Natalia Mezentseva

Nanocomposite Catalysts for Steam Reforming of Methane and Biofuels: Design and Performance

Vladislav Sadykov, Natalia Mezentseva, Galina Alikina, Rimma Bunina, Vladimir Pelipenko, Anton Lukashevich, Zakhar Vostrikov, Vladimir Rogov, Tamara Krieger, Arkady Ishchenko, Vladimir Zaikovsky, Lyudmila Bobrova, Julian Ross, Oleg Smorygo, Alevtina Smirnova, Bert Rietveld and Frans van Berkel, 1Boreskov Institute of Catalysis, Novosibirsk State University, 2University of Limerick, 3Powder Metallurgy Institute, 4Eastern Connecticut State University, 5Energy Research Center of the Netherlands, 1Russia 2Ireland 3Belarus 4USA 5Netherlands

Doped Nanocrystalline Pt-Promoted Ceria-Zirconia as Anode Catalysts for IT SOFC: Synthesis and Properties

Ceria-zirconia samples doped with Gd, Pr, Sm, or La cations were prepared via Pechini route and promoted by Pt. Effect of their real structure and surface properties (characterized by neutronography, EXAFS, XPS, FTIRS of adsorbed CO) on the mobility and reactivity of the lattice oxygen (by oxygen isotope exchange and CH 4 TPR) was analyzed. For the reaction of CH 4 steam reforming (SR), catalytic performance is determined both by Pt dispersion and lattice oxygen mobility. Ni-YSZ anodes promoted by these catalysts possess a stable and efficient performance in CH 4 SR in the 600-800°C range in stoichiometric feeds without coking.

Porous substrates for intermediate temperature SOFCs and in-cell reforming catalysts

Abstract The paper reviews results of development of new composite foam substrates with the graded structure for the intermediate temperature SOFC and structured catalysts of fuels reforming. Ni-Al substrates with porosity of 60-80% were prepared by compressive deformation of open cell metal foams followed by pack aluminizing. Testing in corrosive media revealed advantages of Ni-Al substrates over Fechraloy ones. Button-size thin film solid oxide fuel cell supported on this substrate demonstrated promising performance in the intermediate temperature range. These substrates were shown to be compatible with nanocomposite active components for the fuel reforming comprised of Ni-based alloys strongly interacting with perovskite/fluorite complex oxides with a high oxygen mobility and reactivity. High activity and coking stability of these structured catalysts in steam/autothermal reforming of natural gas, ethanol and acetone was demonstrated without a remarkable impact of heat and mass transfer. A close performance was demonstrated for fuel cells operating on wet H2 or in the mode of internal reforming of natural gas using these catalysts. A concept of the substrate with the graded pore structure and composition was offered.

Metal Supported SOFC on the Gradient Permeable Metal Foam Substrate

Gradient permeable metallic substrate material consisting of two layers of NiAl alloy was developed for the SOFC design. The open-cell foam layer (thickness 1-2 mm, cell density 60 ppi) provides the structure robustness, while a thin (100-200 μm) mesoporous layer facilitates supporting functional layers. Cathode layers (LSM, LSFN and their nanocomposites with GDC or YSZ) and anode layers (NiO/YSZ, NiO/YSZ +Ru/Ln-Sr-Mn-Cr-O nanocomposite catalyst) were deposited by slip casting, electrophoretic deposition or air brushing. Thin (5-10 μm) YSZ layer was deposited by MO CVD. Power density up to 550 mW/cm2 at 700oC was obtained on button-size cells using wet H2-air feeds.

Steam Reforming of Methane on Ru and Pt Promoted Nanocomposites for SOFC Anodes

Nanocomposite cermet materials comprised of NiO/YSZ (20-90 wt. %) co-promoted with SmPrCeZrO or LaPrMnCrO complex oxides and Pt, Pd or Ru were synthesized by Pechini method. These materials were characterized by BET, TEM with EDX, and CH 4 TPR. The catalytic properties were studied for the steam reforming (SR) of CH 4 at short contact times. Factors controlling performance of these composites in CH 4 SR (Ni content, interaction between components in composites as dependent upon their chemical composition) were determined. Ru-promoted composite supported on Ni-Al foam demonstrated a high (up to 75%) methane conversion at 650° in the feed containing 20% CH4 and 40% H 2 O in Ar

Design of Anodes for IT SOFC: Effect of Complex Oxide Promoters and Pd on Activity and Stability in Methane Steam Reforming of Ni/YSZ (ScSZ) Cermets

Effect of fluorite-like or perovskite-like complex oxide promoters and Pd on the performance of Ni/YSZ and Ni/ScSZ cermets in methane steam reforming or selective oxidation by O 2 into syngas at short contact times was studied. Spatial uniformity of dopants distribution in composites was controlled by TEM combined with EDX, while the lattice oxygen mobility and reactivity was elucidated by CH 4 and H 2 TPR. Oxide promoters allow to operate even at stoichiometric H 2 O/CH 4 ratio by suppressing coke deposition through modification of Ni surface, while doping by Pd ensures reasonable performance at moderate (∼550 °C) temperatures required for Intermediate–Temperature Solid Oxide Fuel Cells (IT SOFC).

Ni-loaded nanocrystalline ceria-zirconia solid solutions prepared via modified Pechini route as stable to coking catalysts of CH4 dry reforming

Abstract Mixed nanocrystalline Ce-Zr-O oxides (Ce/Zr = 1 or 7/3) were prepared by modified Pechini route using ethylene glycol solutions of metal salts. Detailed characterization of their real structure and surface properties by X-ray diffraction on synchrotron radiation with the full-profile Rietveld analysis, high resolution electron microscopy with elemental analysis, Raman spectroscopy, UV-Vis and X-ray photoelectron spectroscopy revealed a high homogeneity of cations distribution in nanodomains resulting in stabilization of disordered cubic phase. This provides a high dispersion of NiO loaded on these mixed oxides by wet impregnation, a high reactivity and mobility of oxygen in these catalysts and strong interaction of Ni with support in the reduced state. This helps to achieve a high activity and coking stability of developed catalysts in CH4 dry reforming in feeds with CH4 concentration up to 15% and CH4/CO2 ratio =1.