Environmentally Stable Mesoporous g-C3N4 Modified Lead-Free Double Perovskite Cs2AgBiBr6 for Highly Efficient Photocatalytic Hydrogen Evolution

Lead halide perovskites have received attention in the field of photocatalytic hydrogenation due to its excellent light absorbing capacity and suitable conduction band position. However, lead toxicity is huge to the environment and human damage, which constrains its large-scale practical application. In this work, we rationally design a series of lead-free Cs2AgBiBr6 perovskites modified with a mesoporous g-C3N4 and demonstrate their highly efficient and stable hydrogen evolution performances under visible-light irradiation. Spectroscopy analysis illustrates the formation of type II heterojunction structure between Cs2AgBiBr6 and g-C3N4. The best g-C3N4/Cs2AgBiBr6-10 exhibits the excellent photocatalytic hydrogenation rate of 60 μmol g−1 h−1 without using any precious metals as promoters, which is superior to original Cs2AgBiBr6 and pristine g-C3N4. Furthermore, the observed photocatalytic performances are well maintained when they are directly exposed to the ambient environment for 40 days, indicating the excellent environmental stability and photocatalytic recyclability. This study offers a new opportunity for the design of air-stable and lead-free perovskite Cs2AgBiBr6 based photocatalysts for hydrogen evolution.Graphical Abstract