Spin-polarized oxygen evolution catalysis enabled by a honeycomb quantum magnet

The spin state of electrocatalysts has recently emerged as a critical factor governing the kinetics of the oxygen evolution reaction (OER). Here, we demonstrate that intrinsic spin polarization, enabled by magnetic anisotropy in frustrated quantum magnets, can drive highly efficient OER without external magnetic fields. Using the honeycomb cobaltate series Na2Co2–xNixTeO6 (0 ≤ x ≤ 1.0), we systematically modulate spin interactions via chemical substitution while preserving crystal symmetry. Experimental and theoretical analyses show that the parent compound Na2Co2TeO6, a Kitaev-type frustrated antiferromagnet, exhibits a spin-polarized electronic structure in its ground state, which correlates with markedly superior OER performance. Electrochemical measurements reveal a monotonic decline in catalytic activity per active Co atoms with increasing Ni content, with NCTO exhibiting the lowest overpotential of 290 mV, lowest Tafel slope of 40 mV/dev, and highest turnover frequency per active site. Notably, all compositions display enhanced stability potentially attributed to lattice contraction driven by spin–lattice coupling inherent to frustrated magnets. This study identifies quantum magnets as a promising new class of catalytic materials, opening a paradigm shift in spin-based electrocatalyst design.