A photocatalyst is a material that functions as a catalyst (alters the rate of a chemical reaction) when exposed to light.
It shows "decomposing ability" and "hydrophilic properties" upon exposure to ultraviolet light.

*Decomposing Ability

As it can decompose various organic substances, it removes dirt and odors, as well as reduces the growth of germs.

*Hydrophilic Properties

The surface easily becomes wet, so when rain water falls on it, the water goes under the dirt and suspends it, and as a result, the dirt can be washed off. There is also an anti-fogging effect.

Usage of Photocatalyst Titanium Dioxide

Photocatalyst is used in products of various fields depending upon the effect, as shown in the figure below.