Computational investigation of CO adsorption and oxidation on Mn/CeO ₂(111) surface

The interaction and mechanism for CO oxidation on the Mn/CeO ₂(111) surface have been studied by using periodic density functional theory calculations corrected with the on-site Coulomb interaction via a Hubbard term (DFT + U). It is found that the Mn dopant facilitates oxygen vacancy formation, while the Mn adatoms may restrain oxygen vacancy formation. In addition, physisorbed CO, physisorbed CO₂,and chemisorbed CO (carbonite, CO₂^-) species are observed on the Mn-doped CeO₂(111) surface, in contrast, only physisorbed CO is found on the pure CeO₂(111) surface. The vibrational frequency calculations as well as the calculated adsorption energies are carried to characterize these species. The Mn dopant promotes CO oxidation without any activation energy leading to O vacancy formation and CO₂ desorption. The Bader charge analysis is carried to characterize the oxidation state of Mn ions along the catalytic cycle.