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  • Theoretical, Physical and Computational Chemistry  (2)
  • cyclohexane dehydrogenation  (2)
  • X-ray diffraction  (1)
Materialart
Erscheinungszeitraum
Schlagwörter
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Catalysis letters 21 (1993), S. 309-320 
    ISSN: 1572-879X
    Schlagwort(e): Sol-gel catalysts ; platinum-tin catalysts ; platinum dispersion ; X-ray diffraction ; energy dispersive X-ray analysis ; EDX analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Highly dispersed platinum was found in Pt-Sn/Al2O3 catalysts prepared by the sol-gel method, i.e., cogelation of aluminum tri-sec-butoxide and tetrabutyltin and subsequent impregnation with hexachloroplatinic acid. X-ray diffraction studies showed that the cell parameter of pure platinum is not modified in bimetallic Pt-Sn samples. Moreover, energy dispersive X-ray analysis studies (EDX) showed that platinum, but not tin, was detected in the catalysts where tin was incorporated by the sol-gel coprecipitation of tin and aluminum. Incorporation of tin into the alumina network is suggested.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Journal of sol gel science and technology 8 (1997), S. 847-849 
    ISSN: 1573-4846
    Schlagwort(e): platinum-tin catalysts ; Pt-Sn sol-gel catalysts ; cyclohexane dehydrogenation ; n-hexane conversion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Tin-alumina supports were prepared by cogelation of aluminum tri-sec-butoxide and tetrabutyltin or tin tetrachloride. Aqueous or acetone platinum solutions were used for impregnation. The results show that the specific surface area and the acidity of the catalysts were only slightly modified by the metal precursors used. On cyclohexane dehydrogenation and n-hexane conversion, high selectivity to olefins and low cracking products were detected.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Journal of sol gel science and technology 8 (1997), S. 847-849 
    ISSN: 1573-4846
    Schlagwort(e): platinum-tin catalysts ; Pt-Sn sol-gel catalysts ; cyclohexane dehydrogenation ; n-hexane conversion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Tin-alumina supports were prepared by cogelation of aluminum tri-sec-butoxide and tetrabutyltin or tin tetrachloride. Aqueous or acetone platinum solutions were used for impregnation. The results show that the specific surface area and the acidity of the catalysts were only slightly modified by the metal precursors used. On cyclohexane dehydrogenation andn-hexane conversion, high selectivity to olefins and low cracking products were detected.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 67 (1998), S. 399-409 
    ISSN: 0020-7608
    Schlagwort(e): Au ; Pt ; H2 adsorption ; AuPt clusters ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Linear and triangular AuPtn cluster reactions with H2 are studied theoretically, using ab initio multiconfiguration self-consistent field (MC-SCF) calculations, followed by extensive multireference configuration interaction (MR-CI) variational and perturbative. Both the linear dimer and the triangular trimers capture the hydrogen molecule by the Pt cluster side and by the Au cluster side. Gold has an electronic effect on the Pt activity, more important than a geometrical one, poisoning the Pt activity to dissociate H2 and lowering the adsorption heats. This effect is stronger in the AuPt dimer, where the H2 capture occurs only at the molecular level, without showing hydrogen bond dissociation. The trimers look more active, relaxing the H(SINGLE BOND)H bond until breakage. No activation barriers are observed in all the cases considered. The hydrogen molecule is not able to cross the clusters due to the large barriers present.   © 1998 John Wiley & Sons, Inc. Int J Quant Chem 67: 399-409, 1998
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 70 (1998), S. 1029-1035 
    ISSN: 0020-7608
    Schlagwort(e): Chemistry ; Theoretical, Physical and Computational Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The basic and fundamental mechanisms governing the catalytic reaction of small iridium clusters with H2 are presented here with the purpose to determine its behavior in hydrogenation reactions. The iridium dimer/s lowest states in interaction with H2 potential energy surface were obtained using ab initio multiconfigurational self-consistent-field calculations (MC-SCF), with relativististic pseudopotentials. The electronic correlation contribution was included by configurations interaction (CI) calculations, which considered a variational part plus a second-order perturbative part. The Ir2+H2 reactions were developed in the C2v symmetry. The Ir2's five lowest electronic states were determined, 5Πg, 3Πg, 1Σg+, 3Σu+, and 5Σg, and studied when reacted with H2. It was found that the iridium dimer, in these five states, might capture and break the H—H bond, spontaneously in certain cases and after surmounting activation barriers in other cases.   © 1998 John Wiley & Sons, Inc. Int J Quant Chem 70: 1029-1035, 1998
    Zusätzliches Material: 6 Tab.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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