纳米SiO_2空心球结构材料的制备与表征

Preparation and characterization of nano-silicious hollow spheres

利用溶胶-凝胶法制备出纳米SiO2空心球结构材料,并采用煅烧或萃取的方法除去表面活性剂,对各种样品的表面形貌、结构特征以及表面硅羟基总数等进行了研究。结果表明:原始样品分散均匀,具有统一的尺寸大小以及丰富的表面硅羟基。此外,煅烧能更有效的除去表面活性剂,而萃取能更多的保留硅墙壁上的Si-CH3。煅烧虽然会导致部分微孔的塌陷,但是会更大的提高样品的比表面积。同时,由于共生羟基向孤立羟基的转化以及Si-CH3在高温下的氧化反应而拥有了较之萃取样品更多的表面硅羟基。

Nano-silicious hollow spheres were synthesized by a mild sol-gel method and a calcination or extraction procedure was carried out to remove the surfactants. The morphology, structure and the amount of surface Si-OH were studied. The results showed that the as-made samples were well-dispread with uniform particle size and possessed high sur- face SbOH. Furthermore, the calcination procedure was more effective for the removal of surfactants, but the extraction procedure can retain more Si-CHa on the wall of silica. As for the calcination procedure, it is more effective for the removal of surfactants and it dan increase more BET surface area more than that of the extraction procedure in spite of the collapse of the micropores. Meanwhile, the cooperative effect of the transformation of H-bonded Si-OH to isolated Si-OH and the oxidation of Si CH3 to Si-OH made the calcinated samples possessed relatively higher amounts of surface Si-OH compared to the extracted.