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

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 drive 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/Fe 3 C nanoparticles and Fe-N x sites nanocomposites, in which m-phenylenediamine was employed as precursor with melamine as etch agent in the case of FeCl 3 . Benefiting from high surface area, multiscale porous structure, and the synergistic effect between Fe/Fe 3 C nanoparticles and Fe-N x 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( J k ) 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 H 2 O 2 % (<5%), 4-electron transfer pathway and good stability. A facile and scale solid-state synthesis approach has been proposed to prepare hierarchical porous Fe-N-C oxygen reduction catalyst enriched with graphite carbon layer encapsulated Fe/Fe 3 C nanoparticles and Fe-N x site nanocomposites. The optimal electrocatalyst (Fe-mela-mPD-N-C) display distinguished oxygen reaction activity with half-wave potential of 0.86 V in 0.1 M KOH, which is 50 mV higher than that of the commercial Pt/C catalyst. Furthermore, it yields a low yield of H 2 O 2 % (<5%), 4-electron transfer pathway and good stability. • Fe/Fe 3 C nanoparticles embedded in multiscale porous Fe-N-C electrocatalyst via a solid-state synthesis approach is prepared. • The introduction of melamine plays a crucial role in the formation of multiscale porous structure and highly active sites (Fe-N x and pyridinic N). • The as-prepared Fe-mela-mPD-N-C catalyst achieves higher ORR activity than commercial Pt/C in 0.1 M KOH.