Preparation and photocatalytic activity of Fe3O4@SiO2@ZnO:La

Abstract In this study, Fe3O4@SiO2@ZnO:La microspheres were successfully prepared. The microspheres have the advantages of both ZnO doped with La and the Fe3O4@SiO2 structure such that the former improves the photocatalytic activity of ZnO and the latter can be reused. The X-ray diffraction (XRD), a field emission scanning electron microscope (SEM), a field emission transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and a vibrating sample magnetometer (VSM) were used to characterize Fe3O4@SiO2@ZnO:La microspheres. Methyl orange was used as the model molecule to study the effect of the Zn2+ concentration and the doping amount of La on the photocatalytic activity of Fe3O4@SiO2@ZnO:La microspheres. Results show that in the synthesis of Fe3O4@SiO2@ZnO:La microspheres, photocatalytic activity of the microspheres is enhanced first and weakened later with the increase of Zn2+ concentration. In the La doping process, the photocatalytic activity of Fe3O4@SiO2@ZnO:La microspheres is enhanced with the increase in the La doping amount. The magnetic photocatalysts not only have high photocatalytic activity, but also can be reused. After being reused five times, the photocatalyst's degradation rate of methyl orange is still as high as 81%, which shows that magnetic photocatalysts have prospective wider applications in photocatalytic degradation of dye wastewater.