The Controlling Synthesis Of Nanostructured Crystal TiO₂ In Ionic Liquids And Its Application

Based on the review of the application of Ionic Liquids in the synthesis of nanostructured materials, the controlling preparation of nanostructured crystal TiO₂ in Ionic Liquids and its application were studied systematically. The results showed that Ionic Liquids used in the preparation of TiO₂ has the prominent virtues, such as facilitate direct synthesis of crystalline species under ambient conditions, effective control of the crystal phase and ordering of nanoscale structures. In this dissertation, the main contents discussed were as follows:(1) At 80°C, TiO₂ was synthesized starting from TiCl₄ in two kinds of Ionic Liquids, [Bmim]⁺Cl^- and [Bmim]⁺[BF₄]^-. The XRD results showed that the pure rutile TiO₂ was formed in [Bmim]⁺Cl^-, whereas the crystal phase of the titania was pure anatase when the reaction was carried out in [Bmim]⁺[BF₄]^-. TEM and the N₂ adsorption-desorption results revealed that the nanorods of rutile titania were interaggregated to fabricate a large mesoporous structure and the voids packed in the nanorods formed a small mesoporous, and that anatase TiO₂ consisted of nanoscale particles of single crystal. The above results showed that Ionic Liquid play a very important role in the control of crystal phase and the formation of nanostructure.(2) Considering advantages of feasible controlling micellar nanostructures of nonionic surfactant in Ionic Liquids and [Bmim]⁺[BF₄]^- enhancing the formation of anatase crystal, a series of anatase frameworks were prepared in the nonionic surfactant of AEO₉ and [Bmim]⁺[BF₄]^- The influences of reaction temperature and the content of AEO₉ on the properties of final product were investigated. Under optimum conditions, the sample with anatase framework exhibited wormlike pore structure with pore size of 5.4 nm.(3) The synthesized TiO₂ was used as photocatalyst in the photocatalytic decomposition of MB. The effects of crystal phase, surface area, crystallinity on the photocatalytic activity were investigated. In general, the photocatalytic activity of the samples with anatase phase was higher than that of rutile TiO₂ and under the condition of same crystal phase, the photocatalytic activity enhanced with the increase of crystallinity. In addition, the photocatalytic activity of gold particles loaded TiO₂ was investigated.