Investigation on Reactivity and Selectivity of Electrocatalytic CO 2 Reduction in Photochemically Synthesized Ag 19 and Alloyed Ag 19 Cu 2 and Ag 12 Cu 7 Nanoclusters

Atomically precise nanoclusters are desirable for understanding the structure–property relationships in the electrocatalytic CO 2 reduction reaction (eCO 2 RR), but suitable related models are lacking, especially those of low- or zerovalent noble metal nanoclusters and their alloyed analogues. We first developed a photochemical method toward silver nanocluster Ag 19 (4- t BuPhC≡C) 14 (Dpppe) 3 (SbF 6 ) 3 ( Ag 19 - 2e ) and then related copper-doped alloyed nanocluster Ag 12 Cu 7 (4- t BuPhC≡C) 14 (Dpppe) 3 Cl 3 (SbF 6 ) 2 ( Ag 12 Cu 7 - 0e ). Herein, we present a larger alloyed nanocluster, Ag 19 Cu 2 (4- t BuPhC≡C) 16 (Dpppe) 4 (SbF 6 ) 3 ( Ag 19 Cu 2 - 2e ) and investigate the relationship between the structures and the eCO 2 RR performance of those related nanoclusters. The UV–vis and mass spectra revealed that Ag 19 Cu 2 - 2e forms via light-induced Ag 19 - 2e generation followed by Cu­(II) attachment. eCO 2 RR tests showed that Ag 19 - 2e is the least efficient, while its dicopper alloyed Ag 19 Cu 2 -2e favors formate, highlighting the important role of copper doping in regulating Ag cluster catalysis. This conclusion is further confirmed by the good catalytic performance of Ag 12 Cu 7 - 0e , which demonstrated the best C 1 product selectivity for both CO and formate. Experimental and theoretical calculations indicate that its excellent catalytic performance is attributed to the removal of Cl ligands, exposing active Ag sites for launching the eCO 2 RR process. This work not only demonstrates that copper-doped silver nanoclusters significantly enhance catalytic activity but also reveals that varying copper doping levels enable modulation of product selectivity in eCO 2 RR.