Dual templated assisted fabrication of atomically dispersed Fe active sites on nitrogen-doped porous carbon for enhanced oxygen reduction reaction in Zn-air battery

Abstract

The embedding of iron single atom into nitrogen-doped carbon matrix (Fe-N-C) provides an alternative option to precious metal-based electrocatalysts for oxygen reduction reaction (ORR). Modulating the microenvironment around the central iron atom can substantially prompt the electrocatalytic activity. Herein we demonstrate the fabrication of single atomic iron sites embedded on nitrogen-doped porous carbon (SA-FeNC/NPC) through a dual-template strategy as efficient ORR electrocatalyst. The presence of defect-rich, highly dispersed Fe-N₄ active sites, coupled with extensive porosity and excellent conductivity, confer superior ORR performance in alkaline media, achieving a half-wave potential of 0.904 V, significantly surpassing commercial Pt/C electrocatalysts, while exhibiting good methanol tolerance and cycling stability. When applied to Zn-air battery, SA-FeNC/NPC-900 demonstrates a charging and discharging stability up to 120 h. Density functional theory (DFT) calculations reveal that the unique combination of carbon defect around single-iron atom sites, abundant pyridinic nitrogen, and the layered porous architecture significantly enhances the ORR activity.