Water Oxidation Promoted by Proximity-Induced Magnetism under Dzyaloshinskii–Moriya Interaction

Spin polarization governs the kinetics of multielectron water oxidation, yet benchmark catalysts like IrO2 lack intrinsic ferromagnetism at ambient temperature, precluding spin control. Here, we exploit the interfacial Dzyaloshinskii–Moriya interaction (DMI) in Co/IrO2 bilayers to induce spin-polarized states in the surface IrO2. This DMI-driven spin polarization boosts intrinsic oxygen evolution reaction activity by 1 order of magnitude, achieving a turnover frequency of 4.17 s–1 at 300 mV overpotential. Ferromagnetic resonance spectroscopy quantifies strong interfacial spin polarization via a 100% increase in the Gilbert damping. Spin-polarized DFT shows that DMI stabilizes a ferromagnetic ground state in IrO2 and reveals that spin ordering alters the adsorption configurations and lowers reaction barriers for *OH dehydrogenation and O–O coupling. Inserting a Cu spacer eliminates DMI, quenching both magnetism and catalytic enhancement. Our results establish interfacial DMI as a general strategy to activate hidden spin states in nonmagnetic oxides, offering a new route to surpass the activity limits in water-oxidation catalysis.