Silver nanoparticles: Ultrasonic wave assisted synthesis, optical characterization and surface area studies

Silver nanoparticles have been successfully synthesized by the sonochemical route using sodium borohydride and sodium citrate as the reducing agents. The effect of the reducing agents on the particle size and morphology has been studied by carrying out the two reactions at the same ultrasound frequency (20 KHz). The strong reducing agent (NaBH4) produced spherical silver nanoparticles of sizes 10 nm whereas sodium citrate led to much smaller silver nanoparticles of similar to 3 nm diameter. Powder X-ray diffraction studies reveal a high degree of crystallinity and monophasic silver particles. UV-Visible studies show the presence of a surface plasmon band at 405 nm. However the reflectance spectra give a broad band between 340 and 360 nm which is characteristic for the quasi-spherical silver nanoparticles. The specific surface area was found to be 2.6 and 13.1 m(2)/g and the pore radius was found to be 15.2 and 12.3 angstrom for silver nanoparticles obtained by the sodium borohydride and sodium citrate reduction respectively. (C) 2010 Elsevier B.V. All rights reserved.