pH摆动-共沸蒸馏法制备高比表面大孔容介孔纳米氧化铝

摘要

以硫酸铝为铝源,氨水为沉淀剂,采用pH摆动法辅以共沸蒸馏处理制备γ-Al2O3前驱体,经550℃焙烧得到了γ-Al2O3.采用XRD、BET法、SEM、TEM等手段对γ-A12O3进行表征.pH摆动法在反应温度80℃,pH摆动3次,不需额外老化条件制备的γ-A12O3比表面积、平均孔径、孔容最大,样品无规则形貌;辅以共沸蒸馏处理可制备分散性良好、粒径均匀的介孔纤维状纳米γ-Al2O3,平均粒径宽5nm,长40-60nm,与PH摆动法制备样品相比,比表面积相当,高达327m2/g,孔径、孔容提高很大,达到16.04nm和1.31cm3/g.%Precursors of objective γ-Al2O3 were prepared from Al2(SO4)3 and NH4OH by pH swing precipitation method combined with azeotropic distillation. The γ- Al2O3 powders were obtained from the precursor after calcination at 550℃ and were characterized by means of XRD,BET,SEM and TEM. The morphology of γ-Al2O3 powders obtained from pH swing precipitation method is irregular. The specific surface area,average pore size,pore volume of γ-Al2O3 powders are biggest whcn reaction temperature is 80℃ and pH swing times is 3 without aging time. The fibrous nano mesoporous γ-Al2O3 powders obtained from pH swing precipitation method combined with azeotropic distillation are uniform in particle size dislribution with large pore volume,large average pore size and bigh specific surface area. The average pure size is 16. 04nm; pore volume is 1. 31cm3/g;specific surface area is 327m2/g,average particle width is 5nm and average particle length is 40-60nm.