Alternating Magnetic Field‐Enhanced Alkaline Hydrogen Evolution on Co‐Doped Mn 3 O 4

ABSTRACT As non‐precious metal catalysts for the hydrogen evolution reaction (HER), the performance of transition metal oxides is limited by electronic‐state tuning from static doping strategies. This work proposes a novel strategy for dynamically regulating the electronic state of catalysts using an alternating magnetic field (AMF). We synthesized a series of Mn x Co 3‐x O 4 catalysts, where Co substitution enriches high‐spin Mn 2+ centers and introduces lattice flexibility. Under a low‐energy AMF, the magnetic moments of high‐spin Mn 2+ undergo forced precession. Through dynamic magneto‐structural coupling within the compliant lattice, this spin dynamics acts as a continuous structural perturbation that provides a pathway for dynamic orbital regulation, potentially driven by the lifting of d‐orbital degeneracy. This optimized orbital configuration enables a favorable binding energy with H* intermediates, accelerating the sluggish Volmer step and enhancing HER activity. Under the AMF, the Mn 2.5 Co 0.5 O 4 exhibits a low overpotential of 13 mV at 10 mA cm −2 , outperforming previously reported manganese‐based oxides. This work offers a strategy to dynamically lift d‐orbital degeneracy for efficient water electrolysis.