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

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.