Abstract
One of the basic tenets of photochemistry is that the driving force in a photochemical reaction is the very large quantized energy of the photon. This means that even an extremely weak source of excitation light could induce chemical reactions. We tried to utilize this energy of photon and discovered that materials coated with photoactive TiO2 film exhibit sterilizing and self-cleaning functions photochemically under ordinary indoor and outdoor UV illumination. These effects are based on the photo-induced decomposition and hydrophilic conversion reactions on TiO2 surfaces. In order to maintain a clean environment, we often use chemicals such as deodorants, germicides, detergents, etc. Conversely, the present TiO2 materials make it possible to maintain clean conditions without using any chemicals, but using only light and water. We believe that TiO2 photocatalysis using very low-intensity light will open a new avenue in environmental science.
