TiO 2 Properties And Photocatalytic Doped Polymer Gel Method

Titanium dioxide semiconductor is considered to be one of the most promising photocatalytic materials due to its high photocatalytic activity, chemical stability, nontoxicity and low cost. Unfortunately, titanium dioxide as photocatalytic material still has two main disadvantages:TiO2band gap is wide and absorded by shorter wavelength UV with low utilization of solar engery and the high recombination rate of photo-generated carrier results in low photocatalytic efficiency. These disadvantages limit the large scale production and application of TiO2. In view of the current titanm dioxide photocatalyst problems, many researchers have done a lot of research work through titanm dioxide modification. Among them, the metal ion doped with significant effect and become the most common method.In this thesis,(Fe/Ce) doped and co-doped TiO2powders were prepared by polyer network gel method. The optimal parameters of (Fe/Ce) doped TiO2powders were obtained by using the orthogonal experiment design method. Characterization by TG-DTA, FT-IR, XRD, BET, UV-Vis techniques the product of weight change and thermal effect, structure, composition and optical properity, explored the influence of experimental conditions on the properity of TiO2powders, get the following conclusion:(1) The orthogonal experimental results show that various factors affect the light absorption band edge of Fe-doped TiO2as follows:the amount of Fe3+doped> the calcination temperature> the pH value> the ratio of monomer and crosslinking agent. The best reaction conditions:the amount of Fe3+doped is1.5mol%, the pH value is8.5, the ratio of monomer and crosslinking agent is5:1, the calcination temperature is700℃. Various factors affect the light absorption band edge of Ce-doped TiO2as follows:the amount of Ce3+doped> the calcination temperature> the ratio of monomer and crosslinking agent> the pH value. The best reaction conditions:the amount of Ce3+doped is1.5mol%, the pH value is9.5, the ratio of monomer and crosslinking agent is8:1, the calcination temperature is500℃.(2) The XRD and UV-Vis results show that Fe3+doped do not change the crystal structure of TiO2and promote the transition of anatase to rutile, at the same time, it can also improve the dispersion of titanium dioxide powder. The calcination temperature and the amount of Fe3+doped have great influences on the absorption spectra and light catalytic activity of titanium dioxide powder. When the amount of Fe3+doped is1.5mol%and the calcination temperature is650℃, the product has the optimal visible light activity and its light absorption band edge is548.2nm.(3) The XRD and UV-Vis results show that Ce3+doped restrain the transition of anatase to rutile, at the same time, it can also refine grain make doped titanium dioxide powder has a larger surface area. The calcination temperature and the amount of Ce3+doped have great influences on the absorption spectra and light catalytic activity of titanium dioxide powder. When the amount of Ce3+doped is1.5mol%and the calcination temperature is650℃, the product has the optimal visible light activity and its light absorption band edge is543.3nm.(4) Iron cerium co-doped titanium dioxide powders were prepared by polyer network gel method. Due to the cooperative effect of Fe3+and Ce3+, so that the light absorption band edge redshift of titanium dioxide is most obvious, up to556.8nm.