Copper Atom Pairs Stabilize *OCCO Dipole Toward Highly Selective CO2 Electroreduction to C2H4

Deeply electrolytic reduction of carbon dioxide (CO2) to high-value ethylene (C2H4) is very attractive. However, the sluggish kinetics of C-C coupling seriously results in the low selectivity of CO2 electroreduction to C2H4. Herein, we report a copper-based polyhedron (Cu2) that features uniformly distributed and atomically precise bi-Cu units, which can stabilize *OCCO dipole to facilitate the C-C coupling for high selective C2H4 production. The C2H4 faradaic efficiency (FE) reaches 51 % with a current density of 469.4 mA cm(-2), much superior to the Cu single site catalyst (Cu SAC) (similar to 0 %). Moreover, the Cu-2 catalyst has a higher turnover frequency (TOF, similar to 520 h(-1)) compared to Cu nanoparticles (similar to 9.42 h(-1)) and Cu SAC (similar to 0.87 h(-1)). In situ characterizations and theoretical calculations revealed that the unique Cu2 structural configuration could optimize the dipole moments and stabilize the *OCCO adsorbate to promote the generation of C2H4.