摘要： In this work, Ag/Fe3O4/SnO2 composites with two types of graphene (Ag/Fe3O4/SnO2/NGP and Ag/Fe3O4/SnO2/graphene) were synthesized using co-precipitation and applied in degradation of methylene blue (MB) as a target pollutant in a solution. The prepared sample was characterized using X-ray diffraction (XRD), thermogravimetric analysis (TGA) and UV-Vis spectroscopy. TGA characterization indicated that two types of graphene were successfully loaded into the Ag/Fe3O4/SnO2 composites. The experiments were performed at a pH of 13 and an initial of MB concentration of 20 mg/L. Among the two types of graphene, the Ag/Fe3O4/SnO2/graphene shows the highest photocatalytic activity for degradation of MB under UV light irradiation, and the photocatalytic performance decreases in the order Ag/Fe3O4/SnO2/NGP > Ag/Fe3O4/SnO2 > Fe3O4/SnO2. The optimum conditions for irradiation time and catalyst dosages were 120 min and 0.3 g/L, respectively. The addition of diammonium oxalate, which acts as a hole scavenger, leads to a simultaneous decrease in the dye degradation. This suggests that hole is the dominant active species responsible for the dye degradation. The reusability tests have also been carried out to ensure the stability of the used catalysts.