How the Porous Transport Layer Interface Affects Catalyst Utilization and Performance in Polymer Electrolyte Water...

Area of Science:

• Electrochemistry
• Materials Science
• Chemical Engineering

Background:

• Cost reduction and scalability of electrolyzer technologies are critical for industrial decarbonization.
• Efficient utilization of scarce iridium catalysts is essential for polymer electrolyte water electrolysis.
• Interfacial properties between porous transport layers (PTLs) and catalyst layers (CLs) significantly influence catalyst performance.

Purpose of the Study:

• To investigate the relationship between PTL-CL interface properties and electrochemical performance.
• To understand how PTL geometry affects catalyst utilization at varying current densities.
• To identify mechanisms of catalyst deactivation under operational conditions.

Main Methods:

• Fabrication of a matrix of 2D interface layers between PTLs and CLs.
• Electrochemical performance characterization and overpotential analysis.
• Experimental estimation of water penetration depth and 3D-multiphysics modeling.

Main Results:

• Catalyst utilization decreases at higher current densities due to dry-out, oxygen saturation, or high CL resistance.
• Experimentally determined water penetration in the CL under the PTL was approximately 20 μm.
• Gas accumulation under PTL lands hinders water distribution, impacting performance and resistance.

Conclusions:

• PTL-CL interface engineering is crucial for optimizing catalyst utilization and electrolyzer efficiency.
• Understanding interfacial phenomena can guide the design of improved PTLs to reduce iridium loading.
• This research contributes to achieving cost reduction and performance targets in water electrolysis technologies.