Studies On Preparation, Characterization And Properties Of TiO₂ Nano Powder And Ce～(3+) Doped TiO₂ Nanofibers

Nano titania has favorable biological and chemical inertness, strong oxidizability, low cost and long-term stability against photocorrosion and chemical corrosion as a novel nano material. The specific area of titania nanofibers are much larger than that of the titania nano powders and the photocatalysis degradation ratio of tintania nanofibers is more efficient with lower cost than that of titania nano powders. Therefore, it is of great significance in the practical applications.Firstly, butyl-titanate was used as precursor and the titania nanopowders were prepared by sol-emulsion-gel method. According to the experimental results, the optimum ratio of the materials was obtained. To prepare optional nanofiber precursor, the ratio of Butyl-titanate and Cyclohexanol should be at 10:100, the concentration of CATB should be 0.5g/20ml; the pH value should be about 8.4.Then the properities of the nanofibers are studied. After the powders calcinated in different temperatures, The phase of the powders changed absolutely to anatase from amorphous phase at 550℃, the average size of the particles was about 14nm. And gradually changed to rutile by heat treatment at 750℃. 1g titania powders could degrade 10mg/L methylene blue 1L and the rate reached 80% in 20 minutes.Titania nanofibers were prepared by means of reflux in basic solutions. The formation mechanism of the nanofibers was discussed. The fibers had been formed in the process of reflux. After acting with the HCl,H-titanate was formed. And the titania was formed after further dehydration. The characteristics of the nanofibers in different temperatures were examined which show that the fibers exhibit well dispersion for the uncalcinated fibers, but heat-treatment lead to aggregation. The slenderness ratio is about 20. 0.25g titania nanofibers could degrade 10mg/L methylene blue 1L and the rate reached 70% in 30 minutes.Finally, Ce was doped in the fibers. There is 58% Ce filled in the crystal frame. The characteristics of the doped fibers were investigated. With the increase of the doped quantities the photocaytalytic activity increased.