Kinetics of the reduction of fullgrown microelectrode silver particles by thiourea

Abstract

Kinetics of the title reaction (silver nano particles + thiourea) has been studied spectrophotometrically at 425 nm in presence of cationic and anionic micelles of cetyltrimethylammonium bromide and sodiumdodecyl sulphate, respectively. Silver nano size particles (yellow colour) were prepared by the reduction of silver nitrate with ascorbic acid in neutral aqueous media at 25°C. Various experiments were made to confirm the nature of yellow colour. Nano particles were found to be spherical in shape. The reaction proceeds through the fast adsorption of thiourea on the surface of the full grown microelectrode silver nano particles (FGME). The first-order kinetics shifts to zero-order at higher [thiourea].The observed results are discussed in terms of Langmuir-Hinshelwood kinetic model. Based on experimental results, a suitable mechanism has been proposed for the reduction of FGME silver nano particles.