Details

Autor(en) / Beteiligte

• Caldwell, Keegan M.
• Kaserer, Sebastian
• Roth, Christina
• Ramaker, David E.

Titel

Following Adsorbate Coverage on Anodes of High‐Temperature Polymer Electrolyte Membrane Fuel Cells in the Presence of CO and H 2 O by using In Operando X‐ray Absorption Spectroscopy

Ist Teil von

• ChemElectroChem, 2015-10, Vol.2 (10), p.1502-1509

Erscheinungsjahr

2015

Quelle

Wiley Blackwell Single Titles

Beschreibungen/Notizen

• Abstract Application of the Δ μ X‐ray absorption near‐edge spectroscopy analysis technique to a polybenzimidazole‐membrane‐based high‐temperature (170 °C) polymer electrolyte membrane fuel cell (PEMFC) under varying conditions reveals binding‐site details for H, CO, and biphosphate on a platinum nanoparticle anode surface. A synergistic interplay between CO and biphosphate adsorption is found, so that with increasing CO in the gas feed (below 3–4 % in H 2 ), an increased biphosphate coverage becomes visible, apparently because small amounts of adsorbed CO force more localization of the phosphate species, which is believed to be adsorbed on top of the existing H overlayer. Increasing the concentration of CO (well above 4 %) causes CO poisoning to takeover and dramatically decrease the activity, though, compared to low‐temperature PEMFCs, huge amounts of CO can still be tolerated. Adding small amounts of water (less than 7 mg min −1 ) with CO to the anode feed reduces the amount of adsorbed phosphate and, thereby, increases the activity.