N-TiO2 Photocatalysts highly active under visible irradiation for NOX abatementand 2-propanol oxidation

N-doped TiO2 powders were prepared by two different sol–gel methods. Samples were characterisedby X-ray diffraction (XRD), BET specific surface area measurements (SSA), scanning electron microscopy(SEM), diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) and Electron ParamagneticResonance (EPR). XPS measurements revealed a signal at 400 eV assignable to nitrogen in theform of Ti N O. EPR signals are attributed to molecular NO trapped with cavities/defects possibly interactingwith oxygen vacancies. The photocatalytic activity under UV and visible light was determinedfollowing the abatement of NOx and the photodegradation of 2-propanol in gas–solid systems. N-dopedTiO2 showed a higher activity compared with the pristine commercial and home prepared samplesunder visible light irradiation. A good photoactivity in the abatement of both NOx and 2-propanol isalso observed for mechanical dispersions of N-TiO2 in CaCO3 serving as a model in view of perspectiveapplication in photocatalytically active construction and architectural materials.