Multicomponent and Hierarchical Ni(OH)₂/NiFe₂O₄/Ni₃S₂ Nanosheets on Nickel Foam for Seawater Electrolysis

Developing highly efficient, durable, and easily available noble‐metal electrocatalysts is crucial for large‐scale seawater electrolysis but remains a challenge. Here, we report a high‐performance oxygen evolution reaction (OER) catalyst, Ni(OH) 2 /NiFe 2 O 4 /Ni 3 S 2 @NF, synthesized through a simple one‐step hydrothermal method, showcasing a low overpotential of 413 mV at a large current density of 1000 mA cm −2 , coupled with excellent stability at an industrial current density of 500 mA cm −2 for over 100 h in alkaline natural seawater solution. Such excellent OER performance is attributed to the abundant component and hierarchical architecture of Ni(OH) 2 /NiFe 2 O 4 /Ni 3 S 2 @NF catalyst, featuring 3D porous structure of interconnected nanosheets array, which endows more active sites and promotes efficient mass transport, further significantly enhancing catalytic activity and reaction kinetics. The anion exchange membrane water electrolyzer (AEMWE), featuring a Ni(OH) 2 /NiFe 2 O 4 /Ni 3 S 2 @NF anode and a MoNi@NF cathode, exhibits exceptional activity and stability in alkaline seawater, achieving an industrial current density of 1000 mA cm −2 at a low cell voltage of 2.35 V. This work offers valuable insights for the development of cost‐effective and robust OER electrocatalysts suitable for stable operation in harsh seawater electrolysis systems.