Synthesis and characterization of Mo–Sb–S tridoped TiO2 nanoparticles with enhanced visible light photocatalytic activity

In this work, a novel Mo–Sb–S tridoped TiO2 nanoparticles possessing enhanced visible light photocatalytic activity were prepared by a sol–gel method. The as-prepared catalyst was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy, energy dispersive X-ray, nitrogen adsorption–desorption isotherms, and UV–vis diffuse reflectance spectroscopy. The results of XRD and TEM indicated that the average size of Mo–Sb–S tridoped TiO2 nanoparticles was approximately 8–9 nm, which is smaller than that of TiO2 co-doping or doping with Mo, Sb and S (11–16 nm). The photocatalytic activity of Mo–Sb–S tridoped TiO2 nanoparticles was evaluated by photodegradation of methylene blue (MB) in aqueous solution under visible light irradiation. The results revealed that the prepared Mo–Sb–S tridoped TiO2 nanoparticles possess excellent performance on degradation of MB. By analyzing the structure and photocatalytic activity of Mo–Sb–S–TiO2 under visible light irradiation, the probable mechanism of tridoped TiO2 for enhancing visible light photocatalytic activity was postulated that the co-operation of metal elements Mo and Sb as well as nonmetal elements S not only led to appreciable narrowing of the band gap, but also suppressed the recombination of the photo-generated electrons and holes, thus greatly improved the photocatalytic activity under visible light irradiation.