Nanocluster‐Assisted OH Ligand Modification Optimizes Activity and Stability of Fe‐N‐C Catalysts

ABSTRACT Achieving high activity and durability in platinum‐metal‐free electrocatalysts remains a challenge for proton‐exchange membrane fuel cells. Fe/N‐C catalysts are alternatives to platinum‐based catalysts, but their performance is limited by the instability of Fe‐N x moieties under harsh operating conditions and site deactivation via uncontrolled ligand dynamics. Herein, we report a nanocluster‐assisted ligand‐anchoring strategy that establishes electronic coupling between Fe‐N x sites and adjacent Fe nanoclusters, which serve as auxiliary anchors to stabilize OH ligands on atomic Fe centers. Morphological characterization and density‐functional‐theory calculations reveal that charge redistribution between the single‐atom site and neighboring clusters tailors the electronic environment of the Fe‐N x reaction center. Ab initio molecular dynamics simulations confirm the dynamic stability of this cluster‐single‐atom motif with OH‐ligand modification under operating conditions. In situ Raman spectroscopy shows optimized evolution of oxygenated intermediates. The synergistic Fe single‐atom and nanocluster (Fe SA+NC ‐NC) catalyst exhibits a half‐wave potential of 0.92 V, a kinetic current density of 183.57 mA cm −2 at 0.85 V, and retains 95% of its initial activity after 300 h of operation. The zinc‐air battery delivers a peak power density of 154 mW cm −2 . This work presents a new paradigm for designing single‐atom catalysts by engineering the local coordination environment to overcome activity‐stability trade‐offs.