The Study Of Preparation,Characterization And Property Of Titanian Hollow Spheres With Mesoporosity

Titania hollow sphere has attracted a lot of attentions due to its advantages, such as high specific surface areas, high permeability and low density. The traditional methods for its preparation include template method, sol-gel method and so on. During the preparation by these methods, many kinds of organic solvents and strong acids should be added, which results high costs, environmental demage and low stability. The spray drying method has the advantages such as continuous operation, high automation and easy process, the powders prepared by this method possess good purity, good control of morphology, so the mehod is widely applied in the materials preparation.The peroxo titanic acid sol was used as a precursor in the paper for its neutral pH, friendness to environment and low cost. TiO2hollow sphere was fabricated by a spray drying method and calcination subsequent, furthermore, Pt/TiO2catalyst with hollow sphere was prepared by a NaBH4reduction. The morphology, crystal phase and microstructure of the samples were characterized by SEM, XRD, XPS and TEM,and the photocatalytic property of the samples was measured by the degradation of methyl orange.Based on the above works, the following conclusions were drawn:(1) The formation of the hollow sphere structure of the sample is related to the temperature of the inlet air during the spray drying, in which the feed rate of the hot air during the spray drying played a weak important role. TiO2hollow sphere with uniform dispersity could be gotten when the temperature of the inlet air is120℃to180℃. In this case, the average diameter of the sample particle is about2μm, and it increases along with the temperature of the inlet air. BET analysis shows that when the temperature of the inlet air is160℃and the feed rate of the hot air is900mL/h, the specific surface area of the sample is the largest, the photocatalytic property of the sample is the best, and the degradation rate of the sample for MB can reach86.2%under UV irradiation for2.5h.(2) Pt/TiO2catalyst loading1%platinum with hollow sphere was prepared by NaBH4reduction using TiO2hollow sphere as support. XRD, XPS and TEM results show that Pt particle, with a diameter around4nm, had been loaded on the surface of the support TiO2successfully. Compared to the support, TiO2hollow sphere, the apparent rate constant of Pt/TiO2is improved by18.4%. This indicates that the loading of platinum is one of the efficious approach to improve the photocataltic property of TiO2hollow sphere.