Synthesis, structure anatomy, and catalytic properties of Ag 14 Cu 2 nanoclusters co-protected by alkynyl and phosphine ligands.

We report the synthesis, structure anatomy, and catalytic properties of Ag 14 Cu 2 (CCAr F ) 14 (PPh 3 ) 4 (CCAr F : 3,5-bis(trifluoromethyl)phenylacetylene) nanoclusters, denoted as Ag 14 Cu 2 . Ag 14 Cu 2 has a robust electronic structure with two free valence electrons, and it has a distinctive absorbance feature. Single-crystal X-ray diffraction (SC-XRD) disclosed that Ag 14 Cu 2 possesses an octahedral Ag 6 metal kernel capped by two Ag 4 Cu 1 (CCAr F ) 7 (PPh 3 ) 2 metal-ligand units. Remarkably, it exhibits excellent bifunctional catalytic performance for 4-nitrophenol reduction and the electrochemical CO 2 reduction reaction (eCO 2 RR). In 4-nitrophenol reduction, it adopts first-order reaction kinetics with a rate constant of 0.137 min -1 , while in the eCO 2 RR, it shows a CO faradaic efficiency (FE CO ) of 83.71% and a high current density of 92.65 mA cm -2 at -1.6 V vs. RHE. Moreover, Ag 14 Cu 2 showed robust long-term stability with no significant decay in current density and FE CO over 10 h of continuous operation in the eCO 2 RR. This study not only enriches the potpourri of alkynyl-protected bimetallic AgCu nanoclusters, but also demonstrates the great potential of employing metal nanoclusters for bifunctional catalytic applications.