Metal-π Sites Localized Hydrogen-*CO Coupling for Enhanced CO2 Electromethanation.

Electrochemical CO2-to-CH4 conversion on Cu-N-C single-atom catalysts is fundamentally limited by *H/*CO spatial mismatch from numerous metal-free CN matrix, where the long-range hydrogen transfer easily causes *H coupling or *CO dimerization, ultimately impeding *CHO formation. Herein, we design a two-dimensional metal-organic polymer catalyst featuring spatially adjacent Cu and 1H-benzotriazole to form Cu-π units, which achieves a Faradaic efficiency of 61% for CH4 at 800 mA·cm-2. Using Infrared free-electron laser (IRFEL) nanospectroscopy, we identify the key Cu-π coordination environment and low-frequency bonding modes, unavailable by conventional IR techniques. Complementary in-situ synchrotron radiation IR, electrochemical experiments and theoretical calculations reveal that π sites adsorb hydrated cations, enabling localized hydrogen supply to adjacent *CO on Cu sites and suppressing long-range hydrogen transfer-induced side reactions. This inorganic-organic synergy paves a new pathway to spatially match *H and *CO, advancing efficient CO2-to-hydrocarbons conversion.