Oxalate anions-intercalated NiFe layered double hydroxide as a highly active and stable electrocatalyst for alkaline seawater oxidation

Seawater electrolysis is gaining recognition as a promising method for hydrogen production. However, severe anode corrosion caused by the high concentration of chloride ions (Cl^⁻) poses a challenge for the long-term oxygen evolution reaction. Herein, an anti-corrosion strategy of oxalate anions intercalation in NiFe layered double hydroxide on nickel foam (NiFe-C₂O₄^²⁻ LDH/NF)is proposed. The intercalation of these highly negatively charged C₂O₄^²⁻ serves to establish electrostatic repulsion and impede Cl^⁻ adsorption. In alkaline seawater, NiFe- C₂O₄^²⁻ LDH/NF requires an overpotential of 337 mV to gain the large current density of 1000mA cm^⁻² and operates continuously for 500 h. The intercalation of C₂O₄^²⁻ is demonstrated to significantly boost the activity and stability of NiFe LDH-based materials during alkaline seawater oxidation. Copyright © 2024 Elsevier Inc. All rights reserved.