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 b y 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 b een studied by X-ray diffraction, specific surface area and porosity m easurements and FTIR monitoring of pyridine, ammonia and methanoic aci d adsorption for surface acidity and basicity. Their surface propertie s were compared with a corresponding series of photocatalysts prepared by a coprecipitation method. Adsorption of pyridine and ammonia indic ates the presence of surface acid Lewis sites, a low concentration of surface Bronsted sites being present only in the samples prepared by i mpregnation. The photocatalytic experiments indicated that the presenc e of iron ions does not influence or is detrimental for the occurrence of the 4-nitrophenol photodegradation.