Low content of Fe₃C anchored on Fe,N,S-codoped graphene-like carbon as bifunctional electrocatalyst for oxygen reduction and oxygen evolution reactions

A novel kind of non-precious metal Fe₃C@Fe,N,S-GCM nanocomposite with very low metal content is obtained by a simple one-pot pyrolysis method using abundent, low cost and environmental friendly resouces. In the Fe₃C@Fe,N,S-GCM nanocomposite, the Fe₃C nanoparticles are uniformly anchored on the Fe,N,S-codoped graphene-like carbonaceous matrix. Synergetic multiple electrocatalytic active sites of Fe₃C, Fe-N_x and N,S-co-doped carbon are identified for Fe₃C@Fe,N,S-GCM. The Fe₃C@Fe,N,S-GCM nanocomposite also possesses the high BET surface area and meso/macropore volume from the hierarchical porous superstructure, which may benefit the storing and transport of electrolyte ions. Attributed to the rational content and microstructure, the Fe₃C@Fe,N,S-GCM presents a high bifunctional electrocatalytic activity for both oxygen reduction reaction (ORR)and oxygen evolution reaction (OER)with the ΔE (= E_OER - E_ORR)of only 0.750 V. The bifunctional electrocatalytic activity is not only better than the commercial precious metal couples of RuO₂ (OER)and Pt/C (ORR), but also represents the superiority among the non-precious metal ferrous bifunctional electrocatalysts.