Preparation and Characterization of Cu3V2O7(OH)2•2H2O Hollow Spheres from Na2V6O16•3H2O Nanobelts

Monoclinic Cu3V2O7(OH)(2)center dot 2H(2)O (Copper polyvanadate) hollow spheres were prepared with Na2V6O16 center dot 3H(2)O nanobefts as V-precursor by hydrothermal method. The purity and structure of the products were characterized by X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, thermogravimetric analysis (TGA) and X-ray photoclecton spectroscopy (XPS). The morphology and size were observed by scanning electron microscopy (SEM). We found that the Kagome staircase-structural copper polyvanadate hollow spheres with an average diameter of 7 mu m could be easily synthesized via the reaction of Na(2)V(6)O(16 center dot)3H(2)O nanobelts with sufficient copper sulfate. The dielectric property of the copper polyvanadate demonstrates that dielectric loss hardly changes when the frequency of applied electric field is higher than 100 kHz. The formation process of the hollow spheres is discussed in detail by the observation of a series of products prepared for different reaction time.