Synthesis, characterization, and activities of visible light-driven Bi 2O 3–TiO 2 composite photocatalysts

Abstract

A series of Bi 2O 3–TiO 2 composite photocatalysts were prepared with a facile nonaqueous sol–gel method through varying the Bi–Ti atomic ratio and calcination temperature. The catalyst structures had been extensively characterized by using X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), UV–visible diffuse reflectance spectroscopy (UV–vis DRS). The characterization results revealed that all of the Bi 2O 3–TiO 2 composites exhibited smaller crystallite size, higher thermal stability and stronger absorbance in visible light range than pure TiO 2. The photocatalytic activities of as-prepared catalysts were evaluated by the degradation of methyl orange (MO). The results showed that the Bi–Ti atomic ratio of 0.0175 was an optimum in the photocatalytic activities under visible light irradiation and the calcination temperature affected both the physicochemical properties and photocatalytic activities of the catalysts. XPS and XRD were further used to characterize the stability of the photocatalyst, which maintained a high activity without obvious deactivation after five recycles of the degradation.