Influence of N doping on structural and photocatalytic properties of hydrothermally synthesized TiO2/carbon composites

Abstract

N-doped TiO2/carbon composites (TiO2/CN) with different nitrogen content, were obtained starting from titanium isopropoxide and glucose, and by varying the amount of melamine, added to starting reaction mixture. For comparison, an undoped sample (TiO2/C) was also prepared. Structural and surface characteristics were determined through scanning electron microscopy, thermogravimetric analysis, elemental analysis, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction and nitrogen adsorption–desorption isotherms. The photocatalytic activity of TiO2/CN composites was examined via photocatalytic degradation of methylene blue and multiclass pharmaceuticals from water solution. It was found that N doping of TiO2/carbon composites induced changes in structural and surface characteristics of TiO2/CN composites, improving their adsorption, but decreasing photocatalytic efficiency. Nevertheless, TiO2/CN0.05 composite obtained by the hydrothermal synthesis in the presence of glucose and 0.05 g melamine showed the highest efficiency for removing selected pharmaceuticals and methylene blue from aqueous solutions through the combined processes of adsorption in the dark, and photocatalytic degradation under UV and visible irradiation.