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The Chemical Evolution of the La0.6Sr0.4CoO3−δ Surface Under SOFC Operating Conditions and Its Implications for Electrochemical Oxygen Exchange Activity
- Source :
- Topics in Catalysis
- Publication Year :
- 2018
- Publisher :
- Springer Science and Business Media LLC, 2018.
-
Abstract
- Owing to its extraordinary high activity for catalysing the oxygen exchange reaction, strontium doped LaCoO3 (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 O2 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. Electronic supplementary material The online version of this article (10.1007/s11244-018-1068-1) contains supplementary material, which is available to authorized users.
- Subjects :
- Perovskite-type electrode
NAP-XPS
Materials science
Oxygen reduction
Impedance spectroscopy
chemistry.chemical_element
02 engineering and technology
010402 general chemistry
Electrochemistry
01 natural sciences
Oxygen
Catalysis
law.invention
X-ray photoelectron spectroscopy
law
SOFC cathode
Strontium segregation
General Chemistry
021001 nanoscience & nanotechnology
Cathode
0104 chemical sciences
Dielectric spectroscopy
chemistry
Chemical engineering
Electrode
Original Article
Solid oxide fuel cell
sense organs
0210 nano-technology
Subjects
Details
- ISSN :
- 15729028 and 10225528
- Volume :
- 61
- Database :
- OpenAIRE
- Journal :
- Topics in Catalysis
- Accession number :
- edsair.doi.dedup.....31032c4a68cd48c783f1bb7ea79e248d