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  • 1
    Digitale Medien
    Digitale Medien
    Characterization of surface species on V/SiO2 and V,Na/SiO2 and their role in the partial oxidation of methane to formaldehyde (1996)
    Springer
    Catalysis letters 40 (1996), S. 9-16 
    Details
    ISSN: 1572-879X
    Schlagwort(e): vanadium surface species ; silica-supported catalysts ; methane partial oxidation ; sodium poison ; V=O sites
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Silica-supported vanadium (1–8 wt%) and vanadium (5 wt%)-sodium (0.4 wt%) catalysts have been characterized by laser Raman spectroscopy, temperature-programmed reduction, X-ray photoelectron spectroscopy, NO + NH3 rectangular pulses and oxygen chemisorption. The presence of different vanadium species was correlated with activity and selectivity during the methane partial oxidation reaction. The pre-impregnation of the silica support with sodium favors vanadium dispersion, but strongly diminishes V=O concentration due to the formation of orthovanadate-like compounds. As a result of these modifications, methane conversion is strongly inhibited while formaldehyde decomposition is favored.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00807449
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  • 2
    Digitale Medien
    Digitale Medien
    Laser Raman spectroscopy (LRS) and time differential perturbed angular correlation (TDPAC) study of surface species on Mo/SiO2 and Mo,Na/SiO2. Their role in the partial oxidation of methane (1997)
    Springer
    Catalysis letters 48 (1997), S. 47-54 
    Details
    ISSN: 1572-879X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Silica-supported molybdenum (1.6 and 5.0 wt%) and molybdenum (5 wt%)-sodium (0.4 wt%) catalysts have been characterized by laser Raman spectroscopy (LRS), time differential perturbed angular correlation (TDPAC), temperature-programmed reduction (TPR) and X-ray photoelectron spectroscopy (XPS). The presence of different molybdenum species was correlated with activity and selectivity to formaldehyde during the methane partial oxidation reaction. The main species identified on the Mo(5.0 wt%) /SiO2 surface were MoO3 and monomeric species with a single Mo=O terminal bond. The pre-impregnation of the silica support with sodium strongly diminishes the Mo=O concentration due to the formation of Na2Mo2O7 species and tetrahedral monomers with a high degree of symmetry. As a result of these modifications, both methane conversion and formaldehyde formation are strongly inhibited. The combination of LRS and TDPAC techniques resulted in a powerful tool for the identification and quantification of the molybdenum species present on the surface of a silica support.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1019062617604
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  • 3
    Digitale Medien
    Digitale Medien
    Development and application of perovskite‐based catalytic membrane reactors (1998)
    Springer
    Catalysis letters 54 (1998), S. 69-78 
    Details
    ISSN: 1572-879X
    Schlagwort(e): catalytic membranes ; perovskites ; VOC combustion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The preparation and characterization of catalytic membranes containing La‐based perovskites are reported. The membranes were prepared by in situ crystallization of different perovskites inside a porous α‐alumina matrix. Preponderance of the Knudsen‐diffusion regime during membrane operation was obtained with perovskite loads of 2 wt% and higher. The catalytic membranes obtained were used as combustors of VOCs (toluene and methyl ethyl ketone) contained in air streams, at concentrations between 875 and 3450 ppmV, and space velocities of up to 27200 h-1. The membranes were operated in the flow‐through mode, which resulted in total VOC combustion at moderate temperatures.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1019003216521
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  • 4
    Digitale Medien
    Digitale Medien
    Effects of NO and solids on the oxidation of methane to formaldehyde (1994)
    Springer
    Catalysis letters 29 (1994), S. 339-348 
    Details
    ISSN: 1572-879X
    Schlagwort(e): formaldehyde ; gas-phase reactions ; methane partial oxidation ; oxide catalysts ; nitric oxide
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The selective oxidation of methane has been studied both in the presence and absence of solids (inert or catalysts) with and without NO added, at 1 bar of total pressure. NO enhances the yield to formaldehyde, while the solids favor its decomposition. These results, together with abundant literature data, show a maximum for formaldehyde yield of about 4.0%.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00807113
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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