High-yield synthesis of multispiked gold nanoparticles: Characterization and catalytic reactions

Non-"seed-mediated" room temperature synthesis of gold multispiked nanoparticles has been successfully achieved by adding NaOH acting as an accelerator for the reduction of gold ions in ethylene glycol without adding any external reducing agent. The multispiked nanoparticles are obtained in high yield and good monodispersity with a mean diameter of 75 +/- 10 nm. The absorption spectra of multispiked nanoparticles can be tuned by adding PVP as a stabilizer. The dependence of various properties of the multispiked nanoparticles on their conditions of formation is studied. The monometallic nanoparticles of Au so obtained are characterized by UV-vis spectroscopy, X-ray diffraction and transmission electron microscopy. Catalytic activity of the Au nanoparticles prepared in presence of PVP as a stabilizer is tested for the catalyzed reduction of o-nitro aniline to benzenediamine with an excess amount of NaBH4. The observed reaction rate is found to be pseudo-first-order with respect to o-nitro aniline. (C) 2012 Elsevier B.V. All rights reserved.