Melamine-sponge-derived non-precious fuel cell electrocatalyst with hierarchical pores and tunable nitrogen chemical states for exceptional oxygen reduction reaction activity

Developing economic and highly active non-precious metal electrocatalysts for oxygen reduction reaction (ORR) is critical for the development of low-temperature fuel cells. We report here a novel non-precious Fe-N/C electrocatalyst with exceptional ORR electrocatalysis derived from melamine sponges with three-dimensional macroporous framework. The melamine sponge serves as an ideal carbon precursor for Fe-N/C catalyst, showing an order of magnitude improvement in microporous surface area hosting ORR active sites upon NH3 pyrolysis, hierarchical macro-/meso-pores for favorable mass transport and high pyridinic nitrogen content for strong surface basicity. These structural characteristics lead to exceptional ORR activity on the Fe-N/C electrocatalyst, demonstrating a half-wave potential of 0.902 V/RHE and mass activity of 15.0 A/g at 0.9 V/RHE in alkaline solution and markedly outperforming commercial Pt/C and most non-precious metal catalysts reported to date.