Bismuth tungstate is a new type of visible light catalyst. Its band gap is small, its absorption light is strong and easy to be modified. Co₃O₄ and Bi₂WO₆ are combined into a composite photocatalyst of bismuth cobalt tungstate with a hydrothermal synthesis method, and the photocatalytic performance is greatly improved. The process of synthesis is:

Bismuth tungstate (Bi₂WO₆) photocatalyst is considered to be a potential excellent visible light photocatalyst because of its unique electronic structure, excellent visible light absorbability and high organic degradation ability. At present, the preparation methods of bismuth tungstate are mainly concentrated in coprecipitation and hydrothermal methods.

Bismuth tungstate is a typical mixed metal oxide, which has a series of advantages such as absorbable visible light, low cost and good stability. It has been widely studied in photocatalysis. However, the photocatalytic activity of bismuth tungstate crystals is low due to the high photoelectron and hole recombination rate in the bismuth tungstate crystal. Therefore, by modifying the structure of bismuth tungstate, reducing the recombination of photo generated electrons and holes, it is of great significance for improving the efficiency of photolysis of water to produce oxygen.

At present, due to the increasingly serious energy shortage and environmental pollution problems of the rapid development of industry, clean energy and demand to the efficient use of solar energy clean technology is getting more and more urgent, and the photocatalytic technology for its environmental protection and energy saving, mild reaction conditions and no two pollution has showed good application prospect, in many photocatalytic the material, Bi₂WO₆ is currently the research more, a catalyst of visible light photocatalytic activity of light is also good.

Bismuth tungstate (Bi₂WO₆) is a kind of photocatalytic material with visible light response, because of its suitable band gap, relatively high light stability, unique crystal structure and green non-toxic properties, has been widely used in photocatalytic field, such as photocatalytic water splitting, selective light machine synthesis and purification and so on air or water organic pollutants.

As a kind of commonly used methyl orange dye, in its use during 10% ~ 20% were discharged into the water environment, and the toxicity of wastewater containing methyl orange, contain carcinogenic, mutagenic, teratogenic substances; high chroma, inhibition of photosynthesis in aquatic system; high COD value, will lead to water eutrophication.

The overuse of fossil fuels has resulted in the continuous rise of global temperature. Finding new clean energy has become imminent. In the existing emerging energy sources, solar energy has attracted much attention as an inexhaustible and pollution-free energy. Recently, there have been reports from foreign countries that a scientific research team has successfully implemented water hydrogen by using photocatalysis.

Ammonium metatungstate is an important tungsten intermediate compound. It is mainly used for the manufacture of tungsten carbide and other tungsten compounds in the petrochemical industry. It is an important precursor for the production of tungsten carbide catalysts. Tungsten carbide is widely used because of its catalytic activity similar to that of platinum metal in catalytic reactions such as alkane dehydrogenation to olefins, olefin isomerization, and hydrogenation reactions.