251
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Li Q, Thangadurai V. A comparative 2 and 4-probe DC and 2-probe AC electrical conductivity of novel co-doped Ce0.9−xRExMo0.1O2.1–0.5x (RE = Y, Sm, Gd; x = 0.2, 0.3). ACTA ACUST UNITED AC 2010. [DOI: 10.1039/c0jm01324b] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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252
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Reddy GK, Thrimurthulu G, Reddy BM. A Rapid Microwave-Induced Solution Combustion Synthesis of Ceria-Based Mixed Oxides for Catalytic Applications. CATALYSIS SURVEYS FROM ASIA 2009. [DOI: 10.1007/s10563-009-9081-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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253
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Kan H, Hyun SH, Shul YG, Lee H. Improved solid oxide fuel cell anodes for the direct utilization of methane using Sn-doped Ni/YSZ catalysts. CATAL COMMUN 2009. [DOI: 10.1016/j.catcom.2009.09.021] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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254
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Yang L, Wang S, Blinn K, Liu M, Liu Z, Cheng Z, Liu M. Enhanced sulfur and coking tolerance of a mixed ion conductor for SOFCs: BaZr(0.1)Ce(0.7)Y(0.2-x)Yb(x)O(3-delta). Science 2009; 326:126-9. [PMID: 19797657 DOI: 10.1126/science.1174811] [Citation(s) in RCA: 224] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The anode materials that have been developed for solid oxide fuel cells (SOFCs) are vulnerable to deactivation by carbon buildup (coking) from hydrocarbon fuels or by sulfur contamination (poisoning). We report on a mixed ion conductor, BaZr(0.1)Ce(0.7)Y(0.2-)(x)Yb(x)O(3-delta), that allows rapid transport of both protons and oxide ion vacancies. It exhibits high ionic conductivity at relatively low temperatures (500 degrees to 700 degrees C). Its ability to resist deactivation by sulfur and coking appears linked to the mixed conductor's enhanced catalytic activity for sulfur oxidation and hydrocarbon cracking and reforming, as well as enhanced water adsorption capability.
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Affiliation(s)
- Lei Yang
- School of Materials Science and Engineering, Center for Innovative Fuel Cell and Battery Technologies, Georgia Institute of Technology, Atlanta, GA 30332, USA
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255
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Abstract
This article presents a brief review on modeling philosophies of solid-oxide fuel cells (SOFCs) including an introduction to SOFC components and their functions. While a plethora of numerical models is available for SOFC modeling and simulation, this paper focuses on a general overview on mathematical model equations that represent the physico-chemical processes occurring in SOFCs and their boundary conditions. Electrochemical model equations, their simplifications, significance, and solution methods are discussed. Charge transfer chemistry is described in detail from a global as well as from elementary charge transfer perspective. Principles of heterogeneous reforming chemistry on conventional nickel cermet anodes, evaluation of rate expressions, and the implementation of the thermo chemistry into SOFC flow models are described. Results of numerical simulations are presented for configurations ranging from complex stacks to simple zero dimensional electrochemical systems.
