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

Abstract The direct electrochemical conversion of carbon capture solutions into multi‐carbon (C 2+ ) products offers a sustainable alternative to decarbonize chemical manufacturing, bypassing energy‐intensive CO 2 regeneration and purification steps in conventional CO 2 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 Cu 2 O/Cu heterointerfaces in laminate oxide‐derived Cu (LOD‐Cu) catalysts, enabling long‐term ethylene (C 2 H 4 ) production. In a zero‐gap membrane electrode assembly (MEA) electrolyzer, bicarbonate electrolytes support a C 2 H 4 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 Cu 2 O, preserving interfacial motifs that are critical for C─C coupling. This work uncovers bicarbonate's role in stabilizing Cu 2 O/Cu heterointerfaces, thereby preserving catalytically active motifs and enabling efficient, durable C 2 H 4 production. It provides a practical strategy for integrating carbon capture with renewable C 2 H 4 chemical synthesis.