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Abstract: The catalytic activity of CuZn catalysts in the synthesis of methanol is related to those reduced Cu species, which originate from the Cu x Zn1−x O solid solution of wurtzite-like structure. Copper cations in the Cu x Zn1−x O solid solution are localized in the extended stacking faults of the ZnO lattice. Copper sites could be supposedly described as the product of introducing (OH)⋯Cu⋯(OH) to the planar defects of zinc oxide structure. Hydroxyl groups stabilize the planar defects of ZnO. The process of the samples reduction leads to the formation of flat Cu0 particles over the surface of zinc oxide. The planar defects of ZnO structure are preserved in the reduced state. During the reoxidation, copper atoms return back to the extended stacking faults of ZnO as the tape-like clusters of flat-square coordinated copper cations. [Copyright &y& Elsevier]

A conventional Ni + YSZ/YSZ anode half-cell (the Research Center Jülich) and the Ni + YSZ/YSZ planar half cell washcoated by a layer of the Ru + Ni-doped perovskite-based nanocomposite (Ru + Ni/LaPrMnCr/YSZ) were compared in terms of their activities and selectivities in the steam reforming of methane. The kinetic measurements were carried out in a laboratory scale plate-type reactor, and results were interpreted using computational models. A power-law kinetic model was verified against the experimental data, and parameters were estimated. Both numerical prediction and experimental testing indicate that the nanocomposite coated Ni + YSZ/YSZ plate shows much better catalytic performance under the middle-temperature operating conditions. CFD simulations show that for the high activity of thermally conductive catalytic plates, superior heat transfer performance is observed in the lab-scale reactor. The lab-scale data were successfully up-scaled for the case of steam reforming of natural gas on a structured catalyst at realistic operation conditions. Up to 700 °C, the pilot test data obtained with the structured catalyst comprised of three stacked parallel Ni–Al plates (50 × 50 × 1 mm) coated with perovskite-based nanocomposite correlate quite good with the 1-D plug-flow reactor model predictions assuming the proposed kinetics. [ABSTRACT FROM AUTHOR]

Abstract: Active components comprised of fluorite-like Ln x (Ce0.5Zr0.5)1− x O2− y (Ln=La, Pr, Sm) and perovskite-like La0.8Pr0.2Mn0.2Cr0.8O3 mixed oxides and their composites with yttria-doped zirconia (YSZ) promoted by precious metals (Pt, Ru) and/or Ni were supported on several types of heat-conducting substrates (compressed Ni–Al foam, Fecralloy foil or gauze protected by corundum layer, Cr–Al–O microchannel cermets, titanium platelets protected by oxidic layer) as well as on honeycomb corundum monolithic substrate. These structured catalysts were tested in pilot-scale reactors in the reactions of steam reforming of methane, selective oxidation of decane and gasoline and steam/autothermal reforming of biofuels (ethanol, acetone, anisole, sunflower oil). Applied procedures of supporting nanocomposite active components on monolithic/structured substrates did not deteriorate their coking stability in real feeds with a small excess of oxidants, which was reflected in good middle-term (up to 200h) performance stability promising for further up-scaling and long-term tests. Equilibrium yield of syngas at short contact times was achieved by partial oxidation of decane and gasoline without addition of steam usually required to prevent coking. For the first time possibility of successive transformation of biofuels (ethanol, acetone, anisole, sunflower oil) into syngas at short contact times on monolithic catalysts was demonstrated. This was provided by a proper combination of active component, thermal conducting monolithic substrates and unique evaporation/mixing unit used in this research. [Copyright &y& Elsevier]

Abstract: Open cell metal foams made from Ni, Fe–Cr steel and Ni–Al intermetallic were studied as candidate catalyst supports for the internal indirect methane steam reforming. All the samples exhibited good corrosive resistance during 500–1000h testing in H2–H2O–Ar environment at 600°C. NiO/8YSZ composite based catalysts doped with fluorite-like (Pr0.3Ce0.35Zr0.35O2) or perovskite-like (La0.8Pr0.2Mn0.2Cr0.8O3) complex oxides with high lattice oxygen mobility and promoted with Pt or Ru were prepared and deposited on the foam-structure supports. Both good catalyst adhesion and stable catalyst performance were achieved in the case of the Ni–Al foam supported catalysts. The Fe–Cr support reacted with the catalytic active components resulting in fast catalyst deactivation. The foam supported catalyst performance was compared with the same catalyst prepared in a form of 0.25mm fraction. Porous supports with different porosities were prepared by the metal foam deformation and the catalyst performance depending on the support porosity (75–95%) was studied. [Copyright &y& Elsevier]

Abstract: Nanocomposite catalysts comprised Ni particles embedded into the complex oxide matrix comprised Y- or Sc-stabilized zirconia (YSZ, ScCeSZ) combined with doped ceria–zirconia oxides or La–Pr–Mn–Cr–O perovskite and promoted by Pt, Pd or Ru were synthesized via different routes (impregnation of YSZ or NiO/YSZ composites with different precursors, one-pot Pechini procedure). Both composition and preparation procedure determining degree of interaction between components of composites were found to strongly affect performance of nanocomposites in steam reforming of methane at short contact times as well as their stability to coking in stoichiometric feeds. Temperature-programmed reduction of composites by CH4 followed by temperature-programmed oxidation by H2O revealed more efficient dissociation of CH4 on promoted composites yielding loose surface CH x species more easily removed by water as compared with unpromoted composites. Best active components highly active and stable to coking were supported as thin layers on different substrates (Ni/YSZ anode platelets, refractory dense/porous metal alloys, cermet or corundum monolithic carriers). These structured catalysts demonstrated high efficiency and stability in the reactions of steam reforming of methane and oxygenates (ethanol, acetone) in pilot-scale reactors. [Copyright &y& Elsevier]

Review: 23 refs. [ABSTRACT FROM AUTHOR]

Review: 70 refs. [ABSTRACT FROM AUTHOR]