Fe-Doped Ni₃S₂ Nanosheets on Ni Foam for Alkaline Seawater Oxidation

Facile and controllable synthesis of efficient and stable nonprecious electrocatalysts for the oxygen evolution reaction (OER) is crucial for prospective sustainable energy conversion and storage technologies. Iron-doped nickel sulfide nanosheet electrodes were synthesized through simple in situ sulfidation of nickel foil with ferrous chloride, which resulted in the formation of ultrathin Fe-doped Ni 3 S 2 nanosheets on the Ni foam (NF) substrate (Fe x -Ni 3 S 2 /NF). The developed Fe 1 -Ni 2 S 3 /NF electrocatalyst shows superb catalytic activity during the oxygen evolution reaction, owing to its high intrinsic activity, abundant active sites, and a superior transfer coefficient, requiring low overpotentials of only 244 and 306 mV at 100 mA cm –2 for the OER in 1.0 M KOH and 1.0 M KOH + 0.5 M NaCl solutions. This catalyst can maintain stable electrolysis in alkaline seawater for more than 100 h. The excellent activity and stability of this catalyst proved it to be an economical alternative to commercial noble metal-based catalysts in renewable energy-related technologies.