Construction of core-shell g-C3N4@ZnIn2S4 hierarchical hollow heterostructure for enhanced photocatalytic activity under visible light irradiation

Hierarchical hollow heterostructures with ultrathin two-dimensional (2D) nanosheet subunits have various intrinsic advantages in photocatalytic aspects such as increasing light collection, accelerating electron hole separation and migration, and promoting surface redox reactions. Herein, we demonstrated the rational design and construction of hierarchical hollow core-shell g-C3N4@ZnIn2S4 heterostructures with coating the ZnIn2S4 nanosheets on the hollow g-C3N4 spheres by a low temperature solvothermal route. The hollow g-C3N4@ZnIn2S4 spherical nanoflower realized the improvement of photocatalytic activity by multiple scattering and reflection of light in the spherical cavity. Furthermore, the photo-generated charge carriers can be effectively separated by constructing layered heterojunctions. The optimized g-C3N4@ZnIn2S4 exhibited the outstanding photocatalytic performance (nearly 84% degradation of tetracycline within 60 min visible light irradiation) as well as excellent cyclical stability. In addition, the total organic carbon removal (TOC) rate of the optimal g-C3N4@ZnIn2S4 composite photocatalyst can be reached up to 64%. Meanwhile, the possible degradation intermediates and degradation paths were analyzed by liquid chromatograph-mass spectrometer (LC-MS) test results. This work provides a feasible design idea of constructing the core-shell hierarchical hollow heterostructure photocatalyst with high photocatalytic performance.