Soft-Landing Deposition of Superatomic Cu9+/Ag9+ Clusters for Catalytic Hydrogenation of Acetylene.

Efficient preparation, isolation, and soft-landing deposition of stable clusters with atomic precision are important for developing new catalysts. However, small metal clusters are often highly susceptible to oxidation and prone to structural deformation on supports, which poses substantial challenges to experimental catalysis and theoretical calculations. In this study, we prepared pure Agn+ and Cun+ clusters and screened out superatomic clusters Ag9+ and Cu9+ by gas-phase reactions of sufficient collisions. We then deposited the two clusters onto different substrates using soft landing techniques. Characterization by X-ray photoelectron spectroscopy verified successful deposition and revealed that these superatomic clusters preserve unoxidized states at exposure to air, highlighting their unique stability rooted in superatomic eight-electron shell closure. We tested the catalysis of Ag9+ and Cu9+ clusters for acetylene hydrogenation and related hydrogen-deuterium exchange reactions. The results revealed that the Cu9+ clusters on TiO2 exhibit superior catalytic activity, which is associated with the enhanced cluster-support interactions and favorable H2 activation behavior. This study validates the applicability of superatom clusters for designing new catalysts, with enhanced stability and tailorable active sites.