Preparation of Heterojunctions Based on Cs3Bi2Br9 Nanocrystals and g-C3N4 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 Cs3Bi2Br9 nanocrystals (NCs), obtained by wet ball milling synthesis, with g-C3N4 nanosheets (NSs), produced by thermal oxidation of bulk g-C3N4, in air. These methods are reproducible, inexpensive and easy to scale up. Heterojunctions with different loadings of Cs3Bi2Br9 NCs were fully characterised and tested for the HER. A relevant improvement of H2 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.