3D Edge-Enriched Fe3 C@C Nanocrystals with a Core-Shell Structure Grown on Reduced Graphene Oxide Networks for Efficient Oxygen Reduction Reaction.

Abstract

The design of highly active, stable, and low-cost oxygen reduction reaction (ORR) electrocatalysts to replace platinum-based materials is crucial to the development of renewable energy technologies. Herein, novel 3D edge-enriched Fe3 C@C nanocrystals with a core-shell structure grown on reduced graphene oxide (rGO) networks (Fe3 C@C/rGO) are reported as highly efficient and stable electrocatalysts for the ORR. The rGO nanosheets act as a host and provide vital support for local growth of edge-enriched Fe3 C@C nanocrystals, leading to a large surface area of 263 m2 g-1 and superstable hybrid structure. The unique structural design of the Fe3 C@C/rGO hybrid enables fast mass transport and a substantial number of exposed active edge sites for electrocatalytic reaction. The Fe3 C@C/rGO hybrid exhibits excellent ORR catalytic activity, with a high positive onset potential close to 1.0 V, a Tafel slope of 65 mV dec-1 , and excellent durability with only about 8 % current density decay at 0.8 V after 20 000 s continuous operation, which is superior to that of commercial Pt/C catalyst in an alkaline electrolyte.