Magnetic field-assisted jet electrodeposition of Ni–Co based composite electrodes on nickel foam for alkaline water electrolysis

Developing efficient and stable oxygen evolution reaction (OER) catalysts is crucial to promoting the application of water electrolysis. Unlike conventional direct current or pulse electrodeposition, magnetic field-assisted jet electrodeposition (MFAJE) combined magnetic field assistance with electrolyte jetting to continuously renew the electrolyte, reduced the thickness of the diffusion layer on the substrate, and achieved uniform deposition on porous substrates. In this study, Ni–Co based composite electrodes were fabricated by jet electrodeposition, combined with nickel nanoparticles (Ni NPs) and magnetic field assistance to optimize their structure and electrochemical performance. The effects of Ni NPs and magnetic field on the surface morphology, crystal orientation, grain size and OER performance of the electrodes were investigated. The optimized Ni–Co/Ni NPs composite electrode exhibited a hierarchical flower-like micro-nano structure, enhanced (220) texture, and refined grains, resulting in a low overpotential of 290.36 mV at 10 mA cm −2 and a Tafel slope of 57.01 mV·dec −1 , when the magnetic field was 80 mT. Long-term chronopotentiometry tests confirmed its relatively stable performance over 50 h. Post-reaction morphology analysis revealed that the micro-nano structure was largely preserved, indicating that appropriately tuned MFAJE enhanced OER activity and structural stability. Therefore, MFAJE provided an energy field-assisted electrodeposition method that overcame the boundary layer and penetration limitations of direct current/pulse electrodeposition on porous metals, while also increasing the micro-nano structure of the electrode surface, providing a practical strategy for scalable non-noble metal OER electrodes. • Ni–Co/Ni NPs electrodes fabricated by magnetic field–assisted jet electrodeposition (MFAJE). • Hierarchical flower-like micro-nano structures markedly increase surface area. • Electrodes show excellent oxygen evolution reaction activity and long-term stability. • MFAJE extends to electrode fabrication on other porous substrates.