Stabilizing Cu⁺ Sites at Cu₂O(111)-ZrO₂ Heterointerfaces for Durable and Selective CO₂-to-C₂H₄ Electroreduction

Although Cu₂O(111) is thermodynamically favorable for CO₂ electroreduction, ethylene production is limited by insufficient Cu⁺ stabilization, leading to modest selectivity and durability. Herein, we report an interfacial engineering strategy to construct nanoscale-coupled Cu₂O-ZrO₂ heterointerfaces that stabilize Cu⁺ and promote C-C coupling. Using a zirconium-based metal-organic framework as a confined-conversion template, uniformly dispersed Cu₂O(111)-ZrO₂ interfaces are generated within a conductive porous carbon matrix (CuZr@C). CuZr@C delivers FE_C2H4 = 72.1% at j_C2H4 = 39.0 mA cm^-2 (-1.3 V vs RHE) in an H cell with >70% retention after 120 h and j_C2H4 = 101.6 mA cm^-2 in a flow cell. Operando X-ray absorption spectroscopy and Raman confirm Cu⁺ stabilization and high local CO coverage at the heterointerface. Density functional theory reveals a reduced free-energy barrier of 0.68 eV for the rate-determining *OCCO → *OCCHO step, establishing Cu₂O(111)-based oxide heterointerfaces as effective platforms for durable and selective CO₂RR to multicarbon products.