Interaction of oxygen with the Pt(111) surface: a cluster model study

The chemisorption of oxygen on Pt(111) was studied using ab initio molecular orbital and density functional methods. The cluster model with Pt atoms fixed at bulk lattice sites was employed for modelling a Pt surface where the Pt atoms were described by relativistic effective core potentials. Results for the atomic oxygen adsorption energy at a three-fold hollow site of a Pt3 cluster obtained for MP2 and DFT calculations are comparable with experimental ones, but the predicted Pt-O bond length is considerably too long. The study of the oxygen molecule on such surface models confirms that dissociation adsorption occurs and an orientation with the molecular axis parallel to the surface plane is preferred.