Constructing a Cs3Sb2Br9/g‐C3N4 Hybrid for Photocatalytic Aromatic C(sp3)H Bond Activation

Utilizing halide perovskites for photocatalytic aromatic C( sp 3 )H bond activation remains a great challenge due to the serious recombination of photogenerated charge carriers and slow reaction dynamics of the materials themselves. Herein, a lead‐free perovskite‐based hybrid of Cs 3 Sb 2 Br 9 /g‐C 3 N 4 nanosheet is constructed and applied for photocatalytic aromatic C( sp 3 )H bond activation, which shows enhanced photocatalytic performance. By introducing ultrathin g‐C 3 N 4 nanosheets as the heterogeneous nucleation sites, size‐reduced and well‐dispersed Cs 3 Sb 2 Br 9 nanocrystals can be obtained. The as‐formed close contact and high‐quality heterointerface between Cs 3 Sb 2 Br 9 and g‐C 3 N 4 provides pathways for fast charge transfer which is beneficial to improve the separation efficiency of photogenerated electron−hole pairs. Under visible light irradiation, the Cs 3 Sb 2 Br 9 /g‐C 3 N 4 hybrid photocatalyst can effectively oxidize toluene toward benzaldehyde and benzyl alcohol with a total conversion rate of 8346.8 μmol g −1 h −1 , which is 26.6‐ and 6.0‐fold that of pure g‐C 3 N 4 and Cs 3 Sb 2 Br 9 , respectively. This work demonstrates the potential of all‐inorganic lead‐free halide perovskite‐based heterostructures for photocatalytic organic reactions.