Synthesis and characterization of P-doped g-C3N4 nanosheet hybridized ZnS nanospheres with enhanced visible-light photocatalytic activity

Phosphorus-doped g-C3N4/ZnS (PCN/ZnS) composite photocatalyst was prepared by element doping and structuring heterojunction by solvothermal methods. The heterojunction composite was characterized by XRD, SEM/TEM, XPS and UV–vis DRS. The photocatalytic properties of PCN, ZnS and PCN/ZnS were studied by photodegradation of tetracycline (TC) with visible light irradiation. The 15%PCN/ZnS showed the highest photocatalytic degradation performance of TC with the reaction rate constant of 0.0529 min−1, which was 40.7 times of ZnS and 6.3 times of PCN. Superoxide radicals and holes played a major role in the photocatalytic degradation process, but not hydroxyl radicals. Besides, according to the conduction and entrainment positions of PCN and ZnS, they form a type II heterojunction structure, which could extend the range of light response, enhance the charges transfer and efficient separation. In general, the design and synthesis of PCN/ZnS provide a new way to photodegrade pharmaceutical wastewater with enhanced photocatalytic properties.