【摘要】 采用溶胶-凝胶法分别制备了碱土金属氧化物MgO、过渡金属氧化物ZrO₂、稀土金属氧化物CeO₂改性的SiO₂-Al₂O₃复合氧化物，通过XRD、N₂吸附、NH₃-TPD及Py-IR等表征手段考察了助剂MgO、ZrO₂和CeO₂的引入分别对SiO₂-Al₂O₃复合氧化物结构及性质产生的影响。结果发现，SiO₂-Al₂O₃复合氧化物（SA）改性后的比表面积均显著增加。其中，SA-Mg的孔体积和平均孔径较SA减小，SA-Zr、SA-Ce的孔体积则增大。引入MgO后，SiO₂-Al₂O₃复合氧化物总酸量减少，弱酸中心数量稍有增加，B酸中心比例增加。引入ZrO₂后，SiO₂-Al₂O₃复合物表面产生了新的弱酸和中强酸中心，酸量增加明显，同时L酸中心比例大大增加，酸类型由以B酸中心为主转变为以L酸中心为主。CeO₂改性后，SiO₂-Al₂O₃复合氧化物总酸量减少，弱酸中心数量增加，L酸中心比例增加，酸类型以L酸中心为主。更多还原

【Abstract】 SiO₂-Al₂O₃ composite oxides modified by MgO, ZrO₂, and CeO₂ respectively, were prepared using sol-gel method.The effect on the structure and properties of SiO₂-Al₂O₃ composite oxides, after respectively adding MgO, ZrO₂ and CeO₂, was tested based on X-ray diffraction（XRD）, N₂ adsorption, temperature programmed desorption of NH₃（NH₃-TPD）, and FTIR spectroscopy of adsorbed Pyridine（Py-IR）.The experimental results indicate the specific surface area of modified SiO₂-Al₂O₃ composite oxides increased significantly.The pore volume and average pore diameter of SA-Mg were smaller than that of SA, while the pore volume of SA-Zr and SA-Ce was larger than that of SA.After the introduction of MgO, the total acid amount of SiO₂-Al₂O₃ composite oxides decreased, the weak acid amount increased slightly, and B/L value increased.After introducing ZrO₂, the weak and moderate acid amount, as well as the total acid amount increased greatly.SA-Zr was dominated by L acid centers.After modification with CeO₂, the weak acid amount of SiO₂-Al₂O₃ composite oxides increased while the total acid amount decreased.SA-Ce was also dominated by L acid centers.更多还原