Cu-Ni Cermet Anodes for Direct Oxidation of Methane in Solid-Oxide Fuel Cells

Kim, H.; Lu, Chun; Worrell, W. L.; Vohs, John M.; Gorte, Raymond J.

doi:10.1149/1.1445170

Cited by 349 publications

(264 citation statements)

References 14 publications

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“…Fig. 3, which shows a picture of a Ni-YSZ cermet after heating in H 2 at 800ºC, after heating in 100% CH 4 at 800ºC for 1.5 hrs, and after heating in 40% toluene at 700ºC for 1.5 hrs [28,29]. The amount of carbon formed on the Ni cermet by exposure to CH 4 and toluene are clearly unacceptable.…”

Section: Stability Towards Carbon Formationmentioning

confidence: 99%

Novel SOFC anodes for the direct electrochemical oxidation of hydrocarbons

Gorte

Vohs

2003

Journal of Catalysis

274

157

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Recent developments in solid-oxide fuel cells (SOFC) that electrochemically oxidize hydrocarbon fuels to produce electrical power without first reforming them to H 2 are described. First, the operating principles of SOFCs are reviewed, along with a description of state-of-the-art SOFC designs. This is followed by a discussion of the concepts and procedures used in the synthesis of direct-oxidation fuel cells with anodes based on composites of Cu, ceria, and yttria-stabilized zirconia. The discussion focuses on how heterogeneous catalysis has an important role to play in the development of SOFCs that directly oxidize hydrocarbon fuels. AbstractRecent developments in solid-oxide fuel cells (SOFC) that electrochemically oxidize hydrocarbon fuels to produce electrical power without first reforming them to H 2 are described.First, the operating principles of SOFCs are reviewed, along with a description of state-of-the-art SOFC designs. This is followed by a discussion of the concepts and procedures used in the synthesis of direct-oxidation fuel cells with anodes based on composites of Cu, ceria, and yttriastabilized zirconia. The discussion focuses on how heterogeneous catalysis has an important role to play in the development of SOFCs that directly oxidize hydrocarbon fuels.

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Section: Stability Towards Carbon Formationmentioning

confidence: 99%

Novel SOFC anodes for the direct electrochemical oxidation of hydrocarbons

Gorte

Vohs

2003

Journal of Catalysis

274

157

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“…We believe that our main contribution to this goal has been the development of a synthesis method that is very flexible in allowing the electrodes to be prepared at low temperatures. Low-temperature synthesis allows the use of many materials that would not otherwise be compatible with standard ceramic-fabrication methods, including the addition of catalytic materials, the controlled fabrication of alloys [30], etc. We expect that this capability will result in improved SOFC for the future.…”

Section: Future Directionsmentioning

confidence: 99%

Recent developments on anodes for direct fuel utilization in SOFC

Gorte

2004

Solid State Ionics

122

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This paper reviews recent work on SOFC anode fabrication at the University of Pennsylvania. In this work, anode fabrication is based on the preparation of a porous YSZ matrix, into which electronic and catalytic components are added by impregnation of the appropriate metal salts. First, the methods used to prepare porous YSZ are described, along with a description of the structures that are obtained. Next, it is demonstrated that cell performance is strongly affected by the methods used to impregnate and pretreat ceria that is added to the porous YSZ. Third, the role of carbonaceous deposits within the anode is discussed. These deposits can lead to improved electronic conductivity that results in improved performance. Finally, the effect of precious-metal dopants, added to ceria to improve the catalytic properties of the anode, is discussed. Pd, Pt, and Rh are shown to give large increases in the performance of the cells, particularly in CH 4 . KeywordsSolid-oxide fuel cell, Direct utilization, n-Butane, Methane, Cu, Yttria-stabilized zirconia, Ceria AbstractThis paper reviews recent work on SOFC anode fabrication at the University of Pennsylvania. In this work, anode fabrication is based on the preparation of a porous YSZ matrix, into which electronic and catalytic components are added by impregnation of the appropriate metal salts. First, the methods used to prepare porous YSZ are described, along with a description of the structures that are obtained. Next, it is demonstrated that cell performance is strongly affected by the methods used to impregnate and pretreat ceria that is added to the porous YSZ. Third, the role of carbonaceous deposits within the anode is discussed. These deposits can lead to improved electronic conductivity that results in improved performance. Finally, the effect of precious-metal dopants, added to ceria to improve the catalytic properties of the anode, is discussed. Pd, Pt, and Rh are shown to give large increases in the performance of the cells, particularly in CH 4 .

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“…Small amounts of carbon deposits may connect some isolated Ni particles, converting them to active sites for electrochemical reactions and allowing the produced electron to transport to the external circuit [42]. Figure 3 shows V-I curves and Nyquist plots of impedance spectra for the LSCF-Ni/YSZ anode fuel cell in He/H 2 (100 sccm, 50 vol% H 2 ) after 16 h of reduction and in He/CH 4 (25 vol% CH 4 ) after 3 h of switching fuels.…”

Section: Resultsmentioning

confidence: 99%

“…Maximum power density decreased to 22% of its initial value after 38 h. The slopes of the V-I curves at low current densities were decreased after 9 h of operation in CH 4 , matching with the lower polarization resistances in the corresponding impedance spectra. The decrease in polarization resistance can be explained by deposition of moderate levels of carbon on the anode, which may connect isolated metal particles and convert them to active sites for electrochemical reactions [42]. A gradual decrease in open circuit voltage (OCV) from theoretical OCV was observed after 2 h. A significant decrease in OCV (from 0.8 to 0.6 V) was accompanied by a decrease in current density, indicating initiation of a crack in the fuel cell after about 13 h. Oxygen leakage into the anode chamber from the crack would cause a decrease in OCV and a significant increase in ohmic resistance of the fuel cell, shown in the corresponding impedance spectra in Figure 5a.…”

Section: Figure 2 V-i Curves Andmentioning

confidence: 99%

La0.6Sr0.4Co0.2Fe0.8O3 Perovskite: A Stable Anode Catalyst for Direct Methane Solid Oxide Fuel Cells

Mirzababaei

Chuang

2014

Catalysts

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Direct methane solid oxide fuel cells, operated by supplying methane to a Ni/YSZ anode, suffer from degradation via accumulation of carbon deposits on the Ni surface. Coating a 40 µm thin film of La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 (LSCF) perovskite on the Ni/YSZ anode surface decreased the amount of carbon deposits, slowing down the degradation rate. The improvement in anode durability could be related to the oxidation activity of LSCF which facilitates oxidation of CH 4 and carbon deposits. Analysis of the crystalline structure of LSCF revealed that LSCF was stable in the reducing anode environment under H 2 and CH 4 flow at 750 °C and retained its perovskite structure throughout the 475 h long-term stability test.

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Cu-Ni Cermet Anodes for Direct Oxidation of Methane in Solid-Oxide Fuel Cells

Cited by 349 publications

References 14 publications

Novel SOFC anodes for the direct electrochemical oxidation of hydrocarbons

Novel SOFC anodes for the direct electrochemical oxidation of hydrocarbons

Recent developments on anodes for direct fuel utilization in SOFC

La0.6Sr0.4Co0.2Fe0.8O3 Perovskite: A Stable Anode Catalyst for Direct Methane Solid Oxide Fuel Cells

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