Dynamic Spin Governing Asymmetric Coordination Fields in Trimetallic Single‐Atom Catalysts for Optimal Oxygen Reduction

Abstract Single‐atom catalysts demonstrate theoretically superior oxygen reduction reaction (ORR) kinetics, the limited dynamic adaptability, however, poses a giant challenge to meet the multi‐step proton‐coupled electron transfer (PCET). Herein, we propose a “ Dynamic Spin Engineering ” strategy for the rational design of tri‐metallic single‐atom catalysts (FeZnTM‐TACs) featuring asymmetric coordination fields (FeN 4 ZnN 3 TMN 4 ). Leveraging electron synergy and spatial functional decoupling among heterometallic sites, the optimized FeZnMn‐TACs exhibit exceptional ORR performance ( E 1/2 = 0.93 V versus RHE) and ultra‐long stability (Δ E 1/2 = 24 mV after 90,000 cycles). Through operando X‐ray absorption fine structure and spin‐polarized density functional theory, we unveil the scalability of a ternary synergy encompassing dynamic reconstruction, charge compensation and spin‐state transition, clarifying the roles of electron donors at the ZnN 3 sites and proton supply at MnN 4 sites. Dynamic FeN x C y evolution triggers a spin‐state transition from medium spin (MS = 1.5) to low spin (LS = 1.0), accompanied by the d xz / d yz orbital occupancy degree from 50% to 100%. As a consequence, we synergize the dual optimization of *OOH formation and *OH desorption in PCET. Moreover, our work atomically deciphers the spin redistribution mechanism driven by dynamic reconstruction, establishing a new paradigm for designing self‐adaptive electrocatalysts that ultimately unify ultrahigh activity with operational stability.