Role of magnetic exchange in catalytic spin effects: insights from nitrite reduction on Co3O4

Abstract

Spin has emerged as a potent tool for enhancing catalytic performance across various reactions and catalysts. While current research on “spin effects” primarily focuses on the interaction between the spin moments of active sites and adsorbates, the significance of magnetic exchange among active sites is often overlooked. Herein, we unveil the critical impact of magnetic coupling between active sites on electrocatalytic performance through a detailed theoretical investigation of the nitrite reduction reaction (NO₃RR) on Co₃O₄ as an example. It is found that while the spin moments of active sites significantly affect the adsorption energy of *NO₃, the magnetic coupling between active sites plays a key role in the formation of *NO₃H and in determining the limiting potential. Based on the findings, we have successfully revealed the origin of the excellent NO₃RR performance of low-spin (LS) doped Co₃O₄ from the perspective of spin effects, that is, the spin flip enabled by LS doping induces localized antiferromagnetic (AFM) coupling and facilitates *NO₃H adsorption, which remarkably decreases the Gibbs free energy change and improves the activity. Such a result is consistent with experimental studies and may provide new insights into understanding the spin related catalysis mechanism. Our findings specifically illustrate the critical role of magnetic coupling in catalysis, providing an insightful understanding of the spin effect mechanism and offering a novel strategy for designing high-performance catalysts.