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

g-C₃N₄ quantum dots (CN QDs)-decorated mesoporous CeO₂ composite photocatalyst was prepared by hydrothermal method. The characterized results exhibit that the CN QDs are successfully coupled with mesoporous CeO₂, and the photoelectronic response is effectively enhanced. The photocatalytic activity was tested by CO₂ 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 CH₄ were 22.48 µmol/g and 15.81 µmol/g, respectively. Some of the electrons generated within m-CeO₂ participated in the CO₂ reduction reaction and some were transferred to CN QDs through the two-phase interface to participate in the CO₂ catalytic reaction. The oxygen vacancies in m-CeO₂ can adsorb CO₂ and the introduced CN QDs can excite more oxygen vacancies with m-CeO₂ heterostructure, thereby adsorbing more CO₂ and photoreduction electrons. [ABSTRACT FROM AUTHOR]