Pre-doping Carbonate Ions into Nickel Hydroxide Interlayers Enables Long-Term Alkaline Seawater Oxidation

Chlorine corrosion for the oxygen evolution reaction (OER) electrode remains a major challenge for seawater electrolysis. Here, we propose a simple strategy to obtain the long-lifespan and high active OER electrode via pre-doping carbonate ions only into the nickel hydroxide interlayers as the anticorrosive and catalyst layer grown on nickel foam (NF) (Ni(OH)₂-CO₃^2-/NF). The experimental test and theory calculation reveal that the pre-doped CO₃^2- in the Ni(OH)₂ interlayers suppresses the Cl^- transport via enhancing its migration energy to inhibit chlorine corrosion. Consequently, the Ni(OH)₂-CO₃^2-/NF electrode lifespan reaches 900 h in alkaline-simulated seawater at 400 mA cm^-2, which is more than 300 times longer than that of the Ni(OH)₂/NF electrode without CO₃^2-. Meanwhile, CO₃^2- only in the Ni(OH)₂ interlayers let the electrode display higher activity than that of adding CO₃^2- in the electrolyte, which only needs 360 mV overpotential at a current density of 100 mA·cm^-2 in alkaline-simulated seawater.