Rational design and construction of novel hierarchical Au/BPNSs/ZnIn2S4 heterojunction photocatalyst for enhancing photocatalytic H2 production under visible light

A novel hierarchical Au/black phosphorus nanosheets/ZnIn2S4 (Au/BPNSs/ZIS) heterojunction photocatalyst has been successfully synthesized in this work, in which ZnIn2S4 (ZIS) nanosheets were first grown in situ on black phosphorus nanosheets (BPNSs) using the solvothermal method. Au nanoparticles were then photo-deposited on the outer surface of the ZIS. The hydrogen evolution rate of the optimal Au/BPNSs/ZIS is 1674 μmol·h−1·g−1, which is 5 and 17 times higher than that of pure ZIS and few-layer BPNSs, respectively. The photocatalyst of BPNSs/ZIS is primarily attributed to the formation of Zn-P bonds between them to stabilize the connection of BPNSs/ZIS heterojunctions, according to X-ray photoelectron spectroscopy (XPS). At the same time, the work function calculation reveals that the interface electric field formed from ZIS to BPNSs is the driving force of interface charge transfer, allowing photoexcited electrons to migrate directionally on the interface and improve hydrogen evolution efficiency under visible light irradiation. Furthermore, Au nanoparticles are photo-deposited on the ZIS surface to form Schottky junctions, which improves photocatalytic performance even further. This work offers a novel approach to developing BP-based heterojunctions in photocatalysis.