Superhydrophilicity and photocatalytic activity of sol–gel deposited nanosized titania thin films

Nanosized TiO 2 thin films with anatase structure were synthesized by a sol–gel dip coating method using TiCl 4-ethanol solution as a precursor. The resulting solution was aged between 0 up to 24 h and characterized by the X-ray diffraction, atomic force microscopy (AFM), and UV–vis photospectroscopy. The AFM reveals that aging time incites the grain growth of crystal in the TiO 2 films. The effect of aging time on morphology, photocatalytic, and superhydrophilic behavior of the films was also studied. It was found that there is an optimum aging time that photocatalytic and superhydrophilic yields reach a maximum, simultaneously. Photocatalytic and photo-wettability mechanisms follow two kinds of behaviors, depending on whether the aging time is less or more than a threshold value of around 1 h.