Photocatalytic reaction is actually a reverse process of photosynthesis, which is the photolysis process that is the photocatalyst decomposes organic pollutants (formaldehyde, acetaldehyde, etc.) into carbon dioxide and water under the light. Photocatalyst coating is the product which capable play the fully effective photocatalytic effect, with air purification, anti-bacterial, sterilization, anti-mildew, deodorizing, anti-fouling, self-cleaning and so on.

 

Tungsten trioxide, the yellow tungsten oxide which has a lower band gap (2.4~2.8eV), can effectively use the visible light to produce photocatalysis, rather than only rely on the ultraviolet light. Because of its small adverse effects and cheap, tungsten trioxide can serve as a good photocatalyst used in building materials, etc., to play an excellent catalytic effect. Tungsten oxide has the relatively stable property in the air at room temperature; however, the provided products in the market have quite a large particle size, which result in the must milling dispersion treatment. However, after dispersion treatment, the photocatalytic activity will be reduced and the high activity of coating can not be obtained.

 

Metal tungsten by using a certain technique to burn or sublimate, thus to synthesize tungsten trioxide particles with a crystal structure, and then collected by using the ESP method (Electrical Dust Collection), then the tungsten oxide particles is dissolved in an alkaline aqueous solution to form a smaller particles, finally, we obtain a tungsten trioxide photocatalyst coating by adding a binder. In addition, after the combustion of particulates heat treatment, the high and stable photocatalyst can be obtained. It is worth mentioning that the amount of binder will also affect the activity of photocatalyst coating, when it is less than 1%, as the film, its strength is obviously not enough; while, when the amount exceeds 10%, the photocatalytic activity will be reduced.

 

Uniformly coat the tungsten trioxide photocatalyst coating on a plate glass or other places, to sufficiently evaporate the solvent component then the transparent and excellent strength of the photocatalytic film will be formed, to play a role of air purifier, the self-cleaning ect..