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Science 3 April 2009:
Vol. 324. no. 5923, pp. 71 - 74
DOI: 10.1126/science.1170051
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Reports

Iron-Based Catalysts with Improved Oxygen Reduction Activity in Polymer Electrolyte Fuel Cells

Michel Lefèvre,* Eric Proietti,* Frédéric Jaouen, Jean-Pol Dodelet{dagger}

Iron-based catalysts for the oxygen-reduction reaction in polymer electrolyte membrane fuel cells have been poorly competitive with platinum catalysts, in part because they have a comparatively low number of active sites per unit volume. We produced microporous carbon–supported iron-based catalysts with active sites believed to contain iron cations coordinated by pyridinic nitrogen functionalities in the interstices of graphitic sheets within the micropores. We found that the greatest increase in site density was obtained when a mixture of carbon support, phenanthroline, and ferrous acetate was ball-milled and then pyrolyzed twice, first in argon, then in ammonia. The current density of a cathode made with the best iron-based electrocatalyst reported here can equal that of a platinum-based cathode with a loading of 0.4 milligram of platinum per square centimeter at a cell voltage of ≥0.9 volt.

Institut National de la Recherche Scientifique, Énergie, Matériaux et Télécommunication, Varennes, Québec J3X 1S2, Canada.

* These authors contributed equally to this work.

{dagger} To whom correspondence should be addressed. E-mail: dodelet{at}emt.inrs.ca

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Science. ISSN 0036-8075 (print), 1095-9203 (online)