Unraveling Structure‐Dependent Performance of Cu–N–C Molecular Catalysts for Electrocatalytic CO ₂ Methanation

High‐rate CH 4 electrosynthesis offers a promising strategy for converting CO 2 into energy‐dense fuels compatible with existing natural gas infrastructure. Cu–N–C molecular catalysts with well‐defined Cu–N 4 sites show strong potential for CO 2 ‐to‐CH 4 production, yet the role of the macrocyclic backbone remains unclear. Herein, we compare two representative Cu–N–C molecular catalysts, copper phthalocyanine (CuPc) and copper tetraphenylporphyrin (CuPr), to clarify how the macrocyclic backbone influences CO 2 ‐to‐CH 4 electrocatalysis. When supported on conductive carbon and integrated into gas‐diffusion electrodes, CuPc markedly outperforms CuPr, achieving a CH 4 Faradaic efficiency of 79.5%, a high partial current density of −575 mA cm −2 , a mass activity of 19 166.7 A g −1 , and stable operation for over 80 h at −150 mA cm −2 . Characterization results suggest that the Pc‐macrocyclic backbone modulates the electronic structure of the Cu center and interfacial charge‐transfer behavior, possibly through its extended π‐conjugated Pc‐ring and bridge‐N environment. Theoretical calculations reveal a favorable CH 4 ‐forming pathway on the CuPc/C model, with a lower free‐energy barrier for the potential‐determining step than that reported for CuPr, suggesting facilitated CH 4 formation. These findings indicate that the macrocyclic backbone can regulate reaction pathways and intermediate adsorption energetics, providing mechanistic insight and design guidance for molecular catalysts for CO 2 ‐to‐CH 4 electroreduction.