Reaction sites of photo-induced carbon monoxide oxidation on a stepped platinum (113) surface

The reaction sites of CO oxidation induced by 193 nm irradiation were studied in the coadlayer of CO and O2 on Pt(113) = (s)2(111) × (001) around 110 K with the angular and velocity distributions of desorbing product CO2. At low coverages, the CO2 desorption takes place in surface troughs. On the other hand, three kinds of reaction sites are found at high O2 coverage, where three additional desorption components, peaking along the (111) terrace, the (001) step and the bulk surface normal, become predominant.