Modification of the Optical and Electronic Properties of TiO₂ By N Anion-Doping for Augmentation of the Visible Light Assisted Photocatalytic Performance

Abstract

In this work, a nitrogen-doped anatase TiO₂ nanocrystal is prepared by a modified sol-gel preparation method using the nonionic surfactant (polyoxyethylene sorbitan monooleate) as a structural controller and a soft template. The as-prepared samples are characterized by X-ray diffraction, Raman spectroscopy, UVVis diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy techniques. Then the photocatalytic activity of these samples is assessed by the photocatalytic oxidation of phenol under visible light irradiation. The phenol concentration is measured using a UV-Vis spectrometer. Experimental results show that N-doping leads to an excellent visible light photocatalytic activity of the TiO₂ nanocatalyst. Furthermore, the formation energy and electronic structure of pure and N-doped anatase TiO₂ are described by density functional theory (DFT) calculations. It is found that N-doping narrowed the band gap of bare TiO₂, which leads to an excellent visible light photocatalytic activity of N–TiO₂ nanocatalysts. Therefore, the prepared N–TiO₂ photocatalyst is expected to find the use in organic pollutant degradation under solar light illumination.