Structure-Activity Relationships of the Structural Analogs Au 8 Cu 1 and Au 8 Ag 1 in the Electrocatalytic CO 2 Reduction Reaction.

Owing to the significant attention directed toward alloy metal nanoclusters, it is crucial to explore the relationship between their structures and their performance during the electrocatalytic CO 2 reduction reaction (eCO 2 RR) and discover potential synergistic effects for the design of novel functional nanoclusters. However, a lack of suitable analogs makes this investigation challenging. In this study, we synthesized a well-defined pair of structural analogs, [Au 8 Cu 1 (SAdm) 4 (Dppm) 3 Cl] 2+ and [Au 8 Ag 1 (SAdm) 4 (Dppm) 3 Cl] 2+ (Au 8 Cu 1 and Au 8 Ag 1 , respectively), and characterized them. Single-crystal X-ray diffraction analysis revealed that Au 8 M 1 (M=Cu/Ag) consists of a tetrahedral Au 3 M 1 core capped by three (Dppm)Au staples, one Au 2 (SR) 3 staple, one lone SR ligand, and a terminal Cl ligand. Ag and Cu were doped at the same site in the Au 8 M 1 nanoclusters, which has rarely been reported. Au 8 Cu 1 exhibited a significantly higher CO Faradaic efficiency (FE CO ; ~82.2 %) during eCO 2 RR than that of Au 8 Ag 1 (FE CO ; ~33.1 %). Density functional theory calculations demonstrated that *COOH is the key intermediate in the reduction of CO 2 to CO. The formation of *COOH on Au 8 Cu 1 is more thermodynamically stable than on Au 8 Ag 1 , and Au 8 Cu 1 shows a smaller *CO formation energy than that on Au 8 Ag 1 , which promotes the reduction of CO 2 . We believe that the structural analogs Au 8 Cu 1 and Au 8 Ag 1 offer a suitable template for the in-depth investigation of structure-property correlations at the atomic level.