壳壁上具有介孔的Si/Al复合氧化物中空微球的制备

近年来，由于中空的球形材料具有良好的表面渗透性、低密度和高比表面积等性质而受到人们的普遍关注，在无机中空球的制备过程中，所采用的方法大多为模板法，合成的无机中空球主要以SiO2、金属氧化物(如TiO2和SnO2等)及金属(金、银、钯和镍等)为主，而有关二元复合氧化物中空球合成的研究报道较少，制备球壳上具有介孔的中空球已有报道，但是，其得到的介孔常常不均一，因此，将中空球形材料、复合氧化物和均一介孔有效地结合起来将是非常有意义一项工作。

Preparation of Hollow Spheres of Si/Al Composite Oxide with Mesopores in the Shell Wall

Hollow spheres of Si/Al composite oxide with mesopores in the shell wall were prepared by combining O/W/O emulsion with sol-gel process. In this study, TEOS and aluminum isopropylate were used as silicon resource and aluminum resource, respectively. As an additive, PEG-20000 was added into the inorganic precursors. TEM and N₂ adsorption-desorption isotherms indicate the presence of mesopores with uniform pore size in the shell wall. The diameter, shell thickness and hollow structure property of the spheres were characterized by transmission polarized light microscopy and SEM. ²⁷Al MAS NMR spectrum shows that the coordinated number of the aluminum species is four. The influences on special morphology under different oil phase and reaction temperature were also investigated. The hollow spheres exhibit high thermal stability and can remain their intact spherical structures even after calcination at 550 ℃ for 6 h. This strategy can be extended to synthesize hollow spheres of other binary composite oxide with mesopores.