Coverage-Dependent CO Adsorption Energy from First-Principles Calculations

CO saturation coverage on Pt(111) is crucially important in diesel oxidation catalysis. We systematically studied coverage-dependent CO adsorption on the Pt(111) surface using density functional theory (DFT) calculations and classical Monte-Carlo (MC) simulations. The zero-coverage-limit CO-adsorption energies at different binding sites are almost degenerate at the revised Perdew-Burke-Erzernhof functional (RPBE) level. As the CO coverage increases, strong through-space repulsion and substrate-mediated metal-sharing effects tend to dominate the stability of adsorbates and alter their binding preferences. The calculated differential binding energy curve and adsorption patterns compare well with experiments.