Abstract:

Hollow mesoporous silica microspheres SiO₂-1 and SiO₂-2 were prepared by sol-gel and hydrothermal synthesis using dichloride-N, N'-bis (3-hydrorosin loxy-2-hydroxypropyl) tetramethylenediamine (DHRT) as template agent and ethyl orthosilicate as silicon source.SEM, TEM, FT-IR, XRD and nitrogen adsorption-desorption were used to characterize SiO₂-1 and SiO₂-2.The results showed that silicon dioxide microspheres with amorphous structure were successfully prepared by both methods; the agglomeration phenomenon between silica particles gradually disappeared with the increase of the amount of template agent (0.1-1 g); SiO₂-1 was mainly loose microsphere with patterns, and SiO₂-2 was hollow microsphere with the wall thickness of 80-85 nm.The average particle size distributions of SiO₂-1 and SiO₂-2 prepared with different template dosages (0.3-1 g) were 0.22-0.33 μm and 0.34-0.41 μm, respectively.The morphology and particle size of SiO₂-1-0.7 and SiO₂-2-0.7 prepared by two methods exhibited good morphology and low particle size, with specific surface area of 561.52 and 463.41 m²/g, cumulative pore volume of 0.35 and 0.42 m³/g, and average pore size of 2.56 and 3.66 nm, respectively.Zeta potential analysis showed that the formation of SiO₂ hollow mesoporous structure was mainly caused by the cooperative self-assembly process between the oligomer obtained by hydrolyzing polycondensation of ethyl orthosilicate and the template agent.

Key words: silica, microspheres, mesoporous, hollow