Preparation of Heterojunctions Based on Cs(3)Bi(2)Br(9) Nanocrystals and g-C(3)N(4) Nanosheets for Photocatalytic Hydrogen Evolution

Heterojunctions based on metal halide perovskites (MHPs) are promising systems for the photocatalytic hydrogen evolution reaction (HER). In this work, we coupled Cs(3)Bi(2)Br(9) nanocrystals (NCs), obtained by wet ball milling synthesis, with g-C(3)N(4) nanosheets (NSs), produced by thermal oxidation of bulk g-C(3)N(4,) in air. These methods are reproducible, inexpensive and easy to scale up. Heterojunctions with different loadings of Cs(3)Bi(2)Br(9) NCs were fully characterised and tested for the HER. A relevant improvement of H(2) production with respect to pristine carbon nitride was achieved at low NCs levels reaching values up to about 4600 µmol g(−1) h(−1). This work aims to provide insights into the synthesis of inexpensive and high-performing heterojunctions using MHP for photocatalytic applications.