g-C3N4 quantum dots-modified mesoporous CeO2 composite photocatalyst for enhanced CO2 photoreduction

g-C 3 N 4 quantum dots (CN QDs)-decorated mesoporous CeO 2 composite photocatalyst was prepared by hydrothermal method. The characterized results exhibit that the CN QDs are successfully coupled with mesoporous CeO 2 , and the photoelectronic response is effectively enhanced. The photocatalytic activity was tested by CO 2 reduction, and the results showed that when the loading of CN QDs was 0.75 wt%, the composite photocatalyst has the best photocatalytic activity. After 10 h of UV irradiation, the yields of CO and CH 4 were 22.48 µmol/g and 15.81 µmol/g, respectively. Some of the electrons generated within m-CeO 2 participated in the CO 2 reduction reaction and some were transferred to CN QDs through the two-phase interface to participate in the CO 2 catalytic reaction. The oxygen vacancies in m-CeO 2 can adsorb CO 2 and the introduced CN QDs can excite more oxygen vacancies with m-CeO 2 heterostructure, thereby adsorbing more CO 2 and photoreduction electrons.