Facile graphene quantum dot-anchoring strategy synthesis of single-atom iron-nitrogen electrocatalyst with enhanced ORR performance

Single-atom catalysts (SACs), especially atomically dispersed Fe-Nx-C based SACs, hold great promise to replace Pt-based electrocatalysts for oxygen-reduction reaction (ORR). Currently, synthesizing high-activity ORR electrocatalysts with atomically dispersed Fe-Nx site structures is still challenging due to their high surface free energy, which leads to easy migration and serious aggregation. Herein, we have designed a general graphene quantum dots (GQDs)-anchoring strategy to synthesize a single-iron-atom electrocatalyst (Fe-N-GQDs/PC) applied to ORR through calcining of N-GQDs-Fe3+ modified porous carbon (PC) and melamine. Experiments demonstrate the N-GQDs consist of abundant oxygenated groups, which could lead to complexing metal ions and thus facilitating the formation of SACs. Furthermore, the Fe-N-GQDs/PC electrocatalyst exhibits outstanding electrocatalytic ORR activity in 0.1 M KOH media with half-wave potentials of 0.84 versus 0.85 V for Pt/C. This strategy has opened up new feasible ideas to produce SACs for electrochemical energy devices.