A density functional theory study of formaldehyde adsorption and oxidation on CeO2(1Â 1Â 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.