Details

Autor(en) / Beteiligte

• Casalongue, Hernan Sanchez
• Kaya, Sarp
• Viswanathan, Venkatasubramanian
• Miller, Daniel J.
• Friebel, Daniel
• Hansen, Heine A.
• Nørskov, Jens K.
• Nilsson, Anders
• Ogasawara, Hirohito

Titel

Direct observation of the oxygenated species during oxygen reduction on a platinum fuel cell cathode

Ist Teil von

• Nature communications, 2013-12, Vol.4 (1), p.2817, Article 2817

Ort / Verlag

London: Nature Publishing Group UK

Erscheinungsjahr

2013

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The performance of polymer electrolyte membrane fuel cells is limited by the reduction at the cathode of various oxygenated intermediates in the four-electron pathway of the oxygen reduction reaction. Here we use ambient pressure X-ray photoelectron spectroscopy, and directly probe the correlation between the adsorbed species on the surface and the electrochemical potential. We demonstrate that, during the oxygen reduction reaction, hydroxyl intermediates on the cathode surface occur in several configurations with significantly different structures and reactivities. In particular, we find that near the open-circuit potential, non-hydrated hydroxyl is the dominant surface species. On the basis of density functional theory calculations, we show that the removal of hydration enhances the reactivity of oxygen species. Tuning the hydration of hydroxyl near the triple phase boundary will be crucial for designing more active fuel cell cathodes. Understanding the oxygen reduction reaction at fuel cell cathodes requires information on adsorbed oxygenated species. Sanchez Casalongue et al . report in situ identification of oxygenated intermediates at cathodes and establish a correlation between the cathode potential and the surface speciation.