Size-controllable synthesis of Fe3O4 nanoparticles through oxidation-precipitation method as heterogeneous Fenton catalyst

The particle size of Fe3O4 nanoparticles is controlled using a simple oxidation-precipitation method without any surfactant. The structure, morphology and physical properties of the synthesized Fe3O4 NPs were characterized using x-ray diffraction, scanning electron microscopy, transmission electron microscopy, x-ray photoelectron spectroscopy, Brunauer-Emmett-Teller, and vibrating sample magnetometer. As-prepared magnetite samples exhibited spherical morphology with average diameters of 30, 70, 250, and 600 nm, respectively. Activity of the synthesized Fe3O4 NPs was evaluated for the Fenton-like reaction, using rhodamine B (RhB) as a model molecule. The results showed that catalytic activity increases with the reduced particle size. The significant higher catalytic activity of the fine Fe3O4 NPs mainly originated from the higher specific surface area, due to the increase in exposed active site number and adsorption capacity. The reusability of 30 nm Fe3O4 NPs was also investigated after three successive runs, in which the RhB degradation performances showed a slight difference with the first oxidation cycle. This investigation is of great significance for the promising application of the heterogeneous Fenton catalyst with enhanced activity in the oxidative degradation of organic pollutants.