Two-dimensional black phosphorus-modified Cs2AgBiBr6 with efficient charge separation for enhanced visible-light photocatalytic H2 evolution

Abstract

Lead-free double halide perovskite (Cs₂AgBiBr₆) is considered to be a potential candidate material for photocatalytic hydrogen production due to its excellent visible light capture capability. However, the rate of the hydrogen evolution reaction (HER) taking into account these catalysts is still insufficient. In this study, two-dimensional black phosphorus (BP) anchored on Cs₂AgBiBr₆ (CABB) by electrostatic coupling was prepared. The resulting catalyst BP/CABB was quite stable in a HBr solution during the entire light reaction and reached a hydrogen production rate of 104.6 μmol h⁻¹ g⁻¹ under visible light, which was higher than that of CABB alone. Significantly enhanced HER activity was explored by optical/photochemical measurements, indicating that BP can be used as an electronic accelerator, transmitted by a Z-scheme heterojunction in the interface of the catalyst to transfer electrons, and further produce hydrogen. This has been instrumental in the high-efficiency photocatalyst by anchoring the nonmetallic active sites on CABB.