Stabilizing Cu ⁺ Sites at Cu ₂ O(111)–ZrO ₂ Heterointerfaces for Durable and Selective CO ₂ -to-C ₂ H ₄ Electroreduction

Although Cu 2 O(111) is thermodynamically favorable for CO 2 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 Cu 2 O–ZrO 2 heterointerfaces that stabilize Cu + and promote C–C coupling. Using a zirconium-based metal-organic framework as a confined-conversion template, uniformly dispersed Cu 2 O(111)–ZrO 2 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 Cu 2 O(111)-based oxide heterointerfaces as effective platforms for durable and selective CO 2 RR to multicarbon products.