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.

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.

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 Then, the hazardous waste catalyst which has been replaced by the professional department can be centralized and the valuable metals such as tungsten, vanadium and titanium can be recovered efficiently and safely without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.

Tungsten hexafluoride is a colorless gas at room temperature and its density is the largest among known gases. WF6 has a relative molecular mass of 297.84, and its molecule has a symmetrical regular octahedral structure at room temperature and is diamagnetic. At present, the industry mainly adopts a method in which metal tungsten is directly reacted with fluorine gas or NF₃ to prepare WF₆, and the reaction is usually carried out at a temperature higher than 350 °C.

Phosphotungstic acid is an important catalyst in the petrochemical industry. Its traditional synthesis method is ether acid extraction. This traditional method uses a low boiling organic compound, diethyl ether, as a complex extractant. The boiling point of ether is 34.5 °C, which is extremely volatile. Therefore, there are defects in safety and environmental pollution in the process of conventional synthesis of phosphotungstic acid.

Graphene has special structure and excellent performance. Using graphene as catalyst support can reduce the recombination of photogenerated electron-hole pairs in titanium oxide and improve the photocatalytic performance of titanium oxide effectively. However, due to the forbidden bandwidth of titanium oxide, only the ultraviolet part of sunlight can be utilized.

Coarse-grained tungsten carbide is widely used in mining tools, stamping dies, oil drilling and production, hard surface materials and other fields because of its advantages of less structural defects, high microhardness and small micro-stress. At present, the main method of producing coarse-grained tungsten carbide is to obtain coarse-grained tungsten powder first, and then to obtain coarse-grained tungsten carbide powder by further high-temperature carbonization.

The global environmental pollution problem restricts the progress of human civilization. The photocatalytic degradation of environmental pollutants has attracted more and more attention because of its advantages such as low energy consumption, mild reaction conditions, simple operation and reducing secondary pollution.

Silver has the best thermal conductivity, excellent processability and high oxidation resistance among all metals, so silver is the most important and economical precious metal contact material, and plays an important role in the field of low voltage electrical contacts. But silver is too soft, poor resistance to fusion and corrosion, and polarity transfer will occur.

With the increasingly serious environmental pollution and energy crisis, photocatalytic technology has attracted the attention of the domestic and foreign scientific circles for its potential application in the field of environmental purification and new energy materials, as well as the advantages of high efficiency, economy and environmental protection in the treatment of environmental pollution.