Scanning Gas Diffusion Electrode Setup for Real-Time Analysis of Catalyst Layers.

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Evaluating electrodes for electrochemical energy conversion often involves trade-offs between simplified model systems and complex full-cell studies.
• Existing methods struggle to provide both rapid screening and fundamental insights into real catalyst layers under operational conditions.

Purpose of the Study:

• To introduce and validate a novel scanning gas diffusion electrode (S-GDE) half-cell for enhanced electrode evaluation.
• To bridge the gap between aqueous model systems and full-cell studies by integrating mass spectrometry.
• To enable simultaneous electrochemical measurements and direct detection of dissolved species and gaseous products.

Main Methods:

• Utilizing a scanning gas diffusion electrode (S-GDE) half-cell setup.
• Coupling the S-GDE with online gas mass spectrometry (GMS) and inductively coupled plasma mass spectrometry (ICP-MS).
• Investigating standard fuel cell electrodes (Pt/C) under elevated oxygen reduction reaction (ORR) current densities (up to 0.75 A cm⁻²).

Main Results:

• Successfully detected dissolved platinum ions and gaseous CO₂ to monitor platinum dissolution and carbon corrosion.
• Quantified electrochemically active surface area, ORR activity, and Pt dissolution rates, benchmarking against conventional methods.
• Observed suppression of Pt dissolution when oxygen (O₂) is purged into the catalyst layer.

Conclusions:

• The S-GDE half-cell is a feasible tool for rapid screening and fundamental studies of electrodes in electrochemical energy conversion.
• The integrated mass spectrometry approach provides crucial data on material stability and reaction byproducts under realistic conditions.
• The S-GDE technology is adaptable for various applications including fuel cells, water electrolysis, CO₂ conversion, and metal-air batteries.