Synergistic effects of Cu2O-decorated CeO2 on photocatalytic CO2 reduction: surface Lewis acid/base and oxygen defect

Abstract Ceria (CeO 2 ) with abundant oxygen defects, surface alkalinity, low cost effectiveness and admirable redox ability could be used in the photoreduction of CO 2 . However, little attention has been paid to the interaction of reactant CO 2 molecules on CeO 2 –based photocatalysts. In this work, Cu 2 O nanoparticles were applied to the modification of the properties of Lewis acid/base, surface oxygen defect content and visible light adsorption of CeO 2 , and the adsorption/activation abilities of CO 2 reactant on Cu 2 O/CeO 2 and CeO 2 photocatalysts were investigated in comparison. The photocatalytic performance showed that Cu 2 O/CeO 2 had better activity than CeO 2 . And the loading of Cu 2 O resulted in more oxygen defects and Ce 3+ species, which was helpful for available visible light adsorption and higher charge-separation efficiency. Furthermore, CO 2 -TPD, CO 2 -adsorption DRIFTS and in-situ ESR results demonstrated that the synergistic effects of Cu 2 O/CeO 2 were beneficial for more generated carboxylate and CO 2 − radicals, instead of carbonate species which promoted CO 2 reduction to CO.