High-performance photocatalytic reduction of CO2 to CO by defective g-C3N4/CeO2 under sacrificial agent-free conditions☆

Solar energy can be used to convert CO 2 into valuable chemical compounds. However, the low activity of photocatalysts has hindered their development. By using defective g-C 3 N 4 /CeO 2 heterojunctions, CO 2 was successfully photo-reduced with high performance under ambient water vapor conditions without adding additives. g-C 3 N 4 in this system has a significant impact on CO 2 conversion efficiency, with 5 wt% g-C 3 N 4 /CeO 2 exhibiting competitive performance, achieving 45.66 μmol/g CO in 6 h with nearly 100% selectivity. Photoactivity is attributed to the formation of g-C 3 N 4 /CeO 2 heterojunctions, which provide excellent electron transport and electron-hole separation. Additionally, light enhances the CO 2 adsorption capacity of the catalyst, thereby improving reaction properties. The photogenerated electrons generated under light excitation can quickly gather at the surface and defective parts of the sample, facilitating effective CO 2 adsorption and promoting the formation of *COOH, thus promoting the photoreduction process of CO 2 . Cycle tests also demonstrate long-term stability. Highly efficient charge separation and reduced free energy of CO 2 reduction both promote CO 2 conversion performance. This work can provide an important idea for designing CeO 2 -based CO 2 photocatalysts.