Surface restructuring and aperiodic kinetic oscillations in heterogeneous catalytic reactions

We present comprehensive Monte Carlo simulations of aperiodic kinetic oscillations in catalytic reactions accompanied by adsorbate-induced surface restructuring. Our analysis, focused on the NO–H2 reaction on Pt(1 0 0), is based on a lattice-gas model describing surface restructuring in terms of the statistical theory of first-order phase transitions. The oscillations predicted are proved to be robust. In particular, the type of irregularities observed in the reaction kinetics is nearly independent of the used boundary conditions and does not change upon increasing the rate of adsorbate diffusion. On the other hand, the kinetics are found to be very sensitive to small perturbations in the arrangement of adsorbed particles. Specifically, the divergence of the kinetic curves corresponding to slightly different initial conditions occurs very rapidly. The latter indicates that the oscillations obtained can be classified as chaotic.