Heterojunction‐Type Photocatalytic System Based on Inorganic Halide Perovskite CsPbBr3†

Summary of main observation and conclusion The heterojunction‐type structure has shown significant merits in tuning the optical properties and carrier physics. Inspired by the excellent absorption capability of halide perovskite materials for visible light, a series of CsPbBr 3 /TiO 2 heterojunction‐type photocatalysts with various all‐inorganic‐perovskite/TiO 2 ratios are successfully fabricated by the ligand‐assisted reprecipitation (LARP) method. The heterojunction structure extends the light absorption of TiO 2 with good chemical and structural stability. A Pb‐O interaction at the CsPbBr 3 /TiO 2 interface is observed by the XPS and confirmed by the TRPL showing improved interface carrier transport and stability. The heterojunction‐type catalyst shows drastically enhanced photocatalytic activity towards the direct oxidation of toluene with O 2 molecule, as an important reaction for organic chemical synthesis. The optimized sample shows an activity of 2356 μmol·g –1 ·h –1 at 75 °C, 4 times of that of the naked CsPbBr 3 nanocrystals, and 3 times of that of the bare TiO 2 . Based on the investigation with trapping agents, a reaction mechanism is hence proposed suggesting that the photo‐generated hole may be involved in the rate‐limiting step. This work demonstrates the potential of inorganic halide perovskite‐based heterojunction structure for photocatalytic applications.