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 Delta E (= 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. (C) 2019 Elsevier Ltd. All rights reserved.