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

摘要

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 CO2).The composite precursors were dissolved in SC CO2 and impregnated into PEG templates using SC CO2 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 photo-degradation of methyl orange.Results indicate that there are many Si-O-Ti linkages in the TiO2/SiO2 composite;the PEG template has a significant influence on the structure of TiO2/SiO2.In addition,the TiO2/SiO2 prepared with PEG 10000 exhibited high photocatalytic efficiency.So this work supplies a clue to control and obtain the TiO2/SiO2 composite with different photocatalytic reactivity with the aid of suitable PEG template in supercritical CO2.