In situ construction of core-shell NiFe-LDH@ZnIn2S4 direct Z-scheme heterojunction for facilitating photocatalytic H2 evolution

Abstract

The development of photocatalysts with non-noble metals and the effective separation of photoexcited carriers is a significant strategy for accelerating surface reaction kinetics and promoting water splitting to produce H2. Herein, an exquisite core-shell NiFe-LDH@ZnIn2S4 heterojunction photocatalyst was constructed by in situ decoration of ultrathin ZnIn2S4 nanosheets on the surface of the flower-like NiFe-LDH microsphere. The synthesized 3D hierarchical NiFe@ZIS-25 composite exhibits enhanced photocatalytic H2 evolution activity, reaching 9.12 mmol·h-1·g-1, which is 2.52-fold higher than pure ZnIn2S4. The significant improvement in H2 evolution performance could be attributed to the hierarchical core-shell structure of the NiFe@ZIS-25 photocatalyst, which enhanced the light capture ability. In addition, the interfacial coupling effect of ZnIn2S4 and NiFe-LDH is beneficial to the migration of carriers. More importantly, the construction of Z-scheme heterojunction efficiently promotes the fast translation of photogenerated carriers while preserving a stronger reduction potential to achieve H2 evolution. This work elucidates a rational strategy to develop efficient photocatalysts with hierarchical core-shell structures for water splitting.