The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
Trygve Eidet - One of the best experts on this subject based on the ideXlab platform.
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an impedance study of the kinetics and mechanism of the Anodic Reaction on graphite anodes in saturated cryolite alumina melts
Journal of The Electrochemical Society, 1996Co-Authors: A. Kisza, Jomar Thonstad, Trygve EidetAbstract:The Anodic Reaction on spectrally pure graphite (SPG) and pyrolytic graphite was studied in the potential range from 1.2 to 1.8 V vs. an aluminium reference electrode in alumina-saturated cryolite melts at 1000°C by means of electrochemical impedance spectroscopy. It has been found that the total electrode Reaction can be interpreted by a two-step two-electron charge-transfer process with an intermediate adsorption. The experimentally recorded impedance spectra were interpreted in terms of an equivalent circuit approach and the kinetic theory of Bai and Conway, giving the double-layer capacitance, electrode coverage, effective rate constants, and the charge needed for the coverage of the electrode by a monolayer. The process is faster on SPG anode, and on both anodes the second step is faster than the first one.
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An Impedance Study of the Kinetics and Mechanism of the Anodic Reaction on Graphite Anodes in Saturated Cryolite‐Alumina Melts
Journal of The Electrochemical Society, 1996Co-Authors: A. Kisza, Jomar Thonstad, Trygve EidetAbstract:The Anodic Reaction on spectrally pure graphite (SPG) and pyrolytic graphite was studied in the potential range from 1.2 to 1.8 V vs. an aluminium reference electrode in alumina-saturated cryolite melts at 1000°C by means of electrochemical impedance spectroscopy. It has been found that the total electrode Reaction can be interpreted by a two-step two-electron charge-transfer process with an intermediate adsorption. The experimentally recorded impedance spectra were interpreted in terms of an equivalent circuit approach and the kinetic theory of Bai and Conway, giving the double-layer capacitance, electrode coverage, effective rate constants, and the charge needed for the coverage of the electrode by a monolayer. The process is faster on SPG anode, and on both anodes the second step is faster than the first one.
A. Kisza - One of the best experts on this subject based on the ideXlab platform.
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Mechanism and kinetics of the Anodic Reaction in cryolite melts. II. The influence of AIF 3 (11 wt%) at different Al2O3 content
Polish Journal of Chemistry, 2020Co-Authors: A. Kisza, Jomar Thonstad, J. HivesAbstract:Aluminium trifluoride is the main additive to the cryolite-based electrolyte in aluminium electrolysis. By Electrochemical Impedance Spectroscopy (EIS) the influence of AlF3 upon the kinetics and mechanism of the Anodic Reaction in 4 cryolite–alumina melts containing 2, 4, 6 and 8 wt% of alumina and 11 wt% of AlF3 was determined at 1000C. The addition of 11 wt% of AlF3 to a cryolite melt with a certain alumina content increases the overpotential of the Anodic Reaction as compared to cryolite-alumina saturated (CRAS) melt. The Tafel slope increases from around 0.12 V/dec. to 0.24 V/dec., which indicates that at low alumina content the second charge transfer step is the rds, whereas at higher alumina content this control is shifted towards the first step. The effective rate constants of both charge transfer steps are increasing with the alumina content. It can be concluded that the influence of the added AlF3 is directly related to the participation of this reagent in the first charge transfer step, in which it is a product. The diffusion coefficient of the Al2OF 6 2 anionic species decreases as a function of the alumina content, due to the increase of the viscosity of the melts studied.
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an impedance study of the kinetics and mechanism of the Anodic Reaction on graphite anodes in saturated cryolite alumina melts
Journal of The Electrochemical Society, 1996Co-Authors: A. Kisza, Jomar Thonstad, Trygve EidetAbstract:The Anodic Reaction on spectrally pure graphite (SPG) and pyrolytic graphite was studied in the potential range from 1.2 to 1.8 V vs. an aluminium reference electrode in alumina-saturated cryolite melts at 1000°C by means of electrochemical impedance spectroscopy. It has been found that the total electrode Reaction can be interpreted by a two-step two-electron charge-transfer process with an intermediate adsorption. The experimentally recorded impedance spectra were interpreted in terms of an equivalent circuit approach and the kinetic theory of Bai and Conway, giving the double-layer capacitance, electrode coverage, effective rate constants, and the charge needed for the coverage of the electrode by a monolayer. The process is faster on SPG anode, and on both anodes the second step is faster than the first one.
