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

Cu-based gas diffusion electrodes (GDEs) hold the potential to produce carbon-neutral fuels and value-added chemicals from CO₂ greenhouse gas at substantial current densities, yet they are challenged by the sluggish reaction kinetics toward C₂₊ product production and the fierce competition of H₂ evolution from electrowetted/flooded catalyst layers. Herein, we develop a roughened hydrophobic Cu/PTFE GDE via CF₄ plasma bombardment and demonstrate its effectiveness in facilitating CO₂-to-C₂H₄ valorization. Online electrochemical mass spectrometry reveals that the enhanced C₂H₄ electrosynthesis is correlated with the increased rates of CO₂ consumption and CO utilization, as well as a reduction in H₂ generation upon CF modification. Molecular dynamics simulations highlight the significant promotional effect of electrolyte management sustaining a high local [CO₂]/[H₂O] ratio near the CF-Cu surface, where the improved C-C coupling kinetics is attributable to the abundant Cu^δ+ sites adjacent to surface-bonded fluorocarbons with electron-withdrawing character.