Study of the “explosive” NOÂ +Â CO reaction on a Pt(1Â 0Â 0) surface by dynamic Monte Carlo simulation

The so-called “surface explosion” observed through TPR experiments in the catalytic reduction of NO by CO on a Pt(1 0 0) surface is studied by using a dynamic Monte Carlo method on a square lattice at low pressure conditions. This analysis takes into account recent experimental evidences concerning the above reaction on a Rh(1 1 1) surface; such experiments have shown that the N2 production occurs either from the classical N + N recombination step or by the formation and successive decay of a (N-NO)* intermediary species, being the last step the fastest pathway. Moreover, the effect on NO dissociation rate, i.e., the limiting step during the whole reaction, is inhibited by co-adsorbed NO and CO molecules and is enhanced both by the presence of empty sites and adsorbed N atoms as nearest-neighbors. In these simulations the experimental parameter values are included, such as adsorption, desorption and diffusion rates of the reactants. The “explosive” phenomenon is studied in the temperature range of 300-550 K. In our results, as the surface is totally covered with the adsorbates, cellular structures are observed.