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

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/cm² 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.