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 H2O by using InOperando X-ray Absorption Spectroscopy

Ist Teil von

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

Ort / Verlag

Weinheim: Wiley Subscription Services, Inc

Erscheinungsjahr

2015

Link zum Volltext

Quelle

Wiley Online Library

Beschreibungen/Notizen

• Application of the [Delta]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 H2), 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 7mgmin-1) with CO to the anode feed reduces the amount of adsorbed phosphate and, thereby, increases the activity.