Nanoscale Janus Z‐Scheme Heterojunction for Boosting Artificial Photosynthesis

Abstract Artificial photosynthesis for CO 2 reduction coupled with water oxidation currently suffers from low efficiency due to inadequate interfacial charge separation of conventional Z‐scheme heterojunctions. Herein, an unprecedented nanoscale Janus Z‐scheme heterojunction of CsPbBr 3 /TiO x is constructed for photocatalytic CO 2 reduction. Benefitting from the short carrier transport distance and direct contact interface, CsPbBr 3 /TiO x exhibits significantly accelerated interfacial charge transfer between CsPbBr 3 and TiO x (8.90 × 10 8 s −1 ) compared with CsPbBr 3 :TiO x counterpart (4.87 × 10 7 s− 1 ) prepared by traditional electrostatic self‐assembling. The electron consumption rate of cobalt doped CsPbBr 3 /TiO x can reach as high as 405.2 ± 5.6 µmol g −1 h −1 for photocatalytic CO 2 reduction to CO coupled with H 2 O oxidation to O 2 under AM1.5 sunlight (100 mW cm −2 ), over 11‐fold higher than that of CsPbBr 3 :TiO x , and surpassing the reported halide‐perovskite‐based photocatalysts under similar conditions. This work provides a novel strategy to boost charge transfer of photocatalysts for enhancing the performance of artificial photosynthesis.