Structure and properties of BiOI/TiO 2 (A) photocatalysts with different Bi/Ti molar ratios

Abstract

BiOI-sensitized nano-anatase (TiO 2 (A)) photocatalysts were prepared by a deposition method at room temperature, and characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL), and UV-Vis diffuse reflectance spectra (UV-Vis DRS). The photocatalytic activities were evaluated by photo-degradation experiments of rhodamine B. With increasing BiOI content, the absorption intensity of BiOI/TiO 2 (A) increases in the 370-630 nm region and the absorption band edge redshifts. The UV and visible light photocatalytic activities increase, reaching a maximum when the Bi/Ti molar ratio is 1.7%. The 1.7% BiOI/TiO 2 (A) catalyst exhibits much higher visible-light photoactivity than P25, and its UV-light photoactivity is slightly higher than that of P25. The UV and visible light photocatalytic activities of BiOI/TiO 2 (A) with similar BiOI content are lower than those of BiOI/P25 catalysts. Compared with TiO 2 (A), 1.7% BiOI/TiO 2 (A) shows higher UV and visible light photoactivities. This is attributed to the strong absorption in the 370- 630 nm region, the redshift of the absorption band edge, and the effective transfer of the photogenerated electrons and holes, which reduces the recombination of electron-hole pairs. © Editorial office of Acta Physico-Chimica Sinica.