Stabilized Triple-Phase Interface at CF₄ Plasma Bombarded Cu Gas Diffusion Electrode for CO₂-to-C₂H₄ Valorization

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Copper-based gas diffusion electrodes (GDEs) are promising for converting CO2 into valuable chemicals and fuels.
• Challenges include slow C2+ product formation kinetics and competing hydrogen evolution reactions.
• Effective electrolyte management is crucial for optimizing CO2 electroreduction.

Purpose of the Study:

• To develop a modified Cu/PTFE GDE for enhanced CO2-to-C2H4 conversion.
• To investigate the underlying mechanisms responsible for improved catalytic performance.
• To demonstrate the effectiveness of surface modification for CO2 valorization.

Main Methods:

• Fabrication of a roughened hydrophobic Cu/PTFE GDE using CF4 plasma bombardment.
• Electrochemical characterization and performance evaluation of the modified GDE.
• Online electrochemical mass spectrometry (OEMS) for reaction product analysis.
• Molecular dynamics (MD) simulations to probe interfacial phenomena and reaction mechanisms.

Main Results:

• The CF4 plasma-treated GDE significantly enhanced CO2 to ethylene (C2H4) electrosynthesis.
• OEMS data showed increased CO2 consumption and CO utilization, with reduced H2 generation.
• MD simulations revealed improved electrolyte management, maintaining a high local CO2/H2O ratio.
• Enhanced C-C coupling kinetics were attributed to Cu(δ+) sites adjacent to electron-withdrawing fluorocarbons.

Conclusions:

• Surface modification of Cu GDEs via CF4 plasma treatment is an effective strategy for CO2 valorization.
• The improved performance stems from enhanced CO2/H2O ratio management and optimized C-C coupling kinetics.
• This work provides insights into designing advanced catalysts for efficient CO2 electroreduction.