Preferential occurrence of carbon monoxide oxidation on two reaction sites on platinum (113)

Spatial distribution measurements of desorbing product CO2 confirm that two kinds of reaction sites are operative on a stepped platinum (113) surface. With increasing reactant coverages, the collimation angle of CO2 desorption is shifted from a desorption angle of −17° to one of +21° in the direction of up-and-down steps. Reaction sites yielding the above collimations are assigned to be on steps of a (001) structure and on terraces of a (111) structure, respectively.