<i>In Situ</i> Manipulation of Surface Spin Configurations for Enhanced Performance in Oxygen Evolution Reactions.

Zhong, Chao; Zhou, Wenda; Luo, Xingfang; Li, Tingfeng; Huang, Fujin; Hu, Jiayong; Jiang, Zhenzhen; Hu, Ce et al. · Nano Lett · 2025

basic_science · Level V

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Abstract

<i>In situ</i> studies of the relationship between surface spin configurations and spin-related electrocatalytic reactions are crucial for understanding how magnetic catalysts enhance oxygen evolution reaction (OER) performance under magnetic fields. In this work, 2D Fe<sub>7</sub>Se<sub>8</sub> nanosheets with rich surface spin configurations are synthesized via chemical vapor deposition. <i>In situ</i> magnetic force microscopy and Raman spectroscopy reveal that a 200 mT magnetic field eliminates spin-disordered domain walls, forming a spin-ordered single-domain structure, which lowers the OER energy barrier, as confirmed by theoretical calculations. Electrochemical tests show that under a 200 mT magnetic field, the OER overpotential of multidomain Fe<sub>7</sub>Se<sub>8</sub> nanosheets at 10 mA cm<sup>-2</sup> decreases from 346 mV to 259 mV, while the magnetic field has minimal effect on single-domain nanosheets. These findings highlight the critical role of spin configurations in enhancing electrocatalytic performance, offering new insights into the design of magnetic catalysts for industrial applications.