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

Abstract

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 Fe 3 C@C nanocrystals with a core–shell structure grown on reduced graphene oxide (rGO) networks (Fe 3 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 Fe 3 C@C nanocrystals, leading to a large surface area of 263 m 2 g −1 and superstable hybrid structure. The unique structural design of the Fe 3 C@C/rGO hybrid enables fast mass transport and a substantial number of exposed active edge sites for electrocatalytic reaction. The Fe 3 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.