Computational Investigation of CO Adsorption and Oxidation on Mn/CeO2(111) Surface

The interaction and mechanism for CO oxidation on the Mn/ CeO2(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.