Carbon-templated conductive oxide supports for oxygen evolution catalysis

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Proton exchange membrane (PEM) electrolyzers are crucial for hydrogen production.
• Efficient and stable oxygen evolution reaction (OER) catalysts are needed to reduce energy losses.
• Iridium dioxide (IrO2) is a promising OER catalyst, but high noble metal loading is a challenge.

Purpose of the Study:

• To develop a novel, cost-effective method for preparing supported IrO2 catalysts for OER in PEM electrolyzers.
• To improve catalytic activity and stability while minimizing noble metal content.
• To investigate the role of nanostructuring and conductive interlayers in catalyst performance.

Main Methods:

• Utilized carbon soot as a nanostructure template.
• Employed atomic layer deposition (ALD) for sequential coating with niobium-doped titanium oxide (NTO) and IrO2.
• Fabricated nanostructured NTO/IrO2 electrodes.

Main Results:

• Achieved ultrathin, highly pure IrO2 catalyst layers via ALD.
• NTO layer provided oxidation-stable conductivity between current distributor and catalyst.
• Electrodes exhibited high catalytic activity and good stability under various load conditions.
• Demonstrated significantly lower overpotential (∼250 mV at 1 mA cm-2) compared to particulate catalysts at low IrO2 loading (153 μg cm-2).

Conclusions:

• The novel ALD-based route using nanostructured templates is effective for low-loading IrO2 catalysts.
• The NTO interlayer enhances electrode stability and conductivity.
• This approach offers a promising strategy for developing highly active and stable OER catalysts for PEM electrolyzers, reducing reliance on expensive noble metals.