"Double Role of Water in the Fuel Cell Oxygen Reduction Reaction"

H. Ogasawara: L. A. Naslund, J. McNaughton, T. Anniyev and Anders Nilsson; ECS Transactions, 01/01/08.

Additional Authors: L. A. Naslund, J. McNaughton, T. Anniyev and Anders Nilsson

Abstract:

Water is present during the normal operating condition of polymer electrolyte membrane fuel cells (PEMFCs) and we have, through model experiments on a platinum surface using x-ray photoelectron spectroscopy, investigated its role in two different stages in the oxygen reduction reaction (ORR). We found that the activation of oxygen to the adsorbed atomic phase occurs readily in the dry region, but not in the humid region process. In this case, water is acting to inhibit the active sites on the catalyst. On the contrary, water is found to promote the reduction of adsorbed atomic oxygen in the formation of a water-hydroxyl surface complex.