The Chemical Evolution of the La[subscript 0.6]Sr[subscript 0.4]CoO[subscript 3−δ] Surface Under SOFC Operating Conditions and Its Implications for Electrochemical Oxygen Exchange Activity
Owing to its extraordinary high activity for catalysing the oxygen exchange reaction, strontium doped LaCoO[subscript 3] (LSC) is one of the most promising materials for solid oxide fuel cell (SOFC) cathodes. However, under SOFC operating conditions this material suffers from performance degradation...
| Main Authors: | , , , , , , , , , , , , , |
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| Other Authors: | |
| Format: | Article |
| Language: | English |
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Springer US
2019
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| Online Access: | http://hdl.handle.net/1721.1/121126 |
| _version_ | 1811071319566974976 |
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| author | Opitz, Alexander K Rameshan, Christoph Kubicek, Markus Rupp, Ghislain M Götsch, Thomas Blume, Raoul Hävecker, Michael Knop-Gericke, Axel Rupprechter, Günther Klötzer, Bernhard Fleig, Jürgen Opitz, Alexander K. Rupp, Ghislain M. Nenning, Andreas |
| author2 | Massachusetts Institute of Technology. Department of Materials Science and Engineering |
| author_facet | Massachusetts Institute of Technology. Department of Materials Science and Engineering Opitz, Alexander K Rameshan, Christoph Kubicek, Markus Rupp, Ghislain M Götsch, Thomas Blume, Raoul Hävecker, Michael Knop-Gericke, Axel Rupprechter, Günther Klötzer, Bernhard Fleig, Jürgen Opitz, Alexander K. Rupp, Ghislain M. Nenning, Andreas |
| author_sort | Opitz, Alexander K |
| collection | MIT |
| description | Owing to its extraordinary high activity for catalysing the oxygen exchange reaction, strontium doped LaCoO[subscript 3] (LSC) is one of the most promising materials for solid oxide fuel cell (SOFC) cathodes. However, under SOFC operating conditions this material suffers from performance degradation. This loss of electrochemical activity has been extensively studied in the past and an accumulation of strontium at the LSC surface has been shown to be responsible for most of the degradation effects. The present study sheds further light onto LSC surface changes also occurring under SOFC operating conditions. In-situ near ambient pressure X-ray photoelectron spectroscopy measurements were conducted at temperatures between 400 and 790 °C. Simultaneously, electrochemical impedance measurements were performed to characterise the catalytic activity of the LSC electrode surface for O[subscript 2] reduction. This combination allowed a correlation of the loss in electro-catalytic activity with the appearance of an additional La-containing Sr-oxide species at the LSC surface. This additional Sr-oxide species preferentially covers electrochemically active Co sites at the surface, and thus very effectively decreases the oxygen exchange performance of LSC. Formation of precipitates, in contrast, was found to play a less important role for the electrochemical degradation of LSC. Keywords: Oxygen reduction, SOFC cathode, Strontium segregation, NAP-XPS, Impedance spectroscopy, Perovskite-type electrode |
| first_indexed | 2024-09-23T08:49:20Z |
| format | Article |
| id | mit-1721.1/121126 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T08:49:20Z |
| publishDate | 2019 |
| publisher | Springer US |
| record_format | dspace |
