Reaction Mechanisms of Well‐Defined Metal–N4 Sites in Electrocatalytic CO2 Reduction

Abstract Electrocatalytic CO 2 reduction to CO emerges as a potential route of utilizing emitted CO 2 . Metal‐N‐C hybrid structures have shown unique activities, however, the active centers and reaction mechanisms remain unclear because of the ambiguity in true atomic structures for the prepared catalysts. Herein, combining density‐functional theory calculations and experimental studies, the reaction mechanisms for well‐defined metal–N 4 sites were explored using metal phthalocyanines as model catalysts. The theoretical calculations reveal that cobalt phthalocyanine exhibits the optimum activity for CO 2 reduction to CO because of the moderate *CO binding energy at the Co site, which accommodates the *COOH formation and the *CO desorption. It is further confirmed by experimental studies, where cobalt phthalocyanine delivers the best performance, with a maximal CO Faradaic efficiency reaching 99 %, and maintains stable performance for over 60 hours.