Iron and nitrogen co-doped hierarchical porous graphitic carbon for a high-efficiency oxygen reduction reaction in a wide range of pH

Abstract

Developing an efficient, easy-to-fabricate and applicable noble-metal-free catalyst for the oxygen reduction reaction (ORR) is extremely necessary for fuel cells. In this context, by pyrolyzing a nontoxic and low-cost iron-coordinated polydopamine polymer (Fe–PDA-30, 30 represents the polymerization time) precursor at 800 °C, a template-free oxygen reduction reaction (ORR) catalyst iron and nitrogen co-doped hierarchical porous graphitic carbon (Fe,N/PGC-30) was obtained. The obtained catalyst Fe,N/PGC-30, first reported here, manifests outstanding oxygen reduction activity in a wide range of pH. It is worth nothing that the catalyst exhibits remarkable ORR activity with a more positive half-wave potential of 15 mV than that of the commercial Pt/C catalyst under alkaline conditions. Additionally, the activity of the catalyst is comparable to that of commercial Pt/C under neutral and acidic conditions with almost a 4e⁻ reaction process and very low H₂O₂ yield. This catalyst provides an exciting direction for non-precious metal electrocatalysts with excellent oxygen reduction activity in a wide range of pH. These favorable results demonstrate that the catalyst Fe,N/PGC-30 can serve as a highly efficient and stable ORR catalyst for practical fuel cell applications.