Tailoring the Coordination Environment of Single‐Atom Catalysts for Enhanced Electrochemical CO ₂ ‐to‐CO Conversion Efficiency

ABSTRACT Exploring the influence of the coordination environment of single‐atom catalysts (SACs) on the electrochemical CO ₂ reduction reaction is vital for assessing the reaction mechanism and structure‐performance relationship. However, it is challenging to engineer the coordination configuration of isolated active metal atoms precisely. Herein, we strategically manipulate the coordination number of the Co–N _x configuration by simply changing the order of adding the metal precursor toward improved CO ₂ electrolysis performance. Compared with the symmetric Co–N ₄ coordination, the asymmetric Co–N ₃ coordination leads to reinforced Co–N interaction and downshifted 3d orbital energy toward the Fermi level of the active Co sites, promoting the activation of CO ₂ molecules and the formation of critical intermediate *COOH. The as‐designed Co–N ₃ SAC displays excellent Faradaic efficiency (FE) of 98.4% for CO ₂ ‐to‐CO conversion at a low potential of −0.80 V, together with decent FE over a wide potential range (−0.50 V to −1.10 V) and high durability. This study presents an ideal platform to manipulate the coordination number of atomically dispersed metal catalysts and provides a fundamental understanding of coordination configuration‐performance correlation for CO ₂ electroreduction.