Wollstadt, Stephan ; Clemens, Oliver (2024)
On the Impact of the Degree of Fluorination on the ORR Limiting Processes within Iron Based Catalysts: A Model Study on Symmetrical Films of Barium Ferrate.
In: Materials, 2020, 13 (11)
doi: 10.26083/tuprints-00016983
Artikel, Zweitveröffentlichung, Verlagsversion
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Kurzbeschreibung (Abstract)
In this study, symmetrical films of BaFeO₂.₆₇, BaFeO₂.₃₃F₀.₃₃ and BaFeO₂F were synthesized and the oxygen uptake and conduction was investigated by high temperature impedance spectroscopy under an oxygen atmosphere. The data were analyzed on the basis of an impedance model designed for highly porous mixed ionic electronic conducting (MIEC) electrodes. Variable temperature X-ray diffraction experiments were utilized to estimate the stability window of the oxyfluoride compounds, which yielded a degradation temperature for BaFeO₂.₃₃F₀.₃₃ of 590 °C and a decomposition temperature for BaFeO₂F of 710 °C. The impedance study revealed a significant change of the catalytic behavior in dependency of the fluorine content. BaFeO₂.₆₇ revealed a bulk-diffusion limited process, while BaFeO₂.₃₃F₀.₃₃ appeared to exhibit a fast bulk diffusion and a utilization region δ larger than the electrode thickness L (8 μm). In contrast, BaFeO₂F showed very area specific resistances due to the lack of oxygen vacancies. The activation energy for the uptake and conduction process of oxygen was found to be 0.07/0.29 eV (temperature range-dependent), 0.33 eV and 0.67 eV for BaFeO₂.₆₇, BaFeO₂.₃₃F₀.₃₃ and BaFeO₂F, respectively.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2024 |
| Autor(en): | Wollstadt, Stephan ; Clemens, Oliver |
| Art des Eintrags: | Zweitveröffentlichung |
| Titel: | On the Impact of the Degree of Fluorination on the ORR Limiting Processes within Iron Based Catalysts: A Model Study on Symmetrical Films of Barium Ferrate |
| Sprache: | Englisch |
| Publikationsjahr: | 15 Januar 2024 |
| Ort: | Darmstadt |
| Publikationsdatum der Erstveröffentlichung: | 2020 |
| Ort der Erstveröffentlichung: | Basel |
| Verlag: | MDPI |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Materials |
| Jahrgang/Volume einer Zeitschrift: | 13 |
| (Heft-)Nummer: | 11 |
| Kollation: | 22 Seiten |
| DOI: | 10.26083/tuprints-00016983 |
| URL / URN: | https://tuprints.ulb.tu-darmstadt.de/16983 |
| Zugehörige Links: | |
| Herkunft: | Zweitveröffentlichung DeepGreen |
| Kurzbeschreibung (Abstract): | In this study, symmetrical films of BaFeO₂.₆₇, BaFeO₂.₃₃F₀.₃₃ and BaFeO₂F were synthesized and the oxygen uptake and conduction was investigated by high temperature impedance spectroscopy under an oxygen atmosphere. The data were analyzed on the basis of an impedance model designed for highly porous mixed ionic electronic conducting (MIEC) electrodes. Variable temperature X-ray diffraction experiments were utilized to estimate the stability window of the oxyfluoride compounds, which yielded a degradation temperature for BaFeO₂.₃₃F₀.₃₃ of 590 °C and a decomposition temperature for BaFeO₂F of 710 °C. The impedance study revealed a significant change of the catalytic behavior in dependency of the fluorine content. BaFeO₂.₆₇ revealed a bulk-diffusion limited process, while BaFeO₂.₃₃F₀.₃₃ appeared to exhibit a fast bulk diffusion and a utilization region δ larger than the electrode thickness L (8 μm). In contrast, BaFeO₂F showed very area specific resistances due to the lack of oxygen vacancies. The activation energy for the uptake and conduction process of oxygen was found to be 0.07/0.29 eV (temperature range-dependent), 0.33 eV and 0.67 eV for BaFeO₂.₆₇, BaFeO₂.₃₃F₀.₃₃ and BaFeO₂F, respectively. |
| Freie Schlagworte: | thin film fluorination, ORR catalysts, oxyfluorides, barium ferrate, impedance spectroscopy |
| Status: | Verlagsversion |
| URN: | urn:nbn:de:tuda-tuprints-169830 |
| Zusätzliche Informationen: | This article belongs to the Section Energy Materials |
| Sachgruppe der Dewey Dezimalklassifikatin (DDC): | 500 Naturwissenschaften und Mathematik > 540 Chemie 600 Technik, Medizin, angewandte Wissenschaften > 660 Technische Chemie |
| Fachbereich(e)/-gebiet(e): | 11 Fachbereich Material- und Geowissenschaften 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Fachgebiet Materialdesign durch Synthese |
| Hinterlegungsdatum: | 15 Jan 2024 14:08 |
| Letzte Änderung: | 16 Jan 2024 07:49 |
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| Suche nach Titel in: | TUfind oder in Google |
Verfügbare Versionen dieses Eintrags
- On the Impact of the Degree of Fluorination on the ORR Limiting Processes within Iron Based Catalysts: A Model Study on Symmetrical Films of Barium Ferrate. (deposited 15 Jan 2024 14:08) [Gegenwärtig angezeigt]
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