Preparation of a visible light-driven Bi2O3–TiO2 composite photocatalyst by an ethylene glycol-assisted sol–gel method, and its photocatalytic properties

A visible light-driven Bi 2 O 3 –TiO 2 composite photocatalyst was prepared by an ethylene glycol-assisted sol–gel method in which ethylene glycol acted as a polycondensation agent to capture metal ions by reacting with bismuth and titanium sources via a complex polycondensation pathway. The photocatalyst was characterized by X-ray photoelectron spectroscopy, X-ray diffraction, acquisition of N 2 adsorption–desorption isotherms, transmission electron microscopy, and UV–visible diffuse reflectance spectroscopy. The results revealed that the Bi 2 O 3 –TiO 2 composite was of smaller particle size, greater specific surface area, and had stronger absorbance in the visible light region than pure TiO 2 . The photocatalytic activity of the as-prepared catalyst was evaluated by degradation of rhodamine B under visible light irradiation ( λ > 400 nm); the as-prepared Bi 2 O 3 –TiO 2 composite was substantially more active than pure TiO 2 . This was ascribed to the high surface area and the heterojunction structure.