A new metastable phase of needle-like nanocrystalline VO 2·H 2O and phase transformation

作者：Gui Z; Fan R; Chen X H; Wu Y C

来源：Journal of Solid State Chemistry, 2001, 157(2): 250-254.

DOI：10.1006/jssc.2000.9037

• Hydrothermal synthesis
• Novel phase
• Phase transformation
• VO 2· H 2O

Needle-like nanocrystalline VO 2· H 2O, crystallized in a new metastable phase with orthorhombic symmetry (a = 6.015, b = 4.642, and c = 3.763 Å), was synthesized by a long hydrothermal reaction from NH 4VO 3 and hydrazine. The structure and composition of these nanocrystallites were characterized by X-ray powder diffraction, transmission electron microscopy, selected area electron diffraction, infrared absorbency spectroscopy, and thermogravimetric analysis. The influence of chemical reaction conditions on the features of the final products was investigated, and the optimum conditions were found to be 170°C for 15 days with a N 2H 4 concentration of 8.0. Differential scanning calorimetry was conducted to study the phase transformation from as-prepared metastable VO 2·H 2O to the more stable (B)VO 2 and rutile-type VO 2.

• 出版日期2001
• 单位中国科学技术大学