Fe-N co-decorated hierarchically porous graphene as a highly efficient electrocatalyst for the oxygen reduction reaction

Fe-N co-decorated hierarchically porous graphene (FeN/G) was prepared by a facile one-step pyrolysis method. In the pyrolysis synthesis process, dicyandiamide was introduced as a nitrogen precursor and sacrificial templating agent, together with ferric nitrate utilized as an iron precursor, to aid in the formation of graphene nanosheets and their self-assembly into an interconnected porous framework. Consequently, the resultant FeN/G framework shows a relatively large specific surface area (401.1 m(2) g(-1)), hierarchically porous structure and abundant meso-/macropores. Such highly desired FeNC structures not only possess sufficient catalytically active sites for the oxygen reduction reaction (ORR) but also guarantee fast transfer of reactants and ions, which provides excellent catalytic activity with positive onset and half-wave potentials, large kinetic-limiting current density, and remarkable durability that is obviously better than the commercial Pt/C in alkaline medium.