Preparation of Bi-doped TiO2 nanoparticles and their visible light photocatalytic performance

Bi-doped TiO2 photocatalysts were prepared by a hydrothermal method using nanotube titanic acid as the Ti precursor. The samples were characterized by X-ray diffraction, transmission electron microscopy, ultraviolet-visible diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy. Methyl orange (MO) was used as a model contaminant to evaluate the visible light photocatalytic activity of the Bi-doped TiO2 samples. We found that the Bi ions did not incorporate into the TiO2 lattice but instead existed in the form of BiOCl. The obtained BiOCl-composited TiO2 samples exhibited remarkable photocatalytic activity under visible light irradiation for the photodegradation of MO. The sample obtained when the Bi/Ti molar ratio was 1% and the hydrothermal treatment temperature was 130 °C (BTO-130-1) showed the highest photocatalytic activity. Moreover, a possible mechanism was proposed and the enhanced photocatalytic activity was discussed. The as-prepared catalyst also showed high photocatalytic activity for the photodegradation of 4-chlorophenol.

Graphical AbstractBi-doped TiO2 photocatalysts showed high visible light photocatalytic activity for the degradation of methyl orange and 4-chlorophenol. The high photoactivity was co-determined by single-electron-trapped oxygen vacancies (SETOVs) and the formation of a BiOCl/TiO2 composite. The formation of SETOVs during the process of NTA hydrothermal treatment accounts for the visible light sensitization, while the formed BiOCl/TiO2 composite improves the separation of photogenerated electrons and holes and prevents them from recombining.Figure optionsDownload full-size imageDownload as PowerPoint slide