A density functional theory study of formaldehyde adsorption and oxidation on CeO2(111) 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. Oil 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 H-2 form quickly with low energy barriers When O-2 adsorbs on the reduced (1 1 1) surface (O-2/O-v 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 O-2 adsorbs on oxygen vacancy at sub-layer surface, its oxidative roles on formaldehyde are much similar to that of O-2/O-v species. (C) 2009 Elsevier B.V. All rights reserved.