Realizing efficient CO2 photoreduction in Bi3O4Cl: Constructing van der Waals heterostructure with g-C3N4

The van der Waals (vdW) heterojunction formed between two-dimensional materials can break the anisotropy of the electron beam and is an effective method to improve the photocatalytic performance. Herein, vdW heterostructure is successfully constructed between layered Bi3O4Cl and 2D g-C3N4 for photocatalytic CO2 reduction. The weak vdW interaction enables Bi3O4Cl/g-C3N4 with desirable moderate bandgap and built-in electronic field, which can efficiently separate the electron-hole pairs. As a result, Bi3O4Cl/g-C3N4 heterostructures exhibit better photocatalytic CO2 reduction activity compared with pure Bi3O4Cl and g-C3N4. The optimized Bi3O4Cl/20%g-C3N4 possesses the highest CO2 conversion efficiency with CO and CH4 generation rate of 6.6 and 1.9 μmol g−1 h−1, respectively. This work not only reports an effective reference for vdW heterojunction system based on Bi-based and g-C3N4 semiconductors, but also contributes to engineering vdW heterojunctions for satisfactory solar energy conversion performance.