Anions‐Exchange‐Induced Efficient Carrier Transport at CsPbBrxCl3‐x/TiO2 Interface for Photocatalytic Activation of C(sp3)−H bond in Toluene Oxidation

Inspired by the unique band structure of CsPbBr3, we have developed an asymmetric Cl‐exchange strategy based on the CsPbBrxCl3‐x/TiO2 heterojunction‐type catalyst and achieved photocatalytic activation of C(sp3)−H bond using the toluene oxidation reaction as a proof‐of‐concept application. The anion exchange at the supported CsPbBr3 surface results in the CsPbBrxCl3‐x/TiO2 structure with an asymmetric distribution of halide. The resultant heterojunction‐type catalysts exhibit significantly improved photocatalytic activity for toluene oxidation reaction with the highest benzaldehyde production rate at 1874 μmol g−1 h−1 (∼4 times that of the naked CsPbBr3 nanocrystals). The remarkable photocatalytic performance can be ascribed to the improved carrier transport at CsPbBrxCl3‐x/TiO2 interface enabled by the unique band structure due to the asymmetric halide distribution, verified by the micro‐strain discovered through the X‐ray diffraction. This work demonstrates a new pathway to fabricate highly‐efficient halide perovskite heterojunction‐type catalysts for photocatalytic activation of C(sp3)−H bond. Photocatalysis: The CsPbBrxCl3‐x/TiO2 heterojunction‐type catalysts with asymmetric Cl− distribution in CsPbBrxCl3‐x exhibit significantly improved photocatalytic activity for toluene oxidation reaction with the optimized benzaldehyde production rate at 1874 μmol g−1 h−1 (4 times that of the naked CsPbBr3 nanocrystals).