Electric-Field-Induced Spin-State Reconstruction of Atomically Dispersed Fe Sites at a Ferroelectric Interface

Dynamic spin-state modulation of atomically dispersed metal sites offers a promising route to optimize catalytic reactions, yet most strategies rely on static coordination structures fixed during synthesis. Here, we report electric-field-induced spin-state reconstruction of atomically dispersed Fe sites anchored at a ferroelectric Ni(DPA)2 interface. Fe sites were introduced by controlled Fe(III)-mediated etching and stabilized through interfacial Fe-O/Fe-N coordination. Density functional theory calculations reveal that electric-field-enhanced ferroelectric polarization drives asymmetric charge redistribution at the interface, promotes electron transfer to Fe centers, and weakens the local coordination field by transforming Fe from a planar four-coordinate geometry toward an unsaturated three-coordinate configuration. Spin-projected density of states and magnetic measurements indicate that a substantial fraction of Fe(III) centers is converted into higher-spin states. Benefiting from high-spin Fe sites and improved interfacial charge transfer, Fe-Ni(DPA)2 delivers efficient oxygen evolution activity. This work establishes ferroelectric interfaces as field-responsive platforms for dynamic spin engineering.