Preparation and photocatalytic activity of cerium doped anatase titanium dioxide coated magnetite composite

A composite photocatalyst (Ce-TiO2/Fe3O4) with cerium doped anatase titanium dioxide (Ce-TiO2) shell and a magnetite core was prepared by coating photoactive Ce-TiO2 onto a magnetic Fe3O4 core through the hydrolysis of tetrabutyltitanate in water/oil (w/o) microemulsion with precursors of ammonium ceric nitrate and tetrabutyltitanate in the presence of Fe3O4 nanoparticles. The morphological, structural and optical properties of as-prepared samples were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and UV–vis diffusive reflectance spectroscopy (UV–vis DRS). The effect of cerium content on the photocatalytic activity was studied, and the result reveals that 0.15 mol% Ce-TiO2/Fe3O4 exhibits highest photoactivity. The cerium doping causes absorption spectra of Ce-TiO2/Fe3O4 to shift to the visible region. The photocatalytic activity of the prepared photocatalyst under UV and visible light was estimated by measuring the degradation rate of phenol (50 mg/L) in an aqueous solution and compared to single phase TiO2. The results show that the prepared photocatalyst was activated by visible light and used as effective catalyst in photooxidation reactions. In addition, the possibility of cyclic usage of the prepared photocatalyst was also confirmed. Moreover, Ce-TiO2 is tightly bound to Fe3O4 and can be easily recovered from the medium by a simple magnetic process. It can therefore be potentially applied for the treatment of water contaminated by organic pollutants.