“HIGHLY CONCENTRATED AND DISPERSED FE OXIDE CATALYSTS CHARACTERIZED BY MÖSSBAUER SPECTROSCOPY”.

S. G. MARCHETTI, A. GERVASINI AND C. MESSI.

Salamanca, España

Congreso; “EUROPACAT-IX”; 2009

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:EN-US; mso-fareast-language:IT;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> Mössbauer spectroscopy was used as a performing tool to investigate the nature, electronic, and magnetic properties of Fe oxide centers of series of supported Fe-based catalysts. The catalysts contained high Fe oxide concentrations (from 6 to 8 wt.% of Fe2O3) deposited on different supports (SiO2, SiO2-Al2O3, SiO2-Nb2O5, and SiO2-ZrO2) by two preparation methods (adsorption-equilibrium and wet impregnation). The preparation method directed the state of aggregation (superparamagnetic a-Fe2O3 or paramagnetic Fe3+ species) on the support surface. The presence of isolated Fe3+ species, associated with Lewis acid centers, gave good catalytic activity in reactions requiring Lewis acid catalysis, as proved in the a-pinene oxide isomerisation to a-campholenic reaction.