Magnetic nanocomposite based on titania–silica/cobalt ferrite for photocatalytic degradation of methylene blue dye

Abstract Magnetic photocatalysts were successfully prepared by coating titania–silica (TiO 2 –SiO 2 ) on cobalt ferrite (CoFe 2 O 4 ) nanoparticles. A simple organic acid precursor method was employed to prepare the magnetic part, while the TiO 2 –SiO 2 was synthesized and coated onto CoFe 2 O 4 by the sol–gel technique. Controlling the modification process of TiO 2 –SiO 2 with CoFe 2 O 4 nanoparticles is a key factor for obtaining appropriate catalytic performance. Under optimized conditions, a core–shell structure could be obtained in which CoFe 2 O 4 is a core while TiO 2 –SiO 2 forms a shell. The current photocatalyst exhibits remarkable catalytic activity for the degradation of methylene blue dye in water under UV irradiation. It was demonstrated that the catalyst could remove as high as 98.3% of the organic dye in just 40 min. The degradation efficiency was found to depend essentially on initial dye concentration, solution pH and the catalyst loading. The as-synthesized catalyst was characterized by different techniques including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy and N 2 adsorption–desorption isotherm. The photocatalyst could be removed from the reaction mixture and its recyclability remains effective and active after six cycles.