A facile way to tune the chemical composition of gas-phase synthesized nanoclusters

Abstract

Cluster beam deposition (CBD) represents a powerful and versatile gas-phase synthesis method to fabricate nanoclusters that are in demand for various fields. However, the ready control of the chemical composition is of great significance and is still a challenge. In this work, the influences of sputtering power and Ar fluxes on the composition, size and shape of Sm-Co nanoclusters fabricated by the CBD method using a single composite target have been systematically investigated. The chemical composition of nanoclusters has been characterized by high-angle annular dark-field (HAADF) images and EDS of high-resolution transmission electron microscopy. As the sputtering power increases or the Ar fluxes decrease, the Co concentration in nanoclusters gradually increases, the variation of composition in nanoclusters is consistent with the electrocatalytic measurement results. The mechanism by which the composition changes is proposed to be associated with the distinct scattering for Sm and Co by Ar atoms. The composition of nanoclusters can be quantitatively tuned over a wide range by Ar fluxes and sputtering power. We demonstrate an effective way to synthesize nanoclusters with various chemical compositions and manipulate their corresponding functional properties, which advances the design and synthesis of nanoclusters and may be important for both basic research and applications.