Flooding Control by Electrochemically Reduced Graphene Oxide Additives in Silver Catalyst Layers for CO₂ Electrolysis

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrolyte flooding in gas diffusion electrodes (GDEs) hinders CO2 and CO electrolyzer performance.
• Developing stable and efficient GDEs is crucial for electrochemical CO2 conversion.

Purpose of the Study:

• To mitigate electrolyte flooding in GDEs for CO2 electrolysis.
• To enhance the stability and high-current performance of CO2 electrolyzers.

Main Methods:

• In situ electroreduction of graphene oxide (GO) to reduced graphene oxide (r-GO) within a silver catalyst layer on a carbon GDE.
• Fabrication of r-GO/Ag-coated GDEs and assessment of their performance in CO2 electrolysis.

Main Results:

• The r-GO/Ag-coated GDE demonstrated hydrophobicity, mitigating electrolyte flooding.
• Achieved sustained 94% Faradaic efficiency for CO over 8 hours at 100 mA·cm-2.
• Unmodified Ag-coated GDE showed a drop from 95% to 66% efficiency under similar conditions.

Conclusions:

• In situ electrochemical reduction of GO to r-GO is a cost-effective method to create flooding-resistant GDEs.
• The r-GO incorporation enhances catalyst layer roughness and electrochemically active surface area.
• This approach offers a practical solution for improving CO2 electrolyzer durability and efficiency.