Selective C2 Electroproduction via Back Bonding in Asymmetric Copper‐Copper Motifs

CO2 reduction reaction (CO2RR) is considered a highly attractive approach to reduce carbon emission and yet encounters challenges in further converting *C1 intermediates to valuable two‐carbon (C2) products. Although copper‐based catalysts exhibit satisfactory adsorption energy for *C1 species, the symmetrical charge distribution at adjacent copper sites leads to a strong repulsive force between adsorbed *C1. Herein, asymmetric copper‐copper (CuF‐CuN) motifs with distinct adsorption behaviors have been constructed on the F‐Cu3N substrate using the in situ isostructural substitution method. Compared to the high hybridization of CuN 3d and N 2p orbitals, implanted F not only reduces the hybridization strength but also endows the CuF with delocalized unpaired electrons. Accordingly, CuF, beyond forming an isolated 3dz2‐2pz σ bond between Cu and the key *C1 intermediate (*CHO), offers additional 3dxz‐2pz π back bonding to the *CHO. With dipole interactions in the asymmetric CuF‐CuN motifs, the electrostatic repulsion between adjacent *CHO is diminished, efficiently promoting the C‐C coupling in CO2RR. Therefore, the CuF‐CuN motifs achieve an exceptional C2 selectivity of 81.5% with a partial current density of −325.9 mA cm−2 and a C2/C1 selectivity ratio of 10.47. This nuanced manipulation of atomic interactions illuminates a path to potentially groundbreaking alterations in material characteristics.