Iron-doped titania powders prepared by a sol-gel method. Part II: Photocatalytic properties

Samples of iron-doped titania containing different amounts of Fe (0.5-5wt%) prepared from TiCl4 and Fe(III) acetylacetonate by a sol-gel method were t ested as photocatalysts under near-UV irradiation for EDTA oxidation and fo r Cr(VI) reduction. Their efficiency has been compared with specimens prepa red by impregnation of TiO2 (Degussa P-25) with iron nitrate or iron acetyl acetonate and found to be less active in both redox systems, in spite of th e favorable structural properties. The preservation of the P-25 structure i n samples prepared by impregnation and a larger amount of defects provided by the preparation technique, acting as recombination centers, seem to be t he most important factors affecting the activity. The addition of EDTA high ly increases the rate of Cr(VI) reduction, the influence being remarkable i n all iron-doped samples. (C) 1999 Elsevier Science B.V. All rights reserve d.