Preparation and structure characteristics of nano-Bi2O3 powders with mixed crystal structure

The nano-Bi2O3 powders were prepared by a chemical precipitation method with Bi(NO3)3, HNO3 and NaOH as reactants. The structural characteristics and morphology of nano-Bi2O3 powders were investigated by X-ray diffraction and transmission electron microscopy, respectively. The results show that under the optimum condition that 300g/L Bi(NO3)3 reacts at 90℃ for 2 h, the Bi203 powders with 60 nm on the average and 99.5% in purity are obtained. The prepared nano-Bi2O3 powders contain a mixed crystal structure of monoclinic and triclinic instead of traditional structure of monoclinic α-Bi2O3. And the mixed crystal structure is stable in air. The reason for the appearance of the mixed crystal structure may be that the ionic radius ratio of Bi^3 to O^2- changes easily during the formation of nano-Bi2O3 particles by a chemical precipitation method.

Preparation and structure characteristics of nano-Bi2O3 powders with mixed crystal structure

The nano-Bi₂O₃ powders were prepared by a chemical precipitation method with Bi(NO₃)₃, HNO₃ and NaOH as reactants. The structural characteristics and morphology of nano-Bi₂O₃ powders were investigated by X-ray diffraction and transmission electron microscopy, respectively. The results show that under the optimum condition that 300 g/L Bi(NO₃)₃ reacts at 90°C for 2 h, the Bi₂O₃ powders with 60 nm on the average and 99.5% in purity are obtained. The prepared nano-Bi₂O₃ powders contain a mixed crystal structure of monoclinic and triclinic instead of traditional structure of monoclinic α-Bi₂O₃. And the mixed crystal structure is stable in air. The reason for the appearance of the mixed crystal structure may be that the ionic radius ratio of Bi³⁺ to O²⁻ changes easily during the formation of nano-Bi₂O₃ particles by a chemical precipitation method. Foundation item: Project (2003AA305820) supported by the National High Technology Research Plan of China