Novel sol-gel synthesis of Al/N co-doped TiO2 nanoparticles and their structural, optical and photocatalytic properties

In the present investigation novel Aluminium/Nitrogen (Al/N)-codoped TiO2 nanoparticles (NPs) have been prepared via sol-gel route under mild conditions. The structural, optical, morphological and compositional properties of all the prepared samples have been characterized by X-Ray Diffraction (XRD), X-Ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscope, Transmission Electron Microscopy, UV-Vis spectroscopy (UV-Vis) and Photoluminescence Spectroscopy (PL). XRD results reveal that the doping of Al in TiO2 nanostructure hinders its crystal growth and stabilizes the crystal structure. XPS result confirms the successful incorporation of Al and N in TiO2 structure. UV-Vis measurement shows a distinct alteration in the optical properties of TiO2 resulting in red shift i.e. lower band gap values relative to undoped TiO2 NPs. Moreover, PL spectra reveal prolonged electron-hole pair lifetime for efficient photocatalytic performance. Thus, Al/N co-doped samples exhibit enhanced absorption, retarded charge carrier recombination and hence excellent photocatalytic activity for degradation of methylene blue (MB) solution under visible light irradiation. A sample doped with 2wt% Al/N-doped TiO2 NPs shows best photocatalytic activity among all other samples.