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Sample records for nio ysz operando

  1. Performance evaluation of a fuel cell with NiO-YSV anode operating with natural gas; Avaliacao do desempenho de uma celula a combustivel com anodo de NiO YSZ operando com gas natural

    Energy Technology Data Exchange (ETDEWEB)

    Nobrega, Shayenne Diniz da; Vasconcelos, Carmel Suzarte Ayres; Lima, Luiz Rogerio Pinho de Andrade [Universidade Federal da Bahia (UFBa), Salvador, BA (Brazil). Escola Politecnica. Dept. de Ciencia e Tecnologia dos Materiais]. E-mail: shayennedn@yahoo.com.br

    2008-07-01

    Fuel cell is an electrochemical device that converts the chemical energy into electric energy. The natural gas, for its proven improvement in the income of the equipment in relation to other energy ones, has been very used to feed the solid oxide fuel cell (SOFC) in the generation of electric power. Ceramics of Yttria-stabilized zirconia had been used as electrolyte and when supported with nickel oxide they act as anode in the solid oxide fuel cell, due to raised ionic conductivity that these materials present in high temperatures, while lanthanum with strontium and manganite are used as cathode. In the composition of the anode, the concentration of Ni O, acting as catalytic in the YSZ confers high electric conductivity and high electrochemical activity of the reactions, providing the internal reform in the SOFC. In this work, the solid oxide fuel cell, formed by Yttria- stabilized zirconia, nickel oxide, and lanthanum with strontium and manganite were tested in the reform had been prepared samples of electrode/electrolyte for use in SOFC of the natural gas in the presence of low water text, similar condition to the operation of the SOFC, operating in temperatures range from 700 to 800 deg C. This cell also was characterized using the impedance spectroscopy technique. These results allowed the development of components of the current versus voltage. (author)

  2. LaSrMnO{sub 3} thin films on YSZ/YSZ - NiO by the spin coating method: synthesis and microstructural characterization

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Laurenia Martins Pereira; Souza, Graziele Lopes de [Universidade Federal do Rio Grande do Norte (NUPEG/UFRN), Natal, RN (Brazil). Nucleo de Pesquisa em Petroleo e Gas], Email: lauengmat@hotmail.com; Macedo, Daniel Araujo de; Cela, Beatriz; Paskocimas, Carlos Alberto; Nascimento, Rubens Maribondo do [Universidade Federal do Rio Grande do Norte (PPGCEM/UFRN), Natal, RN (Brazil). Programa de Pos Graduacao em Ciencia e Engenharia de Materiais; Cesario, Moises Romolos [Universidade Federal do Rio Grande do Norte (PPGQ/UFRN), Natal, RN (Brazil). Programa de Pos Graduacao em Quimica

    2010-07-01

    Fuel cells are devices which work by electrochemical mechanism directly converting the chemical energy, by fuel the oxidizing, in electric energy. The Solid Oxide Fuel Cell - SOFC consist an anode, an electrolyte and one cathode made with ceramic materials. The most widely known functional materials used in SOFC are Yttria-stabilized zirconia electrolyte (YSZ), composite anode of YSZ-Ni O and strontium-doped lanthanum manganite cathode (La{sub 1-x}Sr{sub x}MnO{sub 3} - LGSM). In this work the thin films of cathode LSM were deposited by spin coating in a half cell YSZ/YSZ - Ni O. The polymeric resin of 22% strontium-doped lanthanum manganite (LSM 22) was attained by the polymeric precursor method. This resin was directly used for the deposition process. The deposition of 2 or 4 layers occurred by spin coating method with the following conditions: 500 rpm during 15 s and 300 rpm during 40 s. Each layer was thermally treated at 500 deg C for 2 h and heating rate equal to 1 deg C/min. The multi layers were sintered at 1000 deg C for 2 h, heating rate of 3 deg C/min and characterized by X-ray diffraction (XRD) and scanning electronic microscopy (SEM). The LSM 22 thin films presented microstructure with thin particles and thickness of 1 {mu}m. The surface cracks' quantity and size reduction tendency was observed with the increase of the layers deposition number. (author)

  3. Influence of Solution Properties and Process Parameters on the Formation and Morphology of YSZ and NiO Ceramic Nanofibers by Electrospinning

    NARCIS (Netherlands)

    Cadafalch Gazquez, G.; Smulders, V.; Veldhuis, S.A.; Wieringa, P.; Moroni, L.; Boukamp, B.A.; Elshof, ten J.E.

    2017-01-01

    The fabrication process of ceramic yttria-stabilized zirconia (YSZ) and nickel oxide nanofibers by electrospinning is reported. The preparation of hollow YSZ nanofibers and aligned nanofiber arrays is also demonstrated. The influence of the process parameters of the electrospinning process, the phys

  4. In situ X-ray Rietveld analysis of Ni-YSZ solid oxide fuel cell anodes during NiO reduction in H{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Reyes Rojas, A [Centro de Investigacion en Materiales Avanzados SC, Miguel de Cervantes 120, Complejo Industrial Chihuahua, Cd. de Chihuahua, Chihuahua (Mexico); Facultad de Quimica, Universidad Autonoma del Estado de Mexico, Toluca (Mexico); Esparza-Ponce, H E [Centro de Investigacion en Materiales Avanzados SC, Miguel de Cervantes 120, Complejo Industrial Chihuahua, Cd. de Chihuahua, Chihuahua (Mexico); Fuentes, L [Centro de Investigacion en Materiales Avanzados SC, Miguel de Cervantes 120, Complejo Industrial Chihuahua, Cd. de Chihuahua, Chihuahua (Mexico); Lopez-Ortiz, A [Centro de Investigacion en Materiales Avanzados SC, Miguel de Cervantes 120, Complejo Industrial Chihuahua, Cd. de Chihuahua, Chihuahua (Mexico); Keer, A [Centro de Investigacion en Materiales Avanzados SC, Miguel de Cervantes 120, Complejo Industrial Chihuahua, Cd. de Chihuahua, Chihuahua (Mexico); Reyes-Gasga, J [Instituto de Fisica, UNAM. Apartado Postal 20-364. 01000 Mexico DF (Mexico)

    2005-07-07

    A synthesis and characterization of solid oxide fuel cell (SOFC) anodes of nickel with 8%mol yttrium stabilized zirconia (Ni-YSZ) is presented. Attention was focused on the kinetics and phase composition associated with the transformation of NiO-YSZ to Ni-YSZ. The anodes were prepared with an alternative synthesis method that includes the use of nickel acetylacetonate as an inorganic precursor to obtain a highly porous material after sintering at 1400 deg. C and oxide reduction (NiO-YSZ {yields} Ni-YSZ) at 800 deg. C for 8 h in a tubular reactor furnace using 10% H{sub 2}/N{sub 2}. The obtained material was compressed by unidirectional axial pressing into 1 cm-diameter discs with 15-66 wt% Ni and calcinated from room temperature to 800 deg. C. A heating rate of 1 deg. C min{sup -1} showed the best results to avoid any anode cracking. Their structural and chemical characterization during the isothermal reduction were carried out by in situ time-resolved X-ray diffraction, refined with the Rietveld method (which allowed knowing the kinetic process of the reduction), scanning electron microscopy and X-ray energy dispersive spectroscopy. The results showed the formation of tetragonal YSZ 8%mol in the presence of nickel, a decrement in the unit cell volume of Ni and an increment of Ni in the Ni-YSZ anodes during the temperature reduction. The analysis indicated that the Johnson-Mehl-Avrami equation is unable to provide a good fit to the kinetics of the phase transformation. Instead, an alternative equation is presented.

  5. Influence of Solution Properties and Process Parameters on the Formation and Morphology of YSZ and NiO Ceramic Nanofibers by Electrospinning.

    Science.gov (United States)

    Cadafalch Gazquez, Gerard; Smulders, Vera; Veldhuis, Sjoerd A; Wieringa, Paul; Moroni, Lorenzo; Boukamp, Bernard A; Ten Elshof, Johan E

    2017-01-13

    The fabrication process of ceramic yttria-stabilized zirconia (YSZ) and nickel oxide nanofibers by electrospinning is reported. The preparation of hollow YSZ nanofibers and aligned nanofiber arrays is also demonstrated. The influence of the process parameters of the electrospinning process, the physicochemical properties of the spinning solutions, and the thermal treatment procedure on spinnability and final microstructure of the ceramic fibers was determined. The fiber diameter can be varied from hundreds of nanometers to more than a micrometer by controlling the solution properties of the electrospinning process, while the grain size and surface roughness of the resulting fibers are mainly controlled via the final thermal annealing process. Although most observed phenomena are in qualitative agreement with previous studies on the electrospinning of polymeric nanofibers, one of the main differences is the high ionic strength of ceramic precursor solutions, which may hamper the spinnability. A strategy to control the effective ionic strength of precursor solutions is also presented.

  6. Influence of Solution Properties and Process Parameters on the Formation and Morphology of YSZ and NiO Ceramic Nanofibers by Electrospinning

    Directory of Open Access Journals (Sweden)

    Gerard Cadafalch Gazquez

    2017-01-01

    Full Text Available The fabrication process of ceramic yttria-stabilized zirconia (YSZ and nickel oxide nanofibers by electrospinning is reported. The preparation of hollow YSZ nanofibers and aligned nanofiber arrays is also demonstrated. The influence of the process parameters of the electrospinning process, the physicochemical properties of the spinning solutions, and the thermal treatment procedure on spinnability and final microstructure of the ceramic fibers was determined. The fiber diameter can be varied from hundreds of nanometers to more than a micrometer by controlling the solution properties of the electrospinning process, while the grain size and surface roughness of the resulting fibers are mainly controlled via the final thermal annealing process. Although most observed phenomena are in qualitative agreement with previous studies on the electrospinning of polymeric nanofibers, one of the main differences is the high ionic strength of ceramic precursor solutions, which may hamper the spinnability. A strategy to control the effective ionic strength of precursor solutions is also presented.

  7. NiO/YSZ Reduction for SOFC/SOEC Studied In Situ by Environmental Transmission Electron Microscopy

    DEFF Research Database (Denmark)

    Simonsen, Søren Bredmose; Agersted, Karsten; Hansen, Karin Vels

    2014-01-01

    SOFCs/SOECs are typically composed of ceramic materials, which are highly complex at the nano-scale. Scanning and transmission electron microscopy (SEM and TEM) are routinely applied for studying these nano-scaled structures post mortem, but only few SOFC/SOEC studies have applied environmental TEM...... the reduction of NiO/YSZ is slower, which indicates that the presence of YSZ inhibits the reduction of NiO. In the presents in situ experiments the temperature dependent reduction profile are found similar for the both nano-scaled NiO and NiO/YSZ sample. The apparent inhibitive effect of YSZ on NiO reduction...

  8. NiO/YSZ Reduction for SOFC/SOEC Studied In Situ by Environmental Transmission Electron Microscopy

    DEFF Research Database (Denmark)

    Simonsen, Søren Bredmose; Agersted, Karsten; Hansen, Karin Vels;

    2014-01-01

    A typical anode for solid oxide fuel cells (SOFC) or cathode for solid oxide electrolysis cells (SOEC) is a complex porous structure of Ni and yttria-stabilized zirconia (YSZ). The porous Ni/YSZ is usually prepared from powder mixtures of NiO and YSZ, tape casted and sintered into a dense structure....... The study focusses on the temperature dependent dynamical morphology of the NiO/YSZ and on the possible influence of YSZ on the NiO reduction....... and finally reduced during start-up of the SOFC/SOEC in H2 at the operating temperature of the cell (ca. 800 °C). This contribution presents environmental transmission electron microscopy (ETEM) nanoscale observations of the reduction process of a NiO/YSZ powder in H2 at temperatures up to almost 1000 °C...

  9. SOFC mini-tubulares basadas en YSZ

    Directory of Open Access Journals (Sweden)

    Campana, R.

    2008-08-01

    ódico (5, 10, 100%vol y aire para el cátodo. Los cátodos empleados son pintura de Pt o capas de LSF (con YSZ o SDC de entre 20-50μm. Los OCV medidos ajustan con la predicción prevista de la ley de Nernst lo que indica que las capas de YSZ son estancas al paso de gas. Las curvas I-V muestran una corriente eléctrica máxima próxima a 500mW/cm2 operando a 850ºC. También se han realizado medidas de impedancia compleja para determinar la resistencia de los diversos componentes de la pila.

  10. Comparison of the Degradation of the Polarisation Resistance of Symmetrical LSM-YSZ cells, with Anode Supported Ni-YSZ/YSZ/LSM-YSZ SOFCs

    DEFF Research Database (Denmark)

    Torres da Silva, Iris Maura; Nielsen, Jimmi; Hjelm, Johan;

    2009-01-01

    Impedance spectra of a symmetrical cell with SOFC cathodes (LSM-YSZ/YSZ/LSM-YSZ) and an anode supported planar SOFC (Ni-YSZ/YSZ/LSM-YSZ) were collected at OCV at 650{degree sign}C in air (cathode) and humidified (4%) hydrogen (anode), over 155 hours. The impedance was affected by degradation over...

  11. Interaction of NiO with yttria-stabilized zirconia

    DEFF Research Database (Denmark)

    Kuzjukevics, A.; Linderoth, Søren

    1997-01-01

    As-prepared and heat treated plasma-produced 8 and 10 mol% yttria-stabilized zirconia (YSZ) powders doped with 0, 5, 10 and 75 mol% NiO have been investigated by XRD. The as-prepared powders are mixtures of metastable tetragonal and cubic phases but they transform to a single YSZ phase upon heat...... treatment above 1200 degrees C. The solubility of NiO in yttria-stabilized zirconia is less than 2 mol% at 1600 degrees C and varies little within the investigated yttria concentration range. The solubility increases with increasing temperature and the total NiO concentration. The activation energy...

  12. Tailoring the Microstructure of a Solid Oxide Fuel Cell Anode Support by Calcination and Milling of YSZ

    Science.gov (United States)

    Hanifi, Amir Reza; Laguna-Bercero, Miguel A.; Sandhu, Navjot Kaur; Etsell, Thomas H.; Sarkar, Partha

    2016-06-01

    In this study, the effects of calcination and milling of 8YSZ (8 mol% yttria stabilized zirconia) used in the nickel-YSZ anode on the performance of anode supported tubular fuel cells were investigated. For this purpose, two different types of cells were prepared based on a Ni-YSZ/YSZ/Nd2NiO4+δ-YSZ configuration. For the anode preparation, a suspension was prepared by mixing NiO and YSZ in a ratio of 65:35 wt% (Ni:YSZ 50:50 vol.%) with 30 vol.% graphite as the pore former. As received Tosoh YSZ or its calcined form (heated at 1500 °C for 3 hours) was used in the anode support as the YSZ source. Electrochemical results showed that optimization of the fuel electrode microstructure is essential for the optimal distribution of gas within the support of the cell, especially under electrolysis operation where the performance for an optimized cell (calcined YSZ) was enhanced by a factor of two. In comparison with a standard cell (containing as received YSZ), at 1.5 V and 800 °C the measured current density was -1380 mA cm-2 and -690 mA cm-2 for the cells containing calcined and as received YSZ, respectively. The present study suggests that the anode porosity for improved cell performance under SOEC is more critical than SOFC mode due to more complex gas diffusion under electrolysis mode where large amount of steam needs to be transfered into the cell.

  13. Operando fuel cell spectroscopy

    Science.gov (United States)

    Kendrick, Ian Michael

    The active state of a catalyst only exists during catalysis (1) provided the motivation for developing operando spectroscopic techniques. A polymer electrolyte membrane fuel cell (PEMFC) was designed to interface with commercially available instruments for acquisition of infrared spectra of the catalytic surface of the membrane electrode assembly (MEA) during normal operation. This technique has provided insight of the complex processes occurring at the electrode surface. Nafion, the solid electrolyte used in most modern-day polymer electrolyte membrane fuel cells (PEMFC), serves many purposes in fuel cell operation. However, there is little known of the interface between Nafion and the electrode surface. Previous studies of complex Stark tuning curves of carbon monoxide on the surface of a platinum electrode were attributed the co-adsorption of bisulfite ions originating from the 0.5M H2SO4 electrolyte used in the study(2). Similar tuning curves obtained on a fuel cell MEA despite the absence of supplemental electrolytes suggest the adsorption of Nafion onto platinum (3). The correlation of spectra obtained using attenuated total reflectance spectroscopy (ATR) and polarization modulated IR reflection-absorption spectroscopy (PM-IRRAS) to a theoretical spectrum generated using density functional theory (DFT) lead to development of a model of Nafion and platinum interaction which identified participation of the SO3- and CF3 groups in Nafion adsorption. The use of ethanol as a fuel stream in proton exchange membrane fuel cells provides a promising alternative to methanol. Relative to methanol, ethanol has a greater energy density, lower toxicity and can be made from the fermentation of biomass(4). Operando IR spectroscopy was used to study the oxidation pathway of ethanol and Stark tuning behavior of carbon monoxide on Pt, Ru, and PtRu electrodes. Potential dependent products such as acetaldehyde, acetic acid and carbon monoxide are identified as well as previously

  14. Continuum mechanics simulations of NiO/Ni-YSZ composites during reduction and re-oxidation

    DEFF Research Database (Denmark)

    Pihlatie, Mikko; Frandsen, Henrik Lund; Kaiser, Andreas;

    2010-01-01

    for the dimensional change arises from the volumetric change related to the phase change NiO ↔ Ni. The measurable change in bulk length is given by the ceramic YSZ backbone as a response to the stress created by the chemical strain. The different subprocesses described in the model for YSZ were elastic and anelastic...... expansion, diffusional creep, grain boundary sliding (GBS) and microcracking due to excessive stress. In the Ni/NiO phase, nonelastic strains in terms of diffusional and power law creep were implemented, and additionally for NiO deformation due to microcracking and/or pseudoplasticity. Semi......-empirical correlations were employed for creep limiting grain growth of Ni and NiO, particle coarsening of Ni and particle growth in NiO during the oxidation. Seven experimental cases of high temperature redox dilatometry were simulated. The model shows good qualitative agreement with the measurements. The different...

  15. Operando research in heterogeneous catalysis

    CERN Document Server

    Groot, Irene

    2017-01-01

    This book is devoted to the emerging field of techniques for visualizing atomic-scale properties of active catalysts under actual working conditions, i.e. high gas pressures and high temperatures. It explains how to understand these observations in terms of the surface structures and dynamics and their detailed interplay with the gas phase. This provides an important new link between fundamental surface physics and chemistry, and applied catalysis. The book explains the motivation and the necessity of operando studies, and positions these with respect to the more traditional low-pressure investigations on the one hand and the reality of industrial catalysis on the other. The last decade has witnessed a rapid development of new experimental and theoretical tools for operando studies of heterogeneous catalysis. The book has a strong emphasis on the new techniques and illustrates how the challenges introduced by the harsh, operando conditions are faced for each of these new tools. Therefore, one can also read th...

  16. An operando surface enhanced Raman spectroscopy (SERS) study of carbon deposition on SOFC anodes.

    Science.gov (United States)

    Li, Xiaxi; Liu, Mingfei; Lee, Jung-pil; Ding, Dong; Bottomley, Lawrence A; Park, Soojin; Liu, Meilin

    2015-09-07

    Thermally robust and chemically inert Ag@SiO2 nanoprobes are employed to provide the surface enhanced Raman scattering (SERS) effect for an in situ/operando study of the early stage of carbon deposition on nickel-based solid oxide fuel cell (SOFC) anodes. The enhanced sensitivity to carbon enables the detection of different stages of coking, offering insights into intrinsic coking tolerance of material surfaces. Application of a thin coating of gadolinium doped ceria (GDC) enhances the resistance to coking of nickel surfaces. The electrochemically active Ni-YSZ interface appears to be more active for hydrocarbon reforming, resulting in the accumulation of different hydrocarbon molecules, which can be readily removed upon the application of an anodic current. Operando SERS is a powerful tool for the mechanistic study of coking in SOFC systems. It is also applicable to the study of other catalytic and electrochemical processes in a wide range of conditions.

  17. Microwave processing: A potential technique for preparing NiO–YSZ composite and Ni–YSZ cermet

    Indian Academy of Sciences (India)

    Kanchan Lata Singh; Ajay Kumar; Anirudh P Singh; S S Sekhon

    2008-08-01

    In the present study, microwave energy (2.45 GHz) has been used to prepare nickel oxide–yttria stabilized zirconia (NiO–YSZ) composites of composition, NiO–(1 – ) Zr0.9Y0.1O1.95 ( = 0.2, 0.3, 0.4, 0.5 and 0.6), from a precursor obtained by mixing NiO, Y2O3 and monoclinic ZrO2 in their stoichiometric ratio. The composites have been prepared by conventional processing also to compare the products with those of microwave processed products. During comparison, it was observed that NiO–YSZ composites of each composition obtained by microwave processing had cubic phase of YSZ while in the conventionally prepared composites of compositions, = 0.2 and 0.3, monoclinic, tetragonal and cubic phases of zirconia existed instead of its pure cubic phase. The composites were reduced to yield Ni–YSZ.

  18. NiO/YSZ nanocomposite particles synthesized via co-precipitation method for electrochemically active Ni/YSZ anode

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Kazuyoshi; Okamoto, Go; Naito, Makio; Abe, Hiroya [Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan)

    2009-08-01

    NiO/YSZ composite particles were synthesized via a co-precipitation of hydroxides. We investigated the effect of pH on the morphology of the composite particles, as well as on the microstructure and the electrochemical property of the Ni/YSZ anode. The particles synthesized at pH 10 involved aggregated composites and large NiO. The particles resulted in coarse and inhomogeneous anode microstructure and moderate area specific resistance (ASR) as 0.57 {omega} cm{sup 2} at 800 C under open circuit voltage (OCV). Contrarily, nano-sized composite particles were successfully synthesized at pH 13. The particles provided fine as well as homogeneous porous structure with the grain size in the range 200-400 nm and low ASR as 0.36 {omega} cm{sup 2} at 800 C under OCV. (author)

  19. Mechanical properties of NiO/Ni-YSZ composites depending on temperature, porosity and redox cycling

    DEFF Research Database (Denmark)

    Pihlatie, Mikko; Kaiser, Andreas; Mogensen, Mogens Bjerg

    2009-01-01

    with the Neel temperature, 250 degrees C, of NiO was observed. Above this temperature, a linear decrease occurred. Specific damping showed a peak at 170-180 degrees C and increased above ca. 1000 degrees C in NiO-YSZ. In the reduced state the elastic modulus decreased linearly with temperature; specific damping......The Impulse Excitation Technique (IET) was used to determine the elastic modulus and specific damping of different Ni/NiO-YSZ composites suitable for use in solid oxide fuel cells (SOFC). The porosity of the as-sintered samples varied from 9 to 38% and that of the reduced ones from 31 to 52...

  20. In situ surface reduction of a NiO-YSZ-alumina composite using scanning probe microscopy

    DEFF Research Database (Denmark)

    Hansen, Karin Vels; Jacobsen, Torben; Thydén, Karl Tor Sune

    2014-01-01

    In situ surface reductions of NiO-YSZ-Al2O3 composites into Ni-YSZ-Al2O3 cermets were carried out at 312–525 °C in a controlled atmosphere high-temperature scanning probe microscope (CAHT-SPM) in dry and humidified 9 % H2 in N2. The reduction of NiO was followed by contact mode scanning...... dependent and followed the Arrhenius equation. For samples reduced in dry hydrogen, the Arrhenius plot showed two regions with different activation energies. Scanning electron microscopy confirmed a difference in microstructure between these temperature regimes. A strong retarding effect of steam (H2O...

  1. Executable choreographies applied in OPERANDO

    Directory of Open Access Journals (Sweden)

    Sinica Alboaie

    2016-12-01

    Full Text Available The objective of this paper is to present the software architecture used for the OPERANDO privacy platform, funded by the European Union in a Horizon 2020 project. For integration, OPERANDO is using SwarmESB, an open source Enterprise Service Bus (ESB based on executable choreographies. In this paper we are presenting the concept of service transformations, presented as a bridge between the world of REST web services and the world of services implemented with executable choreographies. These transformations are improving the heterogeneity aspects when we are analysing SwarmESB as a distributed system. Five types of transformations that have been analysed and implemented as open source software have been integrated. This proposal is shaped around a common language capable of expressing all these five transformation types we have identified working for OPERANDO. Therefore, the Domain Specific Language proposed, renders the essential elements for transformations among functions, web services and executable choreographies. This unification will trigger a quantitative effect on the productivity of the teams creating or integrating web services in a federated service bus environment which is a key architectural component in the future Internet-of-Things and cloud systems.

  2. Solid oxide fuel cell anode surface modification by magnetron sputtering of NiO/YSZ thin film

    Science.gov (United States)

    Solovyev, A. A.; Shipilova, A. V.; Ionov, I. V.; Smolyanskiy, E. A.; Lauk, A. L.; Kovalchuk, A. N.; Remnev, G. E.; Lebedynskiy, A. M.

    2017-05-01

    NiO/ZrO2-Y2O3 (NiO/YSZ) anode functional layers (AFL) with 16-60 vol.% of NiO were deposited onto NiO/YSZ anode substrates by magnetron sputtering, followed by annealing in air at 1200 °C. The optimal deposition conditions for NiO/YSZ were determined. NiO content in the films was varied by changing the oxygen flow rate during the sputtering process. The microstructure and phase composition of NiO/YSZ anode functional layer were studied by SEM and XRD methods. Anode functional layers were fully crystallized and comprised of grains up to 500 nm in diameter after reduction in hydrogen. Anode-supported solid oxide fuel cells (SOFC) with the diameter of 20 mm including the magnetron sputtered AFL, 4-microns thick YSZ electrolyte and La0.6Sr0.4Co0.2Fe0.8O3/Ce0.9Gd0.1O2 (LSCF/CGO) cathode were fabricated and tested. Electrochemical properties of the single fuel cells were investigated as a function of NiO volume content in AFL and AFL thickness.

  3. The crystal structure and morphology of NiO-YSZ composite that prepared from local zircon concentrate of Bangka Island

    Energy Technology Data Exchange (ETDEWEB)

    Rahmawati, F., E-mail: fitria@mipa.uns.ac.id; Apriyani, K.; Heraldy, E. [Research Group of Solid State Chemistry & Catalysis, Department of Chemistry, Sebelas Maret University, Jl. Ir. Sutami 36A Kentingan Surakarta (Indonesia); Soepriyanto, S. [Department of Metallurgical Engineering, Faculty of Mining and Petroleum Engineering, Institut Teknologi Bandung, Jl. Ganesha 10 Bandung 40132 (Indonesia)

    2016-03-29

    In order to increase the economic value of local zircon concentrate from Bangka Island, NiO-YSZ was synthesized from Zirconia, ZrO{sub 2} that was prepared from local zircon concentrate. The NiO-YSZ composite was synthesized by solid state reaction method. XRD analysis equipped with Le Bail refinement was carried out to analyze the crystal structure and cell parameters of the prepared materials. The result showed that zirconia was crystallized in tetragonal structure with a space group of P42/NMC. Yttria-Stabilized-Zirconia (YSZ) was prepared by doping 8% mol yttrium oxide into zirconia and then sintered at 1250°C for 3 hours. Doping of 8% mol Yttria allowed phase transformation of zirconia from tetragonal into the cubic structure. Meanwhile, the composite of NiO-YSZ consists of two crystalline phases, i.e. the NiO with cubic structure and the YSZ with cubic structure. SEM analysis of the prepared materials shows that the addition of NiO into YSZ allows the morphology to become more roughness with larger grain size.

  4. Polarization Induced Changes in LSM Thin Film Electrode Composition Observed by In Operando Raman Spectroscopy and TOF-SIMS

    DEFF Research Database (Denmark)

    McIntyre, Melissa D.; Walker, Robert; Traulsen, Marie Lund

    2015-01-01

    an applied potential.1-3 The presented work explores the polarisation induced changes in LSM electrode composition by utilizing in operando Raman spectroscopy and post mortem ToF-SIMS depth profiling on LSM thin film model electrodes fabricated by pulsed laser deposition on YSZ substrates with a thin (200 nm...... recorded through the LSM thin film electrodes and revealed distinct compositional changes throughout the electrodes (Figure 2). The electrode elements and impurities separated into distinct layers that were more pronounced for the stronger applied polarisations. The mechanism behind this separation...

  5. Improvement in SOFC anode performance by finely-structured Ni/YSZ cermet prepared via heterocoagulation.

    Science.gov (United States)

    Sunagawa, Yoji; Yamamoto, Katsutoshi; Muramatsu, Atsushi

    2006-03-30

    A novel preparation technique for a nanostructured anode for a solid oxide fuel cell is investigated. By mixing nanometer-sized NiO and YSZ powders in a pH-controlled aqueous media, a fine mixture of nanoparticles is successfully obtained through heterocoagulation. The anode prepared from thus prepared mixture has a large triple phase boundary and shows a great improvement in the anode performance by increasing the electric conductivity and effective surface area.

  6. The Ni-YSZ interface

    DEFF Research Database (Denmark)

    Jensen, Karin Vels

    The anode/electrolyte interface in solid oxide fuel cells (SOFC) is known to cause electrical losses. Geometrically simple Ni/yttria-stabilised zirconia (YSZ) interfaces were examined to gain information on the structural and chemical changes occurring during experiments at 1000°C in an atmosphere...... content (99.8% Ni and 99.995% Ni) were used to examine the impact of impurities on the polarisation resistance and contact area morphology. The electropolished nickel wires were pressed against a polished 8 mol% YSZ surface. Extensive structural changes from a flat interface to a hill and valley structure...... between polarised and non-polarised samples. With pure nickel wires, however, the microstructures depended on the polarisation/non-polarisation conditions. At non-polarised conditions a hill and valley type structure was found. Anodic polarisation produced an up to 1 μm thick interface layer consisting...

  7. Synergistic effects of Ni 1- xCo x-YSZ and Ni 1- xCu x-YSZ alloyed cermet SOFC anodes for oxidation of hydrogen and methane fuels containing H 2S

    Science.gov (United States)

    Grgicak, Catherine M.; Pakulska, Malgosia M.; O'Brien, Julie S.; Giorgi, Javier B.

    Preparation and performance of bimetallic Ni (1- x)Co x-YSZ and Ni (1- x)Cu x-YSZ anodes were tested to overcome common deficiencies of carbon and sulfur poisoning in SOFCs. Ni 1- xCo xO-YSZ and Ni (1- x)Cu xO-YSZ precursors were synthesized via co-precipitation of their respective chlorides. Single cell solid oxide fuel cells of these bimetallic anodes were tested in H 2, CH 4, and H 2S/CH 4 fuel mixtures. Addition of Cu 2+ into the NiO lattice resulted in large metal particle sizes and decreased SOFC performance. Addition of Co 2+ into the NiO lattice to form Ni 0.92Co 0.08O-YSZ anode precursor produced a cermet with a large BET surface area and active metal surface area, thus increasing the rate of hydrogen oxidation for this sample. The performance of both bimetallics was found to quickly degrade in dry CH 4 due to carbon deposition and lifting of the anode from the electrolyte. However, Ni 0.69Co 0.31-YSZ showed superior activity in a 10% (v/v) H 2S/CH 4 fuel mixture, surpassing performance with H 2 fuel, thereby demonstrating the exciting prospect of using sulfidated Ni (1- x)Co x-YSZ as SOFC anodes in sulfur containing methane streams. The active anode becomes a sulfidated alloy (Ni-Co-S) under operating conditions. This anode showed enhanced performance, which surpassed those of sulfidated Ni and Co anodes, thereby suggesting a synergistic behaviour in the Ni-Co-S anode.

  8. Electrochemical reduction of NiO in a composite electrode

    DEFF Research Database (Denmark)

    Hu, Qiang; Jacobsen, Torben; Hansen, Karin Vels;

    2013-01-01

    Electrochemical reduction of NiO in a composite electrode along with 8 mol% Y2O3 stabilized zirconia (8YSZ) is studied. Voltage sweeps are performed on cells with a counter electrode made from Pt or the composite of (La0.75Sr0.25)0.95MnO 3 ± δ (LSM25) and 8YSZ, but the composite electrode gives...... increases, hereafter a decay is observed. The kinetics of electrochemical reduction of NiO can be described by the Avrami equation. In performed experiments the exponent of the Avrami equation is in the range of 0.5-0.7 and the overall rate constant varies from 1.19 to 7.73 × 10- 3 and increases...

  9. Effect of Paste Composition on the Microstructure of NiO Electrode%浆料成分对NiO电极微观结构的影响

    Institute of Scientific and Technical Information of China (English)

    王敏; 夏风; 王晓昳; 鄢文超; 肖建中

    2012-01-01

    NiO paste, Ni paste and Ni/YSZ paste were used to prepare NiO sensing electrodes, respectively. Ni/YSZ paste was fabricated by adding 15 vol% YSZ powder into Ni paste. The results indicated that the NiO electrodes made by NiO paste using ordinary sintering are compact and contained a lot of cracks. By contrast, the NiO electrodes and NiO/YSZ composite electrodes prepared by Ni paste and Ni/YSZ paste adopting reaction sintering, respectively, are porous and no cracks are observed. The addition of YSZ in pastes have a strong particle refining effect on NiO grains, enhance interface adhesion between NiO electrode and YSZ electrolyte and increase the amount and length of three phase boundary.%分别采用NiO浆料、Ni浆料和Ni/YSZ浆料制备NiO敏感电极.其中Ni/YSZ浆料是由在Ni浆料中添加15vol% YSZ粉末制备的.结果表明,采用NiO浆料普通烧结得到的NiO电极致密且有裂纹;采用Ni浆料和Ni/YSZ浆料反应烧结分别制备的NiO电极和NiO/YSZ复合电极则疏松多孔且无裂纹.浆料中添加的YSZ不仅能够细化NiO电极晶粒,同时能增强电极和基底的界面附着,增加三相界面的数量和长度.

  10. Research on sintering process of YSZ electrolyte

    Institute of Scientific and Technical Information of China (English)

    HAN Minfang; TANG Xiuling; PENG Suping

    2006-01-01

    Yttria stabilized zirconia (YSZ) has widely been used as electrolyte in solid oxide fuel cell (SOFC).The microstructure of YSZ related to the fabrication process was discussed in the paper.With YSZ nano-powders about 40-100 nm as raw material, the YSZ adobe was manufactured by tape calendering process.The named three-step sintering process was performed at 1000 ℃ for 2 h, then raised the temperature with normal rate and as soon as up to 1400 ℃, the furnace was controlled at 1250-1300 ℃ for 10-20 h.The high dense YSZs with the relative density of 96%-99% were obtained; the grain size of YSZ could be reduced to 0.5-3 μm.The above result is benefited to co-fired in the electrode-supported SOFCs.

  11. Dynamics of the YSZ-Pt Interface

    DEFF Research Database (Denmark)

    Bay, Lasse; Jacobsen, Torben

    1997-01-01

    Yttria stabilized zirconia (YSZ)-Pt point electrodes were examined by linear potential sweep, potential step and impedance measurements at 1000 degrees C in air. Inductive loops and hysteresis phenomena with long relaxation times were found. Atomic force microscopy showed changes of the interface...... between Pt and YSZ induced by the current passage. These changes involve transport of solid and are slow enough to explain the large time constants. The low frequency capacitance and inductive loop forming an entire circle indicate the presence of gas reservoirs at the YSZ-Pt interface....

  12. Investigation on microstructures of NiO-YSZ composite and Ni-YSZ cermet for SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Talebi, Tahereh; Sarrafi, Mohammad Hassan; Haji, Mohsen; Raissi, Babak; Maghsoudipour, Amir [Materials and Energy Research Center, Karaj, Tehran 14155-4777 (Iran)

    2010-09-15

    NiO-YSZ composites and Ni-YSZ cermets were successfully performed for solid oxide fuel cell applications. These composites must have enough porosity and appropriate microstructure for transferring the fuel gases. In this study, ball-milling was used as a simple, cost-effective method for the purpose of mixing the raw materials. The homogeneity of NiO-YSZ composites was examined by Map mode of SEM. NiO-YSZ composites were reduced at the high temperature under the controlled atmosphere to fabricate Ni-YSZ cermet. Variations in the anode phases were investigated by XRD and microstructure and porosity of composites were observed by SEM. Effective parameters like temperatures and the amount of pore former were investigated on open porosity, bulk density, electrical conductivity as well as electrochemical impedance of NiO-YSZ composites and Ni-YSZ cermet. A thin layer of YSZ was deposited by EPD as an electrolyte on NiO-YSZ composites which had various amount of open porosity, to study its effect on the performance of semi-cells by electrochemical impedance. (author)

  13. Femtosecond laser additive manufacturing of YSZ

    Science.gov (United States)

    Liu, Jian; Bai, Shuang

    2017-04-01

    Laser additive manufacturing (LAM) of Yttria-Stabilized Zirconia (YSZ) is investigated using femtosecond (fs) fiber lasers. Various processing conditions are studied, which leads to desired characteristics in terms of morphology, porosity, hardness, microstructural and mechanical properties of the processed components. High-density (>99%) YSZ part with refined grain and increased hardness was obtained. Microstructure features of fabricated specimens were studied with SEM, EDX, the measured micro hardness is achieved as high as 18.84 GPa.

  14. Femtosecond laser additive manufacturing of YSZ

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jian; Bai, Shuang [PolarOnyx, Inc., San Jose, CA (United States)

    2017-04-15

    Laser additive manufacturing (LAM) of Yttria-Stabilized Zirconia (YSZ) is investigated using femtosecond (fs) fiber lasers. Various processing conditions are studied, which leads to desired characteristics in terms of morphology, porosity, hardness, microstructural and mechanical properties of the processed components. High-density (>99%) YSZ part with refined grain and increased hardness was obtained. Microstructure features of fabricated specimens were studied with SEM, EDX, the measured micro hardness is achieved as high as 18.84 GPa. (orig.)

  15. LSM-YSZ Reactions in Different Atmospheres

    DEFF Research Database (Denmark)

    Chen, Ming; Liu, Yi-Lin; Hagen, Anke

    2009-01-01

    results in a decomposition of the formed La- and Sr-zirconates. The de-stabilisation of the LSM-YSZ interface under long-term annealing at 1,000 °C originates mainly from the inter-diffusion across the interface. Under reduced P(O2), the Mn diffusion from LSM into YSZ is enhanced. High P(O2) (0.21 atm...

  16. Kinetics and mechanisms for the adsorption, dissociation, and diffusion of hydrogen in Ni and Ni/YSZ slabs: a DFT study.

    Science.gov (United States)

    Weng, Meng Hsiung; Chen, Hsin-Tsung; Wang, Yao-Chun; Ju, Shin-Pon; Chang, Jee-Gong; Lin, M C

    2012-04-03

    The adsorption, dissociation, and diffusion of hydrogen in Ni(100) and Ni(100)/YSZ(100) slabs with two different interfaces (Ni/cation and Ni/O interface) have been studied by the density functional theory (DFT) with the Perdew-Wang functional. The H(2) molecule is found to preferentially absorb on a Top (T) site with side-on configuration on the Ni(100) surface, while the H-atom is strongly bound at a fcc Hollow (H) site. The barrier for the H(2) dissociation on both surfaces is calculated to be only ~0.1 eV. The potential energy pathways of H diffusion on pure Ni and Ni/YSZ with the two different interfaces are studied. Our calculated results show that the H-atom diffusion occurs via surface path rather than the bulk path. For the bulk path in Ni/YSZ, H-atom migration can occur more readily at the Ni/cation interface compared to the Ni/O interface. The existence of vacancy in the interface region is found to improve the mobility of H-atoms at the interface of Ni/YSZ slab. The rate constants for hydrogen dissociation and diffusion in pure Ni and Ni/YSZ are predicted.

  17. Influence of reduction conditions of NiO on its mechanical and electrical properties

    Directory of Open Access Journals (Sweden)

    Yehor Brodnikovskyi

    2016-04-01

    Full Text Available Yttria stabilized zirconia with a nickel catalyst (Ni-YSZ is the most developed, widely used cermet anode for manufacturing Solid Oxide Fuel Cells (SOFCs. Its electro-catalytic properties, mechanical durability and performance stability in hydrogen-rich environ­ments makes it the state of the art fuel electrode for SOFCs. During the reduction stage in initial SOFC operation, the virgin anode material, a NiO-YSZ mixture, is reduced to Ni-YSZ. The volume decrease associated with the change from NiO-YSZ to Ni-YSZ creates voids and causes structural changes, which can influence the physical properties of the anode. In this work, the structural, mechanical and electrical properties of NiO samples before and after reduction in pure H2 and a mixture of 5 vol. % H2-Ar were studied. The NiO to Ni phase transformations that occur in the anode under reducing and Reduction-Oxidation (RedOx cycling conditions and the impact on cell microstruc­ture, strength and electrical conductivity have been examined. Results show that the RedOx treatment of the NiO samples influence on their properties controversially, due to structural transfor­mation (formation of large amount of fine pores of the reduced Ni. It strengthened the treated samples yielding the highest mechanical strength values of 25.7 MPa, but from another side it is resulting in lowest electrical conductivity value of 1.9×105 S m-1 among all reduced samples. The results of this investigation shows that reduction conditions of NiO is a powerful tool for influence on properties of the anode substrate.

  18. Electrophoretic deposition of 9-YSZ solid electrolyte on Ni- YSZ composite; Estudos de deposicao eletroforetica de ceramicas de 9-YSZ sobre Ni-YSZ

    Energy Technology Data Exchange (ETDEWEB)

    Santos, F.S.; Yoshito, W.K.; Lazar, D.R.R.; Ussui, V., E-mail: vussui@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (CCTM/IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Ciencia e Tecnologia de Materiais

    2010-07-01

    9-YSZ ceramic and Ni-YSZ metal/ceramic composite are the more commonly used materials for the fabrication of solid oxide fuel cell electrolyte and anode, respectively. The main challenges for these applications are the forming of both materials as superposed double thin layers. In the present work ceramic powder of 9- YSZ was synthesized by a coprecipitation technique and the Ni O-YSZ composite by a combustion technique. The later was formed by uniaxial pressing as cylindrical pellets of 15 mm diameter. Thin ceramic layers of 9-YSZ were deposited on composite pellets from a suspension with 10% solid content by an Electrophoretic Deposition technique. Applied voltage varied in the range of 30 to 200 V and deposition time from 15 to 90 seconds, evaluating the deposited mass, porosity on the interface and adhesion of layers. Resulted ceramics were characterized by X-ray diffraction and were observed in a scanning electron microscope. Results showed that deposited layers are thin ({approx}20{mu}m), dense and have good adhesion on the surface of composite substrate. (author)

  19. Effect of YSZ sintering temperature on mixed potential sensor performance

    Energy Technology Data Exchange (ETDEWEB)

    Sekhar, Praveen K [Los Alamos National Laboratory; Brosha, Eric L [Los Alamos National Laboratory; Rangachary, Mukundan [Los Alamos National Laboratory; Garzon, Fernando H [Los Alamos National Laboratory; Nelson, Mark A [Los Alamos National Laboratory; Toracco, Dennis [Los Alamos National Laboratory

    2009-01-01

    In this article, the influence of Yttria-Stabilized Zirconia (YSZ) sintering temperature on a Pt/YSZ/La{sub 0.8}Sr{sub 0.2}CrO{sub 3} mixed potential sensor performance is reported. The sintering temperature of YSZ was varied from 1000 to 1200 C. Mercury porosity measurements were performed to estimate the porosity and tortuosity of the YSZ sample as a function of sintering temperature. Further, the surface area of YSZ was computed by the BET method. After YSZ characterization, the unbiased and biased sensor response was recorded. The 1000 C sintered YSZ sample was taken as the reference for comparison purposes. Experimental results indicated a 30% reduction in porosity for the 1200 C sintered YSZ sample, accounting for a 14-fold increase in the sensor response rise time. In addition, for the same sample, a 13-fold increase in sensitivity was observed upon exposure to propylene (100 ppm), associated with a 76% reduction in surface area. The slow response time of the sensor with YSZ sintered at higher temperatures has been attributed to higher tortuosity (delay in gas permeation to the three phase interface). Whereas, reduced heterogeneous catalysis induced by lower surface area accounts for the rise in sensitivity levels. The optimum YSZ sintering temperature was found to lie between 1100 and 1150 C.

  20. Microstructural and chemical changes at the Ni/YSZ interface

    DEFF Research Database (Denmark)

    Hansen, Karin Vels; Primdahl, Søren; Chorkendorff, Ib

    2001-01-01

    A bent nickel wire was pressed against a yttria-stabilised zirconia (YSZ) surface, creating a small contact area. The Ni/YSZ interface was investigated and characteristic microstructures were found to develop during 200-300 h heat treatment at 1000 degreesC in 97% H-2/3% H2O with and without pola...... contact area on the YSZ developed a hill and valley structure with an amplitude of 100 nm. The nickel wires showed negative imprints of the YSZ structures. (C) 2001 Elsevier Science B.V. All rights reserved....

  1. In situ redox cycle of a nickel-YSZ fuel cell anode in an environmental transmission electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Jeangros, Q. [Interdisciplinary Center for Electron Microscopy, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Faes, A. [Interdisciplinary Center for Electron Microscopy, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland)] [Laboratory of Industrial Energy Systems, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Wagner, J.B.; Hansen, T.W. [Center for Electron Nanoscopy, Technical University of Denmark, DK-2800 Kongens Lyngby (Denmark); Aschauer, U. [Chemistry Department, Princeton University, Princeton, NJ 08544 (United States); Van herle, J. [Laboratory of Industrial Energy Systems, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Hessler-Wyser, A., E-mail: aicha.hessler@epfl.ch [Interdisciplinary Center for Electron Microscopy, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Dunin-Borkowski, R.E. [Center for Electron Nanoscopy, Technical University of Denmark, DK-2800 Kongens Lyngby (Denmark)

    2010-08-15

    Environmental transmission electron microscopy is used in combination with density functional theory calculations to study the redox stability of a nickel/yttria-stabilized zirconia solid oxide fuel cell anode. The results reveal that the transfer of oxygen from NiO to yttria-stabilized zirconia triggers the reduction reaction. During Ni reoxidation, the creation of a porous structure, due to mass transport, accounts for the redox instability of the Ni-based anode. Both the expansion of NiO during a redox cycle and the presence of stress in the yttria-stabilized zirconia grains are observed directly. Besides providing an understanding of the Ni-YSZ anode redox degradation, the observations are used to propose an alternative anode design for improved redox tolerance.

  2. COMPARISON OF THERMAL SHOCK BEHAVIOR OF 7YSZ, 15YSZ AND SYSZ THERMAL BARRIER COATINGS PRODUCED BY APS METHOD

    Directory of Open Access Journals (Sweden)

    H. Jamali

    2016-07-01

    Full Text Available Nanostructured scandia, yttria doped zirconia (SYSZ, 7wt. % yttria stabilized zirconia (7YSZ and 15YSZ thermal barrier coatings (TBCs were produced by plasma spraying on nickel-based superalloy substrates with NiCrAlY as the bond coat. The thermal shock behavior of the three as-sprayed TBCs at 1000 °C was investigated. The results indicated that the thermal cycling lifetime of SYSZ and 7YSZ TBCs was longer than the 15YSZ TBCs due to the lower thermal mismatch stress between the ceramic layer and the metallic layer at high temperature and higher amount of tetragonal phase.

  3. Fluctuations at Electrode-YSZ Interfaces

    DEFF Research Database (Denmark)

    Jacobsen, Torben; Hansen, Karin Vels; Skou, Eivind

    of the damping by the large interface. Fig.\\,1 shows a slow potential sweep on a Pt point electrode on a YSZ surface. For the part of the anodic and the cathodic branches where the electrode approaches equilibrium, quadratic expressions are used as smooth approximations for the current -- overvoltage relation...... in D/A converters, duty cycles of thermo regulators, etc. But even so, the dramatic spikes seen at the Ni anode emphasizes the care that must be taken in order to obtain reproducible results from point electrode studies. However, it is noted that Pt cathodes and Ni anodes show reverse patterns...... property of the interface. \

  4. Magnetron-Sputtered YSZ and CGO Electrolytes for SOFC

    Science.gov (United States)

    Solovyev, A. A.; Shipilova, A. V.; Ionov, I. V.; Kovalchuk, A. N.; Rabotkin, S. V.; Oskirko, V. O.

    2016-08-01

    Reactive magnetron sputtering has been used for deposition of yttria-stabilized ZrO2 (YSZ) and gadolinium-doped CeO2 (CGO) layers on NiO-YSZ commercial anodes for solid oxide fuel cells. To increase the deposition rate and improve the quality of the sputtered thin oxide films, asymmetric bipolar pulse magnetron sputtering was applied. Three types of anode-supported cells, with single-layer YSZ or CGO and YSZ/CGO bilayer electrolyte, were prepared and investigated. Optimal thickness of oxide layers was determined experimentally. Based on the electrochemical characteristics of the cells, it is shown that, at lower operating temperatures of 650°C to 700°C, the cells with single-layer CGO electrolyte are most effective. The power density of these fuel cells exceeds that of the cell based on YSZ single-layer electrolyte at the same temperature. Power densities of 650 mW cm-2 and 500 mW cm-2 at 700°C were demonstrated by cells with single-layer YSZ and CGO electrolyte, respectively. Significantly enhanced maximum power density was achieved in a bilayer-electrolyte single cell, as compared with cells with a single electrolyte layer. Maximum power density of 1.25 W cm-2 at 800°C and 1 W cm-2 at 750°C under voltage of 0.7 V were achieved for the YSZ/CGO bilayer electrolyte cell with YSZ and CGO thickness of about 4 μm and 1.5 μm, respectively. This signifies that the YSZ thin film serves as a blocking layer to prevent electrical current leakage in the CGO layer, leading to the overall enhanced performance. This performance is comparable to the state of the art for cells based on YSZ/CGO bilayer electrolyte.

  5. Preparation of NiO-YSZ/YSZ bi-layers for solid oxide fuel cells by electrophoretic deposition

    Science.gov (United States)

    Besra, Laxmidhar; Zha, Shaowu; Liu, Meilin

    A simple and cost-effective method, starting with electrophoretic deposition (EPD) on a carbon sheet, has been developed for preparation of a NiO-YSZ anode and thin, gas-tight YSZ electrolyte layer on it for use in solid oxide fuel cells (SOFCs). The innovative feature of this approach enables the deposition of anode materials as well as the YSZ electrolyte, which were subsequently co-fired in air at high temperatures to remove the carbon and form an anode-supported dense YSZ electrolyte. A functional SOFC constructed by brush painting a layer of mixed cathode consisting of La 0.8Sr 0.2MnO 3 (LSM) and YSZ on the electrolyte layer followed by firing at 1250 °C, displayed a peak power density of 434 mW cm -2 at 800 °C when tested with H 2 as fuel and ambient air as oxidant.

  6. Long-Term Stability of LSM-YSZ Based Cathodes

    DEFF Research Database (Denmark)

    Baqué, Laura; Jørgensen, Peter Stanley; Hansen, Karin Vels

    2013-01-01

    A transmission line based model was successfully applied to study the ageing effect in LSM-YSZ cathodes after being exposed to humidified air at 900 °C for up to 3000 h. A decrease in the YSZ conductivity was correlated with the formation of the less conducting monoclinic zirconia. The amount of La......2Zr2O7, present in the non-aged samples, decreases with ageing time increasing the number of active sites for charge transfer between LSM and YSZ as well as the LSM conductivity values....

  7. Effect of porous YSZ scaffold microstructure on the long-term performance of infiltrated Ni-YSZ anodes

    Science.gov (United States)

    Buyukaksoy, Aligul; Kammampata, Sanoop P.; Birss, Viola I.

    2015-08-01

    Ni infiltration into porous YSZ scaffolds is a promising route for the construction of high performing and redox-stable Ni-YSZ anodes for application in solid oxide fuel cells (SOFCs). However, the long-term instability of this type of anode is a critical problem. Here, it is shown that an interconnected Ni film, rather than discrete Ni particles, can be formed inside a porous, pre-sintered YSZ scaffold by using a polymeric Ni-based precursor as the infiltration medium. To understand the effect of the YSZ microstructure on the long-term stability and the electrochemical performance of the resulting composites, two types of Ni-YSZ anodes were investigated. Anodes prepared by polymeric Ni infiltration into a YSZ scaffold with large grains (0.5 μm) and pores (0.5 μm and 5 μm) showed extensive agglomeration in the Ni phase, resulting in poor stability and poor activity. In contrast, Ni infiltration into YSZ scaffolds with finer particle and pore sizes (∼200 nm each) produced anodes with a very small polarization resistance of ca. 0.1 Ω cm2 per electrode at 800 °C. An increase of only ∼5% was seen in the resistance after ca. 110 h at this temperature, achieved by preventing Ni agglomeration.

  8. Need for In Operando Characterization of Electrochemical Interface Features

    DEFF Research Database (Denmark)

    Traulsen, Marie Lund; Chatzichristodoulou, Christodoulos; Hansen, Karin Vels;

    2015-01-01

    The problems of understanding the electrode reaction kinetics and in particular the degradation of the kinetics destroying the electrode performance, is briefly described. This is followed by an analysis of information that is needed and which knowledge may be acquired by available in operando...

  9. Platinum Migration at the Pt/YSZ Interface

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Jacobsen, Torben

    2006-01-01

    by potential sweep, step and impedance techniques. As expected, inductive behaviour and activation during step polarization is confirmed, but furthermore, a very accentuated noise pattern is seen during cathodic step polarization. Investigation of the YSZ and Pt surfaces afterwards reveals the growth......Electrode activation, inductive hysteresis and non-linearity are well known phenomena on Pt-YSZ electrodes, and recently also regular fluctuation patterns have been reported. The oxygen electrode on YSZ surfaces is studied at Pt micro-electrodes prepared by electrochemical etching of platinum wire...... of dendrite like Pt structures from the TPB. The formation of these may explain the observed noise and contribute to the explanation of the activation mechanism taking place at the platinum-YSZ interface....

  10. Synthesis and characterization of YSZ by spray pyrolysis technique

    Energy Technology Data Exchange (ETDEWEB)

    Jadhav, L.D., E-mail: ldjadhav.phy@gmail.com [Department of Physics, Rajaram College, Kolhapur 416 004 (India); Jamale, A.P. [Department of Physics, Shivaji University, Kolhapur 416 004 (India); Bharadwaj, S.R.; Varma, Salil [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Bhosale, C.H. [Department of Physics, Shivaji University, Kolhapur 416 004 (India)

    2012-10-01

    Highlights: Black-Right-Pointing-Pointer The YSZ thin film has been successfully deposited at 400 Degree-Sign C. Black-Right-Pointing-Pointer Deposition at 400 Degree-Sign C significantly limits the growth mechanism along (1 0 1). Black-Right-Pointing-Pointer The enhancement in conductivity exhibits the YSZ as a thin solid electrolyte. - Abstract: The conventional zirconium based yttria stabilized zirconia (YSZ) electrolyte has been synthesized from aqueous solution by cost effective air atomized spray pyrolysis technique (SPT). The films show well developed dense, nanocrystalline material. The thermal analysis of zirconyl nitrate reveals the possibility of crystalline YSZ film formation only above 400 Degree-Sign C, which is confirmed from the XRD pattern. The activation energy of 1.14 eV clarifies its conductivity behavior, verified from DC and AC conductivity measurements.

  11. Study of the Ni-NiAl{sub 2}O{sub 4}-YSZ cermet for its possible application as an anode in solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Reyes-Rojas, A [Centro de Investigacion en Materiales Avanzados SC, Miguel de Cervantes 120, Complejo Industrial Chihuahua, Chihuahua (Mexico); Universidad Autonoma del Estado de Mexico, Facultad de Quimica, Toluca (Mexico); Esparza-Ponce, H E [Centro de Investigacion en Materiales Avanzados SC, Miguel de Cervantes 120, Complejo Industrial Chihuahua, Chihuahua (Mexico); Reyes-Gasga, J [Universidad Nacional Autonoma de Mexico, Instituto de Fisica, Mexico DF (Mexico)

    2006-05-17

    Nanocrystalline Ni-NiAl{sub 2}O{sub 4}-YSZ cermet with a possible application as anode in solid oxide fuel cells (SOFCs) has been developed. The powders were prepared by using an alternative solid-state method that includes the use of nickel acetylacetonate as an inorganic precursor to obtain a highly porous material after sintering at 1400 {sup o}C and oxide reduction (NiO -Al{sub 2}O{sub 3}-YSZ {yields} Ni-NiAl{sub 2}O{sub 4}-YSZ) at 800 {sup o}C for 8 h in a tubular reactor furnace using 10% H{sub 2}/N{sub 2}. Eight samples with 45% Ni and 55% Al{sub 2}O{sub 3}-YSZ in concentrations of Al{sub 2}O{sub 3} oxides from 10 to 80 wt% of were mixed to obtain the cermets. The obtained material was compressed using unidirectional axial pressing and calcinations from room temperature to 800 {sup o}C. Good results were registered using a heating rate of 1 {sup o}C min{sup -1} and a special ramp to avoid anode cracking. Thermal expansion, electrical conductivity, and structural characterization by thermo-mechanical analyser (TMA) techniques/methods, the four-point probe method for conductivity, scanning electron microscopy (SEM), x-ray energy dispersive spectroscopy (EDS), x-ray diffraction (XRD), and the Rietveld method were carried out. Cermets in the range 5.5 to 11% Al{sub 2}O{sub 3} present a crystal size around 200 nm. An inversion degree (I) in the NiAl{sub 2}O{sub 4} spinel structure of the cermets Ni-NiAl{sub 2}O{sub 4}-YSZ was found after the sintering and reduction processes. Good electrical conductivity and thermal expansion coefficient were obtained for the cermet with 12 wt% of spinel structure formation.

  12. Fe-doped 8YSZ at different composition for solid electrolyte in solid oxide fuel cell

    Directory of Open Access Journals (Sweden)

    Johar B.

    2016-01-01

    Full Text Available Pure 8 mol% yttria stabilized zirconia (YSZ and Fe-doped (1 mol%, 2 mol% and 3 mol% YSZ electrolyte were prepared and sintered at 1550°C. Transition metal oxide is added into YSZ as sintering aided has a function to reduce the sintering temperature. The microstructure, crystal structure and ionic conductivity of pure YSZ and Fe-doped YSZ at different composition were investigated. The amount of cubic phase decreased as the amount of Fe increased. Fe-doped 8YSZ had higher conductivity than pure 8YSZ. The ionic conductivity of 3FeYSZ is 9.35×10−8 S/cm higher than 1FeYSZ which is 4.72×10−9 S/cm when operated at 300°C.

  13. Need for In Operando Characterization of Electrochemical Interface Features

    DEFF Research Database (Denmark)

    Traulsen, Marie Lund; Chatzichristodoulou, Christodoulos; Hansen, Karin Vels;

    2015-01-01

    during the recent 2 decades. This progress has to a large extent been based on combination of electrochemical characterization and in situ and in operando and in situ surface analysis techniques, which so far have been less developed for high temperature electrochemistry above 300 °C. In spite...... such as electrochemical impedance spectroscopy with in operando scanning probe microscopy and surface sensitive chemical analysis methods. Examples of results will be presented.......It has proven particularly difficult to determine the electrode reaction mechanisms in high temperature solid oxide cells (SOCs) that convert gases. The literature is full of contradictory statements and apparently contradictory findings. Often the same type of electrochemical kinetics that apply...

  14. Evidence of yttrium silicate inclusions in YSZ-porcelain veneers.

    Science.gov (United States)

    Stoner, Brian R; Griggs, Jason A; Neidigh, John; Piascik, Jeffrey R

    2014-04-01

    This report introduces the discovery of crystalline defects that can form in the porcelain veneering layer when in contact with yttria-stabilized zirconia (YSZ). The focus was on dental prostheses and understanding the defects that form in the YSZ/porcelain system; however the data reported herein may have broader implications toward the use and stability of YSZ-based ceramics in general. Specimens were cut from fully sintered YSZ plates and veneering porcelain was applied (porcelain veneer. Local EDAX (SEM) was performed in the regions of visible inclusions and showed significant increases in yttrium concentration. TEM specimens also showed apparent inclusions in the porcelain and selected area electron diffraction was performed on these regions and found the inclusions to be crystalline and identified as either yttrium-silicate (Y2 SiO5 ) or yttrium-disilicate (Y2 Si2 O7 ). Micro-CT data showed that yttrium-silicate precipitates were distributed throughout the thickness of the porcelain veneer. Future studies are needed to determine whether many of the premature failures associated with this materials system may be the result of crystalline flaws that form as a result of high temperature yttrium diffusion near the surfaces of YSZ.

  15. Preparation of NiO-YSZ/YSZ bi-layers for solid oxide fuel cells by electrophoretic deposition

    Energy Technology Data Exchange (ETDEWEB)

    Besra, Laxmidhar; Zha, Shaowu; Liu, Meilin [School of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Drive, Atlanta, GA 30332-0245 (United States)

    2006-09-29

    A simple and cost-effective method, starting with electrophoretic deposition (EPD) on a carbon sheet, has been developed for preparation of a NiO-YSZ anode and thin, gas-tight YSZ electrolyte layer on it for use in solid oxide fuel cells (SOFCs). The innovative feature of this approach enables the deposition of anode materials as well as the YSZ electrolyte, which were subsequently co-fired in air at high temperatures to remove the carbon and form an anode-supported dense YSZ electrolyte. A functional SOFC constructed by brush painting a layer of mixed cathode consisting of La{sub 0.8}Sr{sub 0.2}MnO{sub 3} (LSM) and YSZ on the electrolyte layer followed by firing at 1250{sup o}C, displayed a peak power density of 434mWcm{sup -2} at 800{sup o}C when tested with H{sub 2} as fuel and ambient air as oxidant. (author)

  16. Synthesis of Octahedral-Shaped NiO and Approaches to an Anode Material of Manufactured Solid Oxide Fuel Cells Using the Decalcomania Method

    Directory of Open Access Journals (Sweden)

    Haeran Cho

    2013-01-01

    Full Text Available Micrometer-sized and octahedral-shaped NiO particles were synthesized by microwave thermal treatment at 300 watt power for 15 min in a microwave chamber to be used as an anode material in solid oxide fuel cells. SEM image and particle size distribution revealed near-perfect octahedral NiO microparticle with sizes ranging from 4.0~11.0 μm. The anode functional layer (AFL, 60 wt% NiO synthesized: commercial 40 wt% YSZ, electrolyte (commercial Yttria-stabilized zirconia, YSZ, and cathode (commercial La0.8Sr0.2MnO3, LSM layers were manufactured using the decalcomania method on a porous anode support, sequentially. The sintered electrolyte at 1450°C for 2 h using the decalcomania method was dense and had a thickness of about 10 μm. The cathode was sintered at 1250°C for 2 h, and it was porous. Using humidified hydrogen as a fuel, a coin cell with a 15 μm thick anode functional layer exhibited maximum power densities of 0.28, 0.38, and 0.65 W/cm2 at 700, 750, and 800°C, respectively. Otherwise, when a commercial YSZ anode functional layer was used, the maximum power density was 0.55 W/cm2 at 800°C.

  17. Accelerated creep of Ni-YSZ anodes during reduction

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund; Greco, Fabio; Ni, De Wei

    2014-01-01

    by the thermomechanical history of the stack (e.g. sintering temperature, time at temperature etc.). During operation the stress state will depend on time as stresses are relaxed by creep processes. Creep has mainly been studied at operating conditions, where the Ni-YSZ anode is in the reduced state and YSZ is the main...... load-carrying component. In this work we report on a new creep-reduction phenomenon observed to take place during the reduction process itself, where stresses are relaxed at a rate much faster (~×104) than during operation where the anode is in fully reduced state. Furthermore, samples exposed...... to a very small tensile stress (0.004 MPa) were observed to expand during reduction, which is in contrast with reports in literature [Ref].The “accelerated” creep has a tremendous impact on the stress field in an operating SOFC stack. Creep experiments, where carried out on NiO-YSZ anode support structures...

  18. Dynamic transformation of small Ni particles during methanation of CO2 under fluctuating reaction conditions monitored by operando X-ray absorption spectroscopy

    Science.gov (United States)

    Mutz, B.; Carvalho, H. W. P.; Kleist, W.; Grunwaldt, J.-D.

    2016-05-01

    A 10 wt.-% Ni/Al2O3 catalyst with Ni particles of about 4 nm was prepared and applied in the methanation of CO2 under dynamic reaction conditions. Fast phase transformations between metallic Ni, NiO and NiCO3 were observed under changing reaction atmospheres using operando X-ray absorption spectroscopy (XAS). Removing H2 from the feed gas and, thus, simulating a H2 dropout during the methanation reaction led to oxidation of the active sites. The initial reduced state of the Ni particles could not be recovered under methanation atmosphere (H2/CO2 = 4); this was only possible with an effective reactivation step applying H2 at increased temperatures. Furthermore, the cycling of the gas atmospheres resulted in a steady deactivation of the catalyst. Operando XAS is a powerful tool to monitor these changes and the behavior of the catalyst under working conditions to improve the understanding of the catalytic processes and deactivation phenomena.

  19. Kinetic Studies on Ni-YSZ Composite Electrodes

    DEFF Research Database (Denmark)

    Njodzefon, Jean-Claude; Sudireddy, Bhaskar Reddy; Hjelm, Johan;

    2015-01-01

    AC and DC techniques were applied to investigate the electrochemical reaction kinetics of porous composite Ni/8-mol% yttria-stabilized zirconia (Ni/8YSZ) solid oxide cell (SOC) electrodes using a novel pseudo-3-electrode cell geometry. From OCV impedance spectra an activation energy Ea of 1.13 eV...

  20. Thermal memory effects at the Pt vertical bar YSZ interface

    DEFF Research Database (Denmark)

    Jacobsen, Torben; Bay, Lasse

    2002-01-01

    A current induced activation mechanism in the oxygen reaction on the Pt \\ YSZ interface at 1000 degreesC is demonstrated by impedance measurements. It is shown that Pt point electrodes conditioned at high temperature retain their initial reactivity when cooled to 600 degreesC. At this temperature...

  1. Effects of NiO addition on the densification, microstructure and electrical conductivity of Yttria fully-stabilized zirconia; Efeitos da adicao do NiO na densificacao, na microestrutura e na condutividade eletrica da zirconia totalmente estabilizada com itria

    Energy Technology Data Exchange (ETDEWEB)

    Batista, Rafael Morgado

    2010-07-01

    The effects produced by NiO addition to yttria fully-stabilized zirconia were systematically investigated. Commercial zirconia-8 mol% yttria, nickel acetate, nitrate, trihydroxycarbonate and nickel oxide were used as starting materials. The NiO content varied from 0.5 to 5 mol%, and the compositions were prepared by mechanically mixing the starting materials in the stoichiometric proportions. Densification studies carried out by density and dilatometry measurements revealed that the maximum shrinkage ({approx}16-{approx}20%) depends on the type of nickel precursor. In the second sintering stage the linear shrinkage increased with increasing NiO content (precursor: nickel trihydroxy-carbonate). In the first sintering stage, the activation energy for grain boundary diffusion changed according to the additive precursor, being lower for the oxide and higher for the trihydroxy-carbonate. In the second stage, when the major part of porosity is eliminated, the maximum shrinkage rate temperatures were found to be independent on the precursor except when nickel acetate is used. The solubility limit at 1350 degree C is 1.48% as determined by X-ray diffraction. Above the solubility limit the excess NiO is retained as a second randomly distributed phase. The main effect of the additive in the ceramic microstructure is to increase the average grain size. The electrical measurements showed that the additive did not produce any significant effect in the grain conductivity irrespective of the sintering time, except when the precursor material was nickel oxide. In this case, the grain conductivity increased with increasing sintering time. This effect is attributed to the crystallite size of the nickel oxide precursor, which is higher than that of 8YSZ, slowing down the formation of solid solution. However, the grain conductivity of samples prepared with nickel trihydroxy-carbonate precursor is slightly lower than those of other samples. The samples sintered for 15 h exhibited an

  2. Operando Raman Micro Spectroscopy of Polymer Electrolyte Fuel Cells

    Science.gov (United States)

    2016-01-16

    H3152 Journal of The Electrochemical Society, 163 (4) H3152-H3159 (2016) JES FOCUS ISSUE HONORING ALLEN J. BARD Operando Raman Micro- Spectroscopy of...Chemistry, 79(6), 2367 (2007). 30. H. W. Abernathy et al., “Monitoring Ag-Cr interactions in SOFC cathodes using Raman spectroscopy ,” Journal of Physical...obtain reliable inner water contents,” Journal of Raman Spectroscopy , 44(2), 321 (2013). 32. P. Huguet et al., “In situ analysis of water management

  3. Neurônios espelho

    Directory of Open Access Journals (Sweden)

    Allan Pablo Lameira

    2006-01-01

    Full Text Available Os neurônios espelho foram descritos inicialmente em macaco Rhesus. Estes neurônios disparavam quando o macaco realizava ações específicas (como pegar uvas passa ou quando ele observava a mesma ação realizada por outro macaco ou por um pesquisador. Assim, estes neurônios possibilitam a compreensão da ação e/ou da intenção de outro animal pela ativação subliminar desta ação nos circuitos fronto-parietais. Estes neurônios estariam envolvidos com a origem da linguagem humana e a sua disfunção poderia causar autismo. Nesta revisão, descrevemos, em humanos e em primatas não-humanos, as áreas corticais com atividade tipo “neurônio espelho” e as áreas envolvidas com o planejamento e a execução explícita e implícita de ações. Existe uma grande sobreposição entre estas áreas, bem como com as áreas envolvidas com o reconhecimento da lateralidade de partes do corpo. Sugerimos então que os neurônios espelho também podem estar envolvidos com o reconhecimento da lateralidade de partes do corpo.

  4. Effects of co-sintering in self-standing CGO/YSZ and CGO/ ScYSZ dense bi-layers

    DEFF Research Database (Denmark)

    Teocoli, Francesca; Ni, De Wei; Brodersen, Karen;

    2014-01-01

    -standing bi-layered electrolyte system. The combined use of thermo-mechanical analysis, optical dilatometry, and scanning electron microscopy ensures a systematic characterization of both the individual layers and CGO/YSZ and CGO/ScYSZ bi-layered laminates. The results of the co-firing process of the bi...

  5. Ni-YSZ Substrate Degradation during Carbon Deposition

    Directory of Open Access Journals (Sweden)

    Marinšek, Marjan

    2011-06-01

    Full Text Available Carbon deposition on various Ni-YSZ catalytic composites with average Ni particle size from 0.44 mm to 0.98 μm was studied under dry CH4-Ar and humidified CH4-Ar conditions. The change in the catalytic activity was monitored both as a mass gain due to carbon deposition and hydrogen evolution due to CH4 dehydrogenation on Ni-YSZ. Regarding the start of methane decomposition and subsequent catalyst deactivation rate, composites with smaller Ni-grains were much more active in comparison to those with relatively large grains. Dry methane conditions always caused coking of the catalyst substrate with substantial activity loss. In contrast, under humidified methane atmosphere conditions with a steam to carbon (S/C ratio of 0.82, catalytic activity of the Ni-YSZ composites remained nearly undiminished after 2,000 minutes at chosen deposition temperatures (600–800 °C. On the catalyst surface, some encapsulation of Ni with the deposited carbon was noticed while carbon filaments grew inside the treated samples. The dimensions of C-filaments were influenced by treatment conditions and Ni-YSZ substrate morphology.

