Nanocrystalline TiO2 based films onto fibers for photocatalytic degradation of organic dye in aqueous solution

Nanocrystalline titania (TiO2) synthesized via sol-gel, by using an alkoxide precursor were deposited onto
commercially available silica and alumina fibers, namely E-Glass and Nextel 650, respectively. Different
processing conditions and material preparation parameters, such as amount of TiO2, film composition and
annealing temperature were tested in order to obtain nanocrystalline TiO2 with different morphological
and structural characteristics. The materials were characterized by scanning electron microscopy (SEM),
X-ray diffraction (XRD), and the Brunauer, Emmett, and Teller (BET) surface area measurements. The
photocatalytic activity of the obtained coated fibers was investigated by monitoring the degradation
of a model molecule, an azo dye (Methyl Red), under UV irradiation in aqueous solution. The detected
photocatalytic performance of the sol-gel derived nanocrystalline TiO2 was explained on the basis of
mechanism associated to the photocatalytic decomposition of organic molecules using semiconductor
oxides and accounted for the structural and morphological characteristics of the TiO2 based coating. The
materials with the most suited characteristics for photocatalysis were used to scale up the deposition
onto a larger sample of fiber and then tested in a photocatalytic reactor. A commercially available TiO2
standard material (TiO2 P25 Degussa) was used as reference, in order to ultimately assess the viability of
the coating process for real application.