Construction of solid-iodine-regulated Cu₂O-Cu (200) heterointerface electrocatalyst for enhancing the CO₂RR to ethylene by promoting the asymmetric

Electrocatalytic reduction of carbon dioxide (CO₂RR) to multi-carbon (C₂₊) products offers a promising pathway toward carbon circularity. Achieving efficient and selective CO₂-to-C₂₊ conversion requires overcoming Cu⁺ instability and precisely tailoring exposed Cu facets governing C–C coupling activity/product selectivity, yet remains challenging. Here, a CuI surface-confined reduction coupled with electrochemical reconstruction strategy was proposed, the resulting CuI-R electrocatalyst possessed stable Cu₂O-Cu (200) heterointerfaces during the CO₂RR process. Benefited from the unique structure, it delivers an outstanding CO₂RR performance with ethylene Faradaic efficiency of 71 % and a C₂H₄ partial current density of −459.1 mA cm⁻², outperforming most of the documented electrocatalysts. Operando spectroscopy and DFT calculations revealed that compared to the Cu₂O-Cu (111), Cu₂O-Cu (200) interfaces strengthened *CO adsorption and promoted asymmetric *CO-*CHO coupling, and then effectively enhancing the C₂₊ products. This work establishes a simple and scalable interface-facet co-engineering strategy for constructing durable, high-performance Cu catalysts for selective CO₂-to-ethylene conversion.