    La deposición de carbón en diferentes compuestos catalizadores Ni-YSZ con un tamaño promedio de partícula Ni de 0.44 mm a 0.98 μm fue estudiado bajo condiciones secas: CH4-Ar y húmedas: CH4-Ar. El cambio de la actividad catalítica fue monitoreado tanto como una ganancia de masa debida a la deposición de carbón y una evolución de hidrógeno debido a la deshidrogenación de CH4 en Ni-YSZ. En cuanto al comienzo de descomposición del metano y a la subsiguiente desactivación del catalizador, aquellos compuestos con granos Ni menores fueron mucho más activos en comparación a aquellos con granos relativamente mayores. Las condiciones secas del metano siempre causaron coquificación del sustrato del catalizador con una sustancial pérdida de actividad. Por el

  6. LSM-YSZ Cathodes with Reaction-Infiltrated Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Chun; Sholklapper, Tal Z.; Jacobson, Craig P.; Visco, StevenJ.; De Jonghe, Lutgard C.

    2006-01-31

    To improve the LSM-YSZ cathode performance of intermediate temperature solid oxide fuel cells (SOFCs), Sm0.6Sr0.4CoO3-sigma (SSC) perovskite nanoparticles are incorporated into the cathodes by a reaction-infiltration process. The SSC particles are {approx}20 to 80nm in diameter, and intimately adhere to the pore walls of the preformed LSM-YSZ cathodes. The SSC particles dramatically enhance single-cell performance with a 97 percent H2+3 percent H2O fuel, between 600 C and 800 C. Consideration of a simplified TPB (triple phase boundary) reaction geometry indicates that the enhancement may be attributed to the high electrocatalytic activity of SSC for electrochemical reduction of oxygen in a region that can be located a small distance away from the strict triple phase boundaries. The implication of this work for developing high-performance electrodes is also discussed.

  7. Growth and characterization of barium oxide nanoclusters on YSZ(111)

    Energy Technology Data Exchange (ETDEWEB)

    Nachimuthu, Ponnusamy; Kim, Yong Joo; Kuchibhatla, Satyanarayana V N T; Yu, Zhongqing; Jiang, Weilin; Engelhard, Mark H.; Shutthanandan, V.; Szanyi, Janos; Thevuthasan, Suntharampillai

    2009-08-13

    Barium oxide (BaO) was grown on YSZ(111) substrate by oxygen-plasma-assisted molecular beam epitaxy (OPA-MBE). In-situ reflection high-energy electron diffraction, ex-situ x-ray diffraction, atomic force microscopy and x-ray photoelectron spectroscopy have confirmed that the BaO grows as clusters on YSZ(111). During and following the growth under UHV conditions, BaO remains in single phase. When exposed to ambient conditions, the clusters transformed to BaCO3 and/or Ba(OH)2 H2O. However, in a few attempts of BaO growth, XRD results show a fairly single phase cubic BaO with a lattice constant of 0.5418(1) nm. XPS results show that exposing BaO clusters to ambient conditions results in the formation BaCO3 on the surface and partly Ba(OH)2 throughout in the bulk. Based on the observations, it is concluded that the BaO nanoclusters grown on YSZ(111) are highly reactive in ambient conditions. The variation in the reactivity of BaO between different attempts of the growth is attributed to the cluster size.

  8. Microstructural properties of multi-nano-layered YSZ thin films

    Energy Technology Data Exchange (ETDEWEB)

    Amezaga-Madrid, P.; Antunez-Flores, W.; Gonzalez-Hernandez, J.; Saenz-Hernandez, J.; Campos-Venegas, K.; Solis-Canto, O.; Ornelas-Gutierrez, C.; Vega-Becerra, O.; Martinez-Sanchez, R. [Centro de Investigacion en Materiales Avanzados S.C., Miguel de Cervantes 120, Chihuahua, Chih, CP. 31109 (Mexico); Miki-Yoshida, M., E-mail: mario.miki@cimav.edu.m [Centro de Investigacion en Materiales Avanzados S.C., Miguel de Cervantes 120, Chihuahua, Chih, CP. 31109 (Mexico)

    2010-04-16

    We report the fabrication of submicron, multi-nano-layered, yttria-stabilized zirconia (YSZ) thin films by aerosol assisted CVD. The film consisted of a periodic stack of several layers, a few nanometers thick, of the same composition but different density; formation of voids during synthesis originate the low-density layer. Grazing incidence X-ray diffraction (GIXRD), X-ray reflectometry, high-resolution transmission electron microscopy (HRTEM) and high angle annular dark field (HAADF) images were employed to analyze the microstructure of the films. GIXRD pattern showed characteristic peaks of cubic zirconia. Peak broadening in the pattern comes from a microstructure composed of nanocrystals, but principally due to the multilayered structure, that cause satellite peaks around the Bragg reflections. Lattice fringes measurement in HRTEM and HAADF images was consistent with the interplanar distance of the YSZ cubic phase. Additionally, lattice parameter obtained from selected area electron diffraction and GIXRD patterns was around 0.513 nm, in agreement to values reported in the literature for YSZ.

  9. PEALD YSZ-based bilayer electrolyte for thin film-solid oxide fuel cells

    Science.gov (United States)

    Yu, Wonjong; Cho, Gu Young; Hong, Soonwook; Lee, Yeageun; Kim, Young Beom; An, Jihwan; Cha, Suk Won

    2016-10-01

    Yttria-stabilized zirconia (YSZ) thin film electrolyte deposited by plasma enhanced atomic layer deposition (PEALD) was investigated. PEALD YSZ-based bi-layered thin film electrolyte was employed for thin film solid oxide fuel cells on nanoporous anodic aluminum oxide substrates, whose electrochemical performance was compared to the cell with sputtered YSZ-based electrolyte. The cell with PEALD YSZ electrolyte showed higher open circuit voltage (OCV) of 1.0 V and peak power density of 182 mW cm-2 at 450 °C compared to the one with sputtered YSZ electrolyte(0.88 V(OCV), 70 mW cm-2(peak power density)). High OCV and high power density of the cell with PEALD YSZ-based electrolyte is due to the reduction in ohmic and activation losses as well as the gas and electrical current tightness.

  10. Functional materials analysis using in situ and in operando X-ray and neutron scattering.

    Science.gov (United States)

    Peterson, Vanessa K; Papadakis, Christine M

    2015-03-01

    In situ and in operando studies are commonplace and necessary in functional materials research. This review highlights recent developments in the analysis of functional materials using state-of-the-art in situ and in operando X-ray and neutron scattering and analysis. Examples are given covering a number of important materials areas, alongside a description of the types of information that can be obtained and the experimental setups used to acquire them.

  11. Functional materials analysis using in situ and in operando X-ray and neutron scattering

    Directory of Open Access Journals (Sweden)

    Vanessa K. Peterson

    2015-03-01

    Full Text Available In situ and in operando studies are commonplace and necessary in functional materials research. This review highlights recent developments in the analysis of functional materials using state-of-the-art in situ and in operando X-ray and neutron scattering and analysis. Examples are given covering a number of important materials areas, alongside a description of the types of information that can be obtained and the experimental setups used to acquire them.

  12. "Património" versus património insular

    OpenAIRE

    Vale, Celina

    2011-01-01

    Este artigo pretende dar um contributo para um melhor entendimento do que é o "património insular", e eventualmente alimentar a discussão para reconsideração da orientação dada ao respectivo processo que lhe é inerente.

  13. Synthesis of YSZ@Ni Nanoparticle by Modified Electroless Plating Process.

    Science.gov (United States)

    Yu, Ping; Zheng, Haizhong; Li, Guifa; Xiong, Lingling; Luo, Qinhao

    2015-12-01

    Ni-YSZ (Y2O3-stabilized ZrO2) composites with core-shell structure (YSZ@Ni) were produced by modified electroless plating process. It was found that YSZ nanoparticles were well encapsulated by nickel powders at 65 degrees C with pH = 12. The spherical nanopowders had core-shell structure and the shell layer was less than 20 nm. The X-ray diffraction (XRD) analysis inferred the production was composed of YSZ and Ni crystals. In the end, the formation mechanism was discussed.

  14. Chromium poisoning of LSM/YSZ and LSCF/CGO composite cathodes

    DEFF Research Database (Denmark)

    Bentzen, Janet Jonna; Høgh, Jens Valdemar Thorvald; Barfod, Rasmus;

    2009-01-01

    An electrochemical study of SOFC cathode degradation, due to poisoning by chromium oxide vapours, was performed applying 3-electrode set-ups. The cathode materials comprised LSM/YSZ and LSCF/CGO composites, whereas the electrolyte material was 8YSZ. The degradation of the cathode performance...... from 300 to 2,970 h. Both LSM/YSZ and LSCF/CGO cathodes were sensitive to chromium poisoning; LSCF/CGO cathodes to a lesser extent than LSM/YSZ. Humid air aggravated the degradation of the cathode performance. Post-mortem electron microscopic investigations revealed several Cr-containing compounds...

  15. Electrophoretic deposition on non-conducting substrates: The case of YSZ film on NiO-YSZ composite substrates for solid oxide fuel cell application

    Energy Technology Data Exchange (ETDEWEB)

    Besra, Laxmidhar [Colloids and Materials Chemistry Department, Regional Research Laboratory (CSIR), Bhubaneswar 751013, Orissa (India); Compson, Charles; Liu, Meilin [School of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Drive, Atlanta, GA 30332-0245 (United States)

    2007-11-08

    This paper report the results of our investigation on electrophoretic deposition (EPD) of YSZ particles from its suspension in acetylacetone onto a non-conducting NiO-YSZ substrate. In principle, it is not possible to carry out electrophoretic deposition on non-conducting substrates. In this case, the EPD of YSZ particles on a NiO-YSZ substrate was made possible through the use of an adequately porous substrate. The continuous pores in the substrates, when saturated with the solvent, helped in establishing a ''conductive path'' between the electrode and the particles in suspension. Deposition rate was found to increase with increasing substrate porosity up to a certain value. The higher the applied voltage, the faster the deposition. For a given applied voltage, there exists a threshold porosity value below which EPD becomes practically impossible. An SOFC constructed on bi-layers of NiO-YSZ/YSZ with YSZ layer thickness of 40 {mu}m exhibited an open circuit voltage (OCV) of 0.97 V at 650 C and peak power density of 263.8 mW cm{sup -2} at 850 C when tested with H{sub 2} as fuel and ambient air as oxidant. (author)

  16. Electrophoretic deposition on non-conducting substrates: The case of YSZ film on NiO-YSZ composite substrates for solid oxide fuel cell application

    Science.gov (United States)

    Besra, Laxmidhar; Compson, Charles; Liu, Meilin

    This paper report the results of our investigation on electrophoretic deposition (EPD) of YSZ particles from its suspension in acetylacetone onto a non-conducting NiO-YSZ substrate. In principle, it is not possible to carry out electrophoretic deposition on non-conducting substrates. In this case, the EPD of YSZ particles on a NiO-YSZ substrate was made possible through the use of an adequately porous substrate. The continuous pores in the substrates, when saturated with the solvent, helped in establishing a "conductive path" between the electrode and the particles in suspension. Deposition rate was found to increase with increasing substrate porosity up to a certain value. The higher the applied voltage, the faster the deposition. For a given applied voltage, there exists a threshold porosity value below which EPD becomes practically impossible. An SOFC constructed on bi-layers of NiO-YSZ/YSZ with YSZ layer thickness of 40 μm exhibited an open circuit voltage (OCV) of 0.97 V at 650 °C and peak power density of 263.8 mW cm -2 at 850 °C when tested with H 2 as fuel and ambient air as oxidant.

  17. Development of Fe-Ni/YSZ-GDC electrocatalysts for application as SOFC anodes: XRD and TPR characterization and evaluation in the ethanol steam reforming reaction

    Energy Technology Data Exchange (ETDEWEB)

    da Paz Fiuza, Raigenis; Aurelio da Silva, Marcos; Boaventura, Jaime Soares [Energy and Materials Science Group - GECIM, Institute of Chemistry, Physical Chemistry Department, Universidade Federal da Bahia, 41170290 Salvador, Bahia (Brazil)

    2010-10-15

    Electrocatalysts based on Fe-Ni alloys were prepared by means of modified Pechini and physical mixture methods and using on a composite of Yttria Stabilized Zirconia (YSZ) and Gadolinia-Doped Ceria (GDC) as support. The former method was based on the formation a polymeric precursor that was subsequently calcined; the later method was based on the mixture of NiO and the support. The resulting composites had 35 wt.% metal load and 65 wt.% support (70 wt.% YSZ and 30 wt.% GDC mixture) (cermets). The samples were then characterized by Temperature-Programmed Reduction (TPR) and X-Ray Diffraction (XRD) and evaluated in the ethanol steam reforming at 650 C for 6 h in the temperature range of 300-900 C. The XRD results showed that the bimetallic sample calcined at 800 C formed a mixed oxide (NiFe{sub 2}O{sub 4}) with a spinel structure, which, after reduction in hydrogen, formed Ni-Fe alloys. The presence of Ni was observed to decrease the final reduction temperature of the NiFe{sub 2}O{sub 4} species. The addition of iron to the nickel anchored to YSZ-GDC increased the hydrogen production and inhibited carbon deposition. The resulting bimetallic 30Fe5Ni sample reached an ethanol conversion of about 95% and a hydrogen yield up to 48% at 750 C. In general, ethanol conversion and hydrogen production were independent of the metal content in the electrocatalyst. However, the substitution of nickel for iron significantly reduced carbon deposition on the electrocatalyst: 74, 31, and 9 wt.% in the 35Ni, 20Fe15Ni, and 30Fe5Ni samples, respectively. (author)

  18. Study of the formation of secondary phases in the composite LSM/YSZ; Estudo da formacao de fases secundarias no composito LSM/YSZ

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Ranieri Andrade

    2007-07-01

    The composite of strontium-doped lanthanum manganite (La{sub 1-x}SrxMnO{sub 3} - LSM) and Yttria-stabilized zirconia (ZrO{sub 2}/Y{sub 2}O{sub 3} - YSZ), is indicated as cathode of the Solid Oxide Fuel Cells (SOFC). It presents better acting as cathode due to the Triple Phase Boundary (TPB) formed in the interface area between the cathode and the electrolyte. For the temperatures up to 1100 deg C, LSM and YSZ can react producing lanthanum zirconate (La{sub 2}Zr{sub 2}O{sub 7} - LZO) and strontium zirconate (SrZrO{sub 3} - SZO). In this sense, the present work intends to contribute in the study of the formation of phases LZO and SZO, studying different massic proportions between LSM and YSZ with sintering temperatures varying between 1000 deg C and 1400 deg C. For the obtention of the precursory powders the co-precipitation routes were adopted to obtain YSZ and conventional powder mixture for the preparation of LSM. The composite LSM/YSZ, studied in this work, is prepared with two concentrations of Sr for LSM (30 mol por cent - LSM7 and 40 mol por cent - LSM6) and one concentration of Yttria for YSZ (10 mol por cent). The results obtained by X-ray fluorescence showed that the routes adopted for synthesis of powders were effective in the obtention of the compositions LSM6, LSM7 and YSZ, with close values to the stoichiometric. The studied massic proportions were: 50 por cent of LSM and 50 por cent of YSZ (1:1), 25 por cent of LSM and 75 por cent of YSZ (1:3), and 75 por cent of LSM and 25 por cent of YSZ (3:1). Such proportions of mixtures were conformed and submitted at different conditions of temperatures and times of sintering: 1000 deg C, 1200 deg C, 1300 deg C, 1350 deg C and 1400 deg C for 4 and 8 hours. The values of medium size of the particles and the specific surface area values for the mixture of LSM6/YSZ and LSM7/YSZ, are of the same order of largeness after the mixture in a attrition mill and in different massic proportions. Secondary phases like LZO and

  19. Dimensional behavior of Ni-YSZ composites during redox cycling

    DEFF Research Database (Denmark)

    Pihlatie, Mikko; Kaiser, Andreas; Larsen, Peter Halvor;

    2009-01-01

    The dimensional behavior of Ni-yttria-stabilized zirconia (YSZ) cermets during redox cycling was tested in dilatometry within the temperature range 600-1000 degrees C. The effect Of humidity oil redox stability was investigated at intermediate and low temperatures. We show that both the sintering...... of nickel depending on temperature of the initial reduction and the operating conditions, and the temperature of reoxidation are very important for the size of the dimensional change. Cumulative redox strain (CRS) is shown to be correlated with temperature. Measured maximum CRS after three redox cycles...

  20. Effects of Heat-treatments on the Mechanical Strength of Coated YSZ: An Experimental Assessment

    DEFF Research Database (Denmark)

    Toftegaard, Helmuth Langmaack; Sørensen, Bent F.; Linderoth, Søren;

    2009-01-01

    The mechanical strength of thin, symmetric sandwich specimens consisting of a dense yttria-stabilized zirconia (YSZ) substrate coated with a porous NiO–YSZ layer at both major faces was investigated. Specimens were loaded in uniaxial tension to failure following heat treatments at various...

  1. Ni/YSZ anode – Effect of pre-treatments on cell degradation and microstructures

    DEFF Research Database (Denmark)

    Hauch, Anne; Jørgensen, Peter Stanley; Brodersen, Karen

    2011-01-01

    Anode supported (Ni/YSZ–YSZ–LSM/YSZ) solid oxide fuel cells were tested and the degradation over hundreds of hours was monitored and analyzed by impedance spectroscopy. Test conditions were chosen to focus on the Ni/YSZ anode degradation and all tests were operated at 750°C, a current density of ...

  2. The Effect of a CGO Barrier Layer on the Performance of LSM/YSZ SOFC Cathodes

    DEFF Research Database (Denmark)

    Kammer Hansen, Kent; Menon, Mohan; Knudsen, Jesper

    2010-01-01

    by spin coating. Electrochemical impedance spectroscopy (EIS) was used to evaluate the performance of the LSM/YSZ composite electrodes. It was shown that the CGO barrier layer affects both the performance of the LSM/YSZ composite electrodes and the series resistance of the cells. This indicates...

  3. Properties of nano-structured Ni/YSZ anodes fabricated from plasma sprayable NiO/YSZ powder prepared by single step solution combustion method

    Science.gov (United States)

    Prakash, B. Shri; Balaji, N.; Kumar, S. Senthil; Aruna, S. T.

    2016-12-01

    NiO/YSZ anode coatings are fabricated by atmospheric plasma spraying at different plasma powers from plasma grade NiO/YSZ powders that are prepared in a single step by solution combustion method. The process adopted is devoid of multi-steps that are generally involved in conventional spray drying or fusing and crushing methods. Density of the coating increased and porosity decreased with increase in the plasma power of deposition. An ideal nano-structured Ni/YSZ anode encompassing nano YSZ particles, nano Ni particles and nano pores is achieved on reducing the coating deposited at lower plasma powers. The coating exhibit porosities in the range of 27%, sufficient for anode functional layers. Electronic conductivity of the coatings is in the range of 600 S/cm at 800 °C.

  4. Preparation of YSZ solid electrolyte by slip casting and its properties

    Institute of Scientific and Technical Information of China (English)

    DOU Jing; LI Heping; XU Liping; ZHANG Lei; WANG Guangwei

    2009-01-01

    Fully stabilized YSZ solid electrolyte was prepared by slip casting. The density was measured according to the Archimedes principle and the linear shrinkage was calculated from measuring the sizes of samples before and after sintering. XRD analysis was conducted to verify the phase structure of both the starting YSZ powder and the prepared YSZ electrolyte. The microstructure of fracture surface and the electrical properties of the samples sintered at different temperatures were investigated via SEM and a complex impedance method, respectively. By comparison of the properties and features among the samples, a slip casting method was established to be a simple way to manufacture high-quality YSZ electrolyte at the sintering temperature of 1550℃ for 3 h, which provides a new approach for YSZ electrolyte with com-plex shapes and mass production.

  5. Preparation and properties of highly porous, biomorphic YSZ ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Rambo, C.R.; Cao, J.; Sieber, H

    2004-10-15

    Highly porous, biomorphic YSZ (yttria-stabilized zirconia) ceramics were manufactured by infiltration of zirconium-oxychloride (ZrOCl{sub 2}{center_dot}8H{sub 2}O) sol into biological template structures derived from rattan and pine wood. 3-5 mol% yttrium nitrate (Y(NO{sub 3}){sub 3}{center_dot}5H{sub 2}O) was added to the sol to stabilize the tetragonal ZrO{sub 2} phase. After vacuum-assisted infiltration, the specimens were pyrolysed at 800 deg. C in N{sub 2} atmosphere. Repeated infiltrations and subsequent annealing in air at temperatures up to 1550 deg. C yields the burn out of the biocarbon template and resulted in the formation of biomorphous YSZ ceramics, which maintained the microstructural features of the biological preform. Depending on the type of the biological template as well as the processing parameters, biomorphic ZrO{sub 2} ceramics with an unidirected pore morphology and a large variety of microstructures can be obtained.

  6. Complex structural dynamics of nanocatalysts revealed in Operando conditions by correlated imaging and spectroscopy probes.

    Science.gov (United States)

    Li, Y; Zakharov, D; Zhao, S; Tappero, R; Jung, U; Elsen, A; Baumann, Ph; Nuzzo, R G; Stach, E A; Frenkel, A I

    2015-06-29

    Understanding how heterogeneous catalysts change size, shape and structure during chemical reactions is limited by the paucity of methods for studying catalytic ensembles in working state, that is, in operando conditions. Here by a correlated use of synchrotron X-ray absorption spectroscopy and scanning transmission electron microscopy in operando conditions, we quantitatively describe the complex structural dynamics of supported Pt catalysts exhibited during an exemplary catalytic reaction-ethylene hydrogenation. This work exploits a microfabricated catalytic reactor compatible with both probes. The results demonstrate dynamic transformations of the ensemble of Pt clusters that spans a broad size range throughout changing reaction conditions. This method is generalizable to quantitative operando studies of complex systems using a wide variety of X-ray and electron-based experimental probes.

  7. Complex structural dynamics of nanocatalysts revealed in Operando conditions by correlated imaging and spectroscopy probes

    Science.gov (United States)

    Li, Y.; Zakharov, D.; Zhao, S.; Tappero, R.; Jung, U.; Elsen, A.; Baumann, Ph.; Nuzzo, R. G.; Stach, E. A.; Frenkel, A. I.

    2015-06-01

    Understanding how heterogeneous catalysts change size, shape and structure during chemical reactions is limited by the paucity of methods for studying catalytic ensembles in working state, that is, in operando conditions. Here by a correlated use of synchrotron X-ray absorption spectroscopy and scanning transmission electron microscopy in operando conditions, we quantitatively describe the complex structural dynamics of supported Pt catalysts exhibited during an exemplary catalytic reaction--ethylene hydrogenation. This work exploits a microfabricated catalytic reactor compatible with both probes. The results demonstrate dynamic transformations of the ensemble of Pt clusters that spans a broad size range throughout changing reaction conditions. This method is generalizable to quantitative operando studies of complex systems using a wide variety of X-ray and electron-based experimental probes.

  8. Preparation of YSZ film by EPD and its application in SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Jia Li [Center for Condensed Matter Science and Technology, Harbin Institute of Technology, Harbin 150001 (China); Department of Physics, Dalian University of Technology, Dalian 116024 (China); Lue Zhe [Center for Condensed Matter Science and Technology, Harbin Institute of Technology, Harbin 150001 (China); Huang Xiqiang [Center for Condensed Matter Science and Technology, Harbin Institute of Technology, Harbin 150001 (China); Liu Zhiguo [Center for Condensed Matter Science and Technology, Harbin Institute of Technology, Harbin 150001 (China); Chen Kongfa [Center for Condensed Matter Science and Technology, Harbin Institute of Technology, Harbin 150001 (China); Sha Xueqing [Center for Condensed Matter Science and Technology, Harbin Institute of Technology, Harbin 150001 (China); Li Guoqing [Department of Physics, Dalian University of Technology, Dalian 116024 (China); Su Wenhui [Center for Condensed Matter Science and Technology, Harbin Institute of Technology, Harbin 150001 (China) and Department of Physics, Dalian University of Technology, Dalian 116024 (China) and Department of Condensed Matter Physics, Jilin University, Changchun 130023 (China) and International Center for Materials Physics, Academia Sinica, Shenyang 110015 (China)]. E-mail: suwenhui@hit.edu.cn

    2006-11-09

    An electrophoretic deposition (EPD) method was applied for the preparation of yttria-stabilized zirconia (YSZ) thin film on a NiO-YSZ porous anode substrate for solid oxide fuel cell (SOFC) applications. Dense YSZ film with uniform thickness can be readily prepared with the EPD method using isopropanol as solvent and iodine as dispersant. As EPD electrode, the NiO-YSZ substrate was covered with a graphite layer to obtain enough electric conductivity. A series of experiments, such as suspension concentration, sintering shrinkage, and so on, were conducted in order to optimize the EPD technique. A planar-type SOFC was fabricated using La{sub 0.4}Sr{sub 0.6}Co{sub 0.2}Fe{sub 0.8}O{sub 3} (LSCF) as the cathode and YSZ film deposited onto the NiO-YSZ anode substrate as the electrolyte. The fuel cell exhibited an open circuit voltage of about 1.0 V and a maximum power density of 440 mW/cm{sup 2} at 900 deg. C. Thus, the EPD method was a suitable technology for the formation of gas-tight YSZ film.

  9. Effect of sintering temperature on the microstructure, roughness and electrochemical impedance of electrophoretically deposited YSZ electrolyte for SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Talebi, Tahereh; Haji, Mohsen; Raissi, Babak [Materials and Energy Research Center, P. Box 14155-4777, Karaj, Tehran (Iran)

    2010-09-15

    In the present work, the microstructures of YSZ electrolyte films, which were sintered at various temperatures in the range of 1300-1600 C, were investigated. First, a suitable and uniform film was deposited on the surface of NiO-YSZ composite by EPD. After the consequence sintering, the surfaces of deposited YSZ films were observed by SEM. In addition, other characteristics of the YSZ electrolyte films such as surface roughness and morphology of the sintered films were investigated by AFM. The ability of ionic transfer and permeability of the YSZ electrolyte was examined by electrochemical impedance spectroscopy at different temperatures. It seems that the YSZ electrolyte sintered at 1400 C was appropriate for SOFCs applications, because this film had the minimum impedance, minimum roughness and the maximum conductivity. Furthermore, the temperature of 1400 C was the minimum temperature in which a dense film of YSZ was formed uniformly on the surface of anode and coated it completely. (author)

  10. Investigation of the degradation of LSM-YSZ SOFC cathode by electrochemical impedance spectroscopy

    DEFF Research Database (Denmark)

    Torres da Silva, Iris Maura

    conductivity would not be a problem during degradation experiments of the cells. The experiments carried out for this purpose include x-ray diffraction, conductivity and dilatometry. LSM-YSZ/YSZ/LSM-YSZ symmetrical cells were prepared and investigated by means ofelectrochemical impedance spectroscopy...... that at the applied operating conditions the impedance data could not be deconvoluted as anode and cathode processes were overlapping. Nonetheless it appeared that at OCV the degradation of the cathode is similar for symmetrical and single cells. Under current degradation was significantly lower, so real performance...

  11. First principles exploration of NiO and its ions NiO+ and NiO-.

    Science.gov (United States)

    Sakellaris, Constantine N; Mavridis, Aristides

    2013-02-07

    We present a high level ab initio study of NiO and its ions, NiO(+) and NiO(-). Employing variational multireference configuration interaction (MRCI) and single reference coupled-cluster methods combined with basis sets of quintuple quality, 54, 20, and 10 bound states of NiO, NiO(+), and NiO(-) have been studied. For all these states, complete potential energy curves have been constructed at the MRCI level of theory; in addition, for the ground states of the three species core subvalence (3s(2)3p(6)∕(Ni)) and scalar relativistic effects have been taken into account. We report energetics, spectroscopic parameters, dipole moments, and spin-orbit coupling constants. The agreement with experiment is in the case of NiO good, but certain discrepancies that need further investigation have arisen in the case of the anion whose ground state remains computationally a tantalizing matter. The cation is experimentally almost entirely unexplored, therefore, the study of many states shall prove valuable to further investigators. The ground state symmetry, bond distances, and binding energies of NiO and NiO(+) are (existing experimental values in parenthesis), X(3)Σ(-)(X(3)Σ(-)), r(e) = 1.606 (1.62712) Å, D(0) = 88.5 (89.2 ± 0.7) kcal/mol, and X(4)Σ(-)(?), r(e) = 1.60(?) Å, D(0) = 55 (62.4 ± 2.4) kcal/mol, respectively. The ground state of NiO(-) is (4)Σ(-) (but (2)Π experimentally) with D(0) = 85-87 (89.2 ± 0.7) kcal/mol.

  12. Fabricating Pinhole-Free YSZ Sub-Microthin Films by Magnetron Sputtering for Micro-SOFCs

    Directory of Open Access Journals (Sweden)

    T. Hill

    2011-01-01

    Full Text Available Submicron thin yttria stabilized zirconia (YSZ films were prepared on a variety of substrates with different surface morphologies by magnetron sputtering followed by thermal oxidation. Pinholes were observed in the films deposited on nanoporous alumina substrates. Initial dense Y/Zr films developed nanocracks after thermal oxidation on smooth Si wafer substrates. At optimal sputtering and oxidation conditions, smooth and crack/pore-free films were achieved on Si wafer substrates. The thin YSZ films exhibited fully ionic conduction with ionic conductivities, and activation energy corroborated well with the values from commercial YSZ plates. The thin YSZ films can be utilized in Solid Oxide Fuel Cells (SOFCs for intermediate temperature operations.

  13. Impedance Analysis of 7YSZ Thermal Barrier Coatings During High-Temperature Oxidation

    Science.gov (United States)

    Chen, Wen-Long; Liu, Min; Zhang, Ji-Fu

    2016-12-01

    ZrO2-7 wt.%Y2O3 (7YSZ) thermal barrier coatings (TBCs) were prepared by atmospheric plasma spraying. High-temperature oxidation of 7YSZ TBCs was accomplished at 950 °C and characterized by impedance spectroscopy and scanning electron microscopy with energy-dispersive spectrometry. The results indicated that the thermally grown oxide (TGO) mainly contained alumina. The increase of the thickness of the TGO layer appeared to follow a parabolic law. Impedance analysis demonstrated that the resistance of the TGO increased with increasing oxidation time, also following a parabolic law, and that characterization of the TGO thickness based on fitting an equivalent circuit to its measured resistance is feasible. The YSZ grain-boundary resistance increased due to increasing cracks within the coating for oxidation time less than 50 h. However, beyond 150 h, the YSZ grain-boundary resistance slightly decreased, mainly due to sintering of the coating during the oxidation process.

  14. Preparation and characters of anode Ni-YSZ nanotubes of SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Meng, X.; Yang, N.; Tan, X. [Shandong Univ., Zibo (China). Dept. of Chemical Engineering

    2010-07-01

    Nickel/yttria-stabilized zirconia (Ni-YSZ) cermet composite nanotubes with a high specific surface area were synthesized using the sol-gel method with a porous anodic alumina oxide (AAO) as a template. X-ray diffraction (XRD) scanning electron microscopy (SEM), transmission electron microscopy (TEM) and BET measurements were conducted to characterize the samples. The catalytic performance of the Ni-YSZ nanotubes was also evaluated using a fixed bed reactor. The analyses demonstrated that the nanotubes were approximately 200 nm. The methane conversion rate was improved by approximately 10 per cent. Results of the study suggested that the Ni-YSZ nanotubes possessed a higher catalytic performance than other Ni-YSZ powders in relation to methane oxidation. The improved performance was attributed to the higher specific surface of the nanotubes. Results indicated that the nanotubes can be used in solid oxide fuel cell (SOFC) applications. 4 refs.

  15. Nano Ru Impregnated Ni-YSZ Anode as Carbon Resistance Layer for Direct Ethanol Solid Oxide Fuel Cells

    Institute of Scientific and Technical Information of China (English)

    SUN; Liangliang; ZHENG; Tao; HU; Zhimin; LUO; Linghong; WU; Yefan; XU; Xu; CHENG; Liang; SHI; Jijun

    2015-01-01

    Carbon formation on conventional Ni and Y2O3 stabilized zirconia(Ni/YSZ) anodes is a major problem for direct ethanol solid oxide fuel cells(DE-SOFC). A nanostructure Ru layer was grown in Ni/YSZ anodes through wet impregnation method with RuC l3 solvent at pH =4. Anode-supported Ni-YSZ/YSZ/(La0.8Sr0.2)0.98 MnO 3±δ(LSM) and Ru-Ni-YSZ/YSZ/LSM fuel cells were compared in terms of the performance and carbon formation with ethanol fuel. X-ray diffraction, scanning electron microscopy, energy disperse spectroscopy and electrochemical workstation were used to study the morphology and fuel cell performance. The results indicate that a nano structured and pearl like Ru layer was well dispersed on the surface of Ni-YSZ materials. The single cell with Ru-impregnated Ni/YSZ showed a maximum power density of 369 m W/cm at 750°C, which was higher than Ni-YSZ/YSZ/LSM. Specifically, no carbon was formed in the anode after 1000 min operation. Fuel cell performance and carbon resistance were enhanced with the addition of the Ru layer.

  16. Preparation and conductivity measurement of 7-8 mol % YSZ and 12 mol % CSZ for electrolyte SOFC

    Science.gov (United States)

    Budiana, B.; Fitriana, F.; Ayu, N.; Suasmoro, S.

    2016-08-01

    The study of 7YSZ (93% ZrO2-7%Y2O3), 8YSZ (92% ZrO2-8%Y2O3), and CSZ (88% ZrO2-12% CaO) as SOFC electrolytes have been carried out successfully. 7YSZ and 8YSZ powders were prepared by solid state reaction method of mixed Y2O3 and ZrO2 followed by calcination at 1350 °C for 1 hour, while CSZ was commercial products. Pellets of 7YSZ, 8YSZ, and CSZ were prepared by 1.2 gr, pressed at 40 MPa and sintered at 1550 °C for 4 hours. Rietveld refinement revealed that 7YSZ comprised 47.27% monoclinic, 52.65% cubic, and 0.008% Y2O3 cubic, while 8YSZ comprised 48.45% monoclinic, 49.32% cubic, 2.23% Y2O3 cubic and CSZ has 88% ZrO2 and 12% CaO. Ionic conductivity and activation energy were obtained from Cole- Cole Plot of impedance, the activation energy of 7YSZ=1.03eV, 8YSZ=0.96eV and CSZ=0.78eV.

  17. Nano Ru Impregnated Ni-YSZ Anode as Carbon Resistance Layer for Direct Ethanol Solid Oxide Fuel Cells

    Institute of Scientific and Technical Information of China (English)

    SUN Liangliang; ZHENG Tao; HU Zhimin; LUO Linghong; WU Yefan; XU Xu; CHENG Liang; SHI Jijun

    2015-01-01

    Carbon formation on conventional Ni and Y2O3stabilized zirconia (Ni/YSZ) anodes is a major problem for direct ethanol solid oxide fuel cells (DE-SOFC). A nanostructure Ru layer was grown in Ni/YSZ anodes through wet impregnation method with RuCl3solvent at pH=4. Anode-supported Ni-YSZ/YSZ/(La0.8Sr0.2)0.98MnO3±δ(LSM) and Ru-Ni-YSZ/YSZ/LSM fuel cells were compared in terms of the performance and carbon formation with ethanol fuel. X-ray diffraction, scanning electron microscopy,energy disperse spectroscopy and electrochemical workstation were used to study the morphology and fuel cell performance. The results indicate that a nano structured and pearl like Ru layer was well dispersed on the surface of Ni-YSZ materials. The single cell with Ru-impregnated Ni/YSZ showed a maximum power density of 369 mW/cmat 750°C, which was higher than Ni-YSZ/YSZ/LSM. Specifically, no carbon was formed in the anode after 1000 min operation. Fuel cell performance and carbon resistance were enhanced with the addition of the Ru layer.

  18. In operando Raman spectroscopy as a tool for investigation of solid oxide electrodes

    DEFF Research Database (Denmark)

    Traulsen, Marie Lund; Holtappels, Peter; Walker, Robert

    potential of combining in operando Raman spectroscopy with electrochemical characterisation, DTU Energy Conversion decided in 2014 to invest in a set-up dedicated to this purpose, At the end of the talk a short description will be given of this set-up, and the future plans will be described for combined...

  19. Electrochemical characterization of YSZ thick films deposited by dip-coating process

    Science.gov (United States)

    Mauvy, F.; Lenormand, P.; Lalanne, C.; Ansart, F.; Bassat, J. M.; Grenier, J. C.; Groupement de Recherches Cnrs "Pacte", Gdr 2985

    Yttria stabilized zirconia (YSZ, 8% Y 2O 3) thick films were coated on dense alumina substrates by a dip-coating process. The suspension was obtained by addition of a polymeric matrix in a stable suspension of commercial YSZ (Tosoh) powders dispersed in an azeotropic mixture MEK-EtOH. The suspension composition was improved by the addition of YSZ Tosoh particles encapsulated by zirconium alkoxide sol containing yttrium nitrate which are the precursors of the 8-YSZ oxide. This optimal formulation allowed preparing, via a dip-coating process, thick films which were, after thermal treatment, homogeneous, dense and crack-free. A specific method was performed to measure the electrical conductivity, i.e. to determine the ionic conductivity of the film: it uses the four-point probe technique combined with ac impedance spectroscopy. The good agreement between the classical two-electrode measurements performed on YSZ pellets and the four-electrode ones performed on YSZ films allows concluding that this method is relevant for characterizing the transport properties of thick films.

  20. Hydrogen Solubility in Pr-doped and Un-doped YSZ for One Chamber Fuel Cell

    DEFF Research Database (Denmark)

    Bay, Lasse; Horita, T.; Sakai, N.;

    1998-01-01

    SIMS analysis. Doping of Pr in the YSZ resulted in a higher intensity of the D ion, which indicated that hydrogen solubility was raised by the doping. The solubility of hydrogen in the electrolyte may affect the performance of one chamber fuel cells. (C) 1998 Elsevier Science B.V. All rights reserved.......Yttria-stabilised zirconia electrolytes (YSZ and Pr-doped YSZ) and yttria-doped strontium cerate (SYC) were tested in a one chamber fuel cell fed with a mixture of methane and air at 1223 K. The obtained performances were 4 mW cm(-2), 3 mW cm(-2), 2.5 mW cm(-2), and 0.15 mW cm(-2) for SYC, 1.8 mol.......% Pr-doped YSZ, 17 mol.% Pr-doped YSZ, and un-doped YSZ, respectively. These values are lower than those reported by Asano ct al., due to poisoning of the gold electrode. The solubility of hydrogen in the electrolytes was compared by means of tracer exchange using a H(2) + D(2)O mixture and subsequent...

  1. Electrochemical characterization of YSZ thick films deposited by dip-coating process

    Energy Technology Data Exchange (ETDEWEB)

    Mauvy, F.; Lalanne, C.; Bassat, J.M.; Grenier, J.C. [Institut de Chimie de la Matiere Condensee de Bordeaux ICMCB - CNRS, Universite Bordeaux 1, 87, av. du Dr. A. Schweitzer, 33 608 Pessac-Cedex (France); Lenormand, P.; Ansart, F. [Centre Interuniversitaire de Recherche et d' Ingenierie et d' Ingenierie des Materiaux, CIRIMAT, Universite Paul Sabatier, Bat. 2R1, 118 route de Narbonne, 31062 Toulouse Cedex (France)

    2007-09-27

    Yttria stabilized zirconia (YSZ, 8% Y{sub 2}O{sub 3}) thick films were coated on dense alumina substrates by a dip-coating process. The suspension was obtained by addition of a polymeric matrix in a stable suspension of commercial YSZ (Tosoh) powders dispersed in an azeotropic mixture MEK-EtOH. The suspension composition was improved by the addition of YSZ Tosoh particles encapsulated by zirconium alkoxide sol containing yttrium nitrate which are the precursors of the 8-YSZ oxide. This optimal formulation allowed preparing, via a dip-coating process, thick films which were, after thermal treatment, homogeneous, dense and crack-free. A specific method was performed to measure the electrical conductivity, i.e. to determine the ionic conductivity of the film: it uses the four-point probe technique combined with ac impedance spectroscopy. The good agreement between the classical two-electrode measurements performed on YSZ pellets and the four-electrode ones performed on YSZ films allows concluding that this method is relevant for characterizing the transport properties of thick films. (author)

  2. Conformation of LSM/YSZ and LSM ceramic films obtained by the citrate and solid mixture techniques; Conformacao de filmes ceramicos de LSM e LSM/YSZ obtidos pelas tecnicas citratos e mistura de solidos

    Energy Technology Data Exchange (ETDEWEB)

    Chiba, R.; Vargas, R.A.; Andreoli, M.; Seo, E.S.M., E-mail: rchiba@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (CCTM/IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Ciencia e Tecnologia de Materiais. Lab. de SOFC - Insumos e Componentes

    2009-07-01

    In this work, the ceramic films of LSM/YSZ (strontium-doped lanthanum manganite/Yttria-stabilized zirconia) and LSM used as cathodes of the solid oxide fuel cells (SOFC) are conformed by the wet powder spraying technique. The composite LSM/YSZ was obtained by the solid mixture technique and LSM by the citrate technique. For the formation of the LSM/YSZ and LSM ceramic films was necessary the preparation of dispersed ceramic suspensions for the deposition in YSZ substrate, used as electrolyte of the CaCOS. These powders were conformed using an aerograph for the deposition of the LSM/YSZ and LSM thin films of approximately 40 microns. The half-cells had been characterized by X-ray diffractometry (XRD), identifying the phases hexagonal (LSM) and cubica (YSZ). And electronic scanning electron microscopy (SEM) was used to evaluate the adherence and porosity of the ceramic films according to the characteristics of the cathode. (author)

  3. Effect of sputter deposited YSZ thin films on the fracture behavior of dental bioceramics

    Science.gov (United States)

    Teixeira, Erica Cappelletto Nogueira

    The fracture behavior of dental bioceramic materials was evaluated under physiologic conditions when modified by yttria stabilized zirconia (YSZ) thin film deposition. It was hypothesized that changing the YSZ thin film properties will produce a significant enhancement in the strength of bioceramic materials, ultimately promoting a more fatigue resistant construct. Porcelain, alumina, and zirconia were evaluated in terms of dynamic fatigue for an initial characterization of their fracture behavior. Data showed that strength degradation occurred in all three materials, most drastically in porcelain. Initial strength measurements, focused on depositing YSZ thin films on three unique substrates; porcelain, alumina, and zirconia, were carried out. A significant increase in strength was observed for alumina and porcelain. Since strength alone is not enough to characterize the fracture behavior of brittle materials, coated specimens of porcelain and zirconia were subjected to dynamic fatigue and Weibull analysis. Coated YSZ porcelain specimens showed a significant increase in strength at all tested stressing rates. YSZ coated zirconia specimens showed similar strength values at all stressing rates. The effect of film thickness on porcelain was also evaluated. Data demonstrated that film thickness alone does not appear to control increases in the flexural strength of a modified substrate. It is expected that deposition induced stress in YSZ sputtered films does not change with film thickness. However, a thicker film will generate a larger force at the film/substrate interface, contributing to delamination of the film. It was clear that in order to have a significant improvement in the fracture behavior of porcelain, changing the thickness of the film is not enough. The columnar structure of the YSZ films developed seems to favor an easy path for crack propagation limiting the benefits expected by the coating. The effect of a multilayered film, composed by brittle

  4. YSZ thin films with minimized grain boundary resistivity

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Edmund M.; Kleine-Boymann, Matthias; Janek, Juergen; Yang, Hao; Browning, Nigel D.; Takamura, Yayoi; Kim, Sangtae

    2016-03-31

    In recent years, interface engineering of solid electrolytes has been explored to increase their ionic conductivity and improve the performance of solid oxide fuel cells and other electrochemical power sources. It has been observed that the ionic conductivity of epitaxially grown thin films of some electrolytes is dramatically enhanced, which is often attributed to effects (e. g. strain-induced mobility changes) at the heterophase boundary with the substrate. Still largely unexplored is the possibility of manipulation of grain boundary resistivity in polycrystalline solid electrolyte films, clearly a limiting factor in their ionic conductivity. Here we report that the ionic conductivity of yttria stabilized zirconia thin films with nano-­ columnar grains grown on a MgO substrate nearly reaches that of the corresponding single crystal when the thickness of the films becomes less than roughly 8 nm (smaller by a factor of three at 500°C). Using impedance spectroscopy, the grain boundary resistivity was probed as a function of film thickness. The resistivity of the grain boundaries near the film- substrate interface and film surface (within 4 nm of each) was almost entirely eliminated. This minimization of grain boundary resistivity is attributed to Mg2+ diffusion from the MgO substrate into the YSZ grain boundaries, which is supported by time of flight secondary ion mass spectroscopy measurements. We suggest grain boundary “design” as an attractive method to obtain highly conductive solid electrolyte thin films.

  5. Continuous Process for Low-Cost, High-Quality YSZ Powder

    Energy Technology Data Exchange (ETDEWEB)

    Scott L. Swartz; Michael Beachy; Matthew M. Seabaugh

    2006-03-31

    This report describes results obtained by NexTech Materials, Ltd. in a project funded by DOE under the auspices of the Solid-State Energy Conversion Alliance (SECA). The project focused on development of YSZ electrolyte powder synthesis technology that could be ''tailored'' to the process-specific needs of different solid oxide fuel cell (SOFC) designs being developed by SECA's industry teams. The work in the project involved bench-scale processing work aimed at establishing a homogeneous precipitation process for producing YSZ electrolyte powder, scaleup of the process to 20-kilogram batch sizes, and evaluation of the YSZ powder products produced by the process. The developed process involved the steps of: (a) preparation of an aqueous hydrous oxide slurry via coprecipitation; (b) washing of residual salts from the precipitated hydroxide slurry followed by drying; (c) calcination of the dried powder to crystallize the YSZ powder and achieve desired surface area; and (d) milling of the calcined powder to targeted particle size. YSZ powders thus prepared were subjected to a comprehensive set of characterization and performance tests, including particle size distribution and surface area analyses, sintering performance studies, and ionic conductivity measurements. A number of different YSZ powder formulations were established, all of which had desirable performance attributes relative to commercially available YSZ powders. Powder characterization and performance metrics that were established at the onset of the project were met or exceeded. A manufacturing cost analysis was performed, and a manufactured cost of $27/kg was estimated based on this analysis. The analysis also allowed an identification of process refinements that would lead to even lower cost.

  6. Thermal shock behavior of toughened gadolinium zirconate/YSZ double-ceramic-layered thermal barrier coating

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Xinghua, E-mail: xhzhong@mail.sic.ac.cn; Zhao, Huayu; Zhou, Xiaming; Liu, Chenguang; Wang, Liang; Shao, Fang; Yang, Kai; Tao, Shunyan; Ding, Chuanxian

    2014-04-01

    Highlights: • Gd{sub 2}Zr{sub 2}O{sub 7}/YSZ DCL thermal barrier coating was designed and fabricated. • The Gd{sub 2}Zr{sub 2}O{sub 7} top ceramic layer was toughened by addition of nanostructured 3YSZ. • Remarkable improvement in thermal shock resistance of the DCL coating was achieved. - Abstract: Double-ceramic-layered (DCL) thermal barrier coating system comprising of toughened Gadolinium zirconate (Gd{sub 2}Zr{sub 2}O{sub 7}, GZ) as the top ceramic layer and 4.5 mol% Y{sub 2}O{sub 3} partially-stabilized ZrO{sub 2} (4.5YSZ) as the bottom ceramic layer was fabricated by plasma spraying and thermal shock behavior of the DCL coating was investigated. The GZ top ceramic layer was toughened by addition of nanostructured 3 mol% Y{sub 2}O{sub 3} partially-stabilized ZrO{sub 2} (3YSZ) to improve fracture toughness of the matrix. The thermal shock resistance of the DCL coating was enhanced significantly compared to that of single-ceramic-layered (SCL) GZ-3YSZ composite coating, which is believed to be primarily attributed to the two factors: (i) the increase in fracture toughness of the top ceramic layer by incorporating nanostructured YSZ particles and (ii) the improvement in strain tolerance through the utilization of 4.5YSZ as the bottom ceramic layer. In addition, the failure mechanisms are mainly attributed to the still low fracture toughness of the top ceramic layer and oxidation of the bond-coat.

  7. Operando X-ray investigation of solid oxide fuel cell model electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Volkov, Sergey Aleksandrovic

    2017-04-15

    A detailed study of three solid oxide fuel cells (SOFCs) related model systems is presented in this work with the aim of the better understanding of the structural changes in cell components associated with their operation. The first model system is an La{sub 0.6}Sr{sub 0.4}CoO{sub 3-d} (LSC) on yttria-stabilized zirconia (YSZ). Changes in the YSZ(100) single crystal surface structure buried under the squared LSC microelectrode were studied at a synchrotron under operational conditions. High flux photon beam at the synchrotron allowed access to the LSC/YSZ interface. Structural information from the substrate surface at an atomic scale was acquired. Element-specific anomalous XRD data allowed to distinguish between Y and Zr scattering contributions. For the first time, it was shown that the Y cation concentration at the electrode/electrolyte interface strongly depends on the sample environment and the applied potential. The second model system is a Pt/YSZ. Buried YSZ(111) surface and dense Pt film morphology changes under operational conditions were addressed. High-energy X-rays were necessary to collect surface-sensitive information from the interface due to highly absorbing Pt film. The main conclusion is - under conditions applied, the YSZ single crystal surface remains stable at an atomic level. A nagging topic of the Pt ''phase oxide'' formation at the Pt/YSZ interface during anodic polarization was also raised. Although XRD data did not show a clear evidence of PtO{sub x} presence at the interface, energy-dispersive X-ray analysis of the film cross-cut profile after the synchrotron experiment revealed distinct oxygen signal from delaminated parts of the film. Last but not least, the structure of a ZrO{sub 2} ultrathin film grown on a Pt{sub 3}Zr(0001) single crystal was studied in ultra-high vacuum for the first time be means of SXRD. This model system is aiming to improve understanding of the electrolyte materials based on ZrO{sub 2} (e

  8. The Influence Of The Way Of Alumina Addition On Properties Improvement Of 3YSZ Material

    Directory of Open Access Journals (Sweden)

    Drożdż E.

    2015-06-01

    Full Text Available Yttria-stabilized zirconia (YSZ is the best known ceramic-oxide material employed as a component of either solid electrolyte or anode cermet material for intermediate solid oxide fuel cell (IT - SOFC. The properties of traditionally produced (by mechanical mixing of oxides Al2O3/3YSZ composite with the same composition materials obtained by citrate and impregnation methods and with properties of pure tetragonal zirconia (3YSZ were compared. The materials were characterised by X-ray diffraction, SEM observations with EDX analysis, density and impedance spectroscopy measurements. The results shown that Al2O3/3YSZ composites reveals higher conductivity than pure 3YSZ and that addition of alumina (regardless of methods improve electric properties of resulting materials. Taking into account application of this materials as anode in IT-SOFC the determined values of energy activation of conductivity and microstructural properties of composites show that materials obtained by citric method are the most promising.

  9. Structural study of metastable tetragonal YSZ powders produced via a sol-gel route

    Energy Technology Data Exchange (ETDEWEB)

    Viazzi, Celine [CIRIMAT, Paul Sabatier University, 118 Rte de Narbonne, 31 062 Toulouse Cedex 09 (France)], E-mail: viazzi@chimie.ups-tlse.fr; Bonino, Jean-Pierre; Ansart, Florence; Barnabe, Antoine [CIRIMAT, Paul Sabatier University, 118 Rte de Narbonne, 31 062 Toulouse Cedex 09 (France)

    2008-03-20

    Sol-gel yttria stabilized zirconia (YSZ) is investigated in this paper. The final aim is to process YSZ powders into stable slurries in order to prepare thick coatings for thermal barrier to be applied on hot turboengine components. In fact, this system is well-known for its excellent thermomechanical resistance at elevated temperatures but the relationship between these performances and the structural and microstructural characteristics of these materials is not fully understood. This paper reports a preliminary study concerning recent progress on the structural properties control of YSZ powders synthesized by sol-gel process and the main advantages of this process compared to conventional methods. As a first step towards this understanding, structural investigations of ZrO{sub 2} doped with various xmol%YO{sub 1.5} coatings, have been performed using X-ray diffraction, structural Rietveld refinement, Raman spectra analysis and transmission electron microscopy. The evolution of the crystallographic structure of YSZ powders after air annealing at various temperatures 1100 deg. C, 1200 deg. Cand 1400 deg. C was studied to well understand the conditions of the formation of desired metastable tetragonal phase (t'). Then, this work should allow to correlate chemical and thermomechanical parameters as YSZ formulation and sol-gel elaboration conditions, temperature and t' phase performances.

  10. In situ and operando spectroscopic studies of sonically aided catalysts for biogas exhaust abatement

    Science.gov (United States)

    Jodłowski, P. J.; Chlebda, D.; Piwowarczyk, E.; Chrzan, M.; Jędrzejczyk, R. J.; Sitarz, M.; Węgrzynowicz, A.; Kołodziej, A.; Łojewska, J.

    2016-12-01

    The aim of this study was to test sonochemical method to modify surface of catalysts to obtain highly dispersed and active materials for methane combustion. The catalysts were characterised by various physicochemical characterisation methods including: DLS, BET nitrogen adsorption, SEM, EDX and ED-XRF. The results of classical surface analyses and catalytic tests were correlated with the operando DRIFT/MS spectroscopy results. The sonochemical preparation method has proven an efficient way to obtain the active catalysts for methane catalytic combustion. The chromium oxide catalyst has revealed great activity compared to the commercially used palladium catalysts. The DRIFT/MS operando analyses have proven that the formate intermediates at the catalyst surface are stable during methane catalytic combustion.

  11. Degradation analysis of 18650-type lithium-ion cells by operando neutron diffraction

    Science.gov (United States)

    Shiotani, Shinya; Naka, Takahiro; Morishima, Makoto; Yonemura, Masao; Kamiyama, Takashi; Ishikawa, Yoshihisa; Ukyo, Yoshio; Uchimoto, Yoshiharu; Ogumi, Zempachi

    2016-09-01

    In-situ and operando neutron diffraction are used to analyze the degradation of 18650-type Li-ion cells. Structural characterization of the electrode materials is performed by applying the Rietveld refinement technique to the in-situ data. The structural refinement of both electrodes in the degraded cells indicates that the amount of active Li-ions is reduced by 14.4% and 13.7% in the cathode and anode, respectively. This reduction is good in agreement with the capacity loss determined electrochemically. The results suggest that capacity loss might be mainly caused by loss of active Li-ions due to side reactions such as solid electrolyte interface (SEI) growth. Furthermore, operando measurements are performed to examine the deterioration of the electrode and active materials. Because the structural evolution depending on capacity is increased in the cathode of degraded cells, it is presumed that the cathode active material has deteriorated due to phase transitions.

  12. Emerging operando and x-ray pair distribution function methods for energy materials development

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, Karena W.

    2016-03-01

    Our energy needs drive widespread materials research. Advances in materials characterization are critical to this research effort. Using new characterization tools that allow us to probe the atomic structure of energy materials in situ as they operate, we can identify how their structure is linked to their functional properties and performance. These fundamental insights serve as a roadmap to enhance performance in the next generation of advanced materials. In the last decade, developments in synchrotron instrumentation have made the pair distribution function (PDF) method and operando x-ray studies more readily accessible tools capable of providing valuable insights into complex materials systems. Here, the emergence of the PDF method as a versatile structure characterization tool and the further enhancement of this method through developments in operando capabilities and multivariate data analytics are described. These advances in materials characterization are demonstrated by several highlighted studies focused on energy storage in batteries.

  13. Modifications of interface chemistry of LSM–YSZ composite by ceria nanoparticles

    DEFF Research Database (Denmark)

    Knöfel, Christina; Wang, Hsiang-Jen; Thydén, Karl Tor Sune

    2011-01-01

    A porous composite electrode LSM–YSZ (lanthanum strontium manganite and yttria stabilized zirconia) was impregnated with different amounts of SDC (samarium substituted ceria) nanoparticles. The materials were investigated with X-ray diffraction, scanning electron microscopy, transmission electron...... to the applied nanoparticle impregnation method. It is indicated that interactions between surfactant, nanoparticles, impregnation solution and the LSM–YSZ composite take place which can locally affect the surface and interface chemistry of the investigated materials....... microscopy and X-ray photoelectron spectroscopy to determine the microstructure, the interface chemistry and the surface chemistry of the various impregnated samples. The SDC nanoparticles cover the surface of the LSM–YSZ backbone to a large extent; they are approximately 5–20 nm in diameter and have a cubic...

  14. Cu-Ni-YSZ anodes for solid oxide fuel cell by mechanical alloying processing

    Energy Technology Data Exchange (ETDEWEB)

    Guisard Restivo, Thomaz A.; Mello-Castanho, Sonia R.H. [IPEN, Inst. of Energetic and Nuclear Research, Sao Paulo, SP (Brazil)

    2010-01-15

    The work shows some results concerning a new cermet material 40 vol.% [(Cu)-Ni]-YSZ processed by mechanical alloying followed by Sintering by Activated Surface method. The projected cermet microstructure for this application is expected to possess microstructural characteristics that lead to better electric and ionic percolating, higher electrocatalytic activity and fuel reforming. The powder samples prepared by mechanical alloying optimized conditions show a homogeneous mixture. Transmission and scanning electron microscope analysis have demonstrated the powder particles are nanosized after 2 h of milling, showing lamellar internal structure aggregates. Suitable sintered pellets are obtained from these powders, within the required porosity and microstructure. Sintering kinetics studies for pellets of Ni-YSZ and Ni-Cu-YSZ indicate 2-step sintering processes. Copper additive promotes sintering and refines the microstructure. (orig.)

  15. Microstructural Degradation of Ni/YSZ Electrodes in Solid Oxide Electrolysis Cells under High Current

    DEFF Research Database (Denmark)

    Chen, Ming; Liu, Yi-Lin; Bentzen, Janet Jonna;

    2013-01-01

    ). Detailed post-mortem characterizations were carried out to investigate microstructural changes after long-term galvanostatic tests, focusing on the Ni/YSZ electrode. Formation of ZrO2 nano-particles on Ni surfaces was observed in cells exposed to −1 or −1.5 A/cm2 at 800 or 850°C, but not in those tested...... of Ni-YSZ interfacial reactions, taking place under the conditions prevailing under strong polarization. A mechanism for the formation of ZrO2 nano-particles on the Ni surface under the electrolysis cell testing is proposed and the possibility of Ni-YSZ interfacial reactions under such conditions (T, p(O...

  16. SOFC LSM:YSZ cathode degradation induced by moisture: An impedance spectroscopy study

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Mogensen, Mogens Bjerg

    2011-01-01

    The cause of the degradation effect of moisture during operation of LSM cathode based SOFCs has been investigated by means of a detailed impedance characterization on LSM:YSZ composite cathode based SOFCs. Further the role of YSZ as cathode composite material was studied by measurements on SOFCs...... with a LSM:CGO composite cathode on a CGO interdiffusion barrier layer. It was found that both types of cathodes showed similar electrochemical characteristics towards the presence of moisture during operation. Upon addition and removal of moisture in the fed air the impedance study showed a change...... in the high frequency cathode arc, which is associated with the charge transport/transfer at the LSM/YSZ interface. On prolonged operation with the presence of moisture an ongoing increase in the high frequency cathode arc resulted in a permanent loss of cathode/electrolyte contact and thus increase...

  17. Growth and micro structural studies on Yittria Stabilized Zirconia (YSZ) and Strontium Titanate (STO) buffer layers

    Science.gov (United States)

    Srinivas, S.; Pinto, R.; Pai, S. P.; Dsousa, D. P.; Apte, P. R.; Kumar, D.; Purandare, S. C.; Bhatnagar, A. K.

    1995-01-01

    Microstructure of Yittria Stabilized Zirconia (YSZ) and Strontium Titanate (STO) of radio frequency magnetron sputtered buffer layers was studied at various sputtering conditions on Si (100), Sapphire and LaAlO3 (100) substrates. The effect of substrate temperatures up to 800 C and sputtering gas pressures in the range of 50 mTorr. of growth conditions was studied. The buffer layers of YSZ and STO showed a strong tendency for columnar growth was observed above 15 mTorr sputtering gas pressure and at high substrate temperatures. Post annealing of these films in oxygen atmosphere reduced the oxygen deficiency and strain generated during growth of the films. Strong c-axis oriented superconducting YBa2Cu3O7-x (YBCO) thin films were obtained on these buffer layers using pulsed laser ablation technique. YBCO films deposited on multilayers of YSZ and STO were shown to have better superconducting properties.

  18. Multilayer Thermal Barrier Coating (TBC) Architectures Utilizing Rare Earth Doped YSZ and Rare Earth Pyrochlores

    Science.gov (United States)

    Schmitt, Michael P.; Rai, Amarendra K.; Bhattacharya, Rabi; Zhu, Dongming; Wolfe, Douglas E.

    2014-01-01

    To allow for increased gas turbine efficiencies, new insulating thermal barrier coatings (TBCs) must be developed to protect the underlying metallic components from higher operating temperatures. This work focused on using rare earth doped (Yb and Gd) yttria stabilized zirconia (t' Low-k) and Gd2Zr2O7 pyrochlores (GZO) combined with novel nanolayered and thick layered microstructures to enable operation beyond the 1200 C stability limit of current 7 wt% yttria stabilized zirconia (7YSZ) coatings. It was observed that the layered system can reduce the thermal conductivity by approximately 45 percent with respect to YSZ after 20 hr of testing at 1316 C. The erosion rate of GZO is shown to be an order to magnitude higher than YSZ and t' Low-k, but this can be reduced by almost 57 percent when utilizing a nanolayered structure. Lastly, the thermal instability of the layered system is investigated and thought is given to optimization of layer thickness.

  19. Determination of Three Dimensional Microstructure Parameters from a Solid Oxide Ni/YSZ Electrode after Electrolysis Operation

    DEFF Research Database (Denmark)

    Jørgensen, Peter Stanley; Bowen, Jacob R.

    2011-01-01

    The interface structure of a Ni/YSZ electrode tested for 1300 hours in steam electrolysis mode is analyzed. We break down the electrode interface structure measurements into total phase interfaces (e.g. total pore surface area), two-phase interfaces (e.g. Ni/YSZ interface area) and triple...

  20. Examination of charge transfer in Au/YSZ for high-temperature optical gas sensing

    Energy Technology Data Exchange (ETDEWEB)

    Baltrus, John P. [U.S. DOE; Ohodnicki, Paul R. [U.S. DOE

    2014-01-01

    Au-nanoparticle incorporated oxide thin film materials demonstrate significant promise as functionalsensor materials for high temperature optical gas sensing in severe environments relevant for fossil andnuclear based power generation. The Au/yttria-stabilized zirconia (YSZ) system has been extensivelystudied in the literature and serves as a model system for fundamental investigations that seek to betterunderstand the mechanistic origin of the plasmonic gas sensing response. In this work, X-ray photoelec-tron spectroscopy techniques are applied to Au/YSZ films in an attempt to provide further experimentalevidence for a proposed sensing mechanism involving a change in free carrier density of Au nanoparticles due to charge transfer.

  1. Oxidation resistance of the nanostructured YSZ coating on the IN-738 superalloy

    Directory of Open Access Journals (Sweden)

    Ahmad Keyvani

    2014-12-01

    Full Text Available Conventional and nanostructured YSZ coatings were deposited on the IN-738 Ni super alloy by the atmospheric plasma spray technique. The oxidation was measured at 1100°C in an atmospheric electrical furnace. According to the experimental results the nanostructured coatings showed a better oxidation resistance than the conventional ones. The improved oxidation resistance of the nanocoating could be explained by the change in structure to a dense and more packed structure in this coating. The mechanical properties of the coatings were tested using the thermal cyclic, nanoindentation and bond strength tests, during which the nanostructured YSZ coating showed a better performance by structural stability.

  2. Aspects of Metal-YSZ Electrode Kinetics Studied using Model Electrodes

    DEFF Research Database (Denmark)

    Graves, Christopher R.; Ebbesen, Sune; Mogensen, Mogens Bjerg

    2009-01-01

    The electrode kinetics of oxidation and reduction of H2/H2O and CO/CO2 at the metal/yttria stabilized zirconia (YSZ) interface were studied using model metal wire electrodes contacting polished YSZ pellets. The intent was to probe the reaction mechanisms by comparing the same reactions using...... different metals (Ag, Au, Cu, Ni, Pd, and Pt) under identical conditions relevant to fuel cell and electrolysis cell operation (e.g. including 50% H2/H2O and 50% CO/CO2). Impedance spectra were measured at open-circuit voltage and under polarization, and polarization sweeps were performed. The gas...

  3. Ni/YSZ electrode degradation studied by impedance spectroscopy: Effects of gas cleaning and current density

    DEFF Research Database (Denmark)

    Hauch, Anne; Mogensen, Mogens Bjerg

    2010-01-01

    Anode supported (Ni/YSZ–YSZ–LSM/YSZ) solid oxide fuel cells were tested and the degradation over time was monitored and analyzed by impedance spectroscopy. Test conditions were chosen to focus on the anode degradation and all tests were operated at 750 °C. O2 was supplied to the cathode and the a......Anode supported (Ni/YSZ–YSZ–LSM/YSZ) solid oxide fuel cells were tested and the degradation over time was monitored and analyzed by impedance spectroscopy. Test conditions were chosen to focus on the anode degradation and all tests were operated at 750 °C. O2 was supplied to the cathode...

  4. Improving thermal insulation of TC4 using YSZ-based coating and SiO2 aerogel

    Institute of Scientific and Technical Information of China (English)

    Lei Jin; Peizhong Li; Haibin Zhou; Wei Zhang; Guodong Zhou; Chun Wang

    2015-01-01

    In this paper, air plasmas spray (APS) was used to prepare YSZ and Sc2O3–YSZ (ScYSZ) coating in order to improve the thermal insulation ability of TC4 alloy. SiO2 aerogel was also synthesized and affixed on TC4 titanium alloy to inhabit thermal flow. The microstructures, phase compositions and thermal insulation performance of three coatings were analyzed in detail. The results of thermal diffusivity test by a laser flash method showed that the thermal diffusivities of YSZ, Sc2O3–YSZ and SiO2 aerogel are 0.553, 0.539 and 0.2097 ? 10 ? 6 m2/s, respectively. Then, the thermal insulation performances of three kinds of coating were investigated from 20 1C to 400 1C using high infrared radiation heat flux technology. The experimental results indicated that the corresponding temperature difference between the top TC4 alloy (400 1C) and the bottom surface of YSZ is 41.5 1C for 0.6 mm thickness coating. For 1 mm thickness coating, the corresponding temperature difference between the top TC4 alloys (400 1C) and the bottom surface of YSZ, ScYSZ, SiO2 aerogel three specimens is 54, 54.6 and 208 1C, respectively. The coating thickness and species were found to influence the heat insulation ability. In these materials, YSZ and ScYSZ exhibited a little difference for heat insulation behavior. However, SiO2 aerogel was the best one among them and it can be taken as protection material on TC4 alloys. In outer space, SiO2 aerogel can meet the need of thermal insulation of TC4 of high-speed aircraft.

  5. Improving thermal insulation of TC4 using YSZ-based coating and SiO2 aerogel

    Directory of Open Access Journals (Sweden)

    Lei Jin

    2015-04-01

    Full Text Available In this paper, air plasmas spray (APS was used to prepare YSZ and Sc2O3–YSZ (ScYSZ coating in order to improve the thermal insulation ability of TC4 alloy. SiO2 aerogel was also synthesized and affixed on TC4 titanium alloy to inhabit thermal flow. The microstructures, phase compositions and thermal insulation performance of three coatings were analyzed in detail. The results of thermal diffusivity test by a laser flash method showed that the thermal diffusivities of YSZ, Sc2O3–YSZ and SiO2 aerogel are 0.553, 0.539 and 0.2097×10−6 m2/s, respectively. Then, the thermal insulation performances of three kinds of coating were investigated from 20 °C to 400 °C using high infrared radiation heat flux technology. The experimental results indicated that the corresponding temperature difference between the top TC4 alloy (400 °C and the bottom surface of YSZ is 41.5 °C for 0.6 mm thickness coating. For 1 mm thickness coating, the corresponding temperature difference between the top TC4 alloys (400 °C and the bottom surface of YSZ, ScYSZ, SiO2 aerogel three specimens is 54, 54.6 and 208 °C, respectively. The coating thickness and species were found to influence the heat insulation ability. In these materials, YSZ and ScYSZ exhibited a little difference for heat insulation behavior. However, SiO2 aerogel was the best one among them and it can be taken as protection material on TC4 alloys. In outer space, SiO2 aerogel can meet the need of thermal insulation of TC4 of high-speed aircraft.

  6. NiO Nanofibers as a Candidate for a Nanophotocathode

    Directory of Open Access Journals (Sweden)

    Thomas J. Macdonald

    2014-04-01

    Full Text Available p-type NiO nanofibers have been synthesized from a simple electrospinning and sintering procedure. For the first time, p-type nanofibers have been electrospun onto a conductive fluorine doped tin oxide (FTO surface. The properties of the NiO nanofibers have been directly compared to that of bulk NiO nanopowder. We have observed a p-type photocurrent for a NiO photocathode fabricated on an FTO substrate.

  7. Ni/YSZ electrodes structures optimized for increased electrolysis performance and durability

    DEFF Research Database (Denmark)

    Hauch, Anne; Brodersen, Karen; Chen, Ming

    2016-01-01

    ) the three phases (Ni, YSZ and pore phase) shall be size-matched and well-dispersed. Applying such microstructure optimized Ni/YSZ electrode we show SOEC test results with long-term degradation rate as low as 0.3-0.4%/kh at - 1 A/cm2, 800 °C and inlet gas mixture of p(H2O)/p(H2):90/10. This enables SOEC...... and the resulting electrochemical performance both initially and during long-term electrolysis testing at high current density and high p(H2O) inlet. Especially, this work focuses on microstructure optimization to hinder Ni mobility and migration during long-term operation and illustrates the key-role of electrode...... over-potential on the degradation of the Ni/YSZ electrodes in SOEC. We find that for long-term stability for electrolysis at high current densities and high p(H2O) the as-produced NiO/YSZ precursor electrode should be: 1) As dense as possible, 2) as fine particle and pore sized as possible and 3...

  8. The effect of the presence of fine YSZ particles on the performance of porous nickel electrodes

    NARCIS (Netherlands)

    Boer, de B.; Gonzalez, M.; Bouwmeester, H.J.M.; Verweij, H.

    2000-01-01

    The electrochemical performance of a porous nickel electrode with its surface modified by deposition with fine yttria-stabilised zirconia (YSZ) powder is compared with that of the ‘bare’ electrode. Image analysis of the electrode microstructure yields values for the triple phase boundary (TPB) lengt

  9. Preconditioning of the YSZ-NiO Fuel Cell Anode in Hydrogenous Atmospheres Containing Water Vapor

    Science.gov (United States)

    Vasyliv, Bogdan; Podhurska, Viktoriya; Ostash, Orest

    2017-04-01

    The YSZ-NiO ceramics for solid oxide fuel cells (SOFCs) anode have been investigated. A series of specimens were singly reduced in a hydrogenous atmosphere (Ar-5 vol% H2 mixture) at 600 °C under the pressure of 0.15 MPa or subjected to `reduction in the mixture-oxidation in air' (redox) cycling at 600 °C. The YSZ-Ni cermets formed in both treatment conditions were then aged in `water vapor in Ar-5 vol% H2 mixture' atmosphere at 600 °C under the pressure of 0.15 MPa. Additionally, the behaviour of the as-received material in this atmosphere was studied. It was revealed that small amount of water vapor in Ar-5 vol% H2 mixture (water vapor pressure below 0.03 MPa) does not affect the reduction of the nickel phase in the YSZ-NiO ceramics, but causes some changes in the YSZ-Ni cermet structure. In particular, nanopore growth in tiny Ni particles takes place. At higher concentration of water vapor in the mixture (water vapor pressure above 0.03-0.05 MPa), converse changes in the kinetics of reduction occur. The best physical and mechanical properties were revealed for the material treated by redox cycling after holding at 600 °C in water depleted gas mixture. The dual effect of water vapor on nickel-zirconia anode behaviour is discussed basing on scanning electron microscopy analysis data, material electrical conductivity, and strength.

