Single-atom catalysts (SACs) have become one of the most considered research directions today, owing to their maximum atom utilization and simple structures, to investigate structure-activity relationships. In the field of non-precious-metal electrocatalysts, atomically dispersed Fe-N₄ active sites have been proven to possess the best oxygen reduction activity. Yet the majority of preparation methods remains complex and costly with unsatisfying controllability. Herein, we have designed a surface-grafting strategy to directly synthesize an atomically dispersed Fe-N₄/C electrocatalyst applied to the oxygen reduction reaction (ORR). Through an esterification process in organic solution, metal-containing precursors were anchored on the surface of carbon substrates. The covalent bonding effect could suppress the formation of aggregated particles during heat treatment. Melamine was further introduced as both a cost-effective nitrogen resource and blocking agent retarding the migration of metal atoms. The optimized catalyst has proven to have abundant atomically dispersed Fe-N₄ active sites with enhanced ORR catalytic performance in acid condition. This method has provided new feasible ideas for the synthesis of SACs.

FullText for HTML:https://doi.org/10.1007/s12274-020-2768-y