▎ 摘　　要

Titanium dioxide mediated semiconductor, nickel sulfide (NiS2) doped graphene photocatalysts were prepared by simple hydrothermal method for the treatment of dye contaminated aqueous solutions. The characterizations of synthesized composites were studied by X-ray diffraction, scanning electron microscope, transmission electron microscope and energy dispersive X-ray. The as-synthesized NiS2-graphene/TiO2 composites promptly removed methylene blue dye under visible light irradiation, exhibiting high photocatalytic efficiency. For the purpose of comparison, the photocatalytic effect of NiS2-graphene composite was also analyzed. The photodegradation of methylene blue was evaluated by the steady decline in the concentration of the dye with increasing time. The rates of the photocatalytic reactions were analyzed giving an insight about the efficiency of each composite.