无机盐和有机醇盐制备Al_2O_3干凝胶

Al_2O_3 XEROGELS SYNTHESIZED BY INORGANIC SALT AND ORGANIC ALKOXIDE

分别以廉价的硝酸铝无机盐常压干燥法和异丙醇铝有机醇盐作为铝源,采用溶胶-凝胶法制备了结构完整的SiO2-Al2O3干凝胶和纯Al2O3干凝胶。利用热重-差热分析、Fourier转换红外吸收谱、氮气吸附和电子显微镜等实验手段,对比研究了两种制备方法对材料性能的影响。结果表明:由无机盐制备的SiO2-Al2O3干凝胶是以SiO2构成网络骨架,形成一定数量的Si—O—Al键,并保持了干凝胶纳米多孔的特点;而有机醇盐制备的Al2O3干凝胶孔隙分布更为均匀。采用两种不同铝源制备的干凝胶,均是纳米颗粒组成的多孔结构,并均具有较高的比表面积和较窄的孔径分布。

Integrated structure SiO2-Al2O3 xerogels and pure Al2O3 xerogels were prepared by the sol-gel method and non-supercritical drying using low-cost inorganic aluminum nitrate trihydrate and organic aluminum-isopropoxide alkoxide as aluminum sources respectively. The differences in the characteristics of these xerogels were investigated by means of thermogravimetry-differential thermal analysis, Fourier transform infrared spectroscopy, nitrogen adsorption experiments and scanning electron microscope. The results show that some hetero-linkage Si-O-AI bonds form based on SiO2 frameworks for SiO2-Al2O3 xerogels, prepared by inorganic salt, and the xerogels maintain mesoporous characteristics of nano-particles, but the pore distribution is more homogeneous for pure Al2O3 xerogels prepared by organic alkoxide. These two kinds of materials consisting of nano-particles have mesoporous structures, a high specific surface area and relatively sparse pore distribution.