ROS diffusion in the gas phase during the photocatalytic process
Résumé
Water and air purification by photocatalysis can be considered as a major challenge for the years to come.[1] Photocatalytic processes use a semiconductor photocatalyst, usually TiO2, as a slurry or deposited on a support. The semiconductor is exposed to near-UV light (<387 nm) and generates electron-hole pairs e-/h+ separated by the valence band (VB) and the conduction band (CB). In the presence of air and humidity, electrons (e-CB) and holes (h+ VB) induce reduction and oxidation processes producing reactive oxygenated species (ROS) such as OH•, HO2•, H2O2, and 1O2,[2,3] for example, through the following reactions