  10. Phenomenological Treatment of the Inductive Hysteresis in the Cathode Reaction on YSZ Electrolytes

    DEFF Research Database (Denmark)

    Bay, Lasse; Zachau-Christiansen, Birgit; Jacobsen, Torben

    1999-01-01

    The cathode reaction on YSZ electrolytes shows inductive hysteresis behavior with an activation/deactivation process of the cell. This is described by a phenomenological model, where the rate of activation is proportional to the current density and the rate of deactivation is proportional...

  11. Relation between powder size and electrolyte properties in nano YSZ system

    Institute of Scientific and Technical Information of China (English)

    Minfang Han; Lijun Huo; Botao Li; Suping Peng

    2005-01-01

    YSZ (yttria stabilized zirconia) electrolyte properties made from different sizes of nano powders were investigated. As a result, the sample marked KD with the smallest size (10 nm) of first particles and the sample marked TH with narrow distribution and the smallest median diameter Mmed of 0.49 μm have the best sintering properties and the highest electrical conductivity. There is a very well correlation between the density and the electrical conductivity of YSZ, that is, the samples with a higher density have a higher electrical conductivity. The area resistance of YSZ electrolyte made in the experiment, such as TH of 0.483 Ω.cm2, is much lower than that of the sample D of 1.300 Ω.cm2 made in Germany at 850℃. The complex resistance of YSZ electrolyte made in the experiment at the grain, grain boundary and electrode in the range of 300-750℃ decreases greatly compared to the sample made in Germany by shown in the complex impedance plot.

  12. Redox stability of SOFC: Thermal analysis of Ni-YSZ composites

    DEFF Research Database (Denmark)

    Pihlatie, Mikko; Kaiser, Andreas; Mogensen, Mogens Bjerg

    2009-01-01

    A re-oxidation of a Ni-based SOFC can seriously damage the cells. Important aspects of this thermomechanical instability are reduction–oxidation kinetics and the dimensional behaviour of the Ni–YSZ composites. These were investigated in the temperature range of 600–1000 °C and different combinati...

  13. Electromotive Potential Distribution and Electronic Leak Currents in Working YSZ Based SOCs

    DEFF Research Database (Denmark)

    Mogensen, Mogens Bjerg; Jacobsen, Torben

    2009-01-01

    The size of electronic leak currents through the YSZ electrolyte of solid oxide cells have been calculated using basic solid state electrochemical relations and literature data. The distribution of the electromotive potential, of Galvani potential, of concentration of electrons, e, and electron h...

  14. Leakage current behaviors of Al/ZrO2/Al and Al/YSZ/Al devices

    Science.gov (United States)

    Yeh, Tsung-Her; Lin, Ruei-De; Cherng, Bo-Ruei; Cherng, Jyh-Shiarn

    2015-01-01

    The leakage current behaviors of Al/ZrO2/Al and Al/yttria stabilized zirconia (YSZ)/Al devices are investigated for resistive random access memory (RRAM) applications. A silicon oxide layer (450 nm) is first formed on a Si wafer by thermal oxidation. Onto it an Al bottom electrode (270 nm), a ZrO2 or YSZ nano-film (75 nm), and an Al top electrode (270 nm) are sequentially deposited by sputtering. These RRAM devices exhibit ohmic behaviors in the low-field region, while Schottky and Poole-Frenkel emissions take over in the high-field regions. Both the Schottky and trap barrier levels are decreased when monoclinic ZrO2 is replaced by cubic YSZ in the metal/oxide/metal structure. This is attributed not only to the higher symmetry crystal structure and lower binding energy of YSZ, but also to the formation of more oxygen vacancies and their re-distribution associated with yttria doping.

  15. Growth and micro structural studies on Yittria Stabilized Zirconia (YSZ) and Strontium Titanate (STO) buffer layers

    Energy Technology Data Exchange (ETDEWEB)

    Srinivas, S.; Bhatnagar, A.K. [Univ. of Hyderabad (India); Pinto, R. [Solid State Electronics Group, Bombay (India)] [and others

    1994-12-31

    Microstructure of Yittria Stabilized Zirconia (YSZ) and Strontium Titanate (STO) of radio frequency magnetron sputtered buffer layers was studied at various sputtering conditions on Si<100>, Sapphire and LaAlO{sub 3} <100> substrates. The effect of substrate temperatures upto 800 C and sputtering gas pressures in the range of 50 mTorr. of growth conditions was studied. The buffer layers of YSZ and STO showed a strong tendency for columnar structure with variation growth conditions. The buffer layers of YSZ and STO showed orientation. The tendency for columnar growth was observed above 15 mTorr sputtering gas pressure and at high substrate temperatures. Post annealing of these films in oxygen atmosphere reduced the oxygen deficiency and strain generated during growth of the films. Strong c-axis oriented superconducting YBa{sub 2}Cu{sub 9}O{sub 7-x} (YBCO) thin films were obtained on these buffer layers using pulsed laser ablation technique. YBCO films deposited on multilayers of YSZ and STO were shown to have better superconducting properties.

  16. Development of graded Ni-YSZ composite coating on Alloy 690 by Pulsed Laser Deposition technique to reduce hazardous metallic nuclear waste inventory.

    Science.gov (United States)

    Sengupta, Pranesh; Rogalla, Detlef; Becker, Hans Werner; Dey, Gautam Kumar; Chakraborty, Sumit

    2011-08-15

    Alloy 690 based 'nuclear waste vitrification furnace' components degrade prematurely due to molten glass-alloy interactions at high temperatures and thereby increase the volume of metallic nuclear waste. In order to reduce the waste inventory, compositionally graded Ni-YSZ (Y(2)O(3) stabilized ZrO(2)) composite coating has been developed on Alloy 690 using Pulsed Laser Deposition technique. Five different thin-films starting with Ni80YSZ20 (Ni 80 wt%+YSZ 20 wt%), through Ni60YSZ40 (Ni 60 wt%+YSZ 40 wt%), Ni40YSZ60 (Ni 40 wt%+YSZ 60 wt%), Ni20YSZ80 (Ni 20 wt%+YSZ 80 wt%) and Ni0YSZ100 (Ni 0 wt%+YSZ 100 wt%), were deposited successively on Alloy 690 coupons. Detailed analyses of the thin-films identify them as homogeneous, uniform, pore free and crystalline in nature. A comparative study of coated and uncoated Alloy 690 coupons, exposed to sodium borosilicate melt at 1000°C for 1-6h suggests that the graded composite coating could substantially reduced the chemical interactions between Alloy 690 and borosilicate melt.

  17. Application of 8YSZ Nanopowder Synthesized by the Modified Solvothermal Process for Anode Supported Solid Oxide Fuel Cells.

    Science.gov (United States)

    Meepho, Malinee; Wattanasiriwech, Suthee; Angkavatana, Pavadee; Wattanasiriwech, Darunee

    2015-03-01

    Thin electrolyte yttria-stabilized zirconia (8YSZ) films were coated on the porous solid oxide fuel cell (SOFC) anode substrates for the use at an intermediate temperature range. Nano-8YSZ powder with a particle size of about 5 nm was synthesized using the modified solvothermal process. The electrolyte suspension was prepared by dispersion the synthesized 8YSZ nanopowder in ethanol, with PVB and 1,3-propanediol as a binder and a charging agent respectively. The 8YSZ suspension was subsequently deposited on the pre-sintered NiO-YSZ porous substrates by the electrophoretic deposition (EPD) technique. In order to obtain high quality electrolyte films, preparation process was optimized through two strategic approaches; (i) adjustment of suspension's rheological property and (ii) compatibility of anode-electrolyte sintering shrinkage. Rheological property of the suspension was improved with an addition of 1,3-propanediol. The zeta potential of this suspension was increased and reached the value of +24 mV so the well-dispersed slurry was finally obtained. The second approach was achieved by using a proper composite anode powders. Dense and uniform 8YSZ electrolyte films with a thickness of about 1 thickness successfully be formed on the NiO-YSZ porous substrates after co-sintering at 1400 °C for 2 h.

  18. The Role of Nanostructured Al2O3 Layer in Reduction of Hot Corrosion Products in Normal YSZ Layer

    Directory of Open Access Journals (Sweden)

    Mohammadreza Daroonparvar

    2013-01-01

    Full Text Available YVO4 crystals and monoclinic ZrO2 are known as hot corrosion products that can considerably reduce the lifetime of thermal barrier coatings during service. The hot corrosion resistance of two types of air plasma sprayed thermal barrier coating systems was investigated: an Inconel 738/NiCrAlY/YSZ (yttria-stabilized zirconia and an Inconel 738/NiCrAlY/YSZ/nano-Al2O3 as an outer layer. Hot corrosion test was accomplished on the outer surface of coatings in molten salts (45% Na2SO4 + 55% V2O5 at 1000°C for 52 hour. It was found that nanostructured alumina as outer layer of YSZ/nano-Al2O3 coating had significantly reduced the infiltration of molten salts into the YSZ layer and resulted in lower reaction of fused corrosive salts with YSZ, as the hot corrosion products had been substantially decreased in YSZ/nano-Al2O3 coating in comparison with normal YSZ coating after hot corrosion process.

  19. Environmental TEM study of the dynamic nanoscaled morphology of NiO/YSZ during reduction

    DEFF Research Database (Denmark)

    Simonsen, Søren Bredmose; Agersted, Karsten; Hansen, Karin Vels;

    2015-01-01

    the nanoscale morphological changes such as pore formation in NiO above 280°C and densification and collapse of the pore structures above 400°C. The accelerated Ni front in NiO illustrates the auto catalysis of the reaction. A rapid temperature ramping from room temperature to 780°C in hydrogen in 1 second...

  20. Facile one-step forming of NiO and yttrium-stabilized zirconia composite anodes with straight open pores for planar solid oxide fuel cell using phase-inversion tape casting method

    Science.gov (United States)

    Huang, Hua; Lin, Jie; Wang, Yunlong; Wang, Shaorong; Xia, Changrong; Chen, Chusheng

    2015-01-01

    The anode of NiO and yttria-stabilized zirconia (YSZ) with straight open pores is prepared by phase-inversion tape casting method. In the as-prepared green tape, its top and middle layers are derived from a slurry of NiO and YSZ, while the bottom layer from a slurry of graphite. The graphite layer is eliminated by calcination at elevated temperatures, leaving the finger-like porous layer exposed to the gas phase. A cell supported on the as-prepared anode substrate exhibits satisfactory electrochemical performances with a maximum power density of 780 mW cm-2 at 800 °C. The cell dose not show a convex-up curvature in I-V plots at high current density as often observed for most anode-supported cells, indicating the absence of concentration polarization which is in turn attributed to the open pore structure of the phase-inversion derived anode. The phase inversion tape casting technique explored in the present study involves almost the same equipments as and similar procedures to the conventional tape casting, and after further optimization it may become a simple and effective technique for mass production of anodes for SOFCs.

  1. Ensayos y pruebas de un calentador solar de agua operando por termosifón

    OpenAIRE

    Burbano Jaramillo, Juan Carlos; Restrepo Victoria, Alvaro Hernán; Sabogal F., Oscar Julián

    2007-01-01

    En este artículo se presentan los diferentes ensayos y pruebas hechos a un colector solar para calentamiento de agua de consumo doméstico, operando por termosifón. Los ensayos se hacen con base en la norma técnica colombiana NTC 4368. Se presentan además los resultados de las pruebas y las conclusiones a las mismas. In this paper, the different tests, made on a solar collector for heating of domestic use water operating by thermosifon is presented. The tests are made taking in account Colo...

  2. Semiconductor to Metal Transition Characteristics of VO2/NiO Epitaxial Heterostructures Integrated with Si(100)

    Science.gov (United States)

    Molaei, Roya

    The novel functionalities of Vanadium dioxide (VO2), such as, several orders of magnitude transition in resistivity and IR transmittance, provide the exciting opportunity for the development of next generation memory, sensor, and field-effect based devices. A critical issue in the development of practical devices based on metal oxides is the integration of high quality epitaxial oxide thin films with the existing silicon technology which is based on silicon (100) substrates. However, silicon is not suitable for epitaxial growth of oxides owing to its tendency to readily form an amorphous oxide layer or silicide at the film-substrate interface. The oxide films deposited directly on silicon exhibit poor crystallinity and are not suitable for device applications. To overcome this challenge, appropriate substrate templates must be developed for the growth of oxide thin films on silicon substrates. The primary objective of this dissertation was to develop an integration methodology of VO2 with Si (100) substrates so they could be used in "smart" sensor type of devices along with other multifunctional devices on the same silicon chip. This was achieved by using a NiO/c- YSZ template layer deposited in situ. It will be shown that if the deposition conditions are controlled properly. This approach was used to integrate VO 2 thin films with Si (100) substrates using pulsed laser deposition (PLD) technique. The deposition methodology of integrating VO2 thin films on silicon using various other template layers will also be discussed. Detailed epitaxial relationship of NiO/c-YSZ/Si(100) heterostructures as a template to growth of VO2 as well as were studied. We also were able to create a p-n junction within a single NiO epilayer through subsequent nanosecond laser annealing, as well as established a structure-property correlation in NiO/c-YSZ/Si(100) thin film epitaxial heterostructures with especial emphasis on the stoichiometry and crystallographic characteristics. NiO/c-YSZ

  3. Effect of composition on the polarization and ohmic resistances of LSM/YSZ composite cathodes in solid oxide fuel cell

    Indian Academy of Sciences (India)

    B SHRI PRAKASH; S SENTHIL KUMAR; S T ARUNA

    2017-06-01

    La0.8Sr0.2MnO$_3$−$\\delta$ (LSM)/8 mol% yttria-stabilized ZrO$_2$ (YSZ) (LSM/YSZ) composite cathodes with varying composition are studied for both polarization and ohmic resistance by electrochemical impedance spectroscopy. It was found that total resistance and polarization resistance are lowest for the composite with 60 wt% of LSM (LSM60/YSZ40). However, the ohmic resistance was highest for the same composition and amounted to 60% of the total resistance value. Compositional dependence of resistances has been explained based on the variations of the triple phase boundaries and width of the O$_2$−ion migration path with the composition of the electrode. Based on the observed area specific ohmic resistance values for the composite cathodes, it is proposed to verify the advantages of LSM/YSZ over LSM cathode in anode-supported solidoxide fuel cell with thin electrolyte.

  4. Application of in operando UV/Vis spectroscopy in lithium-sulfur batteries.

    Science.gov (United States)

    Patel, Manu U M; Dominko, Robert

    2014-08-01

    Application of UV/Vis spectroscopy for the qualitative and quantitative determination of differences in the mechanism of lithium-sulfur battery behavior is presented. With the help of catholytes prepared from chemically synthesized stoichiometric mixtures of lithium and sulfur, calibration curves for two different types of electrolyte can be constructed. First-order derivatives of UV/Vis spectra show five typical derivative peak positions in both electrolytes. In operando measurements show a smooth change in the UV/Vis spectra in the wavelength region between λ=650 and 400 nm. Derivatives are in agreement with derivative peak positions observed with catholytes. Recalculation of normalized reflections of UV/Vis spectra obtained in operando mode enable the formation of polysulfides and their concentrations to be followed. In such a way, it is possible to distinguish differences in the mechanism of polysulfide shuttling between two electrolytes and to correlate differences in capacity fading. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. A large format in operando wound cell for analysing the structural dynamics of lithium insertion materials

    Science.gov (United States)

    Brant, William R.; Roberts, Matthew; Gustafsson, Torbjörn; Biendicho, Jordi Jacas; Hull, Stephen; Ehrenberg, Helmut; Edström, Kristina; Schmid, Siegbert

    2016-12-01

    This paper presents a large wound cell for in operando neutron diffraction (ND) from which high quality diffraction patterns are collected every 15 min while maintaining conventional electrochemical performance. Under in operando data collection conditions the oxygen atomic displacement parameters (ADPs) and cell parameters were extracted for Li0.18Sr0.66Ti0.5Nb0.5O3. Analysis of diffraction data collected under in situ conditions revealed that the lithium is located on the (0.5 0.5 0) site, corresponding to the 3c Wyckoff position in the cubic perovskite unit cell, after the cell is discharged to 1 V. When the cell is discharged under potentiostatic conditions the quantity of lithium on this site increases, indicating a potential position where lithium becomes pinned in the thermodynamically stable phase. During this potentiostatic step the oxygen ADPs reduce significantly. On discharge, however, the oxygen ADPs were observed to increase gradually as more lithium is inserted into the structure. Finally, the rate of unit cell expansion changed by ∼44% once the lithium content approached ∼0.17 Li per formula unit. A link between lithium content and degree of mobility, disorder of the oxygen positions and changing rate of unit cell expansion at various stages during lithium insertion and extraction is thus presented.

  6. Correlating cycling history with structural evolution in commercial 26650 batteries using in operando neutron powder diffraction

    Science.gov (United States)

    Goonetilleke, Damian; Pramudita, James C.; Hagan, Mackenzie; Al Bahri, Othman K.; Pang, Wei Kong; Peterson, Vanessa K.; Groot, Jens; Berg, Helena; Sharma, Neeraj

    2017-03-01

    Ex situ and time-resolved in operando neutron powder diffraction (NPD) has been used to study the structural evolution of the graphite negative electrode and LiFePO4 positive electrode within ANR26650M1A commercial batteries from A123 Systems, in what to our knowledge is the first reported NPD study investigating a 26650-type battery. Batteries with different and accurately-known electrochemical and storage histories were studied, enabling the tell-tale signs of battery degradation to be elucidated using NPD. The ex-situ NPD data revealed that the intensity of the graphite/lithiated graphite (LixC6 or LiyC) reflections was affected by battery history, with lower lithiated graphite (LiC12) reflection intensities typically corresponding to more abused batteries. This indicates that the lithiation of graphite is less progressed in more abused batteries, and hence these batteries have lower capacities. In operando NPD allows the rate of structural evolution in the battery electrode materials to be correlated to the applied current. Interestingly, the electrodes exhibit different responses to the applied current that depend on the battery cycling history, with this particularly evident for the negative electrode. Therefore, this work illustrates how NPD can be used to correlate a battery history with electrode structure.

  7. Combined operando Raman/UV-Vis-NIR spectroscopy as a tool to study supported metal oxide catalysts at work

    NARCIS (Netherlands)

    Tinnemans, Stanislaus Josephus

    2006-01-01

    A novel set-up has been developed in which two complementary spectroscopic techniques, namely operando Raman and UV-Vis-NIR spectroscopy, are combined. With this set-up it is possible to characterize catalytic materials under reaction conditions (high temperature, normal pressure) and in this way on

  8. Polarization Induced Changes in LSM Thin Film Electrode Composition Observed by In Operando Raman Spectroscopy and TOF-SIMS

    DEFF Research Database (Denmark)

    McIntyre, Melissa D.; Traulsen, Marie Lund; Norrman, Kion

    2015-01-01

    Polarization induced changes in LSM electrode composition were investigated by utilizing in operando Raman spectroscopy and post mortem TOF-SIMS depth profiling. Experiments were conducted on cells with 160 nm thick (La0.85Sr0.15)0.9MnO3±δ thin film electrodes in 10% O2 at 700 °C under various...

  9. Combined operando Raman/UV-Vis-NIR spectroscopy as a tool to study supported metal oxide catalysts at work

    NARCIS (Netherlands)

    Tinnemans, Stanislaus Josephus

    2006-01-01

    A novel set-up has been developed in which two complementary spectroscopic techniques, namely operando Raman and UV-Vis-NIR spectroscopy, are combined. With this set-up it is possible to characterize catalytic materials under reaction conditions (high temperature, normal pressure) and in this way on

  10. Fabrication of bilayered YSZ/SDC electrolyte film by electrophoretic deposition for reduced-temperature operating anode-supported SOFC

    Science.gov (United States)

    Matsuda, Motohide; Hosomi, Takushi; Murata, Kenji; Fukui, Takehisa; Miyake, Michihiro

    Bilayered Y 2O 3-stabilized ZrO 2 (YSZ)/Sm 2O 3-doped CeO 2 (SDC) electrolyte films were successfully fabricated on porous NiO-YSZ composite substrates by electrophoretic deposition (EPD) based on electrophoretic filtration followed by co-firing with the substrates. In EPD, positively charged YSZ and SDC powders were deposited directly on the substrates, layer by layer from ethanol-based suspensions. Delamination between YSZ and SDC films was avoided by reducing the SDC films' thickness to ca. 1 μm. A single cell was constructed on the bilayered electrolyte films composed of ca. 4 μm-thick YSZ and ca. 1 μm-thick SDC films. As a cathode in the cell, La 0.6Sr 0.4Co 0.2Fe 0.8O 3- x (LSCF) was used. Maximum output power densities greater than 0.6 W cm -2 were obtained at 700 °C for the bilayered YSZ/SDC electrolyte cells thus constructed.

  11. Fabrication of bilayered YSZ/SDC electrolyte film by electrophoretic deposition for reduced-temperature operating anode-supported SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, Motohide; Hosomi, Takushi; Miyake, Michihiro [Graduate School of Environmental Science, Okayama University, 3-1-1 Tsushima-Naka, Okayama 700-8530 (Japan); Murata, Kenji; Fukui, Takehisa [Hosowaka Powder Technology Research Institute, 1-9 Shoudai, Tajika, Hirakata, Osaka 573-1132 (Japan)

    2007-02-25

    Bilayered Y{sub 2}O{sub 3}-stabilized ZrO{sub 2} (YSZ)/Sm{sub 2}O{sub 3}-doped CeO{sub 2} (SDC) electrolyte films were successfully fabricated on porous NiO-YSZ composite substrates by electrophoretic deposition (EPD) based on electrophoretic filtration followed by co-firing with the substrates. In EPD, positively charged YSZ and SDC powders were deposited directly on the substrates, layer by layer from ethanol-based suspensions. Delamination between YSZ and SDC films was avoided by reducing the SDC films' thickness to ca. 1 {mu}m. A single cell was constructed on the bilayered electrolyte films composed of ca. 4 {mu}m-thick YSZ and ca. 1 {mu}m-thick SDC films. As a cathode in the cell, La{sub 0.6}Sr{sub 0.4}Co{sub 0.2}Fe{sub 0.8}O{sub 3-x} (LSCF) was used. Maximum output power densities greater than 0.6 W cm{sup -2} were obtained at 700 C for the bilayered YSZ/SDC electrolyte cells thus constructed. (author)

  12. Aqueous metal–organic solutions for YSZ thin film inkjet deposition

    DEFF Research Database (Denmark)

    Gadea, Christophe; Hanniet, Q.; Lesch, A.

    2017-01-01

    Inkjet printing of 8% Y2O3-stabilized ZrO2 (YSZ) thin films is achieved by designing a novel water-based reactive ink for Drop-on-Demand (DoD) inkjet printing. The ink formulation is based on a novel chemical strategy that consists of a combination of metal oxide precursors (zirconium alkoxide...... and yttrium salt), water and a nucleophilic agent, i.e. n-methyldiethanolamine (MDEA). This chemistry leads to metal–organic complexes with long term ink stability and high precision printability. Ink rheology and chemical reactivity are analyzed and controlled in terms of metal–organic interactions...... in the solutions. Thin dense nanocrystalline YSZ films below 150 nm are obtained by low temperature calcination treatments (400–500 °C), making the deposition suitable for a large variety of substrates, including silicon, glass and metals. Thin films and printed patterns achieve full densification with no lateral...

  13. Electronic excitation and relaxation processes of oxygen vacancies in YSZ and their involvement in photoluminescence

    Energy Technology Data Exchange (ETDEWEB)

    Morimoto, Takaaki; Kuroda, Yasuhiro [Waseda University, Department of Electrical Engineering and Bioscience, Shinjuku, Tokyo (Japan); Ohki, Yoshimichi [Waseda University, Department of Electrical Engineering and Bioscience, Shinjuku, Tokyo (Japan); Waseda University, Research Institute for Materials Science and Technology, Shinjuku, Tokyo (Japan)

    2016-09-15

    Yttria-stabilized zirconia (YSZ) consists of zirconia and yttria and oxygen vacancies appear in accordance with the ratio of yttria. The oxygen vacancy would sometimes give annoyance, but it would be beneficial on other occasions, depending on its applications. Photoluminescence (PL) due to oxygen vacancies induced by photons with energies around 5.5 eV exhibits two decay time constants. As a possible reason for this, an oxygen vacancy changes its charging state from neutral to positive monovalent by losing an electron when YSZ is irradiated by ultraviolet photons. The PL decays either in a ms range or in a ns range, depending on whether the oxygen vacancies are neutral or positive monovalent. (orig.)

  14. Ni/YSZ microstructure optimization for long-term stability of solid oxide electrolysis cells

    DEFF Research Database (Denmark)

    Hauch, Anne; Brodersen, Karen; Karas, Filip;

    2014-01-01

    In the last decade there has been a renewed and increased interest in electrolysis using solid oxide cells (SOC). So far the vast majority of results reported on long-term durability of solid oxide electrolysis cells (SOEC) have been obtained using SOC produced and optimized for fuel cell operation......; i.e. solid oxide fuel cells (SOFC). However, previous long-term tests have shown that the stability behavior of the Ni/yttria-stabilized-zirconia (Ni/YSZ) fuel electrode may fall out quite differently depending on whether the cell is operated in fuel cell or electrolysis mode at otherwise similar...... test conditions. Initial work has shown significant microstructural changes of the Ni/YSZ electrode close to the electrolyte interface after long-term steam electrolysis test at -1 A/cm2 at 800 C. The results indicate that it will be advantageous to optimize the electrode structure with the aim...

  15. Crystallization and oxygen loading in pulsed laser deposited YSZ-films

    Energy Technology Data Exchange (ETDEWEB)

    Ernst, Benedikt; Liese, Tobias; Hoffmann, Sarah; Krebs, Hans-Ulrich [Institut fuer Materialphysik, University of Goettingen, Friedrich-Hund-Platz 1, 37077 Goettingen (Germany)

    2011-07-01

    Yttria-stabilized zirconium dioxide (YSZ) as an oxygen ion conductor is widely used in technical applications, for example as solid oxide fuel cells. Thus, it is important studying the film stability at higher temperatures. In this contribution, amorphous YSZ films prepared by Pulsed Laser Deposition (PLD) at room temperature and annealed in argon/vacuum or oxygen atmosphere are presented. In a first thermal treatment in high vacuum up to temperatures of 800 C a loss of oxygen and crystallization of the film is achieved. Further heating in oxygen atmosphere leads to a reversible reloading of oxygen in the film. At this, changing the heating time and temperature enables to obtain different levels of oxygen in the samples. The weight change during outgasing and reloading was measured by thermal gravimetric analysis (TGA). The structure of different oxygen states and dynamics of crystallization was characterized by in-situ X-ray diffraction (XRD) and ellipsometry.

  16. Three-phase-boundary dynamics at the Ni/ScYSZ interface

    DEFF Research Database (Denmark)

    Schmidt, Michael Stenbæk; Hansen, Karin Vels; Norrman, Kion;

    2009-01-01

    Chronoamperometry using a three-electrode cell configuration was undertaken with a nickel point-electrode acting as the working electrode on a polished ScYSZ electrolyte in a hydrogen atmosphere at 750–850 °C. High anodic overpotentials resulted in the occurrence of distinct sawtooth oscillation...... of the current oscillations. A mechanism accounting for the observed phenomena and possible implications for solid oxide fuel cell operation are presented...

  17. Sintering study of NiO-YSZ composite obtained by coprecipitation route; Estudo de sinterabilidade do composito de NiO-YSZ obtido pela rota de coprecipitacao

    Energy Technology Data Exchange (ETDEWEB)

    Yoshito, W.K.; Resitivo, T.A.G.; Ussui, V.; Lazar, D.R.R.; Paschoal, J.O.A., E-mail: wyoshito@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (CCTM/IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Ciencia e Tecnologia de Materiais

    2009-07-01

    NiO-YSZ composite is a widely used anode material for solid oxide fuel cell. The main purpose of the present work was the evaluation of the appropriate conditions of ceramic processing, by sintering behavior study of NiO-YSZ pressed powders, synthesized by hydroxide coprecipitation route. Using the empirical rate equation developed by Makipirtti-Meng, it was analyzed shrinkage rate in the temperature ranges of 900-1400 deg C as function of time. The powders were characterized by X-ray diffraction, scanning electron microscopy, gas adsorption, laser diffraction and helium picnometry. The microstructural characterization of the samples was evaluated by X-ray diffraction, scanning electron microscopy and relative density by the Archimedes method. It was found that activation energy value is 48,3 kJ.mol{sup -1} in the temperature range of 900-950 deg C and 604,83 kJ.mol{sup -1} for 1000-1200 deg C. These values correspond to the change that occurs in the microstructure during the heat treatment process. The sintering process was evaluated by the dilatometry date treatment. (author)

  18. YSZ-Reinforced Alumina Multi-Channel Capillary Membranes for Micro-Filtration

    Directory of Open Access Journals (Sweden)

    Bo Wang

    2015-12-01

    Full Text Available The combined phase-inversion and sintering method not only produces ceramic hollow fibre membranes with much lower fabrication costs than conventional methods, but these membranes can also be designed to have greatly reduced transport resistances for filtration processes. The bottleneck of this technique is the weak mechanical property of the fibres, due to the small dimensions and the brittle nature of the ceramic materials. In this study, yttrium stabilised zirconia (YSZ reinforced alumina seven-channel capillary microfiltration membranes were prepared with a pore size of ~230 nm and their mechanical property and permeation characteristics were studied. It is found that the addition of YSZ can effectively enhance the mechanical property of the membrane and also increase pure water permeation flux. The Al2O3-YSZ seven-channel capillary membranes could reach a fracture load of 23.4 N and a bending extension of 0.54 mm when being tested with a 6 cm span, to meet the requirements for most industrial microfiltration applications.

  19. YSZ-Reinforced Alumina Multi-Channel Capillary Membranes for Micro-Filtration.

    Science.gov (United States)

    Wang, Bo; Lee, Melanie; Li, Kang

    2015-12-30

    The combined phase-inversion and sintering method not only produces ceramic hollow fibre membranes with much lower fabrication costs than conventional methods, but these membranes can also be designed to have greatly reduced transport resistances for filtration processes. The bottleneck of this technique is the weak mechanical property of the fibres, due to the small dimensions and the brittle nature of the ceramic materials. In this study, yttrium stabilised zirconia (YSZ) reinforced alumina seven-channel capillary microfiltration membranes were prepared with a pore size of ~230 nm and their mechanical property and permeation characteristics were studied. It is found that the addition of YSZ can effectively enhance the mechanical property of the membrane and also increase pure water permeation flux. The Al₂O₃-YSZ seven-channel capillary membranes could reach a fracture load of 23.4 N and a bending extension of 0.54 mm when being tested with a 6 cm span, to meet the requirements for most industrial microfiltration applications.

  20. Revisiting the Birth of 7YSZ Thermal Barrier Coatings: Steve Stecura

    Science.gov (United States)

    Smialek, James L.; Miller, Robert A.

    2017-01-01

    Thermal barrier coatings are widely used in all turbine engines, typically using a 7 wt% Y2O3-ZrO2 formulation. Extensive research and development over many decades have refined the processing and structure of these coatings for increased durability and reliability. New compositions demonstrate some unique advantages and are gaining in application. However, the "7YSZ" formulation predominates and is still in widespread use. This special composition has been universally found to produce nanoscale precipitates of metastable t' tetragonal phase, giving rise to a unique toughening mechanism via ferro-elastic switching under stress. This note recalls the original study that identified superior properties of 6 to 8 wt% YSZ plasma sprayed thermal barrier coatings, published in 1978. The impact of this discovery, arguably, continues in some form to this day. At one point, 7YSZ thermal barrier coatings were used in every new aircraft and ground power turbine engine produced worldwide. It is a tribute to its inventor, Dr. Stephan J. Stecura, NASA retiree.

  1. Electrocatalysts the basis of nickel and iron supported YSZ and GDC for SOFC with direct reform

    Energy Technology Data Exchange (ETDEWEB)

    Fiuza, R.P.; Silva, M.A.; Boaventura, J.S. [Inst. de Quimica, Salvador (Brazil). Dept. de Fisico Quimica

    2009-07-01

    This study discussed the use of nickel-iron (Ni-Fe) supported yttria-stabilized zircon (YSZ) and GDC for solid oxide fuel cells (SOFCs). The Pechina method was used to prepare the electrocatalysts, which were then calcined at 900 degrees C. Ethanol steam reforming at a molar ethanol-water ratio of 1:3 at temperatures ranging between 300 and 900 degrees C as well as at a fixed temperature of 650 degrees C. The catalysts were monitored continuously. Results of the study showed that ethanol conversion and selectivity of the Ni YSZ samples was 80 per cent, while the GDC sample was 30 per cent at temperatures of 900 degrees C. Ethanol conversion rates for the Ni-Fe YSZ sample was 95 per cent. The Ni-Fe sample also showed improved resistance to carbon formation with less than 10 per cent carbon deposition. It was concluded that the improved resistance to carbon deposits can be attributed to lower iron catalyst activity and the lower acid character of the iron electrocatalyst.

  2. Varying the exchange interaction between NiO nanoparticles

    DEFF Research Database (Denmark)

    Bahl, Christian Robert Haffenden; Mørup, Steen

    2006-01-01

    We demonstrate that exchange interactions between antiferromagnetic nanoparticles of 57Fe-doped NiO can be varied by simple macroscopic treatments. Mössbauer spectroscopy studies of the superparamagnetic relaxation behaviour show that grinding or suspension in water of nanoparticles of NiO can...... significantly reduce interparticle interactions. Slow drying of aqueous suspensions of NiO nanoparticles did not lead to enhanced interparticle interactions. This is opposite to the behaviour of α-Fe2O3 (hematite) nanoparticles....

  3. Varying the exchange interaction between NiO nanoparticles

    DEFF Research Database (Denmark)

    Bahl, Christian Robert Haffenden; Mørup, Steen

    2006-01-01

    We demonstrate that exchange interactions between antiferromagnetic nanoparticles of 57Fe-doped NiO can be varied by simple macroscopic treatments. Mössbauer spectroscopy studies of the superparamagnetic relaxation behaviour show that grinding or suspension in water of nanoparticles of NiO can...... significantly reduce interparticle interactions. Slow drying of aqueous suspensions of NiO nanoparticles did not lead to enhanced interparticle interactions. This is opposite to the behaviour of α-Fe2O3 (hematite) nanoparticles....

  4. The cytotoxicity of NiO nanoparticle with borate capping.

    Science.gov (United States)

    Liu, Zunjing; Wang, Yongjing; Pan, Danmei; Chen, Zhi; Pan, Xiaohong; Wang, Yonghao; Lin, Zhang

    2011-11-01

    The impact of surface capping on cytotoxicity of NiO nanoparticle was investigated with Escherichia coil (E.coli) in this work. The NiO nanoparticle and NiO nanoparticle capped by borate (denoted as NiO-borate) were synthesized by hydrothermal method. The average size of both nanoparticles is about 4.0 nm. The plate experiments demonstrated that NiO-borate nanoparticles show lower cytotoxicity than NiO nanopaticles. Further spectrophotometric analysis revealed that the concentration of both extracellular and intercellular Ni2+ in NiO-borate system were lower than that of uncapped one. Intracellular ICP-AES analysis also showed the concentration of Ni element was higher than Ni2+, suggesting the NiO nanoparticles might penetrate into the cellular interior. Comprehensive AFM, SEM and TEM observation illustrated both NiO-borate and NiO nanoparticles lead to the collapse of cellular body, the convex on the cell wall and the damage of cell wall ultimately. In summary, the surface capping with borate on NiO nanopaticles will suppress the release of the Ni2+ ions and impede the contact between the NiO nanoparticle and cell wall, which ultimately decreased the cytotoxicity of NiO nanoparticles.

  5. Microstructural degradation of Ni-YSZ anodes for solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Thyden, K.

    2008-03-15

    Ni-YSZ cermets have been used as anode materials in SOFCs for more than 20 years. Despite this fact, the major cause of degradation within the Ni-YSZ anode, namely Ni sintering / coarsening, is still not fully understood. Even if microstructural studies of anodes in tested cells are of technological relevance, it is difficult to identify the effect from isolated parameters such as temperature, fuel gas composition and polarization. Model studies of high temperature aged Ni-YSZ cermets are generally performed in atmospheres containing relatively low concentrations of H2O. In this work, the microstructural degradation in both electrochemically longterm tested cells and high-temperature aged model materials are studied. Since Ni particle sintering / coarsening is attributed to be the major cause of anode degradation, this subject attains the primary focus. A large part of the work is focused on improving microstructural techniques and shows that the application of low acceleration voltages (<= 1 kV) in a FE-SEM makes it possible to obtain two useful types of contrast between the phases in Ni-YSZ composites. By changing between the ordinary lateral SE detector and the inlens detector, using similar microscope settings, two very different sample characteristics are probed: 1) The difference in secondary emission coefficient, delta, between the percolating and non-percolating Ni is maximized in the low-voltage range due to a high delta for the former and the suppression of delta by a positive charge for the latter. This difference yields a contrast between the two phases which is picked up by an inlens secondary electron detector. 2) The difference in backscatter coefficient, eta, between Ni and YSZ is shown to increase with decreasing voltage. The contrast is illustrated in images collected by the normal secondary detector since parts of the secondary signals are generated by backscattered electrons. High temperature aging experiments of model Ni-YSZ anode cermets show

  6. YSZ包覆NiO阳极的SOFC发电性能%Electrical performance of SOFC with anode of YSZ coating NiO

    Institute of Scientific and Technical Information of China (English)

    由宏新; 刘国东; 丁信伟; 阿布里提·阿布都拉

    2007-01-01

    在溶解Y2O3的盐酸溶液中,加入ZrOCl2·8H2O和NiO,采用NH3·H2O-NH4HCO3为缓冲溶液,以共沉淀法制备了YSZ包覆NiO的NiO-YSZ阳极材料.用X射线衍射仪和透射电镜,分析了所制取材料的物相和粒子粒径大小.分别以YSZ包覆的NiO和商品NiO/YSZ为阳极,LSM为阴极,制作YSZ电解质支撑的板状固体氧化物燃料电池,进行发电性能比较.结果表明,以YSZ包覆的NiO为阳极的电池,功率密度高、极限电流密度大.扫描电镜观察表明,YSZ包覆的NiO制作的阳极表面形成了网状结构,使阳极三相界面和孔隙率提高,从而提高了电池性能.

  7. Real-time observations of lithium battery reactions-operando neutron diffraction analysis during practical operation.

    Science.gov (United States)

    Taminato, Sou; Yonemura, Masao; Shiotani, Shinya; Kamiyama, Takashi; Torii, Shuki; Nagao, Miki; Ishikawa, Yoshihisa; Mori, Kazuhiro; Fukunaga, Toshiharu; Onodera, Yohei; Naka, Takahiro; Morishima, Makoto; Ukyo, Yoshio; Adipranoto, Dyah Sulistyanintyas; Arai, Hajime; Uchimoto, Yoshiharu; Ogumi, Zempachi; Suzuki, Kota; Hirayama, Masaaki; Kanno, Ryoji

    2016-06-30

    Among the energy storage devices for applications in electric vehicles and stationary uses, lithium batteries typically deliver high performance. However, there is still a missing link between the engineering developments for large-scale batteries and the fundamental science of each battery component. Elucidating reaction mechanisms under practical operation is crucial for future battery technology. Here, we report an operando diffraction technique that uses high-intensity neutrons to detect reactions in non-equilibrium states driven by high-current operation in commercial 18650 cells. The experimental system comprising a time-of-flight diffractometer with automated Rietveld analysis was developed to collect and analyse diffraction data produced by sequential charge and discharge processes. Furthermore, observations under high current drain revealed inhomogeneous reactions, a structural relaxation after discharge, and a shift in the lithium concentration ranges with cycling in the electrode matrix. The technique provides valuable information required for the development of advanced batteries.

  8. Real-time observations of lithium battery reactions—operando neutron diffraction analysis during practical operation

    Science.gov (United States)

    Taminato, Sou; Yonemura, Masao; Shiotani, Shinya; Kamiyama, Takashi; Torii, Shuki; Nagao, Miki; Ishikawa, Yoshihisa; Mori, Kazuhiro; Fukunaga, Toshiharu; Onodera, Yohei; Naka, Takahiro; Morishima, Makoto; Ukyo, Yoshio; Adipranoto, Dyah Sulistyanintyas; Arai, Hajime; Uchimoto, Yoshiharu; Ogumi, Zempachi; Suzuki, Kota; Hirayama, Masaaki; Kanno, Ryoji

    2016-06-01

    Among the energy storage devices for applications in electric vehicles and stationary uses, lithium batteries typically deliver high performance. However, there is still a missing link between the engineering developments for large-scale batteries and the fundamental science of each battery component. Elucidating reaction mechanisms under practical operation is crucial for future battery technology. Here, we report an operando diffraction technique that uses high-intensity neutrons to detect reactions in non-equilibrium states driven by high-current operation in commercial 18650 cells. The experimental system comprising a time-of-flight diffractometer with automated Rietveld analysis was developed to collect and analyse diffraction data produced by sequential charge and discharge processes. Furthermore, observations under high current drain revealed inhomogeneous reactions, a structural relaxation after discharge, and a shift in the lithium concentration ranges with cycling in the electrode matrix. The technique provides valuable information required for the development of advanced batteries.

  9. Water management in a planar air-breathing fuel cell array using operando neutron imaging

    Science.gov (United States)

    Coz, E.; Théry, J.; Boillat, P.; Faucheux, V.; Alincant, D.; Capron, P.; Gébel, G.

    2016-11-01

    Operando Neutron imaging is used for the investigation of a planar air-breathing array comprising multiple cells in series. The fuel cell demonstrates a stable power density level of 150 mW/cm2. Water distribution and quantification is carried out at different operating points. Drying at high current density is observed and correlated to self-heating and natural convection. Working in dead-end mode, water accumulation at lower current density is largely observed on the anode side. However, flooding mechanisms are found to begin with water condensation on the cathode side, leading to back-diffusion and anodic flooding. Specific in-plane and through-plane water distribution is observed and linked to the planar array design.

  10. Operando PXD of Vanadium-Based Nanomaterials as Cathodes for Mg-ion Batteries

    DEFF Research Database (Denmark)

    Christensen, Christian Kolle; Sørensen, Daniel Risskov; Mathiesen, Jette

    Exchanging the active specie, Li+ in Li-ion batteries by multivalent, abundant and cheap cations, such as Mg2+, are projected to boost the energy density and lower the cost per kilo-watt-hour significantly, making the Mg-ion battery technology a promising candidate for one of the battery...... with the host lattice of the electrodes and hampers facile ion transport. Therefore, development of novel electrode materials for effective Mg-ion storage is a vital step for the realization of this battery technology.3 In this study, we have synthesized series of vanadium oxides with varying chemical...... composition and varying nanotopologies, e.g. multiwalledVOx-nanotubes. The mechanism for Mg-intercalation and deintercalation is studied by operando synchrotron powder X-ray diffraction measured during battery operation. These results Mg-intercalation in the multiwalled VOx -nanotubes occurs within the space...

  11. Observation and Quantification of Nanoscale Processes in Lithium Batteries by Operando Electrochemical (S)TEM

    Energy Technology Data Exchange (ETDEWEB)

    Mehdi, Beata L.; Qian, Jiangfeng; Nasybulin, Eduard; Park, Chiwoo; Welch, David A.; Faller, Roland; Mehta, Hardeep S.; Henderson, Wesley A.; Xu, Wu; Wang, Chong M.; Evans, James E.; Liu, Jun; Zhang, Jiguang; Mueller, Karl T.; Browning, Nigel D.

    2015-03-11

    An operando electrochemical stage for the transmission electron microscope has been configured to form a “Li battery” that is used to quantify the electrochemical processes that occur at the anode during charge/discharge cycling. Of particular importance for these observations is the identification of an image contrast reversal that originates from solid Li being less dense than the surrounding liquid electrolyte and electrode surface. This contrast allows Li to be identified from Li containing compounds that make up the solid-electrolyte interphase (SEI) layer. By correlating images showing the sequence of Li electrodeposition and the evolution of the SEI layer with simultaneously acquired and calibrated cyclic voltammograms (CV), electrodeposition and electrolyte breakdown processes can be quantified directly on the nanoscale. This approach opens up intriguing new possibilities to rapidly visualize and test the electrochemical performance of a wide range of electrode/electrolyte combinations for next generation battery systems.

  12. Real-time observations of lithium battery reactions—operando neutron diffraction analysis during practical operation

    Science.gov (United States)

    Taminato, Sou; Yonemura, Masao; Shiotani, Shinya; Kamiyama, Takashi; Torii, Shuki; Nagao, Miki; Ishikawa, Yoshihisa; Mori, Kazuhiro; Fukunaga, Toshiharu; Onodera, Yohei; Naka, Takahiro; Morishima, Makoto; Ukyo, Yoshio; Adipranoto, Dyah Sulistyanintyas; Arai, Hajime; Uchimoto, Yoshiharu; Ogumi, Zempachi; Suzuki, Kota; Hirayama, Masaaki; Kanno, Ryoji

    2016-01-01

    Among the energy storage devices for applications in electric vehicles and stationary uses, lithium batteries typically deliver high performance. However, there is still a missing link between the engineering developments for large-scale batteries and the fundamental science of each battery component. Elucidating reaction mechanisms under practical operation is crucial for future battery technology. Here, we report an operando diffraction technique that uses high-intensity neutrons to detect reactions in non-equilibrium states driven by high-current operation in commercial 18650 cells. The experimental system comprising a time-of-flight diffractometer with automated Rietveld analysis was developed to collect and analyse diffraction data produced by sequential charge and discharge processes. Furthermore, observations under high current drain revealed inhomogeneous reactions, a structural relaxation after discharge, and a shift in the lithium concentration ranges with cycling in the electrode matrix. The technique provides valuable information required for the development of advanced batteries. PMID:27357605

  13. Structural dynamics and activity of nanocatalysts inside fuel cells by in operando atomic pair distribution studies

    Science.gov (United States)

    Petkov, Valeri; Prasai, Binay; Shan, Shiyao; Ren, Yang; Wu, Jinfang; Cronk, Hannah; Luo, Jin; Zhong, Chuan-Jian

    2016-05-01

    Here we present the results from a study aimed at clarifying the relationship between the atomic structure and activity of nanocatalysts for chemical reactions driving fuel cells, such as the oxygen reduction reaction (ORR). In particular, using in operando high-energy X-ray diffraction (HE-XRD) we tracked the evolution of the atomic structure and activity of noble metal-transition metal (NM-TM) nanocatalysts for ORR as they function at the cathode of a fully operational proton exchange membrane fuel cell (PEMFC). Experimental HE-XRD data were analysed in terms of atomic pair distribution functions (PDFs) and compared to the current output of the PEMFC, which was also recorded during the experiments. The comparison revealed that under actual operating conditions, NM-TM nanocatalysts can undergo structural changes that differ significantly in both length-scale and dynamics and so can suffer losses in their ORR activity that differ significantly in both character and magnitude. Therefore we argue that strategies for reducing ORR activity losses should implement steps for achieving control not only over the length but also over the time-scale of the structural changes of NM-TM NPs that indeed occur during PEMFC operation. Moreover, we demonstrate how such a control can be achieved and thereby the performance of PEMFCs improved considerably. Last but not least, we argue that the unique capabilities of in operando HE-XRD coupled to atomic PDF analysis to characterize active nanocatalysts inside operating fuel cells both in a time-resolved manner and with atomic level resolution, i.e. in 4D, can serve well the ongoing search for nanocatalysts that deliver more with less platinum.Here we present the results from a study aimed at clarifying the relationship between the atomic structure and activity of nanocatalysts for chemical reactions driving fuel cells, such as the oxygen reduction reaction (ORR). In particular, using in operando high-energy X-ray diffraction (HE

  14. Operando formation of an ultra-low friction boundary film from synthetic magnesium silicon hydroxide additive

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Qiuying; Rudenko, Pavlo; Miller, Dean J.; Wen, Jianguo; Berman, Diana; Zhang, Yuepeng; Arey, Bruce; Zhu, Zihua; Erdemir, Ali

    2017-06-01

    The paper reports the operando and self-healing formation of DLC films at sliding contact surfaces by the addition of synthetic magnesium silicon hydroxide (MSH) nanoparticles to base oil. The formation of such films leads to a reduction of the coefficient of friction by nearly an order of magnitude and substantially reduces wear losses. The ultralow friction layer characterized by transmission electron microscope (TEM), electron energy loss spectroscopy (EELS), and Raman spectroscopy consists of amorphous DLC containing SiOx that forms in a continuous and self-repairing manner during operation. This environmentally benign and simple approach offers promise for significant advances in lubrication and reduced energy losses in engines and other mechanical systems.

  15. In operando PXRD study P2-NaxTMO2 cycled in a sodium ion battery

    DEFF Research Database (Denmark)

    Birgisson, Steinar; Shen, Yanbin; Christiansen, Troels Lindahl;

    Sodium ion batteries (SIB) are being considered as a cheaper and more environmentally friendly alternative to lithium ion batteries (LIB). Application of SIB is especially important in large scale electricity storage from renewable energy sources [1]. A mayor hindrance of the development of SIB...... for practical applications is that so far there are no known electrode materials with sufficiently good rate and cycling capability. Studying structural changes of electrode materials while the battery is being charged and discharged is important to gain a deeper understanding of processes affecting...... the electrode materials. This understanding can be used to optimize battery performance and understand decay mechanisms, which in turn will facilitate the development of electrode materials fit for practical application in SIB. Our research group has developed an in operando battery cell capable of following...

  16. Structural dynamics and activity of nanocatalysts inside fuel cells by in operando atomic pair distribution studies.

    Science.gov (United States)

    Petkov, Valeri; Prasai, Binay; Shan, Shiyao; Ren, Yang; Wu, Jinfang; Cronk, Hannah; Luo, Jin; Zhong, Chuan-Jian

    2016-05-19

    Here we present the results from a study aimed at clarifying the relationship between the atomic structure and activity of nanocatalysts for chemical reactions driving fuel cells, such as the oxygen reduction reaction (ORR). In particular, using in operando high-energy X-ray diffraction (HE-XRD) we tracked the evolution of the atomic structure and activity of noble metal-transition metal (NM-TM) nanocatalysts for ORR as they function at the cathode of a fully operational proton exchange membrane fuel cell (PEMFC). Experimental HE-XRD data were analysed in terms of atomic pair distribution functions (PDFs) and compared to the current output of the PEMFC, which was also recorded during the experiments. The comparison revealed that under actual operating conditions, NM-TM nanocatalysts can undergo structural changes that differ significantly in both length-scale and dynamics and so can suffer losses in their ORR activity that differ significantly in both character and magnitude. Therefore we argue that strategies for reducing ORR activity losses should implement steps for achieving control not only over the length but also over the time-scale of the structural changes of NM-TM NPs that indeed occur during PEMFC operation. Moreover, we demonstrate how such a control can be achieved and thereby the performance of PEMFCs improved considerably. Last but not least, we argue that the unique capabilities of in operando HE-XRD coupled to atomic PDF analysis to characterize active nanocatalysts inside operating fuel cells both in a time-resolved manner and with atomic level resolution, i.e. in 4D, can serve well the ongoing search for nanocatalysts that deliver more with less platinum.

  17. Synthesis of LSM films deposited by dip-coating on YSZ substrate; Sintese de filmes de LSM depositados por dip-coating em substratos de YSZ

    Energy Technology Data Exchange (ETDEWEB)

    Conceicao, Leandro da; Souza, Mariana M.V.M., E-mail: mmattos@eq.ufrj.b [Universidade Federal do Rio de Janeiro (EQ/UFRJ), RJ (Brazil). Escola de Quimica; Ribeiro, Nielson F.P. [Coordenacao dos Programas de Pos-graduacao de Engenharia (PEQ/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Quimica. Nucleo de Catalise

    2010-07-01

    The dip-coating process was used to deposit films of La{sub 0.7}Sr{sub 0.}3MnO{sub 3} (LSM) used as cathode in solid oxide fuel cells (SOFC). In this study we evaluated the relationship between the deposition parameters such as speed of withdrawal and number of deposited layers of LSM film on a substrate of 8% YSZ commercial, and structural properties, such as thickness and formation of cracks. The structure and morphology of the films were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). With parameters set the film had good adhesion to the substrate with a thickness around 10 {mu}m, showing possible adherence problems when more than one layer is deposited on the substrate. (author)

  18. Phase Stability of Ce-Modified La2Zr2O7 Coatings and Chemical Compatibility with YSZ

    Science.gov (United States)

    Wu, Qiong; Ji, Xiaojuan; Peng, Haoran; Ren, Xianjing; Yu, Yueguang

    2016-04-01

    Ce-modified La2Zr2O7 powders, i.e., La2Zr2O7 (LZ), La2(Zr0.7Ce0.3)2O7 (LZ7C3), and La2(Zr0.3Ce0.7)2O7 (LZ3C7), were used to produce thermal barrier coatings by atmospheric plasma spray process. The chemical compatibility of the CeO2-doped La2Zr2O7 with the traditional YSZ was investigated in LZ-YSZ powder mixtures and LZ-YSZ bilayer coatings by x-ray diffraction and scanning electron microscope. The powder mixtures and coatings were aged at 1200 and 1300 °C for 100 h. The results showed that LZ and LZ7C3 presented single pyrochlore structure after the heat treatments at both 1200 and 1300 °C. For LZ3C7, however, fluorite structure was observed at 1300 °C, indicating a poor phase stability of LZ3C7 at the elevated temperature. The results further showed that La2(Zr0.3Ce0.7)2O7 reacted with YSZ in the bilayer ceramic coatings due to the diffusion of cerium, zirconium, and yttrium. While for La2Zr2O7(LZ) and La2(Zr0.7Ce0.3)2O7, a better chemical compatibility with YSZ was shown.

  19. Operando characterization of batteries using x-ray absorption spectroscopy: advances at the beamline XAFS at synchrotron Elettra

    Science.gov (United States)

    Aquilanti, Giuliana; Giorgetti, Marco; Dominko, Robert; Stievano, Lorenzo; Arčon, Iztok; Novello, Nicola; Olivi, Luca

    2017-02-01

    X-ray absorption spectroscopy is a synchrotron radiation based technique that is able to provide information on both local structure and electronic properties in a chemically selective manner. It can be used to characterize the dynamic processes that govern the electrochemical energy storage in batteries, and to shed light on the redox chemistry and changes in structure during galvanostatic cycling to design cathode materials with improved properties. Operando XAS studies have been performed at beamline XAFS at Elettra on different systems. For Li-ion batteries, a multiedge approach revealed the role of the different cathode components during the charge and discharge of the battery. In addition, Li-S batteries for automotive applications were studied. Operando sulfur K-edge XANES and EXAFS analysis was used to characterize the redox chemistry of sulfur, and to relate the electrochemical mechanism to its local structure.

  20. Biogas Upgrading Using SOEC with a Ni-ScYSZ Electrode

    DEFF Research Database (Denmark)

    Ebbesen, Sune Dalgaard; Bøgild Hansen, John; Mogensen, Mogens Bjerg

    2013-01-01

    Biogas consists mainly of CH4, CO2 and small amounts of H2S. The value of biogas will increase significantly if it is upgraded to pipeline quality by converting CO2 and H2O in the biogas to CO and H2 using a Solid Oxide Electrolysis Cell (SOEC) followed by methanation. The Ni-ScYSZ-cermet electrode...... is, however, active for steam reforming of CH4, but sulphur traces in the biogas reduce the steam reforming activity. It is proven that sulphur stops steam reforming activity whereas the electrochemistry is only affected to a limited degree, showing that up-grading of biogas using SOEC with Ni...

  1. Methane Steam Reforming over an Ni-YSZ Solid Oxide Fuel Cell Anode in Stack Configuration

    DEFF Research Database (Denmark)

    Mogensen, David; Grunwaldt, Jan-Dierk; Hendriksen, Peter Vang;

    2014-01-01

    The kinetics of catalytic steam reforming of methane over an Ni-YSZ anode of a solid oxide fuel cell (SOFC) have been investigated with the cell placed in a stack configuration. In order to decrease the degree of conversion, a single cell stack with reduced area was used. Measurements were...... performed in the temperature range 600-800 degrees C and the partial pressures of all reactants and products were varied. The obtained rates could be well fitted with a power law expression (r proportional to P-CH4(0.7)). A simple model is presented which is capable of predicting the methane conversion...

  2. Effects of strong cathodic polarization of the Ni-YSZ interface

    DEFF Research Database (Denmark)

    Hansen, Karin Vels; Chen, Ming; Jacobsen, Torben

    2016-01-01

    resulted. Impedance spectroscopy shows initial decrease but later increase in the series resistance and polarization resistance during the 140-160 h of polarization, and significant inductive behavior. An intermetallic Ni-Zr phase that formed during polarization was preserved when the polarization was kept...... during cooling, and was identified post-mortem by transmission electron microscopy as Ni7Zr2. ZrO2 nanoparticles were formed on the Ni-gas surface next to the Ni-YSZ-gas triple phase boundary. Explanations of the observed features are offered based on electron microscopy and impedance spectroscopy....

  3. Effect of anodic polarization on the free-floating parts at Pt/YSZ catalyst electrode

    Energy Technology Data Exchange (ETDEWEB)

    Toghan, Arafat, E-mail: arafat.toghan@yahoo.com [Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstrasse 3, D-91058 Erlangen (Germany); Chemistry Department, Faculty of Science, South Valley University, 83523 Qena (Egypt); Institut für Physikalische Chemie und Elektrochemie, Leibniz-Universität Hannover, Callinstrasse 3-3a, D-30167 Hannover (Germany); Imbihl, R. [Institut für Physikalische Chemie und Elektrochemie, Leibniz-Universität Hannover, Callinstrasse 3-3a, D-30167 Hannover (Germany)

    2015-09-30

    Photoemission electron microscopy (PEEM) was used as spatially resolving method to explore the effect of electrochemical pumping with a positive voltage to porous platinum electrodes interfaced as working electrode to yttrium stabilized zirconia (YSZ). The experiments were conducted under UHV conditions (p ≈ 10{sup −9} mbar). In PEEM a uniform rapid darkening of the Pt surface was observed during anodic polarization followed by the appearance of bright spots on a dark background. The bright spots observed in PEEM images are due to zirconia reduction around electrically isolated Pt islands.

  4. Electrical conductivity of Ni–YSZ composites: Variants and redox cycling

    DEFF Research Database (Denmark)

    Pihlatie, Mikko; Kaiser, Andreas; Mogensen, Mogens Bjerg

    2012-01-01

    Short-term changes in the electrical conductivity of different Ni–YSZ composites (cermets) were measured by an in-situ 4-point DC technique. The isothermal reduction was carried out in dry, humidified or wet hydrogen at temperatures from 600 to 850°C. The cermets reduced at 600°C showed a stable...... the conductivity loss data. The MSC analysis yielded apparent activation energies for Ni sintering within the composite of 375kJ/mol when heated in dry H2 and 440kJ/mol when under wet H2....

  5. Effect of Aging on the Electrochemical Performance of LSM-YSZ Cathodes

    DEFF Research Database (Denmark)

    Baqué, L. C.; Jørgensen, Peter Stanley; Zhang, Wei

    2015-01-01

    Investigations of degradation mechanisms of solid oxide fuel cells are crucial for achieving a widespread commercialization of the technology. In this work, electrochemical impedance spectroscopy (EIS) was applied for studying the aging effect on LSM-YSZ cathodes exposed to humidified air at 900°C...... resistance shows no clear tendency with aging time, while the ionic conductivity decreases up to ∼79%. Accordingly, the electrochemically active thickness contracts from 60–135 μm to 45–60 μm. The changes observed in the cathode transport and electrochemical properties are mostly explained by the evolution...

  6. The Effect of Humidity and Oxygen Partial Pressure on LSM–YSZ Cathode

    DEFF Research Database (Denmark)

    Knöfel, Christina; Chen, Ming; Mogensen, Mogens Bjerg

    2011-01-01

    Two series of anode supported solid oxide fuel cells (SOFC) were prepared, one with a composite cathode layer of lanthanum strontium manganite (LSM) and yttria stabilized zirconia (YSZ) on top and the other further has a LSM current collector layer on top. The fuel cells were heat treated at 1...... of manganese concentration and strontium enrichment on the surface of the materials. Formation of monoclinic zirconia and zirconate phases was also observed. These results give a closer insight into possible degradation mechanisms of SOFC composite cathode materials in dependence of humidity and oxygen partial...

  7. Homogenous Crack-Free Large Size YBCO/YSZ/Sapphire Films for Application

    Science.gov (United States)

    Almog, B.; Azoulay, M.; Deutscher, G.

    2006-09-01

    YBa2Cu3O7-δ (YBCO) films grown on Sapphire are highly suitable for applications. The production of large size (2-3″) homogeneous, thick (d ⩾ 600nm) films of high quality is of major importance. We report the growth of such films using a buffer layer of Yttrium-stabilized ZrO2(YSZ). The films are highly homogeneous and show excellent mechanical properties. They exhibit no sign of cracking even after many thermal cycles. Their critical thickness exceeds 1000nm. However, because of the large lattice mismatch there is a decrease in the electric properties(increases Rs, decreases jc).

  8. Electrical conductivity of Ni–YSZ composites: Degradation due to Ni particle growth

    DEFF Research Database (Denmark)

    Pihlatie, Mikko; Kaiser, Andreas; Mogensen, Mogens Bjerg;

    2011-01-01

    The short-term changes in the electrical conductivity of Ni–YSZ composites (cermets) suitable for use in Solid Oxide Fuel Cells (SOFC) were measured by an in-situ 4-point DC technique. The isothermal reduction was carried out in dry, humidified or wet hydrogen at temperatures from 600 to 1000°C...... of steam did have an accelerating effect on the conductivity loss. Scanning Electron Microscopy of cermets reduced in different conditions showed increasing particle size and loss of metal-to-metal percolation in the samples reduced at higher temperatures. The short-term changes in conductivity were...

  9. A HREM study of the atomic structure and the growth mechanism of the YBa2Cu3O7/YSZ interface

    NARCIS (Netherlands)

    Wen, J.G.; Traeholt, C.; Zandbergen, H.W.; Joosse, K.; Reuvekamp, E.M.C.M.; Rogalla, H.

    1993-01-01

    The interface between yttria-stabilized zirconia (YSZ) substrate and YBa2Cu3O7 (YBCO) film was studied by high-resolution electron microscopy. In all specimens we have observed an intermediate layer of BaZrO3 located between the substrate YSZ and YBCO. The BaZrO3 layer is composed of almost equally

  10. In situ time-of-flight neutron imaging of NiO-YSZ anode support reduction under influence of stress

    DEFF Research Database (Denmark)

    Makowska, Malgorzata Grazyna; Strobl, Markus; Lauridsen, Erik M.

    2016-01-01

    This article reports on in situ macroscopic scale imaging of NiO-YSZ (YSZ is yttria-stabilized zirconia) reduction under applied stress - a phase transition taking place in solid oxide electrochemical cells in a reducing atmosphere of a hydrogen/nitrogen mixture and at operation temperatures of u...

  11. Identification of Dimeric Methylalumina Surface Species during Atomic Layer Deposition Using Operando Surface-Enhanced Raman Spectroscopy.

    Science.gov (United States)

    Hackler, Ryan A; McAnally, Michael O; Schatz, George C; Stair, Peter C; Van Duyne, Richard P

    2017-02-15

    Operando surface-enhanced Raman spectroscopy (SERS) was used to successfully identify hitherto unknown dimeric methylalumina surface species during atomic layer deposition (ALD) on a silver surface. Vibrational modes associated with the bridging moieties of both trimethylaluminum (TMA) and dimethylaluminum chloride (DMACl) surface species were found during ALD. The appropriate monomer vibrational modes were found to be absent as a result of the selective nature of SERS. Density functional theory (DFT) calculations were also performed to locate and identify the expected vibrational modes. An operando localized surface plasmon resonance (LSPR) spectrometer was utilized to account for changes in SER signal as a function of the number of ALD cycles. DMACl surface species were unable to be measured after multiple ALD cycles as a result of a loss in SERS enhancement and shift in LSPR. This work highlights how operando optical spectroscopy by SERS and LSPR scattering are useful for probing the identity and structure of the surface species involved in ALD and, ultimately, catalytic reactions on these support materials.

  12. 3D Microstructure Effects in Ni-YSZ Anodes: Influence of TPB Lengths on the Electrochemical Performance

    Directory of Open Access Journals (Sweden)

    Omar M. Pecho

    2015-10-01

    Full Text Available 3D microstructure-performance relationships in Ni-YSZ anodes for electrolyte-supported cells are investigated in terms of the correlation between the triple phase boundary (TPB length and polarization resistance (Rpol. Three different Ni-YSZ anodes of varying microstructure are subjected to eight reduction-oxidation (redox cycles at 950 °C. In general the TPB lengths correlate with anode performance. However, the quantitative results also show that there is no simplistic relationship between TPB and Rpol. The degradation mechanism strongly depends on the initial microstructure. Finer microstructures exhibit lower degradation rates of TPB and Rpol. In fine microstructures, TPB loss is found to be due to Ni coarsening, while in coarse microstructures reduction of active TPB results mainly from loss of YSZ percolation. The latter is attributed to weak bottlenecks associated with lower sintering activity of the coarse YSZ. The coarse anode suffers from complete loss of YSZ connectivity and associated drop of TPBactive by 93%. Surprisingly, this severe microstructure degradation did not lead to electrochemical failure. Mechanistic scenarios are discussed for different anode microstructures. These scenarios are based on a model for coupled charge transfer and transport, which allows using TPB and effective properties as input. The mechanistic scenarios describe the microstructure influence on current distributions, which explains the observed complex relationship between TPB lengths and anode performances. The observed loss of YSZ percolation in the coarse anode is not detrimental because the electrochemical activity is concentrated in a narrow active layer. The anode performance can be predicted reliably if the volume-averaged properties (TPBactive, effective ionic conductivity are corrected for the so-called short-range effect, which is particularly important in cases with a narrow active layer.

  13. A non-destructive method for determination of thermal conductivity of YSZ coatings deposited on Si substrates

    Energy Technology Data Exchange (ETDEWEB)

    Amaya, C. [Thin Films Group, Department of Physics, Universidad del Valle, Cali (Colombia); Research Group in Development of Materials and Products, CDT-ASTIN SENA, Cali (Colombia); Caicedo, J.C., E-mail: jcaicedoangulo1@gmail.com [Thin Films Group, Department of Physics, Universidad del Valle, Cali (Colombia); Yanez-Limon, J.M. [Cinvestav-Unidad Queretaro, Dept. of Materials Science and Engineering, Queretaro (Mexico); Vargas, R.A. [Group Phase Transitions in Non-metallic Systems, Universidad del Valle, Cali (Colombia); Zambrano, G.; Gomez, M.E. [Thin Films Group, Department of Physics, Universidad del Valle, Cali (Colombia); Prieto, P. [Excellence Center for Novel Materials, Universidad del Valle, Cali (Colombia)

    2012-10-15

    Thermal diffusivity ({alpha}) of YSZ coatings was determined by the phase lag method of the photo-acoustic signal for rear and frontal illuminations using a two-beam photo-acoustic cell. XRD results show the presence of a tetragonal phase with (101) and (112) orientations, and FTIR spectra exhibit the 2{sub Eu} and F{sub 1u} modes as two broad bands in the frequency at 453 cm{sup -1}, 468 cm{sup -1}, corresponding to the tetragonal phase of ZrO{sub 2}. Thermal diffusivity was measured in the Si/YSZ system and also on the Si (100) substrate from which a simple two-layer system model. Via specific heat measurements at constant pressure (C{sub p}) using the (DSC) technique, and mass density ({rho}) calculations using Archimedes and Aleksandrov's methods for both in-bulk and film YSZ samples, thermal conductivity ({kappa}) was obtained. The results were: {alpha} = (0.0021 {+-} 0.0002) and (0.0023 {+-} 0.0002) cm{sup 2} s{sup -1}, {rho} = (4.7725 {+-} 0.005) Multiplication-Sign 10{sup 3} and (5.883 {+-} 0.005) Multiplication-Sign 10{sup 3} kg m{sup -3}, C{sub p} = (427 {+-} 14) J kg{sup -1} K{sup -1}, and {kappa} = (0.43 {+-} 0.06) and (0.57 {+-} 0.06) W m{sup -1} K{sup -1} for in-bulk and film YSZ samples, respectively. -- Highlights: Black-Right-Pointing-Pointer Anon-destructive method for determination of thermal conductivity. Black-Right-Pointing-Pointer Novel relationship between density, porosity and thermal diffusivity in 8YSZ coating. Black-Right-Pointing-Pointer Thermal diffusivity of 8YSZ coating analyzed by the phase lag method of the photo-acoustic signal.

  14. On the Densification Behavior of (0.2, 0.5, and 1 Wt Pct) CNT-YSZ Ceramic Composites Processed via Spark Plasma Sintering

    Science.gov (United States)

    Karanam, Abhinav; Bichler, Lukas; Fong, Randy

    2015-08-01

    Yttria-Stabilized Zirconia (YSZ) is a promising thermal insulating ceramic for high temperature applications due to its stability and chemical inertness. As was demonstrated with other technical ceramics ( e.g., Alumina), addition of Single-Wall Carbon Nanotubes (CNTs) to a ceramic matrix may significantly enhance its mechanical properties. In this work, 8 mol pct YSZ with 0.2, 0.5, and 1 wt pct CNT composites were fabricated via the spark plasma sintering process. The densification, Vicker's microhardness, specific gravity, and microstructure evolution of the composites were investigated. The results suggest that the addition of CNTs to YSZ hindered densification and grain growth during SPS processing leading to inhomogeneous grain size distribution. However, the CNTs had a profound impact on the hardness of the composite ceramics, with an increase from 697 HV (YSZ) to 1195 HV (1 wt pctCNT-YSZ).

  15. Relation between shape of Ni-particles and Ni migration in Ni-YSZ electrodes – a hypothesis

    DEFF Research Database (Denmark)

    Mogensen, Mogens Bjerg; Hauch, Anne; Sun, Xiufu

    2016-01-01

    pressure (pH2O) gradient as previously observed [1], but in the present cases Ni seems to migrate up the pH2O gradient. However, it is also observed that there is a preceding phase in this Ni-YSZ electrode degradation, namely that the Ni-particles closest to the YSZ electrolyte loose contact to each other....... This means that the active three phase boundary (TPB) moves away from the electrolyte and causes a significant increase in the ohmic resistance as is also observed in electrochemical impedance spectra....

  16. Cidade, gastronomia e património

    OpenAIRE

    Encarnação, José d'

    2012-01-01

    Em todos os países, a gastronomia (ou a culinária) tradicional constitui cada vez mais um património, que importa valorizar e divulgar, não só para fomentar a identidade local e regional perante a avassaladora globalização, mas também para despertar apetite no turista. E se, oficialmente, os governos legislam já no sentido dessa promoção, certo é que são localmente os municípios que maior dinâmica manifestam no sentido dessa consciencialização. Aproveita-se o ensejo para dar conta de como já ...

