Magnetic Field-Assisted Electrodeposition of Fe₃O₄ Nanoparticles on Ni as Bifunctional Electrocatalyst for Overall Water Splitting

Hydrogen energy is gaining widespread attention as a green energy source. However, the existing catalysts have high overpotential and kinetic reaction energy barriers, which have seriously affected the catalytic efficiency of hydrogen production from overall water splitting, and the existing metal catalysts cannot be used on a large scale because of scarce resources and high costs. Therefore, it is an urgent need to find an excellent stable transition, low-cost, and high-activity metal-based bifunctional catalyst. In this work, a method is proposed to prepare Ni/Fe 3 O 4 catalytic electrodes by modulating the magnetic field to guide the adsorption of magnetic nanoparticles Fe 3 O 4 on the catalytic electrode surface. It was found that in the case of the added 5 g/L Fe 3 O 4 magnetic nanoparticles coupled with a single magnetic field, the catalytic electrode was measured in an alkaline solution, and the overpotentials of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) reactions reached 143 and 262 mV at the current density of 10 mA cm –2, with Tafel slopes of 39 and 40 mV dec –1, respectively. Compared to existing transition metal catalytic electrodes, the Ni/Fe 3 O 4 catalytic electrode presents an outstanding catalytic performance in both HER and OER. Moreover, this work demonstrates that superior bifunctional catalytic electrodes with micro/nanostructures can be prepared by regulating different magnetic fields to guide the deposition of magnetic nanoparticles Fe 3 O 4, which provides theoretical evidence for the preparation of future bifunctional catalytic electrodes.