Reduced graphene oxide anchored magnetic ZnFe2O4 nanoparticles with enhanced visible-light photocatalytic activity

We report a facile approach to immobilize magnetic ZnFe2O4 nanoparticles (NPs) onto a reduced grapheme oxide (rGO) network by using highly reactive ZnOx(OH)y and FeOx colloids as precursors, which were respectively obtained by laser ablation of metallic zinc (Zn) and iron (Fe) targets in pure water. A microstructure investigation of such nanocomposites (NCs) revealed that ZnFe2O4 NPs are well-dispersed onto rGO sheets. Such a structure was helpful for separating the photoexcited electron-hole pairs and accelerating the electrons transfer. Electrochemical impedance measurements indicated the remarkable decrease of the interfacial layer resistance of the composite structure compared to that of pure ZnFe2O4 NPs. As a result of these advantages, such NCs present a prominent enhancement in the photodegradation efficiency for methylene blue dye. Besides, the excellent magnetic properties of the ZnFe2O4 NPs allow the catalysts to be easily separated from the solution by a magnet for recycling. This effort not only provided a new approach to fabricate ZnFe2O4-rGO NCs, also expanded the application of ZnFe2O4 NPs used as visible-light excited photocatalysts in application of organic pollutants degradation.