Magnetic core–shell Fe3O4@SiO2@ZnO hybrids for visible light photocatalysis of methylene blue

The superparamagnetic Fe₃O₄ is synthesized by solvothermal method, in which the glycol as reducing agent and medium using FeCl₃ as the Fe sources. The superparamagnetic Fe₃O₄@SiO₂ was synthesized by the system which is composed by ethanol, water, ammonia and ethyl orthosilicate. The property of the Fe₃O₄, Fe₃O₄@SiO₂ and Fe₃O₄@SiO₂@ZnO is characterized by XRD, TEM, Vsm and UV/vis spectrum. The TEM results indicate that spheres structure of Fe₃O₄ and Fe₃O₄@SiO₂ are synthesized. These nanoparticles are detected by Vsm detection for superparamagnetic property. The inverse spinel structure of Fe₃O₄ is polycrystalline, which is constructed by Ostwald ripening effect. The photocatalytic activity of Fe₃O₄@SiO₂@ZnO was characterized by degraded methylene blue under the visible light-driven. The results show that the photocatalytic property of Fe₃O₄@SiO₂@ZnO is enhanced after visible light irradiated for degrading methylene blue. The Fe₃O₄ and Fe₃O₄@SiO₂ nanomaterials are recycled and reused because of the superparamagnetic property. The Fe₃O₄@SiO₂@ZnO nanomaterials show high catalytic activity and excellent stability according to the decomposition of methylene blue after recycled and reused several times.