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256
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General and facile synthesis of ceria-based solid solution nanocrystals and their catalytic properties. J SOLID STATE CHEM 2009. [DOI: 10.1016/j.jssc.2009.07.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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257
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Sadykov V, Mezentseva N, Alikina G, Bunina R, Pelipenko V, Lukashevich A, Tikhov S, Usoltsev V, Vostrikov Z, Bobrenok O, Smirnova A, Ross J, Smorygo O, Rietveld B. Nanocomposite catalysts for internal steam reforming of methane and biofuels in solid oxide fuel cells: Design and performance. Catal Today 2009. [DOI: 10.1016/j.cattod.2009.02.035] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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258
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259
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Zuo YB, Li JH, Zeng Q, Liu W, Chen CS. Estimation of oxygen ionic conductivity in nickel-zirconia composite by oxygen permeation method. J Solid State Electrochem 2009. [DOI: 10.1007/s10008-009-0893-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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260
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Matsuda Y, Karppinen M, Yamazaki Y, Yamauchi H. Oxygen-vacancy concentration in A2MgMoO6−δ double-perovskite oxides. J SOLID STATE CHEM 2009. [DOI: 10.1016/j.jssc.2009.04.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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261
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Direct Utilization of Liquid Fuels in SOFC for Portable Applications: Challenges for the Selection of Alternative Anodes. ENERGIES 2009. [DOI: 10.3390/en20200377] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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262
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263
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264
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Paulus W, Schober H, Eibl S, Johnson M, Berthier T, Hernandez O, Ceretti M, Plazanet M, Conder K, Lamberti C. Lattice dynamics to trigger low temperature oxygen mobility in solid oxide ion conductors. J Am Chem Soc 2009; 130:16080-5. [PMID: 18986139 DOI: 10.1021/ja806144a] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
SrFeO(2.5) and SrCoO(2.5) are able to intercalate oxygen in a reversible topotactic redox reaction already at room temperature to form the cubic perovskites Sr(Fe,Co)O(3), while CaFeO(2.5) can only be oxidized under extreme conditions. To explain this significant difference in low temperature oxygen mobility, we investigated the homologous SrFeO(2.5) and CaFeO(2.5) by temperature dependent oxygen isotope exchange as well as by inelastic neutron scattering (INS) studies, combined with ab initio (DFT) molecular dynamical calculations. From (18)O/(16)O isotope exchange experiments we proved free oxygen mobility to be realized in SrFeO(x) already below 600 K. We have also evidence that low temperature oxygen mobility relies on the existence of specific, low energy lattice modes, which trigger and amplify oxygen mobility in solids. We interpret the INS data together with the DFT-based molecular dynamical simulation results on SrFeO(2.5) and CaFeO(2.5) in terms of an enhanced, phonon-assisted, low temperature oxygen diffusion for SrFeO(3-x) as a result of the strongly reduced Fe-O-Fe bond strength of the apical oxygen atoms in the FeO(6) octahedra along the stacking axis. This dynamically triggered phenomenon leads to an easy migration of the oxide ions into the open vacancy channels and vice versa. The decisive impact of lattice dynamics, giving rise to structural instabilities in oxygen deficient perovskites, especially with brownmillerite-type structure, is demonstrated, opening new concepts for the design and tailoring of low temperature oxygen ion conductors.
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Affiliation(s)
- Werner Paulus
- Sciences Chimiques de Rennes, UMR 6226 CNRS-Université de Rennes1, Inorganic Materials: Soft Chemistry and Reactivity of Solids, Campus de Beaulieu, F-35042 Rennes, France, Institut Laue-Langevin, BP 156 X, F-38042 Grenoble Cedex, France, Department of Inorganic, Physical and Materials Chemistry and NIS Center of Excellence, and INSTM “Centro di Riferimento”, University of Turin, Italy, European Laboratory for Non-Linear Spectroscopy, University of Florence, Polo Scientifico, I-50019 Sesto-Fiorentin,
| | - Helmut Schober
