Axial Oxygen-Bridged Dual-Atom Sites Break the Activity–Stability Trade-Off in Oxygen Reduction Electrocatalysis

A pivotal challenge in advancing iron–nitrogen–carbon (Fe–N–C) catalysts for the oxygen reduction reaction (ORR) is their inherent activity–stability trade-off, which originates from the conflicting requirements of strong Fe–N bonding and optimal intermediate adsorption on the Fe active sites. Guided by first-principles screening, we herein report that constructing an axial Fe–O–Co bridge within a bilayer M–N–C architecture concurrently addresses the optimization of intermediate adsorption energetics and dynamic Fe–N bond stability. The competitive adsorption from axial oxygen alleviates the issue of overstrong intermediate adsorption on the Fe site toward accelerated *OH desorption and boosted ORR kinetics. Simultaneously, the axial CoN 4 –O ligand serves as an electronic buffer to dynamically compensate for adsorption-induced electronic polarization, thereby stabilizing Fe–N bonds and suppressing iron leaching during electrocatalysis. As a proof of concept, the FeCo dual-atom catalyst featuring an FeN 4 –O–CoN 4 configuration achieves a half-wave potential of 0.93 V in alkaline media, with only 8 mV decay after 140 000 cycles, far outperforming the Fe–N–C counterpart (53 mV decay). It maintains remarkable performance even in the highly challenging acidic electrolyte, delivering a peak power density of 1.12 W cm –2 and nearly 80% power density retention after 30 000 cycles. This study opens up a new avenue to break the activity–stability dilemma for M–N–C catalysts, advancing their practical deployment in fuel cells.