抄録
Binary alloy nanoparticles of Au-Pd and Au-Pt were tried to prepare by a sonochemical method. Samples were made from mixtures of argon-saturated aqueous solutions of NaAuCl_4 ,PdCl_2, and H_2PtCl_6 from simultaneous reduction by ultrasonic irradiation. Analyses with UV-vis spectra indicated that Au^<3+> ions were first reduced and after their consumption reduction of Pd^<2+> ions or Pt^<4+> ions set in. The obtained colloidal dispersions were stable for more than several months in the presence of surfactant. Characterizations of the prepared nanoparticles with various metal content ratios were carried out by electron microscopic observations. Analyses by HRTEM of the products from Au^<3+> and Pd^<2+> ions directly indicated that they are Au-core / Pd-shell structured nanoparticles. In the case of Au-Pt products, UV-vis spectra of colloidal dispersions and XRD measurements suggested that Au-Pt nanoparticles also consist of Au core and Pt shell.
