: Low O2 dissociation barrier on Pt(111) due to adsorbate-adsorbate interactions.
abstract: O(2) dissociation on Pt(111) has been followed at low and saturation coverage using temperature-programmed x-ray photoelectron spectroscopy and simulated with mean-field kinetic modeling, yielding dissociation (E(a)) and desorption (E(d)) barriers of 0.32 and 0.36 eV, respectively. Density functional theory calculations show that E(a) is strongly influenced by the O-O interatomic potential in the atomic final state: of the supercells considered, that which maximizes attractive third-nearest-neighbor interactions in the atomic final state yields both the lowest computed dissociation barrier (0.24 eV) and the best agreement with experiment. It is proposed that the effect of adsorbate-adsorbate interactions must be considered when modeling catalytic processes involving dissociative steps.
authors.affiliation: Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Rd, Menlo Park, California 94025, USA.
authors.forename: D J
authors.initials: DJ
authors.lastname: Miller
authors.forename: H
authors.initials: H
authors.lastname: Öberg
authors.forename: L-Å
authors.initials: LÅ
authors.lastname: Näslund
authors.forename: T
authors.initials: T
authors.lastname: Anniyev
authors.forename: H
authors.initials: H
authors.lastname: Ogasawara
authors.forename: L G M
authors.initials: LG
authors.lastname: Pettersson
authors.forename: A
authors.initials: A
authors.lastname: Nilsson