NO-CO REACTION ON SQUARE AND HEXAGONAL SURFACES - A MONTE-CARLO SIMULATION

The NOCO catalytic reaction on square and hexagonal surfaces is studied through Monte Carlo (MC) simulation. It is shown that the type of the lattice and the dissociation rate γNO of NO to dissociate into N and O are important factors for the reduction (oxidation) of NO (CO). A steady reactive state is achieved only when each site has six nearest neighbors (i.e., a hexagonal surface) and this state exists between two critical concentrations of CO (or NO) for a given value of rNO. The window width of this steady reactive state is largest when rNO= 1 and it closes at rNO ≤ 0.8. It is shown that there is a scaling law between the window width and the dissociation rate. It is further observed that the surface oxygen from NO reacts somewhat less readily with CO than with the oxygen from dissociated O2, and thus the experimental results previously obtained are confirmed. © 1991.