Photocatalytic Activity of Nitrogen-Doped Titanium Dioxide Nanostructures Synthesized by DC Reactive Magnetron Sputtering Technique
Oday A. Hammadi, Firas J. Al-Maliki and Esraa A. Al-Oubidy
In this work, nitrogen-doped titanium dioxide (TiO2) nanostructures with homogeneous anatase structure were successfully synthesized by a dc reactive magnetron sputtering technique at different concentrations of nitrogen in the gas mixture (5%, 10% and 20%). The x-ray diffraction (XRD) and Fourier-transform infrared (FTIR) spectroscopy indicated that the TiO2 nanostructures were effectively doped with nitrogen dopants. Most dopants might bond to the TiO2 structures in the forms of Ti-O-N and O-Ti-N. A shift in the absorption edge to lower energies from 380 to 400nm and higher absorption in the visible light region were observed. The results of photodegradation of the organic pollutant (methylene blue) using visible light irradiation (λ>420nm) suggest that the TiO2 photocatalyst was highly improved after doped with nitrogen as compared with the undoped TiO2 photocatalyst. This improvement is attributed to the role of nitrogen dopants in narrowing the energy band gap of TiO2 from 3.20 to 2.92eV and hence extending the adsorption range to the visible region of electromagnetic spectrum.
Keywords: Titanium dioxide; Nanostructures; Photocatalysis; Magnetron sputtering