Tungsten oxide (WO₃) with low dimensional nanostructure is a kind of important functional material, especially the WO₃ nanometer single crystal. Since it has good gas sensitive, light corrosion resistance, electrochromism, gasochromism, thermochromism and photochromism and other properties, it is widely used in gas sensor, visible light catalyst, flat-panel display, and other fields. The raw materials of tungsten trioxide nanometer single crystal are soluble tungstate, WO₃ceramics material, metal tungsten and tungsten hexachloride, with the manufacturing method of ion exchange, hydrothermal, gas phase deposition and sol-gel method, etc. 

 

A study has put forward a method for preparing WO₃ nanometer single crystal from the raw material of ammonium metatungstate (AMT), and this process has the advantages of simple and feasible, suitable for industrialized mass production of nanoscale level and size controllable of WO₃ single crystal, with the steps as follows: 

1. Dissolve the polyvinyl alcohol (PVA) or polyvinylpyrrolidone (PVP) in distilled water to get the polymer solution with the quality concentration of 10-20%; 

2. Dissolve the ammonium metatungstate in the distilled water according to the ratio of quality: volume of 1g: 1ml, to get the transparent AMT solution; 

3. Uniformly mix the polymer solution and AMT solution obtained respectively from step 1 and 2 according to the volume ratio of 10:1, According to the, will get the polymer solution of step 1 and step 2 partial mixing ammonium tungstate solution, and then let stand until frothy disappear get mixed solution; 

4. Pour the mixture into burning ship, and turn it into the muffle furnace in 550 ~ 900 ° C to calcine for 4 ~ 8 hours, with the heating rate of 10°C/min, and finally get the yellow powdery WO₃ nanometer single crystal along with natural cooling by the furnace.

 

Ammonium metatungstate (AMT) is a kind of water-soluble crystallization of white or yellowish powder, due to its very large solubility in water, it is widely used in the industry, such as producing metal tungsten, tungsten carbide powder and other tungsten products; moreover, AMT can be used in fireproof fabric, ceramic industry and all kinds of petrochemical catalysts due to its special properties.