Synthesis of Ti-Ce-Si Binary and Ternary Nanocomposite Photocatalyst by Supercritical Fluid Drying Technology

Ti-Ce, Ti-Si binary and Ti-Ce-Si ternary novel nanocomposite oxide photocatalysts were prepared with cheap in organic salts TiCl4, Na2SiO3·9H2O and Ce(NO3)3·6H2O as precursors by supercritical fluid drying (SCFD) technology. The catalysts were characterized by means of XRD and TEM. The particle size of nanocomposite oxide photocatalysts synthesized by SCFD method is about 6 ∼ 11 nm, which is smaller than those obtained by common drying method (CD). The phase transformation from anatase to rutile was inhibited by SCFD technology. The peaks of SiO2 and CeO2 in XRD patterns indicate that a SiO2 amorphorous phase exists in all the samples and CeO2 is well dispersed on the surface of TiO2. The orthogonal test was designed to optimize the preparing conditions. It is found that ceria doping enhances the photocatalytic activity markedly, and the optimum doping of CeO2 is 0. 1 %. The thermal stability of photocatalyst can be improved; the growth of particle-size and the decrease of surface area can be prohibited by doping of SiO2. Heat-tieatment is a necessary factor to induce chemistry change of Ti-Si surface. The optimum heat-treating temperature is 600 °C. A novel and efficient Ti-Ce-Si ternary nanocomposite was prepared by SCFD method with strong thermal stability and high photoactivity in the photodegratation of phenol.