Combined effects of transition metal nitrogen and graphene nanoribbon edge active sites on the oxygen reduction reaction catalytic performance of metal–N–carbon-based catalysts

Metal-nitrogen-carbon (metal-N-C)-based catalysts with optimized local and external structures have received considerable attention owing to their improved activity and stability for the oxygen reduction reaction (ORR) in fuel cells. Abundant well-defined active sites on catalysts effectively enhance ORR performances. Herein, the Fe/Co-nitrogen-carbon-graphene nanoribbons (Fe/Co-N-C-GNRs) hybrids were obtained through the <i>in situ</i> growth of Fe/zeolitic imidazolate framework-67 particles on the surface of graphene oxide nanoribbons. The Fe/Co-N-C-GNRs exhibit a high electrocatalytic activity for the ORR (onset and half-wave potentials of 0.95 V and 0.83 V, respectively) and high durability, which are superior to those of 20 wt% Pt/C, suggesting Fe/Co-N-C-GNRs provide Fe-N _<i>x</i> , Co-N _<i>x</i> , and FeCo-N _<i>x</i> and GNR edge active sites. The Fe/Co-N-C-GNRs are excellent functional electrocatalytic catalysts exhibiting significant potential for fuel cell, chlor-alkali industry and lithium-oxygen battery applications.