title: Synthesis and catalytic activity of gold-silver binary nanoparticles stabilized by PAMAM dendrimer.
abstract: Gold-silver binary nanoparticles, which feed atomic ratios of gold to silver were 3:1, 1:1, and 1:3, were prepared. These particles were stabilized by amine-terminated (generation (G) 3.0 and 5.0) and carboxyl-terminated (G 3.5 and 5.5) poly(amidoamine) (PAMAM) dendrimers in water. UV-vis spectra indicate that the particles are not mere physical mixtures of monometallic particles or core/shell type but alloy. According to transmission electron microscope (TEM) observation, the mean diameters of the particles were 7-10 nm for silver particles and 3-4 nm for both gold and alloy particles, respectively. Catalytic activities for reduction of p-nitrophenol were investigated by monitoring the absorbance at 400 nm during the reaction. They were proportional to the feed ratio of gold in the particles and showed a maximum at the ratio of Au:Ag=3:1.
authors.affiliation: Department of Applied Chemistry, Faculty of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Endo
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Yoshimura
authors.forename: Kunio
authors.initials: K
authors.lastname: Esumi