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An Impedance Study of the Kinetics and Mechanism of the Anodic Reaction on Graphite Anodes in Saturated Cryolite‐Alumina Melts
Journal of The Electrochemical Society, 1996Co-Authors: A. Kisza, Jomar Thonstad, Trygve EidetAbstract:The Anodic Reaction on spectrally pure graphite (SPG) and pyrolytic graphite was studied in the potential range from 1.2 to 1.8 V vs. an aluminium reference electrode in alumina-saturated cryolite melts at 1000°C by means of electrochemical impedance spectroscopy. It has been found that the total electrode Reaction can be interpreted by a two-step two-electron charge-transfer process with an intermediate adsorption. The experimentally recorded impedance spectra were interpreted in terms of an equivalent circuit approach and the kinetic theory of Bai and Conway, giving the double-layer capacitance, electrode coverage, effective rate constants, and the charge needed for the coverage of the electrode by a monolayer. The process is faster on SPG anode, and on both anodes the second step is faster than the first one.
Hiromichi Arai - One of the best experts on this subject based on the ideXlab platform.
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effects of anode material and fuel on Anodic Reaction of solid oxide fuel cells
Journal of The Electrochemical Society, 1992Co-Authors: Toshihiko Setoguchi, Kotaro Okamoto, Koichi Eguchi, Hiromichi AraiAbstract:In this paper, Anodic properties of solid oxide fuel cells are evaluated for several anode/electrolyte systems. Anodic over-voltage of metal/yttria-stabilized zirconia (YSZ) interface was related with metal-oxygen bonding strength and was the smallest for the Ni anode in the present study. The Anodic polarization conductivity of Ni-YSZ cermet/YSZ electrolyte interface strongly depended on oxygen partial pressure P[sub 02], in fuel, but was independent of the kind of fuel (H[sub 2]-H[sub 2]O, CO-CO[sub 2] and CH[sub 4]-H[sub 2]O). The activation of oxygen ion appears to be the rate limiting step in the overall Reaction. The overvoltages of Ni/ and Pt/samaria-doped ceria (SDC) were very small as compared with those of Ni/ and Pt/YSZ. The Anodic properties were also influenced by the oxide material mixed with Ni as a cermet component.
Mitsuru Sano - One of the best experts on this subject based on the ideXlab platform.
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Ru-catalyzed anode materials for direct hydrocarbon SOFCs
Electrochimica Acta, 2003Co-Authors: Takashi Hibino, Atsuko Hashimoto, Masaya Yano, Masanori Suzuki, Mitsuru SanoAbstract:Abstract A solid oxide fuel cell using a thin ceria-based electrolyte film with a Ru-catalyzed anode was directly operated on hydrocarbons, including methane, ethane, and propane, at 600 °C. The role of the Ru catalyst in the anode Reaction was to promote the reforming Reaction of the unreacted hydrocarbons by the produced steam and CO 2 , which avoided interference from steam and CO 2 in the gas-phase diffusion of the fuels. The resulting peak power density reached 750 mW cm −2 with dry methane, which was comparable to the peak power density of 769 mW cm −2 with wet (2.9 vol.% H 2 O) hydrogen. More important was the fact that the cell performance was maintained at a high level regardless of the change in the methane utilization from 12 to 46% but was significantly reduced by increasing the hydrogen utilization from 13 to 42%. While the Anodic Reaction of hydrogen was controlled by the slow gas diffusion, the Anodic Reaction of methane was not subject to the onset of such a gas-diffusion process.
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A Fuel-Cell-Type Sensor for Detection of Carbon Monoxide in Reformed Gases
Electrochemical and Solid State Letters, 2002Co-Authors: Atsuko Hashimoto, Takashi Hibino, Mitsuru SanoAbstract:A solid oxide fuel cell using a samaria-doped ceria electrolyte with a Pd anode was fabricated for detecting carbon monoxide (CO) in reformed gases at 300°C. The CO concentration in a flowing mixture of 0-4000 ppm CO, 50%hydrogen, 10% carbon dioxide, and 6% water vapor was related to a decrease in both the electromotive force generated from the cell and the short-circuit current through the cell due to a reversible change in the Anodic Reaction resistance with the CO concentration. In both signals, the minimum detectable concentration was 50 ppm, and the 90% response and 90% recovery times were as short as 20 s.
