Fabrication and characterization of Fe_3O_4@SiO_2@TiO_2@Ho nanostructures as a novel and highly efficient photocatalyst for degradation of organic pollution

In this work we synthesize a novel and highly efficient photocatalyst for degradation of methyl orange and rhodamine B. In addition, a new method for synthesis of Fe₃O₄@SiO₂@TiO₂@Ho magnetic core-shell nanoparticles with spherical morphology is proposed. The crystal structures, morphology and chemical properties of the as-synthesized nanoparticles were characterized using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDS), X-ray diffraction (XRD), UV–vis diffuse reflectance spectroscopy (DRS) and vibrating sample magnetometer (VSM) techniques. The photocatalytic activity of Fe₃O₄@SiO₂@TiO₂@Ho was investigated by degradation of methyl orange (MO) as cationic dye and rhodamine B (RhB) as anionic dye in aqueous solution under UV/vis irradiation. The results indicate that about 92.1% of RhB and 78.4% of MO were degraded after 120 and 150 min, respectively. These degradation results show that Fe₃O₄@SiO₂@TiO₂@Ho nanoparticles are better photocatalyst than Fe₃O₄@SiO₂@TiO₂ for degradation of MO and RhB. As well as, the catalyst shows high recovery and stability even after several separation cycles.