Anions‐Exchange‐Induced Efficient Carrier Transport at CsPbBr x Cl 3‐x /TiO 2 Interface for Photocatalytic Activation of C(sp 3 )−H bond in Toluene Oxidation

Inspired by the unique band structure of CsPbBr 3 , we have developed an asymmetric Cl‐exchange strategy based on the CsPbBr x Cl 3‐x /TiO 2 heterojunction‐type catalyst and achieved photocatalytic activation of C(sp 3 )−H bond using the toluene oxidation reaction as a proof‐of‐concept application. The anion exchange at the supported CsPbBr 3 surface results in the CsPbBr x Cl 3‐x /TiO 2 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 CsPbBr 3 nanocrystals). The remarkable photocatalytic performance can be ascribed to the improved carrier transport at CsPbBr x Cl 3‐x /TiO 2 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(sp 3 )−H bond.