High-Efficiency Anion-Exchange Membrane Water Electrolyzer Enabled by Ternary Layered Double Hydroxide Anode

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Developing efficient and affordable oxygen-evolving electrodes is crucial for advancing anion exchange membrane (AEM) water electrolysis.
• Conventional nickel foam electrodes often require significant overpotentials for the oxygen evolution reaction (OER).

Purpose of the Study:

• To transform conventional Ni foam electrodes into high-performance OER catalysts through a controlled surface corrosion process.
• To investigate the catalytic properties of the resulting ternary NiFeV layered double hydroxide (LDH) nanosheet array for OER.

Main Methods:

• Surface corrosion of Ni foam electrodes using Fe3+ and V3+ cations.
• Characterization of the electrode material using techniques to confirm ternary NiFeV LDH nanosheet array formation.
• Electrochemical testing of the NiFeV LDH electrode for OER performance in 1 M KOH.
• Density functional theory (DFT) calculations to understand the catalytic mechanism.
• Assembly and testing of an AEM water electrolyzer using the developed electrode.

Main Results:

• The corroded Ni foam transformed into a ternary NiFeV LDH nanosheet array.
• The NiFeV LDH electrode achieved a current density of 100 mA cm−2 at an overpotential of 272 mV, outperforming IrO2 by 180 mV.
• DFT calculations indicated that vanadium incorporation and the LDH structure enhance OER activity.
• The AEM water electrolyzer with NiFeV LDH and Pt/C achieved 2.1 A cm−2 at 1.8 Vcell, comparable to proton exchange membrane electrolyzers.

Conclusions:

• Surface corrosion is an effective strategy to create advanced OER electrocatalysts from inexpensive materials.
• The NiFeV LDH electrode demonstrates superior OER activity and stability for AEM water electrolysis.
• This approach offers a promising pathway towards low-cost, high-efficiency AEM water electrolysis for green hydrogen production.