Engineering Gradient Porosity and Wettability to Construct High-Efficiency Low-Iridium Anode for Proton Exchange...

Area of Science:

• Electrochemistry
• Materials Science
• Chemical Engineering

Background:

• Proton exchange membrane water electrolysis (PEMWE) is key for sustainable hydrogen production.
• High iridium (Ir) catalyst loading is often required due to transport limitations in conventional anodes.
• Optimizing anode architecture is crucial for improving PEMWE efficiency and reducing costs.

Purpose of the Study:

• To design and evaluate a novel dual-gradient (DG) anode architecture for PEMWE.
• To enhance catalyst utilization and mass transport within the anode.
• To reduce iridium loading while maintaining high performance and stability.

Main Methods:

• Fabrication of a DG anode with tailored porosity and wettability gradients.
• Electrochemical characterization including performance testing and stability studies.
• Pore-scale multiphysics simulations to visualize transport phenomena.

Main Results:

• The DG anode increased the electrochemically active surface area by 1.7 times.
• Mass transport and ohmic overpotentials were reduced by 65% and 7%, respectively.
• Achieved 1.91 V at 4 A cm⁻² with 0.2 mg cm⁻² Ir loading and stable operation for over 500 h at 1.5 A cm⁻².

Conclusions:

• The DG anode design effectively maximizes three-phase interfaces and enhances mass transport.
• This strategy enables high-performance, low-cost PEMWE by significantly reducing iridium requirements.
• The findings offer a promising pathway for efficient and economical green hydrogen production.