Monte Carlo simulation of temperature programmed reaction and surface explosion during CO oxidation on a Pt catalyst

A Monte Carlo model of CO oxidation on a Pt(111) surface that includes finite rates of adsorption-desorption and reaction and the effect of the catalyst temperature is presented. The results show that, as expected from the reaction-adsorption probabilities, the surface coverage changes from being almost completely covered by CO at low temperature (60°C), to being completely covered by oxygen at high temperature (160°C). Furthermore, it was found that an unstable state occurs when cooling down the oxygen covered surface from 160°C to 60°C. It is shown that if a site for CO adsorption is created under this metastable state, a surface explosion that propagates spatially occurs. Thus the MC simulations provide a method to describe a catalytic reaction on surfaces with strongly non-linear spatio-temporal dynamics.