Gold nanoparticles prepared by sonochemical method in thiol-functionalized ionic liquid

A convenient sonochemical method in preparation of gold nanoparticles capped by thiol-functionalized ionic liquid (TFIL) using hydrogen peroxide as a reducing agent was described in this paper. The obtained gold nanoparticles (GNPs) were characterized by ultraviolet-visible (UV-vis) absorption spectra, transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR) spectra. It is found that the molar ratio of gold atom in chloroauric acid to thiol group in TFIL (Au/S) has great effects on the particles size and distribution of GNPs. The FT-IR spectra reveal that the function of thiol-containing ionic liquids is to form the bond of S-Au for stabilization of the gold cluster. Small gold nanoparticles size of 2.7 +/- 0.3 nm with narrow uniform distributions can be obtained at the molar ratio of Au/S = 1:2 under ultrasound irradiation for 12 h. The reported method, which is performed in ionic liquid and hydrogen peroxide solution under ultrasound irradiation, is friendly to environment. (C) 2007 Elsevier B.V. All rights reserved.