Cu (co) Feo <sub> 4 </ Sub>-tio <sub> 2 </ Sub> Composite Prepare Modified Its Photocatalytic Properties

Cu(Co)Fe2O4-TiO2 photocatalysts were successfully prepared via different methods. These photocatalysts were modified by noble metal depositing and metal oxides loading. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetry and differential thermal analysis (TG/DTA), ultraviolet visible diffuse reflectance absorption spectra (UV-Vis DRS), and surface area analyzer (BET) were employed to characterize the as-synthesized samples. The photocatalytic degradation of methylene blue (MB) in aqueous solution, photocatalytic inactivation of Escherichia coli on immobilized CuO/CoFe2O4-TiO2 thin-film and photocatalytic generation of hydrogen in oxalic acid solution were used to evaluate the photocatalytic activity of the photocatalysts.(1) CuO/CoFe2O4 particles were prepared by sol-gel methods and CuO/CoFe2O4-TiO2 composite catalyst was then synthesized by CuO/CoFe2O4 and Degussa P25. Photocatalytic activity of the prepared nanocomposites was tested on the degradation of methylene blue (MB) aqueous solution under visible light irradiation. The results showed that CuO/CoFe2O4 nanoparticles deposited on the Degussa P25 nanopariticles surface were well-dispersed and about 60 nm. The dye photodegradation process was studied considering the influence of experimental parameters such as catalyst type, TiO2 content in CuO/CoFe2O4-TiO2, light intensity, calcination temperature and methylene blue adsorption rate. The material with the best catalytic activity towards the methylene blue photodegradation was the P25 doped with 30% of CuO/CoFe2O4. The degradation rate of MB reached 99.5% under xenon lamp of 250 W within 60 minutes, faster than Degussa P25.(2) Composite photocatalysts of CuO/CoFe2O4-TiO2 were successfully synthesized by a sol-gel method and fixed on ordinary tiles. The photosterilization of Escherichia coli was examined on CuO/CoFe2O4-TiO2 thin films under a xenon lamp irradiation. Disinfection data indicated that CuO/CoFe2O4-TiO2 composite photocatalysts have the much better photocatalytic activity than CuO/CoFe2O4 and TiO2. The optimized composition of the nanocomposites has been found to be mCuO/CoFe2O4:mTiO2=3:7, with loadings range from 790 to 1400 mg·m-2. The photocatalytic inactivated rate of E. coli (105 CFU·mL-1) reached 98.4% under the xenon lamp of 150 W within 30 min.(3) Co3O4/CuFe2O4 powders were prepared by thermal decomposition method, and further combined with TiO2 (Degussa P25) by solid phase method. For comparison, powders were also fabricated by sol-gel method and co-precipitation method. Furthermore, photocatalytic activities of the as-obtained nanocomposites have been evaluated based on the H2 evolution from aqueous oxalic acid solution. Factors such as photocatalysts preparation methods, Co3O4/CuFe204 to TiO2 weight ratio in the composites, sacrificial reagents type, durability and noble metals loaded affecting the photocatalytic hydrogen producing have been studied in detail. The results showed that the nanocomposite of Co304/CuFe204-Ti02 70% (wt %) was more efficient than their single part of Co3O4/CuFe2O4 or TiO2 in producing hydrogen. Loading Pt on the surface of Co3O4/CuFe2O4-TiO2 can improve the photocatalytic activity, and the average hydrogen production rate is up to 876.8μmol·h-1.