In-situ preparation of BiOBr/Bi-doped CsPbBr3 S-scheme heterojunction for efficient photocatalytic CO2 reduction

Metal halide perovskite nanocrystals have garnered significant attention in the realm of photocatalytic CO 2 reduction in recent years owing to their remarkable reducing properties and high selectivity. However, the issue of low photocatalytic activity due to severe carrier recombination phenomena in perovskite has posed a significant challenge. To address this, a one-pot in-situ preparation strategy was employed to create a BiOBr/Bi-doped perovskite nanocrystal S-scheme heterojunction, resulting in a significant improvement in the CO 2 photoreduction performance. The heterojunction material exhibited a CO yield of 151.56 μmolg -1 h −1 , with a selectivity for CO of 93.6 %. The molar ratio of the components was modulated using an in-situ water aging strategy, yielding a photocatalyst performance that exceeded that of pure BiOBr. The synthesis strategy of one-step in-situ preparation of heterojunctions overcomes the problem of insufficient bonding caused by two-step methods. And various characterizations and DFT calculations strongly support the S-scheme mechanism of the photocatalyst. The active site effectively reduces the energy barrier for the transition from *COOH to *CO intermediate, thereby significantly improving photocatalytic activity.