3D Edge-Enriched Fe3C@C Nanocrystals with a Core-Shell Structure Grown on Reduced Graphene Oxide Networks for Efficient Oxygen Reduction Reaction

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 Fe3C@C nanocrystals with a core-shell structure grown on reduced graphene oxide (rGO) networks (Fe3C@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 Fe3C@C nanocrystals, leading to a large surface area of 263m(2)g(-1) and superstable hybrid structure. The unique structural design of the Fe3C@C/rGO hybrid enables fast mass transport and a substantial number of exposed active edge sites for electrocatalytic reaction. The Fe3C@C/rGO hybrid exhibits excellent ORR catalytic activity, with a high positive onset potential close to 1.0V, a Tafel slope of 65mVdec(-1), and excellent durability with only about 8% current density decay at 0.8V after 20000s continuous operation, which is superior to that of commercial Pt/C catalyst in an alkaline electrolyte.