Facile fabrication of N-doped TiO2 nanocatalyst with superior performance under visible light irradiation

A facile and convenient method has been developed to prepare N-doped TiO2 visible light nanocatalysts, which is performed by a solid-state calcination of one-dimensional titanate nanotubes with an inorganic ammonium salt (NH4Cl). The ion-exchange reaction between layered nanotubes and NH4Cl contributes to the phase transition to crystalline TiO2 combined with N doping. X-ray diffraction and transmission electron microscopy are carried out to study the phase evolution, compositions, and morphologies of obtained samples. X-ray photoelectron spectroscopy reveals that the N dopant in TiO2 is assigned to the interstitial NHx species. Both the phase transition and N doping are further confirmed by UV–vis diffuse reflectance spectra. All N-doped TiO2 materials exhibit significantly higher visible light activities than that of the parent nanotubes for degrading rhodamine B. In addition, the N-doped TiO2 nanocatalyst holds a strong stability and durability for the removal of organic pollutions.