Bio‐Magnetically Tailored Spin Configurations in Ni‐Doped FeS Pre‐Catalysts for Alkaline Water Splitting

ABSTRACT Oxygen evolution reaction (OER) with spin‐forbidden transitions is a key bottleneck in efficient water splitting. Here, a magnetic field (MF)‐assisted microbial corrosion strategy is developed to construct bimetallic sulfide nanosheets with a tunable high‐spin (HS) state. Experimental and Theoretical calculations reveal that HS Ni doping enhances the structural stability of FeS and promotes the formation of active phases. As a result, the obtained NiS@FeS/HS catalyst exhibits excellent OER activity, requiring an overpotential of only 259 mV at 100 mA cm −2 . More importantly, the Ni‐S and Fe‐S/HS coordination makes the reconstructed Ni(Fe)OOH active phase retain the HS electronic structure during the OER process. The inherited HS state promotes spin‐polarized charge transfer and suppresses lattice‐oxygen participation, thereby enhancing the OER catalytic activity and structural stability. Furthermore, the assembled NiS@FeS/HS (+)||NiFeP/HS (−) anion exchange membrane electrolyzer requires 1.70 V@200 mA cm −2 and operates stably for over 1000 h. This work provides an effective bio‐magnetic strategy to construct metal sulfide pre‐catalysts with regulated spin states, which can inspire broad interest in the interdisciplinary integration of traditional corrosion engineering, physics, and emerging energy technologies.