Physicochemical and catalytic properties of iron-doped silica - the effect of preparation and pretreatment methods

Chemical vapor deposition (1wt% of iron) and wet and wetness impregnations (both giving Fe loading of 1.6 and 2.9 wt%) have been applied for the formation of iron-doped silica. The obtained materials were characterized by means of low-temperature N-2 adsorption, XRD, TEM, H-2-TPR, ESR, and chernisorption of CO and O-2. Their catalytic activity was tested in isopropanol decomposition and oxidation of methanol to formaldehyde. Depending on the preparation procedure various levels and strengths of Fe-silica interactions were observed. The activation conditions determine the nature of the Fe species formed. Fe3+ isolated species are active in isopropanol dehydration whereas Fe-oxide centers exhibit very high selectivity in methanol oxidation to methylformate and formaldehyde. (C) 2003 Elsevier Inc. All rights reserved.