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Roth, Christina ; Benker, Nathalie ; Buhrmester, Thorsten ; Mazurek, Marian ; Loster, Matthias ; Fuess, Hartmut ; Koningsberger, Diederik C. ; Ramaker, David E.:
Determination of O[H] and CO Coverage and Adsorption Sites on PtRu Electrodes in an Operating PEM Fuel Cell.
In: Journal of the American Chemical Society.
Bd. 127
(2005)
Heft 42
.
- S. 14607-14615.
ISSN 1520-5126
DOI: https://doi.org/10.1021/ja050139f
Abstract
A special in situ PEM fuel cell has been developed to allow X-ray absorption measurements during real fuel cell operation. Variations in both the coverage of OH (OH indicates O and/or OH) and CO (applying a novel ΔμL3 = μL3(V) − μL3(ref) difference technique), as well as in the geometric (EXAFS) and electronic (atomic XAFS) structure of the anode catalyst, are monitored as a function of the current. In hydrogen, the NPt-Ru coordination number increases much slower than the NPt-Pt with increasing current, indicating a more reluctant reduction of the surface Pt atoms near the hydrous Ru oxide islands. In methanol, both OH and CO adsorption are separately visible with the {\ensuremath{\Delta}}{\ensuremath{\mu}} technique and reveal a drop in CO and an increase in OH coverage in the range of 65?90 mA/cm2. With increasing OH coverage, the Pt?O coordination number and the AXAFS intensity increase. The data allow the direct observation of the preignition and ignition regions for OH formation and CO oxidation, during the methanol fuel cell operation. It can be concluded that both a bifunctional mechanism and an electronic ligand effect are active in CO oxidation from a PtRu surface in a PEM fuel cell.
Weitere Angaben
| Publikationsform: | Artikel in einer Zeitschrift |
|---|---|
| Begutachteter Beitrag: | Ja |
| 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 07:52 |
| Letzte Änderung: | 05 Apr 2022 06:49 |
| URI: | https://eref.uni-bayreuth.de/id/eprint/64891 |