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 CFx modification. Molecular dynamics simulations highlight the significant promotional effect of electrolyte management sustaining a high local [CO2]/[H2O] ratio near the CFx-Cu surface, where the improved C-C coupling kinetics is attributable to the abundant Cuδ+ sites adjacent to surface-bonded fluorocarbons with electron-withdrawing character.