Modulating and Stabilizing High‐Index Cu ₂ S Facet Through Graphdiyne Enables Efficiently Electrocatalytic CO ₂ Reduction to Ethanol

ABSTRACT While high‐index facets offer superior catalytic activity, stabilizing these specific facets to favor ethanol production remains a key challenge in CO ₂ electroreduction catalyst design. Herein, we developed a graphdiyne (GDY)‐engineered Al‐doped Cu ₂ S catalyst (Al‐Cu ₂ Sv/GDY) with a stabilized high‐index Cu ₂ S facet (204) for facilitating CO ₂ ‐to‐ethanol conversion. Combined computational and experimental results demonstrate that the σ‐π synergistic bonding interaction between GDY and Al‐Cu ₂ S _V can selectively stabilize the high‐index Cu ₂ S (204) facet over the (104) facet, which in turn offers considerable Sv and enhances the π‐back donation, thereby promoting the oxophilicity and activity for efficient ethanol production. In contrast, the catalyst Al‐Cu ₂ S _V without GDY modification stabilizes the (104) facet with much lower activity for ethanol production. Studies confirm that compared to Al‐Cu ₂ S _V , Al‐Cu ₂ S _V /GDY can not only enhance ^* CO _top adsorption while promoting C‐C coupling, but also prevent C─O bonds scission, facilitating the formation of CH ₃ CHO ^* intermediate, thereby suppressing ethylene‐forming pathways. Subsequently, the Al‐Cu ₂ S _V /GDY catalyst achieves a remarkable Faradaic efficiency of 58.4% for ethanol at a high industrial‐level current density of 332.9 mA cm ⁻² with outstanding stability, representing more than a twofold improvement in FE over the catalyst Al‐Cu ₂ S _V . Our work offers a new idea for the rational design of high‐performance electrocatalysts for ethanol production.