SYNTHESIS, CHARACTERIZATION, AND PHOTOCATALYTIC ACTIVITY OF Fe3O4@ZnO NANOCOMPOSITE

A magnetic Fe3O4@ZnO nanocomposite (NC) was successfully synthesized by a wet millingmethod using a high energy milling (HEM) machine. The magnetic Fe3O4@ZnO NC was
characterized by an X-ray Diffractometer (XRD), scanning and transmission electronmicroscopes (SEM and TEM), and a vibrating sample magnetometer (VSM). X-ray diffraction
results show that Fe3O4@ZnO NC consisted of ZnO and Fe3O4 phases. The microstructure analysis indicated that Fe3O4@ZnO NC presented a ZnO shell wrapped around the surface of a
magnetic Fe3O4 surface. The average diameter of the aggregated Fe3O4 nanoparticle (NP) is 20nm, while that of Fe3O4@ZnO NCs is nearly 30 nm. The Fe3O4 NP and Fe3O4@ZnO NC show typical superparamagnetic behavior with low coercivity. The saturation magnetization (Ms) of Fe3O4 NP was measured at about 66.26emu.g-1 and then declined to 34.79emu.g-1 after being encapsulated with a ZnO shell. The photoactivities of the Fe3O4@ZnO NC under UV
irradiation were quantified by the degradation of a methylene blue (MB) dye solution. The
result reveals that the photodegradation efficiency of Fe3O4@ZnO NC is favorable at pH
neutral (pH = 7) reaching 100%. By increasing the MB dye concentration from 10 ppm to 40
ppm, the photodegradation efficiency decreases from 100% to 52%. The Fe3O4@ZnO NC can
be easily collected by an external magnet. The magnetic Fe3O4@ZnO NC could be extended to
various potential applications, such as purification processes, catalysis, separation, and
photodegradation.
Keywords: Fe3O4@ZnO nanocomposite; Methylene blue; Photocatalytic activity;
Photodegradation; Wet milling