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  • 1
    Electronic Resource
    Electronic Resource
    A Catalysis Related Electrochemical Study of the V2O5/TiO2(Rutile) System (1995)
    s.l. : American Chemical Society
    Langmuir 11 (1995), S. 1024-1032 
    Details
    ISSN: 1520-5827
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/la00003a054
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Quantum-chemistry and catalysis in oxidation of hydrocarbons (1981)
    s.l. : American Chemical Society
    Accounts of chemical research 14 (1981), S. 1-7 
    Details
    ISSN: 1520-4898
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ar00061a001
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Untersuchungen der elektrischen Leitfähigkeit von Zinkoxyd (1959)
    Springer
    The European physical journal 155 (1959), S. 453-464 
    Details
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Zusammenfassung Die Ergebnisse der Leitfähigkeitsuntersuchungen von polykristallinem ZnO im Temperaturbereich 100 bis 700° C unter verschiedenen Bedingungen des Druckes werden angegeben. Nach der Meinung der Autoren wird im Temperaturbereich über 450° C die Temperaturabhängigkeit der Leitfähigkeit durch die Änderungen des Gleichgewichtzustandes der O2-Chemisorption auf der Oberfläche von ZnO bestimmt. Bei 450° C wird die Chemisorptionsgeschwindigkeit gleich Null und deshalb ist bei niedrigeren Temperaturen das Oberflächengleichgewicht schon „eingefroren“. Die Temperaturabhängigkeit der Leitfähigkeit entspricht dann der thermischen Aktivierung von Donatoren. Infolge des in der Randschicht entstehenden Potentialgradienten können die Zwischengitterzinkionen bei Zimmertemperatur in der Richtung der Oberfläche diffundieren, wobei das Gitter angebaut wird. Dieser Prozeß ist als Ursache der zwischen 20 bis 450° C festgestellten irreversiblen Leitfähigkeitsänderungen anzusehen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01333125
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    On the molecular mechanism of catalytic oxidation of olefins (1991)
    Springer
    Catalysis letters 9 (1991), S. 297-309 
    Details
    ISSN: 1572-879X
    Keywords: Butane oxidation ; oxide catalysis ; molybdenum oxide catalysts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract In every oxidation reaction two reactants take part: oxygen and the molecule to be oxidized. The reaction may thus start either by activation of the dioxygen (electrophilic oxidation) or by activation of the hydrocarbon molecule (nucleophilic oxidation). The surface of an oxide catalyst for selective oxidation must thus be tailored to perform a complex multistep operation on the reacting molecules, at the same time hindering those interactions that could lead to unwanted byproducts. A theoretical description of chemical reactions may be attempted on the basis of the concept of the potential energy hypersurface for molecular motions. The minima on such a hypersurface correspond to stable systems; i.e., to reactants and products of the reaction network investigated. As the networks for the oxidation of hydrocarbons on oxide surfaces are relatively large systems, even the semiempirical computation is time-consuming and further simplifications of the model must be adopted to make full description feasible. Analysis of experimental data suggests that as the form of the transition state is already determined at the preliminary stage of the reaction, the energy gradient estimated from the difference of total energies at two points chosen at relatively large distances between the reactants may be taken as an indication of the potential barrier encountered on approach from a given direction. Thus, reaction pathways characterized by the lowest energy barriers may then be analyzed. Calculations were carried out for the reaction pathways in the system composed on non-activated and activated butene interacting with molecular or atomic oxygen. A general conclusion may be formulated that the important functions of active centers of the oxidation catalyst consist in the adsorption of the reacting molecules in the appropriate mutual orientation and in modification of their relative electrophilic-nucleophilic character.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00773187
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Redox transformations of vanadium species at the rutile surface (1994)
    Springer
    Catalysis letters 27 (1994), S. 369-375 
    Details
    ISSN: 1572-879X
    Keywords: vanadium oxide/rutile catalyst ; monolayers of vanadium species ; redox transformations of vanadium species ; voltammetry of vanadium species
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Redox transformations of vanadium species, deposited on the surface of a rutile monocrystal by annealing rutile with V2O5 were investigated by cyclic voltammetry. Two different vanadium species were observed at the surface: first, present in the crystal lattice of rutile, which undergoes the redox transformation V4+/V3+ only, and the second, present at the surface, which undergoes both the V5+/V4+ and V4+/V3+ redox transformations. The latter appears only when the subsurface layer becomes saturated with the former.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00813924
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    The interaction of rutile (TiO2) surface with some catalytically active transition metal oxides during heating, studied by electrochemical methods (1999)
    Springer
    Topics in catalysis 8 (1999), S. 199-209 
    Details
    ISSN: 1572-9028
    Keywords: supported metal oxide catalysts ; rutile surface ; rutile electrochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The interaction of the surface of a rutile monocrystal (110 oriented) with the oxides of some transition metals (V, Mo, Cr, Mn and Nb) during heating of the crystal with these oxides was investigated by electrochemical methods. In all cases insertion of the metal atoms in the rutile surface was observed, the degree of insertion depending strongly on the metal in question and the conditions of experiment. The interaction of rutile surface with metal oxides changes dramatically the conditions of charge transfer at the rutile surface, which may influence the course of catalytic reactions occurring at the surface of rutile-supported transition metal oxide catalysts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1019169313005
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    Paper (German National Licenses)
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  • 7
    Electronic Resource
    Electronic Resource
    Die Veränderung der elektrischen Leitfähigkeit während des Überganges eines Gemisches von Zinkoxyd und Chromoxyd in den Spinell (1958)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 294 (1958), S. 269-281 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Abhängigkeit der elektrischen Leitfähigkeit von ZnO + Cr2O3-Mischungen (im Molverhältnis 1:1) von den Bedingungen des vorhergehenden Erhitzungsprozesses wurde untersucht. Es wurden ferner Messungen der Abhängigkeit der Leitfähigkeit vom Sauerstoffdruck durchgeführt. Die Ergebnisse werden interpretiert.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19582940503
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    Paper (German National Licenses)
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