Ziemba, Marc ; Weyel, Jakob ; Hess, Christian (2024)
Approaching C1 Reaction Mechanisms Using Combined Operando and Transient Analysis: A Case Study on Cu/CeO₂ Catalysts During LT-Water–Gas Shift Reaction.
In: ACS Catalysis, 2022, 12 (15)
doi: 10.26083/tuprints-00028244
Artikel, Zweitveröffentlichung, Postprint
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Kurzbeschreibung (Abstract)
The elucidation of reaction mechanisms is an essential part of catalysis research, providing approaches to improve catalysts or, ultimately, to design catalysts based on a profound understanding of their mode of operation. In the context of C1 processes, redox and/or associative mechanisms have been proposed in the literature, but their critical assessment has been a major challenge. Here, we highlight the importance of applying a combination of techniques suited to address both the redox properties and intermediate/adsorbate dynamics in a targeted manner. We illustrate our approach by exploring the mechanism of LT-WGS over low-loaded Cu/CeO₂ catalysts using different ceria morphologies (sheets, polyhedra, cubes, and rods) to study the influence of the surface termination. While the results from operando Raman and UV–vis spectroscopy are consistent with a redox mechanism, there is no direct correlation of activity with reducibility. Probing the subsurface/bulk oxygen dynamics using operando Raman F₂g analysis coupled with H₂¹⁸O highlights the importance of transport properties and the availability of oxygen at the surface. Transient IR spectra reveal the presence of different surface carbonates, none of which are directly involved in the reaction but rather act as spectator species, blocking active sites, as supported by the facet-dependent analysis. From transient IR spectroscopy there is no indication of the involvement of copper, suggesting that the catalytic effect of copper is mainly based on electronic effects. The results from the operando and transient analysis unequivocally support a redox mechanism for LT-WGS over Cu/CeO₂ catalysts and demonstrate the potential of our combined spectroscopic approach to distinguish between redox and associative mechanisms in oxide-supported metal catalysts.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2024 |
| Autor(en): | Ziemba, Marc ; Weyel, Jakob ; Hess, Christian |
| Art des Eintrags: | Zweitveröffentlichung |
| Titel: | Approaching C1 Reaction Mechanisms Using Combined Operando and Transient Analysis: A Case Study on Cu/CeO₂ Catalysts During LT-Water–Gas Shift Reaction |
| Sprache: | Englisch |
| Publikationsjahr: | 6 Dezember 2024 |
| Ort: | Darmstadt |
| Publikationsdatum der Erstveröffentlichung: | 20 Juli 2022 |
| Ort der Erstveröffentlichung: | Washington, DC |
| Verlag: | American Chemical Society |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | ACS Catalysis |
| Jahrgang/Volume einer Zeitschrift: | 12 |
| (Heft-)Nummer: | 15 |
| Kollation: | 32 Seiten |
| DOI: | 10.26083/tuprints-00028244 |
| URL / URN: | https://tuprints.ulb.tu-darmstadt.de/28244 |
| Zugehörige Links: | |
| Herkunft: | Zweitveröffentlichungsservice |
| Kurzbeschreibung (Abstract): | The elucidation of reaction mechanisms is an essential part of catalysis research, providing approaches to improve catalysts or, ultimately, to design catalysts based on a profound understanding of their mode of operation. In the context of C1 processes, redox and/or associative mechanisms have been proposed in the literature, but their critical assessment has been a major challenge. Here, we highlight the importance of applying a combination of techniques suited to address both the redox properties and intermediate/adsorbate dynamics in a targeted manner. We illustrate our approach by exploring the mechanism of LT-WGS over low-loaded Cu/CeO₂ catalysts using different ceria morphologies (sheets, polyhedra, cubes, and rods) to study the influence of the surface termination. While the results from operando Raman and UV–vis spectroscopy are consistent with a redox mechanism, there is no direct correlation of activity with reducibility. Probing the subsurface/bulk oxygen dynamics using operando Raman F₂g analysis coupled with H₂¹⁸O highlights the importance of transport properties and the availability of oxygen at the surface. Transient IR spectra reveal the presence of different surface carbonates, none of which are directly involved in the reaction but rather act as spectator species, blocking active sites, as supported by the facet-dependent analysis. From transient IR spectroscopy there is no indication of the involvement of copper, suggesting that the catalytic effect of copper is mainly based on electronic effects. The results from the operando and transient analysis unequivocally support a redox mechanism for LT-WGS over Cu/CeO₂ catalysts and demonstrate the potential of our combined spectroscopic approach to distinguish between redox and associative mechanisms in oxide-supported metal catalysts. |
| Freie Schlagworte: | Mechanism, Cu/CeO₂, Water−gas Shift, Operando Spectroscopy, Transient Spectroscopy, Raman, DRIFTS, UV−vis |
| Status: | Postprint |
| URN: | urn:nbn:de:tuda-tuprints-282444 |
| 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: | 06 Dez 2024 13:20 |
| Letzte Änderung: | 09 Dez 2024 12:51 |
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| Suche nach Titel in: | TUfind oder in Google |
Verfügbare Versionen dieses Eintrags
- Approaching C1 Reaction Mechanisms Using Combined Operando and Transient Analysis: A Case Study on Cu/CeO₂ Catalysts During LT-Water–Gas Shift Reaction. (deposited 06 Dez 2024 13:20) [Gegenwärtig angezeigt]
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