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  • 1
    Digitale Medien
    Digitale Medien
    Supported organoactinides. Surface chemistry and catalytic properties of alumina-bound cyclopentadienyl and pentamethylcyclopentadienyl thorium and uranium hydrocarbyls and hydrides (1985)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 107 (1985), S. 641-652 
    Details
    ISSN: 1520-5126
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1021/ja00289a016
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  • 2
    Digitale Medien
    Digitale Medien
    Investigation of the sulfidation of Mo/TiO2-Al2O3 catalysts by TPS and LRS (1992)
    Springer
    Catalysis letters 15 (1992), S. 255-267 
    Details
    ISSN: 1572-879X
    Schlagwort(e): Temperature programmed sulfiding ; laser Raman spectroscopy ; Mo/Al2O3 ; Mo/TiO2-Al2O3
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract A series of Mo/Al2O3 and Mo/TiO2-Al2O3 catalysts were investigated by temperature programmed sulfiding (TPS) and laser Raman spectroscopy (LRS). The effect of TiO2 on the sulfidability of molybdena was studied in detail. It is found that Mo/Al2O3 catalysts can be partially sulfided by O-S exchange at low temperature, forming molybdenum oxysulfide. The Mo-S bond subsequently ruptures in the presence of H2 to produce H2S. At 530–550 K deep sulfiding of molybdenum oxysulfide occurs forming crystalline MoS2. When the surface of Al2O3 was covered by a monolayer of TiO2, the sulfiding rate of molybdena at low temperature was not only greatly increased, but H2S produced in the reduction of Mo-S species caused deep sulfiding of the catalyst which resulted in a decrease of the TPS peak temperature by 80–100 K. The results indicate that this promotion of the sulfiding of molybdena is enhanced with TiO2 loading. The function of TiO2 is explained by the weakened interaction between MoO3 and Al2O3 due to the coverage of the Al2O3 surface by TiO2.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00765269
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  • 3
    Digitale Medien
    Digitale Medien
    Partial oxidation of ethane to syngas over nickel‐based catalysts modified by alkali metal oxide and rare earth metal oxide (1999)
    Springer
    Catalysis letters 63 (1999), S. 167-171 
    Details
    ISSN: 1572-879X
    Schlagwort(e): partial oxidation of ethane ; syngas ; nickel‐based catalysts ; modification ; alkali metal oxide ; rare earth metal oxide ; thermal stability ; carbon deposition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The catalytic activity, thermal stability and carbon deposition of various modified NiO/γ‐Al2O3 and unmodified NiO/γ‐Al2O3 catalysts were investigated with a flow reactor, XRD, TG and UVRRS analysis. The activity and selectivity of the NiO/γ‐Al2O3 catalyst showed little difference from those of the modified nickel‐based catalysts. However, modification with alkali metal oxide (Li, Na, K) and rare earth metal oxide (La, Ce, Y, Sm) can improve the thermal stability of the NiO/γ‐Al2O3 and enhance its ability to suppress carbon deposition during the partial oxidation of ethane (POE). The carbon deposition contains graphite‐like species that were detected by UVRRS. The nickel‐based catalysts modified by alkali metal oxide and rare earth metal oxide have excellent catalytic activities (C2H6 conversion of ~100%, CO selectivity of ~94%, 7 × 104 l/(kg h), 1123 K), good thermal stability and carbon‐deposition resistance.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1019006129861
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  • 4
    Digitale Medien
    Digitale Medien
    Acid-base properties and the directions of oxidative transformation of methane over nickel-based catalysts (1996)
    Springer
    Catalysis letters 41 (1996), S. 165-169 
    Details
    ISSN: 1572-879X
    Schlagwort(e): acid-base properties ; oxidative transformation of methane ; nickel-based catalysts ; oxidative coupling of methane ; C2 hydrocarbon ; partial oxidation of methane ; syngas
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Two completely different behaviors of the oxidative transformation of methane (OTM) were performed on nickel-based catalysts because of different acid-base properties of those catalysts. The relatively acidic LaNiOx and LiNiLaOx/Al2O3 catalysts exhibit excellent performances in the partial oxidation of methane to syngas (POM). However, the relatively basic LiNiLaOx catalyst has a good performance in the oxidative coupling of methane to C2 hydrocarbons (OCM). The redox behaviors of those catalysts and the states of the nickel present were investigated by TPR techniques. TPR results indicated that the active component nickel of the working LaNiOx and LiNiLaOx/Al2O3 catalysts existed in the reduced state, and that of the working LiNiLaOx catalyst existed in the oxidized state under the same reaction conditions. It can be concluded that the acidic property favors keeping the reduced nickel and the reduced nickel is necessary for the POM reaction, whereas the basic property favors keeping the oxidized nickel and the oxidized nickel is necessary for the OCM reaction.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00811485
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  • 5
    Digitale Medien
    Digitale Medien
    A novel preparation method for porous noble metal/ceramic catalytic membranes (1999)
    Springer
    Journal of materials science 34 (1999), S. 2987-2996 
    Details
    ISSN: 1573-4803
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau
    Notizen: Abstract Adsorption at liquid/solid interface has been explored to prepare catalytically active ceramic membranes. Boehmite sol maintains its dynamic stability in the pH range of 3.5–4. Adsorption of metal salt on the sol particles can only be performed in the above pH range, but the adsorption can still be optimized by proper choice of ligand. Therefore, the effect of the ligands (NH3, Cl−, EDTA) on the adsorption of the noble metal ions (Pd(II), Pt(II), Pt(IV) and Rh(III)) as a function of pH on γ-Al2O3 particles was studied. Thus the noble metal complexes which can significantly adsorb in the above pH range were found. Using the complexes, the noble metal ion modified boehmite sols were synthesized. Then by the sol-gel process, the porous noble metal/ceramic cataytic membranes were prepared. The membranes were further characterized by N2 adsorption-desorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and SEM-WDX (wave dispersion of X-ray). The H2 and N2 permeation through these membranes at elevated temperatures was also measured. Based on the above experiments, the novel technique can produce the mesoporous catalytically active ceramic membranes without any defects and with a uniform dispersion of the active materials in the coating.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004616309085
