Microscopic model for the poisoning and promotion of adsorption rates by electronegative and electropositive atoms

A theoretical framework for comparing binding energies and activation energies for adsorption on surfaces based on the effective medium theory is presented. It is applied to a microscopic description of the mechanisms underlying the promotion and poisoning of the molecular adsorption process on metal surfaces by co-adsorbed species. Based on self-consistent calculations of the electronic structure of adsorbed electropositive and electronegative atoms, estimates of the range and strength of this so-called electronic factor in heterogeneous catalysis are made which are in good agreement with recent experimental studies. © 1984.