Formaldehyde as an air pollutant to adverse health effects for humanity has been getting attention.The adsorption and dissociation of formaldehyde(HCHO)on the CoxCe1-xO2-δ(110)surface were investigated by the density functional theory(DFT)calculations.We calculated the oxygen vacancy formation energy as the function of its site around dopant Co in detail.The results showed that Co doping was accompanied by compensating oxygen hole spontaneous formation.The adsorption configurations and bindings of HCHO at different locations on the CoxCe1-xO2(110)were presented.Four possible pathways of oxidation of formaldehyde on the catalytic surface were explored.The results suggested that formaldehyde dissociation at different adsorption sites on the doped CeO2(110)-first forming dioxymethylene(CH2O2)intermediate,and then decomposing into H2O,H2,CO2,and CO molecules.It was found that the presence of cobalt and oxygen vacancy significantly prompted the surface activity of CeO2.