Date of Award

1984

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemical Engineering

Abstract

Due to the potential of iron-ruthenium bimetallic heterogeneous catalysis in a number of high demand, energy related processes, this study was undertaken to synthesis and characterize a series of bimetallic Iron-Ruthenium alloy and clusters. A material science approach was taken which relies on the physical and chemical characterization of catalyst material itself rather than the classical chemical kinetics investigation of the catalytic reaction. Various methods have been employed for the determination of surface and bulk properties of catalysts during dehydration-hydration, and oxidation-reduction treatments. In the case of the bimetallic systems, the use of ('99)Ru and ('57)Fe double labelled Mossbauer experiments was most useful. Additional information was obtained from ESCA, X-ray diffraction, and infrared spectroscopy. This array of physical techniques provided complementary details for the complete characterization of the systems of interest. It is known that iron cannot be reduced beyond the ferrous state when ion exchanged in Y-zeolite. Thus, the reduction behavior of iron on zeolite surfaces is considered a classical problem in catalytic research. Several attempts were made to modify the reduction behavior of iron. One approach was to introduce ruthenium into the system to encourage hydrogen spillover which should provide the reactive hydrogen atom as the reducing agent. Utilizing the preparation method designated as "Homogeneous-Deposition", the iron was reduced and the formation of hcp iron-ruthenium clusters on the surface of Y-zeolite was confirmed. To elucidate the nature of the interaction between iron and ruthenium and to evaluate the chemical differences of the solid state reaction during the preparation of bimetallic iron-ruthenium, the products formed when ruthenium trichloride is mixed with a variety of iron salts and oxides were investigated. The anions associated with the metal in the initial material influenced the formation and the nature of bimetallic particles. A unique preparative method based on the reaction of a cation exchanged zeolite with a metal-containing coordination complex anion was extended to synthesize the mixed iron-ruthenium cyanide polynuclear complexes directly on the zeolite. Under reduction conditions hcp iron-ruthenium bimetallic alloy was detected. This preparative method could provide an alternative way to stabilize polymetallic particles on zeolites.

Pages

182

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