Abstract
The catalytic oxidation of CO has already been studied over a square surface through Monte-Carlo simulation via a model based on the Langmuir–Hinshelwood mechanism, in which dissociated adsorption of the O
2
molecule is considered on a pair of vacancies in the nearest neighborhood. The results of this study are well known. Here, we have studied this reaction on the basis of an experimentally observed hot atom mechanism on the Pt (111) surface. According to this mechanism the probability of adsorption of the O
2
molecule on a pair of vacancies in the nearest neighborhood is negligibly small. It is shown that if the two oxygen atoms are adsorbed at two lattice constants apart, then the model yields a steady reactive window where the continuous transition disappears. The production of CO
2
starts the moment CO partial pressure departs from zero, which is seen in the experimental situation.