Oxygen‐Bridged Dual Catalytic Sites Enable Asymmetric C─C Coupling for Efficient CO ₂ Electroreduction to Ethanol

Abstract

Abstract Understanding C─C coupling pathways is essential for achieving selective CO 2 conversion into multi‐carbon products. However, controlling intermediates dimerization remains highly challenging due to both the complexity of the catalytic systems and the limited mechanistic knowledge into the C─C coupling process. In this work, a model dual‐site catalyst with precisely configured Fe‐O‐Cu sites is designed by covalently grafting iron‐phthalocyanine (FePc) onto copper nanowires via oxygen bridges (FeN 4 ‐O‐Cu NW), which enables probing of atomic‐level mechanistic insights into the C─C coupling pathways during electrochemical CO 2 reduction reaction (CO 2 RR). Remarkably, the FeN 4 ‐O‐Cu NW exhibits a 23.6‐fold enhancement in the ethanol‐to‐ethylene Faradaic efficiency ratio as compared to O‐Cu NW, achieving > 80% C 2+ Faradaic efficiency at an industrially relevant current density of 1 A cm −2 . 13 CO 2 / 12 CO co‐feed experiments together with a collection of operando /in‐situ characterizations reveal that the enhanced ethanol selectivity over FeN 4 ‐O‐Cu NW arises from asymmetric C─C coupling between *CO and *CHO intermediates, where *CO is generated at the low‐spin single‐Fe‐atom site, while *CHO is produced at the oxygen‐bridged Cu site. Density functional theory (DFT) calculations further unveil that the oxygen‐bridged Fe‐O‐Cu site can not only stabilize the in situ generated low‐spin Fe(II) active site for enhancing CO 2 activation and lowering *CO desorption energy but also construct an oxygen‐bridged Cu active site to stabilize the *OCHO intermediate, significantly lowering the *OCHO‐to‐*CHO conversion energy barrier, orchestrating an efficient asymmetric *CO─*CHO coupling path and boosting the CO 2 ‐to‐ethanol conversion.