| spelling | mit-1721.1/1211262022-09-23T14:48:27Z The Chemical Evolution of the La[subscript 0.6]Sr[subscript 0.4]CoO[subscript 3−δ] Surface Under SOFC Operating Conditions and Its Implications for Electrochemical Oxygen Exchange Activity Opitz, Alexander K Rameshan, Christoph Kubicek, Markus Rupp, Ghislain M Götsch, Thomas Blume, Raoul Hävecker, Michael Knop-Gericke, Axel Rupprechter, Günther Klötzer, Bernhard Fleig, Jürgen Opitz, Alexander K. Rupp, Ghislain M. Nenning, Andreas Massachusetts Institute of Technology. Department of Materials Science and Engineering Nenning, Andreas Owing to its extraordinary high activity for catalysing the oxygen exchange reaction, strontium doped LaCoO[subscript 3] (LSC) is one of the most promising materials for solid oxide fuel cell (SOFC) cathodes. However, under SOFC operating conditions this material suffers from performance degradation. This loss of electrochemical activity has been extensively studied in the past and an accumulation of strontium at the LSC surface has been shown to be responsible for most of the degradation effects. The present study sheds further light onto LSC surface changes also occurring under SOFC operating conditions. In-situ near ambient pressure X-ray photoelectron spectroscopy measurements were conducted at temperatures between 400 and 790 °C. Simultaneously, electrochemical impedance measurements were performed to characterise the catalytic activity of the LSC electrode surface for O[subscript 2] reduction. This combination allowed a correlation of the loss in electro-catalytic activity with the appearance of an additional La-containing Sr-oxide species at the LSC surface. This additional Sr-oxide species preferentially covers electrochemically active Co sites at the surface, and thus very effectively decreases the oxygen exchange performance of LSC. Formation of precipitates, in contrast, was found to play a less important role for the electrochemical degradation of LSC. Keywords: Oxygen reduction, SOFC cathode, Strontium segregation, NAP-XPS, Impedance spectroscopy, Perovskite-type electrode Austrian Science Fund (F4502/03/09) Helmholtz-Zentrum Geesthacht 2019-03-29T20:40:15Z 2019-03-29T20:40:15Z 2018-10 2019-02-20T04:52:01Z Article http://purl.org/eprint/type/JournalArticle 1022-5528 1572-9028 http://hdl.handle.net/1721.1/121126 Opitz, Alexander K. et al. “The Chemical Evolution of the La[subscript 0.6]Sr[subscript 0.4]CoO[subscript 3−δ] Surface Under SOFC Operating Conditions and Its Implications for Electrochemical Oxygen Exchange Activity.” Topics in Catalysis 61, no. 20 (October 20, 2018): 2129–2141. en https://doi.org/10.1007/s11244-018-1068-1 Topics in Catalysis Creative Commons Attribution https://creativecommons.org/licenses/by/4.0/ The Author(s) application/pdf Springer US Springer US |
| spellingShingle | Opitz, Alexander K Rameshan, Christoph Kubicek, Markus Rupp, Ghislain M Götsch, Thomas Blume, Raoul Hävecker, Michael Knop-Gericke, Axel Rupprechter, Günther Klötzer, Bernhard Fleig, Jürgen Opitz, Alexander K. Rupp, Ghislain M. Nenning, Andreas The Chemical Evolution of the La[subscript 0.6]Sr[subscript 0.4]CoO[subscript 3−δ] Surface Under SOFC Operating Conditions and Its Implications for Electrochemical Oxygen Exchange Activity |
| title | The Chemical Evolution of the La[subscript 0.6]Sr[subscript 0.4]CoO[subscript 3−δ] Surface Under SOFC Operating Conditions and Its Implications for Electrochemical Oxygen Exchange Activity |
| title_full | The Chemical Evolution of the La[subscript 0.6]Sr[subscript 0.4]CoO[subscript 3−δ] Surface Under SOFC Operating Conditions and Its Implications for Electrochemical Oxygen Exchange Activity |
| title_fullStr | The Chemical Evolution of the La[subscript 0.6]Sr[subscript 0.4]CoO[subscript 3−δ] Surface Under SOFC Operating Conditions and Its Implications for Electrochemical Oxygen Exchange Activity |
| title_full_unstemmed | The Chemical Evolution of the La[subscript 0.6]Sr[subscript 0.4]CoO[subscript 3−δ] Surface Under SOFC Operating Conditions and Its Implications for Electrochemical Oxygen Exchange Activity |
| title_short | The Chemical Evolution of the La[subscript 0.6]Sr[subscript 0.4]CoO[subscript 3−δ] Surface Under SOFC Operating Conditions and Its Implications for Electrochemical Oxygen Exchange Activity |
| title_sort | chemical evolution of the la subscript 0 6 sr subscript 0 4 coo subscript 3 δ surface under sofc operating conditions and its implications for electrochemical oxygen exchange activity |
| url | http://hdl.handle.net/1721.1/121126 |
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