Composite Proton Exchange Membranes with Interlayer Structure Containing Functional Catalyst Particles for Water...

Area of Science:

• Electrochemistry
• Materials Science
• Chemical Engineering

Background:

• Proton exchange membrane (PEM) water electrolysis is crucial for green hydrogen production.
• Thinner membranes are needed for cost-effectiveness but suffer from degradation and gas crossover.
• Radical scavengers and gas recombination catalysts can mitigate these issues.

Purpose of the Study:

• To investigate the positioning effects of radical scavenger and gas recombination catalyst interlayers in composite membranes.
• To optimize the composition and placement of these interlayers for enhanced PEM water electrolysis performance.
• To reduce ionomer degradation and hydrogen crossover in PEM water electrolyzers.

Main Methods:

• Fabrication and testing of composite membranes with cerium-zirconium oxide (Ce$_{0.5}$Zr$_{0.5}$O$_{2}$) radical scavenger interlayers.
• Optimization of cerium content in cerium-zirconium oxide for radical scavenging.
• Integration and evaluation of platinum (Pt) gas recombination interlayers and bi-functional Pt/Ce$_{0.25}$Zr$_{0.75}$O$_{2}$ interlayers.
• Analysis of ionomer degradation rates and hydrogen crossover percentages.

Main Results:

• Placing the Ce$_{0.5}$Zr$_{0.5}$O$_{2}$ interlayer near the cathode significantly reduced ionomer degradation.
• Ce$_{0.25}$Zr$_{0.75}$O$_{2}$ exhibited the highest radical scavenging activity.
• The Pt interlayer was most effective near the anode but caused additional degradation.
• A bi-functional Pt/Ce$_{0.25}$Zr$_{0.75}$O$_{2}$ interlayer mitigated Pt-induced degradation.
• The optimized composite membrane (Ce$_{0.25}$Zr$_{0.75O$_{2}$ near cathode, Pt/Ce$_{0.25}$Zr$_{0.75}$O$_{2}$ near anode) showed lowest degradation and crossover.

Conclusions:

• Strategic placement of interlayers is critical for PEM water electrolysis performance.
• The optimized composite membrane design extends projected lifetime by 7.4 times and reduces H$_{2}$ crossover by 4.4 times.
• This approach offers a promising pathway for developing more durable and efficient PEM water electrolyzers.