Role of hydroxyl groups for the O2 adsorption on CeO2 surface: A DFT + U study

Our calculations with spin-polarized density functional theory and on-site Coulomb interactions (DFT + U) have showed that (i) OH groups can facilitate O2 adsorption on CeO2 even at low OH coverages; (ii) the OH groups posses a long-range and coverage effects on the O2 adsorption; and (iii) the adsorbed O2 can readily diffuse along the surface Ce atoms in the presence of OH groups, and this may be a large O2 supply for CO oxidation on the interface of noble-metal/CeO2. We provide the evidence that O2 is supplied by superoxide species on CeO2 in the presence of OH and can diffuse to the interface of noble-metal/CeO2 for CO oxidation.