Two-thirds of Tokyo’s buildings, as well as other high -profile constructions around the world, now incorporate ‘self-cleaning’ window glass coated with a 10 -20 nm layer of titanium dioxide (TiO2), noted Akira Fijishime (Kanagawa Academy of Science and Technology, Japan) at “Nanotechnology for Sustainable Economy European and International Forum on Nanotechnology” (Prague, Czech Republic, June 2-5, 2009). TiO2 promotes the decomposition of pollutants such as NOx, and acts as a wetting agent to facilitate the washing action of rainfall. Other applications of this versatile material are in fog -resistant mirrors and self –disinfecting coatings on tiles used in hospitals, as well as in air - and water-purification. In Japan alone, the market size is estimated at around $1.1 billion (€750 million), according to conference proceedings.
The market in Europe for TiO2 coatings remains slow due to delays in the introduction of relevant international standards, according to a conference report. Self-cleaning glass coatings are available from a number of manufacturers in the U.S. Titanium dioxide is a safe substance, which is harmless to humans. It has been approved by the food-testing laboratory of the United States Food and Drug Administration (FDA).
Photocatalytic materials have massive commercial potential, e.g. in the construction and environmental sectors. Studies over many years have focused mainly on titanium dioxide (TiO2) because of its stability, commercial availability and ecological safety. When the photo-catalyst, TiO2, captures ultraviolet light it forms activated oxygen from water or oxygen in the air. Because of its catalytic nature photo-catalyst properties are not consumed during this chemical reaction. The treated surface regenerates its photo-catalytic effect by reacting with oxygen in the air. TiO2 actively decompose bacteria, biological and chemical pollutants, toxins, bad odors, mold and other fungi.