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  • 6
    Digitale Medien
    Digitale Medien
    Low temperature synthesis of perovskite oxide using the adsorption properties of cellulose (2000)
    Springer
    Journal of materials science 35 (2000), S. 5639-5644 
    Details
    ISSN: 1573-4803
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau
    Notizen: Abstract La0.8Sr0.2CoO3 (LSCO) oxide powder was prepared using the adsorption properties of cellulose. The preparation process was studied by XRD, FTIR, TG-DTA and CO2-TPD techniques. The results of XRD, IR and TG-DTA testified that cellulose could successfully reserve the homogeneity of the solution system to the solid precursor. During the early stage of pyrolysis, cellulose was partially oxidized, and some COO− groups appeared in its texture, which were then complexed with the adsorbed metal ions, and effectively suppressed the aggregation of metal ions. Formation of a pure perovskite and the properties of the powder resulted were found to be significantly influenced by the cellulose to metal nitrate ratio. Also the properties of the resulting powder were greatly influenced by the calcination conditions. If the produced carbon dioxide could not be eluted in time, carbonate would be formed in the bulk. Hence, a high calcination temperature (〉800°C) was needed to acquire a pure phase LSCO. At optimized conditions, nano-crystal LSCO could be obtained at as low as 500°C.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004837920569
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  • 7
    Digitale Medien
    Digitale Medien
    Partial Oxidation of Ethane to Syngas over Supported Metal Catalysts (2000)
    Springer
    Reaction kinetics and catalysis letters 70 (2000), S. 311-317 
    Details
    ISSN: 1588-2837
    Schlagwort(e): Supported metal ; high temperatures
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The reaction performance for C2H6-O2 to syngas over different supported metal catalysts was investigated in a flow-reactor. The activated behavior of ethane is different from that of methane over the supported nickel catalysts. Although there may exist a gas phase reaction at high temperatures, over a Ni (or Rh)/γ-Al2O3 catalyst, the partial oxidation of ethane to syngas is a heterogeneous process, while over a Pt (or Pd)/γ-Al2O3 catalyst, it may be a homo-heterogeneous process. The Ni/γ-Al2O3 and Rh/γ-Al2O3 catalysts are suitable for partial oxidation of ethane to syngas at high temperatures.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1010397001697
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  • 8
    Digitale Medien
    Digitale Medien
    Control of the directions of oxidative transformation of methane over nickel-based catalysts by acid-base properties (1997)
    Springer
    Reaction kinetics and catalysis letters 62 (1997), S. 363-370 
    Details
    ISSN: 1588-2837
    Schlagwort(e): oxidative transformation of methane ; nickel-based catalysts ; acid-base properties ; partial oxidation of methane ; oxidative coupling of methane
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Two completely different directions of the oxidative transformation of methane (OTM) were performed on nickel-based catalysts due to the different acid-base properties of those catalysts. The relatively acidic LaNiOx and LiNiLaOx/Al2O3 catalysts exhibit excellent Partial Oxidation of Methane to Syngas (POM) performance. However, the relatively basic LiNiLaOx catalyst has a good Oxidative Coupling of Methane to C2 Hydrocarbons (OCM) activity. The basic properties of the catalyst makes it difficult to reduce nickel and keeps it in the oxidized state. Reduced nickel is necessary for POM and oxidized nickel for the OCM reaction.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02475477
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  • 9
    Digitale Medien
    Digitale Medien
    Mechanistic studies of methane partial oxidation to syngas over LiNiLaOx/Al2O3 catalyst (1999)
    Springer
    Reaction kinetics and catalysis letters 66 (1999), S. 273-279 
    Details
    ISSN: 1588-2837
    Schlagwort(e): Methane partial oxidation ; pulse reaction ; reaction mechanism ; LiNiLaOx/Al2O3 catalyst
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Temperature-programmed reduction (TPR) characterization of the LiNiLaOx/Al2O3 catalyst before or after partial oxidation of methane (POM) reaction and a series of O2, CH4 and CH4/O2 pulse reaction experiments over the catalyst under different pretreatments were performed. It was found that CH4 dissociatively adsorbs on active center nickel producing H2 and surface carbon, C(a). The surface carbon reacts with surface lattice oxygen or surface adsorbed oxygen to produce CO. Because the activation barrier for the reaction C(a)+ O(a)=CO(a) is the highest among all the elementary reactions, the ratedetermining step of the POM may be the reaction C(a)+O(a)=CO(a).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02475801
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  • 10
    Digitale Medien
    Digitale Medien
    ESCA studies on copper-cobalt based catalysts (1995)
    Springer
    Reaction kinetics and catalysis letters 56 (1995), S. 331-339 
    Details
    ISSN: 1588-2837
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The copper-cobalt catalysts for alcohol synthesis were prepared and studied by ESCA techniques (XPS and XAES) and TPR. The valence states of the surface elements were investigated for Co−Cu−Y based catalysts, and it was found that there were some reoxidation during the reaction. From the XPS and XAES results, strong interactions between copper and cobalt in the samples were presented, in agreement with the TPR experiments. The interacted copper-cobalt units could be the active sites for higher alcohol synthesis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02076038
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