Roth, C. ; Benker, N. ; Mazurek, M. ; Scheiba, F. ; Fuess, H. (2007)
Pt-Ru fuel cell catalysts subjected to H2, CO, N2 and air atmosphere: An X-ray absorption study.
In: Applied Catalysis A: General, 319
doi: 10.1016/j.apcata.2006.11.018
Artikel, Bibliographie
Kurzbeschreibung (Abstract)
In situ X-ray absorption spectroscopy (XAS) measurements were carried out on commercial carbon-supported Pt, Ru and Pt-Ru alloy electrocatalysts as well as a Pt/Ru mixture electrocatalyst in a specifically designed reactor/furnace set-up at the Pt L3 and the Ru K edge. The catalysts were heated to 100 °C and subjected to different atmospheres – 5% H2/N2, 5% CO/N2, N2, air – of interest for fuel cell operation. X-ray absorption spectroscopy was used to follow changes in the catalyst structure, most importantly particle growth, oxidation, and (de-)alloying. Alloying is observed to be advantageous, as it decreases particle growth and oxidation tendency in the catalysts. Initially, all electrocatalysts contained large amounts of the respective oxides, as indicated by pronounced white-line intensities in the XANES spectra, whereas the catalysts were reduced to the metallic state upon exposure to hydrogen. In CO atmosphere, however, ruthenium oxides remain stable, depending on the Pt to Ru site distribution: it is assumed that Pt in contact with Ru acts as a “catalyst” for the reduction of ruthenium oxides and strengthens the Ru–CO bond favouring it over Ru-O (ligand effect). Consequently, the share of ruthenium oxides in the Pt-Ru alloy decreases in 5% CO/N2, whereas for the Pt/Ru mixture and the pure Ru it does not change significantly.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2007 |
| Autor(en): | Roth, C. ; Benker, N. ; Mazurek, M. ; Scheiba, F. ; Fuess, H. |
| Art des Eintrags: | Bibliographie |
| Titel: | Pt-Ru fuel cell catalysts subjected to H2, CO, N2 and air atmosphere: An X-ray absorption study |
| Sprache: | Englisch |
| Publikationsjahr: | 1 März 2007 |
| Verlag: | Elsevier Science Publishing Company |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Applied Catalysis A: General |
| Jahrgang/Volume einer Zeitschrift: | 319 |
| DOI: | 10.1016/j.apcata.2006.11.018 |
| Kurzbeschreibung (Abstract): | In situ X-ray absorption spectroscopy (XAS) measurements were carried out on commercial carbon-supported Pt, Ru and Pt-Ru alloy electrocatalysts as well as a Pt/Ru mixture electrocatalyst in a specifically designed reactor/furnace set-up at the Pt L3 and the Ru K edge. The catalysts were heated to 100 °C and subjected to different atmospheres – 5% H2/N2, 5% CO/N2, N2, air – of interest for fuel cell operation. X-ray absorption spectroscopy was used to follow changes in the catalyst structure, most importantly particle growth, oxidation, and (de-)alloying. Alloying is observed to be advantageous, as it decreases particle growth and oxidation tendency in the catalysts. Initially, all electrocatalysts contained large amounts of the respective oxides, as indicated by pronounced white-line intensities in the XANES spectra, whereas the catalysts were reduced to the metallic state upon exposure to hydrogen. In CO atmosphere, however, ruthenium oxides remain stable, depending on the Pt to Ru site distribution: it is assumed that Pt in contact with Ru acts as a “catalyst” for the reduction of ruthenium oxides and strengthens the Ru–CO bond favouring it over Ru-O (ligand effect). Consequently, the share of ruthenium oxides in the Pt-Ru alloy decreases in 5% CO/N2, whereas for the Pt/Ru mixture and the pure Ru it does not change significantly. |
| Freie Schlagworte: | Electrocatalysts, Fuel cell, Heat-treatment, In situ, Pt, Pt-Ru, X-ray absorption spectroscopy |
| Fachbereich(e)/-gebiet(e): | 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Erneuerbare Energien 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Fachgebiet Strukturforschung 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft 11 Fachbereich Material- und Geowissenschaften |
| Hinterlegungsdatum: | 20 Feb 2013 12:19 |
| Letzte Änderung: | 05 Mär 2013 10:05 |
| PPN: | |
| Sponsoren: | Financial support of the Deutsche Forschungsgemeinschaft is gratefully acknowledged. |
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