Titanium dioxide (TiO₂) or titania is a photocatalyst and has been regarded as a promising material in waste abatement since it was discovered that water could be decomposed on titania under ultraviolet (UV) irradiation. In this study, anatase sols are prepared at low temperature by hydrolysis and condensations of titanium tetraisopropoxide. Titania thin films are produced on glass substrates from colloidal sols by spin coating process. The superhydrophilic and photocatalytic properties of the titania thin films are evaluated.

XRD patterns shows sharp anatase peak of titania, confirming presence of crystalline anatase phase. The absorption of UV light mainly results from the promotion 3d electrons in the crystal field. Typical TEM micrographs of titania calcined at 450°C for 3 hours shows the anatase crystallites of about 17-20 nm in diameter, which is in agreement with the size of the crystallites determined by XRD analysis. In HRTEM image, lattice fringes corresponding to (101) planes of anatase phase was observed. Figure 1 shows the comparison between uncoated and coated glass when dry and with water droplet. The titania coated glass is superhydrophilic with contact angle less than 3° (water spreads out on the glass surface). Photocatalytic activity of anatase titania thin films was confirmed by measuring the salicylic acid degradation under UV illumination. The study shows encouraging preliminary results which warrant further investigation of nanotitania as coating material for self-cleaning surface.