Efficient photocatalytic toluene selective oxidation over Cs3Bi1.8Sb0.2Br9 Nanosheets: Enhanced charge carriers generation and C–H bond dissociation

Inert C–H bonds activation at room temperature has been regarded as the control step in photocatalytic generation of valuable products from hydrocarbons. Herein, lead-free perovskite Cs3Bi1.8Sb0.2Br9 nanosheets with a proper amount of Sb in Cs3Bi2Br9 not only improves optical absorption due to anomalous band gap behavior, but also promotes the generation of holes (h+). The convergence of h+ on the surface of Cs3Bi1.8Sb0.2Br9 is crucial for the dissociation of toluene C(sp3)–H bond, which was proved by the density functional theory calculation and isotopic labelling results. The excellent activity in photocatalytic selective oxidation of toluene with a conversion rate of 5.83 mmol g−1h−1 under visible light is the highest ever achieved. This work sheds light on the modification of halide perovskites through the regulation of B-site cations for photocatalytic applications.