In Situ Grown Monolayer N-Doped Graphene on CdS Hollow Spheres with Seamless Contact for Photocatalytic CO2 Reduction

Photocatalytic CO2 reduction is an effective way to simultaneously mitigate the greenhouse effect and the energy crisis. Herein, CdS hollow spheres, on which monolayer nitrogen-doped graphene is in situ grown by chemical vapor deposition, are applied for realizing effective photocatalytic CO2 reduction. The constructed photocatalyst possesses a hollow interior for strengthening light absorption, a thin shell for shortening the electron migration distance, tight adhesion for facilitating separation and transfer of carriers, and a monolayer nitrogen-doped graphene surface for adsorbing and activating CO2 molecules. Achieving seamless contact between a photocatalyst and a cocatalyst, which provides a pollution-free and large-area transport interface for carriers, is an effective strategy for improving the photocatalytic CO2 reduction performance. Therefore, the yield of CO and CH4, as dominating products, can be increased by four and five times than that of pristine CdS hollow spheres, respectively. This work emphasizes the importance of contact interface regulation between the photocatalyst and the cocatalyst and provides new ideas for the seamless and large-area contact of heterojunctions.