Cobalt-Doped Goethite-Type Iron Oxyhydroxide (α-FeOOH) for Highly Efficient Oxygen Evolution Catalysis

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• The oxygen evolution reaction (OER) is critical for energy conversion technologies.
• Developing low-cost, high-performance OER catalysts remains an urgent challenge.
• Iron oxyhydroxide (FeOOH) based materials are promising but require performance enhancement.

Purpose of the Study:

• To synthesize and evaluate cobalt-doped iron oxyhydroxide (Co-FeOOH) as an electrocatalyst for OER.
• To investigate the effect of controlled cobalt doping on the catalytic activity and durability.
• To establish a cost-effective strategy for high-performance OER catalysts.

Main Methods:

• Wet synthesis process to prepare nanoparticulate Co-FeOOH with controlled Co/Fe ratios (x ≤ 0.20).
• Fabrication of Co-FeOOH-coated glassy carbon electrodes.
• Electrochemical characterization in alkaline electrolyte, including overpotential, Tafel slope, and durability tests.

Main Results:

• Co$_{0.20}$Fe$_{0.80}$OOH achieved a current density of 10 mA cm$^{-2}$ at a low overpotential of 383 mV.
• Co doping significantly reduced the overpotential compared to pure α-FeOOH (580 mV).
• Co-doped catalyst exhibited a small Tafel slope (40 mV dec$^{-1}$) and excellent durability, attributed to increased active surface area and reduced charge-transfer resistance.

Conclusions:

• Cobalt doping is an effective strategy to enhance the OER performance of iron oxyhydroxide.
• The developed Co-FeOOH catalyst offers high efficiency and durability at a low cobalt content.
• This approach presents a promising pathway for designing cost-effective and high-performance OER catalysts.