Photocatalytic activity of electrophoretically deposited (EPD) TiO₂ coatings

This paper describes the application of electrophoretic deposition for air pollution removal using anatase as a photoactive coating. In this study the anatase form of TiO2 has been applied to (i) fluorine-doped tin oxide coated glass; (ii) 304L stainless steel; and (iii) titanium substrates using isopropanol and acetylacetone based solutions at 20, 40, 60 and 80V. In order to increase the strength of the substrate-anatase interface without transforming the phase into rutile, samples were calcined at 450ºC for 2 hours. The resulting coatings were characterised by Raman spectroscopy, X-ray diffraction (XRD), non-contact optical profilometry and scanning electron microscopy (SEM). The photocatalytic activity of the deposited coatings were evaluated in the gas-phase for nitrogen dioxide (NO2) removal by electron ionisation mass spectrometry whilst irradiated by light of wavelength 376-387nm for 100 minutes. Anatase phase titania supported on a fluorine-doped tin oxide coated glass substrate showed the highest photoactivity for NO2 remediation. This was attributed to the formation of a three-dimensional nanostructure with properties determined by the deposition conditions. The work provides routes for the development of low-cost and large area photoactive coatings for pollution control.