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  • 1
    Electronic Resource
    Electronic Resource
    Application of Ru exchanged zeolite-Y in ammonia synthesis (1992)
    Springer
    Catalysis letters 14 (1992), S. 339-348 
    Details
    ISSN: 1572-879X
    Keywords: Ammonia synthesis ; Ru-zeolite ; metal clusters ; conversion measurements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Na-Y zeolite was cation exchanged with Ru(NH3)6Cl3 yielding at 25% exchange level a light-purple solid which was active in ammonia synthesis at atmospheric pressure. Pulse conversion experiments show that the catalyst stores nitrogen as it was observed with the conventional iron catalyst. At 810 K the conversion reached about 20% of the maximum conversion of the iron catalyst. The catalyst deactivated reversibly within 30 h due to agglomeration. The active species in the catalyst is most likely a cluster-like Ru metal particle prevented from sintering under the reducing conditions of catalysis by the zeolite framework.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00769672
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Ruthenium supported on zeolite A: preparation and characterisation of a stable catalyst for ammonia synthesis (1994)
    Springer
    Catalysis letters 25 (1994), S. 61-74 
    Details
    ISSN: 1572-879X
    Keywords: Ammonia synthesis ; supported ruthenium catalyst ; dispersed ruthenium ; instationary kinetics ; lifetime effects ; ruthenium oxidation ; surface analysis ; XPS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Reaction of Ru(NH3)6Cl3 with Na-A and K-A zeolites yielded oligomeric amino-oxo-complexes supported on the zeolite. Controlled thermal activation under hydrogen converted the precursor in a two-step reaction into an active catalyst with good long-term stability and resistance against small doses of oxygen poison. Several nanometers sized Ru metal particles are chemically bonded to the zeolite surface which provides in the K form an alkali promoter at the metal-zeolite interface. Extensive oxidation breaks the metal-support anchoring and re-reduction produces Ru metal particles sintering rapidly into large metal crystals with only small residual catalytic activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00815416
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Surface characterization of ruthenium-exchanged Y-zeolite used in ammonia synthesisPaper presented at ECASIA 91, Hungary, 14-18 October 1991. (1992)
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 18 (1992), S. 650-654 
    Details
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Na—Y zeolite was cation exchanged with Ru and tested in ammonia synthesis at atmospheric pressure. Activities up to ∼10% of the commercial iron catalyst scaled by the active surface area were observed. Characterization of the zeolites with XPS was complemented with reference thermal desorption spectroscopy data on a polycrystalline Ru metal surface. The catalysts showed high thermal stability in in situ reduction-oxidation cycles. The chemical state of the Ru will be discussed. From shift measurements the Ru is metallic in the active state, but line shape arguments point to a cluster-like particle morphology. The location of the Ru inside or outside the zeolite framework will be discussed.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/sia.740180903
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    Paper (German National Licenses)
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