  17. Spin Seebeck effect through antiferromagnetic NiO

    Science.gov (United States)

    Prakash, Arati; Brangham, Jack; Yang, Fengyuan; Heremans, Joseph P.

    2016-07-01

    We report temperature-dependent spin Seebeck measurements on Pt/YIG bilayers and Pt/NiO/YIG trilayers, where YIG (yttrium iron garnet, Y3F e5O12 ) is an insulating ferrimagnet and NiO is an antiferromagnet at low temperatures. The thickness of the NiO layer is varied from 0 to 10 nm. In the Pt/YIG bilayers, the temperature gradient applied to the YIG stimulates dynamic spin injection into the Pt, which generates an inverse spin Hall voltage in the Pt. The presence of a NiO layer dampens the spin injection exponentially with a decay length of 2 ± 0.6 nm at 180 K. The decay length increases with temperature and shows a maximum of 5.5 ± 0.8 nm at 360 K. The temperature dependence of the amplitude of the spin Seebeck signal without NiO shows a broad maximum of 6.5 ± 0.5 μV/K at 20 K. In the presence of NiO, the maximum shifts sharply to higher temperatures, likely correlated to the increase in decay length. This implies that NiO is most transparent to magnon propagation near the paramagnet-antiferromagnet transition. We do not see the enhancement in spin current driven into Pt reported in other papers when 1-2 nm NiO layers are sandwiched between Pt and YIG.

  18. Pressure gap and electrode artefacts in the electrochemically induced oxygen spillover on Pt/YSZ electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Toghan, Arafat; Roesken, Liz; Imbihl, Ronald [Institut fuer Physikalische Chemie und Elektrochemie, Leibniz-Universitaet Hannover, Callinstr. 3 - 3a, D-30167 Hannover (Germany); Haevecker, Michael; Knop-Gericke, Axel [Fritz-Haber-Institut, Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin (Germany)

    2011-07-01

    Mechanistically, the electrochemical promotion of catalytic reactions (EPOC) on Pt/YSZ (yttrium stabilized zirconia) catalysts has been shown to be due to the spillover of oxygen from the solid electrolyte onto the Pt surface. This spillover has been studied on Pt/YSZ catalysts with photoemission electron microscope (PEEM) and with a differentially pumped x-ray photoelectron spectrometer (XPS) allowing to conduct in situ studies up to 1 mbar. PEEM revealed that upon electrochemical pumping not only the expected darkening of the Pt electrodes can be observed which is due to spillover oxygen but that also bright spots develop. These bright spots were attributed to metallic zirconium formed as electrically disconnected parts of the Pt electrode assume a negative potential thus causing a local reduction of zirconia. With XPS the main goal was to study whether a second special spillover species develops upon electrochemical pumping at high pressure which is different from chemisorbed oxygen. This special spillover species has been postulated by Vayenas et al. and was supposedly responsible for the non-Faradaic nature of EPOC. Up to now even at p=0.2 mbar only chemisorbed oxygen was detected.

  19. Effect of specific absorbed power on microwave sintering of 3YSZ ceramics

    Science.gov (United States)

    Bykov, Yu V.; Egorov, S. V.; Eremeev, A. G.; Plotnikov, I. V.; Rybakov, K. I.; Sorokin, A. A.; Kholoptsev, V. V.

    2017-07-01

    Samples of 3 % yttria-stabilized zirconia (3YSZ) ceramics have been sintered to near full density with no appreciable grain growth using an ultra-rapid microwave sintering process. The sintering experiments were carried out on a 24 GHz / 6 kW gyrotron system for microwave processing of materials with automatic process control. By varying the properties of the thermal insulation surrounding the samples it was possible to vary the microwave power required for heating. The final relative density of 3YSZ ceramic samples microwave heated at a rate of 50 °C/min to a temperature of 1400 °C without isothermal hold varied from 91.6 % when the specific absorbed microwave power was 4 W/cm3 to 99.4 % when the specific absorbed microwave power was 90 W/cm3. The specific absorbed power is therefore demonstrated to be the key parameter determining the achievable density in ultra-rapid field-assisted sintering processes.

  20. LSM-YSZ cathode with infiltrated cobalt oxide and cerium oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ohno, R.; Murata, K.; Hirano, A.; Takeda, Y.; Yamamoto, O. [Department of Chemistry, Mie University, Tsu (Japan); Yamahara, K. [Mitsubihsi Chemical Corporation, Shiba, Minato-ku, Tokyo (Japan); Imanishi, N.

    2009-06-15

    To improve the La{sub 0.8}Sr{sub 0.2}MnO{sub 3} (LSM) -8 mol-%Y{sub 2}O{sub 3}-ZrO{sub 2} (YSZ) cathode performance of intermediate temperature solid oxide fuel cells (SOFC), Co{sub 3}O{sub 4} and CeO{sub 2} nanoparticles were infiltrated into the cathode. Co-infiltration of these oxide particles drastically enhanced the cell performance between 800 and 600 C. The infiltrated CeO{sub 2} suppressed the aggregation of nanoparticle Co{sub 3}O{sub 4}, resulting in the high catalytic activity of the nanoparticle Co{sub 3}O{sub 4} for oxygen reduction at intermediate temperatures. The anode-supported SOFC with Co{sub 3}O{sub 4} and CeO{sub 2} co-infiltrated LSM-YSZ cathode at 700 C showed the high specific power density of 0.58 W cm{sup -2} at 0.7 V. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  1. Thermal Cycling Behavior of Quasi-Columnar YSZ Coatings Deposited by PS-PVD

    Science.gov (United States)

    Yang, Jiasheng; Zhao, Huayu; Zhong, Xinghua; Shao, Fang; Liu, Chenguang; Zhuang, Yin; Ni, Jinxing; Tao, Shunyan

    2017-01-01

    Columnar-structured thermal barrier coatings, owing to their high strain tolerance, are expected for their potential possibilities to substantially extend turbine lives and improve engine efficiencies. In this paper, plasma spray-physical vapor deposition (PS-PVD) process was used to deposit yttria partially stabilized zirconia (YSZ) coatings with quasi-columnar structures. Thermal cyclic tests on burner rigs and thermal shock tests by heating and water-quenching method were involved to evaluate the thermal cycling and thermal shock behaviors of such kind of structured thermal barrier coatings (TBCs). Evolution of the microstructures, phase composition, residual stresses and failure behaviors of quasi-columnar YSZ coatings before and after the thermal tests was investigated. The quasi-columnar coating obtained had an average life of around 623 cycles when the spallation area reached about 10% of the total coating surface during burner rig tests with the coating surface temperature of 1250 °C. Failure of the coating is mainly due to the break and pull-out of center columnar segments.

  2. Deposition of nanostructured YSZ coating from spray-dried particles with no heat treatment

    Science.gov (United States)

    Zhao, Yan; Gao, Yang

    2015-08-01

    Ytrria stabilized zirconia (YSZ) nanoparticle agglomerates were fabricated by a spray dry method and were directly sprayed using atmospheric plasma spraying (APS) with a current of 300 A and 500 A. A commercially supplied nanostructured YSZ powder (sintered) was also sprayed under the same conditions for comparison. A scanning electron microscope (SEM), an optical microscope (OM) and X-ray diffraction (XRD) were utilized to characterize the feedstock powder and coatings. Weibull plots were used to analyze the performance of the nanostructured coatings. The lower 300 A operating current resulted in a higher portion of nanostructure retention at the expense of coating quality. An approximate 10% increase in porosity and a noticeable decrease in grain size (∼104 nm) were obtained by spraying non-heat treated agglomerates with a 500 A current. The thermal conductivity (400-600 °C) was evaluated using the one-dimensional, steady state Fourier's law of heat conduction. Next, lower thermal conductivity (∼1.3 W m-1 K-1 at 600 °C) was identified in coatings engineered at 500 A from agglomerated powder with no heat treatment.

  3. NiO nanosheet assembles for supercapacitor electrode materials

    Institute of Scientific and Technical Information of China (English)

    Huanhao Xiao; Shunyu Yao; Hongda Liu; Fengyu Qu; Xu Zhang n; Xiang Wu n

    2016-01-01

    In this paper, large scale hierarchically assembled NiO nanosheets have been favorably fabricated through a facile hydrothermal route. The as-prepared NiO nanosheet assembles were characterized in detail by various analytical techniques. The results showed these nanosheets present the thickness of about 30 nm and the surface area is 116.9 m2 g ? 1. These NiO nanosheet assembles were used as the working electrode materials in electrochemical tests, which demonstrated a specific capacitance value of 81.67 F g ? 1 at the current density of 0.5 A g ? 1 and excellent long cycle-life stability with 78.5% of its discharge specific capacitance retention after 3000 cycles at the current density of 0.5 A g?1, revealing the as-synthesized NiO nanosheet assembles might be a promising electrode material for supercapacitor applications.

  4. Directional waverider buoy in Indian waters - Experiences of NIO

    Digital Repository Service at National Institute of Oceanography (India)

    AshokKumar, K.; Diwan, S.G.

    , receiving/ recording unit, NIO's experience in mooring, deployment and retrieval operations etc. The paper also highlights various operational problems during the data collection programme. Suggestions and conclusions pertaining to operation, maintenance etc...

  5. Measurements of local chemistry and structure in Ni(O)-YSZ composites during reduction using energy-filtered environmental TEM

    DEFF Research Database (Denmark)

    Jeangros, Quentin; Hansen, Thomas Willum; Wagner, Jakob Birkedal;

    2014-01-01

    Energy-filtered transmission electron microscopy images are acquired during the reduction of a NiO-YSZ composite in H-2 up to 600 degrees C. Temperature-resolved quantitative information about both chemistry and structure is extracted with nm spatial resolution from the data, paving the way...

  6. The effect of potassium addition to Pt supported on YSZ on steam reforming of mixtures of methane and ethane

    NARCIS (Netherlands)

    Graf, P.O.; Mojet, Barbara; Lefferts, Leonardus

    2009-01-01

    The influence of potassium addition on Pt supported on yttrium-stabilized zirconia (YSZ) was studied with FT-IR CO adsorption and CO-FT-IR-TPD, in order to understand the effect of potassium on the performance of the catalyst in reforming of mixtures of methane and ethane. Potassium modification of

  7. A dual layer Ni/Ni-YSZ hollow fibre for micro-tubular SOFC anode support with a current collector

    Energy Technology Data Exchange (ETDEWEB)

    Kanawka, Krzysztof; Othman, Mohd Hafiz Dzarfan; Wu, Zhentao; Droushiotis, Nicolas; Kelsall, Geoff; Li, Kang [Department of Chemical Engineering and Chemical Technology, Imperial College London (United Kingdom)

    2011-01-15

    A co-extrusion technique was employed to fabricate a dual layer NiO/NiO-YSZ hollow fibre precursor which was then co-sintered at 1400C and reduced at 700C to form, respectively, a meshed porous inner Ni current collector and outer Ni-YSZ anode layers for SOFC applications. Achieved morphology consisted of short finger-like voids originating from the inner bore of the hollow fibre, and a sponge-like structure filling most of the Ni-YSZ anode layer, which is considered to be suitable macrostructure for anode SOFC system. The electrical conductivity of the meshed porous inner Ni layer was measured to be 77.5 x 10{sup 5} S m{sup -1}. This result is significantly higher than previous reported results on single layer Ni-YSZ hollow fibres, which besides performing a catalyst function for the oxidation reaction also act as a current collector. These results highlight the advantages of this dual-layer hollow fibre design especially in developing a new and highly efficient way in current collection for micro-tubular SOFC. (author)

  8. Visualizing the structural evolution of LSM/xYSZ composite cathodes for SOFC by in-situ neutron diffraction.

    Science.gov (United States)

    Chen, Yan; Yang, Ling; Ren, Fei; An, Ke

    2014-06-05

    Thermal stability of composite cathodes for solid oxide fuel cells, the mixtures of (La0.8Sr0.2)0.95MnO(3-δ) (LSM) and (Y2O3)(x)(ZrO2)(1-x) (xYSZ, x = 3, 6, 8 and 10), is determined using in-situ neutron diffraction. Thanks to the most advanced high flux neutron source, our work highlights the visualization of the phase evolutions in heterogeneous material systems at high temperatures, along with the analysis of the diffusion activities of transition metal ions that reveal the reaction mechanism and kinetics. It is found that the tetragonal-to-cubic phase transition in YSZ at T > 900°C leads to a heterogeneous redistribution of Mn ions. The subsequent reaction of LSM and YSZ occurring at T > 1100°C is revealed as a three-stage kinetic process, yielding La2Zr2O7, SrZrO3 and MnO. The diffusion activities of Y, Mn and La ions in the heterogeneous systems at elevated temperatures are derived by the structural analysis, and the three-stage reaction of YSZ and LSM is found strongly correlated to ions' behaviors as functions of temperature.

  9. Effects of trace elements at the Ni/ScYSZ interface in a model solid oxide fuel cell anode

    DEFF Research Database (Denmark)

    Schmidt, Michael Stenbæk; Hansen, Karin Vels; Norrman, Kion

    2008-01-01

    Two ScYSZ electrolytes with different impurity levels were evaluated by electrochemical impedance spectroscopy using a nickel point electrode setup. The nickel electrodes showed lower electrode polarization resistances on the pure electrolyte than on the impure electrolyte. Time-of-flight seconda...

  10. Microstructural Characterization of Ni/YSZ Electrodes in a Solid Oxide Electrolysis Stack Tested for 9000 Hours

    DEFF Research Database (Denmark)

    Trini, Martina; Jørgensen, Peter Stanley; Hauch, Anne

    2017-01-01

    The effects of long-term operation in electrolysis mode on the microstructure of Ni/YSZ electrodes were investigated. The electrode structures were investigated in “as reduced” state and after 9000 h of operation in a 25 cell stack. Microstructural data were obtained by scanning electron microscopy...

  11. Preparation of SmBiO3 buffer layer on YSZ substrate by an improved chemical solution deposition route

    Science.gov (United States)

    Zhu, Xiaolei; Pu, Minghua; Zhao, Yong

    2016-12-01

    A quick route for chemical solution deposition (CSD) has been developed to prepare SmBiO3 (SBO) layers on yttria stabilized zirconia (YSZ) substrates rapidly by using of solid state decomposition (SSD) technique. The proper conditions for volatilization of lactic acid, which as solvent in precursor coated layer, and SBO growth are 115°C for 30 min and 794°C for 60 min in flowing Ar gas. The coated layers are amorphous structure of mixture oxides and quasi-crystal structure of SBO before and after growth, respectively. The total time by this quick CSD route for organic solvent volatilization, salts decomposed and layer growth is not up to 2 h, which are much less than that needed for traditional CSD of over 10 h. SBO layer is directly epitaxial growth on YSZ substrate without any lattice rotation. SBO layer prepared by this quick route as well as that by traditional route are suitable for the growth of YBCO. The superconducting transition temperature and critical current density of the coated YBCO layer on SBO/YSZ obtained by this quick route are up to 90 K and 1.66 MA/cm2. These results may be the usable reference for continuous preparation of SBO buffer layer on IBAD-YSZ/Ni-based alloy tapes.

  12. Fabrication Of YSZ Thin Film By Electrochemical Deposition Method And The Effect Of The Pulsed Electrical Fields For Morphology Control

    Directory of Open Access Journals (Sweden)

    Fujita T.

    2015-06-01

    Full Text Available In this study, surface morphology control ions in a precursor solution and patterning the YSZ film has been carried out during deposition of thin film from a precursor solution by applying the electrical field for deposition and the pulsed electrical field. The precursor solution was mixed them of ZrO(NO34, Y(NO33-6H2O into deionized water, and then was controlled nearly pH3 by adding NH3(aq. The thin film was deposited on the glass substrate of the minus electrode side by applying the electrical field of 3.0 V for 20 min. In addition, another pulsed voltage was applied to the electrical field along the perdicular direction to the film deposition direction. After annealing samples at 773 K for 6 h in air, the film was crystallized and obtained YSZ film. In the limited condition, the linear patterns of YSZ films due to the frequency of the applied electrical field were observed. It is expected that ions in a precursor solution are controlled by applying the pulsed voltage and the YSZ film is patterned on the substrate.

  13. The effect of potassium addition to Pt supported on YSZ on steam reforming of mixtures of methane and ethane

    NARCIS (Netherlands)

    Graf, Patrick O.; Mojet, Barbara L.; Lefferts, Leon

    2009-01-01

    The influence of potassium addition on Pt supported on yttrium-stabilized zirconia (YSZ) was studied with FT-IR CO adsorption and CO-FT-IR-TPD, in order to understand the effect of potassium on the performance of the catalyst in reforming of mixtures of methane and ethane. Potassium modification of

  14. Influence of in-flight particle state diagnostics on properties of plasma sprayed YSZ-CeO2 nanocomposite coatings

    Directory of Open Access Journals (Sweden)

    S. Mantry

    2014-07-01

    Full Text Available This article describes the influence of controlling in-flight hot particle characteristics on properties of plasma sprayed nanostructured yttria stabilized zirconia (YSZ coatings. This article depicts dependence of adhesion strength of as-sprayed nanostructured YSZ coatings on particle temperature, velocity and size of the splat prior to impact on the metallic substrate. Particle temperature measurement is based on two-color pyrometry and particle velocities are measured from the length of the particle traces during known exposure times. The microstructure and adhesion strength of as-sprayed nano-YSZ coatings were studied. Field emission scanning electron microscopy results revealed that morphology of coating exhibits bimodal microstructure consisting of nano-zones reinforced in the matrix of fully melted particles. The coating adhesion strength is noticed to be greatly affected by the melting state of agglomerates. Maximum adhesion strength of 42.39 MPa has been experimentally found out by selecting optimum levels of particle temperature and velocity. The enhanced bond strength of nano-YSZ coating may be attributed to higher interfacial toughness due to cracks being interrupted by adherent nano-zones.

  15. Improved Thermally Grown Oxide Scale in Air Plasma Sprayed NiCrAlY/Nano-YSZ Coatings

    Directory of Open Access Journals (Sweden)

    Mohammadreza Daroonparvar

    2013-01-01

    Full Text Available Oxidation has been considered as one of the principal disruptive factors in thermal barrier coating systems during service. So, oxidation behavior of thermal barrier coating (TBC systems with nanostructured and microstructured YSZ coatings was investigated at 1000∘C for 24 h, 48 h, and 120 h. Air plasma sprayed nano-YSZ coating exhibited a trimodal structure. Microstructural characterization also demonstrated an improved thermally grown oxide scale containing lower spinels in nano-TBC system after 120 h of oxidation. This phenomenon is mainly related to the unique structure of the nano-YSZ coating, which acted as a strong barrier for oxygen diffusion into the TBC system at elevated temperatures. Nearly continues but thinner Al2O3 layer formation at the NiCrAlY/nano-YSZ interface was seen, due to lower oxygen infiltration into the system. Under this condition, spinels formation and growth on the Al2O3 oxide scale were diminished in nano-TBC system compared to normal TBC system.

  16. Ni/YSZ electrode degradation studied by impedance spectroscopy — Effect of p(H2O)

    DEFF Research Database (Denmark)

    Hauch, Anne; Mogensen, Mogens Bjerg; Hagen, Anke

    2011-01-01

    Anode supported solid oxide fuel cells have been tested and the degradation over time was monitored and analyzed by impedance spectroscopy. Reproducibility of initial cathode, anode and electrolyte performance was obtained. Anode (Ni/YSZ) degradation was analyzed for tests applying p(H2O) of 0...

  17. Sensitization of p-type NiO using n-type conducting polymers

    NARCIS (Netherlands)

    Chavhan, S.D.; Abellon, R.D.; Breemen, A.J.J.M. van; Koetse, M.M.; Sweelssen, J.; Savenije, T.J.

    2010-01-01

    We report on the sensitization of a p-type inorganic semiconductor, NiO, by n-type conjugated polymers. NiO thin films were deposited using RF sputtering in pure Ar (NiO A) or in Ar + O2 (90% + 10%) (NiO B). XPS and Kelvin probe measurements indicate the incorporation of oxygen in NiO B

  18. Sensitization of p-type NiO using n-type conducting polymers

    NARCIS (Netherlands)

    Chavhan, S.D.; Abellon, R.D.; Breemen, A.J.J.M. van; Koetse, M.M.; Sweelssen, J.; Savenije, T.J.

    2010-01-01

    We report on the sensitization of a p-type inorganic semiconductor, NiO, by n-type conjugated polymers. NiO thin films were deposited using RF sputtering in pure Ar (NiO A) or in Ar + O2 (90% + 10%) (NiO B). XPS and Kelvin probe measurements indicate the incorporation of oxygen in NiO B l

  19. Sensitization of p-type NiO using n-type conducting polymers

    NARCIS (Netherlands)

    Chavhan, S.D.; Abellon, R.D.; Breemen, A.J.J.M. van; Koetse, M.M.; Sweelssen, J.; Savenije, T.J.

    2010-01-01

    We report on the sensitization of a p-type inorganic semiconductor, NiO, by n-type conjugated polymers. NiO thin films were deposited using RF sputtering in pure Ar (NiO A) or in Ar + O2 (90% + 10%) (NiO B). XPS and Kelvin probe measurements indicate the incorporation of oxygen in NiO B l

  20. In operando characterization of ion gel gating in electrochemical polythiophene transistors

    Science.gov (United States)

    Brady, Michael; Chabinyc, Michael; Hexemer, Alexander; Wang, Cheng

    To progress structural understanding of soft matter in electrochemical devices, it is critical to observe such structural detail in operando such that correlations among material choice, processing, structure, and performance are well formed. We explore these correlations in a novel TFT device, one in which the dielectric layer is a mobile ion gel comprised of a matrix polymer and ionic liquid. This design enables the low-voltage (1 - 2 V) operation of a high mobility P3HT transistor and has applications in low power electronics. Specifically, this work details the development of an in-situ sample environment for the characterization of TFTs under bias, using synchrotron X-ray scattering instruments such as GIWAXS, GISAXS, and RSoXS. Of particular interest are GIWAXS for characterization of the ion-crystallite interaction in P3HT and GISAXS for measuring the change in domain structure as ion channels form during biasing. Additionally, RSoXS is a critical tool for analyzing the composition profile of mobile ions within each layer with reflectivity, as well as for the characterization of domain swelling caused by ion infiltration. Generally, we have found that the mobile anion is a critical species in the electrochemical doping of P3HT, whereby this ion swells the P3HT layer and causes crystallite disordering. The dynamics of ion motion and the resulting effects on polymer structure will be of particular focus in in-situ GIWAXS and RSoXS measurements.

  1. Direct observation of lithium polysulfides in lithium-sulfur batteries using operando X-ray diffraction

    Science.gov (United States)

    Conder, Joanna; Bouchet, Renaud; Trabesinger, Sigita; Marino, Cyril; Gubler, Lorenz; Villevieille, Claire

    2017-06-01

    In the on going quest towards lithium-battery chemistries beyond the lithium-ion technology, the lithium-sulfur system is emerging as one of the most promising candidates. The major outstanding challenge on the route to commercialization is controlling the so-called polysulfide shuttle, which is responsible for the poor cycling efficiency of the current generation of lithium-sulfur batteries. However, the mechanistic understanding of the reactions underlying the polysulfide shuttle is still incomplete. Here we report the direct observation of lithium polysulfides in a lithium-sulfur cell during operation by means of operando X-ray diffraction. We identify signatures of polysulfides adsorbed on the surface of a glass-fibre separator and monitor their evolution during cycling. Furthermore, we demonstrate that the adsorption of the polysulfides onto SiO2 can be harnessed for buffering the polysulfide redox shuttle. The use of fumed silica as an electrolyte additive therefore significantly improves the specific charge and Coulombic efficiency of lithium-sulfur batteries.

  2. In operando infrared spectroscopy of lithium polysulfides using a novel spectro-electrochemical cell

    Science.gov (United States)

    Saqib, Najmus; Ohlhausen, Gretchen M.; Porter, Jason M.

    2017-10-01

    A new in operando spectro-electrochemical Li-S cell has been demonstrated. The novel design allows investigations of the liquid electrolyte phase, in a commercial coin cell geometry, at C rates much higher than conventional in situ cells. We use ATR FT-IR spectroscopy, coupled with a previously developed polysulfide diagnostic to quantify the evolution of lithium polysulfides during the discharge and charge cycles of a Li-S cell. The trends observed in the polysulfide order and concentration with respect to state of charge are consistent with prevailing understanding of the electrochemical mechanisms of Li-S battery operation. During discharge, we observe the reduction of elemental sulfur to dissolved Li2S8 polysulfides, and their cascading conversion to smaller polysulfides until insoluble species (Li2S2 and Li2S) are formed. During cell charging, we observe the oxidation of insoluble polysulfides to larger, soluble polysulfides (Li2Sn , n > 3), and infer an eventual recovery of crystalline sulfur, from changes in polysulfides. Long-term evolution of polysulfides is observed over 7 discharge/charge cycles. Capacity fading is evident in the decay of polysulfide order and concentration at the same state of charge between cycles. Sulfur is not recovered by charging the cell in the latter cycles, and the active material is lost as solid Li2S .

  3. Maximizing the power density of aqueous electrochemical flow cells with in operando deposition

    Science.gov (United States)

    Goulet, Marc-Antoni; Ibrahim, Omar A.; Kim, Will H. J.; Kjeang, Erik

    2017-01-01

    To transition toward sustainable energy systems, next generation power sources must provide high power density at minimum cost. Using inexpensive and environmentally friendly fabrication methods, this work describes a room temperature electrochemical flow cell with a maximum power density of 2.01 W cm-2 or 13.4 W cm-3. In part, this is achieved by minimizing ohmic resistance through decreased electrode spacing, implementation of current collectors and improvement of electrolyte conductivity. The majority of the performance gain is provided by a novel in operando dynamic flowing deposition method for which the cell design has been optimized. Carbon nanotubes (CNTs) are deposited dynamically at the entrance of and within the carbon paper electrodes during operation of the cell. A natural equilibrium is reached between deposition and detachment of CNTs at which the electrochemical surface area and pore size distribution of the flow-through porous electrodes are greatly enhanced. In this way, the novel deposition method more than doubles the power density of the cell and sets a new performance benchmark for what is practically attainable with aqueous electrochemical flow cells. Overall, it is expected that the design and operation methods illustrated here will enable a wide range of electrochemical flow cell technologies to achieve optimal performance.

  4. Realizing NiO nanocrystals from a simple chemical method

    Indian Academy of Sciences (India)

    Neelabh Srivastava; P C Srivastava

    2010-12-01

    Nanocrystalline NiO has been prepared successfully by a simple chemical route using NiCl2.6H2O and NaOH aqueous solution at a temperature of 70°C. The prepared material has been characterized from XRD, SEM, and M–H characteristics. It has been found that NiO nanocrystals have been formed which shows a superparamagnetic/superantiferromagnetic behaviour.

  5. Greedy Snake Video Game Based on Nios II System

    OpenAIRE

    2014-01-01

    With the development of large scale integrated circuit, traditional embedded system design method cannot meet the requirements for building complex systems. Therefore, SOC and SOPC technology are widely used nowadays. This thesis aims to development a game platform based on Nios II system using Altera DE2 development and education board and SOPC technology. In this thesis, first a custom Nios II system was built according to the requirements of the game application. The system contains hardwa...

  6. Ni/Ni-YSZ current collector/anode dual layer hollow fibers for micro-tubular solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Kanawka, K.; Othman, M.H.D.; Droushiotis, N.; Wu, Z.; Kelsall, G.; Li, K. [Department of Chemical Engineering and Chemical Technology, Imperial College London, London SW7 2AZ (United Kingdom)

    2011-10-15

    A co-extrusion technique was employed to fabricate a novel dual layer NiO/NiO-YSZ hollow fiber (HF) precursor which was then co-sintered at 1,400 C and reduced at 700 C to form, respectively, a meshed porous inner Ni current collector and outer Ni-YSZ anode layers for SOFC applications. The inner thin and highly porous ''mesh-like'' pure Ni layer of approximately 50 {mu}m in thickness functions as a current collector in micro-tubular solid oxide fuel cell (SOFC), aiming at highly efficient current collection with low fuel diffusion resistance, while the thicker outer Ni-YSZ layer of 260 {mu}m acts as an anode, providing also major mechanical strength to the dual-layer HF. Achieved morphology consisted of short finger-like voids originating from the inner lumen of the HF, and a sponge-like structure filling most of the Ni-YSZ anode layer, which is considered to be suitable macrostructure for anode SOFC system. The electrical conductivity of the meshed porous inner Ni layer is measured to be 77.5 x 10{sup 5} S m{sup -1}. This result is significantly higher than previous reported results on single layer Ni-YSZ HFs, which performs not only as a catalyst for the oxidation reaction, but also as a current collector. These results highlight the advantages of this novel dual-layer HF design as a new and highly efficient way of collecting current from the lumen of micro-tubular SOFC. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Improvement of adhesion and barrier properties of biomedical stainless steel by deposition of YSZ coatings using RF magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Sánchez-Hernández, Z.E. [Instituto Politécnico Nacional, CICATA-Altamira, Grupo CIAMS, Km 14.5, Carretera Tampico-Puerto Industrial Altamira, C. P. 89600, Altamira, Tamps, México (Mexico); CICATA—Altamira, IPN. Grupo CIAMS, Km 14.5, Carretera Tampico-Puerto Industrial Altamira, C. P. 89600, Altamira, Tamps, México (Mexico); Domínguez-Crespo, M.A., E-mail: mdominguezc@ipn.mx [Instituto Politécnico Nacional, CICATA-Altamira, Grupo CIAMS, Km 14.5, Carretera Tampico-Puerto Industrial Altamira, C. P. 89600, Altamira, Tamps, México (Mexico); Torres-Huerta, A.M.; Onofre-Bustamante, E. [Instituto Politécnico Nacional, CICATA-Altamira, Grupo CIAMS, Km 14.5, Carretera Tampico-Puerto Industrial Altamira, C. P. 89600, Altamira, Tamps, México (Mexico); Andraca Adame, J. [Instituto Politécnico Nacional, Centro de Nanociencias Micro y Nanotecnologías, Departamento de DRX, C. P. 07300, Mexico, DF, México (Mexico); Dorantes-Rosales, H. [Instituto Politécnico Nacional, ESIQIE, Departamento de Metalurgia, C. P. 07300 Mexico, DF, México (Mexico)

    2014-05-01

    The AISI 316L stainless steel (SS) has been widely used in both artificial knee and hip joints in biomedical applications. In the present study, yttria stabilized zirconia (YSZ, ZrO{sub 2} + 8% Y{sub 2}O{sub 3}) films were deposited on AISI 316L SS by radio-frequency magnetron sputtering using different power densities (50–250 W) and deposition times (30–120 min) from a YSZ target. The crystallographic orientation and surface morphology were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The effects of the surface modification on the corrosion performance of AISI 316L SS were evaluated in phosphate buffered saline (PBS) solution using an electrochemical test on both the virgin and coated samples. The YSZ coatings have a (111) preferred orientation during crystal growth along the c-axis for short deposition times (30–60 min), whereas a polycrystalline structure forms during deposition times from 90 to 120 min. The corrosion protective character of the YSZ coatings depends on the crystal size and film thickness. A significant increase in adhesion and corrosion resistance by at least a factor of 46 and a higher breakdown potential were obtained for the deposited coatings at 200 W (120 min). - Highlights: • Well-formed and protective YSZ coatings were achieved on AISI 316L SS substrates. • Films grown at high power and long deposition time have polycrystalline structures. • The crystal size varies from ∼ 5 to 30 nm as both power and deposition time increased. • The differences of corrosion resistance are attributed to internal film structure.

  8. PATRIMÔNIO: SIMBIOSE HOMEM-MEIOAMBIENTE

    Directory of Open Access Journals (Sweden)

    Maurí Bessegatto

    2012-09-01

    Full Text Available Aspiramos levantar alguns parâmetros  reflexivos referentes aproficuidade da temática da Educação Patrimonial na contemporaneidade.Como agentes irradiadores da Educação Patrimonial, objetivamos despertar o interesse nas comunidades, com a novidade do tema, problematizando-o, para que possam construir o conhecimento, desenvolvendo o objetivo básico que é de torná-los sujeitos históricos, desenvolvendo a cidadania.PALAVRAS-CHAVE: patrimônio cultural e ambiental; homem; futuro.ABSTRACT:We aspire to raise some reflexive parameters about the successful of subject matter of heritage education nowadays. Like broadcasters of heritage education, hope to awake the benefit in the communities, with the new topic, to that they can built the knowledge, developing the basic target that is become them in historic subjects, developing the citizenship. KEY-WORKS: cultural and environmental patrimony; man; future.

  9. Methane Steam Reforming over an Ni-YSZ Solid Oxide Fuel Cell Anode in Stack Configuration

    Directory of Open Access Journals (Sweden)

    D. Mogensen

    2014-01-01

    Full Text Available The kinetics of catalytic steam reforming of methane over an Ni-YSZ anode of a solid oxide fuel cell (SOFC have been investigated with the cell placed in a stack configuration. In order to decrease the degree of conversion, a single cell stack with reduced area was used. Measurements were performed in the temperature range 600–800°C and the partial pressures of all reactants and products were varied. The obtained rates could be well fitted with a power law expression (r ∝PCH40.7. A simple model is presented which is capable of predicting the methane conversion in a stack configuration from intrinsic kinetics of the anode support material. The predictions are compared with the stack measurements presented here, and good agreement is observed.

  10. Effect of sintering temperature on microstructure and performance of LSM-YSZ composite cathodes

    DEFF Research Database (Denmark)

    Juhl Jørgensen, M.; Primdahl, S.; Bagger, C.;

    2001-01-01

    at the interface between the composite and the current collector. This interface is assumed to become more important with respect to oxygen reduction as the sintering temperature of the composite layer is increased, due to loss of porosity in this layer. An experiment with in-situ sintering of the composite......The correlation between sintering temperature, microstructure and performance of composite electrodes comprising lanthanum strontium manganate (LSM) and yttria stabilised zirconia (YSZ) with a current collector of LSM has been studied at 1000 degreesC in air. The microstructure was found to be less...... temperature. When keeping the sintering temperature of the composite structure constant at 1300 degreesC the performance was found to improve when lowering the sintering temperature of the current collector, This may suggest that a large part of the sites, which are active to oxygen reduction, are situated...

  11. Microstructural degradation of Ni-YSZ anodes for solid oxide fuel cells

    DEFF Research Database (Denmark)

    Thydén, Karl Tor Sune

    2008-01-01

    are of technological relevance, it is difficult to identify the effect from isolated parameters such as temperature, fuel gas composition and polarization. Model studies of high temperature aged Ni-YSZ cermets are generally performed in atmospheres containing relatively low concentrations of H2O. In this work......, the microstructural degradation in both electrochemically longterm tested cells and high-temperature aged model materials are studied. Since Ni particle sintering / coarsening is attributed to be the major cause of anode degradation, this subject attains the primary focus. A large part of the work is focused......-reforming catalysis. In the context of electrochemically tested and technologically relevant cells, the majority of the microstructural work is performed on a cell tested at 850°C under relatively severe conditions for 17,500 hours. It is demonstrated that the major Ni rearrangements take place at the interface...

  12. Dense zig-zag microstructures in YSZ thin films by pulsed laser deposition

    Directory of Open Access Journals (Sweden)

    Dieter Stender

    2015-01-01

    Full Text Available The very brittle oxygen ion conductor yttria stabilized zirconia (YSZ is a typical solid electrolyte for miniaturized thin film fuel cells. In order to decrease the fuel cell operating temperature, the thickness of yttria stabilized zirconia thin films is reduced. Often, these thin membranes suffer from mechanical failure and gas permeability. To improve these mechanical issues, a glancing angle deposition approach is used to grow yttria stabilized zirconia thin films with tilted columnar structures. Changes of the material flux direction during the deposition result in a dense, zigzag-like structure with columnar crystallites. This structure reduces the elastic modulus of these membranes as compared to columnar yttria stabilized zirconia thin films as monitored by nano-indentation which makes them more adaptable to applied stress.

  13. Preparation and application of YSZ thin films%YSZ薄膜的制备及应用

    Institute of Scientific and Technical Information of China (English)

    潘礼庆; 王岭; 孙加林; 洪彦若

    2000-01-01

    研究了在NASICON基板上使用溅射法制备的YSZ薄膜的结构、晶相和导电性,实验表明,刚制备的YSZ薄膜经750℃常规退火处理后,薄膜表面致密、均匀、无裂纹,具备良好的导电性能.YSZ/NASICON组合再加上Ba(NO3)2辅助电极构成的NOX气体传感器在450℃下响应迅速(响应时间约为3min)、稳定,能检测到10ppm量级的NO2气体.

  14. Development and characterization of composite YSZ-PEI electrophoretically deposited membrane for Li-ion battery.

    Science.gov (United States)

    Hadar, R; Golodnitsky, D; Mazor, H; Ripenbein, T; Ardel, G; Barkay, Z; Gladkich, A; Peled, E

    2013-02-14

    In this work, the electrophoretic-deposition (EPD) method was used to fabricate pristine and composite ceramic-polymer membranes for application in planar and 3D microbattery configurations. The major focus was on the effect of polyethyleneimine additive on the morphology, composition, and electrochemical properties of the membrane. The ionic conductivity, cycleability, and charge/discharge behavior of planar LiFePO(4)/Li cells comprising composite porous YSZ-based membrane with impregnated LiPF(6) EC:DEC electrolyte were found to be similar to the cells with commercial Celgard membrane. Conformal EPD coating of the electrode materials by a thin-film ceramic separator is advantageous for high-power operation and safety of batteries.

  15. Study of YSZ-based electrochemical sensors with oxide electrodes for high temperature applications

    Indian Academy of Sciences (India)

    A Dutta; N Kaabbuathong; M L Grilli; E Di Bartolomeo; E Traversa

    2002-11-01

    Potentiometric sensors based on yttria stabilized zirconia (YSZ) with WO3 as sensing electrode were fabricated using either Pt or Au electrodes. The sensors were studied in the temperature range 550–700°C in the presence of different concentrations (300–1000 ppm) of NO2 and CO in air. The response to NO2 was very stable with fast response time (20–40 s). The best sensitivity (18.8 mV/decade) using Pt electrodes was observed at 600°C. At the same temperature a cross-sensitivity (– 15 mV/decade) to CO gas was also noticed. The response to CO was decreased (– 4 mV/decade) using Au electrode. The role played by WO3 on the sensing electrode was discussed.

  16. Optimization of dry reforming of methane over Ni/YSZ anodes for solid oxide fuel cells

    Science.gov (United States)

    Guerra, Cosimo; Lanzini, Andrea; Leone, Pierluigi; Santarelli, Massimo; Brandon, Nigel P.

    2014-01-01

    This work investigates the catalytic properties of Ni/YSZ anodes as electrodes of Solid Oxide Fuel Cells (SOFCs) to be operated under direct dry reforming of methane. The experimental test rig consists of a micro-reactor, where anode samples are characterized. The gas composition at the reactor outlet is monitored using a mass spectrometer. The kinetics of the reactions occurring over the anode is investigated by means of Isotherm reactions and Temperature-programmed reactions. The effect of the variation of temperature, gas residence time and inlet carbon dioxide-methane volumetric ratio is analyzed. At 800 °C, the best catalytic performance (in the carbon safe region) is obtained for 1.5 dry reforming and cracking reactions, respectively. In other ranges, dry reforming and reverse water gas shift are the dominant reactions and the inlet feed reaches almost the equilibrium condition provided that a sufficient gas residence time is obtained.

  17. Microstructure degradation of LSM-YSZ cathode in SOFCs operated at various conditions

    DEFF Research Database (Denmark)

    Liu, Yi-Lin; Thydén, Karl Tor Sune; Chen, Ming

    2012-01-01

    mechanisms have been identified. And it has been observed that different mechanisms dominate the degradation process under different test conditions. The severe cathode degradation at 750 °C operation with high current density is attributed to a loss of the cathode/electrolyte interface stability......Systematic microstructural analyses have been carried out on a series of technological SOFCs that went through long-term cell tests with various operating parameters including temperature, current load and time length under current. For the LSM-YSZ cathode, a number of microstructure degradation....... For the cells tested at 850 °C, the interface stability is maintained due to further sintering during cell operation. A cell test lasting for 2 years (17500 h) at 850 °C with a moderate current density (not greater than 1 A/cm2) has shown that the cathode microstructure is fairly robust to the degradation...

  18. Thermal stability and hcp-fcc allotropic transformation in supported Co metal catalysts probed near operando by ferromagnetic NMR.

    Science.gov (United States)

    Andreev, Andrey S; d'Espinose de Lacaillerie, Jean-Baptiste; Lapina, Olga B; Gerashenko, Alexander

    2015-06-14

    Despite the fact that cobalt based catalysts are used at the industrial scale for Fischer-Tropsch synthesis, it is not yet clear which cobalt metallic phase is actually at work under operando conditions and what is its state of dispersion. As it turns out, the different phases of metallic cobalt, fcc and hcp, give rise to distinct ferromagnetic nuclear magnetic resonance. Furthermore, within one Co metal particle, the occurrence of several ferromagnetic domains of limited sizes can be evidenced by the specific resonance of Co in multi-domain particles. Consequently, by ferromagnetic NMR, one can follow quantitatively the sintering and phase transitions of dispersed Co metal particles in supported catalysts under near operando conditions. The minimal size probed by ferromagnetic Co NMR is not precisely known but is considered to be in the order of 10 nm for supported Co particles at room temperature and increases to about 35 nm at 850 K. Here, in Co metal Fischer-Tropsch synthesis catalysts supported on β-SiC, the resonances of the fcc multi-domain, fcc single-domain and hcp Co were clearly distinguished. A careful rationalization of their frequency and width dependence on temperature allowed a quantitative analysis of the spectra in the temperature range of interest, thus reflecting the state of the catalysts under near operando conditions that is without the uncertainty associated with prior quenching. The allotropic transition temperature was found to start at 600-650 K, which is about 50 K below the bulk transition temperature. The phase transition was fully reversible and a significant part of the hcp phase was found to be stable up to 850 K. This anomalous behavior that was observed without quenching might prove to be crucial to understand and model active species not only in catalysts but also in battery materials.

  19. Spinel materials for Li-ion batteries: new insights obtained by operando neutron and synchrotron X-ray diffraction.

    Science.gov (United States)

    Bianchini, Matteo; Fauth, François; Suard, Emmanuelle; Leriche, Jean Bernard; Masquelier, Christian; Croguennec, Laurence

    2015-12-01

    In the last few decades Li-ion batteries changed the way we store energy, becoming a key element of our everyday life. Their continuous improvement is tightly bound to the understanding of lithium (de)intercalation phenomena in electrode materials. Here we address the use of operando diffraction techniques to understand these mechanisms. We focus on powerful probes such as neutrons and synchrotron X-ray radiation, which have become increasingly familiar to the electrochemical community. After discussing the general benefits (and drawbacks) of these characterization techniques and the work of customization required to adapt standard electrochemical cells to an operando diffraction experiment, we highlight several very recent results. We concentrate on important electrode materials such as the spinels Li1 + xMn2 - xO4 (0 ≤ x ≤ 0.10) and LiNi0.4Mn1.6O4. Thorough investigations led by operando neutron powder diffraction demonstrated that neutrons are highly sensitive to structural parameters that cannot be captured by other means (for example, atomic Debye-Waller factors and lithium site occupancy). Synchrotron radiation X-ray powder diffraction reveals how LiMn2O4 is subject to irreversibility upon the first electrochemical cycle, resulting in severe Bragg peak broadening. Even more interestingly, we show for the first time an ordering scheme of the elusive composition Li0.5Mn2O4, through the coexistence of Mn(3+):Mn(4+) 1:3 cation ordering and lithium/vacancy ordering. More accurately written as Li0.5Mn(3+)0.5Mn(4+)1.5O4, this intermediate phase loses the Fd\\overline 3m symmetry, to be correctly described in the P213 space group.

  20. Efeito da geometria do bocal divergente sobre o empuxo de motor-foguete operando no vácuo

    OpenAIRE

    Moro,Diego Fernando

    2014-01-01

    Orientador : Prof. Dr. Carlos Henrique Marchi Dissertação (mestrado) - Universidade Federal do Paraná, Setor de Tecnologia, Programa de Pós-Graduação em Engenharia Mecânica. Defesa: Curitiba, 25/08/2014 Inclui referências Área de concentração: Fenômenos de transporte e mecânica dos sólidos Resumo: O objetivo deste trabalho foi avaliar o efeito da parte divergente de motores-foguete operando no vácuo. Para isto, foram realizadas simulações com o código computacional Mach2D. N...

  1. Operando XPS Characterization of Selective Contacts: The Case of Molybdenum Oxide for Crystalline Silicon Heterojunction Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Laura; Harvey, Stephen P.; Teeter, Glenn; Bertoni, Mariana I.

    2016-11-21

    We demonstrate the potential of X-ray photoelectron spectroscopy (XPS) to characterize new carrier-selective contacts (CSC) for solar cell application. We show that XPS not only provides information about the surface chemical properties of the CSC material, but that operando XPS, i.e. under light bias condition, can also directly measure the photovoltage that develops at the CSC/absorber interface, revealing device relevant information without the need of assembling a full solar cell. We present the application of the technique to molybdenum oxide hole-selective contact films on a crystalline silicon absorber.

  2. An electrochemical cell for in operando studies of lithium/sodium batteries using a conventional x-ray powder diffractometer

    DEFF Research Database (Denmark)

    Shen, Yanbin; Pedersen, Erik Ejler; Christensen, Mogens

    2014-01-01

    An electrochemical cell has been designed for powder X-ray diffraction (PXRD) studies of lithium ion batteries (LIB) and sodium ion batteries (SIB) in operando with high time resolution using conventional powder X-ray diffractometer. The cell allows for studies of both anode and cathode electrode...... materials in reflection mode. The cell design closely mimics that of standard battery testing coin cells and allows obtaining powder X-ray diffraction patterns under representative electrochemical conditions. In addition, the cell uses graphite as the X-ray window instead of beryllium, and it is easy...

  3. Identification of nickel sulfides on Ni-YSZ cermet exposed to H 2 fuel containing H 2S using Raman spectroscopy

    Science.gov (United States)

    Dong, Jian; Cheng, Zhe; Zha, Shaowu; Liu, Meilin

    Ni-YSZ cermet was exposed to hydrogen containing different concentrations of H 2S to identify the phases formed under various conditions using Raman spectroscopy and X-ray diffraction (XRD). For Ni-YSZ samples exposed to hydrogen containing 100 ppm H 2S at 727 °C for 5 days, thermodynamic calculations indicate that Ni-YSZ would be stable and XRD analysis was unable to detect any changes. However, the vibration modes of Ni 3S 2 were detected using Raman spectroscopy, suggesting that Raman spectroscopy could be a powerful tool for in situ study of sulfur poisoning of SOFC anodes. For Ni-YSZ cermet exposed to hydrogen containing 10% H 2S at 950 °C for 5 days, Ni was converted to nickel sulfide, and vibration modes of NiS were detected using Raman spectroscopy.

  4. Microstructural and electrical characterization of Nb-doped SrTiO3–YSZ composites for solid oxide cell electrodes

    DEFF Research Database (Denmark)

    Reddy Sudireddy, Bhaskar; Blennow Tullmar, Peter; Nielsen, Karsten Agersted

    2012-01-01

    Nb-doped SrTiO3 (Sr1 − xTi0.9Nb0.1O3, x = 0.01 and 0.06, henceforth known as STN) and 8 mol% Y2O3 stabilized ZrO2 (8YSZ) composites were prepared by mixing them in different volume fractions between 10 vol.% and 50 vol.% of 8YSZ. The composites were compacted into pellets, sintered and evaluated...... phases. However, microstructural analysis revealed segregation and formation of Nb enriched particles in the 50 vol.% 8YSZ composite. Chemical analysis by energy dispersive spectroscopy (EDS) also showed the inter-diffusion of elements (especially Ti from STN and Zr from 8YSZ) from both phases on small...

  5. Electrochromic performances of nonstoichiometric NiO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Moulki, H.; Faure, C. [CNRS, Univ. Bordeaux, ICMCB, UPR 9048, F-33600 Pessac (France); Mihelčič, M.; Vuk, A. Šurca [National Institute of Chemistry, NIC, Hajdrihova 19, SI-1000 Ljubljana (Slovenia); Švegl, F. [Amanova Ltd., Tehnološki Park 18, SI-1000 Ljubljana (Slovenia); Orel, B. [National Institute of Chemistry, NIC, Hajdrihova 19, SI-1000 Ljubljana (Slovenia); Campet, G. [CNRS, Univ. Bordeaux, ICMCB, UPR 9048, F-33600 Pessac (France); Alfredsson, M.; Chadwick, A.V. [Functional Materials Group, School of Physical Sciences, University of Kent, Canterbury, Kent CT2 7NH (United Kingdom); Gianolio, D. [Diamond Light Source Ltd., Harwell Science and Innovation Campus, OX11 0DE Didcot (United Kingdom); Rougier, A., E-mail: Rougier@icmcb-bordeaux.cnrs.fr [CNRS, Univ. Bordeaux, ICMCB, UPR 9048, F-33600 Pessac (France)

    2014-02-28

    Electrochromic (EC) performances of Ni{sup 3+} containing NiO thin films, called modified NiO thin films, prepared either by pulsed laser deposition or by chemical route are reported. When cycled in lithium based electrolyte, the comparison of the EC behavior of nonstoichiometric NiO thin films points out a larger optical contrast for the films synthesized by chemical route with the absence of an activation period on early electrochemical cycling due in particular to a larger porosity. Herein we demonstrate faster kinetics for modified NiO thin films cycled in lithium ion free electrolyte. Finally, X-ray absorption spectroscopy is used for a preliminary understanding of the mechanism involved in this original EC behavior linked to the film characteristics including their disorder character, the presence of Ni{sup 3+} and their porous morphology. - Highlights: • Nonstoichiometric NiO thin films • Electrochromic performances in lithium free electrolyte • X-ray absorption spectroscopy investigation of as-deposited films and upon cycling.

  6. The effect of heat treatment and thermal spray processes on the grain growth of nanostructured composite CoNiCrAlY/YSZ powders

    Energy Technology Data Exchange (ETDEWEB)

    Tahari, Mostafa, E-mail: fa.tahari@yahoo.com [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Department of Engineering, Esfarayen University of Technology, Esfarayen-North Khorasan 96619-98195 (Iran, Islamic Republic of); Shamanian, Morteza; Salehi, Mehdi [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

    2015-10-15

    This research investigated thermal stability of mechanically milled MCrAlY/YSZ composites during heat treatment and high velocity oxy-fuel (HVOF) thermal spray processes. MCrAlY powder was mixed with 5%, 10% and 15% YSZ and then milled for 12 and 24 h. A powder without YSZ reinforcement ball was milled for 12 and 24 h too. The composite powders were annealed for 10 h at 1273 K to investigate thermal stability. Nanocrystalline and commercial powders were deposited on Inconel-617 substrate using the HVOF process. The morphology and thermal stability of mechanically milled and heat treated powders and coatings were investigated using X-ray diffractometry, scanning electron microscopy (SEM) and optical microscopy (OM). It was found that the increase in milling time resulted in the uniform distribution of reinforcements in the γ phase matrix. The uniform distribution of reinforcements caused reduction in grain growth during heat treatment process. On the other hand, increasing YSZ percentage decreased grain growth, but when the YSZ amount exceeded 10%, the ceramic reinforcements could not prevent the grain growth of nanostructure powders. The heat absorbed by nanostructured powders during thermal spraying process resulted in the grain growth of the γ-phase, but due to the presence of YSZ reinforcement, the grain growth was very lower than that of unreinforced coatings. It could be suggested that nanostructure coating formed due to thermo mechanical phenomena occurred in commercial powder particles during thermal spray process. - Highlights: • CoNiCrAlY/YSZ composite. • Nanostructure powder. • Heat treatment of CoNiCrAlY/YSZ.

  7. Operando UV-Vis spectroscopy of a catalytic solid in a pilos-scale reactor: deactivation of a CrOx/Al2O3 propane dehydrogenation catalyst

    NARCIS (Netherlands)

    Sattler, J.J.H.B.|info:eu-repo/dai/nl/328235601; Gonzalez-Jimenez, I.D.; Mens, A.J.M.|info:eu-repo/dai/nl/313707065; Arias, M.J.|info:eu-repo/dai/nl/314076727; Visser, T.|info:eu-repo/dai/nl/110288327; Weckhuysen, B.M.|info:eu-repo/dai/nl/285484397

    2013-01-01

    A novel operando UV-Vis spectroscopic set-up has been constructed and tested for the investigation of catalyst bodies loaded in a pilot-scale reactor under relevant reaction conditions. Spatiotemporal insight into the formation and burning of coke deposits on an industrial CrOx/Al2O3 catalyst during

  8. Real-Time Quantitative Operando Raman Spectroscopy of a CrOx/Al2O3 Propane Dehydrogenation Catalyst in a Pilot-Scale Reactor

    NARCIS (Netherlands)

    Sattler, Jesper J. H. B.|info:eu-repo/dai/nl/328235601; Mens, Ad M.; Weckhuysen, Bert M.|info:eu-repo/dai/nl/285484397

    2014-01-01

    Combined operando UV/vis-Raman spectroscopy has been used to study the deactivation of CrOx/Al2O3 catalyst extrudates in a pilot scale propane dehydrogenation reactor. For this purpose, UV/vis and Raman optical fiber probes have been designed, constructed and tested. The light absorption measured by

  9. Combined Operando UV/Vis/IR Spectroscopy Reveals the Role of Methoxy and Aromatic Species during the Methanol-to-Olefins Reaction over H-SAPO-34

    NARCIS (Netherlands)

    Qian, Qingyun; Vogt, Charlotte; Mokhtar, Mohamed; Asiri, Abdullah M.; Al-Thabaiti, Shaeel A.; Basahel, Suliman N.; Ruiz-Martinez, Javier; Weckhuysen, Bert M.

    2014-01-01

    The methanol-to-olefins (MTO) process over H-SAPO-34 is investigated by using an operando approach combining UV/Vis and IR spectroscopies with on-line mass spectrometry. Methanol, methoxy, and protonated dimethyl ether are the major species during the induction period, whereas polyalkylated benzenes

  10. Molybdenum Speciation and its Impact on Catalytic Activity during Methane Dehydroaromatization in Zeolite ZSM-5 as Revealed by Operando X-Ray Methods

    NARCIS (Netherlands)

    Lezcano-González, Inés; Oord, R.; Rovezzi, Mauro; Glatzel, Pieter; Botchway, Stanley W; Weckhuysen, Bert M; Beale, Andrew M

    2016-01-01

    Combined high-resolution fluorescence detection X-ray absorption near-edge spectroscopy, X-ray diffraction, and X-ray emission spectroscopy have been employed under operando conditions to obtain detailed new insight into the nature of the Mo species on zeolite ZSM-5 during methane dehydroaromatizati

  11. Operando UV-Vis spectroscopy of a catalytic solid in a pilos-scale reactor: deactivation of a CrOx/Al2O3 propane dehydrogenation catalyst

    NARCIS (Netherlands)

    Sattler, J.J.H.B.; Gonzalez-Jimenez, I.D.; Mens, A.J.M.; Arias, M.J.; Visser, T.; Weckhuysen, B.M.

    2013-01-01

    A novel operando UV-Vis spectroscopic set-up has been constructed and tested for the investigation of catalyst bodies loaded in a pilot-scale reactor under relevant reaction conditions. Spatiotemporal insight into the formation and burning of coke deposits on an industrial CrOx/Al2O3 catalyst during

  12. Improvement of epitaxy and crystallinity in YBa2Cu3Oy thin films grown on silicon with double buffer of ECO/YSZ

    Institute of Scientific and Technical Information of China (English)

    GAO Ju; YANG Jian

    2006-01-01

    A novel double buffer of Eu2CuO4 (ECO)/YSZ (yttrium-stabilized zirconia) was developed for growing YBa2Cu3Oy (YBCO) thin films on Si substrates. In these films,the severe reaction between Si and YBCO is blocked by the first YSZ layer,whereas,the degradation of crystallinity and superconductivity in the grown YBCO is greatly improved by the second ECO layer. Such an ECO material possesses a very stable 214-T' structure and excellent compatibilities with YBCO and YSZ. The result shows that the epitaxy and crystallinity of YBCO deposited on Si could be considerably enhanced by using the ECO/YSZ double buffer. The grown films are characterized by high-resolution X-ray diffraction,grazing incidence X-ray reflection,and transmission electron microscopy (TEM),respectively. It is found that well defined interfaces are formed at YBCO/ECO/YSZ boundaries. No immediate layer could be seen. The defect density in all grown layers is kept at a lower level. The YBCO film surface turns out to be very smooth. These films have full superconducting transitions above 88 K and high current carrying capacity at 77 K. The successful growth of highly epitaxial YBCO thin films on silicon with ECO/YSZ buffer,demonstrate the advantages of such a double buffer structure.

  13. Performance of a solid oxide fuel cell with cathode containing a functional layer of LSM/YSZ film; Desempenho de uma celula a combustivel de oxido solido com catodo contendo uma camada funcional de filme LSM/YSZ

    Energy Technology Data Exchange (ETDEWEB)

    Pires, Filipe Oliveira; Domingues, Rosana Z.; Brant, Marcia C.; Silva, Charles L.; Matencio, Tulio [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Quimica]. E-mail: filipequiufmg@ufmg.br

    2008-07-01

    Performance of a SOFC may be evaluated by using the AC-Impedance and measuring power (P V x I). The objective of this study was to compare the performance of a fuel cell with LSM as a cathode and another one containing an additional functional composite film LSM/YSZ between the LSM and YSZ. Also it was studied variation in second cell resistance and power according to the temperature, hydrogen flux and operation time. For both cells platinum was used as anode. At 800 deg C was observed, in open current circuit, when the composite layer was introduced a decrease in resistance and high power. These results show an improvement of SOFC cathode performance with the introduction of composite LSM/YSZ layer. The maximum performance of the cell was achieved with 100 mL/min hydrogen flow at 800 deg C. The experiments also showed a performance improvement at 850 deg C. The cell behavior was stable during 318 hours of test. (author)

  14. Three-dimensional microstructure of high-performance pulsed-laser deposited Ni-YSZ SOFC anodes.

    Science.gov (United States)

    Kennouche, David; Hong, Jongsup; Noh, Ho-Sung; Son, Ji-Won; Barnett, Scott A

    2014-08-07

    The Ni-yttria-stabilized zirconia (YSZ) anode functional layer in solid oxide fuel cells produced by pulsed laser-deposition was studied using three-dimensional tomography. Anode feature sizes of ~130 nm were quite small relative to typical anodes, but errors arising in imaging and segmentation were shown using a sensitivity analysis to be acceptable. Electrochemical characterization showed that these cells achieved a relatively high maximum power density of 1.4 W cm(-2) with low cell resistance at an operating temperature of 600 °C. The tomographic data showed anode three-phase boundary density of ~56 μm(-2), more than 10 times the value observed in conventional Ni-YSZ anodes. Anode polarization resistance values, predicted by combining the structural data and literature values of three-phase boundary resistance in an electrochemical model, were consistent with measured electrochemical impedance spectra, explaining the excellent intermediate-temperature performance of these cells.

  15. Impedance of SOFC electrodes: A review and a comprehensive case study on the impedance of LSM:YSZ cathodes

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Hjelm, Johan

    2014-01-01

    It was shown through a comprehensive impedance spectroscopy study that the impedance of the classic composite LSM:YSZ (lanthanum strontium manganite and yttria stabilized zirconia) solid oxide fuel cell (SOFC) cathode can be described well with porous electrode theory. Furthermore, it was illustr......It was shown through a comprehensive impedance spectroscopy study that the impedance of the classic composite LSM:YSZ (lanthanum strontium manganite and yttria stabilized zirconia) solid oxide fuel cell (SOFC) cathode can be described well with porous electrode theory. Furthermore...... acquired in the very broad temperature range of 200–900°C for complete elucidation of the impedance. All impedance spectra were analyzed in terms of porous electrode theory. Physical materials parameters were extracted from the analysis, which were in excellent accordance with literature values. Valuable...

  16. Synthesis of YSZ thin films by solar energy annealing of Zr-Y layered structures in solar furnace at PSA

    Energy Technology Data Exchange (ETDEWEB)

    Rodriquez, J.; Martinez, D.; Levinskas, R.; Dudonis, J.; Milcius, D.; Sirvinskaite, V.

    2002-07-01

    Zr-Y thin films were deposited using d.c. magnetron sputter deposition on Si and quartz substrates, A post deposition thermal annealing was performed in solar furnace. This film microstructure, composition and roughness was characterized using XRD, SIMS and AFM techniques. XRD showed formation of t-ysz after treatment at 600 degree centigree in solar furnace, AFM showed increase surface roughness after the thermal annealing. (Author) 10 refs.

  17. Effect of Suspension Plasma-Sprayed YSZ Columnar Microstructure and Bond Coat Surface Preparation on Thermal Barrier Coating Properties

    Science.gov (United States)

    Bernard, Benjamin; Quet, Aurélie; Bianchi, Luc; Schick, Vincent; Joulia, Aurélien; Malié, André; Rémy, Benjamin

    2017-08-01

    Suspension plasma spraying (SPS) is identified as promising for the enhancement of thermal barrier coating (TBC) systems used in gas turbines. Particularly, the emerging columnar microstructure enabled by the SPS process is likely to bring about an interesting TBC lifetime. At the same time, the SPS process opens the way to a decrease in thermal conductivity, one of the main issues for the next generation of gas turbines, compared to the state-of-the-art deposition technique, so-called electron beam physical vapor deposition (EB-PVD). In this paper, yttria-stabilized zirconia (YSZ) coatings presenting columnar structures, performed using both SPS and EB-PVD processes, were studied. Depending on the columnar microstructure readily adaptable in the SPS process, low thermal conductivities can be obtained. At 1100 °C, a decrease from 1.3 W m-1 K-1 for EB-PVD YSZ coatings to about 0.7 W m-1 K-1 for SPS coatings was shown. The higher content of porosity in the case of SPS coatings increases the thermal resistance through the thickness and decreases thermal conductivity. The lifetime of SPS YSZ coatings was studied by isothermal cyclic tests, showing equivalent or even higher performances compared to EB-PVD ones. Tests were performed using classical bond coats used for EB-PVD TBC coatings. Thermal cyclic fatigue performance of the best SPS coating reached 1000 cycles to failure on AM1 substrates with a β-(Ni,Pt)Al bond coat. Tests were also performed on AM1 substrates with a Pt-diffused γ-Ni/γ'-Ni3Al bond coat for which more than 2000 cycles to failure were observed for columnar SPS YSZ coatings. The high thermal compliance offered by both the columnar structure and the porosity allowed the reaching of a high lifetime, promising for a TBC application.

  18. Effects of dopants and trace elements at the Ni / ScYSZ interface

    Energy Technology Data Exchange (ETDEWEB)

    Stenbaek Schmidt, M.

    2008-08-15

    The interfaces between the various materials and phases in solid oxide fuel cells (SOFCs) play a fundamental role, when optimizing SOFC performance. The industrial grade materials commonly used in SOFCs contain numerous impurities. At the catalyst / electrolyte interfaces in SOFC cermet anodes, these impurities are believed to be responsible for losses in electrochemical performance. Impurities such as silica have been shown to segregate to the three phase boundary (TPB) in SOFC cermet anodes. A three-electrode configuration, with a high purity (99.999 %) nickel pointelectrode acting as the working electrode, was used as a simplified model of the SOFC cermet anode. Electrochemical impedance spectroscopy was used to characterise the electrode polarisation resistances on selected electrolyte materials at 850 deg. C in humidified hydrogen atmospheres. Electrode reactions were characterized on two types of scandia and yttria co-doped zirconia electrolytes (ScYSZ) with different purity levels, a ScYSZ electrolyte doped with alumina and an yttria stabilized zirconia (YSZ) electrolyte. A point electrode setup provided a well defined electrode / electrolyte interface (EEI) and TPB during electrochemical characterisation, which, after lifting the electrode off the electrolyte, could be studied by surface analysis techniques. Surface analysis was performed using low acceleration voltage scanning electron microscopy (SEM), atomic force microscopy (AFM), time of flight secondary ion mass spectrometry (ToF-SIMS) and xray photoelectron spectroscopy (XPS). For all electrolyte materials the electrode polarization resistances dropped rapidly during the first 50 hours of measurements at 850 deg. C before stabilising. From ToFSIMS and SEM analysis, rim zones with relatively low impurity concentrations were identified at the outer perimeter of the EEI on the electrolyte surfaces. It was suggested that the rim zones were formed, as the nickel electrode expanded, due to metallic creep

  19. The Ni-YSZ interface - Structure, composition and electrochemical properties at 1000 deg. C

    Energy Technology Data Exchange (ETDEWEB)

    Vels Jensen, Karin

    2002-06-01

    The anode/electrolyte interface in solid oxide fuel cells (SOFC) is known to cause electrical losses. Geometrically simple Ni/Yttria-stabilised zirconia (YSZ) interfaces were examined to gain information on the structural and chemical changes occurring during experiments at 1000 deg. C in an atmosphere of 97% H2/3% H{sub 2}O. Electrochemical impedance spectroscopy at open circuit voltage (OCV) and at anodic and cathodic polarisation (100 mV) was performed. A correlation of the electrical data with the structure development and the chemical composition was attempted. Nickel wires with different impurity content (99.8% Ni and 99.995% Ni) were used to examine the impact of impurities on the polarisation resistance and contact area morphology. The electro polished nickel wires were pressed against a polished 8 mol% YSZ surface. Extensive structural changes from a flat interface to a hill and valley structure were found to occur in the contact area with the impure nickel wire, and a ridge of impurities was built along the rim of the contact area. Impurity particles in the interfacial region were also observed. The impurity phase was described as an alkali silicate glassy phase. No differences were found between polarised and non-polarised samples. With pure nickel wires, however, the microstructures depended on the polarisation/non-polarisation conditions. At non-polarised conditions a hill and valley type structure was found. Anodic polarisation produced an up to 1 {mu}m thick interface layer consisting of nano-sized YSZ particles with some Ni present. At cathodic polarisation both a granulated structure and a hill and valley structure resembling the structure of non-polarised samples were found. Small impurity ridges were surrounding the contact areas on non-polarised and cathodically polarised samples. TOF-SIMS and XPS analyses showed the presence of impurities in both the impure and pure contact areas. The impedance spectroscopy revealed that depending on the

  20. Antiferromagnetic phase transition and spin correlations in NiO

    DEFF Research Database (Denmark)

    Chatterji, Tapan; McIntyre, G.J.; Lindgård, Per-Anker

    2009-01-01

    We have investigated the antiferromagnetic (AF) phase transition and spin correlations in NiO by high-temperature neutron diffraction below and above TN. We show that AF phase transition is a continuous second-order transition within our experimental resolution. The spin correlations manifested...... by this process. We determined the critical exponents =0.328±0.002 and =0.64±0.03 and the Néel temperature TN=530±1 K. These critical exponents suggest that NiO should be regarded as a 3dXY system...

  1. Structural study of Novel (superhard) material: NiO

    Indian Academy of Sciences (India)

    Raja Chauhan; Sadhna Singh

    2008-02-01

    We have investigated the pressure-induced phase transition of NiO and other structural properties using three-body potential approach. NiO undergoes phase transition from B1 (rocksalt) to B2 (CsCl) structure associated with a sudden collapse in volume showing first-order phase transition. A theoretical study of high pressure phase transition and elastic behaviour in transition metal compounds using a three-body potential caused by the electron shell deformation of the overlapping ion was carried out. The phase transition pressure and other properties predicted by our model is closer to the phase transition pressure predicted by Eto et al.

  2. Cathodic micro-arc electrodeposition of yttrium stabilized zirconia (YSZ) coatings on FeCrAl alloy

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The formation of ceramic coatings on metal substrate by cathodic electrolytic deposition (CELD) has received more attention in recent years. But only thin films can be prepared via CELD. Yttrium stabilized zirconia (YSZ) ceramic coatings were deposited on FeCrAl alloy by a novel technique--cathodic micro-arc electrodeposition (CMED). The result shows that, when a high pulse electric field is applied to the cathode which was pre-deposited with a thin YSZ film, dielectric breakdown occurs and micro-arc discharges appear. Coatings with reasonably thickness of ~300μm and crystalline structure can be deposited on the cathode by utilizing the energy of the micro-arc. The thickness of the as-deposited coating is dominated by the voltage and the frequency. Y2O3 is co-deposited with ZrO2 when Y(NO3)3 was added to the electrolyte, which stabilize t-phase, t′- phase and c-phase of ZrO2 at room temperature. The amount of the m-ZrO2 in the coating is diminished by increasing the concentration of Y(NO3)3 in the electrolyte. This report describes the processing of CMED and studies the microstructure of the deposited YSZ coatings.

  3. Hot Corrosion Behavior of Double-ceramic-layer LaTi2Al9O19/YSZ Thermal Barrier Coatings

    Institute of Scientific and Technical Information of China (English)

    XIE Xiaoyun; GUO Hongbo; GONG Shengkai; XU Huibin

    2012-01-01

    LaTi2Al9O19 (LTA) exhibits promising potential as a new kind of thermal barrier coating (TBC) material,due to its excellent high-temperature capability and low thermal conductivity.In this paper,LTA/yttria stabilized zirconia (YSZ) TBCs are produccd by atmospheric plasma spraying.Hot corrosion behavior and the related failure mechanism of the coating are investigated.Decomposition of LTA does not occur even after 1 458 hot corrosion cycles at 1 373 K,revealing good chemical stability in molten salt of Na2SO4 and NaCl.However,the molten salt infiltrates to the bond coat,causing dissolving of the thermally grown oxide (TGO) in the molten salt and hot corrosion of the bond coat.As a result,cracking of the TBC occurs within the oxide layer.In conclusion,the ceranic materials LTA and YSZ reveal good chemical stability in molten salts of Na2SO4 and NaCl,and the bond coat plays a significant role in providing protection for the component against hot corrosion in the LTA/YSZ TBCs.LTA exhibits very promising potential as a novel TBC material.

  4. Dynamic Changes in LSM Nanoparticles on YSZ: A Model System for Non-stationary SOFC Cathode Behavior

    Energy Technology Data Exchange (ETDEWEB)

    Woo, L Y; Glass, R S; Gorte, R J; Orme, C A; Nelson, A J

    2009-01-05

    The interaction between nanoparticles of strontium-doped lanthanum manganite (LSM) and single crystal yttria-stabilized zirconia (YSZ) was investigated using atomic force microscopy (AFM), x-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM)/energy-dispersive x-ray spectroscopy (EDX). Nanoparticles of LSM were deposited directly onto single crystal YSZ substrates (100) using an ultrasonic spray nozzle. As samples were annealed from 850 C to 1250 C, nanoparticles gradually decreased in height and eventually disappeared completely. Subsequent reduction in H{sub 2}/H{sub 2}O at 700 C resulted in the reappearance of nanoparticles. Studies were carried out on identical regions of the sample allowing the same nanoparticles to be characterized at different temperatures. Morphological changes indicate the formation of a thin layer of LSM, and XPS results support the observation by indicating an increase in signal from the La and Sr and a decrease in signal from the Y and Zr with increasing temperature. SEM/EDX was used to verify that the nanoparticles in the reduced sample contained La. The changes in the LSM/YSZ morphology may be important in explaining the non-stationary behavior observed in operating fuel cells. The thin layer of LSM initially results in poor cathode performance; reducing conditions then lead to film disruptions, indicating nano/microporosity, that increase oxygen ion diffusion and performance.

