Vertically Aligned FeOOH/NiFe Layered Double Hydroxides Electrode for Highly Efficient Oxygen Evolution Reaction.

Area of Science:

• Materials Science
• Electrochemistry
• Renewable Energy

Background:

• The oxygen evolution reaction (OER) is critical for renewable energy storage but often relies on expensive iridium-based catalysts.
• Developing cost-effective and highly efficient electrocatalysts is essential for advancing water electrolysis technologies.

Purpose of the Study:

• To synthesize and characterize a novel, low-cost electrocatalyst for the oxygen evolution reaction (OER).
• To evaluate the performance and stability of the developed catalyst in alkaline media and alkaline polymer electrolyte water electrolyzers (APEWE).

Main Methods:

• Fabrication of vertically aligned FeOOH/NiFe layered double hydroxides (LDHs) nanosheets on nickel foam (VA FeOOH/NiFe LDHs-NF).
• Electrochemical testing in a half-cell electrolyzer to determine overpotentials and current densities for OER.
• Performance evaluation in an alkaline polymer electrolyte water electrolyzer (APEWE) to assess voltage and energy efficiency.

Main Results:

• The VA FeOOH/NiFe LDHs-NF electrode exhibited high current densities at low overpotentials (10 mA cm⁻² at 208 mV, 500 mA cm⁻² at 288 mV).
• The electrode demonstrated good stability during OER in alkaline electrolyte.
• The APEWE using this electrode achieved 1.71 V at 200 mA cm⁻² and 2.041 V at 500 mA cm⁻², with energy efficiencies of 86.0% and 72.0%, respectively.

Conclusions:

• The binder-free, vertically aligned architecture of FeOOH/NiFe LDHs-NF facilitates strain relaxation and enhances catalytic activity and stability.
• This novel electrocatalyst presents a promising, cost-effective alternative to iridium-based catalysts for efficient water splitting in renewable energy applications.