Photocatalytic oxidation of nitrogen oxides on N-F-doped titania thin films

Visible light activated nanostructured TiO2 with nitrogen and fluorine co-dopants were prepared by the surfactant assisted sal-gel method and immobilized on glass substrates by dip coating. The films were inserted inside a continuous flow photoreactor and examined for the photocatalytic oxidation of NO air pollutant with initial concentration of 200-800 ppbv. The modified catalysts exhibited significant photocatalytic activity under daylight illumination, with maximum percentage of NO removal equal to 24.2% and photooxidation rate up to 0.66 mu g m(-2) s(-1). The reaction rates increased proportionally to the incident light intensity whereas for the strongly absorbed UV light a deviation from linearity was observed. Mass balance during photooxidation was confirmed by determining the amount of NO3- product residues onto the photocatalyst surface. (C) 2013 Elsevier B.V. All rights reserved.