title: How low can you go? Minimum energy pathways for O2 dissociation on Pt(111).
abstract: Many DFT studies of O(2) dissociation on Pt(111) give conflicting information on preferred paths and final states. Here we report large p(4 × 4) unit cell minimum energy pathway evaluations and compare O(2) adsorption and dissociated states on Pt(111). Calculations reveal how the pathways for O(2) dissociation starting from top-fcc-bridge, top-hcp-bridge, and top-bridge-top sites are interconnected. They also provide a direct reaction pathway for the dissociation of an O(2) molecule from a top-fcc-bridge into an hcp and an fcc site, which is consistent with low temperature scanning tunneling microscope experiments. Such a pathway is shown to be considerably perturbed by the presence of co-adsorbed oxygen atoms. We quantify the coverage dependence through the construction of a Brønsted-Evans-Polanyi relationship relating the O(2) dissociation activation energies to the binding energies of the dissociated O atoms. We also show that all pathways starting from a top-fcc-bridge site give the smallest barriers for O(2) dissociation.
authors.affiliation: The Gene and Linda Voiland School of Chemical and Bioengineering, Washington State University, Pullman, Washington 99164, USA.
authors.forename: J-S
authors.initials: JS
authors.lastname: McEwen
authors.forename: J M
authors.initials: JM
authors.lastname: Bray
authors.forename: C
authors.initials: C
authors.lastname: Wu
authors.forename: W F
authors.initials: WF
authors.lastname: Schneider