Magnetic field mediated oxygen radical mechanism for enhanced water oxidation

The spin-sensitive nature of redox reactions in energy conversion systems, such as the oxygen evolution reaction (OER), has attracted increasing attention due to its potential for enhancing catalytic efficiency. Magnetic fields (MFs) have been proposed to enhance OER performance by influencing the spin states of oxygen intermediates. However, prior study has predominantly focused on MF effects mediated by the intrinsic magnetic properties of electrocatalysts or magnetohydrodynamics. In this work, we report a universal enhancement in OER activity, achieving over 150 % increase in current density under a 200 mT MF across diamagnetic, paramagnetic and magnetic electrocatalysts in 1 M KOH. Through systematic investigation of MF orientation and strength, pH, applied potentials, and the use of benzoquinone radical scavenger, we demonstrate that MF-driven performance improvements arise from direct modulation of oxygen radical spin states. Specifically, MFs promote the formation of spin-triplet oxygen intermediates (↑O–O↑), a critical step for O–O bond formation, independent of the catalyst’s intrinsic magnetism. However, the local magnetic environment near the catalyst surface, governed by its magnetic properties, indirectly influences radical spin dynamics by alternating the effective field experienced by intermediates. These findings redefine the role of spin manipulation in electrocatalysis, advancing understanding of MF-driven spin effects in redox reactions.