Selective C ₂ Electroproduction via Back Bonding in Asymmetric Copper‐Copper Motifs

Abstract CO 2 reduction reaction (CO 2 RR) is considered a highly attractive approach to reduce carbon emissions and yet encounters challenges in further converting *C 1 intermediates to valuable two‐carbon (C 2 ) products. Although copper‐based catalysts exhibit satisfactory adsorption energy for *C 1 species, the symmetrical charge distribution at adjacent copper sites leads to a strong repulsive force between adsorbed *C 1 . Herein, asymmetric copper‐copper (Cu F ‐Cu N ) motifs with distinct adsorption behaviors have been constructed on the F‐Cu 3 N substrate using the in situ isostructural substitution method. Compared to the high hybridization of Cu N 3d and N 2p orbitals, implanted F not only reduces the hybridization strength but also endows the Cu F with delocalized unpaired electrons. Accordingly, Cu F , beyond forming an isolated 3d z 2 ‐2p z σ bond between Cu and the key *C 1 intermediate (*CHO), offers additional 3d xz ‐2p z π back bonding to the *CHO. With dipole interactions in the asymmetric Cu F ‐Cu N motifs, the electrostatic repulsion between adjacent *CHO is diminished, efficiently promoting the C‐C coupling in CO 2 RR. Therefore, the Cu F ‐Cu N motifs achieve an exceptional C 2 selectivity of 81.5% with a partial current density of −325.9 mA cm −2 and a C 2 /C 1 selectivity ratio of 10.47. This nuanced manipulation of atomic interactions illuminates a path to potentially groundbreaking alterations in material characteristics.