Synergistic surface activation during photocatalysis on perovskite derivative sites in heterojunction

Halide perovskites and derivatives have been used as emerging photocatalysts due to their unique optoelectronic and structural diversity. However, compared with the well-explored photophysical processes for light-driven more energetic carriers to trigger redox reactions, catalytic effects on the surface of halide perovskite or their derivatives for chemical transformations between reactive species are seldom addressed, which is equally important for improving the efficiency for halide perovskite-based photocatalysts. Here, we demonstrate that Cs 3 Bi 2 Br 9 sites in the Cs 3 Bi 2 Br 9 /CdS heterojunction, not only participate in light-driven processes, but also play a vital role for the activation and conversion of key intermediates during C(sp 3 )-H bond transformation, via a more thermodynamically and kinetically favorable surface reaction pathway. Besides, various aromatic hydrocarbons can be effectively photocatalytic converted to corresponding aldehydes/ketones as major products. This work highlights the importance of surface catalysis mechanism in photocatalysis not only for halide perovskites but also for other semiconductors.