Effect of PEG with different MW as template direction reagent on preparation of porous TiO2/SiO2 with assistance of supercritical CO2

Titania–silica composite have been prepared using polyethylene glycol (PEG) with different molecular weights ( M w ), PEG20000, PEG10000, and PEG2000, as template in supercritical carbon dioxide (SC CO 2 ). The composite precursors were dissolved in SC CO 2 and impregnated into PEG templates using SC CO 2 as swelling agent and carrier. After removing the template by calcination at suitable temperature, the titania–silica composite were obtained. The composite were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and nitrogen sorption–desorption experiment. Photocatalytic activity of the samples has been investigated by photodegradation of methyl orange. Results indicate that there are many Si–O–Ti linkages in the TiO 2 /SiO 2 composite; the PEG template has a significant influence on the structure of TiO 2 /SiO 2 . In addition, the TiO 2 /SiO 2 prepared with PEG10000 exhibited high photocatalytic efficiency. So this work supplies a clue to control and obtain the TiO 2 /SiO 2 composite with different photocatalytic reactivity with the aid of suitable PEG template in supercritical CO 2 .