Synthesis of samarium- and nitrogen-co-doped TiO2 by modified hydrothermal method and its photocatalytic performance for the degradation of 4-chlorophenol

Sm- and nitrogen-co-doped TiO2 (Sm–N–TiO2) catalysts were prepared via the modified hydrothermal method using tetrabutyl titanate as the precursor and calcination at 200 °C. The microstructure of the sample was characterized by X-ray diffraction (XRD), ultraviolet–visible diffuse reflection spectroscopy (UV–vis-DRS), Fourier transform infrared (FTIR) spectra and X-ray photoelectron spectroscopy (XPS). The average particle size was ca. 16.0 nm as calculated from XRD patterns. Sm–N–TiO2 nanocrystalline showed strong visible-light response and high photocatalytic activity for 4-chlorophenol degradation under irradiation by visible-light (400–500 nm). The high visible-light photocatalytic activity of the obtained Sm–N–TiO2 might result from the incorporation of nitrogen atoms in TiO2, which extended the spectral response to the visible region, and Sm2O3 facilitated the excited electron transfer and hence suppressed efficiently the recombination of photoproduced electron–hole.