- Sciences Chimiques de Rennes, UMR 6226 CNRS-Université de Rennes1, Inorganic Materials: Soft Chemistry and Reactivity of Solids, Campus de Beaulieu, F-35042 Rennes, France, Institut Laue-Langevin, BP 156 X, F-38042 Grenoble Cedex, France, Department of Inorganic, Physical and Materials Chemistry and NIS Center of Excellence, and INSTM “Centro di Riferimento”, University of Turin, Italy, European Laboratory for Non-Linear Spectroscopy, University of Florence, Polo Scientifico, I-50019 Sesto-Fiorentin,
| | - Stefan Eibl
- Sciences Chimiques de Rennes, UMR 6226 CNRS-Université de Rennes1, Inorganic Materials: Soft Chemistry and Reactivity of Solids, Campus de Beaulieu, F-35042 Rennes, France, Institut Laue-Langevin, BP 156 X, F-38042 Grenoble Cedex, France, Department of Inorganic, Physical and Materials Chemistry and NIS Center of Excellence, and INSTM “Centro di Riferimento”, University of Turin, Italy, European Laboratory for Non-Linear Spectroscopy, University of Florence, Polo Scientifico, I-50019 Sesto-Fiorentin,
| | - Mark Johnson
- Sciences Chimiques de Rennes, UMR 6226 CNRS-Université de Rennes1, Inorganic Materials: Soft Chemistry and Reactivity of Solids, Campus de Beaulieu, F-35042 Rennes, France, Institut Laue-Langevin, BP 156 X, F-38042 Grenoble Cedex, France, Department of Inorganic, Physical and Materials Chemistry and NIS Center of Excellence, and INSTM “Centro di Riferimento”, University of Turin, Italy, European Laboratory for Non-Linear Spectroscopy, University of Florence, Polo Scientifico, I-50019 Sesto-Fiorentin,
| | - Tanguy Berthier
- Sciences Chimiques de Rennes, UMR 6226 CNRS-Université de Rennes1, Inorganic Materials: Soft Chemistry and Reactivity of Solids, Campus de Beaulieu, F-35042 Rennes, France, Institut Laue-Langevin, BP 156 X, F-38042 Grenoble Cedex, France, Department of Inorganic, Physical and Materials Chemistry and NIS Center of Excellence, and INSTM “Centro di Riferimento”, University of Turin, Italy, European Laboratory for Non-Linear Spectroscopy, University of Florence, Polo Scientifico, I-50019 Sesto-Fiorentin,
| | - Olivier Hernandez
- Sciences Chimiques de Rennes, UMR 6226 CNRS-Université de Rennes1, Inorganic Materials: Soft Chemistry and Reactivity of Solids, Campus de Beaulieu, F-35042 Rennes, France, Institut Laue-Langevin, BP 156 X, F-38042 Grenoble Cedex, France, Department of Inorganic, Physical and Materials Chemistry and NIS Center of Excellence, and INSTM “Centro di Riferimento”, University of Turin, Italy, European Laboratory for Non-Linear Spectroscopy, University of Florence, Polo Scientifico, I-50019 Sesto-Fiorentin,
| | - Monica Ceretti
- Sciences Chimiques de Rennes, UMR 6226 CNRS-Université de Rennes1, Inorganic Materials: Soft Chemistry and Reactivity of Solids, Campus de Beaulieu, F-35042 Rennes, France, Institut Laue-Langevin, BP 156 X, F-38042 Grenoble Cedex, France, Department of Inorganic, Physical and Materials Chemistry and NIS Center of Excellence, and INSTM “Centro di Riferimento”, University of Turin, Italy, European Laboratory for Non-Linear Spectroscopy, University of Florence, Polo Scientifico, I-50019 Sesto-Fiorentin,
| | - Marie Plazanet
- Sciences Chimiques de Rennes, UMR 6226 CNRS-Université de Rennes1, Inorganic Materials: Soft Chemistry and Reactivity of Solids, Campus de Beaulieu, F-35042 Rennes, France, Institut Laue-Langevin, BP 156 X, F-38042 Grenoble Cedex, France, Department of Inorganic, Physical and Materials Chemistry and NIS Center of Excellence, and INSTM “Centro di Riferimento”, University of Turin, Italy, European Laboratory for Non-Linear Spectroscopy, University of Florence, Polo Scientifico, I-50019 Sesto-Fiorentin,
| | - Kazimierz Conder
- Sciences Chimiques de Rennes, UMR 6226 CNRS-Université de Rennes1, Inorganic Materials: Soft Chemistry and Reactivity of Solids, Campus de Beaulieu, F-35042 Rennes, France, Institut Laue-Langevin, BP 156 X, F-38042 Grenoble Cedex, France, Department of Inorganic, Physical and Materials Chemistry and NIS Center of Excellence, and INSTM “Centro di Riferimento”, University of Turin, Italy, European Laboratory for Non-Linear Spectroscopy, University of Florence, Polo Scientifico, I-50019 Sesto-Fiorentin,
| | - Carlo Lamberti
- Sciences Chimiques de Rennes, UMR 6226 CNRS-Université de Rennes1, Inorganic Materials: Soft Chemistry and Reactivity of Solids, Campus de Beaulieu, F-35042 Rennes, France, Institut Laue-Langevin, BP 156 X, F-38042 Grenoble Cedex, France, Department of Inorganic, Physical and Materials Chemistry and NIS Center of Excellence, and INSTM “Centro di Riferimento”, University of Turin, Italy, European Laboratory for Non-Linear Spectroscopy, University of Florence, Polo Scientifico, I-50019 Sesto-Fiorentin,
