Photocatalytic Degradation of Phenol over Highly Visible-Light Active BiOI/TiO2 Nanocomposite Photocatalyst

BiOI/TiO2 nanocomposites were successfully prepared by the two-step method, co-precipitation/solvothermal method. The amount of BiOI in the composites were varied as 0, 5.0, 7.5, 10.0 and 12.5 mol%. XRD results exhibited sharp and narrow diffraction peaks of both BiOI and TiO2 in all composite samples. Morphologies of as-prepared samples consisted of spherical shapes of TiO2 and nanosheets of BiOI. Difuse Reflectance UV-visible (DR-UV-vis) spectra of composites drastically shifted into the visible range and the reduced band gap energies were observed. The composits obviously showed an enhanced phenol degradation of ca. 6 times higher than that of pure BiOI, pure TiO2 and Degussa P25. The maximum photocatalytic activity of ca. 68% was found for 10.0 mol% BiOI/TiO2 nanocomposite because of its increased visible-light-harvesting ability and its efficient electron-hole separation efficiency as observed from DR-UV-vis and PL spectra results