Developing Catalysts Integrated in Gas-Diffusion Electrodes for CO₂ Electrolyzers

Area of Science:

• Electrochemistry
• Materials Science
• Chemical Engineering

Background:

• Growing demand for a carbon-neutral society drives active research in CO2 electrolysis.
• Electrochemical CO2 conversion requires catalysts with high Faradaic and energy efficiency for commercial viability.
• Various electrolyzer types (H-cell, flow cell, membrane-electrode assembly (MEA) cell) are used, each with transport limitations.

Purpose of the Study:

• To review recent advancements in integrating electrocatalysts into gas-diffusion electrodes (GDEs) for high-rate CO2 electrolysis.
• To discuss factors influencing GDE-based CO2 electrolyzer performance, including GDE and cell design.
• To highlight strategies for enhancing catalyst performance and stability in GDE systems.

Main Methods:

• Integration of electrocatalysts into GDEs for CO2 electrolysis.
• Utilizing flow or MEA cells to overcome mass transfer limitations of CO2 solubility.
• Employing strategies like microenvironment control (polymers, ligands) and novel cell designs (plasmonic catalysts, microbial biocatalysts).

Main Results:

• GDEs enable gaseous CO2 to reach catalyst layers, yielding high current densities and production rates.
• High partial current densities for gaseous (CO, CH4, C2H4) and liquid (formate, ethanol) products have been reported.
• Strategies such as polymer incorporation and ligand functionalization improve local intermediate concentrations and performance.

Conclusions:

• GDEs are essential for efficient CO2 electrolysis, enabling high production rates of value-added products.
• Catalyst performance in GDEs depends on intrinsic activity, electron conductivity, mass transfer, and stability.
• Advanced GDE designs and catalyst modifications are key to achieving commercially viable CO2 electrolysis.