Manipulating anion intercalation into layered double hydroxide for alkaline seawater oxidation at high current density†

In this work, we propose a convenient strategy to manipulate anion intercalation into layered double hydroxide. The obtained NiFe LDH-Cl⁻ electrode shows outstanding OER performance with both low overpotentials and high stability in alkaline seawater at high current density. Ultra-low overpotentials of 255 mV and 350 mV are required in 1 M KOH and alkaline seawater at a current density of 200 mA cm⁻². In addition, NiFe LDH-Cl⁻ can stably operate at 200 mA cm⁻² for 100 h. In situ Raman studies reveal that the active γ-NiOOH is generated on NiFe LDH-Cl⁻ at a low potential by surface reconstruction, and Cl⁻ intercalation helps optimize the peak area ratio of E_g and A_1g, which can be favorable for the alkaline seawater OER.