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265
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Investigation of the Structural and Catalytic Requirements for High-Performance SOFC Anodes Formed by Infiltration of LSCM. ACTA ACUST UNITED AC 2009. [DOI: 10.1149/1.3065971] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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266
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A Cu–CeO[sub 2]-LDC Composite Anode for LSGM Electrolyte-Supported Solid Oxide Fuel Cells. ACTA ACUST UNITED AC 2009. [DOI: 10.1149/1.3117213] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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267
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Savaniu CD, Irvine JTS. Reduction studies and evaluation of surface modified A-site deficient La-doped SrTiO3 as anode material for IT-SOFCs. ACTA ACUST UNITED AC 2009. [DOI: 10.1039/b912305a] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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268
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Bhella SS, Kuti LM, Li Q, Thangadurai V. Electrical transport properties of In-doped Ce1−xInxO2−δ (x = 0.1; 0.2). Dalton Trans 2009:9520-8. [DOI: 10.1039/b910335j] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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269
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Cimenti M, Hill JM. Direct utilization of ethanol on ceria-based anodes for solid oxide fuel cells. ASIA-PAC J CHEM ENG 2009. [DOI: 10.1002/apj.182] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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270
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Serra JM, Vert VB. Optimization of oxygen activation fuel-cell electrocatalysts by combinatorial designs. CHEMSUSCHEM 2009; 2:957-961. [PMID: 19731283 DOI: 10.1002/cssc.200900149] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Affiliation(s)
- José M Serra
- Instituto de Tecnología Química, Universidad Politecnica de Valencia, 46022 Valencia, Spain.
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271
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JIA K, ZHANG H, LI W. Effect of Morphology of the Ceria Support on the Activity of Au/CeO2 Catalysts for CO Oxidation. CHINESE JOURNAL OF CATALYSIS 2008. [DOI: 10.1016/s1872-2067(09)60006-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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272
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Ding D, Liu Z, Li L, Xia C. An octane-fueled low temperature solid oxide fuel cell with Ru-free anodes. Electrochem commun 2008. [DOI: 10.1016/j.elecom.2008.06.026] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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273
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Tsipis EV, Kharton VV. Electrode materials and reaction mechanisms in solid oxide fuel cells: a brief review. J Solid State Electrochem 2008. [DOI: 10.1007/s10008-008-0611-6] [Citation(s) in RCA: 348] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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274
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Marrero-López D, Ruiz-Morales J, Peña-Martínez J, Canales-Vázquez J, Núñez P. Preparation of thin layer materials with macroporous microstructure for SOFC applications. J SOLID STATE CHEM 2008. [DOI: 10.1016/j.jssc.2008.01.008] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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275
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Morata A, Chesnaud A, Tarancón A, Estradé S, Peiró F, Morante J, Dezanneau G. A Versatile and Low‐Toxicity Route for the Production of Electroceramic Oxide Nanopowders. Eur J Inorg Chem 2008. [DOI: 10.1002/ejic.200701026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Alejandro Morata
- Electronics Department, University of Barcelona, C/Martí i Franquès, Barcelona 08028, Spain
| | - Anthony Chesnaud
- Laboratoire Structures, Propriétés et Modélisation des Solides, Ecole Centrale Paris, Grande voie des vignes, 92295 Châtenay‐Malabry, France
| | - Alberto Tarancón
- Electronics Department, University of Barcelona, C/Martí i Franquès, Barcelona 08028, Spain
| | - Sonia Estradé
- Electronics Department, University of Barcelona, C/Martí i Franquès, Barcelona 08028, Spain
| | - Francesca Peiró
- Electronics Department, University of Barcelona, C/Martí i Franquès, Barcelona 08028, Spain
| | - Joan‐Ramon Morante
