Photooxidation of different organic dyes (RB, MO, TB, and BG) using Fe(III)-doped TiO2 nanophotocatalyst prepared by novel chemical method

The nano-structured Fe(III)-doped TiO2 photocatalysts with anatase phase have been developed for the oxidation of non-biodegradable different organic dyes like methyl orange ( MO), rhodamine B (RB), thymol blue ( TB) and bromocresol green (BG) using UV-Hg-lamp. The different compositions of FexTi1-xO2 (x = 0.005, 0.01, 0.05, and 0.1) nanocatalysts synthesized by chemical method ( CM), have been characterized by X-ray diffraction (XRD), UV-vis diffuse reflectance spectra, specific surface area ( BET), transmission electronic microscopy (TEM) analysis, XPS, ESR and zeta potential. From XRD analysis, the results indicate that all the compositions of Fe( III) doped in TiO2 catalysts gives only anatase phase not rutile phase. For complete degradation of all the solutions of the dyes ( MO, RB, TB, and BG), the composition with x = 0.005 is more photoactive compared all other compositions of FexTi1-xO2, and degussa P25. The decolorization rate of different dyes decreases as Fe( III) concentration in TiO2 increases. The energy band gap of Fe(III)-doped TiO2 is found to be 2.38 eV. The oxidation state of iron has been found to be 3+ from XPS and ESR show that Fe3+ is in low spin state. (C) 2008 Elsevier B. V. All rights reserved.