Remarkable catalytic activity of Bi2O3/TiO2 nanocomposites prepared by hydrothermal method for the degradation of methyl orange

Visible light Bi2O3/TiO2 nanocomposites are successfully prepared with different dosages of Bi2O3 by hydrothermal process. All the as-prepared samples are characterized by X-ray diffraction (XRD), scanning and transmission electron microscopes (SEM and TEM), Brunauer-Emmett-Teller analysis (BET), N-2 adsorption-desorption measurement, and UV-Vis diffuse reflectance spectra (DRS). XRD and Raman spectra reveal the anatase phase of both TiO2 and Bi2O3/TiO2 nanocomposites. X-ray diffraction patterns demonstrate that the bismuth ions did not enter into the lattice of TiO2, and Bi2O3 is extremely dispersive on the surface of TiO2 nanoparticles. The incorporation of Bi2O3 in TiO2 leads to the spectral response of TiO2 in the visible light region and efficient separation of charge carriers. The enhanced visible light activity is tested by the photocatalytic degradation of methyl orange under light illumination, and the performance of Bi2O3/TiO2 nanocomposites are superior than that of pure TiO2 which is ascribed to the efficient charge separation and transfer across the Bi2O3/TiO2 junction. Bi2O3/TiO2 nanocomposite (20 mg) loaded with 0.25 of Bi2O3 dispersed in 50 ml of 5 ppm methyl orange solution exhibited the highest photocatalytic activity of 98.86% within 240 min of irradiation, which is attributed to the low band gap, high surface area, and the strong interaction between Bi2O3 and TiO2.