Composite of lead-free halide perovskite Cs3Bi2Br9 with TiO2 as an efficient photocatalyst for C(sp3)−H bond activation

Herein, a facile anti-solvent preparation strategy is proposed to fabricate lead-free halide perovskite Cs 3 Bi 2 Br 9 with TiO 2 , which boosts photocatalytic activation of C(sp 3 )−H bonds in toluene oxidation . TiO 2 not only works as nucleation center to reduce the particle size of perovskite, but could form type II heterojunction with Cs 3 Bi 2 Br 9 , thus improving the photocatalytic performance of the TiO 2 /Cs 3 Bi 2 Br 9 composite. Under AM 1.5 G simulated sunlight irradiation, the optimal TiO 2 /Cs 3 Bi 2 Br 9 composite exhibits both high production rate (9692.5 μmol g −1 h −1 ) and selectivity (91 %) of benzaldehyde product. As verified by in-situ ESR, in-situ FT-IR and DFT calculations, •O 2 − and h + are demonstrated to be the main active species in this process. This work provides a new insight into the design of high-performance lead-free perovskite photocatalysts for organic synthesis.