Manipulating the C─C Coupling Pathway via Switchable Dual‐Ligand Mediation in Copper(I) Nanoclusters for Selective CO 2 Electroreduction to Ethylene/Ethanol

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Atomically precise nanoclusters (Cu NCs) offer an unmatched view of how active‐site chemistry steers CO 2 electroreduction, yet fine control over competing C 2 products remains elusive. Here we introduce a switchable dual‐ligand strategy that decorates an identical Cu 13 H 10 core with tailored thiolate (‐SR) and phosphine (‐PR 3 ) ligands, creating three isostructural catalysts (NC1 to NC3) whose surface electronics diverge by design. A single‐step change in electron‐withdrawing ligand flips selectivity from C 2 H 4 (Faradaic efficiency, FE C2H4 ≈ 33 %) to EtOH ( FE EtOH ≈ 31 %) without sacrificing ≥ −0.2 A·cm −2 current density. In situ ATR‐SEIRAS and DFT reveal that ‐SR ligands accelerate *COCHO → *CCO dehydration toward C 2 H 4 , whereas electron‐withdrawing ‐PR 3 ligands stabilize *COCH 2 O route to EtOH. These insights deliver a clear design rule: modulate Cu ẟ+ sites through ligand induction to program C─C coupling pathways on demand.