Van der Waals heterojunction for selective visible-light-driven photocatalytic CO2 reduction

• Carbon nitride coupled Bi 9 O 7.5 S 6 nanoplates were fabricated as a Van der Waals heterojunction. • Van der Waals heterojunction accelerated the separation and migration of photogenerated carriers. • The Van der Waals heterojunction revealed enhanced photocatalytic activity for CO 2 reduction. • The photocatalytic mechanism was unveiled based on the experiments and DFT calculations. The product selectivity and efficiency of photocatalytic CO 2 reduction are often restricted by the multi-electron transfer and reactive centers in the artificial photosynthetic system. To overcome these limitations, in this work, atomically thin carbon nitride (CN) coupled Bi 9 O 7.5 S 6 (BOS) nanoplates were fabricated as a two-dimensional/two-dimensional (2D/2D) Van der Waals (VDW) heterojunction for CO 2 photoreduction. Our experimental and density functional theory (DFT) calculations showed that the CO* could be adsorbed more strongly on BOS than CN, which could be further hydrogenated before desorption, explaining the observation why the main products of photocatalytic CO 2 reduction on BOS was CH 4 and CH 3 OH. Benefiting from the 2D/2D VDW heterojunction, 20CN/BOS revealed a CO generation rate of 37.2 μmol g catalyst −1 under visible light irradiation, roughly 14.9-fold and 1.4-fold higher than that of BOS and CN alone. Our work paves a way to design new VDW hetero-structured photocatalysts for CO 2 reduction to valuable products.