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 Bi2O3-TiO2 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 Bi2O3-TiO2 composite was of smaller particle size, greater specific surface area, and had stronger absorbance in the visible light region than pure TiO2. The photocatalytic activity of the as-prepared catalyst was evaluated by degradation of rhodamine B under visible light irradiation (lambda > 400 nm); the as-prepared Bi2O3-TiO2 composite was substantially more active than pure TiO2. This was ascribed to the high surface area and the heterojunction structure.