Here we report an iron-acetate/phenanthroline/zeolitic-imidazolate-framework-derived electrocatalyst with increased volumetric activity and enhanced mass-transport properties. The zeolitic-imidazolate-framework serves as a microporous host for phenanthroline and ferrous acetate to form a catalyst precursor that is subsequently heat treated. A cathode made with the best electrocatalyst from this work, tested in H₂-O₂, has a power density of 0.75 W cm⁻² at 0.6 V, a meaningful voltage for polymer-electrolyte-membrane fuel cells operation, comparable with that of a commercial Pt-based cathode tested under identical conditions.

—Proietti et al.

The new research findings bolster the prospect of iron-based catalysts replacing platinum ones in the electrochemical reduction of oxygen, one of two reactions required in a fuel cell. Platinum is rare and very costly, whereas iron is the second most abundant metal on earth and is inexpensive.

Working at the Énergie Matériaux Télécommunications Research Centre in Varennes (Québec), INRS scientists are now focusing on the improvement of the long-term stability (at least 5,000 hours) of these new catalysts.

Resources

• Eric Proietti, Frédéric Jaouen, Michel Lefèvre, Nicholas Larouche, Juan Tian, Juan Herranz & Jean-Pol Dodelet (2011) Iron-based cathode catalyst with enhanced power density in polymer electrolyte membrane fuel cells. Nature Communications 2, 416 doi: 10.1038/ncomms1427