  5. Aging Studies of Sr-doped LaCrO3/YSZ/Pt Cells for an Electrochemical NOx Sensor

    Energy Technology Data Exchange (ETDEWEB)

    Song, S; Martin, L P; Glass, R S; Murray, E P; Visser, J H; Soltis, R E; Novak, R F; Kubinski, D J

    2005-10-05

    The stability and NO{sub x} sensing performance of electrochemical cells of the structure Sr-doped LaCrO{sub 3-{delta}} (LSC)/yttria-stabilized zirconia (YSZ)/Pt are being investigated for use in NO{sub x} aftertreatment systems in diesel vehicles. Among the requirements for NO{sub x} sensor materials in these systems are stability and long lifetime (up to ten years) in the exhaust environment. In this study, cell aging effects were explored following extended exposure to a test environment of 10% O{sub 2} at operating temperatures of 600-700 C. The data show that aging results in changes in particle morphology, chemical composition and interfacial structure, Impedance spectroscopy indicated an initial increase in the cell resistance during the early stages of aging, which is correlated to densification of the Pt electrode. Also, x-ray photoelectron spectroscopy indicated formation of SrZrO{sub 2} solid state reaction product in the LSC, a process which is of finite duration. Subsequently, the overall cell resistance decreases with aging time due, in part, to roughening of YSZ-LSC interface, which improves interface adherence and enhances charge transfer kinetics at the O{sub 2}/YSZ/LSC triple phase boundary. This study constitutes a first step in the development of a basic understanding of aging phenomena in solid state electrochemical systems with application not only to sensors, but also to fuel cells, membranes, and electrolyzers.

  6. Density functional theory study of the interaction of H2O, CO2 and CO with the ZrO2 (111), Ni/ZrO2 (111), YSZ (111) and Ni/YSZ (111) surfaces

    Science.gov (United States)

    Cadi-Essadek, Abdelaziz; Roldan, Alberto; de Leeuw, Nora H.

    2016-11-01

    The triple phase boundary (TPB), where the gas phase, Ni particles and the yttria-stabilised zirconia (YSZ) surface meet, plays a significant role in the performance of solid oxide fuel cells (SOFC). Indeed, the key reactions take place at the TPB, where molecules such as H2O, CO2 and CO interact and react. We have systematically studied the interaction of H2O, CO2 and CO with the dominant surfaces of four materials that are relevant to SOFC, i.e. ZrO2(111), Ni/ZrO2(111), YSZ(111) and Ni/YSZ(111) of cubic ZrO2 stabilized with 9% of yttria (Y2O3). The study employed spin polarized density functional theory (DFT), taking into account the long-range dispersion forces. We have investigated up to five initial adsorption sites for the three molecules and have identified the geometries and electronic structures of the most stable adsorption configurations. We have also analysed the vibrational modes of the three molecules in the gas phase and compared them with the adsorbed molecules. A decrease of the wavenumbers of the vibrational modes for the three adsorbed molecules was observed, confirming the influence of the surface on the molecules' intra-molecular bonds. These results are in line with the important role of Ni in this system, in particular for the CO adsorption and activation. This document contains the binding energies at the non-equivalent adsorption sites for H2O, CO2 and CO molecules on ZrO2(111) (Figure S1 and Table S1), Ni/ZrO2(111) (Figure S2 and Table S2), YSZ(111) (Figure S3 and Table S3) and Ni/YSZ(111) (Figure S4 and Table S4). We have not reported here the zero point energy. This document also contains the ZrxOyHz clusters studied in Ref. 40 and discussed in our manuscript (Figure S5).

  7. Application of advanced morphology Au–X (X = YSZ, ZrO2) composites as sensing electrode for solid state mixed-potential exhaust NOx sensor

    OpenAIRE

    Romanytsia, Ivan; Viricelle, Jean-Paul; Vernoux, Philippe; Pijolat, C.

    2015-01-01

    SSCI-VIDE+CARE+PVE; International audience; Among various NOx sensors developments, mixed potential sensor based on Yttria Stabilized Zirconia (YSZ) with a simple planar architecture Au/YSZ/Pt is of practical interest. Au composites electrodes were investigated to improve sensing performances. Such potentiometric solid-state gas sensors – were fabricated by screen-printing and tested for NO2 detection. Electrochemical impedance spectroscopy has shown that the addition of YSZ in the Au electro...

  8. Characteristics of selected thermal properties of 8YSZ type powders produced with different methods

    Energy Technology Data Exchange (ETDEWEB)

    Moskal, G, E-mail: grzegorz.moskal@polsl.pl [Silesian University of Technology, Department of Materials Science, 40-019 Katowice, 8 Krasinskiego (Poland)

    2010-11-15

    The paper presents test results concerning characteristics of the selected thermal properties of ceramic powders of 8YSZ type on the basis of zirconium oxide modified with yttrium oxide obtained with different methods. The first of the powders was obtained with the spray drying method, the second one was characterized by a structure typical for obtaining methods from liquid phase and the third of the powders was obtained with the grinding method to get maximally broken up powder particles and similar to 'nano' type structures. The scope of the tests encompassed thermal diffusivity analysis of the powders in a compressed form within temperature range 25-1500 deg. C, and also tests of specific heat within similar temperature range. Specific heat measurements of the powders showed that the highest values within the entire test temperature range were obtained for the finest grain ('nano-sized') powder. In other two cases, the values obtained were very similar. Analogous results were found in the case of thermal diffusivity measurements. The ground powder was characterized by significantly lower thermal diffusivity value than other two types of powders, which was a result of very strong break-up of particles.

  9. Characteristics of selected thermal properties of 8YSZ type powders produced with different methods

    Science.gov (United States)

    Moskal, G.

    2010-11-01

    The paper presents test results concerning characteristics of the selected thermal properties of ceramic powders of 8YSZ type on the basis of zirconium oxide modified with yttrium oxide obtained with different methods. The first of the powders was obtained with the spray drying method, the second one was characterized by a structure typical for obtaining methods from liquid phase and the third of the powders was obtained with the grinding method to get maximally broken up powder particles and similar to "nano" type structures. The scope of the tests encompassed thermal diffusivity analysis of the powders in a compressed form within temperature range 25-1500°C, and also tests of specific heat within similar temperature range. Specific heat measurements of the powders showed that the highest values within the entire test temperature range were obtained for the finest grain ("nano-sized") powder. In other two cases, the values obtained were very similar. Analogous results were found in the case of thermal diffusivity measurements. The ground powder was characterized by significantly lower thermal diffusivity value than other two types of powders, which was a result of very strong break-up of particles.

  10. Conductivity and structure of sub-micrometric SrTiO3-YSZ composites

    DEFF Research Database (Denmark)

    Ruiz Trejo, Enrique; Thydén, Karl Tor Sune; Bonanos, Nikolaos;

    2016-01-01

    Sub-micrometric composites of SrTiO3-YSZ (1:1 volume) and samples of SrTiO3 were prepared by high temperature consolidation of precursors obtained by precipitation with NaOH. The structure development and morphology of the precursors were studied by XRD and SEM. The perovskite and fluorite phases...... in the composites are clearly formed at 600°C with no signs of reaction up to 1100°C; the nominally pure SrTiO3 can be formed at temperatures as low as 400°C. Composites with sub-micrometric grain sizes can be prepared successfully without reaction between the components, although a change in the cell parameter...... of the SrTiO3 is attributed to the presence of Na. The consolidated composites were studied by impedance spectroscopy between 200 and 400°C and at a fixed temperature of 600°C with a scan in the partial pressure of oxygen. The composites did not exhibit high levels of ionic conductivity in the grain...

  11. Role of dispersion conditions on grindability of yttria stabilized zirconia (YSZ) powders

    Indian Academy of Sciences (India)

    S Ramanathan; K P Krishna Kumar; P K De; S Banerjee

    2005-04-01

    A precursor for zirconia – 8 mole% yttria (YSZ–ZrO2–8 m% Y2O3) powder was prepared by coprecipitation and the calcination temperature was fixed as 900°C from TG–DTA and XRD studies. The calcined powder could be dry ground only to a mean particle size (50) of 6 m containing substantial amount of coarse agglomerates in the size range 10–100 m. The dispersion conditions for its wet grinding were evaluated through zeta-potential and viscosity studies. The zeta-potential variation with pH of the aqueous suspensions of the powder exhibited maximum numerical values at 3 and 11 pH, exhibiting the ideal pHs for dispersion stability through electrostatic columbic repulsion mechanism. Slurries of dry ground powders with solid concentration in the range 15–30 vol.% exhibited pseudo-plastic flow characteristics, indicating presence of flocculates. With progress of grinding, the increase in viscosity of the slurries became less significant with decreasing solid concentration. Even though the particle size of the ground slurries decreased with decreasing solid content, there was little change in it for slurries with solid content < 20 vol.%. Grinding conditions for formation of sinter-active powders of YSZ with sub-micron size (50\\ ∼ 0.7 m free of agglomerates of size > 5 m) were established. Compacts from this powder could be sintered at 1400°C to translucent bodies with 99% theoretical density.

  12. Advanced study of thermal behaviour of CSZ comparing with the classic YSZ coating

    Science.gov (United States)

    Dragomirescu, A.; Constantin, N.; Ştefan, A.; Manoliu, V.; Truşcă, R.

    2017-01-01

    Thermal barrier coatings (TBC) are advanced materials typically applied to metal surfaces subjected to extreme temperatures to protect them and increase their lifetime. Ceria stabilized zirconia ceramic layer (CSZ) is increasingly used as an alternative improved as replace for classical TBC system - yttria stabilized zirconia - thanks to superior properties, including mechanical and high resistance to thermal corrosion. The paper describes the thermal shock testing of two types of thermal barrier coatings used to protect a nickel super alloy. For the experimental procedure, it was used plate samples from nickel super alloy with a bond coat and a ceramic top coat. The top coat was different: on some samples, it was used YSZ and on others CSZ. Ni based super alloys have good corrosion resistance in reducing environments action, but poor in oxidizing conditions. Extreme environments can lead to loss of material by oxidation / corrosion, along with decreased mechanical properties of the substrate due to damaging elements which diffuses into the substrate at high temperatures. Using laboratory equipment, the TBC systems were exposed repeatedly to extreme high temperatures for a short time and then cooled. After the thermal shock tests, the samples were morph-structured characterized using electronic microscopy to analyze the changes. The experimental results were compared to rank the TBC systems in order of performance.

  13. Tropical cyclones over NIO during La-Nina Modoki years

    Digital Repository Service at National Institute of Oceanography (India)

    Sumesh, K.G.; RameshKumar, M.R.

    Tropical cyclones over NIO (North Indian Ocean) are highly influenced by the El-Nino and La-Nina activities over the Pacific Ocean Influences of air-sea interaction processes like El-Nino Modoki and La-Nina Modoki on tropical cyclones are less...

  14. SYNTHESIS OF NiO NANOPARTICLES IN ETHYLENE GLYCOL

    Institute of Scientific and Technical Information of China (English)

    Desheng Ai; Xiaming Dai; Qingfeng Li; Changsheng Deng; Shinhoo Kang

    2004-01-01

    NiO nanoparticles with well-dispersed property were prepared via a wet chemical method in ethylene glycol (EG) without soluble polymer as a protective agent. The mechanism of chemical process was proposed based on color change during the experiment. The dispersion function of EG was discussed.

  15. Electronic structure of NiO: Correlation and band effects

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Z. (Stanford Electronics Laboratory, Stanford University, Stanford, California (USA)); List, R.S. (Los Alamos National Laboratory, Los Alamos, New Mexico (USA)); Dessau, D.S.; Wells, B.O. (Stanford Electronics Laboratory, Stanford University, Stanford, California (USA)); Jepsen, O. (Max-Planck-Institute for Solid State Research, D-7000 Stuttgart 80 (Federal Republic of Germany)); Arko, A.J.; Barttlet, R. (Los Alamos National Laboratory, Los Alamos, New Mexico (USA)); Shih, C.K. (Department of Physics, University of Texas, Austin, Texas (USA)); Parmigiani, F. (IBM Research Division, Almaden Research Center, 650 Harry Road, San Jose, California (USA)); Huang, J.C.; Lindberg, P.A.P. (Stanford Electronics Laboratory, Stanford University, Stanford, California (USA))

    1991-08-15

    We have performed angle-resolved-photoemission experiments and local-density-functional (LDA) band calculations on NiO to study correlation and band effects of this conceptually important compound. Our experimental result suggests a dual nature of the electronic structure of NiO. On the one hand, the LDA band calculation has some relevance to the electronic structure of NiO, and the inclusion of the antiferromagnetic order is essential. For the lower O 2{ital p} bands, the LDA calculation agrees almost perfectly with experimental energy positions and dispersion relations. On the other hand, discrepancies between the experiment and the LDA calculation do exist, especially for the Ni 3{ital d} bands and the O 2{ital p} bands that are heavily mixed with the Ni 3{ital d} bands. It appears that the main discrepancies between the experimental results and the LDA calculation are concentrated in the regions of the insulating gap and the valence-band satellite. In addition to these results, we also report the interesting angle and photon-energy dependence of the satellite emission. The above results show that the angle-resolved-photoemission studies can provide much additional information about the electronic structure of correlated materials like NiO.

  16. Study of synthesis routes and processing of NiO-YSZ ceramic composite for use as anode in solid oxide fuel cell (SOFC); Estudo de rotas de sintese e processamento ceramico do composito NiO-YSZ para aplicacao como anodo em celulas a combustivel do tipo oxido solido (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Yoshito, Walter Kenji

    2011-07-01

    This study aim the definition of synthesis and ceramic processing conditions of the anodic component suitable for operation of SOFC, i.e, homogeneous distribution of NiO in YSZ matrix and porosity after reduction above 30%. The selected synthesis routes included the co-precipitation in ammonia media, mechanical mixing of powders and combustion reaction from nitrate salts. The characterization techniques of powders included the X-ray diffraction, scanning and transmission electron microscopy, laser diffraction, nitrogen gas adsorption technique (BET) and Helium pycnometry. The obtained results indicated that the loss of Ni{sup 2+} in co-precipitation process, due to the formation of complex [Ni(NH{sub 3}){sub n}]{sup 2+}, can be minimized by controlling the pH around 9.3, keeping the concentration of nickel cation in the solution to be precipitated around 0.1M. In the mechanical mixing method the best condition of powder dispersion, without differential sedimentation, was obtained for zeta potential values at pH around 8.0, fixing the dispersant concentration at 0.8%. For the combustion synthesis it was observed that when stoichiometric and twofold stoichiometric urea was used, amorphous phase was formed and a higher surface area was attained in the final products. Employing the fuel-rich solution condition, crystallization of the powder was observed and the relative intensity of reflections of XRD patterns increased with excess of fuel, due to increasing the reaction temperature. Sinterability studies of pellets prepared from powder synthesized by the three routes described above showed the temperature around 1300 deg C for maximum rate densification and porosity between 6.0 and 14%. Reduction results of the composites confirmed that the reduction kinetics occurs in two steps. The first one with a linear behavior and controlled by chemical reaction on the surface. The second reduction step is the reduction that is controlled by gas diffusion in micro pores

  17. The effect of size on the resistive switching characteristics of NiO nanodots

    Science.gov (United States)

    Ahn, Yoonho; Son, Jong Yeog

    2016-12-01

    NiO nanodots were fabricated via a shattering process using an AFM tip, where an NiO nanodot with a diameter of approximately 90 nm was broken into very small pieces. The pieces showed diverse diameters, including three diameters of approximately 10, 20, and 30 nm. The NiO nanodots exhibited unipolar switching characteristics including bistable resistivity during 200 repeated switching cycles. Significantly, the magnitude of the "ON currents" was observed to depend on the formation of conducting filaments in the NiO nanodots. We suggest that the critical diameter of the RRAM NiO nanodots is approximately 30 nm.

  18. An ultra-high vacuum electrochemical flow cell for in situ/operando soft X-ray spectroscopy study

    Energy Technology Data Exchange (ETDEWEB)

    Bora, Debajeet K., E-mail: debajeet.bora@empa.ch, E-mail: jguo@lbl.gov; Glans, Per-Anders; Pepper, John; Liu, Yi-Sheng; Guo, J.-H., E-mail: debajeet.bora@empa.ch, E-mail: jguo@lbl.gov [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Du, Chun; Wang, Dunwei [Department of Chemistry, Boston College, Boston, Massachusetts 02467 (United States)

    2014-04-15

    An in situ flow electrochemical cell has been designed and fabricated to allow better seal under UHV chamber thus to achieve a good signal to noise ratio in fluorescence yield detection of X-ray absorption spectra for spectroelectrochemical study. The cell also stabilizes the thin silicon nitride membrane window in an effective manner so that the liquid cell remains intact during X-ray absorption experiments. With the improved design of the liquid cell, electrochemical experiments such as cyclic voltammetry have been performed for 10 cycles with a good stability of sample window. Also an operando electrochemical experiment during photoelectrochemistry has been performed on n-type hematite electrode deposited on silicon nitride window. The experiment allows us to observe the formation of two extra electronic transitions before pre edge of O K-edge spectra.

  19. Operando NMR and XRD study of chemically synthesized LiCx oxidation in a dry room environment

    Science.gov (United States)

    Sacci, Robert L.; Gill, Lance W.; Hagaman, Edward W.; Dudney, Nancy J.

    2015-08-01

    We test the stability of pre-lithiated graphite anodes for Li-ion batteries in a dry room battery processing room. The reaction between LiCx and laboratory air was followed using operando NMR and x-ray diffraction, as these methods are sensitive to change in Li stoichiometry in graphite. There is minimal reactivity between LiC6 and N2, CO2 or O2; however, LiC6 reacts with moisture to form lithium (hydr)oxide. The reaction rate follows zero-order kinetics with respects to intercalated lithium suggesting that lithium transport through the graphite is fast. The reaction occurs by sequential formation of higher stages-LiC12, then LiC18, and then LiC24-as the hydrolysis proceeds to the formation of LixOHy and graphite end products. Slowing down the formation rate of the LixOHy passivation layer stabilizes of the higher stages.

  20. Does Pelletizing Catalysts Influence the Efficiency Number of Activity Measurements? Spectrochemical Engineering Considerations for an Accurate Operando Study

    DEFF Research Database (Denmark)

    Rasmussen, Søren Birk; Perez-Ferreras, Susana; Banares, Miguel A.

    2013-01-01

    of, for example, support oxides might take place, which in turn affects the pore size distribution and the porosity of the catalyst, leading to the observation of lower activity values due to decreased catalyst efficiency. This phenomenon can also apply to conventional activity measurements......, in the cases that pelletizing and recrushing of samples are performed to obtain adequate particle size fractions for the catalytic bed. A case study of an operand investigation of a V2O3-WO3/TiO2-sepiolite catalyst is used as an example, and simple calculations of the influence of catalyst activity...... and internal pore diffusion properties are considered in this paper for the evaluation of catalyst performance in, for example, operando reactors. Thus, it is demonstrated that with a pelletizing pressure of...

  1. A versatile salt evaporation reactor system for SOFC operando studies on anode contamination and degradation with impedance spectroscopy

    Science.gov (United States)

    Nurk, Gunnar; Holtappels, Peter; Figi, Renato; Wochele, Jörg; Wellinger, Marco; Braun, Artur; Graule, Thomas

    2011-03-01

    The dependence of the degradation kinetics in Ni-CGO (cerium-gadolinium oxide) solid oxide fuel cell (SOFC) anodes upon salt evaporation is demonstrated operando with a custom built versatile reactor system. The system is based on evaporation and subsequent condensation of low concentration salt vapor aerosol mixtures representative of salt vapors typically present in biomass gasification processes. Fast changes in the charge transfer and ohmic resistance are observed in the anodes fuelled with a gas mixture containing a high KCl vapor concentration. Rapid condensation of salt vapors into the porous anode and partial delamination of the anode from the electrolyte surface because of salt deposits inside the porous anode is observed. The flexibility to produce vapor-aerosol mixtures with different concentrations and particle size distributions is proved, and suitability of these aerosols for anode testing in long term fuel cell test is evaluated.

  2. A versatile LabVIEW and FPGA-based scanned probe microscope for in-operando electronic device characterization

    CERN Document Server

    Berger, Andrew J; Jacob, Jan; Young, Justin R; Lewis, Jim; Wenzel, Lothar; Bhallamudi, Vidya P; Johnston-Halperin, Ezekiel; Pelekhov, Denis V; Hammel, P Chris

    2014-01-01

    Understanding the complex properties of electronic and spintronic devices at the micro- and nano-scale is a topic of intense current interest as it becomes increasingly important for scientific progress and technological applications. In-operando characterization of such devices by scanned probe techniques is particularly well-suited for the microscopic study of these properties. We have developed a scanned probe microscope (SPM) which is capable of both standard force imaging (atomic, magnetic, electrostatic) and simultaneous electrical transport measurements. We utilize flexible and inexpensive FPGA (field programmable gate array) hardware and a custom software framework developed in National Instrument's LabVIEW environment to perform the various aspects of microscope operation and device measurement. The FPGA-based approach enables sensitive, real-time cantilever frequency-shift detection. Using this system, we demonstrate electrostatic force microscopy of an electrically-biased graphene FET device. The c...

  3. Operando studies of all-vanadium flow batteries: Easy-to-make reference electrode based on silver-silver sulfate

    Science.gov (United States)

    Ventosa, Edgar; Skoumal, Marcel; Vázquez, Francisco Javier; Flox, Cristina; Morante, Joan Ramon

    2014-12-01

    In-depth evaluation of the electrochemical performance of all-vanadium redox flow batteries (VRFBs) under operando conditions requires the insertion of a reliable reference electrode in the battery cell. In this work, an easy-to-make reference electrode based on silver-silver sulfate is proposed and described for VRFBs. The relevance and feasibility of the information obtained by inserting the reference electrode is illustrated with the study of ammoxidized graphite felts. In this case, we show that the kinetic of the electrochemical reaction VO2+/VO2+ is slower than that of V2+/V3+ at the electrode. While the slow kinetics at the positive electrode limits the voltage efficiency, the operating potential of the negative electrode, which is outside the stability widow of water, reduces the coulombic efficiency due to the hydrogen evolution.

  4. Hot corrosion behavior of nanostructured Gd2O3 doped YSZ thermal barrier coating in presence of Na2SO4 + V2O5 molten salts

    Directory of Open Access Journals (Sweden)

    Yixiong Wang

    2017-08-01

    Full Text Available Nickel-based superalloy DZ125 was first sprayed with a NiCrAlY bond coat and followed with a nanostructured 2 mol% Gd2O3−4.5 mol% Y2O3-ZrO2 (2GdYSZ topcoat using air plasma spraying (APS. Hot corrosion behavior of the as-sprayed thermal barrier coatings (TBCs were investigated in the presence of 50 wt% Na2SO4 + 50 wt% V2O5 as the corrosive molten salt at 900 °C for 100 h. The analysis results indicate that Gd doped YVO4 and m-ZrO2 crystals were formed as corrosion products due to the reaction of the corrosive salts with stabilizers (Y2O3, Gd2O3 of zirconia. Cross-section morphology shows that a thin layer called TGO was formed at the bond coat/topcoat interface. After hot corrosion test, the proportion of m-ZrO2 phase in nanostructured 2GdYSZ coating is lower than that of nano-YSZ coating. The result reveals that nanostructured 2GdYSZ coating exhibits a better hot corrosion resistance than nano-YSZ coating.

  5. Enhanced Sintering of β"-Al2O3/YSZ with the Sintering Aids of TiO2 and MnO2

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Xiaochuan; Li, Guosheng; Kim, Jin Yong; Meinhardt, Kerry D.; Sprenkle, Vincent L.

    2015-07-11

    β"-Al2O3 has been the dominated choice for the electrolyte materials of sodium batteries because of its high ionic conductivity, excellent stability with the electrode materials, satisfactory mechanical strength, and low material cost. To achieve adequate electrical and mechanical performance, sintering of β"-Al2O3 is typically carried out at temperatures above 1600oC with deliberate efforts on controlling the phase, composition, and microstructure. Here, we reported a simple method to fabricate β"-Al2O3/YSZ electrolyte at relatively lower temperatures. With the starting material of boehmite, single phase of β"-Al2O3 can be achieved at as low as 1200oC. It was found that TiO2 was extremely effective as a sintering aid for the densification of β"-Al2O3 and similar behavior was observed with MnO2 for YSZ. With the addition of 2 mol% TiO2 and 5 mol% MnO2, the β"-Al2O3/YSZ composite was able to be densified at as low as 1400oC with a fine microstructure and good electrical/mechanical performance. This study demonstrated a new approach of synthesis and sintering of β"-Al2O3/YSZ composite, which represented a simple and low-cost method for fabrication of high-performance β"-Al2O3/YSZ electrolyte.

  6. Quantification of Electrochemical Nanoscale Processes in Lithium Batteries By OperandoEC-(S)TEM

    Energy Technology Data Exchange (ETDEWEB)

    Mehdi, Beata L.; Qian, Jiangfeng; Nasybulin, Eduard; Welch, David A.; Park, Chiwoo; Faller, Roland; Mehta, Hardeep S.; Henderson, Wesley A.; Xu, Wu; Evans, James E.; Liu, Jun; Zhang, Jiguang; Mueller, Karl T.; Browning, Nigel D.

    2015-07-27

    Lithium (Li)-ion batteries are currently used for a wide variety of portable electronic devices, electric vehicles and renewable energy applications. In addition, extensive worldwide research efforts are now being devoted to more advanced “beyond Li-ion” battery chemistries - such as lithium-sulfur (Li-S) and lithium-air (Li-O2) - in which the carbon anode is replaced with Li metal. However, the practical application of Li metal anode systems has been highly problematic. The main challenges involve controlling the formation of a solid-electrolyte interphase (SEI) layer and the suppression of Li dendrite growth during the charge/discharge process (achieving “dendrite-free” cycling). The SEI layer formation continuously consumes the electrolyte components creating highly resistive layer, which leads to the rapid decrease of cycling performance and degradation of the Li anode. The growth of Li metal dendrites at the anode contributes to rapid capacity fading (the presence of “dead Li” created during the discharge leads to an increased overpotential) and, in the case of continuous growth, leads to internal short circuits and extreme safety issues. Here we demonstrate the application of an operando electrochemical scanning transmission electron microscopy (ec-(S)TEM) cell to study the SEI layer formation and the initial stages of Li dendrite growth - the goal is to develop a mechanism for mitigating the degradation processes and increasing safety. Bright field (BF) STEM images in Figure 1 A-C show Li metal deposition and dissolution processes at the interface between the Pt working electrode and the lithium hexafluorophosphate (LiPF6) in propylene carbonate (PC) electrolyte during three charge/discharge cycles. A contrast reversal caused by Li metal being lighter/less dense than surrounding electrolyte (Li appears brighter than the background in BF STEM images) allows Li to be uniquely identified from the other components in the system - the only solid

  7. An Analysis of Biogas Reforming Process on Ni/YSZ and Ni/SDC Catalysts

    Directory of Open Access Journals (Sweden)

    Janusz Szmyd

    2012-02-01

    Full Text Available The conversion of biogas to electricity presents an attractive niche application for fuel cells. Thus attempts have been made to use biogas as a fuel for high temperature fuel cell systems such as SOFC. Biogas can be converted to hydrogen-rich fuel in a reforming process. For hydrocarbon-based fuel, three types of fuel conversion can be considered in reforming reactions: an external reforming system, an indirect internal reforming system and a direct internal reforming system. High-temperature SOFC eliminates the need for an expensive external reforming system. The possibility of using internal reforming is one of the characteristics of high temperature fuel cells like SOFC. However, for high-temperature operation, thermal management of the SOFC system becomes an important issue. To properly carry out thermal management, both detailed modeling and numerical analyses of the phenomena occurring inside the SOFC system is required. In the present work, the process of reforming biogas on a Ni/YSZ and a Ni/SDC catalyst has been numerically and experimentally investigated. Measurements including different thermal boundary conditions, steam-to-carbon ratios and several different fuel compositions were taken. A numerical model containing methane/steam reforming reaction, dry reforming reaction and shift reaction has been proposed to predict the gas mixture composition at the outlet of the reformer. The results of the numerical computation were compared with experimental data and good agreement has been found. The results indicate the importance of combined, numerical and experimental studies in the design of SOFC reformers. The combined approach used leads to the successful prediction of the outlet gas composition for different modelling conditions.

  8. Investigating lithium-ion battery materials during overcharge-induced thermal runaway: an operando and multi-scale X-ray CT study.

    Science.gov (United States)

    Finegan, Donal P; Scheel, Mario; Robinson, James B; Tjaden, Bernhard; Di Michiel, Marco; Hinds, Gareth; Brett, Dan J L; Shearing, Paul R

    2016-11-16

    Catastrophic failure of lithium-ion batteries occurs across multiple length scales and over very short time periods. A combination of high-speed operando tomography, thermal imaging and electrochemical measurements is used to probe the degradation mechanisms leading up to overcharge-induced thermal runaway of a LiCoO2 pouch cell, through its interrelated dynamic structural, thermal and electrical responses. Failure mechanisms across multiple length scales are explored using a post-mortem multi-scale tomography approach, revealing significant morphological and phase changes in the LiCoO2 electrode microstructure and location dependent degradation. This combined operando and multi-scale X-ray computed tomography (CT) technique is demonstrated as a comprehensive approach to understanding battery degradation and failure.

  9. Development of an Innovative XRD-DRIFTS Prototype Allowing Operando Characterizations during Fischer-Tropsch Synthesis over Cobalt-Based Catalysts under Representative Conditions

    Directory of Open Access Journals (Sweden)

    Scalbert Julien

    2015-03-01

    Full Text Available An original system combining both X-Ray Diffraction and diffuse reflectance infrared Fourier transform spectroscopy was developed with the aim to characterize Fischer-Tropsch catalysts in relevant reaction conditions. The catalytic properties of a model PtCo/silica catalyst tested with this prototype have shown to be in the same range of those obtained in similar conditions with classical fixed-bed reactors. No bulk cobalt oxidation nor sintering were observed on operando XRD patterns. The formation of linear carbonyls and adsorbed hydrocarbons species at the surface of the catalyst was observed on operando DRIFT spectra. The surface of the catalyst was also suspected to be covered with carbon species inducing unfavorable changes in selectivity.

  10. In operando study of high-performance thermoelectric materials for power generation: a case study of β-Zn4Sb3

    DEFF Research Database (Denmark)

    Ngo, Duc-The; Han, Li; Iversen, Bo Brummerstedt

    2017-01-01

    To date, many high-performancethermoelectric (TE) materials for power generation have been studied and reported. However, so far they have not been implementedin reliable commercial devices. To bring currentachievements into a device for power generation, a full understanding thedynamic behavior...... of thermoelectricmaterials under operating conditions is needed. In this work, an in operando study isconducted on the high-performance TEmaterial β-Zn4Sb3under large temperature gradient and thermal cycling by a new approachusing in-situ transmission electronmicroscopy combined with characterization of the TE properties...... on the cold side of the β-Zn4Sb3 leg. The dynamical evolution of Zn in the matrix of β-Zn4Sb3 was found to be the source thatleads to a high zT value by loweringof the thermal conductivity and electrical resistivity, but it is also the failuremechanism for the leg under these conditions. The in operando study...

  11. Deconvolution of X-ray diffraction profiles using series expansion: a line-broadening study of polycrystalline 9-YSZ

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Bajo, F. [Universidad de Extremadura, Badajoz (Spain). Dept. de Electronica e Ingenieria Electromecanica; Ortiz, A.L.; Cumbrera, F.L. [Universidad de Extremadura, Badajoz (Spain). Dept. de Fisica

    2001-07-01

    Deconvolution of X-ray diffraction profiles is a fundamental step in obtaining reliable results in the microstructural characterization (crystallite size, lattice microstrain, etc) of polycrystalline materials. In this work we have analyzed a powder sample of 9-YSZ using a technique based on the Fourier series expansion of the pure profile. This procedure, which can be combined with regularization methods, is specially powerful to minimize the effects of the ill-posed nature of the linear integral equation involved in the kinematical theory of X-ray diffraction. Finally, the deconvoluted profiles have been used to obtain microstructural parameters by means of the integral-breadth method. (orig.)

  12. Steady state creep of Ni-8YSZ substrates for application in solid oxide fuel and electrolysis cells

    Science.gov (United States)

    Wei, J.; Malzbender, J.

    2017-08-01

    Steady state creep was characterized for Ni-8YSZ solid oxide fuel/electrolysis cell (SOFC/SOEC) substrate material. Intrinsic and extrinsic factors affecting creep behavior were assessed, such as compositional ratio, porosity and mechanical loading configuration. Mechanical tests were supported by analytical and numerical calculations. The results indicated a diffusion-dominated creep mechanism under both compressive and tensile creep conditions. Creep appeared to be dominated by the ceramic phase. Porosity significantly reduced creep resistance. The activation energy was discussed based on loading configuration, temperature and porosity.

  13. Three-dimensional microstructural imaging of sulfur poisoning-induced degradation in a Ni-YSZ anode of solid oxide fuel cells.

    Science.gov (United States)

    Harris, William M; Lombardo, Jeffrey J; Nelson, George J; Lai, Barry; Wang, Steve; Vila-Comamala, Joan; Liu, Mingfei; Liu, Meilin; Chiu, Wilson K S

    2014-06-10

    Following exposure to ppm-level hydrogen sulfide at elevated temperatures, a section of a solid oxide fuel cell (SOFC) Ni-YSZ anode was examined using a combination of synchrotron-based x-ray nanotomography and x-ray fluorescence techniques. While fluorescence measurements provided elemental identification and coarse spatial mapping, x-ray nanotomography was used to map the detailed 3-D spatial distribution of Ni, YSZ, and a nickel-sulfur poisoning phase. The nickel-sulfur layer was found to form a scale covering most of the exposed nickel surface, blocking most fuel reformation and hydrogen oxidation reaction sites. Although the exposure conditions precluded the ability to develop a detailed kinetic description of the nickel-sulfur phase formation, the results provide strong evidence of the detrimental effects of 100 ppm hydrogen sulfide on typical Ni-YSZ anode materials.

  14. Three-Dimensional Microstructural Imaging of Sulfur Poisoning-Induced Degradation in a Ni-YSZ Anode of Solid Oxide Fuel Cells

    Science.gov (United States)

    Harris, William M.; Lombardo, Jeffrey J.; Nelson, George J.; Lai, Barry; Wang, Steve; Vila-Comamala, Joan; Liu, Mingfei; Liu, Meilin; Chiu, Wilson K. S.

    2014-06-01

    Following exposure to ppm-level hydrogen sulfide at elevated temperatures, a section of a solid oxide fuel cell (SOFC) Ni-YSZ anode was examined using a combination of synchrotron-based x-ray nanotomography and x-ray fluorescence techniques. While fluorescence measurements provided elemental identification and coarse spatial mapping, x-ray nanotomography was used to map the detailed 3-D spatial distribution of Ni, YSZ, and a nickel-sulfur poisoning phase. The nickel-sulfur layer was found to form a scale covering most of the exposed nickel surface, blocking most fuel reformation and hydrogen oxidation reaction sites. Although the exposure conditions precluded the ability to develop a detailed kinetic description of the nickel-sulfur phase formation, the results provide strong evidence of the detrimental effects of 100 ppm hydrogen sulfide on typical Ni-YSZ anode materials.

  15. Effect of Buffer Layer on Epitaxial Growth of YSZ Deposited on Si Substrate by Slower Q-switched 266 nm YAG Laser

    Science.gov (United States)

    Kaneko, Satoru; Akiyama, Kensuke; Shimizu, Yoshitada; Ito, Takeshi; Yasaka, Shinji; Mitsuhashi, Masahiko; Ohya, Seishiro; Saito, Keisuke; Watanabe, Takayuki; Okamoto, Shoji; Funakubo, Hiroshi

    2004-04-01

    Yttria-stabilized zirconia (YSZ) was grown on Si(100) substrate by pulsed laser deposition (PLD). The laser used in this study was a 266 nm YAG laser with a second function generator modulating only the Q-switch while the primary generator modulated the flash lamp (slower Q-switch). Epitaxial growth was verified on YSZ film deposited without oxygen gas followed by primary deposition in oxygen atmosphere on Si substrate with a ˜0.4-nm-thin oxide layer. The crystallinity was strongly dependent on the thickness of the buffer layer deposited prior to the primary deposition of YSZ. The epitaxial growth was confirmed by φ scan, and ω scan (rocking curve) showed the full width at half maximum (FWHM) of 1.1 deg. The required oxygen pressure for epitaxial growth was quite high compared to that of excimer deposition.

  16. Electrochromic NiO thin films prepared by spin coating

    Science.gov (United States)

    Özütok, F.; Demiri, S.; Özbek, E.

    2017-02-01

    Recently, smart windows are very important because they are often being used in smart buildings and car glasses (windows). At this point, producing effective electrochromic materials is so necessary. In this study, we produced NiO thin films by using spin coating technique on In-doped SnO2 (ITO) substrate. Nickel proportions of these nickel oxide (NiO) films are 3, 5 and 7 %. Nickel acetate tetrahydrate is the initial solution and solvents are ethylene gl ycol and n-hexzane. Structural properties and surface images are investigated by using x-ray diffactometer (XRD) and scanning electron microscope (SEM) device, respectively. In addition, electrochemical behavior is investigated by cyclic voltammetry. A correlation between surface morphology and electrochromic performance was observed as well.

  17. p-Type NiO Hybrid Visible Photodetector.

    Science.gov (United States)

    Mallows, John; Planells, Miquel; Thakare, Vishal; Bhosale, Reshma; Ogale, Satishchandra; Robertson, Neil

    2015-12-23

    A novel hybrid visible-light photodetector was created using a planar p-type inorganic NiO layer in a junction with an organic electron acceptor layer. The effect of different oxygen pressures on formation of the NiO layer by pulsed laser deposition shows that higher pressure increases the charge carrier density of the film and lowers the dark current in the device. The addition of a monolayer of small molecules containing conjugated π systems and carboxyl groups at the device interface was also investigated and with correct alignment of the energy levels improves the device performance with respect to the quantum efficiency, responsivity, and photogeneration. The thickness of the organic layer was also optimized for the device, giving a responsivity of 1.54 × 10(-2) A W(-1) in 460 nm light.

  18. O Património Cultural da Freguesia da Cumieira

    OpenAIRE

    Silva, José Emílio Esteves da

    2010-01-01

    Dissertação de Mestrado em Ciências da Cultura O património cultural, material e imaterial, caracteriza e identifica uma comunidade através dos tempos. A freguesia da Cumieira, concelho de Santa Marta de Penaguião, possui, na sua área, um vasto património constituído por achados arqueológicos e edificações e por um conjunto de saberes ancestrais, ainda utilizados no seu quotidiano, que faz a história do seu povo. Exemplos dessa riqueza são os indícios de povoamento romano e mouro, a igreja...

  19. Growth mechanism and magnon excitation in NiO nanowalls

    Directory of Open Access Journals (Sweden)

    Yang Chun

    2011-01-01

    Full Text Available Abstract The nanosized effects of short-range multimagnon excitation behavior and short-circuit diffusion in NiO nanowalls synthesized using the Ni grid thermal treatment method were observed. The energy dispersive spectroscopy mapping technique was used to characterize the growth mechanism, and confocal Raman scattering was used to probe the antiferromagnetic exchange energy J 2 between next-nearest-neighboring Ni ions in NiO nanowalls at various growth temperatures below the Neel temperature. This study shows that short spin correlation leads to an exponential dependence of the growth temperatures and the existence of nickel vacancies during the magnon excitation. Four-magnon configurations were determined from the scattering factor, revealing a lowest state and monotonic change with the growth temperature. PACS: 75.47.Lx; 61.82.Rx; 75.50.Tt; 74.25.nd; 72.10.Di

  20. An operando optical fiber UV–vis spectroscopic study of the catalytic decomposition of NO and N2O over Cu-ZSM-5

    NARCIS (Netherlands)

    Weckhuysen, B.M.; Groothaert, M.H.; Lievens, K.; Leeman, H.; Schoonheydt, R.A.

    2003-01-01

    The role of the bis(μ-oxo)dicopper core, i.e., [Cu2(μ-O)2]2+, in the decomposition of NO and N2O by the Cu-ZSM-5 zeolite has been studied with combined operando UV–vis monitoring of the catalyst and on-line GC analysis. An optical fiber was mounted on the outer surface of the quartz wall of the

  1. An operando optical fiber UV–vis spectroscopic study of the catalytic decomposition of NO and N2O over Cu-ZSM-5

    NARCIS (Netherlands)

    Weckhuysen, B.M.; Groothaert, M.H.; Lievens, K.; Leeman, H.; Schoonheydt, R.A.

    2003-01-01

    The role of the bis(μ-oxo)dicopper core, i.e., [Cu2(μ-O)2]2+, in the decomposition of NO and N2O by the Cu-ZSM-5 zeolite has been studied with combined operando UV–vis monitoring of the catalyst and on-line GC analysis. An optical fiber was mounted on the outer surface of the quartz wall of the plug

  2. Implementation of SPI Interface Based on Nios II%基于Nios II的SPI接口实现

    Institute of Scientific and Technical Information of China (English)

    康宾; 孙亮; 周玉娟

    2014-01-01

    The Nios II is the second generation of FPGA embedded processor of Altera company and links with the peripheral interface to construct a complete SOPC system. AD9517-1ABCPZ is a clock chip, which is configured through SPI interface to operate prior to other parts of system and provide the clock for other chips of system. The implementation of SPI interface can use many methods, and the one adopted in this paper is based on Nios II. This method has the advantages such as simple and flexible operation, short development cycle, low cost as well as easy maintenance systems, etc., which can be applied to various intermediate-speed and low-speed system design. The implementation method mainly includes hardware and software design, the hardware design includes the construction of SOPC system based on Nios II and the design of SPI-MASTER interface FPGA program;the software design includes the design of SPI read-write functions and the design of AD9517-1ABCPZ register configuration functions.%Nios II是Altera公司的第二代FPGA嵌入式处理器,和其挂接的外围接口相当于一个完整的SOPC系统, AD9517-1ABCPZ是一款时钟芯片,需通过SPI接口配置,让其先于系统的其他部分工作,为系统其它芯片提供时钟。针对SPI接口的实现,目前有很多方法,基于Nios II实现,具有简单灵活、开发周期短、成本低和系统维护方便等优点,可应用于许多中、低速系统设计。实现主要包括硬件设计和软件设计,硬件设计包括基于Nios II的SOPC系统的搭建,SPI-MASTER接口FPGA程序设计;软件设计包括SPI读写函数设计,AD9517-1ABCPZ寄存器配置函数设计。

  3. António Reis and Margarida Cordeiro, eccentric filmmakers

    Directory of Open Access Journals (Sweden)

    Lucas Tavares Neves

    2016-02-01

    Full Text Available The international symposium "António Reis and Margarida Cordeiro, eccentric filmmakers" took place in Paris between the 3rd and the 4th of June, 2015. Speakers exchanged on the political, social and poetical aspects of the duo's cinematography, as well as on the reverberations of titles such as Jaime (1974 and Trás-os-montes (1976 on the Portuguese filmic landscape of the decades that followed.

  4. Hydrogenated NiO nanoblock architecture for high performance pseudocapacitor.

    Science.gov (United States)

    Singh, Ashutosh K; Sarkar, Debasish; Khan, Gobinda Gopal; Mandal, Kalyan

    2014-04-09

    Supercapacitor electrodes are fabricated with the self-organized 3D architecture of NiO and hydrogenated NiO (H-NiO) nano-blocks (NBs) grown by the facile electrodeposition and high temperature annealing of the Ni foil on Cu substrate. The unique architecture of H-NiO NBs electrode exhibits excellent cycling stability (only 5.3% loss of its initial specific capacitance after 3000 cycles at current density of 1.1 A g(-1)) along with the high specific and areal capacitance of ∼1272 F g(-1) and 371.8 mF cm(-2), respectively at scan rate of 5 mV s(-1) compared with the pure NiO NBs electrode (∼ 865 F g(-1) and 208.2 mF cm(-2), respectively at scan rate of 5 mV s(-1)). H-NiO NBs electrode also exhibits excellent rate capability; nearly 61% specific capacity retention has been observed when the current density increases from 1.11 to 111.11 A g(-1). This electrode offers excellent energy density of 13.51 Wh kg(-1) and power density of 19.44 kW kg(-1) even at a high current density of 111.11 A g(-1). The superior pseudocapacitive performance of the H-NiO NBs electrode is because of the high electron and ion conductivity of the active material because of the incorporation of hydroxyl groups on the surface of NiO NBs.

  5. Improvements of the versatile multiaperture negative ion source NIO1

    Science.gov (United States)

    Cavenago, M.; Serianni, G.; De Muri, M.; Veltri, P.; Antoni, V.; Baltador, C.; Barbisan, M.; Brombin, M.; Galatá, A.; Ippolito, N.; Kulevoy, T.; Pasqualotto, R.; Petrenko, S.; Pimazzoni, A.; Recchia, M.; Sartori, E.; Taccogna, F.; Variale, V.; Zaniol, B.; Barbato, P.; Baseggio, L.; Cervaro, V.; Fasolo, D.; Franchin, L.; Ghiraldelli, R.; Laterza, B.; Maniero, M.; Martini, D.; Migliorato, L.; Minarello, A.; Molon, F.; Moro, G.; Patton, T.; Ravarotto, D.; Rizzieri, R.; Rizzolo, A.; Sattin, M.; Stivanello, F.; Zucchetti, S.

    2017-08-01

    The ion source NIO1 (Negative Ion Optimization 1) was developed and installed as a reduced-size model of multi-aperture sources used in neutral beam injectors. NIO1 beam optics is optimized for a 135 mA H- current (subdivided in 9 beamlets) at a Vs = 60 kV extraction voltage, with an electron-to-ion current ratio Rj up to 2. Depending on gas pressure used, NIO1 was up to now operated with Vs < 25 kV for beam extraction and Vs = 60 kV for insulation tests. The distinction between capacitively coupled plasma (E-mode, consistent with a low electron density plasma ne) and inductively coupled plasma (H-mode, requiring larger ne) was clearly related to several experimental signatures, and was confirmed for several gases, when applied radiofrequency power exceeds a given threshold Pt (with hysteresis). For hydrogen Pt was reduced below 1 kW, with a clean rf window and molybdenum liners on other walls; for oxygen Pt ≤ 400 W. Beams of H- and O- were separately extracted; since no caesium is yet introduced into the source, the expected ion currents are lower than 5 mA; this requires a lower acceleration voltage Vs (to keep the same perveance). NIO1 caesium oven was separately tested and Cs dispensers are in development. Increasing the current in the magnetic filter circuit, modifying its shape, and increasing the bias voltage were helpful to reduce Rj (still very large up to now, about 150 for oxygen, and 40 for hydrogen), in qualitative agreement with theoretical and numerical models. A second bias voltage was tested for hydrogen. Beam footprints and a spectral emission sample are shown.

  6. Museologia e patrimônio: encontros e desencontros

    Directory of Open Access Journals (Sweden)

    Marcio Ferreira Rangel

    Full Text Available Ao direcionarmos o olhar para as décadas de 1920 e 1930, podemos verificar os diferentes projetos, apresentados por parte da intelectualidade brasileira, para a área do patrimônio e dos museus. Esta assertiva poder ser confirmada por meio da análise dos diversos projetos e anteprojetos que buscavam normalizá-la. Nesse período, é posta em curso a ideia da construção de um Estado onde as elites têm papel de destaque no encaminhamento da questão política e cultural. Assim, são criados importantes instituições e órgãos, tais como o Museu Histórico Nacional (1922, o Curso de Museus (1932 e a Inspetoria de Monumentos Nacionais (1934. Tanto o Curso de Museus como a Inspetoria de Monumentos Nacionais são considerados marcos. O primeiro na institucionalização da Museologia e dos estudos de museus no Brasil. O segundo foi um dos principais antecedentes do Serviço do Patrimônio Histórico e Artístico Nacional (SPHAN, atual Instituto do Patrimônio Histórico e Artístico Nacional (IPHAN, criado em 1937. O presente artigo pretende lançar luzes nessa discussão ao analisar e problematizar o papel desempenhado por diferentes atores no processo de formação e configuração das áreas da Museologia e do Patrimônio, enfatizando as convergências e divergências existentes em suas trajetórias.

  7. In situ redox cycle of a nickel–YSZ fuel cell anode in an environmental transmission electron microscope

    DEFF Research Database (Denmark)

    Jeangros, Quentin; Faes, Antonin; Wagner, Jakob Birkedal

    2010-01-01

    Environmental transmission electron microscopy is used in combination with density functional theory calculations to study the redox stability of a nickel/yttria-stabilized zirconia solid oxide fuel cell anode. The results reveal that the transfer of oxygen from NiO to yttria-stabilized zirconia...... triggers the reduction reaction. During Ni reoxidation, the creation of a porous structure, due to mass transport, accounts for the redox instability of the Ni-based anode. Both the expansion of NiO during a redox cycle and the presence of stress in the yttria-stabilized zirconia grains are observed...

  8. NiO nanoparticle-based urea biosensor.

    Science.gov (United States)

    Tyagi, Manisha; Tomar, Monika; Gupta, Vinay

    2013-03-15

    NiO nanoparticles (NiO-NPs) have been exploited successfully for the fabrication of a urea biosensor. A thin film of NiO nanoparticles deposited on an indium tin oxide (ITO) coated glass substrate serves as an efficient matrix for the immobilisation of urease (Ur), the specific enzyme for urea detection. The prepared bioelectrode (Ur/NiO-NP/ITO/glass) is utilised for urea sensing using cyclic voltammetry and UV-visible spectroscopy. NiO nanoparticles act as electro-catalytic species that are based on the shuttling of electrons between Ni(2+) and Ni(3+) in the octahedral site and result in an enhanced electrochemical current response. The prepared bioelectrode (Ur/NiO-NPs/ITO/glass) exhibits a high sensitivity of 21.3 μA/(mM (*) cm(2)) and a good linearity in a wide range (0.83-16.65 Mm) of urea concentrations with fast response time of 5s. The low value of the Michaelis-Menten constant (K(m)=0.34 mM) indicates the high affinity of Ur towards the analyte (urea). The high catalytic activity, along with the redox behaviour of NiO-NPs, makes it an efficient matrix for the realisation of a urea biosensor.

  9. Surface magnetism of NiO investigated by magnetic spectromicroscopies

    Energy Technology Data Exchange (ETDEWEB)

    Mandal, Suman [Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012 (India); Das, Jayanta [Surface Physics and Material Science Division, Saha Institute of Nuclear Physics, Kolkata 700064 (India); Menon, Krishnakumar S.R., E-mail: krishna.menon@saha.ac.in [Surface Physics and Material Science Division, Saha Institute of Nuclear Physics, Kolkata 700064 (India)

    2016-04-15

    Highlights: • State of the art imaging of surface antiferromagnetic domains is reviewed. • Important recent results of antiferromagnetic NiO(100) surface are discussed. • Experimental approach combining XMLD-PEEM and AFM-LEEM is proposed. - Abstract: Antiferromagnetic (AFM) materials were not well respected from practical point of view until the discovery of interlayer exchange coupling in 1986 and giant magnetoresistance (GMR) in 1988–1989. Soon after, the old discovery (namely exchange anisotropy in 1956) and surface antiferromagnetism find their practical importance in magnetic recording, storage and sensor devices. However, the progress is partly hindered by limited experimental techniques to study surface AFM properties. This paper reviews recent experimental advances in the field of surface antiferromagnetism of prototype AFM oxide NiO(100), particularly using laterally resolved magnetic spectroscopy. Studies performed on bare NiO(100) single crystal and thin films using photoemission electron microscopy (PEEM) with X-ray magnetic linear dichroism (XMLD) as contrast mechanism and using a recently proposed approach utilizing the capability of a low energy electron microscope (LEEM), namely AFM-LEEM, are highlighted. We expect that AFM-LEEM in combination with XMLD-PEEM will soon explore more finer aspects AFM materials.

  10. Isolation and characterization of biogenic calcium carbonate/phosphate from oral bacteria and their adhesion studies on YSZ-coated titanium substrate for dental implant application

    Indian Academy of Sciences (India)

    GOBI SARAVANAN KALIARAJ; KAMALAN KIRUBAHARAN; G PRADHABAN; P KUPPUSAMI; VINITA VISHWAKARMA

    2016-04-01

    Biogenic calcium carbonate/phosphate were isolated and characterized from oral bacteria (CPOB). The crystalline nature and morphology of calcium carbonate/phosphate were characterized by X-ray diffraction (XRD)and field emission scanning electron microscopy (FESEM), respectively. XRD analysis revealed the cubic phase of YSZ coating as well as biogenic calcium carbonate (rhombohedral) and calcium phosphate oxide (hexagonal) wasobserved from CPOB. FESEM confirmed the extracellular synthesis of calcium compounds. Bacterial adhesion result reveals that YSZ coating drastically reduce bacterial invasion than titanium substrate.

  11. Design of SD Memory Card Interface Based on Nios II Softcore%基于Nios II软核处理器的SD卡接口设计

    Institute of Scientific and Technical Information of China (English)

    杜鹏

    2013-01-01

    随着FPGA的低成本化和整合资源的不断增强,FPGA在整个嵌入式市场中的份额在不断增加。基于FPGA的NiosII软核以其高度的设计灵活性和完全可定制性在现今电子产品设计及工业控制中扮演着重要的角色。此外,以SD卡为代表的大容量存储卡成为消费电子类产品最重要的存储媒体。基于NiosII软核处理器来读写SD卡的接口设计在诸多电子系统中的使用也愈来愈多。文中给出了基于NiosII软核处理器的SD卡接口设计方案,并介绍了NiosII的驱动架构,给出SD存储卡在NiosII软核上的驱动程序设计。%With low-cost FPGA and its growing integration of resources,the share of FPGA in the entire embedded market continues to increase. FPGA-based Nios II soft core for its high degree of design flexibility and full customizability plays an important role in today's electronic products and industrial control design. In addition,the SD mass storage card becomes the most important media in consumer electronics products. SD card reader interface design based on the Nios II soft core processor is more and more used in many electronic systems. In this paper,proposed the Nios II soft core processor based SD card interface design and Nios II driver architecture. In addition, presented the design of the SD memory card driver based on Nios II soft core.

  12. Oxidation resistance of Al2O3-nanostructured/CSZ composite compared to conventional CSZ and YSZ thermal barrier coatings

    Science.gov (United States)

    Keyvani, A.; Bahamirian, M.

    2016-10-01

    Thermal barrier coatings are widely used in combustion sections of turbine engines, however, their main disadvantage is the spallation from the bond coat, occurring due to oxidation and formation of thermally grown oxide (TGO). In this paper, the oxidation resistance of yttria stabilized zirconia (YSZ), ceria stabilized zirconia (CSZ), and Al2O3-nanostructured/CSZ composite coatings have been studied and compared with each other. Samples were heated in air at 1100 °C using an electrical furnace. Three types of the top coats were applied by thermal spray technique on IN738LC base metal. Scanning electron microscopy was used to study the microstructure of the coatings before and after the oxidation. The experimental results showed that Al2O3-nanostructured/CSZ composite coating exhibits considerably better oxidation resistance compared to conventional YSZ and CSZ coatings. The microstructural analysis indicated a smaller growth of TGO in the Al2O3-nanostructured/CSZ composite coating, improving the oxidation resistance of the coating.

  13. Mechanical properties at the nanometer scale of GDC and YSZ used as electrolytes for solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Morales, M., E-mail: mmorales@ub.edu [Departamento de Ciencia de los Materiales e Ingenieria Metalurgica, Universidad de Barcelona, C/Marti i Franques, 1 08028 Barcelona (Spain)] [Instituto de Ciencia de los Materiales de Barcelona, ICMAB-CSIC, Campus de la UAB, 08193 Bellaterra, Barcelona (Spain); Roa, J.J.; Capdevila, X.G.; Segarra, M. [Departamento de Ciencia de los Materiales e Ingenieria Metalurgica, Universidad de Barcelona, C/Marti i Franques, 1 08028 Barcelona (Spain); Pinol, S. [Instituto de Ciencia de los Materiales de Barcelona, ICMAB-CSIC, Campus de la UAB, 08193 Bellaterra, Barcelona (Spain)

    2010-04-15

    The Young's modulus (E), hardness (H) and fracture toughness (K{sub IC}) of various compositions of gadolinia doped-ceria (GDC, Gd{sub x}Ce{sub 1-x}O{sub 2-x/2}, 0.1 {<=} x {<=} 0.2) and yttria-stabilized zirconia (YSZ, Y{sub 0.08}Zr{sub 0.92}O{sub 1.96}) electrolytes were investigated by nanoindentation. All samples were produced by the sol-gel method, formed by uniaxial pressure and sintered at 1400 deg. C. In order to determine the mechanical properties, a Berkovich diamond tip was employed at applied loads of 5, 10, 30, 100 and 500 mN. The results were interpreted by the Oliver-Pharr method and values of K{sub IC} were determined using the method of Palmqvist cracks. The residual imprints were observed by field emission scanning electron microscopy. The results obtained showed that the H, E and K{sub IC} of GDC decreased with increasing gadolinia concentration, due to the oxygen vacancies generated by the dopant addition. As a result, the mechanical properties of GDC were significantly lower than those of YSZ electrolyte.

  14. Ordered mesoporous NiO with thin pore walls and its enhanced sensing performance for formaldehyde.

    Science.gov (United States)

    Lai, Xiaoyong; Shen, Guoxin; Xue, Ping; Yan, Bingqin; Wang, Hong; Li, Peng; Xia, Weitao; Fang, Junzhuo

    2015-03-07

    A class of formaldehyde (HCHO) gas sensors with a high response were developed based on ordered mesoporous NiO, which were synthesized via the nanocasting route by directly using mesoporous silica as the hard template. A series of mesoporous NiO with different textural parameters such as specific surface area, pore size, pore wall thickness were achieved by selecting mesoporous silica with different pore sizes as templates. The gas sensing properties for formaldehyde (HCHO) of the NiO specimens were examined. The results show that this mesoporous NiO possesses a much higher response to HCHO even at low concentration levels than the bulk NiO, and a larger specific surface area and pore size as well as thinner pore walls would be beneficial for enhancing the sensing properties of NiO.

  15. In-operando elucidation of bimetallic CoNi nanoparticles during high-temperature CH 4 /CO 2 reaction

    KAUST Repository

    AlSabban, Bedour

    2017-05-02

    Dry reforming of methane (DRM) proceeds via CH4 decomposition to leave surface carbon species, followed by their removal with CO2-derived species. Reactivity tuning for stoichiometric CH4/CO2 reactants was attempted by alloying the non-noble metals Co and Ni, which have high affinity with CO2 and high activity for CH4 decomposition, respectively. This study was focused on providing evidence of the capturing surface coverage of the reactive intermediates and the associated structural changes of the metals during DRM at high temperature using in-operando X-ray absorption spectroscopy (XAS). On the Co catalysts, the first-order effects with respect to CH4 pressure and negative-order effects with respect to CO2 pressure on the DRM rate are consistent with the competitive adsorption of the surface oxygen species on the same sites as the CH4 decomposition reaction. The Ni surface provides comparatively higher rates of CH4 decomposition and the resultant DRM than the Co catalyst but leaves some deposited carbon on the catalyst surface. In contrast, the bimetallic CoNi catalyst exhibits reactivity towards the DRM but with kinetic orders resembling Co catalyst, producing negligible carbon deposition by balancing CH4 and CO2 activation. The in-operando X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) measurements confirmed that the Co catalyst was progressively oxidized from the surface to the bulk with reaction time, whereas CoNi and Ni remained relatively reduced during DRM. Density functional theory (DFT) calculation considering the high reaction temperature for DRM confirmed the unselective site arrangement between Co and Ni atoms in both the surface and bulk of the alloy nanoparticle (NP). The calculated heat of oxygen chemisorption became more exothermic in the order of Ni, CoNi, Co, consistent with the catalytic behavior. The comprehensive experimental and theoretical evidence provided herein clearly suggests

  16. Thickness dependent ferromagnetism in thermally decomposed NiO thin films

    Science.gov (United States)

    Ravikumar, Patta; Kisan, Bhagaban; Perumal, Alagarsamy

    2016-11-01

    We report the effects of film thickness, annealing temperature and annealing environments on thermal decomposition behavior and resulting magnetic properties of NiO (t=50-300 nm) thin films. All the NiO films were prepared directly on thermally oxidized Si at ambient temperature using magnetron sputtering technique and post annealed at different temperatures (TA) under vacuum and oxygen atmospheres. As-deposited films exhibit face centered cubic structure with large lattice constant due to strain induced during sputtering process. With increasing TA, the lattice constant decreases due to the release of strain and thickness dependent thermal decomposition reaction of NiO into Ni has been observed for the NiO films annealed at 500 °C under vacuum condition. As a result, the antiferromagnetic nature of the as-deposited NiO films transforms into ferromagnetic one with dominant thickness dependent ferromagnetic behavior at room temperature. In addition, the existence of both Ni and NiO phases in the annealed NiO films shows noticeable exchange bias under field cooling condition. The behavior of thermal decomposition was not observed for the NiO films annealed under oxygen condition which results in no detectable change in the magnetic properties. The observed results are discussed on the basis of thickness dependent thermal decomposition in NiO films with increasing TA and changing annealing conditions.

  17. Ethanol Sensing Properties of Au-functionalized NiO Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sunghoon; Kheel, Hyejoon; Sun, Gun-Joo; Hyun, Soong Keun; Park, Sang Eon; Lee, Chongmu [Inha University, Incheon (Korea, Republic of)

    2016-05-15

    Pristine and Au-functionalized nickel oxide (NiO) nanoparticles were synthesized via a simple solvo thermal route and the ethanol sensing properties of multiple-networked Au-doped and undoped NiO nanoparticle sensors were examined. The pristine and Au-functionalized NiO nanoparticle sensor showed responses of 442 and 273%, respectively, to 1000 ppm of ethanol at 325 .deg. C. The Au-functionalized NiO nanoparticle sensor showed faster response than the pristine NiO counterpart, whereas the recovery time of the former was similar to that of the latter. The optimal operating temperature of the pristine and Au-functionalized NiO nanoparticles was 325 and 350 .deg. C, respectively, by Au-doping. Both the pristine and Au-functionalized NiO nanoparticle sensors showed selectivity for ethanol gas over methanol, acetone, benzene, and toluene gases. The underlying mechanism of the enhanced sensing performance of the Au-functionalized NiO nanoparticles toward ethanol might be due to modulation of the depletion layer formed around Au particles and the Schottky barriers formed at the Au-NiO junction accompanying ethanol adsorption and desorption, the spill-over effect and high catalytic activity of Au nanoparticles and the smaller diameter of the particles in the Au-functionalized NiO sensor.

  18. Manufacturing of Composite Coatings by Atmospheric Plasma Spraying Using Different Feed-Stock Materials as YSZ and MoSi2

    Science.gov (United States)

    Koch, D.; Mauer, G.; Vaßen, R.

    2017-02-01

    Yttria-stabilized zirconia (YSZ) is the state-of-the-art material for the top coat of thermal barrier coatings. To increase the efficiency and lifetime of gas turbines, the integration of MoSi2 as a healing material was proposed. A new method of manufacture was explored in order to enable the spraying of a homogeneous mixed layer of YSZ and MoSi2. As the chemical and physical properties of these powders are very different, they require contrasting process conditions. Due to the evaporation of Si from MoSi2 at spraying conditions suitable for YSZ, more moderate conditions and a shorter time of flight are required for depositing MoSi2. At the same time, the spraying conditions still need to be sufficient for melting the YSZ particles in order to produce a coating. To obtain a homogeneous mixture, both conditions can be matched using an injection system that allows powder injection at two different locations of the plasma jet. Two-color pyrometry during flight (DPV-2000, Tecnar) was used to monitor the actual particle temperature. By optimizing the injection point for the MoSi2, a mixed coating was obtained without decomposition of the MoSi2, which has been analyzed by means of XRD and SEM.

  19. Composite Sr- and V-doped LaCrO3/YSZ sensor electrode operating at low oxygen levels

    DEFF Research Database (Denmark)

    Lund, Anders; Jacobsen, Torben; Hansen, Karin Vels;

    2012-01-01

    A porous composite electrode of La0.8Sr0.2Cr0.97V0.03O3 -delta (LSCV) and yttria-stabilised zirconia (YSZ) was evaluated as a possible candidate for high-temperature potentiometric oxygen sensor measuring electrodes. The oxygen processes at the electrode were characterised by performing electroch...

  20. Fabrication of YBCO/YSZ and YBCO/MgO thick films using electrophoretic deposition with top-seeded melt growth process

    Institute of Scientific and Technical Information of China (English)

    Zhu Ya-Bin; Zhou Yue-Liang; Wang Shu-Fang; Liu Zhen; Zhang Qin; Chen Zheng-Hao; Lü Hui-Bin; Yang Guo-Zhen

    2004-01-01

    Superconducting thick films were grown on single crystals MgO and YSZ by electrophoretic deposition with Y2BaCuOs(Y211) addition. YBCO thick films were then accomplished by sintering the precursor films above the peritectic temperature. Single crystals of MgO (3×3×0.5mm3) were used as top-seed to control crystal structure of the thick films. As shown by scanning electron microscopy, the morphologies of YBCO/YSZ and YBCO/MgO thick films are spherulitic texture and platelet type. The critical temperature is ~89 K for the YBCO/YSZ thick film; the onset transition temperature is 86.4 K and the transition width is ~3 K for YBCO/MgO thick film. The critical current densities (as determined by Bean model) are, in A/cm2, 3870 (77K) for YBCO/YSZ thick films and 2399 (77K) for YBCO/MgO thick films, which are comparable to the best Jc reported of the thick films prepared by the same method.

  1. A Preliminary Study on WO3‐Infiltrated W–Cu–ScYSZ Anodes for Low Temperature Solid Oxide Fuel Cells

    DEFF Research Database (Denmark)

    Abdul Jabbar, Mohammed Hussain; Reddy Sudireddy, Bhaskar; Høgh, Jens Valdemar Thorvald

    2012-01-01

    Preparation and electrochemical characterization of WO3‐infiltrated 0.48W–0.52Cu–ScYSZ (WCS) anode for solid oxide fuel cell are reported. The DC conductivity of a WO3 ceramic was 1,200 and 24 S cm–1 in reducing and oxidizing atmospheres, respectively, at 650 °C. WCS porous backbones in the form ...

  2. DESIGN AND IMPLEMENTATION OF CUSTOM INSTRUCTIONS IN NIOS II PROCESSOR%NIOS II处理器中定制指令的设计与实现

    Institute of Scientific and Technical Information of China (English)

    卢德良; 周学功; 彭澄廉

    2007-01-01

    概要介绍NIOS II处理器,详述NIOS II处理器中定制指令的硬件实现和软件接口.并结合实例说明在进行SOPC设计时,可以把强实时软件算法或费时的软件计算作为定制指令,加入到NIOS II处理器指令集中,提高系统性能.

  3. Nios Ⅱ处理器在数字信号处理中的应用%Application of NIOS Ⅱ Processor in Digital Signal Process

    Institute of Scientific and Technical Information of China (English)

    赵佩丽; 李小珉; 卞小林

    2007-01-01

    本文介绍了一种基于嵌入式软核处理器Nios II实现FFT算法的方法;分析了新一代Nios II内核处理器的特点,并从硬件和软件两个方面来论述Nios II系统设计的开发流程;最后,分析了该系统在数字信号处理领域的应用价值.

  4. Geografia dos domínios de internet no Brasil

    Directory of Open Access Journals (Sweden)

    Marcelo Paiva da Motta

    2013-11-01

    Full Text Available The aim of this paper is to analyze the spatial pattern of internet on a national scale in the content offer dimension. We use domain name resgistration as a proxy of the location where the informations are produced. We start from the hypothesys that the domain spatiality is precisely attached to material processes of society. This is verified by comparing domain names spatial pattern with the distribution of demographics and economic activity in general. The conclusion is that the internet domain geography is highly concentrated despite the anti-geographic bias that emerged with internet diffusion. The results are consistent with the institutionalist approach, in which online operating firms tend to cluster mainly in metropolises, interweaving with the previous economic environment.O objetivo deste artigo é analisar a distribuição espacial da Internet na escala nacional, na dimensão da oferta de conteúdo. Para tanto, foi utilizado o registro de domínios como proxy da localização onde as informações são produzidas. Partiu-se da hipótese de que a espacialidade dos domínios, a despeito de sua imaterialidade, não prescinde de uma ancoragem espacial precisa, relacionando-se com processos materiais da sociedade. Isto é verificado pela comparação dos padrões espaciais dos domínios com a demografia e a distribuição das atividades econômicas em geral no território. Conclui-se que a geografia dos domínios é extremamente concentrada, contrariando o viés antigeográfico suscitado pela disseminação da Internet. Os resultados são consistentes com a abordagem institucionalista, pela qual as empresas que operam online tendem a se aglomerar nas metrópoles, integrando-se com o ambiente econômico prévio.

  5. Caipirinha: o coquetel como signo do patrimônio

    OpenAIRE

    Mazaro, Ricardo Anson

    2005-01-01

    A dissertação objetiva apresentar a Caipirinha como um signo absoluto do patrimônio cultural na hospitalidade brasileira. Nesse enfoque é observado o fato da hospitalidade se desenvolver através dos laços sociais promovidos pelo consumo da bebida, e os rituais que envolvem o referido ato social. Para tanto, discorremos inicialmente sobre a história das bebidas na humanidade, assim como a relevância da coquetelaria na sociabilidade humana. Do Brasil colonial ao contemporâneo, a cachaça, princi...

  6. Patrimônio cultural gastronômico

    OpenAIRE

    Muller, Silvana Graudenz

    2012-01-01

    Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia e Gestão do Conhecimento A pesquisa trata da preservação do conhecimento tradicional gastronômico reconhecido como patrimônio cultural a ser protegido. Esse conhecimento cultural é, sobretudo, tácito e compreende os saberes e fazeres transmitidos de pais para filhos que se encontram ameaçados frente ao fenômeno da globalização. O estudo descreve as formas de conversão do c...

  7. An operando DRIFTS investigation into the resistance against CO2 poisoning of a Rh/alumina catalyst during toluene hydrogenation.

    Science.gov (United States)

    Scalbert, Julien; Meunier, Frederic C; Daniel, Cecile; Schuurman, Yves

    2012-02-21

    CO(2) is a major contaminant of renewable H(2) derived from biomass fermentation. The effect of the presence of CO(2) on the activity of alumina-supported Pt and Rh catalysts used for the hydrogenation of toluene at 348 K was investigated. The use of operando diffuse reflectance spectroscopy (DRIFTS) was crucial in unravelling the changes in the nature and abundance of species adsorbed at the sample surface and relating those to the changes of catalytic activity. Rhodium supported on alumina was only partly deactivated by the introduction of CO(2) during the hydrogenation of toluene, contrary to the case of Pt/alumina. Rh was only partially covered by carbonyl species derived from CO(2) and it was shown that toluene could successfully compete with some of the linearly adsorbed carbonyls for adsorption. The alumina support stored many CO(2)-derived adsorbates (carbonates, hydrogenocarbonates, carboxylates) that could spill over to the metal and form carbonyl species even after the removal of CO(2) from the feed.

