Atomically precise alkynyl-protected AgCu nanoclusters: synthesis, structure analysis, and electrocatalytic CO reduction application.

We report the synthesis, structure analysis, and electrocatalytic CO reduction application of AgCu(CCAr)(PPh)Cl (abbreviated as AgCu, CCAr: 3,5-bis(trifluoromethyl)phenylacetylene) nanoclusters. AgCu has characteristic absorbance features and is a superatomic cluster with 2 free valence electrons. Single-crystal X-ray diffraction (SC-XRD) revealed that the metal core of AgCu is composed of an AgCu icosahedron connected by two Ag tetrahedra at the two terminals of the Cu-Ag-Cu axis. Notably, AgCu exhibited excellent catalytic performance in the electrochemical CO reduction reaction (eCORR), manifested by a high CO faradaic efficiency of 95.26% and a large CO current density of 257.2 mA cm at -1.3 V. In addition. AgCu showed robust long-term stability, with no significant drop in current density and FE after 14 h of continuous operation. Density functional theory (DFT) calculations disclosed that the high selectivity of AgCu for CO in the eCORR process is due to the shedding of the -CCAr ligand from the Ag atom at the very center of the Ag unit, exposing the active site. This study enriches the potpourri of alkynyl-protected bimetallic nanoclusters and also highlights the great advantages of using atomically precise metal nanoclusters to probe the atomic-level structure-performance relationship in the catalytic field.