Hierarchical Copper Catalyst with Ligand‐Bridged Nanoclusters for Stable and Large‐Current‐Density CO 2 ‐to‐C 2 Electrosynthesis

ABSTRACT Ligand‐modified electrocatalysts enable control of surface structure and active site environments, elevated selectivity in electrochemical CO 2 reduction. However, challenges arise that ligand coverage often blocks catalytic sites and reduces metallic conductivity, hindering the application of this strategy at high current densities. Here, by engineering a high‐density array of fluorinated aryl thiol ligand (SPhF 2 )‐protected copper nanoclusters on two‐dimensional copper nanosheets, we demonstrate the development of stable, efficient, and selective Cu electrocatalysts for CO 2 reduction into C 2 products. This design constructs a high concentration of accessible active sites while preserving conductivity through the underlying nanosheet, achieving a C 2 Faradaic efficiency of 95.6 % with a partial current density of −673.1 mA cm −2 . By integrating in situ spectroscopy with multiscale simulations, we reveal that the thiophenol anchors build a hydrophobic microenvironment while electronically tuning the copper active sites. This dual‐functionality stabilizes the crucial * CO intermediate coverage and significantly lowers the kinetic barrier for * CO dimerization, thus favoring the C−C coupling pathway. This strategy of designing ligand‐bridged cluster/support interfaces paves the way for overcoming the selectivity‐activity trade‐off in complex electrocatalytic reactions.