Stabilizing FeNx sites and boosting oxygen reduction via interfacial proton pumps created by phosphorus doping

Atomic phosphorus doping creates Lewis-base “proton pump” sites that coordinate interfacial water, dramatically lower the water dissociation barrier (0.87 → 0.05 eV). • This targeted acceleration of the rate-determining step boosts the peak power density of Zn–air batteries to 183 mW·cm -2 . • Increases the open-circuit voltage and broadens the operational voltage window. Development of Fe-NC catalysts is fundamentally challenged by their performance decay in acidic media, originating from insufficient proton-coupled electron transfer kinetics and irreversible iron leaching. Herein, we transcend conventional electronic structure modulation by introducing a local interfacial pH tailoring strategy via atomic phosphorus doping. The incorporated P species, serving as Lewis-base sites, function as efficient “proton pumps”. They actively coordinate with interfacial water molecules via lone-pair electrons, which not only enhances H 2 O adsorption but also significantly weakens the O H bond, drastically reducing the water dissociation energy from 0.87 to 0.05 eV. This triggered water activation creates a unique proton-enriched interfacial microenvironment at the catalyst interface while maintaining an alkaline bulk electrolyte, a phenomenon directly visualized by in-situ Raman spectroscopy. The accelerated local proton supply promotes the rate-determining *OOH formation step, while the modulated electronic structure concurrently stabilizes the Fe-Nₓ centers, suppressing Fe dissolution to a remarkably low level. When deployed in a Zn-air battery, this synergistic mechanism enables the Fe-P-NC cathode to achieve a record-high power density of 183 mW·cm −2 . This work underscores the profound potential of active interfacial microenvironment engineering in breaking the activity–stability trade-off for advanced electrocatalysis.