Photocatalyst materials were prepared as a hybrid between TiO2 /SiO2 via low temperature
hydrothermal method (150oC) without further heat treatment. Porous silica from rice husk ash was
used as a support for fine TiO2 particles which acted as a photocatalyst when radiated with a UV light.
TiO2-deposited SiO2 was successfully prepared through hydrolysis of TiOSO4 solution by controlling
synthesis parameters such as pH ,concentration of TiOSO4, temperature and time under hydrothermal
treatment. The obtained products were characterized for physical and chemical properties by means of
XRD, XRF, BET and TEM . It was found that pH had an influence on the crystallization of TiO2, and
under an appropriated pH, only anatase presented along with amorphous phase. High crystallinity of
nano-crystalline anatase ( about 5 nm) deposited on silica surface was observed through TEM.
Adsorption and photocatalytic performances of the prepared catalyst were evaluated in methylene
blue aqueous solution in the dark and under ultraviolet ray irradiation, respectively. Due to the
synergetic functions of adsorption by porous substrate and decomposition by TiO2 photocatalyst, an
enhancing of photocatalytic activity for decomposition of organic pollutants in water under UV rays
was obtained.
Effect of Temperature and pH on Phase Transformations in Citric Acid Mediated Hydrothermal Growth of Tungsten Oxide
