Preparation of Nanoporous TiO2/SiO2 Composite with Rice Husk as Template and Its Photocatalytic Property

TiO2/SiO2 nanoporous composite with high anatase content, high specific surface area and good photocatalytic activity was prepared by sol-gel process using rice husk (RH) as template. The thermal behavior, the microstructure and the chemical composition of the composite were characterized by TG-DSC, XRD, FESEM, EDS and nitrogen physisorption. The results show that the transformation of TiO2 from anatase to rutile begins at 700–800 °C and completes at about 1000 °C. When the TiO2/SiO2 nanoporous composite is annealed at 500 or 600 °C, nano-TiO2 cells are arranged in linear ridges and furrows, and the catalytic activity points are formed. Along with the increase of treatment temperature, nano-TiO2 cells form a layered structure on the surface and fill the pores of RH. TiO2/SiO2 nanoporous composite annealed at 500 °C exhibits the highest photodegradation efficiency of methyl blue, which is about 82% within 4 h.