"Low O2 dissociation barrier on Pt(111) due to adsorbate–adsorbate interactions"

D. J. Miller: H. Öberg, L.-Å. Näslund, T. Anniyev, H. Ogasawara, L. G. M. Pettersson, and A. Nilsson; The Journal of Chemical Physics, 12/10/10.

Additional Authors: H. Öberg, L.-Å. Näslund, T. Anniyev, H. Ogasawara, L. G. M. Pettersson, and A. Nilsson

Abstract:

O2 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 (Ea) and desorption (Ed) barriers of 0.32 and 0.36 eV, respectively. Density functional theory calculations show that Ea 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.