Characterization of iron-doped titania sol-gel materials

Fe/TiO2 materials at 1 wt% Fe content have been prepared by the addition of aqueous solutions of FeCl2 to titanium n-tetrabutoxide using hydrochloric acid (pH 3) as a hydrolysis catalyst. The obtained gel was thermally treated at 200, 400, 600 and 800 degreesC. Characterization of the materials was performed by FTIR, UV-Vis, Mossbauer and X-ray powder diffraction. FTIR spectra of the calcined samples showed the presence of highly hydroxylated TiO2. The XRD patterns show the coexistance of brookite, anatase and rutile TiO2 phases in samples treated up to 600 degreesC. In the sample treated at 800 degreesC rutile was the only phase observed. UV-Vis spectroscopy revealed that the band gap E-g of the samples increased with increased thermal treatment temperature. Mossbauer spectroscopy showed the coexistance of Fe2+ and Fe3+ on the TiO2 samples treated at high temperatures.