Lead-Free Halide Perovskite Cs3Bi2xSb2-2xI9(x≈0.3) Possessing the Photocatalytic Activity for Hydrogen Evolution Comparable to that of (CH3NH3)PbI3

Lead-free perovskites Cs3Bi2xSb2-2xI9(x=0.1, 0.3, 0.5, 0.7, 0.9) are prepared by a co-precipitation method and their photocatalytic performance for hydrogen production is studied in aqueous HI solution. Compared with the lead-based perovskite (CH3NH3)PbI3, Cs(3)Bi(2)(x)Sb(2-2)(x)I(9)has a better catalytic performance under air mass 1.5 G (AM 1.5 G) simulated sunlight (100 mW cm(-2)), powders of Cs3Bi0.6Sb1.4I9(100 mg) loaded with Pt nanoparticles show < H(2)evolution rate of 92.6 mu mol h(-1), which greatly exceeds that of (CH3NH3)PbI(3)powders loaded with Pt nanoparticles (100 mg catalyst, 4 mu mol h(-1)). The Cs(3)Bi(2)(x)Sb(2-2)(x)I(9)has a high stability, with no apparent decrease in catalytic activity after five consecutive H(2)evolution experiments. The doping of Sb in Cs(3)Bi(2)(x)Sb(2-2)(x)I(9)effectively reduces the contribution of Bi(3+)on the conduction band, attenuating the effect of Bi vacancy on band structure. Compared with pure Cs(3)Bi(2)I(9)and Cs3Sb2I9, Cs(3)Bi(2)(x)Sb(2-2)(x)I(9)has fewer midgap states and better optical absorption, which greatly enhances its performance for the hydrogen evolution reaction.