In Situ Constructed Perovskite-Chalcogenide Heterojunction for Photocatalytic CO 2 Reduction.

Perovskite nanocrystals (PNCs) are promising candidates for solar-to-fuel conversions yet exhibit low photocatalytic activities mainly due to serious recombination of photogenerated charge carriers. Constructing heterojunction is regarded as an effective method to promote the separation of charge carriers in PNCs. However, the low interfacial quality and non-directional charge transfer in heterojunction lead to low charge transfer efficiency. Herein, a CsPbBr -CdZnS heterojunction is designed and prepared via an in situ hot-injection method for photocatalytic CO reduction. It is found that the high-quality interface in heterojunction and anisotropic charge transfer of CdZnS nanorods (NRs) enable efficient spatial separation of charge carriers in CsPbBr -CdZnS heterojunction. The CsPbBr -CdZnS heterojunction achieves a higher CO yield (55.8 µmol g  h ) than that of the pristine CsPbBr NCs (13.9 µmol g  h ). Furthermore, spectroscopic experiments and density functional theory (DFT) simulations further confirm that the suppressed recombination of charge carriers and lowered energy barrier for CO reduction contribute to the improved photocatalytic activity of the CsPbBr -CdZnS heterojunction. This work demonstrates a valid method to construct high-quality heterojunction with directional charge transfer for photocatalytic CO reduction. This study is expected to pave a new avenue to design perovskite-chalcogenide heterojunction.