Site-specific synergy by heteronuclear microenvironment atomic editing for oxygen reduction reaction

Although iron-nitrogen-carbon catalysts are appealing for use in the oxygen reduction reaction, achieving high activity and a long lifetime remains a persistent challenge. This necessitates the precise modulation of the active sites' microenvironment. Herein, we present a microenvironment atomic editing strategy for accessing heteronuclear triatomic Fe and Co sites of Fe₁Co₂N₇O₁ supported on a nitrogen-doped carbon matrix (Fe₁Co₂/NC). Its performance is boosted by the orbital hybridization between Fe and Co atoms, which alters the d band centers to push the activity (half-wave potential of 0.94 V in alkaline and 0.88 V in acid conditions) and stability boundaries to a high level. The optimized metal-adsorbate interactions and strengthened metal - N bonding in Fe₁Co₂N₇O₁ are responsible for the competitive activity and stability. Furthermore, rechargeable and flexible quasi-solid-state zinc-air batteries using this catalyst achieve high power density (282.7 mW cm^-2 and 95.8 mW cm^-2) and high operational stability, and are therefore more energy-efficient than commercial catalysts. Our findings underscore the importance of atomic editing for designing low-nuclearity catalysts.