Study of the Efficiency of Visible-Light Photocatalytic Degradation of Basic Blue Adsorbed on Pure and Doped Mesoporous Titania Films

Transparent mesoporous titania films have been deposited on glass slides by a sol−gel procedure in the presence of Triton X-100 reverse micelles in cyclohexane. Benzothiazolium, 2-[[4-[ethyl(2-hydroxyethyl)-amino]phenyl]azo]-5-methoxy-3-methyl(T-4)-methoxysulfate (Basic Blue 41), has been adsorbed on these films from aqueous solutions, and the photodegradation of the dye by visible-light illumination has been monitored by absorption spectrophotometry. Film nanostructure has been optimized for maximum photodegradation efficiency by controlling the original reverse micellar composition, the ripening of the particles, and the thickness of the films. Films doped with silver ions, incorporated through the reverse-micellar route, are more efficient photocatalysts than pure titanium films and become even more efficient when they are treated with UV radiation. Films doped with ruthenium ions are less efficient for photocatalysis but when they are treated with UV radiation, they also become more efficient photocatalysts than pure titania films.