pure and different content europium （Eu） doped mesoporous titania were prepared by template method using Eu（NO3）3·6H2O and Ti（OC4H9）4 as precursors and Pluronic P123 as template and characterized with X-ray diffraction （XRD）, N2 adsorption-desorption measure- ments, and ultraviolet-visible diffuse absorption spectra. Their photocatalytic activities were studied by photodegradation phenol in water un- der visible light irradiation. The results showed that Eu doping restrained the growth of grain size and extended the photoabsorption edge of mesoporous titania into the visible light region, which made Eu-doped mesoporous titania possess high photocatalytic activity under visible light. In the experiment condition, the photocatalytic activity of 0.2 mol.% Eu doped mesoporous titania was optimal of all the prepared samples.
A novel kind of magnetically separable photocatalyst of cerrium-doped mesoporous titanium dioxide coated magnetite （Ce/MTiO2/ Fe3O4） was prepared and its activities under UV and visible light were reported. The catalysts with Ce/MTiO2 shell and Fe3O4 core were prepared by coating photoactive Ce/MTiO2 onto a magnetic Fe3O4 core through the hydrolysis of tetrabutyltitanate （Ti（OBu）4, TBT） with precursors of ammonium ceric nitrate and TBT in the presence of Fe3O4 particles. The MTiO2 shell was for photocatalysis, the Fe3O4 core was for separation by the magnetic field and the doped Ce was used to enhance the photocatalytic activity of MTiO2. The morphological, structural and optical properties of the prepared samples were characterized by Bnmauer-Emmett-Teller （BET） surface area, transmission electron microscopy （TEM）, X-ray diffraction （XRD） and UV-vis absorption spectroscopy. The effect of cerrium-doped content on the photocatalytic activity was studied and the result revealed that 0.5 mol.% Ce/MTiO2/Fe3O4 exhibited highest photoactivity. The photocatalytic activities of obtained photocatalysts under UV and visible light were estimated by measuring the degradation rate of methylene blue （MB, 50 mg/L） in an aqueous solution. The results showed that the prepared photocatalyst was activated by visible light and used as effective catalyst in photooxi- dation reactions. In addition, the possibility of cyclic usage of the prepared photocatalyst was also confirmed. Moreover, Ce/MTiO2 was tightly bound to Fe3O4 and could be easily recovered from the medium by an external magnetic filed. So, the photocatalyst can be reused without any mass loss. It can therefore be potentially applied for the treatment of water contaminated by organic pollutants.
