Facile synthesis of magnetic ZnFe_2O_4-reduced graphene oxide hybrid and its photo-Fenton-like behavior under visible iradiation

摘要

A magnetic ZnFe_2O_4-reduced graphene oxide (rGO) hybrid was successfully developed as a heterogeneous catalyst for photo-Fenton-like decolorization of various dyes using peroxymonosulfate (PMS) as an oxidant under visible light irradiation. Through an in situ chemical deposition and reduction, ZnFe_2O_4 nanoparticles (NPs) with an average size of 23.7 nm were anchored uniformly on rGO sheets to form a ZnFe_2O_4-rGO hybrid. The catalytic activities in oxidative decomposition of organic dyes were evaluated. The reaction kinetics, effect of ion species and strength, catalytic stability, degradation mechanism, as well as the roles of ZnFe_2O_4 and graphene were also studied. ZnFe_2O_4-rGO showed to be a promising photocatalyst with magnetism for the oxidative degradation of aqueous organic pollutants and simple separation. The combination of ZnFe_2O_4 NPs with graphene sheets leads to a much higher catalytic activity than pure ZnFe_2O_4. Graphene acted as not only a support and stabilizer for ZnFe_2O_4 to prevent them from aggregation, largely improving the charge separation in the hybrid material, but also a catalyst for activating PMS to produce sulfate radicals at the same time. The ZnFe_2O_4-rGO hybrid exhibited stable performance without losing activity after five successive runs.