Oscillatory oxidation of CO on Pt(100): Monte Carlo simulations

We apply a comprehensive Monte Carlo simulation for the-global oscillations in the CO catalytic oxidation system on the Pt(100) surface based on a well defined lattice gas model. The basic reactive steps of the present model follow the Langmuir-Hinshelwood mechanism incorporated with adsorbate--induced surface restructuring which follows the statistical theory of first-order phase transitions. It is shown that oscillation only exists in a certain range of CO fraction in gas and the production rate of CO2 forms a double-periodic oscillation, while the coverages of CO and O-2. and fraction of (1 x 1) phase are in single-periodic oscillation. We give an explanation for these phenomena. Moreover, the simulation results clearly show that the diffusion of adsorbed CO works to synchronize local oscillators and the oscillation in the system will disappear with the decrease of the diffusion.