关键词: 中空球, 复合氧化物, 介孔, 热稳定性

Abstract: 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.

Key words: Hollow spheres, Si/Al composite oxide, Mesopores, Stability