Understanding Au∼98Ag∼46(SR)60 nanoclusters through investigation of their electronic and local structure by X-ray absorption fine structure

Abstract

Here we report the electronic and local atomic structure of thiol-stabilized Au_∼98Ag_∼46(SR)₆₀ nanoclusters investigated by synchrotron radiation-based X-ray absorption fine structure (XAFS). Au L₃-edge X-ray absorption near edge fine structure (XANES) was used to examine the d band character of Au, which is highly related to the electronic, magnetic and catalytic activities of Au. It was observed that the d band hole population of Au in Au_∼98Ag_∼46(SR)₆₀ was higher than that of bulk Au. The formation of the AuAg alloy was confirmed by extended X-ray absorption fine structure (EXAFS). The EXAFS results also suggested that Au atoms in Au_∼98Ag_∼46(SR)₆₀ nanoclusters preferred to occupy the metal core sites, while the Ag atoms were mainly on the surface.