Synergistic Strong-Weak Adsorption Coupling in the FeN₆–CoN₄Dual-Site Modulates Oxygen Reduction Pathways via Oxygen Adsorbate Evolution-to-Dissociation Transition

Atomically dispersed non-noble metal–nitrogen-carbon electrocatalysts could derive a four-electron oxygen reduction reaction (ORR) described via a typical adsorbate evolution mechanism (AEM), but their kinetics are limited by the linear scaling relationship (LSR) between the *OOH and *OH. Herein, we reported heteronuclear dual-site FeN₆–CoN₄ materials obtained via integrating Fe³⁺ and Co²⁺ into pyrrole-functionalized g-C₃N₄ nanosheets. Such electrocatalysts broke the conventional LSR through a shifted oxygen dissociation mechanism (ODM: *O₂ → *O + *OH → 2 *OH). Density functional theory calculations confirmed the strongest and weakest adsorption strengths of key ORR intermediates in the CoN₄ and FeN₆ sites with a conventional AEM pathway. Under the synergistic effect of dual-site strong-weak adsorption, FeN₆–CoN₄ switched from ORR pathways to the ODM observed via in situ infrared spectroscopy for the rate-determining step (*O₂ → *O + *OH) with the decreased overpotentials of 0.41 V (FeN₆) and 0.50 V (CoN₄), enhancing intrinsic ORR kinetics. A Zn–air battery based on FeN₆–CoN₄ demonstrated an open-circuit voltage of 1.65 V approaching the theoretical 1.68 V, high-power density of 314 mW cm^–2, and durable discharge at 500 mA cm^–2. This work provides fundamental insights into dual-site synergy for regulating ORR pathways, offering a strategy for designing efficient atomic catalysts.