Investigations on the photocatalytic activity of sol–gel derived plain and Fe3+/Nb5+-doped titania coatings on glass substrates

Plain and doped (Fe3+ and Nb5+) titania coatings were deposited by dip coating on soda lime glass substrates using titania sol synthesized by sol–gel route in combination with commercial nanoparticle dispersions. The dopant concentrations were fixed at 0.07 wt% and the coatings heat treated at 400 °C were characterized with respect to their thickness, phase composition, hydrophilicity/hydrophobicity and microstructure. Photocatalytic activity testing was carried out on the coatings by following up the degradation of methylene blue dye for up to 4 h at 1 h time intervals after exposure to sunlight. The effect of a trivalent and pentavalent doping of Ti4+ sites on photocatalytic activity of TiO2 was investigated.