【摘要】 采用正硅酸甲酯和钛酸丁酯作为硅和钛的前驱体,在溶胶-凝胶过程中添加非离子表面活性剂C16EO10作为结构导向剂合成双孔结构硅钛复合氧化物材料。扫描电镜(SEM)以及N2吸附/脱附法分析表明,材料具有三维连续大孔和骨架介孔的双孔分布结构。通过骨架元素分析(EDS)和X射线衍射分析可知,制备过程中添加的钛可以全部进入凝胶骨架中,且钛在骨架中的分散性较好。采用Hammett指示剂法和吡啶吸附红外光谱法分析了材料表面固体酸性,结果显示,硅钛复合氧化物属于中强酸,酸强度H0在-5.6~-3.0之间的酸中心数大约为0.30 mmol/g左右。硅钛材料表面含有较丰富的L酸位和相对较少的B酸位。更多还原

【Abstract】 Bimodal porous titania-silica composite oxide were prepared via sol-gel method with an addition of nonionic surfactant C16EO10 as the structure-directing agent.Tetramethoxysilane and titanium tetrabutoxide were used as the silicon and titanium precursors,respectively.Scanning electron microscopy and N2 adsorption/desorption measurements indicated that the composite oxide in possession of interconnected macropores and texture mesopores.By means of energy dispersive spectroscopy and X-ray diffraction,it was proved that the initially added titanium could be totally incorporated in the gel network and highly dispersed.The acidity characters of titania-silica were studied by Hammett indicator method and infrared spectroscopy.Experimental results showed that titania-silica composite oxide synthesized by sol-gel method were mild strong solid acids,contained abundant Lewis acid sites and relatively poor Brnsted acid sites,and the mount of acid with acid strength H0 of-5.6~-3.0 was 0.30 mmol/g.更多还原