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an intermediate temperature solid oxide fuel cell providing higher performance with hydrocarbons than with hydrogen
Electrochemical and Solid State Letters, 2002Co-Authors: Takashi Hibino, Atsuko Hashimoto, Masaya Yano, Masanori Suzuki, Kazuyo Asano, Mitsuru SanoAbstract:The promotion of direct electrochemical oxidation of hydrocarbons in a solid oxide fuel cell was investigated using a ceria-based electrolyte with different noble metals-containing anode at 600°C. The objective was to avoid interference from a large amount of steam and CO 2 being produced by discharging the cell, because these gases degrade the anode performance, especially at a high fuel utilization. Ru was an effective catalyst for removing these gases from the anode surface due to its high catalytic activity for the steam and CO 2 reforming of hydrocarbons. The resulting peak power densities reached 750 mW cm - 2 with dry methane, which was comparable to the peak power density of 769 mW cm - 2 with wet (2.9 vol %H 2 O) hydrogen. The cell performance was maintained at a high level regardless of the change in methane utilization from 12 to 46% but was significantly reduced by increasing hydrogen utilization from 13 to 42%. The Anodic Reaction of hydrogen was controlled by the slow surface diffusion of hydrogen, while the Anodic Reaction of methane was not subject to the onset of such a gas-diffusion process.
Jomar Thonstad - One of the best experts on this subject based on the ideXlab platform.
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Mechanism and kinetics of the Anodic Reaction in cryolite melts. II. The influence of AIF 3 (11 wt%) at different Al2O3 content
Polish Journal of Chemistry, 2020Co-Authors: A. Kisza, Jomar Thonstad, J. HivesAbstract:Aluminium trifluoride is the main additive to the cryolite-based electrolyte in aluminium electrolysis. By Electrochemical Impedance Spectroscopy (EIS) the influence of AlF3 upon the kinetics and mechanism of the Anodic Reaction in 4 cryolite–alumina melts containing 2, 4, 6 and 8 wt% of alumina and 11 wt% of AlF3 was determined at 1000C. The addition of 11 wt% of AlF3 to a cryolite melt with a certain alumina content increases the overpotential of the Anodic Reaction as compared to cryolite-alumina saturated (CRAS) melt. The Tafel slope increases from around 0.12 V/dec. to 0.24 V/dec., which indicates that at low alumina content the second charge transfer step is the rds, whereas at higher alumina content this control is shifted towards the first step. The effective rate constants of both charge transfer steps are increasing with the alumina content. It can be concluded that the influence of the added AlF3 is directly related to the participation of this reagent in the first charge transfer step, in which it is a product. The diffusion coefficient of the Al2OF 6 2 anionic species decreases as a function of the alumina content, due to the increase of the viscosity of the melts studied.
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an impedance study of the kinetics and mechanism of the Anodic Reaction on graphite anodes in saturated cryolite alumina melts
Journal of The Electrochemical Society, 1996Co-Authors: A. Kisza, Jomar Thonstad, Trygve EidetAbstract:The Anodic Reaction on spectrally pure graphite (SPG) and pyrolytic graphite was studied in the potential range from 1.2 to 1.8 V vs. an aluminium reference electrode in alumina-saturated cryolite melts at 1000°C by means of electrochemical impedance spectroscopy. It has been found that the total electrode Reaction can be interpreted by a two-step two-electron charge-transfer process with an intermediate adsorption. The experimentally recorded impedance spectra were interpreted in terms of an equivalent circuit approach and the kinetic theory of Bai and Conway, giving the double-layer capacitance, electrode coverage, effective rate constants, and the charge needed for the coverage of the electrode by a monolayer. The process is faster on SPG anode, and on both anodes the second step is faster than the first one.
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An Impedance Study of the Kinetics and Mechanism of the Anodic Reaction on Graphite Anodes in Saturated Cryolite‐Alumina Melts
Journal of The Electrochemical Society, 1996Co-Authors: A. Kisza, Jomar Thonstad, Trygve EidetAbstract:The Anodic Reaction on spectrally pure graphite (SPG) and pyrolytic graphite was studied in the potential range from 1.2 to 1.8 V vs. an aluminium reference electrode in alumina-saturated cryolite melts at 1000°C by means of electrochemical impedance spectroscopy. It has been found that the total electrode Reaction can be interpreted by a two-step two-electron charge-transfer process with an intermediate adsorption. The experimentally recorded impedance spectra were interpreted in terms of an equivalent circuit approach and the kinetic theory of Bai and Conway, giving the double-layer capacitance, electrode coverage, effective rate constants, and the charge needed for the coverage of the electrode by a monolayer. The process is faster on SPG anode, and on both anodes the second step is faster than the first one.
