bei Google ScholarTitelangaben
Roth, Christina ; Benker, Nathalie ; Mazurek, Marian ; Scheiba, Frieder ; Fuess, Hartmut:
Pt-Ru fuel cell catalysts subjected to H₂, CO, N₂ and air atmosphere : An X-ray absorption study.
In: Applied Catalysis A: General.
Bd. 319
(2007)
.
- S. 81-90.
ISSN 1873-3875
DOI: https://doi.org/10.1016/j.apcata.2006.11.018
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.
Weitere Angaben
| Publikationsform: | Artikel in einer Zeitschrift |
|---|---|
| Begutachteter Beitrag: | Ja |
| Keywords: | Electrocatalysts; Fuel cell; Heat-treatment; In situ; Pt; Pt-Ru; X-ray absorption spectroscopy |
| Institutionen der Universität: | Fakultäten > Fakultät für Ingenieurwissenschaften > Lehrstuhl Werkstoffverfahrenstechnik > Lehrstuhl Werkstoffverfahrenstechnik - Univ.-Prof. Dr. Christina Roth Fakultäten Fakultäten > Fakultät für Ingenieurwissenschaften Fakultäten > Fakultät für Ingenieurwissenschaften > Lehrstuhl Werkstoffverfahrenstechnik |
| Titel an der UBT entstanden: | Nein |
| Themengebiete aus DDC: | 500 Naturwissenschaften und Mathematik > 540 Chemie 600 Technik, Medizin, angewandte Wissenschaften > 620 Ingenieurwissenschaften |
| Eingestellt am: | 23 Apr 2021 08:31 |
| Letzte Änderung: | 28 Aug 2023 06:08 |
| URI: | https://eref.uni-bayreuth.de/id/eprint/64902 |