Silica-supported Ag-Au bimetallic nanosystems by XPS

Bimetallic Ag-Au/SiO2 nanosystems were synthesized by sequential deposition of Au and Ag on silica substrates via RF-sputtering. Sample preparation was accomplished at 60°C from Ar plasmas, using a constant sputtering time for gold (10 min), followed by different silver deposition times (5-20 min) in order to vary the Ag/Au ratio as well as the total metal content. A proper choice of the synthesis conditions allowed to obtain a controlled dispersion of silica-supported bimetallic nanoparticles with tailored size and shape, as evidenced by X-ray Photoelectron Spectroscopy (XPS), X-ray Excited Auger Electron Spectroscopy (XE-AES), Transmission Electron Microscopy (TEM), Selected Area Electron Diffraction (SAED), and optical absorption spectroscopy. This work is devoted to the XPS and XE-AES characterization of a representative Ag-Au/SiO2 specimen with an average nanoparticles size of 9?5 nm. In particular, detailed scans for the C1s, O1s, Si2s, Au4f, Ag3d and AgMNN regions and related data are presented and discussed.