Mesoporous textured Fe-N-C electrocatalysts as highly efficient cathodes for proton exchange membrane fuel cells

• DOI: 10.1016/j.jpowsour.2021.230819
• Publication Date: 2021-11-28T09:45:58Z
• Authors: Srinu Akula; Marek Mooste; Barr Zulevi; Sam McKinney; Arvo Kikas; Helle-Mai Piirsoo; Mihkel Rähn; Aile Tamm; Vambola Kisand; Alexey Serov; Erin B. Creel; David A. Cullen; Kenneth C. Neyerlin; Hao Wang; Madeleine Odgaard; Tatyana Reshetenko; Kaido Tammeveski
• Keywords: Overpotential; Carbon fibers

Abstract A new platinum group metal (PGM)-free proton exchange membrane fuel cell (PEMFC) cathode catalyst materials, synthesized using the VariPore™ method by Pajarito Powder, LLC, are characterized for their structure and activity. The physico-chemical analysis of the iron-nitrogen-carbon (Fe-N-C) electrocatalysts show mesoporous carbon material effectively doped with iron and nitrogen. The materials have an average pore size of 7–8 nm and high specific surface area. The Fe-N-C catalysts exhibit good oxygen reduction reaction (ORR) activity in 0.5 M H2SO4 electrolyte with high half-wave potential and sustainable electrochemical stability over 10,000 repeated potential cycles with insignificant losses in their activities. As cathode catalysts in a PEMFC, the Fe-N-C materials deliver remarkably good fuel cell performance at low overpotential approaching that of the commercial Pt catalyst. The high ORR electrocatalytic activity of these Fe-N-C catalysts is credited to the synergy between nitrogen-moieties, specifically pyrrolic-N, pyridinic-N, and graphitic-N, and iron in addition to the high mesoporosity that facilitate an effective reaction path in boosting the electrocatalytic activity and stability.