Magnetoelectrodeposited Co‐Ni Electrocatalyst on Fe‐Modified Ni‐Foam for Alkaline Oxygen Evolution Reaction

Abstract Applying external magnetic field facilitates the oxygen evolution reaction (OER), but such a strategy is impractical for large‐scale applications. We introduce a scalable alternative by applying magnetic fields only during catalyst electrodeposition. We further propose a design principle for magnetoelectrocatalyst wherein electrocatalysis of active sites is enhanced by magnetic field impressed in the vicinity of active sites using a less active element having high magnetic saturation. This principle is demonstrated using monometallic systems (FTO/Ni and FTO/Co) and then extended it to develop a multimetallic magnetoelectrodeposited (MED) catalyst (NF/Fe‐NiCo‐MED). A Fe‐modified Ni‐foam (NF/Fe) substrate was prepared via galvanic displacement, onto which Ni, Co, or NiCo were electrodeposited under a 0.6 T field. The resulting NF/Fe‐NiCo‐MED magneto catalysts exhibited enhanced remanence, saturation magnetization, and ECSA and lower charge‐transfer resistance compared to counterparts NF/Fe‐NiCo‐no MED deposited without external magnetic field. The NF/Fe‐NiCo‐MED demonstrated excellent OER performance, with a low overpotential of 273.26 mV at 100 mA/cm 2 and sustained stability for 72 h in alkaline media. Notably, NF/Fe‐NiCo‐MED outperforms benchmark NiCo‐based layered double hydroxide (LDH) catalysts and even multimetallic systems operated under an external magnetic field during alkaline OER.