Predictive Beyond-Mean-Field Rate Equations for Multisite Lattice–Gas Models of Catalytic Surface Reactions: CO Oxidation on Pd(100)

Abstract

Tailored multisite lattice-gas (msLG) models are developed for CO-oxidation on Pd(100) at low-pressures. These models include multiple adsorption site types and superlattice adlayer ordering due to short-range exclusion for highly mobile reactant adspecies. However, they are simplified to neglect longer-range weaker adspecies interactions, so that the key energetic parameters are the CO desorption barrier and the reaction barrier. We discuss existing Density Functional Theory results for these energies, and present additional analysis for CO adsorption. After also including an appropriate non-trivial specification of the dynamics of adsorption onto mixed reactant adlayers, rate equations are developed for the reaction kinetics. Our formulation goes beyond traditional mean-field (MF) Langmuirian treatments by accounting for multiple adsorption sites and for the strong spatial correlations associated with superlattice ordering. Specifically, we utilize factorization approximations based on appropriate site ...