Synthesis of Tl-Ce-SI Binary and Ternary Nanocomposite Photocatalyst by Supercritical Fluid Drying Technology

摘要

Ti-Ce, Ti-Si binary and Ti-Ce-Si ternary novel nanocomposite oxide photocatalysts were prepared with cheap inorganic salts T1Cl_4, Na_2SiO_3.9H_2O and Ce(NO_3)_3.6H_2O 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 SiC"2 and CeO_2 in XRD patterns indicate that a SiO_2 amorphorous phase exists in all the samples and CeO_2 is well dispersed on the surface of TiO_2. The orthogonal test was designed to optimize the preparing conditions. It is found that ceria doping enhances the photocata-lytic activity markedly, and the optimum doping of CeO_2 is 0.1 percent , 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 SiO_2. Heat-treatment is a necessary factor to induce chemistry change of Ti-Si surface. The optimum heat-treating temperature is 600 t . 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.