A way to synergistically enhance hydrogen production with internal and external strategy: Magnetized cactus-like CoFe2O4 electrocatalyst enhance multiphysics mechanism

Hydrogen production through water electrolysis is hindered by the high kinetic barriers of the oxygen evolution reaction (OER). Here, cactus-like CoFe 2 O 4 in the form of nanosheet-assembled nanowires (CoFe 2 O 4 -NSW@NF) was synthesized to address this challenge. CoFe 2 O 4 -NSW@NF exhibits an excellent OER overpotential of ∼459 mV at 50 mA cm −2 . Under an applied magnetic field of 350 mT, the overpotential further decreases by ∼14 mV. This enhancement is attributed to the nanowires, which modulate the charge density on the nanosheet surface and promote the transition of disordered electrons into a well-aligned higher spin state. In addition, due to the tip-enhancement effect of the nanowires, the interface between the electrode and electrolyte exhibits a localized temperature increase of ∼4℃ and an approximately two-fold amplification of the magnetic field. These changes further intensify the magnetothermal and magnetohydrodynamic (MHD) effects induced by the magnetic field. This work effectively reduces the OER overpotential through the synergistic interaction of morphology and magnetic field, advancing the design of magnetic-effect catalysts for efficient water splitting.