Simulation of kinetic oscillations in catalytic reactions accompanied by oxide formation

One of the generic mechanisms of oscillations in heterogeneous catalytic reactions with participation of oxygen is based on slow oxidation and reduction of the metal surface. We present Monte Carlo simulations of spatiotemporal patterns corresponding to this mechanism. As an example, we analyze the 2A + B-2 --> 2AB reaction mimicking CO (or H-2) oxidation on Pt. Calculations taking into account the nonideality of the kinetics of oxidation and reduction of the substrate are executed with a qualitatively realistic ratio of the rates of elementary steps. The results obtained indicate that the reaction scheme under consideration possesses the ability of spatial self-organization even if cooperative effects in nucleation, growth and decay of oxide islands are neglected. In this case, however, the islands are small and rather disordered. With the cooperative effects, the size of islands becomes larger but not dramatically. A very strong tendency to form oxide islands is found to suppress oscillations.