A graphene-based electrocatalyst co-doped with nitrogen and cobalt for oxygen reduction reaction

The development of low cost, active and stable non-precious metal (Co-N/C) catalysts to replace commercial Pt-based catalysts for oxygen reduction reaction (ORR) is a hot topic to this day. In this work, we have synthesized a new graphene-based catalyst (Co-N/C-A) doped by cobalt and nitrogen atoms with high contents of pyridinic- and pyrrolic-nitrogen (planar nitrogen), which exhibits ORR electrocatalytic activity with onset and peak potentials of 0.035 and −0.082 V (versus Hg/HgO) in 0.1 mol l−1 KOH solution, respectively. Besides, it has much higher stability and tolerance to methanol compared to the commercial Pt/C catalyst. The overall electron transfer number is calculated to be about 3.8. The transition-metal (Co) in the precursor can promote the formation of active sites during pyrolysis process and the followed acid-treatment may effectively expose the active sites on the surface of the catalyst, helping to enhance the ORR activity. It can be also proposed that pyridinic- and pyrrolic-nitrogen groups may play a key role in the ORR process and serve as the ORR active centers.