Revealing the A-site effect of lead-free A3Sb2Br9 perovskite in photocatalytic C (sp3)-H bonds activation.

Lead-free halide perovskite of A 3 Sb 2 Br 9 is utilized as photocatalyst for the first time to C (sp 3 )-H bonds activation. A 3 Sb 2 Br 9 nanoparticles (A 3 Sb 2 Br 9 NPs) with different ratios of Cs and MA show different photocatalytic activity for toluene oxidation and the photocatalytic performance is enhanced when increasing the amount of Cs. We reveal that the octahedron distortion caused by A-site cations can change the electronic property of X-site ions and further affect the electron transfer from toluene molecules to Br sites. After the regulation of A-site cations, the photocatalytic activity is higher with A 3 Sb 2 Br 9 NPs than that with some classic photocatalysts (TiO 2 , WO 3 and CdS). The main active species involved in photocatalytic oxidation of toluene are photogenerated holes (h + ) and superoxide anions ( •O 2 - ). The view of octahedron distortion by A-site cations affecting photocatalytic activity remains unique and is also a step forward for understanding more insights to halide-perovskite-based photocatalysis. This opinion of relations between octahedron distortion and photocatalysis can also guide the design of new photocatalytic systems involved in other halide perovskites.