Stretchable asymmetric dual-atom Cu(I) electrocatalyst for enhanced CO₂ reduction to C₂₊ products

Constructing precise catalytic sites and local microenvironments to achieve electrochemical CO₂ conversion to valuable C₂₊ products remains a great challenge. Here, a porous crystalline covalent organic framework (COF) containing Br-bridged dual single-atom Cu(I) sites with an asymmetric coordination environment was rationally designed and confirmed by combining single-crystal X-ray diffraction and X-ray absorption fine structure analyses. The as-synthesized COF-based single-atom Cu catalyst exhibits exceptional performance in the electrochemical CO₂ reduction reaction to C₂₊ products, which surpasses that of most previously reported single-atom catalysts with defined coordination structures. Operando Raman spectroscopy, theoretical calculations, and control experiments were employed to verify the mechanism behind the effectiveness of the catalyst. These investigations suggest that the flexible, asymmetrically coordinated dual-atom Cu(I) sites can lower the energy barrier for generating ∗CO and ∗COCHO intermediates, thereby promoting the formation of C–C bonds necessary for C₂₊ products.