A density functional theory study of formaldehyde adsorption and oxidation on CeO2(1 1 1) surface

The effects of different oxygen species and vacancies on the adsorption and oxidation of formaldehyde over CeO2(1 1 1) surface were systematically investigated by using density functional theory (DFT) method. On the stoichiometric CeO2(1 1 1) surface, the C–H bond rupture barriers of chemisorbed formaldehyde are much higher than that of formaldehyde desorption. On the reduced CeO2(1 1 1) surface, the energy barriers of C–H bond ruptures are less than those on the stoichiometric CeO2(1 1 1) surface. If the C–H bond rupture occurs, CO and H2 form quickly with low energy barriers. When O2 adsorbs on the reduced (1 1 1) surface (O2/Ov species), the C–H bond rupture barriers of formaldehyde are greatly reduced in comparison with those on the stoichiometric CeO2(1 1 1) surface. If O2 adsorbs on oxygen vacancy at sub-layer surface, its oxidative roles on formaldehyde are much similar to that of O2/Ov species.