Photocatalysis is the activity occurring when a light source interacts with the surface of semiconductor materials, the so called photocatalysts. During this process, there must be at least two simultaneous reactions occurring, oxidation from photogenerated holes, and reduction from photogenerated electrons. The photocatalyst itself should not undergo change and therefore a precise synchronisation of the two processes needs to take place. Fujishima and Honda first achieved an electrochemical photocatalysis of water at a semiconductor electrode in 1972. Later it was discovered that TiO2 aids in decomposing cyanide in water, rising interest towards the material’s environmental applications. TiO2 is suitable for photocatalysis for several reasons, some of which are its common availability, relatively low cost, and high chemical stability.
Photocatalysis can be successfully used in a real environment to decompose pollutants and enhance the quality of the atmospheric air. Photocatalysis can therefore be used in the building sector to improve indoor air quality.