TiO2-SiO2复合气凝胶：常压干燥制备及性能表征

以廉价的四氯化钛和工业水玻璃为原料,通过溶胶-凝胶法制得TiO2-SiO2复合湿凝胶,用三甲基氯硅烷(TMCS)/乙醇(EtOH)/正己烷(Hexane)混合溶液对湿凝胶进行改性,常压干燥制备了TiO2-SiO2复合气凝胶.利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、红外光谱(FTIR)、X射线衍射(XRD)及N2吸附/脱附法对复合气凝胶的形貌和性质进行了分析.结果表明,TiO2-SiO2复合气凝胶具有连续多孔结构,150℃干燥后复合气凝胶的比表面积为1 076 m2·g-1,孔体积为4.96 cm3·g-1;经550 ℃热处理后,复合气凝胶仍然具有高的孔隙率,比表面积为856 m2·g-1,孔体积为3.46 cm3·g-1.吸附和光催化降解罗丹明B的结果表明,复合气凝胶同时具有较好的吸附和光催化性能,其吸附/光催化协同作用活性优于纯SiO2气凝胶和锐钛矿TiO2粉末;且重复利用四次降解率仍然可达到89%.

TiO2-SiO2 Composite Aerogel: Preparation by Ambient Pressure Drying Process and Characterization

Using cheap titanium tetrachloride and industrial waterglass as raw materials, TiO_2-SiO_2 composite aerogels were prepared via an ambient pressure drying process, by using Trimethylchlorosilane /Ethanol/Hexane solution to modify the sol-gel-derived TiO_2-SiO_2 wet gel. The morphology and properties of the aerogels were characterized by SEM, TEM, FTIR, XRD and N_2 adsorption-desorption measurement. The results indicate that the obtained TiO_2-SiO_2 composite aerogels exhibit a porous structure, with a specific surface area of 1 076 m~2·g~(-1) and pore volume of 4.96 cm~3·g~(-1) after dried at 150 ℃. Moreover, the composite aerogels still show high porosity after calcined at 550 ℃, with a specific surface area of 856 m~2·g~(-1) and pore volume of 3.46 cm~3·g~(-1). The results of adsorption and photocatalytic degradation of rhodamine B show that TiO_2-SiO_2 composite aerogels have both good adsorption and photocatalytic properties. The synergistic adsorption/photocatalysis activity of TiO_2-SiO_2 composite aerogels was better than pure SiO_2 aerogels and pure anatase TiO_2 powder. Additionally, the adsorption/ photocatalytic degradation rate is still up to 89% after being used for four times.