Recently, with development of nano technology, nano material is commonly used in various field. WO3 as semi-conducting metal oxide, its excellent gas sensitivity and photosensitiveness become researching focus in and abroad.

Because tungsten carbide and platinum have many similarities in catalysis, tungsten carbide is widely used in catalyst field. Therefore, the preparation of Nanocrystalline Tungsten carbide is increasingly important.

The excessive use of fossil fuels has caused global temperatures to continue to rise, and the search for new clean energy is becoming imminent. Among the existing emerging energy sources, solar energy has received much attention as an inexhaustible and pollution-free energy source.

Tungsten vanadium titanium based SCR catalyst is widely used in China's thermal power plant pollution control catalyst. The effective time of the catalyst is 3 years. When the time comes, it needs to be replaced. Then, the hazardous waste catalyst which has been replaced by the professional department can be centralized and the valuable metals such as tungsten, vanadium and titanium can be recovered efficiently and safely without polluting the environment.