Magneto–Photo Synergism Enhances Oxygen Evolution Reaction on Hollow NiCo ₂ O ₄ Microboxes

Abstract Magneto–photo coupling offers a promising strategy to enhance the oxygen evolution reaction (OER) for efficient energy conversion. Here, a synergistic approach that integrates an external magnetic field with visible‐light irradiation to regulate the electronic structure of hollow NiCo ₂ O ₄ microboxes is demonstrated. The unique hollow cubic architecture, assembled from 2D nanosheets, ensures abundant active sites and robust structural stability. Magnetic stimulation induces non‐collinear spin reorientation and enhanced spin polarization, increasing the electronic density of states near the Fermi level to facilitate charge transport and optimize intermediate adsorption. Concurrently, light irradiation generates photocarriers that accelerate charge separation and reaction kinetics. Benefiting from this synergy, the catalyst delivers a 204.4 mV reduction in overpotential at 10 mA·cm ⁻² and a 115.8 mV·dec ⁻¹ improvement in Tafel slope, demonstrating superior activity and long‐term stability. First‐principles calculations confirm that the cooperative effect of magnetic and light fields optimizes intermediate adsorption and reduces energy barriers, thereby accelerating OER kinetics. This study highlights the unique advantages of magneto–photo coupling in electrocatalysis and provides insights into designing responsive catalysts and advancing multi‐field coupling strategies for next‐generation electrochemical energy technologies.