3D porous Cu-NPs/g-C3N4 Foam with Excellent CO2 Adsorption and Schottky Junction Effect for Photocatalytic CO2 Reduction

Abstract This study exhibits a remarkable enhancement in photocatalytic reduction of CO2 through the construction of a 0D/3D composite photocatalyst of Cu-NPs/g-C3N4 foam (Cu/CF) in a heterogeneous system. The Cu/CF composite is obtained by ingeniously loading Cu-NPs on a featured g-C3N4 foam combining the template method and microwave method. Here, the well-defined Cu/CF composite photocatalyst exhibits excellent performance of CO2 adsorption and diffusion due to its three-dimensional micron-scale pores, and the CO2 adsorption amount of composite photocatalyst reaches 0.179 mmol/g at 1.00 bar and 273.15 K, which is about 2.63 times than that of pure g-C3N4 powder. Simultaneously, the formation of nano-scale Schottky barrier between g-C3N4 and Cu-NPs can accumulate photo-generated electrons on the surface of Cu-NPs, consequently suppressing the recombination of photo-generated e--h+. The Cu/CF composite photocatalyst demonstrates a fabulous photocatalytic activity for CO production with a yield of 10.247 µmol·g-1·h-1, 2.56 and 6.34 times over that of pure g-C3N4 foam and g-C3N4 powder. The notable advancement of photocatalytic efficiency can be attributed to superior improvement of CO2 adsorption and charge separation efficiency. Our strategy can supply an exploratory platform to comprehend the significance of engineering at different scales in a heterogeneous system.