Three-Dimensional Multihierarchical Hexagonal/Cubic ZnIn₂S₄ S-Scheme Heterophase Junction for Superior Photocatalysis

It is an important strategy to design composite materials with a special microstructure and a tunable electronic structure through structural compatibility. In this work, a novel hexagonal/cubic ZnIn₂S₄ polymorphic heterophase junction with a three-dimensional multihierarchical structure is successfully constructed by in situ growth of hexagonal ZnIn₂S₄ nanosheets on the surface of cubic ZnIn₂S₄ flower-like microspheres prepared by topological chemical synthesis. On the one hand, the multihierarchical architecture provides large specific surface area, abundant active sites, and excellent light trapping capability. On the other hand, the construction of a direct S-scheme heterophase junction enables the formation of a special charge-transfer channel under the force of a built-in electric field, which not only improves the separation efficiency of carriers but also ensures the stronger reaction activity of charges. The prepared ZnIn₂S₄ heterophase junction composite photocatalyst exhibits greatly boosted photocatalytic efficiency in rhodamine B degradation, hexavalent chromium reduction, and water splitting for hydrogen production, which are 12.3, 6.5, and 3.1 times higher than that of pure hexagonal ZnIn₂S₄ and 8.1, 5.1, and 2.3 times higher than that of pure cubic ZnIn₂S₄, respectively, demonstrating its significant potential for applications in energy and environmental fields.