Bicarbonate‐Stabilized Cu ₂ O/Cu Heterointerfaces Enable Efficient Ethylene Electrosynthesis From Carbon Capture Solutions

The direct electrochemical conversion of carbon capture solutions into multi-carbon (C₂₊) products offers a sustainable alternative to decarbonize chemical manufacturing, bypassing energy-intensive CO₂ regeneration and purification steps in conventional CO₂ conversion technologies. However, it faces persistent challenges in selectivity and operational stability. Here, this study demonstrates that bicarbonate, an inherent component of carbon capture media, stabilizes Cu₂O/Cu heterointerfaces in laminate oxide-derived Cu (LOD-Cu) catalysts, enabling long-term ethylene (C₂H₄) production. In a zero-gap membrane electrode assembly (MEA) electrolyzer, bicarbonate electrolytes support a C₂H₄ Faradaic efficiency of ≈54% at 200 mA cm^-2 over 80 h of continuous operation. In situ spectroscopic analysis reveals that bicarbonate mitigates the full reduction of Cu₂O, preserving interfacial motifs that are critical for C─C coupling. This work uncovers bicarbonate's role in stabilizing Cu₂O/Cu heterointerfaces, thereby preserving catalytically active motifs and enabling efficient, durable C₂H₄ production. It provides a practical strategy for integrating carbon capture with renewable C₂H₄ chemical synthesis.