Solvothermal synthesis of nanostructured TiO2 photocatalyst in supercritical CO2 fluids.

Abstract: Nano-sized titanium dioxide TiO2 photocatalysts were successfully prepared by solvothermal method under various supercritical conditions. A solvothermal process with the starting precursor of tetrabutyl orthotitanate (TBOT) and ethanol mixture in supercritical CO2 (SC–CO2) environment under different reaction temperature and pressure has been developed for the fabrication of nanostructured TiO2. Nano-sized TiO2 samples obtained exhibited various morphologies and different photocatalytic ability. The influence of reaction temperature and pressure on morphologies and photocatalytic activity of TiO2 products was discussed and analyzed according to the Ostwald Ripening Rules. Characterization of the TiO2 products consisted of XRD, SEM and TEM methods and photocatalytic activity was evaluated by the degradation of methyl orange (MO). [Copyright &y& Elsevier]