Surface Defects in Atom-Precise Copper Nanoclusters and Their Different Catalytic Efficiencies

Abstract

Significant strides have been made in crafting uniform nanostructures leveraging inherent nanomaterial defects. However, basic understanding of the influence of these intricate defects on their catalytic activities at the atomic level remains challenging. Herein, we report two similar surface-vacancy defects in two distinct nanoclusters, [Cu 20 S(PET) 18 (P(Ph-p Me) 3 ) 3 ] 0 (Cu 20 S) and [Cu 13 H 10 (PPh 3 ) 7 (SPhCl 2 ) 3 ] 0 (Cu 13 H 10 ), and their strikingly different catalytic efficiencies (PET = 2-phenylethanethiol).Both clusters possess face-centered cubic packing (fcc) metal core with a defect exposing Cu(111) plane: Cu 20 S has a tetrahedral skeleton, while Cu 13 H 10 adopts a cubic configuration. Both defects can be conceptualized as the loss of a -Cu[P(PhR 3 ) 3 ] (R = p Me or H) vertex. Intriguingly, only Cu 13 H 10 exhibits remarkable efficiency in phenylacetylene semihydrogenation. NMR and theoretical studies identified the defect in Cu 13 H 10 as the catalytic active site. Specifically, DFT calculations revealed a subtle atomic distinction that governs the catalytic activity, namely: in Cu 13 H 10 , migration of the central interstitial hydride to the surface defect site activates the catalytic reactions; in Cu 20 S, copper migration creates an inefficient defect. It is hoped that this work will promote further research in the area of atomic-level chemistry of surface defects in nanoclusters, thereby paving the way for rational design of functional nanomaterials in fields such as catalysis.