- Electronics Department, University of Barcelona, C/Martí i Franquès, Barcelona 08028, Spain
| | - Guilhem Dezanneau
- Laboratoire Structures, Propriétés et Modélisation des Solides, Ecole Centrale Paris, Grande voie des vignes, 92295 Châtenay‐Malabry, France
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276
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Sadykov VA, Mezentseva NV, Bunina RV, Alikina GM, Lukashevich AI, Kharlamova TS, Rogov VA, Zaikovskii VI, Ishchenko AV, Krieger TA, Bobrenok OF, Smirnova A, Irvine J, Vasylyev OD. Effect of complex oxide promoters and Pd on activity and stability of Ni/YSZ (ScSZ) cermets as anode materials for IT SOFC. Catal Today 2008. [DOI: 10.1016/j.cattod.2007.10.064] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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277
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Hayward MA, Rosseinsky MJ. Materials chemistry: cool conditions for mobile ions. Nature 2008; 450:960-1. [PMID: 18075571 DOI: 10.1038/450960a] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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278
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279
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280
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281
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282
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Brett DJL, Atkinson A, Brandon NP, Skinner SJ. Intermediate temperature solid oxide fuel cells. Chem Soc Rev 2008; 37:1568-78. [DOI: 10.1039/b612060c] [Citation(s) in RCA: 1064] [Impact Index Per Article: 66.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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283
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Song HS, Hyun SH, Kim J, Lee HW, Moon J. A nanocomposite material for highly durable solid oxide fuel cell cathodes. ACTA ACUST UNITED AC 2008. [DOI: 10.1039/b714888g] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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284
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Busawon AN, Sarantaridis D, Atkinson A. Ni Infiltration as a Possible Solution to the Redox Problem of SOFC Anodes. ACTA ACUST UNITED AC 2008. [DOI: 10.1149/1.2959078] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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285
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Bessler WG, Gewies S, Vogler M. A new framework for physically based modeling of solid oxide fuel cells. Electrochim Acta 2007. [DOI: 10.1016/j.electacta.2007.08.030] [Citation(s) in RCA: 192] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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286
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Kendrick E, Kendrick J, Knight KS, Islam MS, Slater PR. Cooperative mechanisms of fast-ion conduction in gallium-based oxides with tetrahedral moieties. NATURE MATERIALS 2007; 6:871-875. [PMID: 17952081 DOI: 10.1038/nmat2039] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Accepted: 09/17/2007] [Indexed: 05/25/2023]
Abstract
The need for greater energy efficiency has garnered increasing support for the use of fuel-cell technology, a prime example being the solid-oxide fuel cell. A crucial requirement for such devices is a good ionic (O(2-) or H+) conductor as the electrolyte. Traditionally, fluorite- and perovskite-type oxides have been targeted, although there is growing interest in alternative structure types for intermediate-temperature (400-700 ( composite function)C) solid-oxide fuel cells. In particular, structures containing tetrahedral moieties, such as La(1-x)Ca(x)MO(4-x/2)(M=Ta,Nb,P) (refs 7,8), La(1-x)Ba(1+x)GaO(4-x/2) (refs 9,10) and La(9.33+x)Si(6)O(26+3x/2) (ref. 11), have been attracting considerable attention recently. However, an atomic-scale understanding of the conduction mechanisms in these systems is still lacking; such mechanistic detail is important for developing strategies for optimizing the conductivity, as well as identifying next-generation materials. In this context, we report a combined experimental and computational modelling study of the La(1-x)Ba(1+x)GaO(4-x/2) system, which exhibits both proton and oxide-ion conduction. Here we show that oxide-ion conduction proceeds via a cooperative 'cog-wheel'-type process involving the breaking and re-forming of Ga(2)O(7) units, whereas the rate-limiting step for proton conduction is intra-tetrahedron proton transfer. Both mechanisms are unusual for ceramic oxide materials, and similar cooperative processes may be important in related systems containing tetrahedral moieties.
