SURFACE-PROPERTIES OF IRON-TITANIA PHOTOCATALYSTS EMPLOYED FOR 4-NITROPHENOL PHOTODEGRADATION IN AQUEOUS TIO2 DISPERSION

Iron(III) doped specimens (0.01-5% atomic Fe :Ti) have been prepared by impregnating polycrystalline ''home prepared'' TiO2 (mainly anatase) and have been studied for photocatalytic degradation of 4-nitrophenol in aqueous dispersions. Some structural and surface properties have been studied by X-ray diffraction, specific surface area and porosity measurements and FTIR monitoring of pyridine, ammonia and methanoic acid adsorption for surface acidity and basicity. Their surface properties were compared with a corresponding series of photocatalysts prepared by a coprecipitation method. Adsorption of pyridine and ammonia indicates the presence of surface acid Lewis sites, a low concentration of surface Bronsted sites being present only in the samples prepared by impregnation. The photocatalytic experiments indicated that the presence of iron ions does not influence or is detrimental for the occurrence of the 4-nitrophenol photodegradation.