In-situ scanning photoelectron microscopy study of operating (La,Sr)FeO3-based NOx-sensing surfaces
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| Title: | In-situ scanning photoelectron microscopy study of operating (La,Sr)FeO |
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| Authors: | Backhaus-Ricoult, M.1 backhausm@corning.com, Adib, K.1, Work, K.1, Badding, M.1, Ketcham, T.1, Amati, M.2, Gregoratti, L.2 |
| Source: | Solid State Ionics. Oct2012, Vol. 225, p716-726. 11p. |
| Subjects: | Scanning electron microscopy, Iron oxides, Nitric oxide, Gas detectors, Impedance spectroscopy, Surface chemistry, High temperatures |
| Abstract: | Abstract: Scanning photoelectron microscopy and impedance spectroscopy were used to study simultaneously the impact of NO gas on surface chemistry and the electrochemical response of electrolyte-supported (La1−xSrx)FeO3−δ (LSF) sensing layers in electrochemical NOx sensors, during high-temperature operation. Electrochemical model cells were fabricated by screen printing macro- and micro-patterned thin films on zirconia electrolyte. Cell bias, temperature and NO/O2 gas ratio were varied during the experiments. LSF/3YSZ sensing layers remained stable over a wide temperature-bias range in an oxygen-containing environment. LSF compositions with low strontium content (x=0.2) did not undergo any changes in their surface chemistry, while compositions with higher strontium level (x=0.4) showed partial reduction of surface iron at low oxygen chemical potential. Upon exposure to NO gas at low oxygen partial pressure, NO was observed to dissociate on the LSF surface and form chemisorbed O- and N-adatoms with strong interactions to surface iron or zirconium. Concentration and stability of these ad-complexes increased with the NO/O2 ratio, cathodic bias and decreasing temperature. At low NO level in the gas, NO was observed to interact preferentially with iron atoms at the LSF surface and the surface reaction was reversible. At high NO/O2 ratios and low temperatures, irreversible formation of surface ad-complexes was observed, with reduced iron and zirconium, and caused even new phase formation. Simultaneous assessment of surface chemistry and cell impedance demonstrated that modifications in surface chemistry directly affected the oxygen exchange rate in the cell. In the presence of NO, the sensing oxide resistance decreased for zero or small bias. For large bias, no additional decrease in cell resistance was observed beyond the corresponding intrinsic cell performance in oxygen. Under these conditions, again, the particular cell response depended on the strontium substitution level in LSF, favoring lower redox-stability and thus a more complicated cell response to NO gas for high strontium level. [Copyright &y& Elsevier] |
| Copyright of Solid State Ionics is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Text: Availability: 0 |
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| Header | DbId: egs DbLabel: Engineering Source An: 82679751 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: In-situ scanning photoelectron microscopy study of operating (La,Sr)FeO<subscript>3</subscript>-based NO<subscript>x</subscript>-sensing surfaces – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Backhaus-Ricoult%2C+M%2E%22">Backhaus-Ricoult, M.</searchLink><relatesTo>1</relatesTo><i> backhausm@corning.com</i><br /><searchLink fieldCode="AR" term="%22Adib%2C+K%2E%22">Adib, K.</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Work%2C+K%2E%22">Work, K.</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Badding%2C+M%2E%22">Badding, M.</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Ketcham%2C+T%2E%22">Ketcham, T.</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Amati%2C+M%2E%22">Amati, M.</searchLink><relatesTo>2</relatesTo><br /><searchLink fieldCode="AR" term="%22Gregoratti%2C+L%2E%22">Gregoratti, L.</searchLink><relatesTo>2</relatesTo> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Solid+State+Ionics%22">Solid State Ionics</searchLink>. Oct2012, Vol. 225, p716-726. 11p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Scanning+electron+microscopy%22">Scanning electron microscopy</searchLink><br /><searchLink fieldCode="DE" term="%22Iron+oxides%22">Iron oxides</searchLink><br /><searchLink fieldCode="DE" term="%22Nitric+oxide%22">Nitric oxide</searchLink><br /><searchLink fieldCode="DE" term="%22Gas+detectors%22">Gas detectors</searchLink><br /><searchLink fieldCode="DE" term="%22Impedance+spectroscopy%22">Impedance spectroscopy</searchLink><br /><searchLink fieldCode="DE" term="%22Surface+chemistry%22">Surface chemistry</searchLink><br /><searchLink fieldCode="DE" term="%22High+temperatures%22">High temperatures</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Abstract: Scanning photoelectron microscopy and impedance spectroscopy were used to study simultaneously the impact of NO gas on surface chemistry and the electrochemical response of electrolyte-supported (La1−xSrx)FeO3−δ (LSF) sensing layers in electrochemical NOx sensors, during high-temperature operation. Electrochemical model cells were fabricated by screen printing macro- and micro-patterned thin films on zirconia electrolyte. Cell bias, temperature and NO/O2 gas ratio were varied during the experiments. LSF/3YSZ sensing layers remained stable over a wide temperature-bias range in an oxygen-containing environment. LSF compositions with low strontium content (x=0.2) did not undergo any changes in their surface chemistry, while compositions with higher strontium level (x=0.4) showed partial reduction of surface iron at low oxygen chemical potential. Upon exposure to NO gas at low oxygen partial pressure, NO was observed to dissociate on the LSF surface and form chemisorbed O- and N-adatoms with strong interactions to surface iron or zirconium. Concentration and stability of these ad-complexes increased with the NO/O2 ratio, cathodic bias and decreasing temperature. At low NO level in the gas, NO was observed to interact preferentially with iron atoms at the LSF surface and the surface reaction was reversible. At high NO/O2 ratios and low temperatures, irreversible formation of surface ad-complexes was observed, with reduced iron and zirconium, and caused even new phase formation. Simultaneous assessment of surface chemistry and cell impedance demonstrated that modifications in surface chemistry directly affected the oxygen exchange rate in the cell. In the presence of NO, the sensing oxide resistance decreased for zero or small bias. For large bias, no additional decrease in cell resistance was observed beyond the corresponding intrinsic cell performance in oxygen. Under these conditions, again, the particular cell response depended on the strontium substitution level in LSF, favoring lower redox-stability and thus a more complicated cell response to NO gas for high strontium level. [Copyright &y& Elsevier] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Solid State Ionics is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1016/j.ssi.2012.03.007 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 11 StartPage: 716 Subjects: – SubjectFull: Scanning electron microscopy Type: general – SubjectFull: Iron oxides Type: general – SubjectFull: Nitric oxide Type: general – SubjectFull: Gas detectors Type: general – SubjectFull: Impedance spectroscopy Type: general – SubjectFull: Surface chemistry Type: general – SubjectFull: High temperatures Type: general Titles: – TitleFull: In-situ scanning photoelectron microscopy study of operating (La,Sr)FeO3-based NOx-sensing surfaces Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Backhaus-Ricoult, M. – PersonEntity: Name: NameFull: Adib, K. – PersonEntity: Name: NameFull: Work, K. – PersonEntity: Name: NameFull: Badding, M. – PersonEntity: Name: NameFull: Ketcham, T. – PersonEntity: Name: NameFull: Amati, M. – PersonEntity: Name: NameFull: Gregoratti, L. IsPartOfRelationships: – BibEntity: Dates: – D: 04 M: 10 Text: Oct2012 Type: published Y: 2012 Identifiers: – Type: issn-print Value: 01672738 Numbering: – Type: volume Value: 225 Titles: – TitleFull: Solid State Ionics Type: main |
| ResultId | 1 |
