Performance of polyaniline-derived Fe-N-C catalysts for oxygen reduction reaction in alkaline electrolyte

Abstract

Without the presence of any precious metal, Fe-N-C materials derived from pyrolysis of polyaniline (PANI)/carbon/FeCl 3 mixtures are recognized as new catalysts for cathodic oxygen reduction reaction (ORR) in acidic electrolyte. How these Fe-N-C catalysts would perform in an alkaline electrolyte remains yet unknown. Reported here are assessments of the ORR performance of two Fe-N-C catalysts (Fe content: 3.4% and 5.9%) in auqeous KOH by rotating disk electrode methods. Both Fe-N-C catalysts were found much more active than those metal-free N-doped carbon materials in literature. Moreover, the ORR onset and half-wave potentials over both Fe-N-C catalysts were respectively within 60 and 40 mV from those delivered by conventional Pt/C catalyst and both Fe-N-C catalysts even showed much superior catalytic stability in chronoamperometric measurement. ORR on the present Fe-N-C catalysts proceeded predominantly via a four-electron transfer mechanism. This work would shed a light on Fe-N-C materials for ORR catalysis in alkaline fuel cells. The onset and half-wave potentials of PANI-derived Fe-N-C catalysts are found close to conventional Pt/C catalyst for cathodic ORR in alkaline electrolyte; the Fe-N-C catalysts show even significantly higher stabilities.