Nitrogen-doped TiO2 nanoparticles by using EDTA as nitrogen source and soft template: Simple preparation, mesoporous structure, and photocatalytic activity under visible light

A new way to dope TiO2 nanoparticles by using ethylene-diaminetetraacetic acid (EDTA) as N source is introduced here. The nitrogen doped titanium oxide was successfully synthesized through an EDTA modified sol–gel process. The prepared samples were characterized by scanning electronic microscopy, X-ray diffractometer, Raman spectroscopy, UV–vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller measurement. Their photocatalytic activities were examined by the degradation of organic pollutants such as rhodamine-B and benzene in comparison with those of N-doped TiO2 with NH3 flow as N source under visible light (λ > 420 nm) irradiation. The results show that through the simple sol–gel process, nitrogen can be incorporated into crystal lattice of TiO2, leading to its response to visible light. With the presence of EDTA, the surface area of the prepared samples becomes larger, pore size smaller, and pore size distribution narrower. Additionally, the prepared N-doped TiO2 samples has better photocatalytic activity for organic compound degradation than that prepared with NH3 flow and there is an optimized N doping amount. The reason for the enhanced photocatalytic activity is discussed in detail. To the best of our knowledge, it is first time to report that N-doped TiO2 nanoparticles can have high enough activity for benzene degradation.

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► N doped TiO2 with high activity under visible light is prepared with EDTA as N source.
► The N doped TiO2 has high activity for benzene degradation under visible light.
► The mechanism for the high activity of the prepared sample is explored.