Enhancing Electrochemical CO₂ Reduction via Redox Non‐Innocent Spheres in Copper‐Coordinated Covalent Organic Frameworks

Abstract Significant efforts have been dedicated to the development of highly efficient electrocatalysts for electrochemical CO₂ reduction reactions (eCO₂RR). The outer coordination spheres of catalytic centers may play a pivotal role in the reaction pathway and kinetics for eCO₂RR. Herein, three single copper sites coordinated Aza‐fused conjugated organic frameworks (Aza‐COFs‐Cu) with different outer coordination spheres around Cu sites are designed. Experiment and density functional theory (DFT) calculation results reveal that the redox non‐innocent outer spheres around Cu sites significantly influence the catalytic performance of Aza‐COFs‐Cu for eCO₂RR. When adjacent redox non‐innocent groups of uncoordinated aromatic‐N and quinone around the Cu centers act as the symmetry‐breaking sites, the energy‐consuming activation process of CO₂ molecules can be accelerated via the H⁺/e⁻ transfer process to form *COOH intermediates, which will significantly improve the performance for eCO₂RR. This study provides a new perspective on the design of more advanced electrocatalysts for eCO₂RR through redox non‐innocent spheres engineering.