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Affiliation(s)
- Emma Kendrick
- Materials Chemistry, UniS Materials Institute, University of Surrey, Guildford GU2 7XH, UK
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287
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Effect of structural, redox and acid characteristics of MxOy/ZrO2(Al2O3) (M-Mn, Co, Cr) oxide nanocomposites on their catalytic properties in the deep oxidation of methane. THEOR EXP CHEM+ 2007. [DOI: 10.1007/s11237-007-0049-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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288
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Improvement of the electrochemical properties of novel solid oxide fuel cell anodes, La0.75Sr0.25Cr0.5Mn0.5O3−δ and La4Sr8Ti11Mn0.5Ga0.5O37.5−δ, using Cu–YSZ-based cermets. Electrochim Acta 2007. [DOI: 10.1016/j.electacta.2007.05.060] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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289
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290
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Chedrik VI, Vasil’ev AD, Orlik SN. Effect of the composition of nickel-containing composites based on stabilised zirconia on catalytic activity in methane steam conversion. THEOR EXP CHEM+ 2007. [DOI: 10.1007/s11237-007-0031-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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291
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Pomfret MB, Owrutsky JC, Walker RA. In Situ Studies of Fuel Oxidation in Solid Oxide Fuel Cells. Anal Chem 2007; 79:2367-72. [PMID: 17295449 DOI: 10.1021/ac062189o] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Existing electrochemical experiments and models of fuel oxidation postulate about the importance of different oxidation pathways and relative fuel conversion efficiencies, but specific information is often lacking. Experiments described below present the first direct, in situ measurements of relevant chemical species formed on solid oxide fuel cell (SOFC) cermet anodes operating with both butane and CO fuel feeds. Raman spectroscopy is used to acquire vibrational spectra from SOFC anodes at 715 degrees C during operation. Both C4H10 and CO form graphitic intermediates. In the limit of a large oxide flux, excess butane forms ordered graphite but only transiently. At higher cell potentials (e.g., less current being drawn) ordered and disordered graphite form on the Ni cermet anode following exposure to butane, and under open circuit voltage (OCV) conditions the graphite persists indefinitely. The chemistry of CO oxidation is such that ordered graphite and a Ni-COO intermediate form only at intermediate cell potentials. Concurrent voltammetry studies show that the formation of graphite with butane at OCV leads first to decreased cell performance after exposure to 25 cm3 butane, then recovered performance after 75 cm3. CO voltammetry data show that at lower potentials the oxide flux through the YSZ electrolyte is sufficient to oxidize the Ni in the anode especially near the interface with the electrolyte.
