The photocatalyst is a low cost and high efficiency, the implementation of environmental management method is convenient, use light sunlight or other sources of air pollutants, the water and soil environment were non-toxic degradation and purification, quality and chemical properties will not change itself.

Coarse grained tungsten carbide has many advantages, such as good crystalline property, few structural defects, large subgrain size, high microhardness, small strain and plasticity. It can meet the needs of cemented carbide for mining, petroleum and heavy machinery industries. The key point of preparing high performance coarse grained cemented carbide is coarse-grained, homogeneous and well crystallized tungsten carbide powder.

Tungsten oxide film is a kind of functional material which has been widely studied. It has excellent shortwave transmittance, the band gap easily through doping regulated by ion implantation and ultraviolet photon irradiation, gas adsorption, the optical and electrical properties will produce significant changes in optical glass, flat panel display, photoelectric conversion, electrochromic, photochromic and has wide application prospect.

Because non-stoichiometric tungsten oxide has a certain reduction ability, precious metal particles can be directly deposited on the surface of tungsten oxide by utilizing the weak reducing ability of low-valent tungsten oxide and the reaction of reducing precious metal salt solution by in situ reduction.

Tungsten oxide quantum effect refers to the tungsten oxide particle size down to a certain value, the Fermi level near the electronic energy level from quasi-continuous to discrete energy levels or widen the gap phenomenon. When the energy level changes more than thermal energy, light energy and electromagnetic energy, the magnetic, optical, acoustic, thermal, electrical and superconducting properties of tungsten oxide particles are significantly different from those of conventional materials.

Tungsten carbide is a compound composed of tungsten and carbon. It is mainly used in the production of cemented carbide. At present, the way to produce tungsten carbide powder is the two step method, that is, first we use hydrogen to reduce tungsten oxide to tungsten powder, the tungsten powder is then carbonized and carbonized into tungsten carbide at high temperature. But this method is not easy to produce ultrafine tungsten carbide powder, not to mention the production of ultrafine particles of tungsten carbide - metal cobalt composite powder.

The surface effect means that when the tungsten oxide particles are in the small size range of 1-100 nm, as the diameter of the tungsten oxide particles becomes smaller, the number of atoms on the surface of the nano particles is rapidly increased.

Defective tungsten oxide nanomaterials have drawn wide attention in the tungsten products industry because of their unique structural properties and excellent properties. The use of traditional solvothermal method can be prepared with defective tungsten oxide nanomaterials. Defective tungsten oxide nanomaterials synthesis method is as follows:

Unlike the stoichiometric tungsten oxide color, the defective tungsten oxide nanomaterials are light green or blue with an extra broadband absorption between 400 and 700 nm. This increased absorption peak is due to the presence of oxygen vacancies leading to a new band in the conduction band.

In the prior art, the preparation of ammonium paratungstate industrial process from tungsten mineral raw materials by caustic soda or soda decomposition to obtain crude sodium tungstate solution; purification by solution ion exchange or solvent extraction transformation to obtain the pure ammonium tungstate solution; then through evaporation and crystallization, APT products.