CHARACTERIZATION OF NOBLE METAL ALLOY NANOPARTICLES PREPARED BY ULTRASOUND IRRADIATION

Solutions containing Au3+/Pd2+ and Au3+/Pt4+ ions were reduced in the presence of surfactants (SDS or PEG-MS) by ultrasound irradiation (200kHz, 4.2W/cm(2)). The obtained colloidal bimetallic nanoparticles of Au/Pd or Au/Pt were examined by UV-vis spectra, XRD, TEM, HRTEM, EDX, hydrogenation catalysis measurements and Au-197 Mossbauer spectroscopy. It was found that the prepared nanoparticles exhibited different morphologies with changing the irradiation parameters and the surfactants. The Au-197 Mossbauer spectroscopy clearly indicated that electronic structures of Au atoms of the core-shell structured nanoparticles are different from the bulk materials.