Preparation And Properties Of A Novel Magnetic Ferric Trioxide / Tungstate Composite Photocatalyst

Photocatalytic degradation of organic pollutants by semiconductor photocatalyst has a wide application prospect in environmental purification. Due to its various morphologies and structures, simple synthesis, stable chemical properties and some other advantages, tungstate has been regarded as one of the most promising photocatalysts, showing high photocatalytic activity on water decontamination. However, big reduce and difficult recovery of the traditional powder photocatalyst during water treatment process may greatly limit its widely and practical use. In recent years, preparation and properties of the core-shell structured magnetic photocatalyst have attracted more and more interest and attention. With magnetic microspheres as the core and tungstate nanoparticles as the shell, the magnetic composite photocatalyst can not only retain as high catalytic activity as powder photocatalyst, but also can be easily recovered by magnetic separation, which makes it much more valuable in practical application.In this paper, we focused on the synthesis and characteriazations of the novel magnetic Fe3O4@tungstate composite photocatalyst. Moreover, we also fabricated new visible-light-driven tungstate photocatalyst using a green synthesis method. And we further discussed both its growth mechanism and the influence factors on its photocatalytic activity. The main results can be summarized as follows:1. Fe3O4@ZnWO4composite microspheres with magnetically recyclable photocalytic performance have been firstly synthesized by a simple refluxing method under mild conditions. And the properties of the as-synthesized products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Vibrating Sample Magnetometer (VSM). The as-prepared Fe3O4@ZnWO4composites show good photocatalytic efficiency in degradation of rhodamine B (RhB) under UV light irradiation and can be recycled five times by magnetic separation without major loss of activity, the magnetic property of Fe3O4@ZnWO4sample has been studied also. Microspheres show potential use on dye degradation from the solution considering their magnetic recovery properties.2. Fe3O4/Bi2WO6composite microspheres with core-shell structure have been fabricated in a facile and safe refluxing way. The surface of these microspheres with inner magnetite core are decorated by Bi2WO6nanoparticles. With the help of H2O2, such fabricated Fe3O4/Bi2WO6composites showed good and fast visible-light driven photocatalytic performance on nearly total degradation of rhodamine B (RhB) in aqueous system. Moreover, they can be easily harvested from aqueous solution for recycle upon applying an external magnet. Therefore, such combined Bi2WO6photocatalytic activity and Fe3O4magnetic property endows such composite with a bright perspective in low cost wastewater treatment by taking full advantage of solar energy.3. Three dimensional highly hierarchical flower-like Bi2WO6microspheres self aggregated by nanoplates have been fabricated in a green hydrothermal way at low temperature, without using any template or setting a certain pH value in solution. We investigated the formation mechanism and also studied visible-light-driven photocatalytic activities of as obtained flower-like Bi2WO6microspheres, which indicated their excellent performance on degradation of organic dye under visible light irradiation. Such cost effective way introduced to get well-organized flower-like Bi2WO6microspheres shows potential application on water treatment industry by full use of solar light.