Filtschew, Anastasia ; Hess, Christian (2024)
Unravelling the mechanism of NO and NO₂ storage in ceria: The role of defects and Ce-O surface sites.
In: Applied Catalysis B: Environment and Energy, 2018, 237
doi: 10.26083/tuprints-00028219
Artikel, Zweitveröffentlichung, Postprint
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Kurzbeschreibung (Abstract)
Ceria is an important NOₓ storage material often used in combination with barium or zirconia. To elucidate the NO and NO₂ storage mechanism in ceria we employed in situ Raman spectroscopy coupled with simultaneous FT-IR gas-phase analysis. The Raman spectra reveal new information about the dynamics of the surface and bulk structure of ceria upon NOₓ exposure at 30 °C besides the identification of nitrite and nitrate adsorbates. In particular, Raman spectra provide direct evidence of the involvement of Ce-O surface sites so far not accessible by spectroscopic methods. These Ce-O sites play a key role for NOₓ storage, as their amount strongly influences the NOₓ storage capacity. A reduction of ceria prior to NOₓ exposure resulted in a lower NOₓ storage capacity, as long as no strong oxidizing agent (e.g. NO₂) was present to form new Ce-O sites. In the case of NO storage at 30 °C, new reaction pathways are postulated that describe the activation of gas-phase oxygen for ionic nitrite transformation and formation of new NOₓ adsorption sites. However, it is shown that the activated oxygen species is not a peroxide, as no correlation was found between the peroxides and formed nitrate and nitrite species. Based on our results, a mechanism for NO and NO₂ storage in ceria was formulated.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2024 |
| Autor(en): | Filtschew, Anastasia ; Hess, Christian |
| Art des Eintrags: | Zweitveröffentlichung |
| Titel: | Unravelling the mechanism of NO and NO₂ storage in ceria: The role of defects and Ce-O surface sites |
| Sprache: | Englisch |
| Publikationsjahr: | 5 Dezember 2024 |
| Ort: | Darmstadt |
| Publikationsdatum der Erstveröffentlichung: | 23 Juni 2018 |
| Ort der Erstveröffentlichung: | Amsterdam |
| Verlag: | Elsevier |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Applied Catalysis B: Environment and Energy |
| Jahrgang/Volume einer Zeitschrift: | 237 |
| Kollation: | 40 Seiten |
| DOI: | 10.26083/tuprints-00028219 |
| URL / URN: | https://tuprints.ulb.tu-darmstadt.de/28219 |
| Zugehörige Links: | |
| Herkunft: | Zweitveröffentlichungsservice |
| Kurzbeschreibung (Abstract): | Ceria is an important NOₓ storage material often used in combination with barium or zirconia. To elucidate the NO and NO₂ storage mechanism in ceria we employed in situ Raman spectroscopy coupled with simultaneous FT-IR gas-phase analysis. The Raman spectra reveal new information about the dynamics of the surface and bulk structure of ceria upon NOₓ exposure at 30 °C besides the identification of nitrite and nitrate adsorbates. In particular, Raman spectra provide direct evidence of the involvement of Ce-O surface sites so far not accessible by spectroscopic methods. These Ce-O sites play a key role for NOₓ storage, as their amount strongly influences the NOₓ storage capacity. A reduction of ceria prior to NOₓ exposure resulted in a lower NOₓ storage capacity, as long as no strong oxidizing agent (e.g. NO₂) was present to form new Ce-O sites. In the case of NO storage at 30 °C, new reaction pathways are postulated that describe the activation of gas-phase oxygen for ionic nitrite transformation and formation of new NOₓ adsorption sites. However, it is shown that the activated oxygen species is not a peroxide, as no correlation was found between the peroxides and formed nitrate and nitrite species. Based on our results, a mechanism for NO and NO₂ storage in ceria was formulated. |
| Freie Schlagworte: | Ceria, NOx storage mechanism, In situ Raman, Defects, NOx adsorber |
| Status: | Postprint |
| URN: | urn:nbn:de:tuda-tuprints-282193 |
| Sachgruppe der Dewey Dezimalklassifikatin (DDC): | 500 Naturwissenschaften und Mathematik > 540 Chemie |
| Fachbereich(e)/-gebiet(e): | 07 Fachbereich Chemie 07 Fachbereich Chemie > Eduard Zintl-Institut 07 Fachbereich Chemie > Eduard Zintl-Institut > Fachgebiet Physikalische Chemie |
| Hinterlegungsdatum: | 05 Dez 2024 13:37 |
| Letzte Änderung: | 09 Dez 2024 12:32 |
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- Unravelling the mechanism of NO and NO₂ storage in ceria: The role of defects and Ce-O surface sites. (deposited 05 Dez 2024 13:37) [Gegenwärtig angezeigt]
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