With special surface structure and oxygen defect structure, violet tungsten oxide can be modified by copper ions, so as to have better photocatalytic properties. Copper modified violet tungsten oxide, which has a high rate of solar energy utilization, is an efficient photocatalyst.

Violet tungsten oxide is powder with unique color between dark purple and pure purple. It is generally prepared by calcining ammonium paratungstate in a rotary furnace. The color of violet tungsten oxide differs from different preparation methods.

In order to extract tungsten from tungsten minerals, at present, China's tungsten metallurgy industry mostly adopts the alkaline smelting system. After high-pressure leaching of sodium tungstate solution, ion exchange is carried out and apt is extracted by evaporation crystallization. At present, there are two outstanding problems in this process that have not been effectively solved: first, the waste water discharge is large. Second, the discharge of waste salt is large.

Among the many vanadium oxides, vanadium dioxide is different because of its rapid and sudden phase transition. Its phase transition temperature is 68 ℃, which can change reversibly from low temperature monoclinic system to high temperature tetragonal system, making its physical properties such as resistivity, optical transmittance and magnetic conductivity change greatly. This characteristic makes it have a great prospect in intelligent switch, electronic device and photoelectric equipment. The results show that tungsten can effectively reduce the phase transition temperature of vanadium dioxide, and copper can improve the conductivity of vanadium dioxide.

Silica bismuth is a typical semiconductor material. Through the action of light, electrons are excited by light to transition and leave corresponding holes, forming electron hole pairs. These photo generated electron hole pairs have strong redox ability and are easy to react with organics and polymers. Due to the narrow band gap, they respond well to visible light;

With the development of science and technology, toxic organic pollutants from industrial and agricultural production seriously threaten the environment and human health. It is of great significance to seek a new and efficient environmental treatment technology. Photocatalytic technology has become a new environmental treatment technology with important application prospect because of its advantages of energy saving, high efficiency, complete pollutant degradation and no secondary pollution.

Heteropolyacids have been developed for more than 100 years, and the research contents have been gradually extended to material chemistry, electrochemistry, catalytic chemistry, photochemistry, surface science, medicine and other fields. Therefore, heteropolyacids show high catalytic activity and selectivity for various organic reactions.

In architecture, through glass doors and windows is the main source of energy loss. In China, the energy loss through glass doors and windows can be as high as 40% - 50% of the total building energy consumption. At the same time, especially in today's society, the large-scale use of glass wall aggravates the loss of building energy consumption.

Silver nickel electrical contact has been widely used in various low-voltage electrical appliances because of its good thermal conductivity, low and stable contact resistance, excellent processing performance and other advantages. However, due to its poor anti fusion welding performance, the application range of silver nickel electrical contact is affected.

Cathode materials have been the bottleneck to improve the performance and reduce the cost of lithium-ion batteries. Lithium iron phosphate is the first choice of cathode materials for modern commercial lithium-ion batteries because of its low price, high energy density, long life and good safety. However, the low electronic conductivity of lithium iron phosphate seriously hinders its application in the field of power and energy storage batteries.