  8. Discovering the active sites for C3 separation in MIL-100(Fe) by using operando IR spectroscopy.

    Science.gov (United States)

    Wuttke, Stefan; Bazin, Philippe; Vimont, Alexandre; Serre, Christian; Seo, You-Kyong; Hwang, Young Kyu; Chang, Jong-San; Férey, Gérard; Daturi, Marco

    2012-09-17

    A reducible MIL-100(Fe) metal-organic framework (MOF) was investigated for the separation of a propane/propene mixture. An operando methodology was applied (for the first time in the case of a MOF) in order to shed light on the separation mechanism. Breakthrough curves were obtained as in traditional separation column experiments, but monitoring the material surface online, thus providing evidences on the adsorption sites. The qualitative and quantitative analyses of Fe(II) and, to some extent, Fe(III) sites were possible, upon different activation protocols. Moreover, it was possible to identify the nature and the role of the active sites in the separation process by selective poisoning of one family of sites: it was clearly evidenced that the unsaturated Fe(II) sites are mainly responsible for the separation effect of the propane/propene mixture, thanks to their affinity for the unsaturated bonds, such as the C=C entities in propene. The activity of the highly concentrated Fe(III) sites was also highlighted.

  9. Rapid Mapping of Lithiation Dynamics in Transition Metal Oxide Particles with Operando X-ray Absorption Spectroscopy.

    Science.gov (United States)

    Nowack, Lea; Grolimund, Daniel; Samson, Vallerie; Marone, Federica; Wood, Vanessa

    2016-02-24

    Since the commercialization of lithium ion batteries (LIBs), layered transition metal oxides (LiMO2, where M = Co, Mn, Ni, or mixtures thereof) have been materials of choice for LIB cathodes. During cycling, the transition metals change their oxidation states, an effect that can be tracked by detecting energy shifts in the X-ray absorption near edge structure (XANES) spectrum. X-ray absorption spectroscopy (XAS) can therefore be used to visualize and quantify lithiation kinetics in transition metal oxide cathodes; however, in-situ measurements are often constrained by temporal resolution and X-ray dose, necessitating compromises in the electrochemistry cycling conditions used or the materials examined. We report a combined approach to reduce measurement time and X-ray exposure for operando XAS studies of lithium ion batteries. A highly discretized energy resolution coupled with advanced post-processing enables rapid yet reliable identification of the oxidation state. A full-field microscopy setup provides sub-particle resolution over a large area of battery electrode, enabling the oxidation state within many transition metal oxide particles to be tracked simultaneously. Here, we apply this approach to gain insights into the lithiation kinetics of a commercial, mixed-metal oxide cathode material, nickel cobalt aluminium oxide (NCA), during (dis)charge and its degradation during overcharge.

  10. 3D printed sample holder for in-operando EPR spectroscopy on high temperature polymer electrolyte fuel cells.

    Science.gov (United States)

    Niemöller, Arvid; Jakes, Peter; Kayser, Steffen; Lin, Yu; Lehnert, Werner; Granwehr, Josef

    2016-08-01

    Electrochemical cells contain electrically conductive components, which causes various problems if such a cell is analyzed during operation in an EPR resonator. The optimum cell design strongly depends on the application and it is necessary to make certain compromises that need to be individually arranged. Rapid prototyping presents a straightforward option to implement a variable cell design that can be easily adapted to changing requirements. In this communication, it is demonstrated that sample containers produced by 3D printing are suitable for EPR applications, with a particular emphasis on electrochemical applications. The housing of a high temperature polymer electrolyte fuel cell (HT-PEFC) with a phosphoric acid doped polybenzimidazole membrane was prepared from polycarbonate by 3D printing. Using a custom glass Dewar, this fuel cell could be operated at temperatures up to 140°C in a standard EPR cavity. The carbon-based gas diffusion layer showed an EPR signal with a characteristic Dysonian line shape, whose evolution could be monitored in-operando in a non-invasive manner.

  11. In operando visualization of hydride-graphite composites during cyclic hydrogenation by high-resolution neutron imaging

    Science.gov (United States)

    Pohlmann, Carsten; Herbrig, Kai; Gondek, Łukasz; Kardjilov, Nikolay; Hilger, André; Figiel, Henryk; Banhart, John; Kieback, Bernd; Manke, Ingo; Röntzsch, Lars

    2015-03-01

    Hydrogen solid-state storage in metal hydrides has attracted remarkable attention within the past decades due to their high volumetric storage densities at low operating pressures. In particular, recently emerged hydride-graphite composites (HGC) can enable a safe, reliable and very compact hydrogen storage solution for various applications. In this regard, only little is known about the activation behavior of such HGC, their cycle stability and degradation effects. Because of the high sensitivity to hydrogen, neutron imaging offers a distinctive approach to examine in operando reaction fronts, swelling effects and microstructural changes of hydrogen absorbing materials with high spatial and temporal resolution. In this contribution, a comprehensive analysis of various phenomena during activation and cycling of HGC based on a Ti-Mn hydrogen absorbing alloy and expanded natural graphite is reported for the first time. A neutron radiography and tomography set-up with a spatial resolution down to 7 μm was utilized allowing highest detection precision. During initial hydrogenation, regions with enhanced reactivity are observed which contradicts a theoretically expected homogeneous reactivity inside the HGC. These active regions grow with the number of hydrogenation-dehydrogenation cycles until the whole HGC volume uniformly participates in the hydrogen sorption reaction. With regard to long-term hydrogenation-dehydrogenation cycling, inhomogeneous swelling effects were observed from which essential conclusions for technical HGC-based tank systems can be derived.

  12. Rapid Mapping of Lithiation Dynamics in Transition Metal Oxide Particles with Operando X-ray Absorption Spectroscopy

    Science.gov (United States)

    Nowack, Lea; Grolimund, Daniel; Samson, Vallerie; Marone, Federica; Wood, Vanessa

    2016-01-01

    Since the commercialization of lithium ion batteries (LIBs), layered transition metal oxides (LiMO2, where M = Co, Mn, Ni, or mixtures thereof) have been materials of choice for LIB cathodes. During cycling, the transition metals change their oxidation states, an effect that can be tracked by detecting energy shifts in the X-ray absorption near edge structure (XANES) spectrum. X-ray absorption spectroscopy (XAS) can therefore be used to visualize and quantify lithiation kinetics in transition metal oxide cathodes; however, in-situ measurements are often constrained by temporal resolution and X-ray dose, necessitating compromises in the electrochemistry cycling conditions used or the materials examined. We report a combined approach to reduce measurement time and X-ray exposure for operando XAS studies of lithium ion batteries. A highly discretized energy resolution coupled with advanced post-processing enables rapid yet reliable identification of the oxidation state. A full-field microscopy setup provides sub-particle resolution over a large area of battery electrode, enabling the oxidation state within many transition metal oxide particles to be tracked simultaneously. Here, we apply this approach to gain insights into the lithiation kinetics of a commercial, mixed-metal oxide cathode material, nickel cobalt aluminium oxide (NCA), during (dis)charge and its degradation during overcharge. PMID:26908198

  13. Combining operando synchrotron X-ray tomographic microscopy and scanning X-ray diffraction to study lithium ion batteries

    Science.gov (United States)

    Pietsch, Patrick; Hess, Michael; Ludwig, Wolfgang; Eller, Jens; Wood, Vanessa

    2016-01-01

    We present an operando study of a lithium ion battery combining scanning X-ray diffraction (SXRD) and synchrotron radiation X-ray tomographic microscopy (SRXTM) simultaneously for the first time. This combination of techniques facilitates the investigation of dynamic processes in lithium ion batteries containing amorphous and/or weakly attenuating active materials. While amorphous materials pose a challenge for diffraction techniques, weakly attenuating material systems pose a challenge for attenuation-contrast tomography. Furthermore, combining SXRD and SRXTM can be used to correlate processes occurring at the atomic level in the crystal lattices of the active materials with those at the scale of electrode microstructure. To demonstrate the benefits of this approach, we investigate a silicon powder electrode in lithium metal half-cell configuration. Combining SXRD and SRXTM, we are able to (i) quantify the dissolution of the metallic lithium electrode and the expansion of the silicon electrode, (ii) better understand the formation of the Li15Si4 phase, and (iii) non-invasively probe kinetic limitations within the silicon electrode. A simple model based on the 1D diffusion equation allows us to qualitatively understand the observed kinetics and demonstrates why high-capacity electrodes are more prone to inhomogeneous lithiation reactions. PMID:27324109

  14. 3D printed sample holder for in-operando EPR spectroscopy on high temperature polymer electrolyte fuel cells

    Science.gov (United States)

    Niemöller, Arvid; Jakes, Peter; Kayser, Steffen; Lin, Yu; Lehnert, Werner; Granwehr, Josef

    2016-08-01

    Electrochemical cells contain electrically conductive components, which causes various problems if such a cell is analyzed during operation in an EPR resonator. The optimum cell design strongly depends on the application and it is necessary to make certain compromises that need to be individually arranged. Rapid prototyping presents a straightforward option to implement a variable cell design that can be easily adapted to changing requirements. In this communication, it is demonstrated that sample containers produced by 3D printing are suitable for EPR applications, with a particular emphasis on electrochemical applications. The housing of a high temperature polymer electrolyte fuel cell (HT-PEFC) with a phosphoric acid doped polybenzimidazole membrane was prepared from polycarbonate by 3D printing. Using a custom glass Dewar, this fuel cell could be operated at temperatures up to 140 °C in a standard EPR cavity. The carbon-based gas diffusion layer showed an EPR signal with a characteristic Dysonian line shape, whose evolution could be monitored in-operando in a non-invasive manner.

  15. A high-temperature, ambient-pressure ultra-dry operando reactor cell for Fourier-transform infrared spectroscopy

    Science.gov (United States)

    Köck, Eva-Maria; Kogler, Michaela; Pramsoler, Reinhold; Klötzer, Bernhard; Penner, Simon

    2014-08-01

    The construction of a newly designed high-temperature, high-pressure FT-IR reaction cell for ultra-dry in situ and operando operation is reported. The reaction cell itself as well as the sample holder is fully made of quartz glass, with no hot metal or ceramic parts in the vicinity of the high-temperature zone. Special emphasis was put on chemically absolute water-free and inert experimental conditions, which includes reaction cell and gas-feeding lines. Operation and spectroscopy up to 1273 K is possible, as well as pressures up to ambient conditions. The reaction cell exhibits a very easy and variable construction and can be adjusted to any available FT-IR spectrometer. Its particular strength lies in its possibility to access and study samples under very demanding experimental conditions. This includes studies at very high temperatures, e.g., for solid-oxide fuel cell research or studies where the water content of the reaction mixtures must be exactly adjusted. The latter includes all adsorption studies on oxide surfaces, where the hydroxylation degree is of paramount importance. The capability of the reaction cell will be demonstrated for two selected examples where information and in due course a correlation to other methods can only be achieved using the presented setup.

  16. Influence of atmospheric plasma spray parameters on YSZ coatings obtained from micro and nano structured feedstocks; Influencia de los parametros de proyeccion por plasma atmosferico en recubrimientos de YSZ obtenidos a partir de polvos micro y nanoestructurados

    Energy Technology Data Exchange (ETDEWEB)

    Carpio, P.; Bannier, E.; Borrell, A.; Salvador, M. d.; Sanchez, E.

    2014-07-01

    In the present work, the influence of atmospheric plasma spray (APS) parameters on the deposition of two commercial YSZ feedstocks, one conventional and one non-conductor's, has been studied. First the study focused on how the variability of the different parameters affects the particle behaviour during spraying. For this purpose, a sensor which enables to measure the particle temperature and velocity inside the plasma was used. Once the spraying parameters influence was known, both powders were deposited by APS onto stainless steel substrates modifying the higher influencing parameters. These coatings have been characterised and the influence of the particle behaviour on the coating microstructure and properties has been analysed. This work concludes the spraying parameters variation affects on the particle velocity and temperature inside the plasma plume and this behaviour influences, in turn but in a different way, on the final coating characteristics when using different powders (micro- and nano structured). (Author)

  17. Influence of solvent on the morphology and microstructure of YSZ films obtained by spray pyrolysis technique; Influencia do solvente na morfologia e microestrutura de filmes de YSZ obtidos pela tecnica spray pirolise

    Energy Technology Data Exchange (ETDEWEB)

    Falcade, T.; Oliveira, G.B.; Mueller, I.L.; Malfatti, C.F., E-mail: tiagocoti@gmail.co, E-mail: celia.malfatti@ufrgs.b [Universidade Federal do Rio Grande do Sul (LAPEC/PPGEM/UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-graduacao em Engenharia de Minas. Lab. de Pesquisa em Corrosao; Tarrago, D.P.; Sousa, V.C.; Bergmann, C.P. [Universidade Federal do Rio Grande do Sul (PPGEM/UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-graduacao em Engenharia de Minas; Souza, M.M.V.M. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil)

    2010-07-01

    This work aims to investigate the influence of solvent used for the deposition of thin films of yttria stabilized zirconia (YSZ) on porous substrate. The films were obtained directly on the porous LSM substrate by spray pyrolysis technique, which consists of spraying a precursor solution containing salts of zirconium (Zr (C{sub 6}H{sub 7}O{sub 2}) 4) and yttrium (YCl{sub 3}.6H{sub 2}O), dissolved in specific solvents, on the heated substrate. The use of solvents with different boiling points and viscosity aims the optimization of experimental operating parameters to obtain homogeneous and dense films suitable for application as electrolyte in fuel cells, solid oxide (SOFC). The films were characterized by scanning electron microscopy, infrared spectroscopy and X-ray diffraction. (author)

  18. Optimized functionally graded La{sub 2}Zr{sub 2}O{sub 7}/8YSZ thermal barrier coatings fabricated by suspension plasma spraying

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chaohui [Laboratory of Nano Surface Engineering, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Wang, You, E-mail: wangyou@hit.edu.cn [Laboratory of Nano Surface Engineering, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Fan, Shan; You, Yuan [College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Wang, Liang [Key Laboratory of Inorganic Coating Materials, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201899 (China); Yang, Changlong [College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Sun, Xiaoguang [National Engineering Research Center for High-speed EMU, CSR Qingdao Sifang Co. Ltd., Qingdao 266111 (China); Li, Xuewei [Laboratory of Nano Surface Engineering, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2015-11-15

    In this paper, an optimized functionally graded coating (OFGC) was successfully fabricated by suspension plasma spraying (SPS) with feedstocks of the suspension of nanoparticles. La{sub 2}Zr{sub 2}O{sub 7}/8YSZ OFGC with gradual compositional variation along the through-thickness direction is proposed to mitigate spallation and crack formation owing to the high residual stresses caused by frequent thermal cycling for TBCs. The single ceramic layer coatings (SCLC) of LZ and double ceramic layer coatings (DCLC) of LZ/8YSZ were fabricated by SPS as comparison. The phase composition and microstructure of the SCLC, OFGC and DCLC were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and Energy Dispersive Spectrometer (EDS). Moreover, the thermal cycling tests were carried out to evaluate their thermal shock behavior. Changes in weight and morphology of specimens were analyzed during thermal cycling tests. The results showed that OFGC has extended lifetime compared with SCLC and DCLC. The failure of DCLC with clear interface between different ceramic layers occurred via delamination mode, as a result of crack initiation and propagation generated by thermal mismatch between LZ and 8YSZ. While the failure of OFGC occurred in thermally grown oxide (TGO) layers, indicating that the gradual compositional variation avoided thermal stress concentration in the top ceramic layers. - Highlights: • Optimized functionally graded coatings and double ceramic layer coatings were deposited by suspension plasma spray. • The graded area of OFGC is continuously changed from inner 8YSZ to outer La{sub 2}Zr{sub 2}O{sub 7} (LZ). • The OFGC shows a more extended thermal cycling life than the LZ SCLC and LZ/8YSZ DCLC. • Various failure mechanisms were proposed to explain thermal cycling behavior.

  19. Synthesis and characterization of NiO nanoparticles by Pechini method; Sintese e caracterizacao de nanoparticulas de NiO pelo metodo Pechini

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, A.; Ribeiro, M.A.; Costa, A.C.F.M.; Gama, L. [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Dept. de Engenharia de Materiais; Bernardi, M.I.B. [Universidade de Sao Paulo (IFSC/USP), Sao Carlos, SP (Brazil). Inst. de Fisica

    2009-07-01

    In recent years, ultrafine magnetic particles of NiO have attracting the attention because of its unknown behavior, enormous scientific potential and technological application. Some of its more important properties are accented magnetic moments, double dynamic exchange, quantization of wave of spin and etc. In this context, this work has for objective to synthesize and to characterize nanoparticles of NiO for the Pechini method. The powder was analyzed by X-rays diffraction. The results of scanning electron microscopy, adsorption of nitrogen. The analysis of X-rays diffraction of the sample showed single-phase peaks of NiO, with crystallite size close to 38 nm. The surface area was 6.44 m{sup 2}/g. The image from scanning electron microscopy shows soft homogeneous agglomerates. The Pechini synthesis was efficient in the production of powders of NiO nano metrics and single-phase. (author)

  20. Intrinsic pinning and current percolation signatures in E-J characteristics of Si/YSZ/CeO2/YBCO layouts

    Science.gov (United States)

    Botta, D.; Camerlingo, C.; Chiodoni, A.; Fabbri, F.; Gerbaldo, R.; Ghigo, G.; Gozzelino, L.; Laviano, F.; Minetti, B.; Pirri, C. F.; Rombolà, G.; Tallarida, G.; Tresso, E.; Mezzetti, E.

    2005-12-01

    In the context of superconducting electronics integrated with traditional silicon-based electronics we grew Si/YSZ/CeO2/YBa2Cu3O7-x architectures by means of the scalable magnetron sputtering growth technique. In this paper we report on structural, surface and electrical transport characterization of typical multilayers. We focus on the electrical transport characterization in the temperature range 18 30 K of c-axis YBa2Cu3O7-x films grown on top of several (001) oriented buffered substrates. The electric field vs. current density (E-J) curves exhibit step-like behaviour in correspondence to the transition between the non-dissipative and the flux-flow regimes. This trend is accompanied by the signature of linearly correlated pinning. On the other hand, in the flux-flow regime clear signatures of weak-link behaviour and current percolation are exhibited. In this complex framework possible future applications are discussed.

  1. Influences of Mechanical Vibration on Rapidly Solidified Al2O3/YSZ Ceramics Prepared by Combustion Synthesis

    Institute of Scientific and Technical Information of China (English)

    ZHAO Zhong-min; ZHANG Long; WANG Wei-guo; ZHANG Shi-yue

    2006-01-01

    Al2O3/YSZ composite ceramics was fabricated with combustion synthesis technology, and the influences of mechanical vibration on its microstructures and properties were investigated. It is found that under the mechanical vibration of ever-increasing frequency, increasing combustion temperature, accelerating ceramics/metal liquid-liquid separation and quickening ceramic solidification could not only reduce the average diameter and the size distribution of aligned ZrO2 nano-micron fibers in rod-shaped Al2O3 matrix grains, but also make the randomly-oriented rod-shaped grains finer and increase their aspect ratios. As a result, a remarkable increase in flexural strength and fracture toughness of the ceramics can be observed.

  2. First experiments with the negative ion source NIO1

    Energy Technology Data Exchange (ETDEWEB)

    Cavenago, M., E-mail: cavenago@lnl.infn.it; Fagotti, E.; Minarello, A.; Poggi, M.; Sattin, M. [INFN-Laboratori Nazionali di Legnaro (LNL), v.le dell’Università 2, I-35020 Legnaro PD (Italy); Serianni, G.; Agostinetti, P.; Antoni, V.; Baltador, C.; Barbisan, M.; Baseggio, L.; Bigi, M.; Cervaro, V.; Degli Agostini, F.; Laterza, B.; Maniero, M.; Pasqualotto, R.; Ravarotto, D.; Recchia, M.; Sartori, E. [Consorzio RFX, Corso Stati Uniti 4, I-35127 Padova (Italy); and others

    2016-02-15

    Neutral Beam Injectors (NBIs), which need to be strongly optimized in the perspective of DEMO reactor, request a thorough understanding of the negative ion source used and of the multi-beamlet optics. A relatively compact radio frequency (rf) ion source, named NIO1 (Negative Ion Optimization 1), with 9 beam apertures for a total H{sup −} current of 130 mA, 60 kV acceleration voltage, was installed at Consorzio RFX, including a high voltage deck and an X-ray shield, to provide a test bench for source optimizations for activities in support to the ITER NBI test facility. NIO1 status and plasma experiments both with air and with hydrogen as filling gas are described. Transition from a weak plasma to an inductively coupled plasma is clearly evident for the former gas and may be triggered by rising the rf power (over 0.5 kW) at low pressure (equal or below 2 Pa). Transition in hydrogen plasma requires more rf power (over 1.5 kW)

  3. Uniform magnetic excitations in NiO nanoparticles

    DEFF Research Database (Denmark)

    Bahl, C.R.H.; Kuhn, L.T.; Lefmann, K.

    2006-01-01

    A sample of isolated disc shaped NiO nanoparticles was studied at the RITA-II triple axis spectrometer at SINQ (PSI) using the newly implemented multi-analyser blade imaging mode. The particles were 13 nm in diameter and had a thickness of about 2.5 nm. A non-dispersive spin excitation was observ...... at the antiferromagnetic ((1)/(2) (1)/(2) (1)/(2)) reflection at a scattering vector of kappa = 1.30 angstrom(-1), at an energy of 2 0.51 +/- 0.02 meV. This is shown to be due to uniform magnetic excitations in the nanoparticles. (c) 2006 Elsevier B.V. All rights reserved.......A sample of isolated disc shaped NiO nanoparticles was studied at the RITA-II triple axis spectrometer at SINQ (PSI) using the newly implemented multi-analyser blade imaging mode. The particles were 13 nm in diameter and had a thickness of about 2.5 nm. A non-dispersive spin excitation was observed...

  4. Custom instruction set NIOS-based OFDM processor for FPGAs

    Science.gov (United States)

    Meyer-Bäse, Uwe; Sunkara, Divya; Castillo, Encarnacion; Garcia, Antonio

    2006-05-01

    Orthogonal Frequency division multiplexing (OFDM) spread spectrum technique, sometimes also called multi-carrier or discrete multi-tone modulation, are used in bandwidth-efficient communication systems in the presence of channel distortion. The benefits of OFDM are high spectral efficiency, resiliency to RF interference, and lower multi-path distortion. OFDM is the basis for the European digital audio broadcasting (DAB) standard, the global asymmetric digital subscriber line (ADSL) standard, in the IEEE 802.11 5.8 GHz band standard, and ongoing development in wireless local area networks. The modulator and demodulator in an OFDM system can be implemented by use of a parallel bank of filters based on the discrete Fourier transform (DFT), in case the number of subchannels is large (e.g. K > 25), the OFDM system are efficiently implemented by use of the fast Fourier transform (FFT) to compute the DFT. We have developed a custom FPGA-based Altera NIOS system to increase the performance, programmability, and low power in mobil wireless systems. The overall gain observed for a 1024-point FFT ranges depending on the multiplier used by the NIOS processor between a factor of 3 and 16. A careful optimization described in the appendix yield a performance gain of up to 77% when compared with our preliminary results.

  5. Effects of Co2+ doping on physicochemical behaviors of hierarchical NiO nanostructure

    Science.gov (United States)

    Ding, Caihua; Gao, WenChao; Zhao, Yongjie; Zhao, Yuzhen; Zhou, Heping; Li, Jingbo; Jin, Haibo

    2016-12-01

    A series of Co2+ doped NiO materials (Ni1-xCoxO with x = 0, 0.125, 0.25 and 0.5) were synthesized using a facile hydrothermal method followed by a calcination process. The effects of Co2+ doping on the structural, morphological, magnetic and catalytic properties of NiO were systematically investigated. The results indicated that Co2+ doping would bring about a series influence to the as-obtained NiO product. The XRD results indicated that within the region of 0 ≤ x ≤ 0.25 the doped products revealed a pure NiO phase. The elementary unit for the hierarchy NiO gradually transformed from nanosheets to nanoneedles with the increase of Co2+ doping content. As-obtained Co2+ doped NiO products showed ferromagnetism at room temperature and the magnetization value was increased with the increase of Co2+ doping content. The catalytic properties of NiO concerning the thermal decomposition of ammonium perchlorate (AP) were significantly improved via the introduction of Co2+. The Ni1-xCoxO products with x = 0.25 showed the best catalytic performance to AP, which could decrease the beginning and ending decomposition temperature of AP by 44 and 108 °C. The change of morphology, enhancement of electrical conductivity and the synergistic effect between Co2+ and NiO were the main factors responsible for the improvement of physicochemical behaviors.

  6. Temperature dependence of the magnetization of disc shaped NiO nanoparticles

    DEFF Research Database (Denmark)

    Klausen, Stine Nyborg; Lindgard, P.A.; Lefmann, Kim

    2002-01-01

    as a temperature dependent contribution of a structural peak in contrast to bulk NiO. The two magnetic signals vanish at the same temperature. The data are interpreted on the basis of an extended mean field model on disc shaped NiO particles. This model includes the finite size dependence of the effective field...

  7. The exchange bias effect in Ni/NiO and NiO nanoparticles

    Science.gov (United States)

    Kou, Angela; Feygenson, Mikhail; Kreno, Lauren; Patete, Jonathan; Tiano, Amanda; Zhang, Fen; Wong, Stanislaus; Aronson, Meigan

    2009-03-01

    We used magnetic measurements, X-ray diffraction, and HRTEM to study the exchange bias field in Ni/NiO and NiO nanoparticles made by a modified wet chemistry method. We oxidized re-dispersed powders of bare Ni nanoparticles in air at 400^oC and 900^oC. HRTEM showed that annealing at 900^oC of bare Ni nanoparticles led to the formation of exceptionally high quality NiO nanoparticles, resembling perfect bulk-like crystalline order. To our knowledge, there are no reports of NiO particles of such quality in the literature. The loop shift was 1000 Oe at 300K for the NiO nanoparticles, while it was only 120 Oe at 10K for the Ni/NiO nanoparticles. The difference is explained by the different origins of the loop shift in Ni/NiO and NiO nanoparticles. In Ni/NiO nanoparticles, the loop shift is associated with exchange interactions between ferromagnetic Ni and antiferromagnetic NiO. In NiO nanoparticles, however, the origin of the shift is an uneven number of ferromagnetic sublattices present in NiO nanoparticles, which interact differently with an applied magnetic field (Kodama, 1999).

  8. 基于Nios Ⅱ的双网卡系统设计%Design of Dual Net Card System Based on Nios

    Institute of Scientific and Technical Information of China (English)

    乔从连

    2009-01-01

    针对嵌入式系统领域中网络通讯的安全备份需求特性,以Nios Ⅱ软核处理器为核心,搭配LAN91C111等外围芯片,提出一种基于Nios Ⅱ平台的双网卡系统软硬件设计方案.

  9. Evaluation of interfacial bonding in dissimilar materials of YSZ-alumina composites to 6061 aluminium alloy using friction welding

    Energy Technology Data Exchange (ETDEWEB)

    Uday, M.B., E-mail: ummb2008@gmail.com [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Ahmad Fauzi, M.N., E-mail: afauzi@eng.usm.my [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Zuhailawati, H.; Ismail, A.B. [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia)

    2011-01-25

    Research highlights: {yields} Friction-welding process. {yields} Joining between ceramic composite and metal alloy. {yields} Slip casting of the yttria stabilized zirconia/alumina composite samples. - Abstract: The interfacial microstructures characteristics of alumina ceramic body reinforced with yttria stabilized zirconia (YSZ) was evaluated after friction welding to 6061 aluminum alloy using optical and electron microscopy. Alumina rods containing 25 and 50 wt% yttria stabilized zirconia were fabricated by slip casting in plaster of Paris (POP) molds and subsequently sintered at 1600 deg. C. On the other hand, aluminum rods were machine down to the required dimension using a lathe machine. The diameter of the ceramic and the metal rods was 16 mm. Rotational speeds for the friction welding were varied between 900 and 1800 rpm. The friction pressure was maintained at 7 MPa for a friction time of 30 s. Optical and scanning electron microscopy was used to analyze the microstructure of the resultant joints, particularly at the interface. The joints were also examined with EDX line (energy dispersive X-ray) in order to determine the phases formed during the welding. The mechanical properties of the friction welded YSZ-Al{sub 2}O{sub 3} composite to 6061 alloy were determined with a four-point bend test and Vickers microhardness. The experimental results showed the degree of deformation varied significantly for the 6061 Al alloy than the ceramic composite part. The mechanical strength of friction-welded ceramic composite/6061 Al alloy components were obviously affected by joining rotational speed selected which decreases in strength with increasing rotational speed.

  10. Flower-like NiO structures: Controlled hydrothermal synthesis and electrochemical characteristic

    Energy Technology Data Exchange (ETDEWEB)

    Chai, Hui; Chen, Xuan [Key Laboratory of Clean Energy Material and Technology, Ministry of education, Xinjiang University, Urumqi 830046, Xinjiang (China); Key Laboratory of Advanced Functional Materials, Institute of Applied Chemistry, Xinjiang University, Urumqi 830046, Xinjiang (China); Jia, Dianzeng, E-mail: jdz0991@gmail.com [Key Laboratory of Clean Energy Material and Technology, Ministry of education, Xinjiang University, Urumqi 830046, Xinjiang (China); Key Laboratory of Advanced Functional Materials, Institute of Applied Chemistry, Xinjiang University, Urumqi 830046, Xinjiang (China); Bao, Shujuan [Key Laboratory of Clean Energy Material and Technology, Ministry of education, Xinjiang University, Urumqi 830046, Xinjiang (China); Key Laboratory of Advanced Functional Materials, Institute of Applied Chemistry, Xinjiang University, Urumqi 830046, Xinjiang (China); Zhou, Wanyong [Chemistry and Chemical Engineering of Xinjiang University, Xinjiang University, Urumqi 830046, Xinjiang (China)

    2012-12-15

    Graphical abstract: Flower-like porous NiO was obtained via thermal decomposition of the precursor prepared by a hydrothermal process using hexamethylenetetramine and polyethylene glycol as hydrolysis-controlling agent and surfactant, respectively. The morphology and microstructure of as-synthesized NiO were characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results of electrochemical measurements demonstrated that the flower-like porous NiO has high capacity (340 F g{sup −1}) with excellent cycling performance as electrode materials of electrochemical capacitors (ECs), which may be attributed to the unique microstrcture of NiO. Data analyses indicated that NiO with novel porous structure attractive for practical and large-scale applications in electrochemical capacitors. Display Omitted Highlights: ► Synthesis and characterization of NiO with novel porous structure is presented in this work. ► The electrochemical performance of product was examined. ► NiO with excellent performance as electrode materials may be due to the unique microstrcture. ► NiO with novel porous structure attractive for practical with high capacity (340 F g{sup −1}). -- Abstract: Flower-like porous NiO was obtained by thermal decomposition of the precursor prepared by a hydrothermal process with hexamethylenetetramine and polyethylene glycol as hydrolysis-controlling agent and surfactant, respectively. The morphology and microstructure of as-synthesized NiO were characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The resulting structures of NiO exhibited porous like petal building blocks. The electrochemical measurements’ results demonstrated that flower-like porous NiO has high capacity (340 F g{sup −1}) with excellent cycling performance as electrode materials for

  11. Synthesis of hierarchical flower-like NiO and the influence of surfactant

    Science.gov (United States)

    Liu, Shilin; Zeng, Wen; Chen, Ting

    2017-01-01

    The NiO nanoflowers were prepared by a facile surfactant assisted hydrothermal method using Ni(NO3)2-6H2O or NiCl2-6H2O as precursor compound. The microstructure of the samples was characterized by SEM and XRD. The gas sensing properties of the NiO nanoflowers toward ethanol was also investigated. The results show that surfactant plays a key role in the synthesis of flower-like NiO. The NiO nanoflowers show excellent sensing performances to ethanol gas. This morphology holds substantial promise for applying NiO as a potential gas sensing material for future sensor application.

  12. Preparation and characterization of fibrous NiO particles by thermal decomposition of nickelous complex precursors

    Institute of Scientific and Technical Information of China (English)

    张传福; 湛菁; 邬建辉; 黎昌俊

    2004-01-01

    The influences of pyrolytic conditions, including temperature, time, the flow rate of air, and the heating rate, on the morphology, average size and specific surface area of the NiO particles were investigated, and the composition and morphologies of the products were characterized by using of XRD, SEM and BET. It is found that fibrous NiO particles were produced under the optimal conditions. A suitable range of pH for preparing dispersive precursors was chosen according to analysis of zeta potential. Based on the observations of NiO precursors growth and SEM morphology of the precursor, the oriented attachment was proposed for the well-aligned growth of the NiO precursor fibres. The final product NiO inherits the morphology of the precursor.

  13. Facile synthesis of self-assembled biporous NiO and its electrochemical properties

    Science.gov (United States)

    Muruganandham, M.; Suri, Rominder P. S.; Sillanpää, Mika; Lee, Gang-Juan; Wu, Jerry J.

    2016-09-01

    In this article, we report the synthesis of self-assembled bi-porous nickel oxide on a large scale without using any templates or matrix. Porous NiO microspheres composed of particles were obtained by thermal decomposition of nickel oxalate, which was prepared using nickel salt and oxalic acid as precursors. The as-obtained nickel oxalate and nickel oxide were characterized using X-ray powder diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), thermogravimetric analysis (TGA), and nitrogen adsorption-desorption analysis. The influence of various experimental conditions on the formation nickel oxalate and NiO were studied. The nitrogen adsorption-desorption analysis showed that the synthesized NiO possesses a biporous (both mesoporous and macroporous) surface structur. The NiO microspheres showed a discharge capacity of 2929 mAh g-1. A plausible mechanism for the NiO self-assembly was proposed.

  14. Core-level electronic properties of nanostructured NiO coatings

    Energy Technology Data Exchange (ETDEWEB)

    Palacin, S. [Departamento de Fisica Aplicada, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Gutierrez, A. [Departamento de Fisica Aplicada, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain)], E-mail: a.gutierrez@uam.es; Preda, I.; Hernandez-Velez, M. [Departamento de Fisica Aplicada, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Sanz, R. [Instituto de Ciencia de Materiales, CSIC, Cantoblanco, 28049 Madrid (Spain); Jimenez, J.A. [Centro Nacional de Investigaciones Metalurgicas, CSIC, Av. Gregorio del Amo 8, 28040 Madrid (Spain); Soriano, L. [Departamento de Fisica Aplicada, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain)

    2007-10-31

    Nanostructured NiO films with different thicknesses were grown on nanoporous alumina membrane substrates by reactive evaporation of Ni in an oxygen atmosphere. The reactive deposition process was assisted by a low energy oxygen ion-beam in order to increase the NiO input into the pores. Surface morphology and structure of the films were analyzed by SEM and XPS. SEM observations reveal a well adhered film of NiO on the substrate. This film appears to be uniform and presents a rather irregular nanostructured morphology, built of NiO clusters with sizes ranging between 5 and 30 nm. The core-level electronic properties of this nanostructured NiO film result to be similar to those of an ultrathin film about one monolayer thick. This behaviour can be explained by the large surface to volume ratio of both systems.

  15. Metal oxides modified NiO catalysts for oxidative dehydrogenation of ethane to ethylene

    KAUST Repository

    Zhu, Haibo

    2014-06-01

    The sol-gel method was applied to the synthesis of Zr, Ti, Mo, W, and V modified NiO based catalysts for the ethane oxidative dehydrogenation reaction. The synthesized catalysts were characterized by XRD, N2 adsorption, SEM and TPR techniques. The results showed that the doping metals could be highly dispersed into NiO domains without the formation of large amount of other bulk metal oxide. The modified NiO materials have small particle size, larger surface area, and higher reduction temperature in contrast to pure NiO. The introduction of group IV, V and VI transition metals into NiO decreases the catalytic activity in ethane ODH. However, the ethylene selectivity is enhanced with the highest level for the Ni-W-O and Ni-Ti-O catalysts. As a result, these two catalysts show improved efficiency of ethylene production in the ethane ODH reaction. © 2014 Elsevier B.V. All rights reserved.

  16. Low Absorption Vitreous Carbon Reactors for Operando XAS: A Case Study on Cu/Zeolites for Selective Catalytic Reduction of NOx by NH3

    Energy Technology Data Exchange (ETDEWEB)

    Kispersky, Vincent F.; Kropf, Jeremy; Ribeiro, Fabio H; Miller, Jeffrey T

    2012-01-01

    We describe the use of vitreous carbon as an improved reactor material for an operando X-ray absorption spectroscopy (XAS) plug-flow reactor. These tubes significantly broaden the operating range for operando experiments. Using selective catalytic reduction (SCR) of NOx by NH₃ on Cu/Zeolites (SSZ-13, SAPO-34 and ZSM-5) as an example reaction, we illustrate the high-quality XAS data achievable with these reactors. The operando experiments showed that in Standard SCR conditions of 300 ppm NO, 300 ppm NH₃, 5% O₂, 5% H₂O, 5% CO₂ and balance He at 200 °C, the Cu was a mixture of Cu(I) and Cu(II) oxidation states. XANES and EXAFS fitting found the percent of Cu(I) to be 15%, 45% and 65% for SSZ-13, SAPO-34 and ZSM-5, respectively. For Standard SCR, the catalytic rates per mole of Cu for Cu/SSZ-13 and Cu/SAPO-34 were about one third of the rate per mole of Cu on Cu/ZSM-5. Based on the apparent lack of correlation of rate with the presence of Cu(I), we propose that the reaction occurs via a redox cycle of Cu(I) and Cu(II). Cu(I) was not found in in situSCR experiments on Cu/Zeolites under the same conditions, demonstrating a possible pitfall of in situ measurements. A Cu/SiO₂ catalyst, reduced in H₂ at 300 °C, was also used to demonstrate the reactor's operando capabilities using a bending magnet beamline. Analysis of the EXAFS data showed the Cu/SiO₂ catalyst to be in a partially reduced Cu metal–Cu(I) state. In addition to improvements in data quality, the reactors are superior in temperature, stability, strength and ease of use compared to previously proposed borosilicate glass, polyimide tubing, beryllium and capillary reactors. The solid carbon tubes are non-porous, machinable, can be operated at high pressure (tested at 25 bar), are inert, have high material purity and high X-ray transmittance.

  17. Low absorption vitreous carbon reactors for operando XAS: a case study on Cu/Zeolites for selective catalytic reduction of NO(x) by NH3.

    Science.gov (United States)

    Kispersky, Vincent F; Kropf, A Jeremy; Ribeiro, Fabio H; Miller, Jeffrey T

    2012-02-21

    We describe the use of vitreous carbon as an improved reactor material for an operando X-ray absorption spectroscopy (XAS) plug-flow reactor. These tubes significantly broaden the operating range for operando experiments. Using selective catalytic reduction (SCR) of NO(x) by NH(3) on Cu/Zeolites (SSZ-13, SAPO-34 and ZSM-5) as an example reaction, we illustrate the high-quality XAS data achievable with these reactors. The operando experiments showed that in Standard SCR conditions of 300 ppm NO, 300 ppm NH(3), 5% O(2), 5% H(2)O, 5% CO(2) and balance He at 200 °C, the Cu was a mixture of Cu(I) and Cu(II) oxidation states. XANES and EXAFS fitting found the percent of Cu(I) to be 15%, 45% and 65% for SSZ-13, SAPO-34 and ZSM-5, respectively. For Standard SCR, the catalytic rates per mole of Cu for Cu/SSZ-13 and Cu/SAPO-34 were about one third of the rate per mole of Cu on Cu/ZSM-5. Based on the apparent lack of correlation of rate with the presence of Cu(I), we propose that the reaction occurs via a redox cycle of Cu(I) and Cu(II). Cu(I) was not found in in situ SCR experiments on Cu/Zeolites under the same conditions, demonstrating a possible pitfall of in situ measurements. A Cu/SiO(2) catalyst, reduced in H(2) at 300 °C, was also used to demonstrate the reactor's operando capabilities using a bending magnet beamline. Analysis of the EXAFS data showed the Cu/SiO(2) catalyst to be in a partially reduced Cu metal-Cu(I) state. In addition to improvements in data quality, the reactors are superior in temperature, stability, strength and ease of use compared to previously proposed borosilicate glass, polyimide tubing, beryllium and capillary reactors. The solid carbon tubes are non-porous, machinable, can be operated at high pressure (tested at 25 bar), are inert, have high material purity and high X-ray transmittance.

  18. Elucidating and exploiting the chemistry of Keggin heteropolyacids in the methanol-to-DME conversion: enabling the bulk reaction thanks to operando Raman

    OpenAIRE

    Schnee, Josefine; Eric M. Gaigneaux

    2017-01-01

    Operando Raman spectroscopy is used here to enlighten crucial and yet unconsidered aspects of the catalytic behavior of Keggin heteropolyacids (HPAs) in the gas phase dehydration of methanol to dimethylether (DME). On one hand, HPAs are since a long time claimed as being able to absorb methanol into their bulk, but on the other hand this feature is not yet really exploited when it comes to develop/use HPA-based catalysts for the methanol-to-DME process. Actually, the conditions in which the b...

  19. Desempenho de gotejadores operando com efluente da castanha de caju sob distintas pressões de serviço

    Directory of Open Access Journals (Sweden)

    Ketson Bruno da Silva

    2013-06-01

    Full Text Available Este trabalho objetivou analisar o efeito de distintas pressões de serviço no coeficiente de variação da vazão (CVQ de sistemas de irrigação por gotejamento, operando com água residuária da castanha de caju. O experimento foi montado no esquema de parcelas subsubdivididas, tendo, nas parcelas, as pressões de serviço (70, 140, 210 e 280 kPa, nas subparcelas, os modelos de gotejadores (G1, G2 e G3 e, nas subsubparcelas, os períodos das avaliações (0, 20, 40, 60, 80, 100, 120, 140 e 160 horas, no delineamento inteiramente casualizado, com três repetições. O CVQ das unidades de irrigação, bem como as características físico-químicas da água residuária, foram determinados a cada 20 h, até completar o tempo de operação de 160 h. Os resultados indicaram que a água residuária da castanha de caju representa risco de obstrução de gotejadores, em relação às características pH, cálcio, magnésio, manganês e sólidos suspensos. O entupimento parcial dos gotejadores acarretou aumento do CVQ, nas unidades de irrigação; e as unidades de irrigação que funcionaram na pressão de serviço P1 (70 kPa apresentaram maior nível de entupimento de gotejadores, em relação às demais, em função da menor velocidade de escoamento de efluente no interior dos emissores.

  20. Corrosion chemistry closing comments: opportunities in corrosion science facilitated by operando experimental characterization combined with multi-scale computational modelling.

    Science.gov (United States)

    Scully, John R

    2015-01-01

    Recent advances in characterization tools, computational capabilities, and theories have created opportunities for advancement in understanding of solid-fluid interfaces at the nanoscale in corroding metallic systems. The Faraday Discussion on Corrosion Chemistry in 2015 highlighted some of the current needs, gaps and opportunities in corrosion science. Themes were organized into several hierarchical categories that provide an organizational framework for corrosion. Opportunities to develop fundamental physical and chemical data which will enable further progress in thermodynamic and kinetic modelling of corrosion were discussed. These will enable new and better understanding of unit processes that govern corrosion at the nanoscale. Additional topics discussed included scales, films and oxides, fluid-surface and molecular-surface interactions, selected topics in corrosion science and engineering as well as corrosion control. Corrosion science and engineering topics included complex alloy dissolution, local corrosion, and modelling of specific corrosion processes that are made up of collections of temporally and spatially varying unit processes such as oxidation, ion transport, and competitive adsorption. Corrosion control and mitigation topics covered some new insights on coatings and inhibitors. Further advances in operando or in situ experimental characterization strategies at the nanoscale combined with computational modelling will enhance progress in the field, especially if coupling across length and time scales can be achieved incorporating the various phenomena encountered in corrosion. Readers are encouraged to not only to use this ad hoc organizational scheme to guide their immersion into the current opportunities in corrosion chemistry, but also to find value in the information presented in their own ways.

  1. Operando atomic structure and active sites of TiO2(110)-supported gold nanoparticles during carbon monoxide oxidation.

    Science.gov (United States)

    Saint-Lager, Marie-Claire; Laoufi, Issam; Bailly, Aude

    2013-01-01

    It is well known that gold nanoparticles supported on TiO2 act as a catalyst for CO oxidation, even below room temperature. Despite extensive studies, the origin of this catalytic activity remains under debate. Indeed, when the particle size decreases, many changes may occur; thus modifying the nanoparticles' electronic properties and consequently their catalytic performances. Thanks to a state-of-the-art home-developed setup, model catalysts can be prepared in ultra-high vacuum and their morphology then studied in operando conditions by Grazing Incidence Small Angle X-ray Scattering, as well as their atomic structure by Grazing Incidence X-ray Diffraction as a function of their catalytic activity. We previously reported on the existence of a catalytic activity maximum observed for three-dimensional gold nanoparticles with a diameter of 2-3 nm and a height of 6-7 atomic planes. In the present work we correlate this size dependence of the catalytic activity to the nanoparticles' atomic structure. We show that even when their size decreases below the optimum diameter, the gold nanoparticles keep the face-centered cubic structure characteristic of bulk gold. Nevertheless, for these smallest nanoparticles, the lattice parameter presents anisotropic strains with a larger contraction in the direction perpendicular to the surface. Moreover a careful analysis of the atomic-scale morphology around the catalytic activity maximum tends to evidence the role of sites with a specific geometry at the interface between the nanoparticles and the substrate. This argues for models where atoms at the interface periphery act as catalytically active sites for carbon monoxide oxidation.

  2. Análisis exergético de una planta de cogeneración operando bajo ciclo combinado

    Directory of Open Access Journals (Sweden)

    Hernán Darío Patiño Duque

    2017-01-01

    Full Text Available En la actualidad, hay diversas formas para generar energía eléctrica, una de ellas consiste en aprovechar la cantidad de energía liberada al quemar un combustible y efectuar una serie de procesos de conversión de energía mediante un ciclo termodinámico. Para hacer estos procesos más eficientes, existen herramientas que permiten analizar en qué equipos de la planta se está desaprovechando energía, una de estas técnicas es el análisis exergético, que consiste en la aplicación simultanea de la primera y segunda ley de la termodinámica. En el presente trabajo se realiza el análisis exergético a una planta de generación de electricidad y calor a partir de la producción de vapor operando bajo un ciclo combinado. Inicialmente se definen conceptos importantes para realizar el análisis. Después de aplicar la primera y segunda ley de la termodinámica los resultados indican que la eficiencia exergética de la planta de ciclo combinado es 53% y se encuentra que la cámara de combustión es el componente del sistema que más exergía destruye y que las bombas son los dispositivos donde hay menor pérdida de energía útil.

  3. Operando Solid-State NMR Observation of Solvent-Mediated Adsorption-Reaction of Carbohydrates in Zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Long; Alamillo, Ricardo; Elliott, William A.; Andersen, Amity; Hoyt, David W.; Walter, Eric D.; Han, Kee Sung; Washton, Nancy M.; Rioux, Robert M.; Dumesic, James A.; Scott, Susannah L.

    2017-03-31

    In the liquid-phase catalytic processing of molecules using heterogeneous catalysts - an important strategy for obtaining renewable chemicals from biomass - many of the key reactions occur at solid-liquid interfaces. In particular, glucose isomerization occurs when the glucose is adsorbed in the micropores of a zeolite catalyst. Since solvent molecules are coadsorbed, the catalytic activity depends strongly and often nonmonotonically on the solvent composition. For glucose isomerization catalyzed by NaX and NaY zeolites, there is an initial steep decline when water is mixed with a small amount of the organic cosolvent γ-valerolactone (GVL), followed by a dramatic and surprising recovery as the GVL content in the mixed solvent increases. Here we elucidate the origin of this complex solvent effect using operando solid-state NMR spectroscopy. The glucopyranose tautomers immobilized in the zeolite pores were observed and their transformations into fructose and mannose followed in real time. The microheterogeneity of the solvent system, manifested by a nonmonotonic trend in the mixing enthalpy, influences the mobility and adsorption behavior of the carbohydrates, water, and GVL, which were studied using pulsed-field gradient (PFG) NMR diffusivity measurements. At low GVL concentrations, glucose is depleted in the zeolite pores relative to the solution phase and changes in the local structure of coadsorbed water serve to further suppress the isomerization rate. At higher GVL concentrations, this lower intrinsic reactivity is largely compensated by strong glucose partitioning into the pores, resulting in dramatic (up to 32×) enhancements in the local sugar concentration at the solid-liquid interface.

  4. In operando neutron diffraction study of LaNdMgNi9H13 as a metal hydride battery anode

    Science.gov (United States)

    Nazer, N. S.; Denys, R. V.; Yartys, V. A.; Hu, Wei-Kang; Latroche, M.; Cuevas, F.; Hauback, B. C.; Henry, P. F.; Arnberg, L.

    2017-03-01

    La2MgNi9-related alloys are superior metal hydride battery anodes as compared to the commercial AB5 alloys. Nd-substituted La2-yNdyMgNi9 intermetallics are of particular interest because of increased diffusion rate of hydrogen and thus improved performance at high discharge currents. The present work presents in operando characterization of the LaNdMgNi9 intermetallic as anode for the nickel metal hydride (Ni-MH) battery. We have studied the structural evolution of LaNdMgNi9 during its charge and discharge using in situ neutron powder diffraction. The work included experiments using deuterium gas and electrochemical charge-discharge measurements. The alloy exhibited a high electrochemical discharge capacity (373 mAh/g) which is 20% higher than the AB5 type alloys. A saturated β-deuteride synthesized by solid-gas reaction at PD2 = 1.6 MPa contained 12.9 deuterium atoms per formula unit (D/f.u.) which resulted in a volume expansion of 26.1%. During the electrochemical charging, the volume expansion (23.4%) and D-contents were found to be slightly reduced. The reversible electrochemical cycling is performed through the formation of a two-phase mixture of the α-solid solution and β-hydride phases. Nd substitution contributes to the high-rate dischargeability, while maintaining a good cyclic stability. Electrochemical Impedance Spectroscopy (EIS) was used to characterize the anode electrode on cycling. A mathematical model for the impedance response of a porous electrode was utilized. The EIS showed a decreased hydrogen transport rate during the long-term cycling, which indicated a corresponding slowing down of the electrochemical processes at the surface of the metal hydride anode.

  5. 氢电极预烧温度对丝网印刷YSZ电解质薄膜的影响%Effect of Presintering Temperature of Hydrogen Electrode on Screen-Printed YSZ Films

    Institute of Scientific and Technical Information of China (English)

    梁明德; 章德铭; 张鑫; 冀晓娟; 沈婕; 任先京

    2013-01-01

    Yttria-stabilized zirconia (YSZ) electrolyte film was prepared by screen-printing technology. The presintering temperature of porous NiO-YSZ hydrogen electrode substrates used in solid oxide electrolysis cells (SOEC) was optimized. A single fuel cell of Ni-YSZ/YSZ (10 μm)/LSM-YSZ was successfully prepared by screen-printing method. The results show that the optimum presintering temperature of NiO-YSZ hydrogen electrode is 1 000 ℃, and the hydrogen production rate of single SOEC is 386 mL/(cm2 · h) , 255 mL/(cm2 · h) , and 142 mL/(cm2 · h), at 800 ℃ , 850 ℃ and 900 ℃ , respectively. The ohmic resistance of the electrolytic cell can be effectively reduced through thinning down of YSZ electrolyte membrane with screen-printing technology.%采用丝网印刷法制备了Y2O3稳定ZrO2(YSZ)电解质薄膜,并对固体氧化物电解池(SOEC)的NiO-YSZ氢电极预烧温度进行了优化.结果表明,NiO-YSZ氢电极适宜的预烧温度为1000℃,YSZ电解质薄膜化后制备的SOEC在800℃、850℃和900℃三种电解温度下,1.50 V时的产氢速率分别为386 mL/(cm2·h)、255 mL/(cm2·h)和142 mL/(cm2·h).采用丝网印刷法将YSZ电解质薄膜化制备后可以有效降低电解池的欧姆阻抗.

  6. Dielectric constant of NiO and LDA+U

    Science.gov (United States)

    Ye, Lin-Hui; Luo, Ning; Peng, Lian-Mao; Weinert, M.; Freeman, A. J.

    2013-02-01

    The local density approximation (LDA) and generalized gradient approximations (GGA) of density functional theory systematically overestimate the electronic polarizability of materials. We calculate the dielectric constant of NiO by the direct method and find, contrary to previous suggestions, that the LDA+U method reduces the polarization such that ɛ∞ decreases monotonically with increasing U. We illustrate the existence of a linear term in the effective exchange-correlation potential that counteracts the external electric field, thus demonstrating that the decrease of ɛ∞ is intrinsic to the LDA+U correction. The reduction of the polarization is due mostly to reduced orbital mixing between the unoccupied eg states and the occupied 2p states. Our work establishes LDA+U as a viable method for calculating the dielectric constants of correlated materials.

  7. Enhanced magnetic properties of NiO powders by the mechanical activation of aluminothermic reduction of NiO prepared by a ball milling process

    Science.gov (United States)

    Padhan, Aneeta Manjari; Ravikumar, P.; Saravanan, P.; Alagarsamy, Perumal

    2016-11-01

    We report the effect of mechanical activation on NiO-Al (x wt%) reduction reaction and resulting structural and magnetic properties by carrying out high-energy planetary ball milling. The pure NiO (un-milled) and milled NiO-Al (x≤2.5) powders exhibit face centered cubic structure, but the antiferromagnetic nature of pure NiO powder shows significant room temperature ferromagnetism with moderate moment and coercivity after milling due to non-stoichiometry in NiO caused by the defects, size reduction and oxidation of Ni. On the other hand, the addition of Al between 2.5 and 10% in NiO forms solid solution of NiO-Al with considerable reduction in the moment due to the atomic disorder. With increasing Al above 10%, NiO reduction reaction progresses gradually and as a result, the average magnetization increases from 0.57 to 4.3 emu/g with increasing Al up to 25%. A maximum of 91% reduction was observed for NiO-Al (40%) powders in 30 h of milling with a large increase in magnetization (~24 emu/g) along with the development of α-Al2O3. Thermomagnetization data reveal the presence of mixed magnetic phases in milled NiO powders and the component of induced ferromagnetic phase fades out with increasing Al due to the formation of Ni from the NiO-Al reduction reaction. The changes in the structural and magnetic properties are discussed on the basis of mechanical activation on the reduction of NiO by Al. The controlled reduction reaction with different Al content in NiO-Al is encouraging for the applications in catalysis and process of ore reduction.

  8. Facile synthesis and electron transport properties of NiO nanostructures investigated by scanning tunneling microscopy

    Directory of Open Access Journals (Sweden)

    Govind Mallick

    2017-08-01

    Full Text Available Due to their unique chemical, thermal, electronic and photonic properties, low -dimensional transition metal oxides, especially NiO, have attracted great deal of attention for potential applications in a wide range of technologies, such as, sensors, electrochromic coatings and self-healing materials. However, their synthesis involves multi-step complex procedures that in addition to being expensive, further introduce impurities. Here we present a low cost facile approach to synthesize uniform size NiO nanoparticles (NPs from hydrothermally grown Ni(OH2. Detailed transmission electron microscopic analysis reveal the average size of NiO NPs to be around 29 nm. The dimension of NiO NP is also corroborated by the small area scanning tunneling microscope (STM measurements. Further, we investigate electron transport characteristics of newly synthesized Ni(OH2 and NiO nanoparticles on p-type Si substrate using scanning tunneling microscopy. The conductivity of Ni(OH2 and NiO are determined to be 1.46x10-3 S/cm and 2.37x10-5 S/cm, respectively. The NiO NPs exhibit a lower voltage window (∼0.7 V electron tunneling than the parent Ni(OH2.

  9. Efficient photoelectrochemical water splitting over anodized p-type NiO porous films.

    Science.gov (United States)

    Hu, Chenyan; Chu, Kenneth; Zhao, Yihua; Teoh, Wey Yang

    2014-11-12

    NiO photocathodes were fabricated by alkaline etching-anodizing nickel foil in an organic-based electrolyte. The resulting films have a highly macroporous surface structure due to rapid dissolution of the oxide layer as it is formed during the anodization process. We are able to control the films' surface structures by varying the anodization duration and voltage. With an onset potential of +0.53 V versus the reversible hydrogen electrode (RHE), the photocurrent efficiency of the NiO electrodes showed dependencies on their surface roughness factor, which determines the extent of semiconductor-electrolyte interface and the associated quality of the NiO surface sites. A maximum incident photon-to-current conversion efficiency (IPCE(max)) of 22% was obtained from NiO film with a roughness factor of 8.4. Adding an Al2O3 blocking layer minimizes surface charge recombination on the NiO and hence increased the IPCE(max) to 28%. The NiO/Al2O3 films were extremely stable during photoelectrochemical water splitting tests lasting up to 20 h, continuously producing hydrogen and oxygen in the stoichiometric 2:1 ratio. The NiO/Al2O3 and NiO films fabricated using the alkaline anodization process produced 12 and 6 times as much hydrogen, respectively, as those fabricated using commercial NiO nanoparticles.

  10. Effect of annealing on the magnetic properties of ball milled NiO powders

    Energy Technology Data Exchange (ETDEWEB)

    Kisan, Bhagaban [Department of Physics, Indian Institute of Technology Guwahati, Guwahati 781039 (India); Saravanan, P. [Defence Metallurgical Research laboratory, Hyderabad 500058 (India); Layek, Samar; Verma, H.C. [Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208016 (India); Hesp, David; Dhanak, Vinod [Department of Physics, University of Liverpool, Liverpool L69 3BX (United Kingdom); Krishnamurthy, Satheesh [Materials Engineering, The Open University, Milton Keynes MK7 6AA (United Kingdom); Perumal, A., E-mail: perumal@iitg.ernet.in [Department of Physics, Indian Institute of Technology Guwahati, Guwahati 781039 (India)

    2015-06-15

    We report systematic investigations on structural and magnetic properties of nanosized NiO powders prepared by the ball milling process followed by systematic annealing at different temperatures. Both as-milled and annealed NiO powders exhibit face centered cubic structure, but average crystallite size decreases (increases) with increasing milling time (annealing temperature). Pure NiO exhibits antiferromagnetic nature, which transforms into ferromagnetic one with moderate moment at room temperature with decreasing crystallite size. The on-set of ferromagnetic behavior in the as-milled powders was observed at higher temperatures (>750 K) as compared to bulk Ni (~630 K). On the other hand, annealing of as-milled powders showed a large reduction in magnetic moment and the rate of decrease of moment strongly depends on the milling conditions. The observed properties are discussed on the basis of crystallite size variation, defect density, oxidation/reduction of Ni and interaction between uncompensated surfaces and particle core with lattice expansion. - Highlights: • Preparation of fine NiO powder using top-to-bottom approach using planetary ball mill. • Effect of milling on instituting room temperature ferromagnetism with size reduction. • Stability of ferromagnetic properties at high temperatures in milled NiO powders • Effect of annealing process on the structural properties of milled NiO powders. • Understanding the origin of ferromagnetism at 300 K in NiO powders through annealing.

  11. Investigation of the properties of In doped NiO films

    Energy Technology Data Exchange (ETDEWEB)

    Kerli, S., E-mail: suleymankerli@yahoo.com [Kahramanmaras Sutcu Imam University, Department of Physics, 46100 Kahramanmaras (Turkey); Alver, U. [Kahramanmaras Sutcu Imam University, Department of Physics, 46100 Kahramanmaras (Turkey); Yaykaşlı, H. [Research and Development Center for University-Industry and Public Relations (USKIM), 46100 Kahramanmaras (Turkey)

    2014-11-01

    Highlights: • Indium doped NiO films were synthesized using nickel nitrate hexahydrate precursors via the airbrush spraying method. • Indium doping affects the morphologies, crystal structures and optical properties of the films. • Indium doped NiO films change in electrical resistivity. - Abstract: NiO and Indium doped (3, 5, 8 and 10 at%) NiO thin films were produced on glass substrates at 400 °C by airbrush spraying method using a solution of nickel nitrate hexahydrate. The effect of Indium (In) concentration on the structural, optical and transport properties of NiO thin films was studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), spectral transmittance and linear four-probe resistivity. From The X-ray diffraction pattern, it is observed that pure, 3% and 5 at% In doped NiO films have a cubic structure, but 8 and 10 at% doped films have an amorphous structure. Optical measurements show that the band gap energies of the films vary with indium concentrations. Moreover, It has been observed that the doping of NiO films with In increases the electrical resistivity.

  12. High-temperature mechanical characteristics of NiO/3YTZP composites

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez-Melendo, M., E-mail: melendo@us.es [Departamento de Fisica de la Materia Condensada and Instituto de Ciencia de Materiales (Universidad de Sevilla-CSIC), Aptdo, 1065, 41080 Sevilla (Spain); Oliva-Ramirez, M.; Huaman-Mamani, F.A. [Departamento de Fisica de la Materia Condensada and Instituto de Ciencia de Materiales (Universidad de Sevilla-CSIC), Aptdo, 1065, 41080 Sevilla (Spain)

    2012-09-25

    Highlights: Black-Right-Pointing-Pointer Fabrication of 40 mol% NiO/3 mol% Y{sub 2}O{sub 3}-stabilized tetragonal ZrO{sub 2} (3YTZP) composites. Black-Right-Pointing-Pointer Duplex microstructure of fine (zirconia) and coarse (NiO) grains. Black-Right-Pointing-Pointer Mechanical behavior controlled by the zirconia phase. Black-Right-Pointing-Pointer Grain boundary sliding is the dominant deformation mechanism. - Abstract: NiO/3YTZP (3 mol% Y{sub 2}O{sub 3}-stabilized tetragonal ZrO{sub 2}) composites with 40 mol% NiO (26 vol% NiO) have been fabricated by mechanical mixing of NiO and 3YTZP powders and sintering at 1500 Degree-Sign C for 10 h in air. The resulting microstructures have been characterized by electron microscopy. Compressive mechanical tests at constant strain rate were conducted on these materials at temperatures between 1150 and 1350 Degree-Sign C in air. The {sigma}-{epsilon} curves display extended secondary creep regimes without signals of macroscopic failure. The composite creep behavior is characterized by a stress exponent n = 2 and an activation energy for flow Q = 490 kJ/mol. The overall creep behavior of the composites is essentially controlled by the zirconia matrix, due to the softness of the NiO phase in the experimental conditions used in this study.

  13. Synthesis, Characterization, and Magnetic Properties of Pure and EDTA-Capped NiO Nanosized Particles

    Directory of Open Access Journals (Sweden)

    H. T. Rahal

    2017-01-01

    Full Text Available The effect of ethylenediaminetetraacetic acid (EDTA as a capping agent on the structure, morphology, optical, and magnetic properties of nickel oxide (NiO nanosized particles, synthesized by coprecipitation method, was investigated. Nickel chloride hexahydrate and sodium hydroxide (NaOH were used as precursors. The resultant nanoparticles were characterized by X-ray diffraction (XRD, transmission electron microscopy (TEM, and scanning electron microscopy (SEM. XRD patterns showed that NiO have a face-centered cubic (FCC structure. The crystallite size, estimated by Scherrer formula, has been found in the range of 28–33 nm. It is noticed that EDTA-capped NiO nanoparticles have a smaller size than pure nanoparticles. Thus, the addition of 0.1 M capping agent EDTA can form a nucleation point for nanoparticles growth. The optical and magnetic properties were investigated by Fourier transform infrared spectroscopy (FTIR and UV-vis absorption spectroscopy (UV as well as electron paramagnetic resonance (EPR and magnetization measurements. FTIR spectra indicated the presence of absorption bands in the range of 402–425 cm−1, which is a common feature of NiO. EPR for NiO nanosized particles was measured at room temperature. An EPR line with g factor ≈1.9–2 is detected for NiO nanoparticles, corresponding to Ni2+ ions. The magnetic hysteresis of NiO nanoparticles showed that EDTA capping recovers the surface magnetization of the nanoparticles.

  14. Solvothermal synthesis and photocatalytic properties of NiO ultrathin nanosheets with porous structure

    Energy Technology Data Exchange (ETDEWEB)

    Qing, Zhang; Haixia, Liu; Huali, Li; Yu, Liu; Huayong, Zhang; Tianduo, Li, E-mail: litianduo@163.com

    2015-02-15

    Highlights: • Hierarchical NiO microspheres with ultrathin and porous structure were prepared by solvothermal method. • The nanoparticles were grown by the constant direction with the preferred orientation. • Structural features of NiO microspheres were characterized by means of different techniques. • High temperature annealing processing conducive to the formation of the porous feature. • NiO microspheres had better photocatalytic activity and stable cyclability for methylene blue dye under UV irradiation than commercial NiO. - Abstract: Hierarchical NiO microspheres, composed of ultrathin nanosheets with porous structure, are prepared through a facile solvothermal route followed by a calcination process. First, the precursor Ni{sub 3}(NO{sub 3}){sub 2}(OH){sub 4} hierarchical architectures assembled by irregular nanosheets were synthesized through urea assisted precipitation. Second, the NiO hierarchical architecture was obtained from the precursor by a simple calcination procedure without changing their morphologies. The resultant products were characterized by XRD, SEM, TEM, TG, FT-IR and BET analysis techniques. The XRD pattern showed that the sample exhibited a rocksalt cubic phase structure after calcined at 500 °C for 2 h. The SEM and TEM images demonstrated that the as-prepared NiO were microspheres composed of ultrathin nanosheets with porous structure. The catalytic efficiency of the NiO nanomaterials is evaluated by the photocatalytic degradation of methylene blue (MB). The obtained NiO displayed the excellent degradable ability and stable cyclability to MB dye, which may be attributed to its unique hierarchical characteristics: ultrathin-porous microstructure.

  15. Bridging exchange bias effect in NiO and Ni(core)@NiO(shell) nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Rinaldi-Montes, Natalia, E-mail: nataliarin@gmail.com [Departamento de Física, Universidad de Oviedo, E-33007 Oviedo (Spain); Gorria, Pedro [Departamento de Física & IUTA, EPI, Universidad de Oviedo, E-33203 Gijón (Spain); Martínez-Blanco, David [Servicios Científico-Técnicos, Universidad de Oviedo, E-33006 Oviedo (Spain); Fuertes, Antonio B. [Instituto Nacional del Carbón, CSIC, E-33080 Oviedo (Spain); Fernández Barquín, Luis [CITIMAC, Facultad de Ciencias, Universidad de Cantabria, E-39005 Santander (Spain); Puente-Orench, Inés [Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza and Institut Laue-Langevin, BP 156, F-38042 Grenoble Cedex 9 (France); Blanco, Jesús A. [Departamento de Física, Universidad de Oviedo, E-33007 Oviedo (Spain)

    2016-02-15

    Among all bi-magnetic core(transition metal)@shell(transition metal oxide) nanoparticles (NPs), Ni@NiO ones show an onset temperature for the exchange bias (EB) effect far below the Néel temperature of bulk antiferromagnetic NiO. In this framework, the role played by the magnetism of NiO at the nanoscale is investigated by comparing the microstructure and magnetic properties of NiO and Ni@NiO NPs. With the aim of bridging the two systems, the diameter of the NiO NPs (~4 nm) is chosen to be comparable to the shell thickness of Ni@NiO ones (~2 nm). The EB effect in Ni@NiO NPs is attributed to the exchange coupling between the core and the shell, with an interfacial exchange energy of ΔE~0.06 erg cm{sup −2}, thus comparable to previous reports on Ni/NiO interfaces both in thin film and NP morphologies. In contrast, the EB detected in NiO NPs is explained in a picture where uncompensated spins located on a magnetically disordered surface shell are exchange coupled to the antiferromagnetic core. In all the studied NPs, the variation of the EB field as a function of temperature is described according to a negative exponential law with a similar decay constant, yielding a vanishing EB effect around T~40–50 K. In addition, the onset temperature for the EB effect in both NiO and Ni@NiO NPs seems to follow a universal dependence with the NiO crystallite size. - Highlights: • Comparison of the exchange bias effect in NiO and Ni(core)@NiO(shell) nanoparticles. • Universal temperature dependence of the exchange bias effect. • Suggested similar physical origin of the effect in both systems. • Size and crystallinity of the NiO shell hold the key for exchange bias properties.

  16. The Cu-CHA deNOx Catalyst in Action: Temperature-Dependent NH3-Assisted Selective Catalytic Reduction Monitored by Operando XAS and XES.

    Science.gov (United States)

    Lomachenko, Kirill A; Borfecchia, Elisa; Negri, Chiara; Berlier, Gloria; Lamberti, Carlo; Beato, Pablo; Falsig, Hanne; Bordiga, Silvia

    2016-09-21

    The small-pore Cu-CHA zeolite is today the object of intensive research efforts to rationalize its outstanding performance in the NH3-assisted selective catalytic reduction (SCR) of harmful nitrogen oxides and to unveil the SCR mechanism. Herein we exploit operando X-ray spectroscopies to monitor the Cu-CHA catalyst in action during NH3-SCR in the 150-400 °C range, targeting Cu oxidation state, mobility, and preferential N or O ligation as a function of reaction temperature. By combining operando XANES, EXAFS, and vtc-XES, we unambiguously identify two distinct regimes for the atomic-scale behavior of Cu active-sites. Low-temperature SCR, up to ∼200 °C, is characterized by balanced populations of Cu(I)/Cu(II) sites and dominated by mobile NH3-solvated Cu-species. From 250 °C upward, in correspondence to the steep increase in catalytic activity, the largely dominant Cu-species are framework-coordinated Cu(II) sites, likely representing the active sites for high-temperature SCR.

  17. Combined operando X-ray diffraction-electrochemical impedance spectroscopy detecting solid solution reactions of LiFePO4 in batteries.

    Science.gov (United States)

    Hess, Michael; Sasaki, Tsuyoshi; Villevieille, Claire; Novák, Petr

    2015-09-08

    Lithium-ion batteries are widely used for portable applications today; however, often suffer from limited recharge rates. One reason for such limitation can be a reduced active surface area during phase separation. Here we report a technique combining high-resolution operando synchrotron X-ray diffraction coupled with electrochemical impedance spectroscopy to directly track non-equilibrium intermediate phases in lithium-ion battery materials. LiFePO4, for example, is known to undergo phase separation when cycled under low-current-density conditions. However, operando X-ray diffraction under ultra-high-rate alternating current and direct current excitation reveal a continuous but current-dependent, solid solution reaction between LiFePO4 and FePO4 which is consistent with previous experiments and calculations. In addition, the formation of a preferred phase with a composition similar to the eutectoid composition, Li0.625FePO4, is evident. Even at a low rate of 0.1C, ∼20% of the X-ray diffractogram can be attributed to non-equilibrium phases, which changes our understanding of the intercalation dynamics in LiFePO4.

  18. In operando scanning electron microscopy and ultraviolet-visible spectroscopy studies of lithium/sulfur cells using all solid-state polymer electrolyte

    Science.gov (United States)

    Marceau, Hugues; Kim, Chi-Su; Paolella, Andrea; Ladouceur, Sébastien; Lagacé, Marin; Chaker, Mohamed; Vijh, Ashok; Guerfi, Abdelbast; Julien, Christian M.; Mauger, Alain; Armand, Michel; Hovington, Pierre; Zaghib, Karim

    2016-07-01

    Lithium/solid polymer electrolyte (SPE)/sulfur cells were studied in operando by two techniques: Scanning Electron Microscope (SEM) and ultraviolet-visible absorption spectroscopy (UV-vis). During the operation of the cell, extensive polysulfide dissolution in the solid polymer electrolyte (cross-linked polyethylene oxide) leads to the formation of a catholyte. A clear micrograph of the thick passivation layer on the sulfur-rich anode and the decreased SPE thickness by cycling confirmed the failure mechanism; the capacity decays by reducing the amount of active material, and by contributing to a charge inhibiting mechanism called polysulfide shuttle. The formation of elemental sulfur is clearly visible in real time during the charge process beyond 2.3 V. The non-destructive in operando UV-vis study also shows the presence of characteristic absorption peaks evolving with cycling, demonstrating the accumulation of various polysulfide species, and the predominant formation of S42- and of S62- during discharge and charge, respectively. This finding implies that the charge and discharge reactions are not completely reversible and proceed along different pathways.

