PREPARATION AND CHARACTERIZATION OF IRON CATALYSTS ON PILLARED CLAYS AND PHOSPHORUS CONTAINING MOLECULAR SIEVES

Date of Completion

January 1987

Keywords

Chemistry, Inorganic

Degree

Ph.D.

Abstract

Mossbauer, EPR and UV-visible spectroscopic techniques has been used to study the environment of ferric Fe $\sp{3+}$ ions doped into alumina-pillared bentonite clay materials. Results suggest that the ferric ions can preferentially occupy different sites in the clay depending upon synthetic conditions. In addition, evidence is presented for the Fe $\sp{3+}$ ions being coordinated within the pillar itself. N-decane hydrocracking experiments indicate that the catalytic activity and selectivity of these materials depends upon the location of the ferric ions within the clay. During catalytic reaction the chemical state of the iron changes as indicated by Mossbauer spectroscopy and X-ray diffraction data, after catalysis, indicate that these materials are not thermally stable.^ In addition, metallic iron catalysts were prepared on aluminophosphate and silicoaluminophosphate molecular sieves vis microwave decomposition of organometallic precursors in an argon plasma. Mossbauer spectroscopy was employed to characterize the prepared catalysts and evidence exists for the preparation of small metallic iron particles, in the superparamagnetic region. Furthermore, results obtained provide evidence which suggest that the state of dehydration of the catalyst support, the surface chemistry and type of support are important factors to be taken into consideration when one investigates the feasibility of preparing zerovalent small metal particles on supports via microwave discharge methods. Experiments suggest that the higher the acidity of the surface, the less likely the possibility of small metal particle preparation on surfaces. ^

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