Facile preparation of Fe3C decorate three-dimensional N-doped porous carbon for efficient oxygen reduction reaction

Abstract

Novel Fe3C nanoparticles that decorate three-dimensional N-rich porous carbon (Fe3C@3DNC) catalysts were designed and synthesized by double templates assisted high-energy ball milling and subsequent high-temperature pyrolysis for the oxygen reduction reaction (ORR). NaCl and Na2SiO3 are used as the mixed template while Fe(NO3)3·9H2O and 2-Methylimidazole were used as the iron, nitrogen and carbon sources. The optimized Fe3C@3DNC catalyst (Fe3C@3DNC-1-900) had good ORR performance in alkaline medium, with an Eonest value of 0.968 V and E1/2 value of 0.861. In addition, the catalytic process exhibited selectivity–nearly four-electron transfer kinetics and possesses a lower Tafel slope compared to commercial Pt/C catalyst as well as good methanol tolerance. In addition, the Fe3C@3DNC-1-900 catalyst also had excellent ORR activity (E1/2 = 0.72 V) and long-term stability (the half-wave potential only occurs at 10 mV after 5000 cycles) in acidic media. The good catalytic performance of the Fe3C@3DNC-1-900 catalyst can be attributed to the 3D hierarchically porous structure and extremely high number of active sites around the porous carbon. The double template assisted high-energy ball milling strategy can be a promising and scalable method to prepare three-dimensional porous carbon-based composite materials for energy conversion and storage applications.