The Reactions of Organic Molecules on the Surfaces of the Oxides of Uranium and Ruthenium

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dc.contributor.advisor Idriss, Hicham en Hima, Madhavaram en 2007-07-06T08:59:05Z en 2007-07-06T08:59:05Z en 2001 en
dc.identifier THESIS 01-334 en
dc.identifier.citation Thesis (PhD--Chemistry)--University of Auckland, 2001 en
dc.identifier.uri en
dc.description Full text is available to authenticated members of The University of Auckland only. en
dc.description.abstract This work is devoted to investigating oxidation reactions over the surfaces of uranium oxides and ruthenium oxide. Oxidative coupling reactions were also considered and successfully carried out on polycrystalline β-UO3 in stoichiometric as well as catalytic conditions. Material characterization was conducted by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), BET and scanning electron microscopy (SEM). One of the most important finding in this work is the formation of furan (C4H4O) from C2 molecules over β-UO3 surfaces. Furan was observed from ethylene, ethanol, acetaldehyde and acetylene. This type of reaction was not observed on any metal oxide prior to this work. β-UO3 was far more active than α-U3O8 for furan formation for all the molecules that were investigated. Furan formation from these molecules appears to be driven by oxidation steps. These are related to the high oxidation state of U cations (U+6) as well as their potential presence in a six-fold coordination environment, ie, containing two vacancies to accommodate the coupling of two C2 molecules to the C4 furan product. Flow experiments and XRD analysis have shown that catalyst deactivation is associated with change in the bulk structure (reduction to α-U3O8 and UO2). Reactions of methanol, ethanol and CO were investigated over RuO2. Ruthenium oxide was active for the oxidation of methanol to formaldehyde and CO2, of ethanol to acetaldehyde and CO2, and of CO to CO2. The comparison between the reactivity of polycrystalline RuO2 and that of single crystal RuO2(ll0) showed strong similarities. Since the reaction pathways are very much alike on both single crystal and polycrystalline materials, the active centres on RuO2 are most likely the same. These active centres over RuO2 surfaces are traced back to the undercoordinated Ru atoms together with the presence of weakly bound undercoordinated oxygen species. en
dc.language.iso en en
dc.publisher ResearchSpace@Auckland en
dc.relation.ispartof PhD Thesis - University of Auckland en
dc.relation.isreferencedby UoA9998535414002091 en
dc.rights Restricted Item. Available to authenticated members of The University of Auckland. en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. en
dc.rights.uri en
dc.title The Reactions of Organic Molecules on the Surfaces of the Oxides of Uranium and Ruthenium en
dc.type Thesis en Chemistry en The University of Auckland en Doctoral en PhD en
dc.rights.holder Copyright: The author en

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