Oleg Smorygo

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

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.

Advanced Sintering Techniques in Design of Planar IT SOFC and Supported Oxygen Separation Membranes

Thin film solid oxide fuel cells (SOFC) operating in the intermediate temperature (IT) range are now considered as promising for distributed, mobile, standby or auxiliary power generation. At present one of the most important scientific aims in design of solid oxide fuel cells is to lower the operating temperatures to 600-800 С. In this temperature range, majority of problems inherent to SOFC operating at high (950-1000 C) are alleviated. Thus, cations interdiffusion and solid state reactions between electrolyte and electrodes are hampered and thermal stresses are decreased which prevent degradation of the functional layers [Yamamoto, 2004 ]. Hence, design of thin film SOFC requires also elaboration of nanostructured electrodes compatible with electrolytes from chemical and thermophysical points of view and providing a developed three-phase boundary (TPB). In this respect, broad options are provided by design of nanocomposite mixed ionic-electronic conducting (MIEC) functional layers – (Sadykov et al., 2010; Sadykov et al., 2009; Sadykov et al., 2008).

Tailoring properties of reticulated vitreous carbon foams with tunable density

Reticulated vitreous carbon (RVC) foams were manufactured by multiple replications of a polyurethane foam template structure using ethanolic solutions of phenolic resin. The aims were to create an algorithm of fine tuning the precursor foam density and ensure an open-cell reticulated porous structure in a wide density range. The precursor foams were pyrolyzed in inert atmospheres at 700°C, 1100°C and 2000°C, and RVC foams with fully open cells and tunable bulk densities within 0.09–0.42 g/cm3 were synthesized. The foams were characterized in terms of porous structure, carbon lattice parameters, mechanical properties, thermal conductivity, electric conductivity, and corrosive resistance. The reported manufacturing approach is suitable for designing the foam microstructure, including the strut design with a graded microstructure.

Macrocellular vitreous carbon with the improved mechanical strength

Vitreous carbons with regular macrocellular structure, open interconnected porosity, high specific strength and hydraulic permeability were synthesized by infiltration of the epoxy resin into the sacrificial template made from the carbamide granules. Polyvinylpyrrolidone (PVP) solution in ethanol was used as the template binder. When the resin setting and the template extraction had been performed, the resultant porous material was pyrolysed in the nitrogen flow. Depending on PVP concentration in the template binder, final vitreous carbons had the following properties: bulk density at 0.17-0.22 g/cm3; porosity at 85.7%-89.0%; window size at 447-735 µm; Darcian permeability coefficient at (0.64-9.5)×10-9m2; non-Darcian permeability coefficient at (0.53-3.36)×10-4 m. High specific strength of above 8×103 Pa/(kg·m-3) was attained.

Evaluation of SiC–porcelain ceramics as the material for monolithic catalyst supports

Mechanical and thermal properties of SiC-porcelain ceramics were studied in the wide SiC content range of 0–95%. Microstructure evolution, shrinkage at sintering, porosity, mechanical strength, elastic modulus, coefficient of thermal expansion (CTE) and thermal conductivity were studied depending on SiC content. The optimal sintering temperature was 1200 °C, and the maximum mechanical strength corresponded to SiC content of 90%. Parametric evaluation of the ceramic thermal shock resistance revealed its great potential for thermal cycling applications. It was demonstrated that the open-cell foam catalyst supports can be manufactured from SiC-porcelain ceramics by the polyurethane foam replication process.

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

Comparative Studies of Cellular Permeable Solids as Catalyst Supports

Metallic and ceramic foam catalyst supports and catalysts were manufactured. Comparative studies of the foam-structure catalyst supports and straight-channel catalysts supports were performed. Affect of the catalyst support pore structure upon the catalyst operational performance was analyzed.

Integrated Motile Orbital Implants Based on Ceramic Foam Scaffolds: Preparation and In Vivo Study

Zirconia-alumina ceramic foam scaffolds with a nanocrystalline HAP coating were used for the preparation of integrated motile orbital implants. This study demonstrated that open-cell ceramic foams with enhanced strength-to-density ratio are quite suitable as biocompatible materials for the manufacture of orbital implants for post-enucleation syndrome treatment. In-vivo studies demonstrated that the application of a nanocrystallyne (not sintered) HAP coating facilitated the formation of dense fibrous capsule around the implant as well as the fast tissue ingrowth into the implant’s internal space. Orbital implants with the optimized pore size and HAP content were implanted to the animal’s eye cavity with their fixation to the extraocular muscles, and their motility was ensured.