Abstract
Cu and N-doped TiO2 photocatalysts were synthesized from titanium (IV) isopropoxide via a microwave-assisted sol-gel method. The synthesized materials were characterized by X-ray diffraction, UV-vis diffuse reflectance, photoluminescence (PL) spectroscopy, SEM, TEM, FT-IR, Raman spectroscopy, photocurrent measurement technique, and nitrogen adsorption–desorption isotherms. Raman spectra and XRD showed an anatase phase structure. The SEM and TEM images revealed the formation of an almost spheroid mono disperse TiO2 with particle sizes in the range of 9-17nm. Analysis of N2 isotherm measurements showed that all investigated TiO2 samples have mesoporous structures with high surface areas. The optical absorption edge for the doped TiO2 was significantly shifted to the visible light region. The photocurrent and photocatalytic activity of pure and doped TiO2 were evaluated with the degradation of methyl orange (MO) and methylene blue (MB) solution under both UV and visible light illumination. The doped TiO2 nanoparticles exhibit higher catalytic activity under each of visible light and UV irradiation in contrast to pure TiO2. The photocatalytic activity and photocurrent ability of TiO2 have been enhanced by doping of the titania in the following order: (Cu, N) - codoped TiO2>N-doped TiO2>Cu-doped TiO2>TiO2. COD result for (Cu, N)-codoped TiO2 reveals ∼92% mineralization of the MO dye on six h of visible light irradiation.