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Affiliation(s)
- Michael B Pomfret
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA
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292
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Gross MD, Vohs JM, Gorte RJ. Recent progress in SOFC anodes for direct utilization of hydrocarbons. ACTA ACUST UNITED AC 2007. [DOI: 10.1039/b702633a] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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293
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294
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Kendrick E, Islam MS, Slater PR. Developing apatites for solid oxide fuel cells: insight into structural, transport and doping properties. ACTA ACUST UNITED AC 2007. [DOI: 10.1039/b704426g] [Citation(s) in RCA: 216] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Ruiz-Morales JC, Canales-Vázquez J, Savaniu C, Marrero-López D, Núñez P, Zhou W, Irvine JTS. A new anode for solid oxide fuel cells with enhanced OCV under methane operation. Phys Chem Chem Phys 2007; 9:1821-30. [PMID: 17415494 DOI: 10.1039/b617266k] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new SOFC anode material based upon oxygen excess perovskite related phases has been synthesised. The material shows better electrochemical performance than other alternative new anodes and comparable performance to the state-of-art of the electrodes, Ni-YSZ cermets, under pure hydrogen. Furthermore, this material shows an enhanced performance under methane operation with high open circuit voltages, i.e. 1.2-1.4 V at 950 degrees C, without using steam excess. The effect of the anode configuration was tested in one and four layer configurations. The optimised electrode polarisation resistances were just 0.12 ohm cm(2) and 0.36 ohm cm(2), at 950 degrees C, in humidified H(2) and humidified CH(4), respectively. Power densities of 0.5 W cm(-2) and 0.35 W cm(-2) were obtained in the same conditions. A very low anodic overpotential of 100 mV at 1 A cm(-2) was obtained under humidified H(2) at 950 degrees C. Samples were tested for two days in reducing and oxidising conditions, alternating heating and cooling processes from 850 degrees C to 950 degrees C, showing stable electrode performance and open circuit voltages. The results show that the substituted strontium titanates are very promising anode materials for SOFC.
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Affiliation(s)
- Juan C Ruiz-Morales
- School of Chemistry, University of St Andrews, St Andrews, Fife, UK KY16 9ST
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Ceria Nanocoating for Sulfur Tolerant Ni-Based Anodes of Solid Oxide Fuel Cells. ACTA ACUST UNITED AC 2007. [DOI: 10.1149/1.2748630] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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299
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Effects of Sr/Ti-ratio in SrTiO3-based SOFC anodes investigated by the use of cone-shaped electrodes. Electrochim Acta 2006. [DOI: 10.1016/j.electacta.2006.03.096] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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300
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Tao S, Irvine JTS, Plint SM. Methane Oxidation at Redox Stable Fuel Cell Electrode La0.75Sr0.25Cr0.5Mn0.5O3-δ. J Phys Chem B 2006; 110:21771-6. [PMID: 17064138 DOI: 10.1021/jp062376q] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Because of its widespread availability, natural gas is the most important fuel for early application of stationary fuel cells, and furthermore, methane containing biogases are one of the most promising renewable energy alternatives; thus, it is very important to be able to efficiently utilize methane in fuel cells. Typically, external steam reforming is applied to allow methane utilization in high temperature fuel cells; however, direct oxidation will provide a much better solution. Recently, we reported good electrochemical performance for an oxide anode La0.75Sr0.25Cr0.5Mn0.5O3 (LSCM) in low moisture (3% H2O) H2 and CH4 fuels without significant coking in CH4. Here, we investigate the catalytic activity of this oxide with respect to its ability to utilize methane. This oxide is found to exhibit fairly low reforming activity for both H2O and CO2 reforming but is active for methane oxidation. LSCM is found to be a full oxidation catalyst rather than a partial oxidation catalyst as CO2 production dominates CO production even in CH4-rich CH4/O2 mixtures. X-ray adsorption spectroscopy was utilized to confirm that Mn was the redox active species, clearly demonstrating that this material has the oxidation catalytic behavior that might be expected from a Mn perovskite and that the Cr ion is only present to ensure stability under fuel atmospheres.
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Affiliation(s)
- Shanwen Tao
- School of Chemistry, University of St. Andrews, Fife KY16 9ST, Scotland, United Kingdom.
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