Scalable NiFe layered double hydroxides for efficient electrocatalytic seawater oxidation at high current density

Area of Science:

• Electrochemistry
• Materials Science
• Green Chemistry

Background:

• Seawater electrolysis offers a sustainable pathway for green hydrogen production.
• Chloride-induced corrosion remains a significant barrier to practical seawater electrolysis.
• Developing robust electrocatalysts is crucial for overcoming these limitations.

Purpose of the Study:

• To develop a scalable and efficient electrocatalyst for alkaline seawater oxidation (ASO).
• To address and mitigate chloride-induced corrosion in seawater electrolysis.
• To enhance the durability and performance of electrocatalysts in harsh seawater environments.

Main Methods:

• Synthesis of sulfate-intercalated NiFe layered double hydroxide on nickel foam (S-NiFe LDH/NF).
• Electrochemical testing including chronoamperometry and cyclic voltammetry.
• Durability assessment using Membrane Electrode Assembly (MEA) testing.
• In situ characterization using Raman spectroscopy.

Main Results:

• S-NiFe LDH/NF achieved 1 A cm^-2 with a low overpotential of 375 mV.
• Exceptional stability demonstrated, operating for 1800 hours at 1 A cm^-2 and 200 hours at 500 mA cm^-2.
• Sulfate intercalation was shown to promote active γ-NiOOH formation and repel chloride ions.

Conclusions:

• S-NiFe LDH/NF is a highly effective electrocatalyst for ASO, overcoming chloride corrosion.
• The catalyst design offers a scalable and durable solution for green hydrogen production from seawater.
• Sulfate plays a key role in enhancing catalytic activity and material stability.