Efficient removal of 2-chlorophenol from aqueous solution using TiO 2 thin films/alumina disc as photocatalyst by pulsed laser deposition

Pulsed laser deposition facilitates the epitaxial deposition and growth of TiO 2 at low temperature on hot substrate. In this study, nanosized nitrogen-doped TiO 2 thin films were deposited on fabricated alumina disc-shaped and glass substrates. Textural properties of the fabricated disc and alumina disc-supported TiO 2 were investigated using N 2 adsorption–desorption isotherms, field emission scanning electron microscopy (FESEM), X-ray diffraction and Fourier transform infrared (FTIR) spectroscopy. FESEM showed the presence of single crystals of TiO 2 on the alumina disc. FTIR showed the presence of octahedral TiO 2 and different hydroxyl groups on the surface which is responsible for the photoactivity and also showed the functional groups adsorbed on the catalyst surface after the photocatalytic degradation. The concentration of 2-chlorophenol and the photo-redox intermediate products as a function of irradiation time was determined. The concentration of the produced chloride ion during the photocatalytic degradation was determined by an ion chromatography. The results showed that the photocatalytic activity of the catalyst decreased upon cycling. The obtained results were compared with nanostructured TiO 2 supported on glass substrate. Higher efficiency of 100% degradation was achieved for TiO 2 /Al 2 O 3 catalyst, whereas about 70% degradation of 2-CP was achieved using TiO 2 /glass. Different photointermediates of 2-CP degradation have been identified for each cycle. The difference of intermediates is supported by the adsorbed fragments on the catalyst surface.