▎ 摘　　要

A magnetically separable ZnFe2O4-graphene nanocomposite photocatalyst with different graphene content was prepared by a facile one-step hydrothermal method. The graphene sheets in this nanocomposite photocatalyst are exfoliated and decorated with ZnFe2O4 nanocrystals. It was found that in the presence of H2O2, the photodegradation rate of methylene blue (MB) was 88% after visible light irradiation for only 5 min and reached up to 99% after irradiation for 90 mm. In comparison with pure ZnFe2O4 catalyst, ZnFe2O4-graphene serves a dual function as the catalyst for photoelectrochemical degradation of MB and the generator of a strong oxidant hydroxyl radical (center dot OH) via photoelectrochemical decomposition of H2O2 under visible light irradiation. ZnFe2O4 nanoparticles themselves have a magnetic property, which makes the ZnFe2O4-graphene composite magnetically separable in a suspension system, and therefore it does not require additional magnetic components as is the usual case.