A novel hydrangea-like ZnIn2S4/FePO4 S-scheme heterojunction via internal electric field for boosted photocatalytic H2 evolution

Reasonable design of high-performance catalysts with heterojunction to suppress the combination of electron-hole pairs has become an appealing challenge in photocatalytic field. Herein, a novel hydrangea-like ZnIn2S4/FePO4 with S-scheme heterojunction was constructed via an ultrasound-annealing process for photocatalytic H2 evolution. The composites showed remarkable photocatalytic H2 production performance (3.337 mmol h−1 g−1), which was approximately 7.5 times higher than that of blank ZnIn2S4 (0.446 mmol h−1 g−1). The improved photocatalytic H2 evolution was mainly ascribed to the accelerated electron-hole separation through the construction of S-scheme heterojunction in interface. Moreover, the hydrangea-like structure provided abundant active sites and huge specific surface area, which was conducive to the exceptional photocatalytic activity. Simultaneously, both experimental and Density Functional Theoretical calculation results provided strong evidence for the transfer path of photogenerated carriers following the S-scheme heterojunction, and the unique mechanism of photocatalytic H2 production was proposed. In addition, the hydrangea-like ZnIn2S4/FePO4 heterojunction photocatalyst showed a commendable stability with no distinct decrease after three cycle tests, demonstrating its potential as a recoverable photocatalyst. This work offered insights into the design and preparation of highly efficient photocatalysts with S-scheme heterojunction.