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

Abstract

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 N2 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 (λ > 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.