Novel sol–gel preparation of V-TiO2 films for the photocatalytic oxidation of ethanol in air

• Vanadium-TiO2 sols were synthesized by a novel non-aqueous sol–gel method.
• The undoped TiO2 catalyst performed better than the V-doped samples.
• The better performance of bare TiO2 is due to nitrogen trace (confirmed by XPS).
• In the co-doped system the lower the dopant concentration the higher the activity.
• The higher activity is due to the lower recombination of the charges photogenerated.

A series of vanadium-doped TiO2 catalysts were synthesized by a novel non-aqueous sol–gel method. Ammonium metavanadate was used as dopant source and diethanolamine as chelating agent. The effect on the crystallization, optical properties and photocatalytic activity of the doped TiO2 films was investigated. Furthermore, to identify the effective composition of the samples, they were characterized by X-ray photoelectron spectroscopy (XPS). The characterization reveals the presence of some N originating from the chelating agent in all samples and confirms V incorporation into the doped samples. Undoped TiO2 shows high activity under UV + visible and only visible illumination due to the presence of nitrogen. Among the V doped catalysts, the 1 wt.% doped film exhibited the highest photocatalytic activity. This synthetic method leads to V doped titania catalysts which performed much better and in which vanadium ions are more homogeneously distributed than V doped samples synthesized using V2O5 and vanadium alkoxide as V dopant sources. The V + N doped TiO2 films yield higher activity than single V doped films, but lower than the single N doped TiO2 film. The co-doping of films requires tuning of concentrations to optimize the photocatalytic activity.