Preparation and Oxygen Evolution Performance of NiS2-MnS/NF Catalysts

Efficient and corrosion-resistant electrocatalysts are essential for the oxygen evolution reaction (OER), particularly in chloride-containing electrolytes such as seawater. Herein, a self-supported NiS 2 –MnS heterostructured catalyst grown on nickel foam (NiS 2 –MnS/NF) was fabricated through a combined electrodeposition–sulfidation strategy. Structural characterizations reveal the formation of a nanosheet-based heterostructure with uniformly distributed elements and abundant exposed active sites. In 1 M KOH electrolyte, the NiS 2 –MnS/NF electrode requires overpotentials of 269 and 355 mV to achieve current densities of 20 and 100 mA cm −2 , respectively, together with a small Tafel slope of 36 mV dec −1 and stable operation for 100 h. In simulated seawater electrolyte containing 1 M KOH and 0.5 M NaCl, the catalyst still maintains excellent OER activity, delivering overpotentials of 236 and 320 mV at the same current densities. The improved catalytic performance is attributed to the electronic interaction between NiS 2 and MnS phases and the structural evolution of the catalyst during OER. Post-OER characterizations indicate that the sulfide precursor undergoes in situ reconstruction to form NiOOH and MnOOH active species, which contributes to the enhanced catalytic activity. This work provides a promising strategy for designing efficient and corrosion-resistant electrocatalysts for seawater electrolysis.