Tuning Catalyst Activation and Utilization Via Controlled Electrode Patterning for Low-Loading and High-Efficiency...

Area of Science:

• Electrochemistry
• Materials Science
• Chemical Engineering

Background:

• Proton exchange membrane electrolyzer cells (PEMECs) are crucial for green hydrogen production.
• High iridium (Ir) catalyst loading in conventional electrodes is a significant cost factor.
• Understanding reaction interfaces is key to improving PEMEC efficiency.

Purpose of the Study:

• To propose a novel anode electrode concept using thin catalyst-coated liquid/gas diffusion layers (CCLGDLs).
• To investigate the impact of CCLGDL design and patterning on catalyst utilization and reaction kinetics.
• To visualize and understand reaction interfaces in situ within PEMECs.

Main Methods:

• Integration of Ir catalysts with thin, tunable Ti liquid/gas diffusion layers (LGDLs) via electroplating.
• Fabrication of CCLGDLs with regulated patterns.
• Development of a two-sided transparent, reaction-visible cell for in situ visualization.
• Analysis of cell performance and impedance spectroscopy.

Main Results:

• The proposed CCLGDL design achieves comparable performance to commercial electrodes using only 0.08 mg_Ir cm^-2, a 97% reduction in Ir usage.
• Catalyst utilization was augmented by approximately 24 times.
• In situ visualization revealed oxygen gas accumulation at the reaction interface, hindering active area and increasing impedance.
• Tuning CCLGDL patterns demonstrated the ability to modify mass transport, improving catalyst activation and utilization.

Conclusions:

• The CCLGDL concept offers a simplified fabrication process and significantly enhanced catalyst utilization for PEMECs.
• This approach provides a powerful tool for in situ research of reaction interfaces in PEMECs and similar devices.
• The findings pave the way for future electrode designs with reduced cost and improved efficiency.