Engineering Magnetic Heterostructures with Synergistic Regulation of Charge‐Transfer and Spin‐Ordering for Enhanced Water Oxidation

The design of heterojunctions offers a crucial solution for energy conversion and storage challenges, but current research predominantly focuses on charge transfer benefits, often neglecting spin attribute regulation despite the increasing recognition of spin-sensitivity in many chemical reactions. In this study, a novel magnetic heterostructure, CoFe₂O₄@CoFeMo₃O₈, is designed to simultaneously modulate charge and spin characteristics, and systematically elucidated their synergistic impact on the oxygen evolution reaction (OER). Experimental results and density functional theory calculations confirmed that the magnetic heterostructure exhibits both charge transfer and spin polarization. It is found that the charge-transfer behavior enhances conductivity and adsorption ability through band structure regulation. Meanwhile, magnetically polarized electrons promote triplet O₂ generation and accelerate electron transport via spin-selective pathways. Moreover, the heterostructure's effective response to external alternating magnetic fields further amplifies the spin-dependent effect and introduces a magnetothermal effect, locally heating the active sites through spin flip, thereby boosting catalytic activity. Consequently, the OER activity of the magnetic heterostructure is improved by 83.8 times at 1.5 V compared to its individual components. This magnetic heterojunction strategy presents a promising avenue for advanced catalysis through synergistic regulating of charge-transfer and spin-ordering.