At first glance, it looks like nothing more than a simple, fine white powder. But appearances can be deceiving. Titanium dioxide (TiO2) is a very unique and interesting material. Even today it continues to be at the heart of photocatalysis research. Most prominent among them is the discovery that when exposed to light, TiO2 can split water into oxygen and hydrogen.
Two principle discoveries were found out that sunlight in combination with TiO2 oxidizes water—breaking it into to oxygen and hydrogen—and later that TiO2 has a strong affinity for water, a characteristic technically known as superhydrophilicity.
TiO2 has been instrumental in the development of air and water purification technologies as well as self-cleaning, anti-fogging and anti-staining applications.
The most pervasive and perhaps the most straightforward example of TiO2 applications is that of self-cleaning buildings. Tiles and other surfaces coated with TiO2 stay clean thanks to the properties of the substance. Sunlight causes oxidation that breaks down grime while the superhydrophilicity of the substances causes the water to spread, washing surfaces clean. Air purifiers and anti-fog mirrors are two other popular applications.
TiO2 can break down water, kill bacteria, and deodorize by getting rid of odors like that of tobacco or pets. It is truly an incredible substance.
Currently, among photocatalysts, TiO2 is the most efficient in terms of photoactivity, stability and is also the least expensive.
TiO2 has been shown to kill not only bacteria, but also viruses and cancer, he says. At the same time, indoor uses of TiO2 could greatly improve quality of life but also pose a particular challenge.