CO oxidation on Rh(100): Multisite atomistic lattice-gas modeling

A detailed multisite atomistic lattice-gas model is applied for CO oxidation on single-crystal Rh(100) surfaces 14 under low-pressure conditions. Its behavior is analyzed by kinetic Monte Carlo simulation accounting for high adspecies surface mobility. The model input includes binding energies and interactions for CO and oxygen adspecies as well as a prescription of the adsorption-desorption dynamics and of the reaction pathway and energetics. Density functional theory (DFT) provides some guidance as to these energies, but significant uncertainties remain, particularly regarding the CO binding site on Rh(100). Thus, most modeling is performed with a judiciously chosen set of energetics in light of existing experimental evidence. We examine (i) the ordering and temperature-programmed desorption kinetics of the individual reactant adspecies, CO and oxygen, on Rh(100) and (ii) ordering in the mixed reactant adlayer and CO oxidation kinetics as reflected in temperature-programmed reaction spectra.