Preparation of SiO2 Encapsulated ZnO Nanopowders by Sol-Gel Method
The shell-core structures of SiO2/ZnO nanopowders were obtained by simple two-step technique based on low-temperature crystallization from liquid phase. The influence of molar ratio of SiO2/ZnO in the reaction mixture on the morphology of obtained SiO2/ZnO nanopowders was studied. Crystalline structure of SiO2/ZnO nanocrystals obtained was proofed by the X-ray diffraction data. The average diameter of SiO2/ZnO nanocrystals was about 80~100nm according to FSEM and TEM data. It is shown that SiO2 components on the surface prevent the thermal interfusion of ZnO particles. Morphology and diameter of raw ZnO, SiO2/ZnO nanopowders prepared with molar ratio of SiO2/ZnO 0.1, 0.2, and 0.5 were almost same. When molar ratio of SiO2/ZnO was 0.5, ZnO core was coated with SiO2, and the thickness of shell was about 10nm. At the same time, SiO2 nanocrystals also formed the islands structure.
Cheng Zhang and Jin Hu
Y. X. Wang et al., "Preparation of SiO2 Encapsulated ZnO Nanopowders by Sol-Gel Method", Advanced Materials Research, Vol. 412, pp. 13-16, 2012