Atomically precise M 15 (M = Au/Ag/Cu) alloy nanoclusters: Structural analysis, optical and electrocatalytic CO 2 reduction properties

Herein, we report the overall structure of phosphine and mercaptan co-protected [Au₇Ag₈(SPh)₆((p-OMePh)₃P)₈]NO₃ (Au₇Ag₈) nanocluster. As a point of comparison, we synthesize a nanocluster with the same structure but a different metal composition, [Au₁₃Cu₂(TBBT)₆((p-ClPh)₃P)₈]SbF₆ (Au₁₃Cu₂), as previously reported. We conduct a comprehensive comparison of their optical and electrocatalytic CO₂ reduction properties. The results reveal that the photoluminescence quantum yield (PLQY) of the Ag-doped Au₇Ag₈ nanocluster is 1.62%, which is seven times higher than that of the Cu-doped Au₁₃Cu₂ nanocluster (PLQY = 0.23%). Furthermore, the Au₁₃Cu₂ nanocluster demonstrates significantly enhanced catalytic selectivity for CO, with its CO faradaic efficiency ranging from 79.7% to 90.4%, compared to the Au₇Ag₈ nanocluster (CO faradaic efficiency: 67.2% to 77.7%) within the potential range of -0.5V to -1.1V. Structural analyses attribute the superior CO selectivity of Au₁₃Cu₂ to the copper dopant.