Atomically dispersed dual-metal with two-N-bridged FeCu-N6 sites for efficient oxygen reduction

Abstract

The sluggish reaction kinetics of oxygen reduction reactions (ORR), combined with a long-standing dependence on expensive and unstable platinum-based catalysts, has significantly hindered the progress of sustainable energy solutions. Here, we have developed an atomically dispersed bimetallic FeCu-loaded N-doped porous carbon (Fe1Cu1-NC) catalyst for remarkable ORR efficiency. X-ray absorption fine structure (XAFS) analysis accurately determines that the coordination state of atomically dispersed Fe-Cu sites is a two-N-bridged with N6 ligand. Fe1Cu1-NC has demonstrated superior ORR performance in alkaline environments when compared to commercial Pt/C catalysts. Notably, Fe1Cu1-NC exhibits a higher power density and specific capacity than Pt/C in zinc-air batteries. Density functional theory (DFT) calculations further confirm that the improved performance is due to the combined action of Cu and Fe single atoms, which results in a negative shift of the d-band center energy of Fe and facilitates activation of ORR intermediates.