Ammonium Metatungstate Evaporative Reduction Method Prepared Violet Tungsten

Metal oxide semiconductor materials have excellent properties. How to reduce the production cost of semiconductor materials and increase the conversion rate of energy has become a hot topic of research.

As a semiconductor material, tungsten oxide is widely used in photoelectrochemistry. The monoclinic violet tungsten has the maximum oxygen defect structure, compared with yellow tungsten (WO₃) and blue tungsten (WO_2.9), violet tungsten has special surface structure and chemical activity. It is suitable for the production of ultrafine particles of tungsten powder and various kinds of tungsten compounds. violet tungsten can be applied to biomedicine as a carrier for cancer cell drugs, intelligent insulation, and can also be applied to photocatalytic degradation of organic pollutants.

Some scholars have proposed the ammonium metatungstate evaporative method which is different from the traditional method, and the general process is as follows:

1. According to the reaction measurement ratio, take ammonium metatungstate 0.01mol, ammonium nitrate 0.24mol, thiourea 0.05mol.

2. Solution preparation: the raw material was proportionally mixed into solution, mixed evenly, the mole ratio of ammonium nitrate to ammonium metatungstate was 12~36, the mole ratio of the auxiliary agent to ammonium metatungstate was 5~15.

3. The solution was heated at constant temperature of 200 degrees, evaporated and concentrated to form colloidal substances, and then decomposed and produced a lot of gas. Then, nano needle-shape violet tungsten powder was obtained through oxidation-reduction reaction.

The ammonium metatungstate evaporative reduction method is easy to be produced in scale. The needle shaped violet tungsten has fine grain size, large specific surface area, large surface activity and excellent performance.

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