Hierarchical NiCo2S4/ZnIn2S4 heterostructured prisms: High-efficient photocatalysts for hydrogen production under visible-light

Exploring low-cost co-catalyst to ameliorate the photocatalytic activity of semiconductors sets a clear direction for solving energy crisis and achieving efficient solar-chemical energy conversion. In this work, a unique hierarchical hollow heterojunction was constructed by in-situ growing ZnIn2S4 nanosheets on the porous NiCo2S4 hollow prisms through a low temperature solvothermal method, in which NiCo2S4 with semi-metal property acted as non-noble metal co-catalyst. NiCo2S4 co-catalyst was innovatively encapsulated in ZnIn2S4, which not only relieved the light shielding effect caused by the large loading amount of co-catalyst, but also supplied abundant active sites for H2 evolution. The hierarchical hollow heterostructure of NiCo2S4/ZnIn2S4 provided a highly efficient channel for charge transfer. Combining these advantages, NiCo2S4/ZnIn2S4 composite demonstrated excellent photocatalytic activity. In the absence of sacrificial agent, the NiCo2S4/ZnIn2S4 photocatalyst achieved a remarkable improved H2 yield of 0.77 mmol g-1h-1 under visible light irradiation (k > 400 nm), which is 6.6 times greater than that of ZnIn2S4. Besides, NiCo2S4 even exhibited better performance on the H2 evolution improvement of ZnIn2S4 than precious metal Pt. This work will offer novel insights into the reasonable design of non-noble metal photocatalysts with respectable activity for water splitting.