Ultrasonic-assisted synthesis of visible-light-driven TiO2/Bi2O3 nanocomposite photocatalysts: characterization, properties and azo dye removal application

TiO2/Bi2O3 nanocomposites (Sonic-TiO2/Bi2O3) were synthesized via combination of thermohydrolysis and ultrasonic chemical precipitation techniques. For the sake of contrast, pure TiO2 nanoparticles (NPs) and conventional TiO2/Bi2O3 nanocomposites (Stir-TiO2/Bi2O3) were also prepared. XRD, FT-IR, FE-SEM, TEM, EDX and UV-Vis studies were adopted to determine the structural, chemical composition and optical properties of the as-prepared samples. The photocatalytic activities of the samples were evaluated by measuring the photo-degradation of Orange II in aqueous solution under visible light irradiation (lambda a parts per thousand yen 400 nm). The efficiencies towards OII degradation were determined to be 44.0, 81.8 and 94.7 % for pure TiO2 NPs, Stir-TiO2/Bi2O3 and Sonic-TiO2/Bi2O3, respectively. These results reveal that the loading of Bi2O3 can greatly improve visible light photocatalytic performance of TiO2, and the ultrasonic treatment can also improve photocatalytic performance of TiO2/Bi2O3 nanocomposites. Based on the experimental results, possible enhanced visible-light photocatalytic degradation mechanisms were also discussed. The present findings may provide a new approach to synthesize high efficiency TiO2/Bi2O3 nanocomposite photocatalysts.