Lead‐Free Halide Perovskite Cs3Bi2xSb2–2xI9 (x≈ 0.3) Possessing the Photocatalytic Activity for Hydrogen Evolution Comparable to that of (CH3NH3)PbI3. Issue 39 (25th August 2020) - Chen, Guoqiang
Abstract: Lead‐free perovskites Cs3 Bi2 x Sb2–2 x I9 ( 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 (CH3 NH3 )PbI3, Cs3 Bi2 x Sb2–2 x I9 has a better catalytic performance under air mass 1.5 G (AM 1.5 G) simulated sunlight (100 mW cm −2 ), powders of Cs3 Bi0.6 Sb1.4 I9 (100 mg) loaded with Pt nanoparticles show < H2 evolution rate of 92.6 µ mol h −1, which greatly exceeds that of (CH3 NH3 )PbI3 powders loaded with Pt nanoparticles (100 mg catalyst, 4 µ mol h −1 ). The Cs3 Bi2 x Sb2–2 x I9 has a high stability, with no apparent decrease in catalytic activity after five consecutive H2 evolution experiments. The doping of Sb in Cs3 Bi2 x Sb2–2 x I9 effectively reduces the contribution of Bi 3+ on the conduction band, attenuating the effect of Bi vacancy on band structure. Compared with pure Cs3 Bi2 I9 and Cs3 Sb2 I9, Cs3 Bi2 x Sb2–2 x I9 has fewer midgap states and better optical absorption, which greatly enhances its performance for the hydrogen evolution reaction. Abstract : Solid solutions of Cs3 Bi2 I9 and Cs3 Sb2 I9, Cs3 Bi2 x Sb2–2 x I9, are prepared as lead‐free perovskites for the hydrogen evolution reaction (HER). The HER performance of Cs3 Bi0.6 Sb1.4 I9 is comparable to those of the best‐known lead‐based perovskites. There are several reasons why Cs3 Bi0.6 Sb1.4 I9 is far better in the catalytic activities than Cs3 Bi2 I9 or Cs3 Sb2 I9 . Compared with Cs3 Bi2 I9 and Cs3 Sb2 I9, Cs3 Bi0.6 Sb1.4 I9 absorbs more strongly in a wider range of the visible spectrum and has far fewer midgap states.