A density functional theory study of formaldehyde adsorption and oxidation on CeO_2(111) surface

摘要

The effects of different oxygen species and vacancies on the adsorption and oxidation of formaldehyde over CeO_2(111) surface were systematically investigated by using density functional theory (DFT) method. On the stoichiometric CeO_2(111) surface, the C-H bond rupture barriers of chemisorbed formaldehyde are much higher than that of formaldehyde desorption. On the reduced CeO_2(111) surface, the energy barriers of C-H bond ruptures are less than those on the stoichiometric CeO_2(111) 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 (111) surface (O_2/O_v species), the C-H bond rupture barriers of formaldehyde are greatly reduced in comparison with those on the stoichiometric CeO_2(111) 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.