Résumé
Proton exchange membrane fuel cell (PEMFC)s are an excellent energy conversion device for wide application of hydrogen, especially for portable or transportation applications. To reduce the total cost of these devices, non-precious-metal catalysts (NPMCs) have shown promises in replacing platinum-based catalysts. Among NPMCs, iron-nitrogen-carbon (Fe-N-C) catalysts subclass are the most mature. These catalysts are based on nitrogen (N) coordinated iron (Fe) ions embedded in a carbon (C) matrix acting as catalytically active centers. Numerous studies have focused on promoting their catalytic performance towards the oxygen reduction reaction (ORR). Nevertheless, such materials remain less performant than carbon-supported platinum nanoparticles (Pt/C), leading to ca. 3-10 times thicker cathodes, and associated mass transport limitations.Carbon aerogels are ideal candidates to synthesize Fe-N-C catalysts with tuneable mass transport properties thanks to their tridimensional open texture, tailored pore size distribution from micro to macropores and their good electrical conductivity. Herein, we show the promises of Fe-N-C aerogels synthesized a “one pot” sol-gel method comprising formation of a Fe-doped resorcinol (R)-formaldehyde (F)-melamine (M) hydrogel, and followed by carbon dioxide (CO2) supercritical drying, and high temperature pyrolysis under N2 and NH3 atmosphere. By introducing ligands in the synthesis mixture, we modified the chemical environment of the Fe precursor. The resulting changes in morphology, ORR activity and mass transport properties are investigated a rotating disk electrode (RDE) set-up and a PEMFC device.