A Highly Active CoFe Layered Double Hydroxide for Water Splitting.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Advanced catalysts are essential for efficient energy conversion and storage.
• Oxygen evolution reaction (OER) catalysts require high activity, cost-effectiveness, and durability.
• Layered double hydroxides (LDHs) show promise as OER catalysts.

Purpose of the Study:

• To synthesize and characterize a highly active and stable CoFe layered double hydroxide (CoFe LDH) catalyst for OER.
• To investigate the effect of Co/Fe ratios on the catalytic performance.
• To evaluate the long-term durability of the optimized catalyst on a 3D electrode.

Main Methods:

• Facile synthesis of CoFe LDH with tunable Co/Fe ratios (0.5–7.4).
• Electrochemical characterization including onset potential and Tafel slope measurements.
• Fabrication of a 3D porous electrode by loading CoFe LDH onto Ni foam (NF).

Main Results:

• Catalyst performance strongly depended on the Co/Fe ratio.
• The Co2Fe1 LDH sample exhibited superior OER activity with an onset potential of 1.52 V (vs. RHE) and a Tafel slope of 83 mV dec⁻¹.
• The 3D Co2Fe1 LDH/NF electrode achieved a sustained current density of 100 mA cm⁻² at 1.65 V (vs. RHE) for long-term OER.

Conclusions:

• CoFe LDH is a highly active and stable OER catalyst.
• Tuning the Co/Fe ratio is critical for optimizing catalytic performance.
• The developed 3D CoFe LDH/NF electrode shows significant potential for energy conversion and storage applications.