Effect of TiO_2 Sol Impregnation on Biogenic Hierarchical Porous Structure of Rice Husk after High Temperature Treatment

Biogenic hierarchical porous rice husk SiO2samples were prepared from pre-treating rice husk( RH) at low temperatures following TiO2sol impregnation and pyrolysis process. The samples were characterized by scanning electron microscopy,X-ray diffraction and energy dispersive spectrometer. Biogenic hierarchical porous structure of untreated RH SiO2starts to crack and break down from 800 ℃,whereas TiO2grain film is formed on the pore wall and surface of RH SiO2after sol impregnation and heat treatment, which enhances the skeleton strength; the biogenic hierarchical porous structure of the rice husk still maintains after firing at 1 400 ℃.