Microstructures, Optical Properties and Degradation Efficiency of Nitrogen-doped Titanium Dioxide to Automobile Exhaust

Abstract

To understand the influence of nitrogen (N) dopant on phase structure, morphology, optical property, photocatalytic degradation of TiO2 to automobile exhaust (AE) under visible light irradiation, the N-doped TiO2 was first prepared, and then X-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet-visible light diffuse reflectance spectra (UV-vis DRS) and photocatalytic degradation tests were conducted. Results indicated that only anatase phase was found in both pure TiO2 and N-doped TiO2, and the N doping improved the dispersity of TiO2. Also, the N doping increased the absorbance of TiO2 under UV and visible light, respectively. An obvious red shift was observed on UV-Vis DRS of pure and N-doped TiO2 samples, indicating that the spectral response range of TiO2 was expanded to visible light region, and the utilization efficiency of solar irradiance was increased. The prepared N-doped TiO2 nanoparticles with an N dopant content of 3.0% showed better optical properties. Finally, the N doping improved the photocatalytic activity of TiO2 to AE in the visible light region. Furthermore, the N-doped TiO2 presented lower degradation efficiency to CO than that to CO2 under visible light radiation. Thus, it is found that the degradation efficiency of TiO2 to AE can be increased by the N doping under visible light radiation.