  19. Combined operando X-ray diffraction-electrochemical impedance spectroscopy detecting solid solution reactions of LiFePO4 in batteries

    Science.gov (United States)

    Hess, Michael; Sasaki, Tsuyoshi; Villevieille, Claire; Novák, Petr

    2015-09-01

    Lithium-ion batteries are widely used for portable applications today; however, often suffer from limited recharge rates. One reason for such limitation can be a reduced active surface area during phase separation. Here we report a technique combining high-resolution operando synchrotron X-ray diffraction coupled with electrochemical impedance spectroscopy to directly track non-equilibrium intermediate phases in lithium-ion battery materials. LiFePO4, for example, is known to undergo phase separation when cycled under low-current-density conditions. However, operando X-ray diffraction under ultra-high-rate alternating current and direct current excitation reveal a continuous but current-dependent, solid solution reaction between LiFePO4 and FePO4 which is consistent with previous experiments and calculations. In addition, the formation of a preferred phase with a composition similar to the eutectoid composition, Li0.625FePO4, is evident. Even at a low rate of 0.1C, ~20% of the X-ray diffractogram can be attributed to non-equilibrium phases, which changes our understanding of the intercalation dynamics in LiFePO4.

  20. Combined operando X-ray diffraction–electrochemical impedance spectroscopy detecting solid solution reactions of LiFePO4 in batteries

    Science.gov (United States)

    Hess, Michael; Sasaki, Tsuyoshi; Villevieille, Claire; Novák, Petr

    2015-01-01

    Lithium-ion batteries are widely used for portable applications today; however, often suffer from limited recharge rates. One reason for such limitation can be a reduced active surface area during phase separation. Here we report a technique combining high-resolution operando synchrotron X-ray diffraction coupled with electrochemical impedance spectroscopy to directly track non-equilibrium intermediate phases in lithium-ion battery materials. LiFePO4, for example, is known to undergo phase separation when cycled under low-current-density conditions. However, operando X-ray diffraction under ultra-high-rate alternating current and direct current excitation reveal a continuous but current-dependent, solid solution reaction between LiFePO4 and FePO4 which is consistent with previous experiments and calculations. In addition, the formation of a preferred phase with a composition similar to the eutectoid composition, Li0.625FePO4, is evident. Even at a low rate of 0.1C, ∼20% of the X-ray diffractogram can be attributed to non-equilibrium phases, which changes our understanding of the intercalation dynamics in LiFePO4. PMID:26345306

  1. Oxygen Electrode Kinetics and Surface Composition of Dense (La0.75Sr0.25)0.95MnO3 on YSZ

    DEFF Research Database (Denmark)

    Wu, Yuehua; Hansen, Karin Vels; Norrman, Kion;

    2013-01-01

    Lanthanum strontium manganate (LSM) micro-electrodes with the nominal composition of (La0.75Sr0.25)0.95MnO3 were deposited on yttria stabilized zirconia (YSZ). The diameter varied from 20 – 100 m and the thickness was kept constant at ca. 0.5 m. Electrochemical characterization was carried out...... in situ at temperatures from 660 to 860 C using a controlled atmosphere high temperature scanning probe microscope (CAHT-SPM) setup for measurements of impedance spectroscopy and potential sweep. The oxygen partial pressure, pO2, was varied. Further, ex situ surface analysis by time of flight secondary...... kinetics are discussed in light of the surface compositions and compared with the literature on microelectrode and composite LSM-YSZ electrode kinetics....

  2. Deep oxidation of methane on particles derived from YSZ-supported Pd-Pt-(O) coatings synthesized by pulsed filtered cathodic arc

    Energy Technology Data Exchange (ETDEWEB)

    Horwat, D.; Endrino, J.L.; Boreave, A.; Karoum,R.; Pierson, J.F.; Weber, S.; Anders, A.; Vernoux, Ph.

    2008-12-12

    Methane conversion tests were performed on Pd, PdOy, Pd0.6Pt0.4Oy and Pd0.4Pt0.6Oy thin films deposited on yttria stabilized zirconia (YSZ) substrates. Pt containing films exhibited poor activity and high reducibility. As-deposited Pd and PdOy films showed good activity and transformed, during the cycling process, to particles dispersed on the YSZ substrates. The higher reaction rate of initially PdOy films was explained by a better dispersion of the catalyst. A drop of the reaction rate was observed when the temperature exceeded 735oC and 725oC for initially Pd and PdOy, respectively, which can be associated with the high-temperature reduction of PdO into Pd.

  3. Nano-hard template synthesis of pure mesoporous NiO and its application for streptavidin protein immobilization.

    Science.gov (United States)

    Wahab, Mohammad A; Darain, Farzana

    2014-04-25

    A simple and efficient immobilization of streptavidin protein (with hexa-histidine tag) onto the surface of mesoporous NiO is described. Before immobilization of streptavidin protein (with hexa-histidine tag) onto the surface of mesoporous NiO, we first synthesized well-organized mesoporous NiO by a nanocasting method using mesoporous silica SBA-15 as the hard template. Then, the well-organized mesoporous NiO particles were characterized by small angle x-ray diffraction (XRD), wide angle XRD, nitrogen adsorption/desorption, and transmission electron microscopy (TEM). TEM and small angle XRD suggested the formation of mesoporous NiO materials, whereas the wide angle XRD pattern of mesoporous NiO indicated that the nickel precursor had been transformed into crystalline NiO. The N2 sorption experiments demonstrated that the mesoporous NiO particles had a high surface area of 281 m2 g(-1), a pore volume of 0.51 cm3 g(-1) and a pore size of 4.8 nm. Next, the immobilization of streptavidin protein (with hexa-histidine tag) onto the surface of mesoporous NiO was studied. Detailed analysis using gel electrophoresis confirmed that this approach can efficiently bind his-tagged streptavidin onto the surface of mesoporous NiO material since the mesoporous NiO provides sufficient surface sites for the binding of streptavidin via non-covalent ligand binding with the histidine tag.

  4. 利用NIOS Ⅱ自定义指令实现高速DSP

    Institute of Scientific and Technical Information of China (English)

    高旭东; 陈金鹰; 叶舒亚

    2006-01-01

    Altera公司的Nios Ⅱ软核处理器以其低成本、设计灵活等特点,在嵌入式DSP应用领域得到广泛的应用。采用Nios Ⅱ处理器的定制指令,可以把用户自定义的功能直接添加到Nios Ⅱ CPU的算术逻辑单元中,加快专项任务的执行.方便地进行高速DSP。

  5. Magnetic dynamics of small alpha-Fe2O3 and NiO particles

    DEFF Research Database (Denmark)

    Lefmann, K.; Bødker, Franz; Hansen, Mikkel Fougt;

    1999-01-01

    We have studied the magnetic dynamics in nanocrystalline samples of alpha-Fe2O3 (hematite) and NiO by inelastic neutron scattering. By measuring around the structural and the antiferromagnetic reflections, we have probed uniform and staggered magnetic oscillations, respectively. In the hematite...... as a sign of superparamagnetic relaxation. Studies of the antiferromagnetic signal from NiO also show evidence of collective magnetic excitations, but with a higher energy of the precession state than for hematite. The inelastic signal at the structural reflection of NiO presents evidence for uniform...

  6. CdTeO3 Deposited Mesoporous NiO Photocathode for a Solar Cell

    OpenAIRE

    Chuan Zhao; Xiaoping Zou; Sheng He

    2014-01-01

    Semiconductor sensitized NiO photocathodes have been fabricated by successive ionic layer adsorption and reaction (SILAR) method depositing CdTeO3 quantum dots onto mesoscopic NiO films. A solar cell using CdTeO3 deposited NiO mesoporous photocathode has been fabricated. It yields a photovoltage of 103.7 mV and a short-circuit current density of 0.364 mA/cm2. The incident photon to current conversion efficiency (IPCE) value is found to be 12% for the newly designed NiO/CdTeO3 solar cell. It s...

  7. Electronic structures of N- and C-doped NiO from first-principles calculations

    OpenAIRE

    2010-01-01

    The large intrinsic band gap of NiO has hindered severely its potential application under visible-light irradiation. In this study, we have performed first-principles calculations on the electronic properties of N- and C-doped NiO to ascertain if its band gap may be narrowed theoretically. It was found that impurity bands driven by N 2p or C 2p states appear in the band gap of NiO and that some of these locate at the conduction band minimum, which leads to a significant band gap narrowing. Ou...

  8. Engineering NiO sensitive materials and its ultra-selective detection of benzaldehyde.

    Science.gov (United States)

    Yang, Fuchao; Guo, Zhiguang

    2016-04-01

    Ongoing interest in oxide semiconductor as components of gas sensing devices is motivated by environmental monitoring and intelligent control. NiO with different precursor solution were synthesized by aqueous chemical deposition and pyrolysis process. Here the method is quite facile, green and free of surfactant. Their morphology, crystal structure and chemical composition have been systemically characterized by various techniques. Interestingly, the microstructures of NiO can be engineered by different nickel salt (nitrate or chloride). These NiO based gas sensors showed substantially enhanced responses to benzaldehyde target analyte and exhibited fast response-recover feature. The observed gas sensing behavior is explained in terms of oxygen ionosorption mechanism.

  9. LED Display Controller Based on Nios II%Nios II的LED显示屏控制器设计

    Institute of Scientific and Technical Information of China (English)

    陈明义; 刘许亮

    2010-01-01

    基于μC/OS-II实时操作系统实现多任务管理运行模式,采用Nios II 32位处理器作为LED显示屏控制系统的核心,控制单屏幕多窗口任意显示.整个控制系统在一片FPGA上实现,使用SOPC Builder软件定制集成IP核,通过外扩存储设备实现数据的海量存储,解决了FPGA内部资源相对不足的问题.同时,合理组织数据存储方式,降低了数据处理和控制系统的复杂度.

  10. Effect of inlet fuel type on the degradation of Ni/YSZ anode of solid oxide fuel cell by carbon deposition

    Directory of Open Access Journals (Sweden)

    Suttichai Assabumrungrat

    2006-11-01

    Full Text Available According to the high operating temperature of Solid Oxide Fuel Cell (SOFC (700-1100ºC, it is known that some hydrocarbon fuels can be directly used as inlet fuel instead of hydrogen by feeding straight to the anode. This operation is called a direct internal reforming SOFC (DIR-SOFC. However, the major difficulty of this operation is the possible degradation of anode by the carbon deposition, as the carbon species are easily formed. In the present work, the effect of inlet fuel (i.e. H2, synthesis gas (H2+CO, CH4, CH4+H2O, CH3OH+H2O, and C2H5OH+H2O on the degradation of nickel cermet (Ni/YSZ, which is the most common anode material of SOFC, was studied.It was found from the work that hydrogen and synthesis gas (CO+H2 are proper to be used as direct inlet fuels for DIR-SOFC with Ni/YSZ anode, since the carbon formation on Ni/YSZ occurred in the small quantity. The mixture of methane and steam (CH4+H2O can also be used as the inlet feed, but the H2O/CH4 ratio plays an important role. In contrast, pure methane (CH4, methanol with steam (CH3OH+H2O and ethanol with steam (C2H5OH+H2O are not suitable for using as direct inlet fuel for DIR-SOFC with Ni/YSZ anode even the higher H2O/CH3OH and H2O/C2H5OH ratios were applied.

  11. The impact of steam and current density on carbon formation from biomass gasification tar on Ni/YSZ, and Ni/CGO solid oxide fuel cell anodes

    Science.gov (United States)

    Mermelstein, Joshua; Millan, Marcos; Brandon, Nigel

    The combination of solid oxide fuel cells (SOFCs) and biomass gasification has the potential to become an attractive technology for the production of clean renewable energy. However the impact of tars, formed during biomass gasification, on the performance and durability of SOFC anodes has not been well established experimentally. This paper reports an experimental study on the mitigation of carbon formation arising from the exposure of the commonly used Ni/YSZ (yttria stabilized zirconia) and Ni/CGO (gadolinium-doped ceria) SOFC anodes to biomass gasification tars. Carbon formation and cell degradation was reduced through means of steam reforming of the tar over the nickel anode, and partial oxidation of benzene model tar via the transport of oxygen ions to the anode while operating the fuel cell under load. Thermodynamic calculations suggest that a threshold current density of 365 mA cm -2 was required to suppress carbon formation in dry conditions, which was consistent with the results of experiments conducted in this study. The importance of both anode microstructure and composition towards carbon deposition was seen in the comparison of Ni/YSZ and Ni/CGO anodes exposed to the biomass gasification tar. Under steam concentrations greater than the thermodynamic threshold for carbon deposition, Ni/YSZ anodes still exhibited cell degradation, as shown by increased polarization resistances, and carbon formation was seen using SEM imaging. Ni/CGO anodes were found to be more resilient to carbon formation than Ni/YSZ anodes, and displayed increased performance after each subsequent exposure to tar, likely due to continued reforming of condensed tar on the anode.

  12. Development of Fe-Ni/YSZ-GDC electro-catalysts for application as SOFC anodes. XRD and TPR characterization, and evaluation in ethanol steam reforming reaction

    Energy Technology Data Exchange (ETDEWEB)

    Paz Fiuza, Raigenis da; Silva, Marcos Aurelio da; Boaventura, Jaime Soares [UFBA, Salvador, Bahia (Brazil). Energy and Materials Science Group

    2010-07-01

    Electro-catalysts based on Fe-Ni alloys were prepared using physical mixture and modified Pechini methods; they were supported on a composite of Yttria Stabilized Zirconia (YSZ) and Gadolinia Doped Ceria (GDC). The composites had compositions of 35% metal load and 65% support (70% wt. YSZ and 30% wt. GDC mixture) (cermets). The samples were characterized by Temperature-Programmed Reduction (TPR) and X-Ray Diffraction (XRD) and evaluated in ethanol steam reforming at 650 C for six hours and in the temperature range 300 - 900 C. The XRD results showed that the bimetallic sample calcined at 800 C formed a mixed oxide (NiFe{sub 2}O{sub 4}) in spinel structure; after reducing the sample in hydrogen, Ni-Fe alloys were formed. The presence of Ni decreased the final reduction temperature of the NiFe{sub 2}O{sub 4} species. The addition of Fe to Ni anchored to YSZ-GDC increased the hydrogen production and inhibits the carbon deposition. The bimetallic 30Fe5Ni samples reached an ethanol conversion of about 95%, and a hydrogen yield up to 48% at 750 C. In general, the ethanol conversion and hydrogen production were independent of the metal content in the electro-catalyst. However, the substitution of Ni for Fe significantly reduced the carbon deposition on the electro-catalyst: 74, 31 and 9 wt. % in the 35Ni, 20Fe15Ni, and 30Fe5Ni samples, respectively. (orig.)

  13. Preparation of electrolyte thin film on NiO-YSZ porous substrate for solid oxide fuel cells by electrophoretic deposition (I)

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S.W.; Lee, B.H.; Son, Y.B.; Song, H.S. [Korea Institute of Science and Technology, Seoul (Korea)

    1999-05-01

    Yttria-stabilized zirconia(YSZ) thin films for an anode support type solid oxide fuel cell(SOFC) was prepared by electrophoretic deposition(EPD). Kinetic model and properties of electrolyte film obtained by EPD on porous NiO-YSZ substrate were investigated. In the constant current mode, the deposited weight increased with time and the curve was well-fitted by Dihyperbola type function. In constant voltage mode, the deposited weight saturated with time, and the curve was fitted by the modified Zhangs' equation. There was little difference in the weight and microstructure of films between constant current and constant voltage conditions in short time(under 30 s), but the surface of deposited film at constant current condition was more smooth than that at constant voltage condition. Although zirconia films, obtained under either conditions at low electric field for long time processing, contained defects such as sagging and crack, sagging of film at constant voltage condition was more sever than for constant current condition. YSZ thin film with uniform thickness of less than 10 {mu}m by EPD was formed at constant current, 0.035 mA/cm{sup 2} for 10 s. 19 refs., 12 figs.

  14. Fabrication and performance of La0.8Sr0.2MnO3/YSZ graded composite cathodes for SOFC

    Institute of Scientific and Technical Information of China (English)

    SUN Kening; PIAO Jinhua; ZHANG Naiqing; CHEN Xinbing; XU Shen; ZHOU Derui

    2008-01-01

    The performance of multi-layer (1-x)La0.8Sr0.2MnO3/xYSZ graded composite cathodes was studied as electrode materials for intermediate solid oxide fuel cells (SOFC). The thermal expansion coefficient, electrical conductivity, and electrochemical performance of multi-layer composite cathodes were investigated. The thermal expansion coefficient and electrical conductivity decreased with the increase in YSZ content. The (1-x)La0.8Sr0.2MnO3/xYSZ composite cathode greatly increased the length of the active triple phase boundary line (TPBL) among electrode, electrolyte, and gas phase, leading to a decrease in polarization resistance and an increase in polarization current density. The polarization current density of the triple-layer graded composite cathode (0.77 A/cm2) was the highest and that of the monolayer cathode (0.13 A/cm2) was the lowest. The polarization resistance (Rp) of the triple-layer graded composite cathode was only 0.182Ω·cm2 and that of the monolayer composite cathode was 0.323Ω·cm2. The power density of the triple-layer graded composite cathode was the highest and that of the monolayer composite cathode was the lowest. The triple-layer graded composite cathode had superior performance.

  15. Structural characterisation of BaTiO{sub 3} thin films deposited on SrRuO{sub 3}/YSZ buffered silicon substrates and silicon microcantilevers

    Energy Technology Data Exchange (ETDEWEB)

    Colder, H.; Jorel, C., E-mail: corentin.jorel@unicaen.fr; Méchin, L. [GREYC, UMR 6072, CNRS, ENSICAEN, UCBN, 6 bd du Maréchal Juin, 14050 Caen Cedex (France); Domengès, B. [LAMIPS, CRISMAT-NXP Semiconductors-Presto Engineering laboratory, CNRS-UMR 6508, ENSICAEN, UCBN, 2 rue de la Girafe, 14 000 Caen (France); Marie, P.; Boisserie, M. [CIMAP, UMR 6252, CNRS, ENSICAEN, UCBN, CEA, 6 bd du Maréchal Juin, 14050 Caen Cedex (France); Guillon, S.; Nicu, L. [LAAS, CNRS, Univ de Toulouse, 7 avenue du Colonel Roche, 31400 Toulouse (France); Galdi, A. [GREYC, UMR 6072, CNRS, ENSICAEN, UCBN, 6 bd du Maréchal Juin, 14050 Caen Cedex (France); Department of Industrial Engineering, CNR-SPIN Salerno, Università di Salerno, 84084 Fisciano, Salerno (Italy)

    2014-02-07

    We report on the progress towards an all epitaxial oxide layer technology on silicon substrates for epitaxial piezoelectric microelectromechanical systems. (101)-oriented epitaxial tetragonal BaTiO{sub 3} (BTO) thin films were deposited at two different oxygen pressures, 5.10{sup −2} mbar and 5.10{sup −3} mbar, on SrRuO{sub 3}/Yttria-stabilized zirconia (YSZ) buffered silicon substrates by pulsed laser deposition. The YSZ layer full (001) orientation allowed the further growth of a fully (110)-oriented conductive SrRuO{sub 3} electrode as shown by X-ray diffraction. The tetragonal structure of the BTO films, which is a prerequisite for the piezoelectric effect, was identified by Raman spectroscopy. In the BTO film deposited at 5.10{sup −2} mbar strain was mostly localized inside the BTO grains whereas at 5.10{sup −3} mbar, it was localized at the grain boundaries. The BTO/SRO/YSZ layers were finally deposited on Si microcantilevers at an O{sub 2} pressure of 5.10{sup −3} mbar. The strain level was low enough to evaluate the BTO Young modulus. Transmission electron microscopy (TEM) was used to investigate the epitaxial quality of the layers and their epitaxial relationship on plain silicon wafers as well as on released microcantilevers, thanks to Focused-Ion-Beam TEM lamella preparation.

  16. Model-supported interpretation of the electrochemical characteristics of solid oxide fuel cells with Ni/YSZ cermet anodes; Modellgestuetzte Interpretation der elektrochemischen Charakteristik von Festoxid-Brennstoffzellen mit Ni/YSZ-Cermetanoden

    Energy Technology Data Exchange (ETDEWEB)

    Gewies, Stefan

    2009-01-29

    This work presents the development, validation and application of a multiscale model for the detailed description of a solid oxide fuel cell (SOFC) with a Ni/YSZ (nickel/yttria-stabilized zirconia) cermet anode. The aim of the study is the identification of the physico-chemical loss processes, as seen in impedance spectra and polarization curves. The model consists of an elementary kinetic description of the electrochemistry including the development of an electrical double layer at the electrode/electrolyte interface of the cermet anode, a homogenized description of charge and gas-phase transport in the electrodes as well as a macroscopic description of convective and diffusive mass transport in the gas phase above the electrodes. For the rst time this study allows for a complete description of the impedance spectra of a diffusively fuel-supplied cermet anode. By comparing simulations with experiments on symmetrical cells (University of Karlsruhe) three dominant loss processes could be identified. The model was extended to account for the description of segmented SOFCs. In correspondence with experimental data (German Aerospace Center) the simulations show strong gradients in current densities and gas concentrations. (orig.)

  17. A PRESERVAÇÃO DO PATRIMÔNIO EM MINAS GERAIS: A “LEI ROBIN HOOD” E OS CONSELHOS MUNICIPAIS DE PATRIMÔNIO

    OpenAIRE

    Luciana Christina Cruz e Souza; Moraes,Nilson Alves de

    2014-01-01

    O Estado de Minas Gerais possui uma história de presença pública na produção e na defesa do patrimônio cultural. Fundamentado na Lei Estadual 12.040 de 1995, o Instituto Estadual do Patrimônio Histórico e Artístico de Minas Gerais (IEPHA/MG), através de suas Resoluções e Deliberações, passou a condicionar os municípios em políticas de preservação do patrimônio constituindo modelos de ação suscetíveis à contrapartida do Imposto sobre Operações relativas a Circulação de Mercadorias e sobre Pres...

  18. Preparation and Characterization of NiO Nanoparticles by Anodic Arc Plasma Method

    Directory of Open Access Journals (Sweden)

    Hongxia Qiao

    2009-01-01

    Full Text Available NiO nanoparticles with average particle size of 25 nm were successfully prepared by anodic arc plasma method. The composition, morphology, crystal microstructure, specific surface area, infrared spectra, and particle size distribution of product were analyzed by using X-ray diffraction (XRD, transmission electron microscopy (TEM and the corresponding selected area electron diffraction (SAED, Fourier transform infrared (FTIR spectrum, and Brunauer-Emmett-Teller (BET N2 adsorption. The experiment results show that the NiO nanoparticles are bcc structure with spherical shape and well dispersed, the particle size distribution ranging from 15 to 45 nm with the average particle size is about 25 nm, and the specific surface area is 33 m2/g. The infrared absorption band of NiO nanoparticles shows blue shifts compared with that of bulk NiO.

  19. Ferromagnetic Behaviors in Fe-Doped NiO Nanofibers Synthesized by Electrospinning Method

    Directory of Open Access Journals (Sweden)

    Yi-Dong Luo

    2013-01-01

    Full Text Available Ni1−xFexO nanofibers with different Fe doping concentration have been synthesized by electrospinning method. An analysis of the phase composition and microstructure shows that Fe doping has no influence on the crystal structure and morphology of NiO nanofibers, which reveals that the doped Fe ions have been incorporated into the NiO host lattice. Pure NiO without Fe doping is antiferromagnetic, yet all the Fe-doped NiO nanofiber samples show obvious room-temperature ferromagnetic properties. The saturation magnetization of the nanofibers can be enhanced with increasing Fe doping concentration, which can be ascribed to the double exchange mechanism through the doped Fe ions and free charge carriers. In addition, it was found that the diameter of nanofibers has significant impact on the ferromagnetic properties, which was discussed in detail.

  20. p-Type Transparent NiO Thin Films By e-Beam Evaporation Techniques

    Directory of Open Access Journals (Sweden)

    K.J. Patel1,

    2011-01-01

    Full Text Available Nickel oxide (NiO semiconductors thin films were prepared by e-beam evaporation technique at different substrate temperatures ranging from room temperature to 400 °C on glass substrate. Glancing incident X-ray diffraction depict that with the increases in substrate temperature the preferred orientation changes from (111 to (200 direction. Atomic force microscopy was used to investigate the surface morphology of the NiO thin films. The transmittance of NiO thin film increases with substrate temperature. NiO thin film was also deposited on n-type indium tin oxide (ITO thin films to investigate the diode characteristic of p-NiO/n-ITO junction.

  1. A low cost matching motion estimation sensor based on the NIOS II microprocessor

    National Research Council Canada - National Science Library

    González, Diego; Botella, Guillermo; Meyer-Baese, Uwe; García, Carlos; Sanz, Concepción; Prieto-Matías, Manuel; Tirado, Francisco

    2012-01-01

    ...) and NIOS II microprocessor applying a C to Hardware (C2H) acceleration paradigm. The design, which involves several matching algorithms, is mapped using Very Large Scale Integration (VLSI) technology...

  2. A comprehensive comparison of dye-sensitized NiO photocathodes for solar energy conversion.

    Science.gov (United States)

    Wood, Christopher J; Summers, Gareth H; Clark, Charlotte A; Kaeffer, Nicolas; Braeutigam, Maximilian; Carbone, Lea Roberta; D'Amario, Luca; Fan, Ke; Farré, Yoann; Narbey, Stéphanie; Oswald, Frédéric; Stevens, Lee A; Parmenter, Christopher D J; Fay, Michael W; La Torre, Alessandro; Snape, Colin E; Dietzek, Benjamin; Dini, Danilo; Hammarström, Leif; Pellegrin, Yann; Odobel, Fabrice; Sun, Licheng; Artero, Vincent; Gibson, Elizabeth A

    2016-04-28

    We investigated a range of different mesoporous NiO electrodes prepared by different research groups and private firms in Europe to determine the parameters which influence good quality photoelectrochemical devices. This benchmarking study aims to solve some of the discrepancies in the literature regarding the performance of p-DSCs due to differences in the quality of the device fabrication. The information obtained will lay the foundation for future photocatalytic systems based on sensitized NiO so that new dyes and catalysts can be tested with a standardized material. The textural and electrochemical properties of the semiconducting material are key to the performance of photocathodes. We found that both commercial and non-commercial NiO gave promising solar cell and water-splitting devices. The NiO samples which had the two highest solar cell efficiency (0.145% and 0.089%) also gave the best overall theoretical H2 conversion.

  3. The magnetic properties of antiferromagnetic nanoparticles: NiO and αFe2O3

    DEFF Research Database (Denmark)

    Bahl, Christian Robert Haffenden

    Nickel oxide (NiO) and hematite (a-Fe2O3), both antiferromagnets, have magnetic properties which at nanoscale differ from those of the bulk materials. With emphasis on NiO nanoparticles and comparisons with a-Fe2O3 nanoparticles these magnetic propertiesare studied by a range of experimental...... techniques: elastic and inelastic neutron scattering, Mössbauer spectroscopy, x-ray diffraction, transmission electron microscopy and vibrating sample magnetometry. Knowledge of the size and shape of thenanoparticles is an often neglected prerequisite for studies of their magnetic properties. The Ni......O nanoparticles are found to be plate shaped with the (111) planes as plate faces, a thickness of about 2.3 nm and a diameter of about 13 nm. The magneticstructure is similar to that of bulk NiO, with the spins confined in the (111) planes. Measurements of the spin dynamics reveal a value of the magnetic...

  4. Properties of LiCoO{sub 2}-coated NiO MCFC cathode

    Energy Technology Data Exchange (ETDEWEB)

    Kuk, S.T.; Kim, C.K.; Chun, H.S. [Korea Univ., Seoul (Korea, Republic of); Kwon, H.J. [Samsung Electronics Co. Ltd., Suwon (Korea, Republic of)

    1996-12-31

    PVA-assisted sol-gel method is useful in producing metal oxides with large surface area at low temperature. We fabricated LiCoO{sub 2}-coated NiO(LC-NiO) cathode by PVA-assisted sol-gel method and measured its properties, The electrical conductivity of LC-NiO cathode was measured to be more than 5 times as high as that of NiO and unit cell test showed improved performance. From the SEM images and Raman spectra. we confirmed that the structure of LC-NiO was different from that of NiO. For 250 hours of steady operation of unit cells. the mean voltage of the cells were 0.78V for NiO and 0.85V for LiCoO{sub 2}-Coated NiO at a current density of l50mA/cm{sup 2}.

  5. [Territory and health: Antônio Pimentel's study on the Central Plateau].

    Science.gov (United States)

    Vergara, Moema de Rezende

    2008-01-01

    The article presents a report by Antônio Pimentel, physician with the 1892 Central Plateau Exploratory Commission, and analyzes its closing section, entitled "Pathology," which addresses the relations between health and the settlement of the Brazilian territory.

  6. In-situ and operando characterization of batteries with energy-dispersive synchrotron x-ray diffraction

    Science.gov (United States)

    Paxton, William Arthur

    Batteries play a pivotal role in the low-carbon society that is required to thwart the effects of climate change. Alternative low-carbon energy sources, such as wind and solar, are often intermittent and unreliable. Batteries are able capture their energy and deliver it later when it is needed. The implementation of battery systems in grid-level and transportation sectors is essential for efficient use of alternative energy sources. Scientists and engineers need better tools to analyze and measure the performance characteristics of batteries. One of the main hindrances in the progress of battery research is that the constituent electrode materials are inaccessible once an electrochemical cell is constructed. This leaves the researcher with a limited number of available feedback mechanisms to assess the cell's performance, e.g., current, voltage, and impedance. These data are limited in their ability to reveal the more-localized smaller-scale structural mechanisms on which the batteries' performance is so dependent. Energy-dispersive x-ray diffraction (EDXRD) is one of the few techniques that can internally probe a sealed battery. By analyzing the structural behavior of battery electrodes, one is able to gain insight to the physical properties on which the battery's performance is dependent. In this dissertation, EDXRD with ultrahigh energy synchrotron radiation is used to probe the electrodes of manufactured primary and secondary lithium batteries under in-situ and operando conditions. The technique is then applied to solve specific challenges facing lithium ion batteries. Diffraction spectra are collected from within a battery at 40 micrometer resolution. Peak-fitting is used to quantitatively estimate the abundance of lithiated and non-lithiated phases. Through mapping the distribution of phases within, structural changes are linked to the battery's galvanic response. A three-dimensional spatial analysis of lithium iron phosphate batteries suggests that evolution

  7. Preparation and Characterization of CeO2/YSZ/CeO2 Buffer Layers for YBCO Coated Conductors

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    CeO2 seed layer was deposited on rolling-assisted biaxially textured metal substrates by direct-current (DC) magnetron reactive sputtering. The effect of deposition temperature on epitaxial orientation of CeO2 thin films was examined. High quality CeO2 layers were achieved at deposition temperature from 750℃ to 850℃.Subsequently yttria-stabilized zirconia (YSZ) and CeO2 films were deposited to complete the buffer layer structure via the same process. The best samples exhibited a highly biaxial texture, as indicated by FWHM (full width half maximum) values in the range of 4°-5°, and 2°-4° for in-plane and out-of-plane orientations,respectively. Secondary ion mass spectrometer analysis confirmed the effective prevention of buffer layer against Ni and W metal interdiffusion. Atomic force microscope observations revealed a smooth, dense and crack-free surface morphology, which provided themselves as the good buffer structure to the YBa2Cu3O7-δ(YBCO) coated conductors.

  8. Modelling of CH4 multiple-reforming within the Ni-YSZ anode of a solid oxide fuel cell

    Science.gov (United States)

    Tran, Dang Long; Tran, Quang Tuyen; Sakamoto, Mio; Sasaki, Kazunari; Shiratori, Yusuke

    2017-08-01

    A new approach for the modelling of the simultaneous dry and steam reforming of CH4 (methane multiple-reforming (MMR)) within the Ni-YSZ anode of a solid oxide fuel cell (SOFC) is introduced in this paper. MMR is modelled by using artificial neural network (ANN) and fuzzy inference system (FIS) that can express the gas composition and temperature dependences of the consumption or the production rate of gaseous species involved in MMR. The necessary parameters for this approach are determined from the measured reforming kinetics for an anode-supported cell (ASC) fuelled by a CH4-CO2-H2O-N2 mixture. The developed MMR model is incorporated into a 3D-CFD planar ASC model to calculate the SOFC performance, and the calculated results match well with experimental values for the feed of simulated biogas (CH4/CO2 = 1) and H2. The established SOFC model considering MMR is a powerful tool to simulate the performance of internal reforming SOFC.

  9. First-principles assessment of hole transport in pure and Li-doped NiO.

    Science.gov (United States)

    Alidoust, Nima; Carter, Emily A

    2015-07-21

    Alloying nickel oxide (NiO) with lithium oxide (Li2O) at high Li concentrations may reduce NiO's band gap and expand its use as a light absorber in photocatalytic and tandem dye-sensitized solar cell technologies. In this work, we evaluate the viability of this alloy as a p-type hole transport material. We use embedded cluster models, along with unrestricted Hartree-Fock and complete active space self-consistent field theories, to study the impact of alloying on polaronic transport of holes. Our calculated energy barrier for hole transfer in undoped NiO is in excellent agreement with the experimental value of ∼0.1 eV. We predict that hole transport in NiO is anisotropic and mostly confined parallel to the (111) ferromagnetic planes. Applying the same model to Li-doped NiO indicates that isolated Li ions do not introduce free holes into NiO samples. However, free holes can be created in the homogeneous Li0.125Ni0.875O alloy, in which the Li concentration is very high. Our kinetic Monte Carlo calculations show that hole mobility in this alloy is lower than in undoped NiO. However, the additional free holes and the predicted lower band gap of Li0.125Ni0.875O should increase hole conductivity compared to NiO upon alloy formation. Therefore, Li0.125Ni0.875O alloys have potential for use as a hole transporter, as well as a sunlight absorber, in a variety of solar energy applications.

  10. 基于Nios Ⅱ的ARINC 429接口模块设计

    Institute of Scientific and Technical Information of China (English)

    王震; 尚明珠; 薛亚峰

    2016-01-01

    简要介绍Nios Ⅱ及ARINC 429的数据格式,详细阐述基于Nios Ⅱ完成ARINC 429模块的设计流程。最终在Quartus 9.0做仿真并通过,ARINC 429接口模块的设计可以缩短研发周期,降低工作强度。

  11. Oxygen bridges between NiO nanosheets and graphene for improvement of lithium storage.

    Science.gov (United States)

    Zhou, Guangmin; Wang, Da-Wei; Yin, Li-Chang; Li, Na; Li, Feng; Cheng, Hui-Ming

    2012-04-24

    Graphene has been widely used to dramatically improve the capacity, rate capability, and cycling performance of nearly any electrode material for batteries. However, the binding between graphene and these electrode materials has not been clearly elucidated. Here we report oxygen bridges between graphene with oxygen functional groups and NiO from analysis by X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and Raman spectroscopy and confirm the conformation of oxygen bridges by the first-principles calculations. We found that NiO nanosheets (NiO NSs) are bonded strongly to graphene through oxygen bridges. The oxygen bridges mainly originate from the pinning of hydroxyl/epoxy groups from graphene on the Ni atoms of NiO NSs. The calculated adsorption energies (1.37 and 1.84 eV for graphene with hydroxyl and epoxy) of a Ni adatom on oxygenated graphene by binding with oxygen are comparable with that on graphene (1.26 eV). However, the calculated diffusion barriers of the Ni adatom on the oxygenated graphene surface (2.23 and 1.69 eV for graphene with hydroxyl and epoxy) are much larger than that on the graphene (0.19 eV). Therefore, the NiO NS is anchored strongly on the graphene through a C-O-Ni bridge, which allows a high reversible capacity and excellent rate performance. The easy binding/difficult dissociating characteristic of Ni adatoms on the oxygenated graphene facilitates fast electron hopping from graphene to NiO and thus the reversible lithiation and delithiation of NiO. We believe that the understanding of this oxygen bridge between graphene and NiO will lead to the development of other high-performance electrode materials.

  12. Reactivity of NiO for 2,4-D degradation with ozone: XPS studies.

    Science.gov (United States)

    Rodríguez, Julia L; Valenzuela, Miguel A; Poznyak, Tatiana; Lartundo, Luis; Chairez, Isaac

    2013-11-15

    2,4-Dichlorophenoxyacetic acid (2,4-D) is usually used as a refractory model compound that requires a prolonged reaction time for mineralization. In this study, we found that nickel oxide (NiO) significantly improved 2,4-D degradation and mineralization in reaction with ozone. Other metal oxides, such as titania, silica and alumina, were also tested in this reaction, so that, the mineralization degree was almost the same for all of them (ca. 25%), whereas NiO showed more than 60% in 1h. These outstanding results led us to study in more depth the role of NiO as catalyst in the degradation of 2,4-D. For instance, the optimum NiO loading amount was 0.3 g L(-1). The catalytic ozonation showed a high stability after three reaction cycles. With the aim of identifying the surface species responsible for the high activity of NiO, besides knowing the byproducts during the degradation of 2,4-D, XPS and HPLC were mainly used as analytical tools. According to the results, the mineralization of 2,4-D was directly influenced by the adsorbed chlorate organic compounds and oxalate group onto NiO. Therefore, NiO plays a true role as a catalyst forming surface compounds which are subsequently decomposed causing an increase in the mineralization efficiency. In addition, it was possible to identify several degradation byproducts (2,4-diclorophenol, glycolic, fumaric, maleic and oxalic acids) that were included in a rational reaction pathway. It was proposed that 2,4-D elimination in presence of NiO as catalyst is a combination of processes such as: conventional ozonation, indirect mechanism (OH) and surface complex formation.

  13. 基于Nios II的CCD图像测温系统的设计

    Institute of Scientific and Technical Information of China (English)

    黄坤海; 张义德

    2007-01-01

    本文介绍了基于Nios II的CCD图像测温系统的实现方法.具体介绍了系统的硬件及软件设计,包括用ADV7180对CCD图像进行A/D转换,SOPC的自定义用户逻辑的设计,基于Nios II IDE的系统软件程序的设计等.

  14. 基于Nios II的ARINC 429接口模块设计

    Institute of Scientific and Technical Information of China (English)

    王震; 尚明珠; 薛亚峰

    2016-01-01

    简要介绍Nios II及ARINC 429的数据格式,详细阐述基于Nios II完成ARINC 429模块的设计流程。最终在Quartus 9.0做仿真并通过,ARINC 429接口模块的设计可以缩短研发周期,降低工作强度。

  15. 基于Nios Ⅱ的PWM控制电路设计%The PWM Controller Design Based on Nios

    Institute of Scientific and Technical Information of China (English)

    余毅; 马骋; 贾惠波

    2008-01-01

    本文详细论述了基于Altera Nios Ⅱ软核处理器的PWM控制电路的设计方法,介绍了系统设计的各个步骤.该电路在一块基于Altera Cyclone Ⅱ FPGA的SOPC Board评估板上实现,完全满足设计要求.本文对基于NIOS II进行系统设计具有实际参考价值.

  16. Enhanced magnetic properties of NiO powders by the mechanical activation of aluminothermic reduction of NiO prepared by a ball milling process

    Energy Technology Data Exchange (ETDEWEB)

    Padhan, Aneeta Manjari; Ravikumar, P. [Department of Physics, Indian Institute of Technology Guwahati, Guwahati 781039 (India); Saravanan, P. [Advanced Magnetic Lab, Defence Metallurgical Research Laboratory, Hyderabad 500058 (India); Alagarsamy, Perumal, E-mail: perumal@iitg.ernet.in [Department of Physics, Indian Institute of Technology Guwahati, Guwahati 781039 (India)

    2016-11-15

    We report the effect of mechanical activation on NiO–Al (x wt%) reduction reaction and resulting structural and magnetic properties by carrying out high-energy planetary ball milling. The pure NiO (un-milled) and milled NiO–Al (x≤2.5) powders exhibit face centered cubic structure, but the antiferromagnetic nature of pure NiO powder shows significant room temperature ferromagnetism with moderate moment and coercivity after milling due to non-stoichiometry in NiO caused by the defects, size reduction and oxidation of Ni. On the other hand, the addition of Al between 2.5 and 10% in NiO forms solid solution of NiO–Al with considerable reduction in the moment due to the atomic disorder. With increasing Al above 10%, NiO reduction reaction progresses gradually and as a result, the average magnetization increases from 0.57 to 4.3 emu/g with increasing Al up to 25%. A maximum of 91% reduction was observed for NiO–Al (40%) powders in 30 h of milling with a large increase in magnetization (~24 emu/g) along with the development of α-Al{sub 2}O{sub 3}. Thermomagnetization data reveal the presence of mixed magnetic phases in milled NiO powders and the component of induced ferromagnetic phase fades out with increasing Al due to the formation of Ni from the NiO–Al reduction reaction. The changes in the structural and magnetic properties are discussed on the basis of mechanical activation on the reduction of NiO by Al. The controlled reduction reaction with different Al content in NiO–Al is encouraging for the applications in catalysis and process of ore reduction. - Highlights: • Preparation of Ni/Al{sub 2}O{sub 3} nanocomposite by mechanical activation of NiO–Al reduction. • Study the effect of Al addition on the reduction reaction of NiO–Al powders. • Understand the change in the structural and microstructural properties of NiO–Al. • Investigate role of reduction of NiO by Al on resulting magnetic property of NiO–Al. • Study the magnetic phase

  17. Ultrafast synthesis of yolk-shell and cubic NiO Nanopowders and application in lithium ion batteries.

    Science.gov (United States)

    Choi, Seung Ho; Kang, Yun Chan

    2014-02-26

    A continuous one-pot method was employed to synthesize yolk-shell and single-crystalline cubic NiO powders in a few seconds. Submicrometer-sized NiO yolk-shell particles were prepared by spray pyrolysis at 900 °C. Single-crystalline cubic NiO nanopowders were prepared by one-pot flame spray pyrolysis from NiO vapors. Particle surface areas of the yolk-shell and single-crystalline cubic NiO powders as obtained using the Brunauer-Emmett-Teller method were 8 and 5 m(2) g(-1), respectively. The mean crystallite sizes of the yolk-shell-structured and cubic NiO powders were 50 and 80 nm, respectively. The yolk-shell and single-crystalline cubic NiO powders delivered discharge capacities of 951 and 416 mA h g(-1), respectively, after 150 cycles, and the corresponding capacity retentions measured after the first cycle were 106 and 66%, respectively. The yolk-shell-structured NiO powders showed rate performance better than that of the single-crystalline cubic NiO nanopowders. Even at a high current density of 1 A g(-1), the discharge capacity of the yolk-shell-structured NiO powders was as high as 824 mA h g(-1) after 50 cycles, in which the current densities were increased stepwise.

  18. The observation of chemiluminescent NiO* emissions in the laboratory and in the night airglow

    Directory of Open Access Journals (Sweden)

    W. F. J. Evans

    2011-09-01

    Full Text Available The recent finding of an orange spectral feature in OSIRIS/Odin spectra of the night airglow near 87 km has raised interest in the origin of the emission. The feature was positively identified as the chemiluminescent FeO* emission where the iron is of meteoric origin. Since the meteorite source of atomic metals in the mesosphere contains both iron and nickel, with Ni being typically 6 % of Fe, it is expected that faint emissions involving Ni should also be present in the night airglow. The present study summarizes the laboratory observations of chemiluminescent NiO* emissions and includes a search for the NiO* signature in the night airglow. A very faint previously unidentified "continuum" extending longwave of 440 nm has been detected in the night airglow spectra obtained with two space-borne limb viewing instruments. Through a comparison with laboratory spectra this continuum is identified as arising from the NiO* emission. The altitude profile of the new airglow emission has also been measured. The similarity of the altitude profiles of the FeO* and NiO* emissions also suggests the emission is NiO as both can originate from reaction of the metal atoms with mesospheric ozone. The observed NiO* to FeO* ratio exhibits considerable variability; possible causes of this observed variation are briefly discussed.

  19. Preparation of NiO nanoflakes under different calcination temperatures and their supercapacitive and optical properties

    Science.gov (United States)

    Zhao, Jiangshan; Liu, Hua; Zhang, Qiang

    2017-01-01

    The NiO nanocrystals were successfully prepared by calcinating Ni(OH)2 precursor synthesized via a facile ion diffusion controlled by ion exchange membrane without adding any solvent or template. X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) isotherm, X-ray photoelectron spectroscopy (XPS) and Ultraviolet-visible (UV-vis) analysis were used to investigate the crystallinity, morphology, surface and porosity characteristics, chemical composition and optical properties in more detail. The pseudocapacitive behavior of the NiO samples was investigated by cyclic voltammograms (CV) and galvanostatic charge-discharge tests in 2 M KOH. The results analysis reveals that both specific capacitance and surface area decrease with the increase of calcination temperatures. Among the NiO samples, the NiO-400 nanoflakes calcinated at 400 °C possess the highest specific capacitance of 381 F g-1 at a current density of 2 A g-1, but much lower than the Ni(OH)2 sample. In addition, the UV-vis analysis shows that there is a red shift of absorption peak for the three NiO samples with the increasing temperature and the NiO-400 has a broad band gap of 3.3 eV, which renders the material highly interesting for application in photocatalyst.

  20. Atomic layer deposition of NiO hole-transporting layers for polymer solar cells.

    Science.gov (United States)

    Hsu, Che-Chen; Su, Heng-Wei; Hou, Cheng-Hung; Shyue, Jing-Jong; Tsai, Feng-Yu

    2015-09-25

    NiO is an attractive hole-transporting material for polymer solar cells (PSCs) owing to its excellent stability and electrical/optical properties. This study demonstrates, for the first time, fabrication of uniform, defect-free, and conformal NiO ultra-thin films for use as hole-transporting layers (HTLs) in PSCs by atomic layer deposition (ALD) through optimization of the ALD processing parameters. The morphological, optical, and electrical properties of ALD NiO films were determined to be favorable for their HTL application. As a result, PSCs containing an ALD NiO HTL with an optimized thickness of 4 nm achieved a power conversion efficiency (PCE) of 3.4%, which was comparable to that of a control device with a poly(3,4-ethylenedioxy-thiophene):poly(styrene-sulfonate) HTL. The high quality and manufacturing scalability of ALD NiO films demonstrated here will facilitate the adoption of NiO HTLs in PSCs.

  1. A facile homogeneous precipitation synthesis of NiO nanosheets and their applications in water treatment

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Junfeng, E-mail: daidai02304@163.com [School of Chemistry and Materials Engineering, Changshu Institute of Technology, Changshu (China); Jiangsu Laboratory of Advanced Functional Materials, Changshu Institute of Technology, Changshu (China); Tan, Yang; Su, Kang; Zhao, Junjie; Yang, Chen; Sang, Lingling [School of Chemistry and Materials Engineering, Changshu Institute of Technology, Changshu (China); Lu, Hongbin [National Laboratory of Solid State Microstructures and College of Engineering and Applied Sciences, Nanjing University, Nanjing (China); Chen, JianHua [School of Chemistry and Materials Engineering, Changshu Institute of Technology, Changshu (China); Jiangsu Laboratory of Advanced Functional Materials, Changshu Institute of Technology, Changshu (China)

    2015-05-15

    Highlights: • NiO nanosheets were synthesized via a facile homogeneous precipitation method. • The NiO nanosheets have a large surface area. • This preparation method was low-cost, simple equipments, easy preparation, short reaction time and better repeatability. • The product also showed a favourable ability to remove Cr(VI) and Congo red (CR) in water treatment. - Abstract: NiO nanosheets were successfully synthesized by a facile homogeneous precipitation method with the assistance of ethanol amine. The sample was characterized by X-ray diffraction (XRD), scanning electronic microscopy (SEM), transmission electron microscopy (TEM), and nitrogen adsorption–desorption techniques. The results demonstrated that the as-prepared product was cubic NiO nanosheets with a large surface area of 170.1 m{sup 2} g{sup −1}. Further, the as-prepared product was used to investigate its potential application for wastewater treatment. The maximum adsorption capacity for Cr(VI) and Congo red (CR) on NiO nanosheets has been determined using the Langmuir equation and found to reach up to 48.98 and 167.73 mg g{sup −1}, respectively. It could be concluded that NiO nanosheets with special surface features had the potential as adsorbents for wastewater treatment.

  2. Potentiometric Zinc Ion Sensor Based on Honeycomb-Like NiO Nanostructures

    Directory of Open Access Journals (Sweden)

    Magnus Willander

    2012-11-01

    Full Text Available In this study honeycomb-like NiO nanostructures were grown on nickel foam by a simple hydrothermal growth method. The NiO nanostructures were characterized by field emission electron microscopy (FESEM, high resolution transmission electron microscopy (HRTEM and X-ray diffraction (XRD techniques. The characterized NiO nanostructures were uniform, dense and polycrystalline in the crystal phase. In addition to this, the NiO nanostructures were used in the development of a zinc ion sensor electrode by functionalization with the highly selective zinc ion ionophore 12-crown-4. The developed zinc ion sensor electrode has shown a good linear potentiometric response for a wide range of zinc ion concentrations, ranging from 0.001 mM to 100 mM, with sensitivity of 36 mV/decade. The detection limit of the present zinc ion sensor was found to be 0.0005 mM and it also displays a fast response time of less than 10 s. The proposed zinc ion sensor electrode has also shown good reproducibility, repeatability, storage stability and selectivity. The zinc ion sensor based on the functionalized NiO nanostructures was also used as indicator electrode in potentiometric titrations and it has demonstrated an acceptable stoichiometric relationship for the determination of zinc ion in unknown samples. The NiO nanostructures-based zinc ion sensor has potential for analysing zinc ion in various industrial, clinical and other real samples.

  3. Fabrication and characterization of NiO nanoparticles by precipitation from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Moghaddam, Javad; Hashemi, Elham [Sahand University of Technology, Tabriz (Iran, Islamic Republic of)

    2014-03-15

    Present work involves synthesis of NiO nanoparticles using chemical homogeneous precipitation (CHP) method as a facile procedure. Ammonia as a complex agent was used in this method. Effects of different types of complexation-precipitation methods on the crystallinity and morphology of nanoparticles were investigated. NiO particles were prepared by direct precipitation method from NiSO4 solution to compare crystallinity and morphology of NiO particles with particles obtained via complexation-precipitation methods. Our major intent was to investigate the effect of complex agent on the crystallization and growth of NiO nanoparticles. Results showed that the best condition for synthesizing spherical NiO shape was using NaOH as decomposing agent, of which the consequence was more uniformity and spherical nanoparticles with a diameter in the range of 40-60 nm. The size of the nickel oxide and nickel hydroxide nanoparticles was estimated by X-ray powder diffraction (XRD) pattern. The chemical structure information of the particles was studied by Fourier transform infrared (FT-IR) spectroscopy. Spherical, elliptical, sheet or flowerlike shapes were detected by field emission scanning electron microscopy (FESEM) analysis. Results showed that by the use of ammonia as complex agent, crystalline state and particles size distribution of NiO nanoparticles improved.

  4. Atomic layer deposition of NiO hole-transporting layers for polymer solar cells

    Science.gov (United States)

    Hsu, Che-Chen; Su, Heng-Wei; Hou, Cheng-Hung; Shyue, Jing-Jong; Tsai, Feng-Yu

    2015-09-01

    NiO is an attractive hole-transporting material for polymer solar cells (PSCs) owing to its excellent stability and electrical/optical properties. This study demonstrates, for the first time, fabrication of uniform, defect-free, and conformal NiO ultra-thin films for use as hole-transporting layers (HTLs) in PSCs by atomic layer deposition (ALD) through optimization of the ALD processing parameters. The morphological, optical, and electrical properties of ALD NiO films were determined to be favorable for their HTL application. As a result, PSCs containing an ALD NiO HTL with an optimized thickness of 4 nm achieved a power conversion efficiency (PCE) of 3.4%, which was comparable to that of a control device with a poly(3,4-ethylenedioxy-thiophene):poly(styrene-sulfonate) HTL. The high quality and manufacturing scalability of ALD NiO films demonstrated here will facilitate the adoption of NiO HTLs in PSCs.

  5. Transparent nanostructured electrodes: Electrospun NiO nanofibers/NiO films

    Energy Technology Data Exchange (ETDEWEB)

    Lamastra, F.R. [Italian Interuniversity Consortium on Materials Science and Technology (INSTM), Research Unit Roma Tor Vergata, Via del Politecnico 1, 00133 Rome (Italy); Nanni, F. [Italian Interuniversity Consortium on Materials Science and Technology (INSTM), Research Unit Roma Tor Vergata, Via del Politecnico 1, 00133 Rome (Italy); Department of Enterprise Engineering, University of Rome Tor Vergata, Via del Politecnico 1, 00133 Rome (Italy); Menchini, F. [ENEA, CR Casaccia, Via Anguillarese 301, 00123 Rome (Italy); Nunziante, P. [Italian Interuniversity Consortium on Materials Science and Technology (INSTM), Research Unit Roma Tor Vergata, Via del Politecnico 1, 00133 Rome (Italy); Department of Chemical Sciences and Technologies, University of Rome Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome (Italy); Grilli, M.L., E-mail: marialuisa.grilli@enea.it [ENEA, CR Casaccia, Via Anguillarese 301, 00123 Rome (Italy)

    2016-02-29

    Polyvinylpyrrolidone (PVP)/nickel(II) acetate precursor fibers were deposited by electrospinning directly on radio frequency sputtered thin Ni and NiO films grown on quartz substrate, starting from Ni(II) acetate and PVP solution in ethanol. The samples were calcined in air in the temperature range 400–500 °C to obtain transparent and conductive p-type NiO nanofibers on NiO films. A higher density of nanofibers was obtained on Ni/quartz substrates, as compared to NiO/quartz ones, demonstrating the feasibility of fiber adhesion directly to an insulating substrate previously coated by a thin Ni layer. Samples were characterized by field emission-scanning electron microscopy, X-ray diffraction, spectrophotometric and resistance measurements. - Highlights: • Nanostructured electrodes: electrospun NiO nanofibers/NiO films were fabricated. • NiO fibers were directly grown on insulating substrate coated by thin Ni or NiO films. • Good quality crystalline fibers were obtained at low calcination temperatures. • Transparent and conductive p-type electrodes were fabricated.

  6. Structural properties and optical characterization of flower-like Mg doped NiO

    Directory of Open Access Journals (Sweden)

    Ghazaleh Allaedini

    2015-07-01

    Full Text Available In this study, un-doped and Mg doped NiO nanoparticles have been synthesized through a simple sol-gel method. To investigate the effect of Mg-doping on the structure of NiO, the obtained nanoparticles were characterized using scanning electron microscopy (SEM. Flower/star like morphology was clearly observed in the SEM micrographs. The BET (Brunauer-Emmett-Teller nitrogen absorption isotherm exhibits high specific surface area (∼37 m2 /g for the Mg doped NiO nanoparticles. X-Ray diffraction (XRD of the prepared Mg-NiO nanoparticles showed a face-centered cubic (f.c.c structure, and the average particle size was estimated to be 32 nm using Scherrer’s formula. Energy Dispersive X-Ray (EDX confirms that the NiO particles are successfully doped with Mg. Photoluminescence (PL and UV-Vis optical absorption characteristics of the prepared nanoparticles have also been investigated in this study. The PL emission response showed a blue shift when NiO was doped with Mg, which is indicative of interstitial oxygen. The UV-Vis results demonstrate a band gap increase as NiO nanoparticles are doped with Mg.

  7. PATRIMÓNIO JUDAICO E TURISMO CULTURAL EM TRANCOSO

    Directory of Open Access Journals (Sweden)

    Bárbara Saraiva

    2013-06-01

    Full Text Available Da presença judaica em Portugal resta hoje um legado patrimonial muito relevante que se exprime através de testemunhos materiais e imateriais desta comunidade religiosa minoritária.As judiarias, as sinagogas e as marcas de simbologia religiosa judaica e cristã-nova constituem aspetos do património material judaico peninsular, como é visível em cidades como, por exemplo, Castelo de Vide, Estremoz, Guarda, Évora e Trancoso.O centro histórico de Trancoso é aquele que na região da Beira Interior, contém, até ao momento, o maior número de marcas mágico-religiosas distribuídas fundamentalmente na parte oriental do aglomerado urbano.A tomada de consciência do elevado valor patrimonial dos centros históricos, em particular de Trancoso, desencadeia a necessária recuperação física, funcional e social, a pensar no futuro, que passa necessariamente pelo turismo e, neste caso, pelo turismo cultural.

  8. Tempo e patrimônio Temporality and patrimony

    Directory of Open Access Journals (Sweden)

    François Hartog

    2006-12-01

    Full Text Available O artigo discute a redefinição da "memória" e do "patrimônio" dentro do novo "regime de historicidade" que o Ocidente vive após a Queda do Muro de Berlim (1989. Estas palavras-chave são tratadas como indícios, sintomas, de nossa relação com o tempo, como testemunhas da "crise" da ordem presente do tempo. O problema abordado: um novo regime de historicidade, centrado sobre o presente, estaria se formulando? Para o autor, ocorreu um crescimento rápido da categoria do presente e se impôs a evidência de um presente onipresente, que ele nomeia "presentismo", onde se vive entre a amnésia e a vontade de nada esquecer.This article discusses the redefinition of "memory" and "patrimony" within the new "regime of historicity" set in motion in the West after the fall of the Berlin Wall (1989. These keywords are treated as indicators or symptoms of our relation with time, as witnesses of the "crises" of the present order of time. The question that is approached is the following: is a new regime of historicity, one based on the present, taking shape? In the author's view, the category of present has grown rather fast and imposed an omnipotent present, which he names "presentism". This condition causes one to be torn between amnesia and the desire not to forget.

  9. 嵌入式处理器Nios Ⅱ与液晶显示模块的接口及应用%Interface Between the Embedded Processor Nios Ⅱ and the Liquid Crystal Display Module and its Application

    Institute of Scientific and Technical Information of China (English)

    包明; 余成波

    2006-01-01

    文中介绍了一种基于嵌入式Nios Ⅱ软核处理器的SOPC(System On Programmable Chip)的设计方法,给出了软核处理器Nios Ⅱ与液晶显示模块的接口和图形显示的编程技术,以及Bresenham画线算法的Nios Ⅱ应用程序.

  10. Estudo de validação da bateria de provas de raciocínio (BPR-5)

    OpenAIRE

    Ricardo Primi; Almeida,Leandro S.

    2000-01-01

    Esse estudo investiga a validade e precisão da BPR-5, versão reduzida da Bateria de Provas de Raciocínio Diferencial (BPRD) de Almeida (1988), composta por cinco subtestes: Raciocínio Abstrato, Raciocínio Verbal, Raciocínio Numérico, Raciocínio Espacial e Raciocínio Mecânico. A BPR-5 foi aplicada em 1243 alunos brasileiros (N=771) e portugueses (N=472) da sexta série do ensino fundamental até a terceira série do ensino médio. Os coeficientes de consistência interna variaram de 0,62 a 0,84 e o...

  11. Hard X-rays in–soft X-rays out: An operando piggyback view deep into a charging lithium ion battery with X-ray Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Braun, Artur, E-mail: artur.braun@alumni.ethz.ch [Laboratory for High Performance Ceramics. Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf (Switzerland); Nordlund, Dennis [Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94720 (United States); Song, Seung-Wan [Department of Fine Chemical Engineering & Applied Chemistry, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Huang, Tzu-Wen [Laboratory for High Performance Ceramics. Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf (Switzerland); Sokaras, Dimosthenis [Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94720 (United States); Liu, Xiasong; Yang, Wanli [Advanced Light Source, Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Weng, Tsu-Chien [Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94720 (United States); Liu, Zhi [Advanced Light Source, Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

    2015-04-15

    Graphical abstract: - Abstract: For lithium intercalation battery electrodes, understanding of the electronic structure of bulk and surface is essential for their operation and functionality. Soft X-rays are excellent probes for such electronic structure information, but soft X-rays are predominantly surface sensitive and thus cannot probe the bulk. Moreover, soft X-rays hardly permit meaningful in situ and operando studies in battery assemblies. We show here how we penetrate with hard X-rays (>10 keV) in situ a lithium cell, containing a manganite-based cathode. Through X-ray Raman spectroscopy we extract the Mn 2p multiplet from the entire cathode material, thus obtaining bulk-sensitive electronic structure information during battery charging and discharging.

  12. Length-Scale-Dependent Phase Transformation of LiFePO4 : An In situ and Operando Study Using Micro-Raman Spectroscopy and XRD.

    Science.gov (United States)

    Siddique, N A; Salehi, Amir; Wei, Zi; Liu, Dong; Sajjad, Syed D; Liu, Fuqiang

    2015-08-03

    The charge and discharge of lithium ion batteries are often accompanied by electrochemically driven phase-transformation processes. In this work, two in situ and operando methods, that is, micro-Raman spectroscopy and X-ray diffraction (XRD), have been combined to study the phase-transformation process in LiFePO4 at two distinct length scales, namely, particle-level scale (∼1 μm) and macroscopic scale (∼several cm). In situ Raman studies revealed a discrete mode of phase transformation at the particle level. Besides, the preferred electrochemical transport network, particularly the carbon content, was found to govern the sequence of phase transformation among particles. In contrast, at the macroscopic level, studies conducted at four different discharge rates showed a continuous but delayed phase transformation. These findings uncovered the intricate phase transformation in LiFePO4 and potentially offer valuable insights into optimizing the length-scale-dependent properties of battery materials.

  13. Selective Alcohol Oxidation by a Copper TEMPO Catalyst: Mechanistic Insights by Simultaneously Coupled Operando EPR/UV-Vis/ATR-IR Spectroscopy.

    Science.gov (United States)

    Rabeah, Jabor; Bentrup, Ursula; Stößer, Reinhard; Brückner, Angelika

    2015-09-28

    The first coupled operando EPR/UV-Vis/ATR-IR spectroscopy setup for mechanistic studies of gas-liquid phase reactions is presented and exemplarily applied to the well-known copper/TEMPO-catalyzed (TEMPO=(2,2,6,6-tetramethylpiperidin-1-yl)oxyl) oxidation of benzyl alcohol. In contrast to previous proposals, no direct redox reaction between TEMPO and Cu(I) /Cu(II) has been detected. Instead, the role of TEMPO is postulated to be the stabilization of a (bpy)(NMI)Cu(II) -O2 (⋅-) -TEMPO (bpy=2,2'-bipyridine, NMI=N-methylimidazole) intermediate formed by electron transfer from Cu(I) to molecular O2 .

  14. HERFD-XANES and XES as complementary operando tools for monitoring the structure of Cu-based zeolite catalysts during NOx-removal by ammonia SCR

    Science.gov (United States)

    Günter, T.; Doronkin, D. E.; Carvalho, H. W. P.; Casapu, M.; Grunwaldt, J.-D.

    2016-05-01

    In this article, we demonstrate the potential of hard X-ray techniques to characterize catalysts under working conditions. Operando high energy resolution fluorescence detected (HERFD) XANES and valence to core (vtc) X-ray emission spectroscopy (XES) have been used in a spatially-resolved manner to study Cu-zeolite catalysts during the standard-SCR reaction and related model conditions. The results show a gradient in Cu oxidation state and coordination along the catalyst bed as the reactants are consumed. Vtc-XES gives complementary information on the direct adsorption of ammonia at the Cu sites. The structural information on the catalyst shows the suitability of X-ray techniques to understand catalytic reactions and to facilitate catalyst optimization.

  15. Image Processing System of IRFPA Based on Nios Ⅱ%基于Nios Ⅱ的红外焦平面图像处理系统

    Institute of Scientific and Technical Information of China (English)

    董海; 朱斌; 陈代中; 郭立新; 乐静; 罗冠泰

    2011-01-01

    According to the flaws of complicated circuit and high cost in DSP+FPGA structure, an infrared image processing system implemented in Nios II embedded in FPGA is designed. The system includes Nios II processor, A/D conversion and infrared image processing, and achieves the functions of blind pixel compensation, multi-point temperature correction, median filtering and gray transformation. The result shows that the system is small in bulk, Iow in cost, short in exploitation cycle and with strong real-time performance.%针对数字信号处理(Digital Signal Processing,DSP)+现场可编程门阵列(Field Programmable Gate Array,FPGA)硬件架构存在硬件电路设计复杂、成本高等缺点,设计一套基于FPGA内嵌Nios Ⅱ软核的红外图像处理系统.系统包含Nios Ⅱ主控模块、A/D转换模块和红外图像预处理模块,实现了盲元补偿、两点多段校正、中值滤波和灰度变换等功能.验证结果表明,该系统具有体积小、成本低、开发周期短、实时性强等优点.

  16. Insights into the Activity and Deactivation of the Methanol-to-Olefins Process over Different Small-Pore Zeolites As Studied with Operando UV-vis Spectroscopy.

    Science.gov (United States)

    Goetze, Joris; Meirer, Florian; Yarulina, Irina; Gascon, Jorge; Kapteijn, Freek; Ruiz-Martínez, Javier; Weckhuysen, Bert M

    2017-06-02

    The nature and evolution of the hydrocarbon pool (HP) species during the Methanol-to-Olefins (MTO) process for three small-pore zeolite catalysts, with a different framework consisting of large cages interconnected by small eight-ring windows (CHA, DDR, and LEV) was studied at reaction temperatures between 350 and 450 °C using a combination of operando UV-vis spectroscopy and online gas chromatography. It was found that small differences in cage size, shape, and pore structure of the zeolite frameworks result in the generation of different hydrocarbon pool species. More specifically, it was found that the large cage of CHA results in the formation of a wide variety of hydrocarbon pool species, mostly alkylated benzenes and naphthalenes. In the DDR cage, 1-methylnaphthalene is preferentially formed, while the small LEV cage generally contains fewer hydrocarbon pool species. The nature and evolution of these hydrocarbon pool species was linked with the stage of the reaction using a multivariate analysis of the operando UV-vis spectra. In the 3-D pore network of CHA, the reaction temperature has only a minor effect on the performance of the MTO catalyst. However, for the 2-D pore networks of DDR and LEV, an increase in the applied reaction temperature resulted in a dramatic increase in catalytic activity. For all zeolites in this study, the role of the hydrocarbon species changes with reaction temperature. This effect is most clear in DDR, in which diamantane and 1-methylnaphthalene are deactivating species at a reaction temperature of 350 °C, whereas at higher temperatures diamantane formation is not observed and 1-methylnaphthalene is an active species. This results in a different amount and nature of coke species in the deactivated catalyst, depending on zeolite framework and reaction temperature.

  17. Insights into the Activity and Deactivation of the Methanol-to-Olefins Process over Different Small-Pore Zeolites As Studied with Operando UV–vis Spectroscopy

    Science.gov (United States)

    2017-01-01

    The nature and evolution of the hydrocarbon pool (HP) species during the Methanol-to-Olefins (MTO) process for three small-pore zeolite catalysts, with a different framework consisting of large cages interconnected by small eight-ring windows (CHA, DDR, and LEV) was studied at reaction temperatures between 350 and 450 °C using a combination of operando UV–vis spectroscopy and online gas chromatography. It was found that small differences in cage size, shape, and pore structure of the zeolite frameworks result in the generation of different hydrocarbon pool species. More specifically, it was found that the large cage of CHA results in the formation of a wide variety of hydrocarbon pool species, mostly alkylated benzenes and naphthalenes. In the DDR cage, 1-methylnaphthalene is preferentially formed, while the small LEV cage generally contains fewer hydrocarbon pool species. The nature and evolution of these hydrocarbon pool species was linked with the stage of the reaction using a multivariate analysis of the operando UV–vis spectra. In the 3-D pore network of CHA, the reaction temperature has only a minor effect on the performance of the MTO catalyst. However, for the 2-D pore networks of DDR and LEV, an increase in the applied reaction temperature resulted in a dramatic increase in catalytic activity. For all zeolites in this study, the role of the hydrocarbon species changes with reaction temperature. This effect is most clear in DDR, in which diamantane and 1-methylnaphthalene are deactivating species at a reaction temperature of 350 °C, whereas at higher temperatures diamantane formation is not observed and 1-methylnaphthalene is an active species. This results in a different amount and nature of coke species in the deactivated catalyst, depending on zeolite framework and reaction temperature. PMID:28603658

  18. Operando Grazing Incidence Small-Angle X-ray Scattering/X-ray Diffraction of Model Ordered Mesoporous Lithium-Ion Battery Anodes.

    Science.gov (United States)

    Bhaway, Sarang M; Qiang, Zhe; Xia, Yanfeng; Xia, Xuhui; Lee, Byeongdu; Yager, Kevin G; Zhang, Lihua; Kisslinger, Kim; Chen, Yu-Ming; Liu, Kewei; Zhu, Yu; Vogt, Bryan D

    2017-02-28

    Emergent lithium-ion (Li(+)) batteries commonly rely on nanostructuring of the active electrode materials to decrease the Li(+) ion diffusion path length and to accommodate the strains associated with the insertion and de-insertion of Li(+), but in many cases these nanostructures evolve during electrochemical charging-discharging. This change in the nanostructure can adversely impact performance, and challenges remain regarding how to control these changes from the perspective of morphological design. In order to address these questions, operando grazing-incidence small-angle X-ray scattering and X-ray diffraction (GISAXS/GIXD) were used to assess the structural evolution of a family of model ordered mesoporous NiCo2O4 anode films during battery operation. The pore dimensions were systematically varied and appear to impact the stability of the ordered nanostructure during the cycling. For the anodes with small mesopores (≈9 nm), the ordered nanostructure collapses during the first two charge-discharge cycles, as determined from GISAXS. This collapse is accompanied by irreversible Li-ion insertion within the oxide framework, determined from GIXD and irreversible capacity loss. Conversely, anodes with larger ordered mesopores (17-28 nm) mostly maintained their nanostructure through the first two cycles with reversible Li-ion insertion. During the second cycle, there was a small additional deformation of the mesostructure. This preservation of the ordered structure lead to significant improvement in capacity retention during these first two cycles; however, a gradual loss in the ordered nanostructure from continuing deformation of the ordered structure during additional charge-discharge cycles leads to capacity decay in battery performance. These multiscale operando measurements provide insight into how changes at the atomic scale (lithium insertion and de-insertion) are translated to the nanostructure during battery operation. Moreover, small changes in the

  19. Initial reduction of the NiO(100) surface in hydrogen.

    Science.gov (United States)

    Xu, Qiang; Cheah, Singfoong; Zhao, Yufeng

    2013-07-14

    The reduction of NiO in hydrogen, a reaction with many industrial applications, has not received sufficient attention from theoretical standpoint because the complexity of the material properties and the process present considerable computational challenges. We report here the results of a systematic study on the hydrogen reduction of an ideal NiO(100) surface that produces a water molecule and an NiO(100) surface with an oxygen vacancy, using the Hubbard U corrected density functional theory method, with some of the key results verified by the hybrid density functional method. The major findings are: (1) the O vacancy in the NiO(100) surface slab is stabilized in the subsurface layer, although the vacancy is likely to remain on the outermost surface layer because the barrier for O vacancy migration from the surface to the second layer is as high as 3.02 eV; (2) regarding the energetics of hydrogen interaction with the ideal NiO(100) surface, water formation, and concomitant reduction of NiO is favored at higher H coverage even though surface hydrogenation is energetically more favorable than water formation at lower H coverage; (3) kinetically, the pull-off of the surface oxygen atom and simultaneous activation of the nearby Ni atoms play key roles in hydrogen reduction of NiO(100); and (4) a dual role of hydrogen is revealed as both a reactant and a mediator, which reduces the maximum kinetic barrier from 2.41 eV to 1.86 eV.

