Self-oscillations and chemical waves in CO oxidation on Pt and Pd: Kinetic Monte Carlo models

Theoretical studies of the spatiotemporal dynamics of CO oxidation on Pt(100) and Pd(110) single crystal surfaces have been carried out by the kinetic Monte Carlo method. For both surfaces, Monte Carlo simulation has revealed oscillations of the CO₂ formation rate and of the concentrations of adsorbed species. The oscillations are accompanied by wave processes on the model surface. Simulations have demonstrated that there is a narrow reaction zone when an oxygen wave propagates over the surface. The existence of this zone has been confirmed by experimental studies. Taking into account the anisotropy of the Pd(110) crystal has no effect on the oscillation period and amplitude, but leads to the formation of elliptic oxygen patterns on the surface. It is possible to obtain a wide variety of chemical waves (cellular and turbulent structures, spirals, rings, and strips) by varying the parameters of the computational experiment.