Preparation of titania/silica mesoporous composites with activated carbon template in supercritical carbon dioxide

Titania/silica mesoporous composites have been prepared with nanoscale casting process using activated carbon as template in supercritical carbon dioxide (SC CO2). The composite precursor of tetrabutyl titanate and tetraethyl orthosilicate (TEOS) were dissolved in supercritical CO2, and then coated on activated carbon in the desired supercritical condition. After removal of activated carbon template by calcinations in air at 600 °C, TiO2/SiO2 mesoporous composite was obtained. The effects of CO2 pressure and temperature have been studied on the coating ratio during the supercritical condition. The products were characterized by XRD, nitrogen sorption isotherms, SEM and TEM. SEM result indicates that the composite product has pretty well porous structure and the product pore structure information had been calculated from the nitrogen sorption isotherms. The titanium dioxide was in anatase phase and the largest BET surface area is up to 318.70 m2/g. TEM experimental result shows that in the composite product, some titania nano-wire was formed.