Ultrathin 2D/2D ZnIn2S4/g-C3N4 Nanosheet Heterojunction with Atomic-Level Intimate Interface for Photocatalytic Hydrogen Evolution under Visible Light

Designation of high-efficiency water splitting photocatalyst is still a challenge in converting solar energy into chemical fuels. Heterojunction can inhibit recombination of carriers which is considered to be a reliable strategy to improve photocatalytic performance on water splitting. In this work, a "face-to-face" 2D tight heterostructure is constructed by growing ZnIn2S4 nanosheets on g-C3N4 nanosheets. Due to the ultrathin 2D structure and large amounts of N-S bonds forming at the interface of heterojunction affording charge transferring tunnel, the synthesized 2D heterojunction photocatalysts successfully accelerate the carrier migration rate and decrease recombination probability of photogenerated electrons and holes. As a result, the optimized ZISCN-50 sample has excellent photocatalytic H-2 production activity (10.92 mmol h(-1) g(-1)) under visible light, which is approximate to 5.2 times of ZnIn2S4 (2.09 mmol h(-1) g(-1)) and 136.5 times of pure g-C3N4 nanosheets (0.08 mmol h(-1) g(-1)). Cycle experiments show that the composite material has excellent stability and recyclability. This work provides fresh insights into atomic-level structure and interface design in order to synthesize high-efficiency 2D/2D heterojunction photocatalysts.