Chemically grown TiO2 on glass with superior photocatalytic properties

•TiO2 and Degussa P25 thin films were grown on glass using the sol–gel technique.•The photocatalytic activity of the TiO2 samples was studied under UV-A illumination.•The degradation of stearic acid (SA) and methylene blue (MB) was investigated.•As-grown TiO2 is by far more photocatalytically active for SA compared to Degussa.

TiO2 anatase and Degussa (Enovik) P25 thin films were deposited on glass using the sol–gel technique at 600 and 80 °C, respectively. The structural, morphological and optical properties of the as-grown TiO2 films were studied against their thickness, for both of the experimental procedures described. Moreover, the photocatalytic activity of the TiO2 samples was investigated regarding the degradation of stearic acid and the decolorization of methylene blue, under UV-A light illumination. In specific, the 90 nm-thick (4×) Degussa P25 TiO2 films deposited on glass at 80 °C is by far the more photocatalytically active against methylene blue decolorization, reaching an apparent rate constant of 0.094 min−1, while the photocatalytic activity of the 110 nm-thick (4×) TiO2 thin films deposited on glass at 600 °C by sol–gel show the highest stearic acid disappearance rate, i.e., 9.46 × 10−8 mol/min (formal quantum efficiency = 10.02 × 10−3) at 15 min of UV-A light illumination.