In situ synthesis of rosette-like Co-doped FeNiOOH/NF for seawater oxidation

The development of high activity and strong resistance to seawater corrosion oxygen evolution reaction (OER) electrocatalysts for seawater electrolysis has broad application prospects. Herein, we prepare Co-doped FeNiOOH rosette-like nanoflowers on nickel foam (NF) with different Co dosages by one-step solvothermal method. The Co_0.2-FeNiOOH/NF exhibits a low overpotential (η₁₀) of 185 mV and Tafel slope of 30 mV dec^-1 in 1 M KOH. Moreover, it shows a low η₁₀ of 244 mV in alkaline seawater electrolyte. The remarkable OER performance of Co_0.2-FeNiOOH/NF is ascribed to the fact that the introduction of Co regulates the morphology and electron structure of the material, which provides abundant active sites for the reaction and promotes charge transfer. In situ Raman results demonstrate that NiOOH and γ-FeOOH are the key active species for the OER. This study provides a feasible basis for seawater electrolysis over transition metal (oxy)hydroxides.