Facile strategy to synthesize hierarchical porous carbon encapsulated Fe/Fe3C nanocomposites toward efficient oxygen reduction reaction

Abstract

The design of a scale, high-efficiency and low-cost strategy to prepare high performance Fe-N-C oxygen reduction reaction (ORR) catalyst is crucial to driving commercial application of fuel cells. Herein, this work has reported a facile and scale solid-state synthesis approach for hierarchical porous Fe-N-C oxygen reduction catalyst enriched with graphite carbon layer encapsulated Fe/Fe3C nanoparticles and Fe-Nx sites nanocomposites, in which m-phenylenediamine was employed as precursor with melamine as etch agent in the case of FeCl3. Benefiting from high surface area, multiscale porous structure, and the synergistic effect between Fe/Fe3C nanoparticles and Fe-Nx sites, the resulting optimal electrocatalyst (Fe-mela-mPD-N-C) display distinguished oxygen reaction activity with half-wave potential of 0.86 V and kinetic current densities(Jk) up to 7.08 mA·cm−2 at 0.85 V in 0.1 M KOH, which is 50 mV higher than and 4.3 times as large as those of the commercial Pt/C, respectively; furthermore, it yields a low yield of H2O2 % (<5 %), 4-electron transfer pathway and good stability.