Toward a realistic model for the kinetics of the NOÂ +Â CO reaction on rhodium surfaces

A model for the kinetics of NO reduction by CO on Rh(1 1 1) surfaces is proposed that takes into account the formation of N-islands in the adsorbed phase, an increase of the NO dissociation probability with the number of neighboring vacant sites, and the blocking of NO dissociation due to the presence of neighboring coadsorbed NO and CO species. The effect and importance of each elementary process in the reaction kinetics is discussed.