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 Bi 3 O 4 Cl and 2D g-C 3 N 4 for photocatalytic CO 2 reduction. The weak vdW interaction enables Bi 3 O 4 Cl/g-C 3 N 4 with desirable moderate bandgap and built-in electronic field, which can efficiently separate the electron-hole pairs. As a result, Bi 3 O 4 Cl/g-C 3 N 4 heterostructures exhibit better photocatalytic CO 2 reduction activity compared with pure Bi 3 O 4 Cl and g-C 3 N 4 . The optimized Bi 3 O 4 Cl/20%g-C 3 N 4 possesses the highest CO 2 conversion efficiency with CO and CH 4 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-C 3 N 4 semiconductors, but also contributes to engineering vdW heterojunctions for satisfactory solar energy conversion performance.