The composing effect of bismuth on titania hollow microspheres for their visible-light photocatalytic activity

Bismuth-composed titania hollow microspheres are fabricated by an impregnation-calcination method using hydrothermally prepared titania hollow microspheres as precursors and Bi(NO3)(3) as the Bi resource. A series of characterization methods and analyses, including scanning electron microscopy, transmission electron microscopy, X-ray diffraction, N-2 adsorption-desorption isotherms, Fourier transform infrared spectroscopy and UV-vis spectroscopy were carried out to confirm the successful synthesis of Bi-TiO2 photocatalysts. The photocatalytic activity is evaluated by photocatalytic decolorization of methyl orange (MO) aqueous solution at ambient temperature under visible-light irradiation. The results show that Bi-composing greatly enhances the visible-light photocatalytic activity of TiO2 hollow microspheres. When the atomic ratio of Bi/Ti (R-Bi) is increased from 0 to 0.5, the photocatalytic activity of the samples increases. In particular, at R-Bi = 0.5, it shows the highest photocatalytic activity. The Bi-components contain two narrow band gap semiconductors of Bi2O3 and Bi4Ti3O12 on the surface of TiO2 hollow microspheres. The results imply that Bi-composing induces the shift of the absorption edge into the visible-light range and the enhancement of visible-light absorption. Furthermore, the formation of the Bi2O3/TiO2 heterojunction and the special multilayer crystal structure of Bi4Ti3O12 could efficiently reduce the recombination of photo-generated electrons and holes.

Automated summary

Bismuth-composed titania hollow microspheres were fabricated using hydrothermally prepared titania hollow microspheres as precursors and Bi(NO3)(3) as the Bi resource. Various characterization methods were used to confirm the successful synthesis of Bi-TiO2 photocatalysts. The addition of bismuth greatly enhanced the visible-light photocatalytic activity of TiO2 hollow microspheres.