STRUCTURAL CHARACTERIZATION OF FE/TI OXIDE PHOTOCATALYSTS BY X-RAY, ELECTRON-SPIN-RESONANCE, AND MOSSBAUER METHODS

The polycrystalline solids TiO//2-Fe//2O//3, with iron contents in the range 0-10 at%, prepared by coprecipitation and by impregnation, and treated in air at temperatures in the range 500-1000 degree C, have been studied by X-ray, ESR, and Moessbauer methods. The TiO//2 in the samples treated at 800 and 1000 degree C always forms the rutile phase and the Fe**3** plus has a rather low solubility in it (approx. 0. 1 at%). The Fe**3** plus in excess forms the antiferromagnetic pseudobrookite phase (Fe//2TiO//5). The samples treated at 500 and 650 degree C show a dependence on the preparation method. The relevance of these results to the photocatalytic properties shown by these solids for the photoreduction of dinitrogen to ammonia is discussed.