Highly Efficient Visible-Light-Induced Photocatalytic Activity of Nanostructured AgI/TiO₂ Photocatalyst

Abstract

Nanostructured AgI/TiO(2) photocatalyst was synthesized by a feasible approach with AgNO(3), LiI, and Ti(OBu)(4) and characterized by X-ray diffraction, transmission electron microscopy, angle-dependent X-ray photoelectron spectroscopy, diffusive reflectance UV-vis spectroscopy, Raman spectroscopy, photoluminescence, and the Brunauer-Emmett-Teller technique. The results of characterization reveal that the nanostructured AgI/TiO(2) has a novel core/shell/shell nanostructure of AgI/Ag-I(2)/TiO(2). Compared with TiO(2) (P25) supported AgI, the formation of the nanostructure results in substantial shifting of the absorption edge of AgI to red, enhancement of the absorption intensity, and the appearance of a strong tail absorption above 490 nm, which is assigned to the absorption of I(2) and Ag. Photocatalytic tests show that the nanostructured AgI/TiO(2) photocatalyst exhibited very high visible-light-induced photocatalytic activity for the photodegradation of crystal violet and 4-chlorophenol, which is 4 and 6 times higher than that of P25 titania supported AgI, respectively. The highly efficient visible-light-induced photocatalytic activity of the nanostructured AgI/TiO(2) is attributed to its strong absorption in the visible region and low recombination rate of the electron-hole pair due to the synergetic effect among the components of AgI, Ag, I(20, and TiO(2) in the nanostructured AgI/TiO(2).