Nanoscale Janus Z-Scheme Heterojunction for Boosting Artificial Photosynthesis

Artificial photosynthesis for CO₂ 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 CsPbBr₃/TiO_x is constructed for photocatalytic CO₂ reduction. Benefitting from the short carrier transport distance and direct contact interface, CsPbBr₃/TiO_x exhibits significantly accelerated interfacial charge transfer between CsPbBr₃ and TiO_x (8.90 × 10⁸ s⁻¹) compared with CsPbBr₃:TiO_x counterpart (4.87 × 10⁷ s−¹) prepared by traditional electrostatic self-assembling. The electron consumption rate of cobalt doped CsPbBr₃/TiO_x can reach as high as 405.2 ± 5.6 µmol g⁻¹ h⁻¹ for photocatalytic CO₂ reduction to CO coupled with H₂O oxidation to O₂ under AM1.5 sunlight (100 mW cm⁻²), over 11-fold higher than that of CsPbBr₃: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.