A transient kinetics study of the reaction of CO with chemisorbed oxygen on platinum

Abstract

Transient pressure-jump experiments are reported in which the reaction between gas phase carbon monoxide and chemisorbed oxygen on polycrystalline platinum is followed using both CO2 decay and CO titration methods. The experiments are carried out at 540 °K and low pressures below 5×10−7 torr. From the data we conclude that the reaction between chemisorbed oxygen atoms and gas phase carbon monoxide is first order in CO pressure and, at high oxygen atom coverages, zero order in the adsorbed oxygen atom concentration. These results imply that CO impinging on the platinum surface visits several sites during the course of a single encounter.