Technology  >> Photocatalyst  >> Hydrophilic Property             Hydrophilic Property                     When  Nano TiO2  absorbs radiation from light  and have excess energy to promote the electron to the conduction band, it will generate electron-hole pairs .                         The holes oxidize the  O2- Anions and the electrons tend to reduce Ti(IV) cation to Ti(III) state. In this process, oxygen (O2)  atoms are ejected,  creating oxygen vacancies. Water molecules can then occupy these oxygen vacancies,  producing OH groups, which tend to make the surface hydrophilic.