以均苯四甲酸酐为界面保护剂合成介孔氧化铝

Synthesis of Mesoporous Alumina Using Pyromellitic Dianhydride as Interfacial Protector

以均苯四甲酸酐为界面保护剂、三嵌段共聚物P123为模板剂、乙醇为溶剂、异丙醇铝为铝源,采用溶胶-凝胶法合成了介孔氧化铝,并用XRD、TEM和N2吸附-脱附等手段对试样进行表征,探讨了界面保护剂用量和煅烧温度对产物结构的影响。实验结果表明,均苯四甲酸酐有利于大比表面积和规则介孔氧化铝的合成,当n(均苯四甲酸酐)∶n(Al)=0.20时,可制得孔径大小和形状均一、孔径分布窄并呈短程有序排列的介孔氧化铝。以相同配比制得的试样在400℃下煅烧后,比表面积为474 m2/g,孔体积为0.60 cm3/g,孔径分布集中在3.8 nm处;试样在800℃下煅烧,由无定形氧化铝转变为γ-Al2O3,比表面积为224 m2/g,平均孔径不变。

Mesoporous alumina samples were synthesized by a sol-gel method using pyromellitic dianhydride（PMDA） as the interfacial protector, triblock copolymer P123 as the template, absolute alcohol as the solvent and aluminum isopropoxide as the aluminum source. The products were characterized by means of XRD, TEM and N2 adsorption-desorption. The influences of PMDA dosage and calcination temperature on the structure of the mesoporous alumina samples were investigated. The results show that the addition of PMDA is beneficial to the synthesis of the mesoporous alumina with large specific surface area and ordered pores. When the mole ratio of PMDA to aluminum is 0.20, the resulting samples exhibit uniform channels, narrow pore size distribution and short-distance ordered arrangement. And after calcination at 400 %, the as-synthesized sample has a large surface area of 474 mZ/g, the pore volume of 0.60 cm3/g and the pore size concentrated at 3.8 nm. When it is calcined at 800℃, the phase transformation of the sample occurs from amorphous alumina to 7-A1203 with surface area of 224 mZ/g and the same average pore size distribution.