Monte carlo simulation of catalytic surface reactions

An overview of the computer simulation work in the field of irreversible catalytic surface reactions being pursued at PINSTECH is presented. An irreversible kinetic surface reaction based upon the oxidation of carbon monoxide exhibits both a second-order and a first order phase transition. We study the time evolution of this reaction near and slightly above the first order transition. It is seen that oxygen concentration, for low coverages, decays exponentially with time. The NO-CO catalytic reaction is also studied on square and hexagonal surfaces. It is shown that the type of the lattice and the dissociation rate of NO are important factors for the reduction (oxidation) of NO (CO). A study reactive state is achieved only when each site has six nearest neighbours (i.e., hexagonal lattice) and this state exists between two critical concentrations of CO for a given value of the dissociation rate. The window width of this steady reactive state is largest when there is complete dissociation and it closes at about 80% dissociation rate. (author)