Spatially distributed Z-scheme heterojunction of g-C3N4/SnIn4S8 for enhanced photocatalytic hydrogen production and pollutant degradation

[Display omitted] •The in-situ growth of SnIn4S8 nanosheets on tubular g-C3N4 is first reported.•The surface structure regulation for the spatially distributed composite is achieved.•The Z-scheme path with faster charge transfer ensures more reactive species to work.•The products show high activity in RhB degradation, Cr(VI) reduction and H2 evolution. Thanks to the large specific surface area of its spatial structure, tubular graphitic carbon nitride (g-C3N4) is frequently accepted as a powerful substrate for designing composite materials to suppress the agglomeration of surface grown species. In this work, a spatially distributed Z-scheme heterojunction is successfully established through in situ growth of SnIn4S8 (SIS) nanosheets on g-C3N4 microtubes (T-CN) for the first time. Experimental results demonstrate that a fast charge transfer channel can be built by a solid–solid contact interface, and more abundant reactive sites can be exposed due to the construction of T-CN/SIS heterojunction. Photocatalytic assessments reveal that the optimal T-CN/SIS sample can achieve the significant rate constants of 0.092 min−1 and 0.068 min−1 for Rhodamine B (RhB) degradation and hexavalent chromium (Cr(VI)) reduction, which are approximately 7.1 and 17.0 times higher than bare g-C3N4, respectively. Furthermore, it also displays a remarkable average hydrogen evolution rate up to 2411.9 μmol g−1 h−1, about 3.6 times higher than pristine g-C3N4. In addition to the high photocatalytic activity, the sample exhibits an outstanding stability in all these photocatalytic reactions. Therefore, it should be expected that this work would provide a guiding strategy for construction of g-C3N4-based composites.