  20. Catalytic activity of Ni-YSZ anodes in a single-chamber solid oxide fuel cell reactor

    Science.gov (United States)

    Savoie, Sylvio; Napporn, Teko W.; Morel, Bertrand; Meunier, Michel; Roberge, Réal

    The importance of heterogeneous catalysis in single-chamber solid oxide fuel cells (SC-SOFC) is universally recognized, but little studied. This work presents a thorough investigation of the catalytic activity of three Ni-YSZ half-cells in a well-described single-chamber reactor. One in-house electrolyte-supported and two commercially available anode-supported half-cells composed of anodes with thicknesses ranging from 50 μm to 1.52 mm are investigated. They are exposed to methane and oxygen gas mixtures within CH 4:O 2 flow rate ratios (R in) of 0.8-2.0 and furnace temperatures of 600-800 °C. The conversion of methane always results in the formation of syngas species (H 2 and CO). However, their yields vary considerably based on the individual anode, the operating temperature, and R in. The SC-reactor design and the presence of hot-spots at the reactor entrance bring the methane and oxygen conversion rates well above the limit expected from experiments carried out with anode half-cells only. Major variations in the H 2/CO ratio are observed. In lowering the temperature from 800 °C to 600 °C, it spreads from well below to well above the stoichiometric value of 2.0 expected for the partial oxidation reaction. To optimize the SC-SOFC any further, the findings stress the need to undertake even more catalytic studies of its electrode materials under actual structure and morphology as well as final reactor configuration.

  1. PRODUÇÃO DO ESPAÇO URBANO: CONDOMÍNIOS HORIZONTAIS E LOTEAMENTOS FECHADOS EM CUIABÁ-MT

    OpenAIRE

    da Silva, Vânia

    2012-01-01

    O presente texto analisa a produção recente do espaço urbano em Cuiabá - MT através da construção dos grandes empreendimentos imobiliários intitulados condomínios horizontais fechados. Os chamados condomínios horizontais fechados apresentam características de condomínios horizontais convencionais e de loteamentos. Condomínios e loteamentos são figuras jurídicas distintas, regidos por legislações diferentes, entretanto o que se observa é que muitas vezes os empreendimentos são instalados em de...

  2. Photoelectrochemical properties of mesoporous NiO x deposited on technical FTO via nanopowder sintering in conventional and plasma atmospheres.

    Science.gov (United States)

    Awais, Muhammad; Dowling, Denis D; Decker, Franco; Dini, Danilo

    2015-01-01

    Nanoporous nickel oxide (NiO x ) has been deposited with two different procedures of sintering (CS and RDS). Both samples display solid state oxidation at about 3.1 V vs Li+/Li. Upon sensitization of CS/RDS NiO x with erythrosine b (ERY), nickel oxide oxidation occurs at the same potential. Impedance spectroscopy revealed a higher charge transfer resistance for ERY-sensitized RDS NiO x with respect to sensitized CS NiO x . This was due to the chemisorption of a larger amount of ERY on RDS with respect to CS NiO x . Upon illumination the photoinduced charge transfer between ERY layer and NiO x could be observed only with oxidized CS. Photoelectrochemical effects of sensitized RDS NiO x were evidenced upon oxide reduction. With the addition of iodine RDS NiOx electrodes could give the reduction iodine → iodide in addition to the reduction of RDS NiO x . p-type dye sensitized solar cells were assembled with RDS NiO x photocathodes sensitized either by ERY or Fast Green. Resulting overall efficiencies ranged between 0.02 and 0.04 % upon irradiation with solar spectrum simulator (I in: 0.1 W cm(-2)).

  3. Enhanced gas sensing performance of electrospun Pt-functionalized NiO nanotubes with chemical and electronic sensitization.

    Science.gov (United States)

    Fu, Jiecai; Zhao, Changhui; Zhang, Junli; Peng, Yong; Xie, Erqing

    2013-08-14

    Pt-functionalized NiO composite nanotubes were synthesized by a simple electrospinning method, and their morphology, chemistry, and crystal structure have been characterized at the nanoscale. It was found that the Pt nanoparticles were dispersed uniformly in the NiO nanotubes, and the Pt-functionalized NiO composite nanotubes showed some dendritic structure in the body of nanotubes just like thorns growing in the nanotubes. Compared with the pristine NiO nanotube based gas sensor and other NiO-based gas sensors reported previously, the Pt-functionalized NiO composite nanotube based gas sensor showed substantially enhanced electrical responses to target gas (methane, hydrogen, acetone, and ethanol), especially ethanol. The NiO-Pt 0.7% composite nanotube based gas sensor displayed a response value of 20.85 at 100 ppm at ethanol and 200 °C, whereas the pristine NiO nanotube based gas sensor only showed a response of 2.06 under the same conditions. Moreover, the Pt-functionalized NiO composite nanotube based gas sensor demonstrated outstanding gas selectivity for ethanol against methane, hydrogen, and acetone. The reason for which the Pt-functionalized NiO composite nanotube based gas sensor obviously enhanced the gas sensing performance is attributed to the role of Pt on the chemical sensitization (catalytic oxidation) of target gases and the electronic sensitization (Fermi-level shifting) of NiO.

  4. Hydrogen sensor based on Au and YSZ/HgO/Hg electrode for in situ measurement of dissolved H2 in high-temperature and -pressure fluids.

    Science.gov (United States)

    Zhang, R H; Hu, S M; Zhang, X T; Wang, Y

    2008-11-15

    Gold as a hydrogen-sensing electrode for in situ measurement of dissolved H2 in aqueous solutions under extreme conditions is reported. The dissolved H2 sensor, constructed with a Au-based sensing element and coupled with a YSZ/HgO/Hg electrode, is well suited for determining dissolved H2 concentrations of aqueous fluids at elevated temperatures and pressures. The Au electrode is made of Au wire mounted in a quartz bar, which can be pressurized and heated in the high-pressure and -temperature conditions. The Au-YSZ sensor has been tested for its potential response to the concentrations of dissolved H2 in fluids by using a flow-through reactor at high temperatures up to 400 degrees C and pressures to 38 MPa. Good sensitivity and linear response between the hydrogen concentrations in the fluids and the H2 sensor potentials are reported for hydrogen gas in the concentration range of 0.1-0.001 M H2 in aqueous fluids at temperatures up to 340 degrees C and 30 MPa. Nernstian response of the cell potential to dissolved H2 in fluids was determined at 340 degrees C and 30 MPa, described as follows: DeltaE = 0.9444 + 0. 0603 log m H2 The experimental results indicate that the Au-YSZ/HgO/Hg cell can be used to measure the solubility of H2 in aqueous fluid at temperatures and pressures near to the critical state of water. Thus, this type of Au hydrogen sensor could be easily used for in situ measurement of H2 in hydrothermal fluids in a high-pressure vessel, or at midocean ridge, due to its structure of compression resistance.

  5. Determination of the mechanical properties and fracture mechanisms of YSZ and GDC for electrolyte-supported SOFCs by instrumented indentation test; Determinacion de las propiedades mecanicas y mecanismos de fractura de electrolitos soportados de YSZ y GDC mediante ensayos de indentacion instrumentada

    Energy Technology Data Exchange (ETDEWEB)

    Roa, J. J.; Morales, M.; Capdevila, X. G.; Segarra, M.

    2010-07-01

    The main purpose of this work is to evaluate the different mechanical properties and the different fracture mechanisms activated during the instrumented indentation process of the electrolytes based on Yttria stabilized zirconia (YSZ) and gadolinia doped ceria (GDC), for solid oxide fuel cells (SOFCs). Both materials, with a thickness of 200 {mu}m, were shaped by uniaxial pressing at 500 MPa, and sintered at 1400 degree centigrade. Mechanical properties such as hardness (H) and Young's modulus (E) have been studied at different penetration depths using the Oliver and Pharr equations. The different fracture mechanisms activated during the instrumented indentation process have been studied at constant penetration depth of 500 nm, performed with a diamond Berkovich tip indenter. The residual indentation imprints have been observed with atomic force microscopy (AFM). The hardness and Young's modulus for YSZ electrolytes are higher than for GDC materials, due to the different fracture mechanism activated during the indentation process. As a result, the electrolytes of YSZ presented trans- and intergranular fracture mechanisms, depending on the place of the residual indentation imprint (in the grain boundary or in the middle of the grain, respectively). However, the GDC electrolyte revealed radical cracks at the corners of the residual nano indentation imprints, thus producing a phenomenon known as chipping. (Author)

  6. The observation of chemiluminescent NiO* emissions in the laboratory and in the night airglow

    Directory of Open Access Journals (Sweden)

    A. L. Broadfoot

    2011-04-01

    Full Text Available The recent finding of an orange spectral feature in OSIRIS/Odin spectra of the night airglow near 85 km has raised interest in the origin of the emission. The feature was positively identified as the chemiluminescent FeO* emission where the iron is of meteoric origin. Since the meteorite source of atomic metals in the mesosphere contains both iron and nickel, with Ni being typically 6% of Fe, it is expected that faint emissions involving Ni should also be present in the night airglow. The present study summarizes the laboratory observations of chemiluminescent NiO* emissions and includes a search for the NiO* signature in the night airglow. A faint previously unidentified "continuum" extending longwave of 440 nm has been identified in night airglow spectra obtained with two space-borne limb viewing instruments and through a comparison with laboratory spectra this continuum is identified as arising from the NiO* emission. The FeO* and NiO* emissions both originate from a reaction of the metal atoms with mesospheric ozone and so support the presence of NiO* in the night airglow.

  7. Neem leaves mediated preparation of NiO nanoparticles and its magnetization, coercivity and antibacterial analysis

    Science.gov (United States)

    Helan, V.; Prince, J. Joseph; Al-Dhabi, Naif Abdullah; Arasu, Mariadhas Valan; Ayeshamariam, A.; Madhumitha, G.; Roopan, Selvaraj Mohana; Jayachandran, M.

    Nickel oxides nanoparticles (NiO NPs) were synthesized by biosynthesis method with the help of phytoconstituents present in the neem leaf. Further the synthesized NiO NPs were subjected for structural, optical, morphological and magnetic properties. The XRD patterns clearly infer the presence of polycrystalline nature of samples (0 1 0), (0 1 1) and (0 1 2) with hexagonal crystal phase. Morphological studies using Transmission Electron Microscope (TEM) reveals that the biosynthesized NiO NPs were in shape of oblong with 12 nm in size. Elemental analysis (EDAX) confirms the quantity of Ni is present at 51% and remaining O as 49% as well as the mass magnetization values of 61 emu/g are also recorded for NiO NPs and its coercivity values in the range of 0.2-0.4 of nanoparticles respectively. Finally the NiO NPs was studied for bacterial activity against Staphylococcus aureus (MTCC 1430) and followed by Escherichia coli (MTCC 739) by agar diffusion assay.

  8. Characterization of crystalline structure and morphology of NiO thin films.

    Science.gov (United States)

    Shin, Hyemin; Choi, Soo-Bin; Yu, Chung-Jong; Kim, Jae-Yong

    2011-05-01

    We investigated the relation of sputtering powers with structural and morphological properties of nickel oxide (NiO) thin films. NiO thin films were fabricated by using an rf-reactive sputtering method on Si(100) substrates with a Ni target in a partial pressure of oxygen and argon. The films were deposited by various rf-sputtering powers from 100 to 200 W at room temperature. The phases and crystalline structures of the deposited films were investigated by using grazing incident X-ray diffraction (XRD). The thickness and surface morphology of the films were investigated by using a field emission-scanning electron microscopy (FE-SEM). The different sputtering conditions drastically affected the crystallinity and the surface morphology of NiO thin films. A combined analysis of the data obtained from X-ray diffraction and SEM images demonstrates that the preferred orientation of NiO films tends to grow from (111) to (200) direction as increasing the sputtering power, which can be explained by in terms of the surface energy along the indexing plane in an fcc structure. As increasing the rf power, lattice constants decreased from 4.26 to 4.20 angstroms and samples became high-quality crystals. Under our experimental condition, NiO films prepared at 150 W with 20% partial pressure of oxygen and 7 cm distance from the sample to the target show the best quality of the crystal.

  9. Hexagonally-arranged-nanoporous and continuous NiO films with varying electrical conductivity

    Energy Technology Data Exchange (ETDEWEB)

    Gutiérrez, A., E-mail: a.gutierrez@uam.es [Departamento de Física Aplicada and Instituto de Ciencia de Materiales Nicolás Cabrera, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid (Spain); Domínguez-Cañizares, G. [Departamento de Física Aplicada and Instituto de Ciencia de Materiales Nicolás Cabrera, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid (Spain); Jiménez, J.A. [Centro Nacional de Investigaciones Metalúrgicas, CSIC, Avda Gregorio del Amo 8, E-28040 Madrid (Spain); Preda, I. [European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex 9 (France); Díaz-Fernández, D. [Departamento de Física Aplicada and Instituto de Ciencia de Materiales Nicolás Cabrera, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid (Spain); Jiménez-Villacorta, F. [Department of Chemical Engineering, Northeastern University, 360 Huntington Ave., Boston, MA 02115 (United States); Castro, G.R. [European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex 9 (France); Instituto de Ciencia de Materiales de Madrid, CSIC, Sor Juana Inés de la Cruz, 3, E-28049 Madrid (Spain); Chaboy, J. [Instituto de Ciencia de Materiales de Aragón, CSIC, and Departamento de Física de la Materia Condensada, Universidad de Zaragoza, E-50009 Zaragoza (Spain); Soriano, L. [Departamento de Física Aplicada and Instituto de Ciencia de Materiales Nicolás Cabrera, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid (Spain)

    2013-07-01

    Nickel oxide (NiO) thin films have been prepared by magnetron sputtering, with different Ar/O{sub 2} ratios in the plasma, on several substrates, including hexagonally arranged nanoporous anodic alumina membranes (AAM). The obtained films exhibit columnar growth, which makes it possible to preserve the hexagonal order of the AAM substrates in the NiO thin films. X ray diffraction patterns show a polycrystalline structure with a crystallographic texture that depends on the plasma composition. Additionally, the NiO lattice parameter increases with the oxygen content of the plasma. The presence of oxygen during deposition is responsible for these structural changes, as well as for an oxygen enrichment in the NiO films, which leads to changes in their electrical properties. The electrical resistivity of the films decreases with the oxygen content of the plasma, which suggests p-type conductivity due to oxygen enrichment in the NiO lattice. Indeed, an analysis of the EXAFS oscillations at the Ni–K edge confirms the lattice expansion and a decrease of the Ni–Ni coordination number when the oxygen content of the plasma increases, which points towards an increasing presence of Ni vacancies for larger values of the O{sub 2}/Ar ratio.

  10. Solvothermal synthesis and photocatalytic properties of NiO ultrathin nanosheets with porous structure

    Science.gov (United States)

    Qing, Zhang; Haixia, Liu; Huali, Li; Yu, Liu; Huayong, Zhang; Tianduo, Li

    2015-02-01

    Hierarchical NiO microspheres, composed of ultrathin nanosheets with porous structure, are prepared through a facile solvothermal route followed by a calcination process. First, the precursor Ni3(NO3)2(OH)4 hierarchical architectures assembled by irregular nanosheets were synthesized through urea assisted precipitation. Second, the NiO hierarchical architecture was obtained from the precursor by a simple calcination procedure without changing their morphologies. The resultant products were characterized by XRD, SEM, TEM, TG, FT-IR and BET analysis techniques. The XRD pattern showed that the sample exhibited a rocksalt cubic phase structure after calcined at 500 °C for 2 h. The SEM and TEM images demonstrated that the as-prepared NiO were microspheres composed of ultrathin nanosheets with porous structure. The catalytic efficiency of the NiO nanomaterials is evaluated by the photocatalytic degradation of methylene blue (MB). The obtained NiO displayed the excellent degradable ability and stable cyclability to MB dye, which may be attributed to its unique hierarchical characteristics: ultrathin-porous microstructure.

  11. Effect of defects on reaction of NiO surface with Pb-contained solution

    Science.gov (United States)

    Kim, Jongjin; Hou, Binyang; Park, Changyong; Bahn, Chi Bum; Hoffman, Jason; Black, Jennifer; Bhattacharya, Anand; Balke, Nina; Hong, Hawoong; Kim, Ji Hyun; Hong, Seungbum

    2017-01-01

    In order to understand the role of defects in chemical reactions, we used two types of samples, which are molecular beam epitaxy (MBE) grown NiO(001) film on Mg(001) substrate as the defect free NiO prototype and NiO grown on Ni(110) single crystal as the one with defects. In-situ observations for oxide-liquid interfacial structure and surface morphology were performed for both samples in water and Pb-contained solution using high-resolution X-ray reflectivity and atomic force microscopy. For the MBE grown NiO, no significant changes were detected in the high-resolution X-ray reflectivity data with monotonic increase in roughness. Meanwhile, in the case of native grown NiO on Ni(110), significant changes in both the morphology and atomistic structure at the interface were observed when immersed in water and Pb-contained solution. Our results provide simple and direct experimental evidence of the role of the defects in chemical reaction of oxide surfaces with both water and Pb-contained solution. PMID:28317881

  12. Synthesis and characterization of NiO nanopowder by sol-gel process

    Energy Technology Data Exchange (ETDEWEB)

    Ningsih, Sherly Kasuma Warda [Department of Chemistry, Faculty of Mathematics and Natural Sciences Padang State University, Kampus Air Tawar, Jl. Prof. Dr. Hamka, West Sumatera, 25161, Indonesia Email: sherly-kasuma@yahoo.com (Indonesia)

    2015-09-30

    Preparation of nickel oxide (NiO) nanopowder by sol-gel process has been studied. NiO nanopowders were obtained by sol-gel method by using nickel nitrate hexahydrate and sodium hydroxide and aquadest were used as precursor, agent precipitator and solvent, respectively. The powders were formed by drying at 110°C and followed by heating in the furnace at 400°C for 1.5 hours. The product was obtained black powder. The product was characterized by Energy Dispesive X-ray Fluorescence (ED-XRF), X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). The ED-XRF pattern shows the composition of NiO produced was 97.1%. The XRD pattern showed NiO forms were produced generally in monoclinic stucture. The crystalline size of NiO was obtained in the range 40-85 nm. SEM micrograph clearly showed that powder had a spherical with uniform distribution size is 0.1-1.0 µm approximately.

  13. Data acquisition system based on the Nios II for a CCD camera

    Science.gov (United States)

    Li, Binhua; Hu, Keliang; Wang, Chunrong; Liu, Yangbing; He, Chun

    2006-06-01

    The FPGA with Avalon Bus architecture and Nios soft-core processor developed by Altera Corporation is an advanced embedded solution for control and interface systems. A CCD data acquisition system with an Ethernet terminal port based on the TCP/IP protocol is implemented in NAOC, which is composed of a piece of interface board with an Altera's FPGA, 32MB SDRAM and some other accessory devices integrated on it, and two packages of control software used in the Nios II embedded processor and the remote host PC respectively. The system is used to replace a 7200 series image acquisition card which is inserted in a control and data acquisition PC, and to download commands to an existing CCD camera and collect image data from the camera to the PC. The embedded chip in the system is a Cyclone FPGA with a configurable Nios II soft-core processor. Hardware structure of the system, configuration for the embedded soft-core processor, and peripherals of the processor in the PFGA are described. The C program run in the Nios II embedded system is built in the Nios II IDE kits and the C++ program used in the PC is developed in the Microsoft's Visual C++ environment. Some key techniques in design and implementation of the C and VC++ programs are presented, including the downloading of the camera commands, initialization of the camera, DMA control, TCP/IP communication and UDP data uploading.

  14. Morphology-dependent NiO modified glassy carbon electrode surface for lead(II) and cadmium(II) detection

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xuewu [School of Mechanical and Electronic Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070 (China); Wen, Hao [School of Materials Science and Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070 (China); Fu, Qiang; Peng, Dai [Wuhan Institute of Marine Electric Propulsion, Wuhan 430070 (China); Yu, Jingui [School of Mechanical and Electronic Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070 (China); Zhang, Qiaoxin, E-mail: qiaoxinzhang1220@163.com [School of Mechanical and Electronic Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070 (China); Huang, Xingjiu [School of Mechanical and Electronic Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070 (China)

    2016-02-15

    Graphical abstract: Glassy carbon electrode surfaces have been modified with rods NiO, flakes NiO and balls NiO prepared via hydrothermal synthesis method for Pb(II) and Cd(II) detection by using the square wave anodic stripping voltammetry, among which the balls NiO modified electrode can achieve the optimal electrochemical detection ability for its enhanced electron transfer capacity, large BET surface area and strong adsorption capacity on surface. - Highlights: • Glassy carbon electrode surface was modified with NiO for lead(II) and cadmium(II) detection. • Surface detection effect was evaluated by detection limit, sensitivity and linear relativity. • Balls NiO modified electrode showed better electrochemical detection ability. • Lager BET surface area of NiO made electrode surface excellent electron transfer capacity. • Balls NiO modified electrode exhibited superior adsorption capacity and detection stability. - Abstract: Glassy carbon electrode (GCE) surfaces have been modified with different NiO morphologies consisting of rods NiO, flakes NiO and balls NiO prepared via the hydrothermal synthesis method for Pb(II) and Cd(II) detection by using the square wave anodic stripping voltammetry (SWASV). Meanwhile, the typical cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), BET surface area and adsorption property of the modified electrode surfaces have been investigated to evaluate their electrochemical detection effect. Results show that balls NiO modified GCE can get the optimal detection ability for its highest detection sensitivity to Pb(II) (13.46 A M{sup −1}) and Cd(II) (5.10 A M{sup −1}), the lowest detection limit (DL) to Pb(II) (0.08 μM) and Cd(II) (0.07 μM) as well as the superior linear relativity. In addition, an enhanced current at redox peaks, lower electron transfer resistance, larger BET surface area and stronger adsorption capacity have been confirmed for the balls NiO modified GCE surface. Finally, excellent

  15. Wetting of sodium on β''-Al2O3/YSZ composites for low temperature planar sodium-metal halide batteries

    Energy Technology Data Exchange (ETDEWEB)

    Reed, David; Coffey, Greg; Mast, Eric; Canfield, Nathan; Mansurov, Jirgal; Lu, Xiaochuan; Sprenkle, Vince

    2013-04-01

    Wetting of Na on B”-Al2O3/YSZ composites was investigated using the sessile drop technique. The effects of moisture and surface preparation were studied at low temperatures. Electrical conductivity of Na/B”-Al2O3-YSZ/Na cells was also investigated at low temperatures and correlated to the wetting behavior. The use of planar B”-Al2O3 substrates at low temperature with low cost polymeric seals is realized due to improved wetting at low temperature and conductivity values consistent with the literature.

  16. Polarized neutron powder diffraction studies of antiferromagnetic order in bulk and nanoparticle NiO

    DEFF Research Database (Denmark)

    Brok, Erik; Lefmann, Kim; Deen, Pascale P.;

    2015-01-01

    surface contribution to the magnetic anisotropy. Here we explore the potential use of polarized neutron diffraction to reveal the magnetic structure in NiO bulk and nanoparticle powders by applying the XYZ-polarization analysis method. Our investigations address in particular the spin orientation in bulk...... NiO and platelet-shaped NiO nanoparticles with thickness from greater than 200 nm down to 2.0 nm. The advantage of the applied method is that it is able to clearly separate the structural, the magnetic, and the spin-incoherent scattering signals for all particle sizes. For platelet-shaped particles......In many materials it remains a challenge to reveal the nature of magnetic correlations, including antiferromagnetism and spin disorder. Revealing the spin structure in magnetic nanoparticles is further complicated by the large incoherent neutron scattering cross section from water adsorbed...

  17. Optical second harmonic generation induced by picosecond terahertz pulses in centrosymmetric antiferromagnet NiO

    Science.gov (United States)

    Ovchinnikov, A. V.; Chefonov, O. V.; Agranat, M. B.; Grishunin, K. A.; Il'in, N. A.; Pisarev, R. V.; Kimel, A. V.; Kalashnikova, A. M.

    2016-10-01

    Optical second harmonic generation at the photon energy of 2ℏω = 2eV in the model centrosymmetric antiferromagnet NiO irradiated with picosecond terahertz pulses (0.4-2.5 THz) at room temperature is detected. The analysis of experimental results shows that induced optical second harmonic generation at the moment of the impact of a terahertz pulse arises through the electric dipole mechanism of the interaction of the electric field of a pump pulse with the electron subsystem of NiO. Temporal changes in optical second harmonic generation during 7 ps after the action of the pulse are also of an electric dipole origin and are determined by the effects of propagation of the terahertz pulse in a NiO platelet. Coherent oscillations of spins at the antiferromagnetic resonance frequency induced by the magnetic component of the terahertz pulse induce a relatively weak modulation of magnetic dipole optical second harmonic generation.

  18. CdTeO3 Deposited Mesoporous NiO Photocathode for a Solar Cell

    Directory of Open Access Journals (Sweden)

    Chuan Zhao

    2014-01-01

    Full Text Available Semiconductor sensitized NiO photocathodes have been fabricated by successive ionic layer adsorption and reaction (SILAR method depositing CdTeO3 quantum dots onto mesoscopic NiO films. A solar cell using CdTeO3 deposited NiO mesoporous photocathode has been fabricated. It yields a photovoltage of 103.7 mV and a short-circuit current density of 0.364 mA/cm2. The incident photon to current conversion efficiency (IPCE value is found to be 12% for the newly designed NiO/CdTeO3 solar cell. It shows that the p-type NiO/CdTeO3 structure could be successfully utilized to fabricate p-type solar cell.

  19. Catalytic NiO Filter Supported on Carbon Fiber for Oxidation of Volatile Organic Compounds

    Energy Technology Data Exchange (ETDEWEB)

    Sim, Jong Ki; Seo, Hyun Ook; Jeong, Myunggeun; Kim, Kwangdae; Kim, Young Dok [Sungkyunkwan Univ., Suwon (Korea, Republic of); Lim, Dong Chan [Korea Institute of Materials Science, Changwon (Korea, Republic of)

    2013-07-15

    Carbon-fiber-supported NiO catalytic filters for oxidation of volatile organic compounds were prepared by electroless Ni-P plating and subsequent annealing processes. Surface structure and crystallinity of NiO film on carbon fiber could be modified by post-annealing at different temperatures (500 and 650 .deg. C). Catalytic thermal decompositions of toluene over these catalytic filters were investigated. 500 .deg. C-annealed sample showed a higher catalytic reactivity toward toluene decomposition than 650 .deg. C-annealed one under same conditions, despite of its lower surface area and toluene adsorption capacity. X-ray diffraction and X-ray photoelectron spectroscopy studies suggest that amorphous structures of NiO on 500 .deg. C-annealed catalyst caused the higher reactivity for oxidation of toluene than that of 650 .deg. C-annealed sample with a higher crystallinity.

  20. Acquisition, data retrieval, interlock and control systems for the negative ion source NIO1

    Science.gov (United States)

    Serianni, G.; Baltador, C.; Barbato, P.; Baseggio, L.; Cavazzana, R.; Cavenago, M.; De Muri, M.; Laterza, B.; Migliorato, L.; Molon, F.; Moro, G.; Ravarotto, D.; Pasqualotto, R.; Patton, T.; Recchia, M.; Taliercio, C.; Veltri, P.

    2017-08-01

    The NIO1 (Negative Ion Optimization, phase 1) experiment is a versatile test bench with goal of delivering a negative hydrogen beam current of 135mA accelerated to -60kV and divided into 9 beamlets. NIO1 is operated by Consorzio RFX and INFN in the framework of the activities aimed at the enhancement of negative ion sources for production of large ion beams for plasma heating in nuclear fusion devices and accelerator applications. For the NIO1 device an Acquisition, Data Retrieval, Interlock and Control (ADRIC) system was realised. The present paper gives a detailed description of the overall structure of ADRIC, which integrates together the various components; the single parts are also described, particularly highlighting the adoption of novel equipment. A special asset of this system is its flexibility when adding new components.

  1. Background gas density and beam losses in NIO1 beam source

    Energy Technology Data Exchange (ETDEWEB)

    Sartori, E., E-mail: emanuele.sartori@igi.cnr.it; Veltri, P.; Serianni, G. [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), C.so Stati Uniti 4, 35127 Padova (Italy); Cavenago, M. [INFN-LNL, v.le dell’Università 2, I-35020 Legnaro (PD) (Italy)

    2016-02-15

    NIO1 (Negative Ion Optimization 1) is a versatile ion source designed to study the physics of production and acceleration of H- beams up to 60 keV. In ion sources, the gas is steadily injected in the plasma source to sustain the discharge, while high vacuum is maintained by a dedicated pumping system located in the vessel. In this paper, the three dimensional gas flow in NIO1 is studied in the molecular flow regime by the Avocado code. The analysis of the gas density profile along the accelerator considers the influence of effective gas temperature in the source, of the gas temperature accommodation by collisions at walls, and of the gas particle mass. The calculated source and vessel pressures are compared with experimental measurements in NIO1 during steady gas injection.

  2. Background gas density and beam losses in NIO1 beam source

    Science.gov (United States)

    Sartori, E.; Veltri, P.; Cavenago, M.; Serianni, G.

    2016-02-01

    NIO1 (Negative Ion Optimization 1) is a versatile ion source designed to study the physics of production and acceleration of H- beams up to 60 keV. In ion sources, the gas is steadily injected in the plasma source to sustain the discharge, while high vacuum is maintained by a dedicated pumping system located in the vessel. In this paper, the three dimensional gas flow in NIO1 is studied in the molecular flow regime by the Avocado code. The analysis of the gas density profile along the accelerator considers the influence of effective gas temperature in the source, of the gas temperature accommodation by collisions at walls, and of the gas particle mass. The calculated source and vessel pressures are compared with experimental measurements in NIO1 during steady gas injection.

  3. Properties of Li-Doped NiO Thin Films Prepared by RF-Magnetron Sputtering.

    Science.gov (United States)

    Kwon, Ho-Beom; Han, Joo-Hwan; Lee, Hee Young; Lee, Jai-Yeoul

    2016-02-01

    Li-doped NiO thin films were deposited on glass and c-axis (0001) sapphire single crystal substrates by radio frequency (RF)-niagnetron sputtering. The effects of the type of substrate, substrate temperature and atmosphere on the structural, electrical and optical properties of the NiO thin films were examined. The electrical conductivity of the NiO thin films depends on the type of substrate, substrate temperature and oxygen atmosphere. The electrical conductivity of the thin films on the glass and sapphire substrates was improved by the introduction of oxygen and decreased with increasing substrate temperature. The optical transmittance decreased with the introduction of oxygen and increased with increasing substrate temperature.

  4. On the similarity of the bonding in NiS and NiO

    Science.gov (United States)

    Bauschlicher, C. W., Jr.

    1985-01-01

    The bonding in NiS is found to be quite similar to that in NiO, having an ionic contribution arising from the donation of the Ni 4s electron to the S atom and a covalent component arising from bonds between the Ni 3d and the S 3p. The one-electron d bonds are found to be of equal strength for NiO and NiS, but the two-electron d bonds are weaker for NiS.

  5. Stripe conductivity in La1.775Sr0.225NiO4

    Science.gov (United States)

    Pashkevich; Blinkin; Gnezdilov; Tsapenko; Eremenko; Lemmens; Fischer; Grove; Guntherodt; Degiorgi; Wachter; Tranquada; Buttrey

    2000-04-24

    We report Raman light-scattering and optical conductivity measurements on a single crystal of La1.775Sr0.225NiO4 which exhibits incommensurate charge-stripe order. The extra phonon peaks induced by stripe order can be understood in terms of the energies of phonons that occur at the charge-order wave vector Q(c). A strong Fano antiresonance for a Ni-O bond-stretching mode provides clear evidence for finite dynamical conductivity within the charge stripes.

  6. Stripe Conductivity in La1.775Sr0.225NiO4

    Science.gov (United States)

    Pashkevich, Yu. G.; Blinkin, V. A.; Gnezdilov, V. P.; Tsapenko, V. V.; Eremenko, V. V.; Lemmens, P.; Fischer, M.; Grove, M.; Güntherodt, G.; Degiorgi, L.; Wachter, P.; Tranquada, J. M.; Buttrey, D. J.

    2000-04-01

    We report Raman light-scattering and optical conductivity measurements on a single crystal of La1.775Sr0.225NiO4 which exhibits incommensurate charge-stripe order. The extra phonon peaks induced by stripe order can be understood in terms of the energies of phonons that occur at the charge-order wave vector Qc. A strong Fano antiresonance for a Ni-O bond-stretching mode provides clear evidence for finite dynamical conductivity within the charge stripes.

  7. Exchange bias in finite sized NiO nanoparticles with Ni clusters

    Science.gov (United States)

    Gandhi, Ashish Chhaganlal; Lin, Jauyn Grace

    2017-02-01

    Structural and magnetic properties of finite sized NiO nanoparticles are investigated with synchrotron X-ray diffraction (XRD), transmission electron microscopy, magnetometer and ferromagnetic resonance (FMR) spectroscopy. A minor Ni phase is detected with synchrotron XRD, attributed to the oxygen defects in the NiO core. A considerable exchange bias of 100 Oe is observed at 50 K and it drops abruptly and vanishes above 150 K, in association with the reduction of frozen spins. FMR data indicate a strong interaction between ferromagnetic (FM) and antiferromagnetic (AFM) phases below 150 K, consistent with the picture of isolated FM clusters in AFM matrix.

  8. Tratamento de efluentes resultantes da exploração de urânio

    OpenAIRE

    Sequeira, Cláudia Derboven

    2008-01-01

    Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia do Ambiente, Perfil Sanitária Após um século de exploração mineira em Portugal, nomeadamente de componentes radioactivos, como o urânio, rádio, polónio, entre outros, resultaram muitas minas, escombreiras de minério pobre e de estéreis, bacias de rejeitados, eiras de efluentes e lamas resultantes de processos de decantação de efluentes. Por ...

  9. The effect of the nanosize on surface properties of NiO nanoparticles for the adsorption of Quinolin-65.

    Science.gov (United States)

    Marei, Nedal N; Nassar, Nashaat N; Vitale, Gerardo

    2016-03-07

    Using Quinolin-65 (Q-65) as a model-adsorbing compound for polar heavy hydrocarbons, the nanosize effect of NiO nanoparticles on the adsorption of Q-65 was investigated. Different-sized NiO nanoparticles with sizes between 5 and 80 nm were prepared by the controlled thermal dehydroxylation of Ni(OH)2. The properties of the nanoparticles were characterized using XRD, BET, FTIR, HRTEM and TGA. The effects of the nanosize on the textural properties, the shape and the morphology were studied. The adsorption of Q-65 molecules onto different-sized nanoparticles was tested in toluene-based solutions. On a normalized surface area basis, the number of Q-65 molecules adsorbed per nm(2) of the NiO surface was the highest for NiO nanoparticles of size 80 nm, while that for 5 nm sized NiO nanoparticles was the lowest. Excitingly, the adsorption capacity of other NiO sizes varied from loading suggesting different adsorption behavior, which exhibits the significance of textural properties during the adsorption of Q-65. Computational modeling of the interaction between the Q-65 molecule and the NiO nanoparticle surface was carried out to get more understanding of its adsorption behavior. A number of factors contributing to the enhanced adsorption capacity of nanoscale NiO were determined. These include surface reactivity, topology, morphology and textural properties.

  10. Influence of microwave power on the preparation of NiO nanoflakes for enhanced magnetic and supercapacitor applications.

    Science.gov (United States)

    Anandha Babu, G; Ravi, G; Mahalingam, T; Kumaresavanji, M; Hayakawa, Y

    2015-03-14

    Nanoflake-structured NiO were synthesized by a microwave assisted method without the use of additives. The cubic phase of NiO nanoparticles with increasing crystalline nature for higher microwave power is ascertained by X-ray diffraction studies. Previous reports revealed that hexagonally structured β-Ni(OH)2 was completely transferred into the cubic phase of NiO around 350 °C, confirmed by using thermal analysis (TG/DTA). In our present work, the size and morphology of nanoparticles are ascertained from transmission electron microscopy (TEM) analysis. Flake-like morphology with uniform size, shape and less agglomerated structure formation is obtained for 900 and 600 W of microwave power used for the synthesis of NiO samples. The effect of microwave power used for the synthesis of NiO nanoflakes was analyzed by studying the magnetic and electrochemical behavior of NiO nanoflakes. Room temperature magnetic measurements revealed the small ferromagnetic nature of NiO nanoparticles. It was observed that the samples synthesized at higher microwave power exhibited divergence behavior below 300 K in FC and ZFC measurements, which results superparamagnetic behavior. An enhanced supercapacitor performance with higher specific capacitance values was determined for NiO nanoflake samples synthesized at (25)600 W and 900 W of microwave power.

  11. The electronic structure of NiO for Ni 3s-hole states including full orbital relaxation and localization

    NARCIS (Netherlands)

    Bagus, Paul S.; Broer, R; Graaf, C. de; Nieuwpoort, W.C.

    1999-01-01

    The electronic structure of NiO, with emphasis on the Ni 3s-hole ionic states, is studied using non-orthogonal configuration interaction, NOCI, wavefunctions for an NiO6 model of the crystal. Orbital sets are relaxed, or optimized, separately for each configuration used in the NOCI and orbital

  12. Effects of cobalt addition on the catalytic activity of the Ni-YSZ anode functional layer and the electrochemical performance of solid oxide fuel cells.

    Science.gov (United States)

    Guo, Ting; Dong, Xiaolei; Shirolkar, Mandar M; Song, Xiao; Wang, Meng; Zhang, Lei; Li, Ming; Wang, Haiqian

    2014-09-24

    The effects of cobalt (Co) addition in the Ni-YSZ anode functional layer (AFL) on the structure and electrochemical performance of solid oxide fuel cells (SOFCs) are investigated. X-ray diffraction (XRD) analyses confirmed that the active metallic phase is a Ni(1-x)Co(x) alloy under the operation conditions of the SOFC. Scanning electron microscopy (SEM) observations indicate that the grain size of Ni(1-x)Co(x) increases with increasing Co content. Thermogravimetric analyses on the reduction of the Ni(1-x)Co(x)O-YSZ powders show that there are two processes: the chemical-reaction-controlled process and the diffusion-controlled process. It is found that the reduction peak corresponding to the chemical-reaction-controlled process in the DTG curves moves toward lower temperatures with increasing Co content, suggesting that the catalytic activity of Ni(1-x)Co(x) is enhanced by the doping of Co. It is observed that the SOFC shows the best performance at x = 0.03, and the corresponding maximum power densities are 445, 651, and 815 mW cm(-2) at 700, 750, and 800 °C, respectively. The dependence of the SOFC performance on the Co content can be attributed to the competing results between the decreased three-phase-boundary length in the AFL and the enhanced catalytic activity of the Ni(1-x)Co(x) phase with increasing Co content.

  13. To Evaluate the Application of Alkoxide Sol-Gel Method in Fabrication of 3YSZ-MWCNTs Nanocomposites, in an Attempt to Improve Its Mechanical Properties

    Directory of Open Access Journals (Sweden)

    Ali Ahmadi

    2014-01-01

    Full Text Available In the present research work, fabrication of YSZ-CNTs composite system through alkoxide sol-gel processing was evaluated, in an attempt to improve its mechanical properties. Nanocomposites containing 0.5–2 wt% MWCNTs were then fabricated through the hydrolysis and condensation processing of the solution mixtures containing alkoxide and inorganic precursors along with the functionalized CNTs under basic condition and its final sintering by the SPS technique at 1400°C. Results showed the formation of a nanocomposite powder based on pure 3YSZ matrix, with well dispersion of CNTs and its good adhesion to the matrix particles in composite containing 0.5 wt% CNTs. The fracture toughness of sintered samples showed around 24% increase for the composite containing 0.5 wt% CNTs. The fracture toughness, hardness, and density decreased due to the agglomeration of CNTs over 0.5 wt%. Toughening mechanisms including pullout and crack bridging were observed on the polished and fractured surfaces.

  14. Characterization of Pd catalyst-electrodes deposited on YSZ: Influence of the preparation technique and the presence of a ceria interlayer

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez-Borja, Carmen, E-mail: Carmen.JBorja@uclm.es [Departamento de Ingenieria Quimica, Facultad de Ciencias Quimicas, Universidad de Castilla-La Mancha. Avenida Camilo Jose Cela 12, 13071 Ciudad Real (Spain); Matei, Florina [Department of Petroleum Processing Engineering and Environmental Protection, Petroleum - Gas University of Ploiesti (Romania); Dorado, Fernando; Valverde, Jose Luis [Departamento de Ingenieria Quimica, Facultad de Ciencias Quimicas, Universidad de Castilla-La Mancha. Avenida Camilo Jose Cela 12, 13071 Ciudad Real (Spain)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer Impregnation of palladium over YSZ led to more dispersed films. Black-Right-Pointing-Pointer XPS spectra indicated electron deficient Pd{sup 2+} species on the surface of palladium films. Black-Right-Pointing-Pointer Impregnated palladium films were more active than those prepared by paste deposition Black-Right-Pointing-Pointer The addition of a CeO{sub 2} interlayer enhanced the catalytic rate for the impregnated samples. - Abstract: Palladium catalyst-electrodes supported on Y{sub 2}O{sub 3}-stabilized-ZrO{sub 2} (YSZ) prepared either by paste deposition or wet impregnation technique were characterized using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found a strong dependence of the catalytic film preparation technique as well as of the presence of a ceria interlayer between the palladium film and the solid electrolyte on the catalytic activity towards methane oxidation. Impregnated palladium films were found to be more active than films prepared by paste deposition. Besides, the addition of ceria allowed stabilizing the palladium active phase for methane oxidation.

  15. Oxygen permeation flux through 10Sc1YSZ-MnCo2O4 asymmetric membranes prepared by two-step sintering

    DEFF Research Database (Denmark)

    Pirou, Stéven; Gurauskis, Jonas; Gil, Vanesa;

    2016-01-01

    Asymmetric membranes based on a dual phase composite consisting of (Y2O3)0.01(Sc2O3)0.10(ZrO2)0.89 (10Sc1YSZ) as ionic conductor and MnCo2O4 as electronic conductor were prepared and characterized with respect to sinterability, microstructure and oxygen transport properties. The composite membranes...... were prepared by tape casting, lamination and fired in a two-step sintering process. Microstructural analysis showed that a gastight thin membrane layer with the desired ratio of ionic/electronic conducting phases could be fabricated. Oxygen permeation fluxes across the 10SclYSZ/MnCo2O4 (70/30 vol......%) composite membrane were measured from 750 to 940 degrees C using air or pure oxygen as feed gases and N2 or CO2 as sweep gases. Fluxes up to 2.3 mlN min-1 cm-2 were obtained for the 7 μm thick membrane. A degradation test over 1730 h showed an initial degradation of 21% during the first 1100 h after which...

  16. Improving the Thermal Shock Resistance of Thermal Barrier Coatings Through Formation of an In Situ YSZ/Al2O3 Composite via Laser Cladding

    Science.gov (United States)

    Soleimanipour, Zohre; Baghshahi, Saeid; Shoja-razavi, Reza

    2017-04-01

    In the present study, laser cladding of alumina on the top surface of YSZ thermal barrier coatings (TBC) was conducted via Nd:YAG pulsed laser. The thermal shock behavior of the TBC before and after laser cladding was modified by heating at 1000 °C for 15 min and quenching in cold water. Phase analysis, microstructural evaluation and elemental analysis were performed using x-ray diffractometry, scanning electron microscopy (SEM), and energy-dispersive spectroscopy. The results of thermal shock tests indicated that the failure in the conventional YSZ (not laser clad) and the laser clad coatings happened after 200 and 270 cycles, respectively. The SEM images of the samples showed that delamination and spallation occurred in both coatings as the main mechanism of failure. Formation of TGO was also observed in the fractured cross section of the samples, which is also a main reason for degradation. Thermal shock resistance in the laser clad coatings improved about 35% after cladding. The improvement is due to the presence of continuous network cracks perpendicular to the surface in the clad layer and also the thermal stability and high melting point of alumina in Al2O3/ZrO2 composite.

  17. Serial port communication between PC and NIOS II based on Delphi%基于Delphi的PC与NIOS II的串行通信

    Institute of Scientific and Technical Information of China (English)

    卞小林; 王瑛剑; 杨智

    2008-01-01

    在比较SOPC与单片机的基础上,介绍了NIOS II串行通信接口以及Delphi下利用Spcomm控件实现串行通信的便利性.搭建了NIOS II软核处理器与上位机RS232串行通信电平转换电路,给出了下位机串行通信初始化代码.为了增强通信过程中的抗干扰能力,方案中设计定义了通信信息协议,并给出了具体上下位机信息的处理过程.实际应用表明,该方案有着很好的容错性与稳定性.

  18. 一种基于NiosII软核的自适应滤波器实现%The Realization of self-adapting filter based on Nios II Soft Processor

    Institute of Scientific and Technical Information of China (English)

    杨秀增

    2013-01-01

      为了有效地滤除心电信号的50Hz工频干扰,设计一种基于NiosII的自适应滤波器。利用QuartusII8.0开发工具进行硬件系统的开发;利用NiosII作为运算器来实现自适应滤波器算法;采用了自定义浮点指令的方法,提高滤波速度。测试了基于Nios II/e、Nios II/s和Nios II/f三种CPU的自适应滤波器性能,测试结果表明,三种自适应滤波器滤波效果良好,执行速度比用软件实现的要都快10倍以上。%  A kind of self-adapting filter based on FPGA is designed to filter the undesired 50Hz power signal in the ECG signal .Quartus II 8.0 is used to develop the hardware of this filter.The Nios II processor is adoped to implement adaptive filter algorithm in design,and the custom floating-point instruction is used to accelerated the execution speed of adaptive filtering algorithm.Three different self_adaption filters with diffferent Nios II,such asNios II/e、Nios II/s和Nios II/f are tested in the paper.Testing results show that the filtering effects of there self-adapting filters are good,and the execution speed is faster more 10 times than software machine.

  19. SOPC intelligent temperature transmitter based on Nios Ⅱ%基于软核Nios Ⅱ的SOPC智能温度变送器

    Institute of Scientific and Technical Information of China (English)

    王延年; 邓毓

    2012-01-01

    介绍了一种基于Nios Ⅱ软核处理器的智能温度变送器的设计方案,该变送器具有接受各种型号的热电阻、热电偶和毫伏信号,热电偶冷端温度补偿,输入输出信号零点满度自校准,信号状态自检测,上位对其内部参数设定等功能.此方案利用了SOPC技术的特点和Nios Ⅱ自定制指令功能,相比传统的单片机和DSP方案,它具有数据处理速度快、存储空间小、资源配置合理、集成度高和开发周期短等优点.通过实验对此方案进行了验证.%This paper introduces a kind of intelligent temperature transmitter based on Nios II. This transmitter has many functions that it can accept various types of RTD,thermocouple and millivolt signals,it can compensate the cold end of the thermocouple,adjust the input and output signals,it can detech the status of signals and set the internal parameters by PC. This scheme use the characteristics of SOPC technology and the function of Nios II custom instructions, Compared with the traditional scheme of SCM and DSP, this transmitter has the advantages that it can process data quickly,and has smaller storage space, reasonable resource configuration, higer integration and shorter development period. This scheme is verified by experiment.

  20. Human-machine Interface Design Using Nios II and CGI%使用Nios II实现的CGI嵌入式网络人机交互接口

    Institute of Scientific and Technical Information of China (English)

    崔巍; 王长松; 巩宪锋

    2008-01-01

    阐述了一种嵌入式网络人机交互接口的设计方法.以Nios II为硬件平台,详细探讨了在uClinux-dist中如何配置Boa网页服务器程序用于处理CGI程序,并编写了一个CGI程序来演示这种人机交互接口.

  1. Design of Colorimeter Control System Based on NIOS Ⅱ%基于Nios Ⅱ的色差仪控制系统

    Institute of Scientific and Technical Information of China (English)

    刘艳翠; 彭俊

    2011-01-01

    根据工业对颜色测量的需求,设计一种基于NiosⅡ技术并具有无线传输功能的色差仪.色差仪控制系统采用内部嵌入NiosⅡ软核处理器的FPGA,在软核外围添加A/D控制模块、矩阵键盘控制模块、液晶显示屏控制模块和射频传输控制模块,用以对颜色信号进行采集、处理、存储、显示和无线传输.论文详细阐述NiosⅡ软核的定制,A/D控制模块和射频无线传输模块的程序设计思路和仿真波形.%According to the demand of industry for measuring color,this paper designed a sort of colorimeter based on Nios II and provided with wireless conmunication function. The control system of colorimeter adopted the FPGA embeded Nios II. AD control module, matrix keyboard module, LCD display module and radio frequency transmission control module were around the NiosII to collect,process,store,display and wireless transfer the signal of color. The paper explained the configure of Nios II and the program designing and simulation of A/D control module and radio frequency wireless transmission module in detail.

  2. In-Plane Crystallinity Effect on the Unipolar Resistance Switching Behavior of NiO Thin Film.

    Science.gov (United States)

    Kim, Il Tae; Hur, Jaehyun; Chae, Seung Chul

    2016-02-01

    We report on the resistance switching behavior of high quality NiO thin films grown on Pt(111)/SiOx/Si and Pt(111)/Al2O3 crystals. Polarity independent resistance switching, i.e., unipolar resistance switching exhibited a substrate crystallinity dependence during the resistance switching. The unipolar resistance switching was observed commonly in NiO film grown on both substrates. High resistance state of NiO thin film without in-plane crystallinity showed higher resistance than that of NiO films with in-plane crystallinity. The NiO thin film without in-plane crystallinity also required high set voltages for the resistance switching from high resistance state to low resistance state and showed nonlinear I-V characteristics at high voltage region before the resistance switching.

  3. Preparation and characterization of highly ordered NiO nanowire arrays by sol-gel template method

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Highly ordered nickel monoxide (NiO) nanowire arrays were fabricated by sol-gel synthesis within the pores of anodic alumina membrane (AAM).Scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) were used to characterize the topography and crystalloid structure of NiO nanowire arrays.The length and diameter of the NiO nanowires depended on the thickness of the AAM and the diameter of the pores.The results indicated that the NiO nanowires were uniformly assembled into the ordered nanopores of the AAM and paralleled to each other.Nickel monoxide nanotubes were also fabricated with the same method by changing the immersing time.This new method to prepare NiO nanowire arrays may be important from gas sensors to various engineering materials.

  4. TiO2-NiO p-n nanocomposite with enhanced sonophotocatalytic activity under diffused sunlight.

    Science.gov (United States)

    Vinoth, R; Karthik, P; Devan, K; Neppolian, B; Ashokkumar, Muthupandian

    2017-03-01

    TiO2-NiO composites with p-n junction were developed by assembling p-type NiO on n-type TiO2 using ultrasound assisted wet impregnation method. The sonophotocatalytic efficiencies of pure TiO2 and TiO2-NiO composites were evaluated under diffused sunlight using methyl orange (MO) as a model pollutant. The impregnation of NiO nanoparticles on TiO2 considerably enhanced the optical absorption in visible region (500-800nm) due to the formation of p-n junctions at the interface between TiO2 and NiO. The internal electric field induced by the p-n junction led to effective separation of electron-hole pairs and thereby generating a large amount of reactive species for the degradation of MO. The individual effect of ultrasound and diffused sunlight for the degradation of MO was found to be 30% and 6%, respectively. A synergy of 4.8 fold was achieved when ultrasound was combined with photocatalytic degradation process in the presence of diffused sunlight. The sonophotocatalytic activity of TiO2-NiO photocatalysts with different NiO loading was also evaluated and 10wt% NiO loading was found to be optimal. Moreover, 66% of Total Organic Carbon (TOC) removal was achieved with the optimized TiO2-NiO composite in 140min. In addition, the TiO2-NiO composite exhibited an enhanced photocurrent response under visible light illumination.

  5. In situ and operando atomic force microscopy of high-capacity nano-silicon based electrodes for lithium-ion batteries

    Science.gov (United States)

    Breitung, Ben; Baumann, Peter; Sommer, Heino; Janek, Jürgen; Brezesinski, Torsten

    2016-07-01

    Silicon is a promising next-generation anode material for high-energy-density lithium-ion batteries. While the alloying of nano- and micron size silicon with lithium is relatively well understood, the knowledge of mechanical degradation and structural rearrangements in practical silicon-based electrodes during operation is limited. Here, we demonstrate, for the first time, in situ and operando atomic force microscopy (AFM) of nano-silicon anodes containing polymer binder and carbon black additive. With the help of this technique, the surface topography is analyzed while electrochemical reactions are occurring. In particular, changes in particle size as well as electrode structure and height are visualized with high resolution. Furthermore, the formation and evolution of the solid-electrolyte interphase (SEI) can be followed and its thickness determined by phase imaging and nano-indentation, respectively. Major changes occur in the first lithiation cycle at potentials below 0.6 V with respect to Li/Li+ due to increased SEI formation - which is a dynamic process - and alloying reactions. Overall, these results provide insight into the function of silicon-based composite electrodes and further show that AFM is a powerful technique that can be applied to important battery materials, without restriction to thin film geometries.Silicon is a promising next-generation anode material for high-energy-density lithium-ion batteries. While the alloying of nano- and micron size silicon with lithium is relatively well understood, the knowledge of mechanical degradation and structural rearrangements in practical silicon-based electrodes during operation is limited. Here, we demonstrate, for the first time, in situ and operando atomic force microscopy (AFM) of nano-silicon anodes containing polymer binder and carbon black additive. With the help of this technique, the surface topography is analyzed while electrochemical reactions are occurring. In particular, changes in particle

  6. Research and technological development on heat pumps in Mexico operating with geothermal energy; Investigacion y desarrollo tecnologico sobre bombas de calor en Mexico operando con energia geotermica

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Gutierrez, Alfonso; Barragan Reyes, Rosa Maria; Arellano Gomez, Victor Manuel [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2008-07-01

    The Instituto de Investigaciones Electricas (IIE) and the Comision Federal de Electricidad (CFE) carried out in the past an extensive work of research and development (R&D) on heat pumps (HP). The systems tried on include heat pumps by mechanical compression, thermal absorption and thermal transformers. This paper briefly describes the main aspects of R&D on heat pumps and presents a more detailed description of three of the main studies: a) a Heat Pump (HP) by mechanical compression water-water type, designed for brine purification, operating with low pressure geothermal steam at the geothermal field Los Azufres, Michoacan, Mexico; b) a HP by absorption for cooling and refrigeration, operating with ammoniac/water and low enthalpy geothermal energy, which was tested in the geothermal fields of Los Azufres, Michoacan and Cerro Prieto, Baja California, and c) a thermal transformer by absorption, named Heat Pump by Absorption Type 2, which was tested to evaluate the behavior of diverse ternary solutions as working fluids. To date, there are plans to install and test a geothermal heat pump (connected to the subsoil), in Cerro Prieto, Mexicali, Baja California, Mexico. [Spanish] El Instituto de Investigaciones Electricas (IIE) y la Comision Federal de Electricidad (CFE) realizaron un trabajo extenso de investigacion y desarrollo (I&D) sobre bombas de calor (BC) en el pasado. Los sistemas que se probaron incluyen bombas de calor por compresion mecanica, absorcion y transformadores termicos. Este trabajo describe brevemente los principales aspectos de I&D sobre bombas de calor y se da una descripcion mas detallada de tres de los principales estudios: a) una Bomba de Calor (BC) por compresion mecanica tipo agua-agua, disenada para purificacion de salmueras, operando con vapor geotermico de baja presion en el campo geotermico de Los Azufres, Michoacan; b) una BC por absorcion para enfriamiento y refrigeracion, operando con amoniaco/agua y energia geotermica de baja entalpia

  7. Research on heat pumps in Mexico operating with geothermal energy and waste heat; Investigacion sobre bombas de calor en Mexico operando con energia geotermica y calor de desecho

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Gutierrez, A; Barragan-Reyes, R.M; Arellano-Gomez, V [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)]. E-mail: aggarcia@iie.org.mx

    2008-01-15

    The Instituto de Investigaciones Electricas and the Comision Federal de Electricidad have done research and development (R&D) on heat pumps (HP) in past years. Tested systems include mechanical compression, absorption and heat-transformers. The main R&D aspects on HP are briefly described, and also a more detailed description about three of the main studies is presented: (a) a mechanical compression HP of the water-water type operated with low-pressure geothermal steam at the Los Azufres; Mich., geothermal field, and designed for purification of brine; (b) an absorption HP for cooling and refrigeration operating with ammonia-water and low-enthalpy geothermal energy, which was tested in the Los Azufres and Cerro Prieto, BC, geothermal fields; and (c) a heat-transformer by absorption-Absorption Heat Pump Type II-tested to assess the performance of several ternary solutions as work fluids. Plans exist to install and test a geothermal heat pump at Cerro Prieto or Mexicali, BC. [Spanish] El Instituto de Investigaciones Electricas y la Comision Federal de Electricidad han realizado trabajo de investigacion y desarrollo (I&D) sobre bombas de calor (BC) en el pasado. Los sistemas probados incluyen compresion mecanica, absorcion y transformadores termicos. Este trabajo describe brevemente los principales aspectos de I&D sobre bombas de calor en forma general, y se da una descripcion mas detallada de tres de los principales estudios: (a) una BC por compresion mecanica tipo agua-agua disenada para purificacion de salmueras operando con vapor geotermico de baja presion en el campo geotermico de Los Azufres, Mich.; (b) una BC por absorcion para enfriamiento y refrigeracion operando con amoniaco-agua y energia geotermica de baja entalpia, la cual fue probada en los campos geotermicos de Los Azufres y Cerro Prieto, BC; y (c) un transformador termico por absorcion -llamado Bomba de Calor por Absorcion Tipo II--, el cual fue probado para evaluar el comportamiento de diversas

  8. 基于Nios Ⅱ的多功能数码相框%The digital photo frame based on Nios

    Institute of Scientific and Technical Information of China (English)

    张玲; 高湛; 林英撑; 何伟

    2012-01-01

    The multifunction digital photo frame introduced in this paper is based on the technique'of Nios II. The system, based on Nios II CPU,the SoPC system with reconfigurability and high flexibility has been customized by taking advantages of the soft-core features of Nios II CPU and custom modules. Custom modules have been designed for display controlling, JPEG decoder with pipeline have been designed for higher decoding efficiency, and the SD card controller based on SD protocol has been designed for supporting SD cards. FAT16 file system has been achieved for file managing and convenience to change data with other platforms. μC/OS -II operating system has been embedded for simplifying system software design and improving stability of the system. A multifunction digital photo frame with function of audio playing, and displaying, zooming, rotating and switching effects of photos has been achieved.%介绍了基于Nios Ⅱ的多功能数码相框的实现.系统基于Nios Ⅱ处理器,设计用户自定义模块,构建了灵活性高、可重配置的SoPC系统.设计自定义模块控制LCM显示;采用流水线方式设计JPEG解码自定义模块以提高解码效率;根据SD协议设计SD卡控制器扩展SD卡.实现了FAT16文件系统,便于对SD卡进行文件管理及多平台上的数据交换,并使用μC/OS-Ⅱ操作系统简化软件设计复杂度、提高系统稳定性.最终实现可播放音频并能显示、缩放、旋转图像且带有图像切换特效的多功能数码相框.

  9. 基于Nios-II的FPGA系统设计与研究%FPGA System Design and Research Based on Nios-II

    Institute of Scientific and Technical Information of China (English)

    孙以环

    2015-01-01

    FPGA embedded Nios-II soft core is developed on the basis of traditional hardcore, which has the characteristics of low costs, high flexibility, short production cycle etc and are widely used in the intelligent electronic products, medical devices, wireless communication industry. This paper studies the performance and application of FPGA based soft core embedded Nios-II by focusing on the design of hardware and software. The main work of software design includes soft core design and driver writing soft core design which is designed in Quartus-II software development tools in the SOPC. Finally, soft-core technology embedded FPGA can customize the required peripheral interfaces according to the actual needs flexibly. By introducing emulator debug mode, you can query register and variable on real-time which changes the past inconvenient situation only to debug FPGA simulation and test port. By verifying the design, it can meet the precision of ADC sampling error, the precision of PWM duty ratio, the speed of interrupt response and conduct normal communications.%FPGA内嵌Nios-II软核具有成本低、灵活性高、生产周期短等特点,广泛应用于智能电子产品、医疗电子设备、无线通信产业中。本文主要研究了基于FPGA内嵌Nios-II软核的性能及其应用,重点进行硬件和软件的设计,其中软核设计是通过Quartus-II软件里的SOPC-builder开发工具进行设计;最后FPGA内嵌Nios-II软核可以根据实际需求定制所需要的外设接口,灵活可变。调试方式引入了仿真器,可以进行寄存器、变量实时查询,改变以往FPGA只能通过仿真和测试端口进行调试的不便局面。本次设计通过验证满足ADC采样误差精度、PWM占空比精度、中断响应速度等设计要求,并能够进行正常的通信。

  10. Magnetic dichroism and spin structure of antiferromagnetic NiO(001) films

    NARCIS (Netherlands)

    Altieri, S; Finazzi, M; Hsieh, HH; Lin, HJ; Chen, CT; Hibma, T; Valeri, S; Sawatzky, GA

    2003-01-01

    We find that Ni L-2 edge x-ray magnetic linear dichroism is fully reversed for NiO(001) films on materials with reversed lattice mismatch. We relate this phenomenon to a preferential stabilization of magnetic S domains with main spin component either in or out of the plane, via dipolar interactions.

  11. The magnetic properties of antiferromagnetic nanoparticles: NiO and -Fe2O3

    DEFF Research Database (Denmark)

    Bahl, Christian Robert Haffenden

    2006-01-01

    Nikkel oxid (NiO) og hematit -Fe2O3) er begge antiferromagneter med magnetiske egenskaber på nanoskala, som er forskellige fra dem i større krystaller. Med hovedvægt på nanopartikler af NiO og sammenligninger med nanopartikler af hematit studeres disse magnetiske egenskaber med en række...... egenskaber. Nanopartiklerne af NiO vises at være pladeformede med (111) planer som flader, en tykkelse på omkring 2.3 nm og en diameter på omkring 13 nm. Den magnetiske struktur er magen til den i større krystaller, med spinene holdt i (111) planerne. Målinger af spindynamikken afslører en værdi af den...... morter med hånden. Nanopartikler af antiferromagnetiske materialer vil have et ukompenseret magnetisk moment, der opstår ved endelige partikelstørrelser på grund af overskydende spin på det ene undergitter. Dette ukompenserede moment kvantiseres i NiO nanopartiklerne og findes at være uafhængigt af...

  12. Spatially resolved resistance of NiO nanostructures under humid environment

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, Christopher B [ORNL; Ievlev, Anton [ORNL; Collins, Liam F [ORNL; Muckley, Eric S [ORNL; Joshi, Pooran C [ORNL; Ivanov, Ilia N [ORNL

    2016-01-01

    The spatially resolved electrical response of polycrystalline NiO films composed of 40 nm crystallites was investigated under different relative humidity levels (RH). The topological and electrical properties (surface potential and resistance) were characterized with sub 25nm resolution using Kelvin probe force microscopy (KPFM) and conductive scanning probe microscopy under argon atmosphere at 0%, 50%, and 80% relative humidity. The dimensionality of surface features obtained through autocorrelation analysis of topological maps increased linearly with increased relative humidity, as water was adsorbed onto the film surface. Surface potential decreased from about 280mV to about 100 mV and resistance decreased from about 5 G to about 3 G , in a nonlinear fashion when relative humidity was increased from 0% to 80%. Spatially resolved surface potential and resistance of the NiO films was found to be heterogeneous throughout the film, with distinct domains that grew in size from about 60 nm to 175 nm at 0% and 80% RH levels, respectively. The heterogeneous character of the topological, surface potential, and resistance properties of the polycrystalline NiO film observed under dry conditions decreased with increased relative humidity, yielding nearly homogeneous surface properties at 80% RH, suggesting that the nanoscale potential and resistance properties converge with the mesoscale properties as water is adsorbed onto the NiO film.

  13. Heritage of humanity, culture and place Patrimônio da Humanidade, cultura e lugar

    Directory of Open Access Journals (Sweden)

    Wagner Costa Ribeiro

    2010-05-01

    Full Text Available Discussing the concept of heritage and its implications is the objective of this paper. It deals with international definitions, recovers the proposal of the Hague Convention and the Convention Concerning the Protection of the World Cultural and Natural Heritage of Unesco. Then, it approaches the concepts of culture and place. It also focuses on definitions of natural and cultural heritage, as well as the systems of heritage management.Discutir o conceito de patrimônio e suas implicações é o objetivo deste trabalho. Ele trata as definições internacionais, retoma a proposta da Convenção de Haia e a da Convenção de Patrimônio Mundial da Unesco. Depois, problematiza os conceitos de cultura e de lugar. Também são abordadas as definições de patrimônio cultural e natural, bem como os sistemas de gestão do patrimônio.

  14. Long-term (30 days toxicity of NiO nanoparticles for adult zebrafish Danio rerio

    Directory of Open Access Journals (Sweden)

    Kovrižnych Jevgenij A.

    2014-03-01

    Full Text Available Nickel oxide in the form of nanoparticles (NiO NPs is extensively used in different industrial branches. In a test on adult zebrafish, the acute toxicity of NiO NPs was shown to be low, however longlasting contact with this compound can lead to its accumulation in the tissues and to increased toxicity. In this work we determined the 30-day toxicity of NiO NPs using a static test for zebrafish Danio rerio. We found the 30-day LC50 value to be 45.0 mg/L, LC100 (minimum concentration causing 100% mortality was 100.0 mg/L, and LC0 (maximum concentration causing no mortality was 6.25 mg/L for adult individuals of zebrafish. Considering a broad use of Ni in the industry, NiO NPs chronic toxicity may have a negative impact on the population of aquatic organisms and on food web dynamics in aquatic systems.

  15. Facile Route to NiO Nanostructured Electrode Grown by Oblique Angle Deposition Technique for Supercapacitors.

    Science.gov (United States)

    Kannan, Vasudevan; Inamdar, Akbar I; Pawar, Sambaji M; Kim, Hyun-Seok; Park, Hyun-Chang; Kim, Hyungsang; Im, Hyunsik; Chae, Yeon Sik

    2016-07-13

    We report an efficient method for growing NiO nanostructures by oblique angle deposition (OAD) technique in an e-beam evaporator for supercapacitor applications. This facile physical vapor deposition technique combined with OAD presents a unique, direct, and economical route for obtaining high width-to-height ratio nanorods for supercapacitor electrodes. The NiO nanostructure essentially consists of nanorods with varying dimensions. The sample deposited at OAD 75° showed highest supercapacitance value of 344 F/g. NiO nanorod electrodes exhibits excellent electrochemical stability with no degradation in capacitance after 5000 charge-discharge cycles. The nanostructured film adhered well to the substrate and had 131% capacity retention. Peak energy density and power density of the NiO nanorods were 8.78 Wh/kg and 2.5 kW/kg, respectively. This technique has potential to be expanded for growing nanostructured films of other interesting metal/metal oxide candidates for supercapacitor applications.

  16. Magnetostructural phase transitions in NiO and MnO: Neutron diffraction data

    Science.gov (United States)

    Balagurov, A. M.; Bobrikov, I. A.; Sumnikov, S. V.; Yushankhai, V. Yu.; Mironova-Ulmane, N.

    2016-07-01

    Structural and magnetic phase transitions in NiO and MnO antiferromagnets have been studied by high-precision neutron diffraction. The experiments have been performed on a high-resolution Fourier diffractometer (pulsed reactor IBR-2), which has the record resolution for the interplanar distance and a high intensity in the region of large interplanar distances; as a result, the characteristics of both transitions have been determined simultaneously. It has been shown that the structural and magnetic transitions in MnO occur synchronously and their temperatures coincide within the experimental errors: T str ≈ T mag ≈ (119 ± 1) K. The measurements for NiO have been performed with powders with different average sizes of crystallites (~1500 nm and ~138 nm). It has been found that the transition temperatures differ by ~50 K: T str = (471 ± 3) K, T mag = (523 ± 2) K. It has been argued that a unified mechanism of the "unsplit" magnetic and structural phase transition at a temperature of T mag is implemented in MnO and NiO. Deviation from this scenario in the behavior of NiO is explained by the quantitative difference—a weak coupling between the magnetic and secondary structural order parameters.

  17. A Novel Method for Making NiO Nanofibres via An Electrospinning Technique

    Institute of Scientific and Technical Information of China (English)

    Chang Lu SHAO; Hong Yu GUAN; Shang Bin WEN; Bin CHEN; Xing Hua YANG; Jian GONG

    2004-01-01

    Thin PVA/nickel acetate composite fibres were prepared by using sol-gel processing and electrospinning technique. After calcination of the above precursor fibres, NiO nanofibres with a diameter of 50-150 nm could be successfully obtained. The fibres were characterized by SEM, FT-IR, WAXD, respectively.

  18. Magnetic properties of NiO (nickel oxide) nanoparticles : Blocking temperature and Neel temperature

    NARCIS (Netherlands)

    Tadic, Marin; Nikolic, Dobrica; Panjan, Matjaz; Blake, Graeme R.

    2015-01-01

    Crystalline nickel oxide (NiO) nanoparticles dispersed in an amorphous silica matrix have been prepared by a sol-gel combustion synthesis method. The sample was characterized using X-ray powder diffraction, energy-dispersive X-ray spectroscopy, scanning electron microscopy, transmission electron mic

  19. Structural, Optical and Electrical Properties of NiO Nanostructure Thin Film

    Directory of Open Access Journals (Sweden)

    M. Ghougali

    2016-12-01

    Full Text Available Nickel oxide was deposited on highly cleaned glass substrates using spray pneumatic technique. The effect of precursor molarity on structural, optical and electrical properties has been studied. The XRD lines of the deposited NiO were enhanced with increasing precursor molarity due to the improvement of the films crystallinity. It was shown that the crystalline size of the deposited thin films was calculated using Debye-Scherer formula and found in the range between 9 and 47 nm. The optical properties have been discussed in this work. The absorbance (A, the transmittance (T and the reflectance (R were measured and calculated. Band gap energy is considered one of the most important optical parameter, therefore measured and found ranging between 3.64 and 3.86 eV. The NiO thin film reduces the light reflection for visible range light. The increase of the electrical conductivity to maximum value of 0.0896 (Ω cm – 1 can be explained by the increase in carrier concentration of the films. A good electrical conductivity of the NiO thin film is obtained due to the electrically low sheet resistance. NiO can be applied in different electronic and optoelectronic applications due to its high band gap, high transparency and good electrical conductivity.

  20. Installation and operation manual on sea level gauge (Model: NIO_Ghana_2004)

    Digital Repository Service at National Institute of Oceanography (India)

    Joseph, A; Pereira, A; VijayKumar, K.; Prabhudesai, S.; Methar, A; Dias, M.

    NIO sea level gauge is a pressure-based gauge that operates on 12 volts battery. The pressure-sensing element used in this gauge is a piezo-resistive programmable semiconductor transducer that provides pressure samples in RS-485 format...