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 PVC 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. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.