Characterization of core–shell type and alloy Ag/Au bimetallic clusters by using extended X-ray absorption fine structure spectroscopy

Bimetallic silver and gold nanoparticles, a core–shell type structure, have been prepared by NaBH4 reduction method. The optical absorption spectra are recorded and compared with various ratios of Ag/Au alloy nanoparticles. The absorption spectra of bimetallic nanoparticles suggested the formation of core–shell structure. On the other hand, the high resolution transmission electron microscopy image of the nanoparticles confirmed the core–shell type configuration directly. Moreover, we studied the surrounding environment of core–shell type and alloy nanoparticles around gold atoms by using extended X-ray absorption fine structure spectroscopy.