Z-Scheme ZnIn2S4 Nanosheets/Reduced Graphene Oxide/Nb2O5 Nanoplates Heterojunction for Photocatalytic Hydrogen Production

Abstract Photocatalytic hydrogen production represents a promising strategy for the sustainable conversion of solar energy into chemical fuels, yet its efficiency is often limited by rapid charge recombination and narrow light absorption. To address these challenges, an all-solid-state Z-scheme ZnIn2S4/reduced graphene oxide/Nb2O5 (ZIS/rGO/NO) heterojunction was constructed via hydrothermal method. In this hierarchical structure, two-dimensional rGO serves as an efficient electron-transfer bridge between ZIS nanosheets and NO nanoplates, facilitating rapid charge separation and migration while suppressing electron−hole recombination. The optimized ZIS/rGO/NO photocatalyst achieves a remarkable hydrogen evolution rate of 5.2 mmol·g−1·h−1 under visible-light irradiation. The resulting hydrogen evolution rate is 8.7 and 3.5 times greater than that of pure ZIS and the binary ZIS/NO composite, respectively. Furthermore, an apparent quantum efficiency (AQE) of 15.3% was achieved at 420 nm. The synergistic interplay between the Z-scheme heterojunction and graphene mediator offers an effective strategy for designing highly active and stable photocatalysts for solar energy conversion.