Fabrication of CuS-modified inverse opal g-C3N4 photocatalyst with enhanced performance of photocatalytic reduction of CO2

• A new type of CuS-loaded inverse opal g-C 3 N 4 photocatalyst was fabricated. • The prepared composites showed better performance of photocatalytic reduction of CO 2 . • The optimal CuS loading was 2 wt%, and the corresponding CO production rate was 13.24 μmol g −1 h −1 , which was 3.2 times that of IO CN and 5 times that of Bulk CN. • The direct photo-induced interfacial charge transfer mechanism is proposed to explain the photogenerated electron transfer path. • The improvement of performance is mainly attributed to the combination of inverse opal structure and CuS as cocatalyst. As a greenhouse gas, CO 2 is also a rich carbon resource. Using sunlight to reduce CO 2 to usable substances through photocatalysis can alleviate the greenhouse effect and realize energy recycling. Herein, CuS nanoparticles are grown in situ on the surface of inverse opal g-C 3 N 4 by a one-step hydrothermal method. The inverse opal structure can increase the specific surface area of the material, and CuS can be used as the cocatalyst to accept photo-generated electrons on the conduction band of g-C 3 N 4 , thereby promoting the separation and transfer of photo-generated charges. And the interfacial charge transfer mechanism of CuS further improves the separation efficiency of photogenerated electrons and holes. The photocatalytic reduction of CO 2 activity of the prepared catalyst is greatly improved. The CO yield reaches 13.24 μmol g −1 h −1 . A new strategy is provided to develop artificial photosynthesis for reduction of CO 2 .