Hierarchical Superaerophobic Nanoarray Electrode (FeOOH/CoFe LDH) as an Efficient Oxygen Evolution Reaction Catalyst for Alkaline Seawater Electrolysis

The lack of highly efficient and long-term stable catalysts for the oxygen evolution reaction (OER) severely hampers the advancement of alkaline seawater electrolysis. Herein, a hierarchical superaerophobic OER catalyst electrode, FeOOH/CoFe layered double hydroxide (FeOOH/CoFe LDH), has been prepared on nickel foam through a one-step hydrothermal reaction as an efficient OER catalyst for alkaline seawater electrolysis. The hierarchical nanostructure provides abundant active sites for the catalyst; the superaerophobic property ensures sufficient contact between the catalysts and the electrolyte, and the interaction between FeOOH and CoFe LDH further enhances the OER activity. The FeOOH/CoFe LDH catalytic electrode exhibits remarkable OER performance in simulated seawater solution (1.0 M KOH + 0.5 M NaCl). Specifically, at an industrial current density of 400 mA cm–2, the overpotentials are just 320 mV at 25 °C and 257 mV at 60 °C. Meanwhile, after 300 h of stability testing at a current density of 100 mA cm–2, the overpotential of the electrode increases by a mere 19 mV. This work will afford a simple approach for designing effective electrodes for alkaline seawater electrolysis.