Tungsten trioxide nanopowder applying for thermal insulation paper may be synthesized by hydrothermal method using Na2WO4 and HCl as raw materials. And the influence of different hydrothermal reaction temperatures on the structure, morphology and photochromic properties of tungsten trioxide are analyzed.
Influence of Hydrothermal Temperature on Synthesis of Tungsten Trioxide
The following figure shows the XRD pattern of WO3 powder prepared at different hydrothermal temperature when the pH value of the reaction system is 1.0. In the figure, e: T=80°C; f: T=100°C; a: T=120°C; h: T=140°C; i: T=160°C; j: T=180°C. As can be seen from the figure, the hydrothermal temperature has a significant influence on the crystal structure, crystal grain size, and degree of crystallinity of the synthesized product. By analyzing the diffraction peaks and peak intensities of the XRD patterns of the products synthesized at different reaction temperatures, the synthesized products contain hexagonal tungsten trioxide. If the reaction temperature is higher than 160°C, the tungsten trioxide transforms from hexagonal phase to cubic phase. But, the conversion at 180°C is not complete, and the hexagonal tungsten trioxide is still in the product.
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Tungsten Trioxide Nanopowder Applied for Thermal Insulation Paper
