Preparation of silver nanoparticles by chemical reduction method

In the solution containing polyvinyl pyrrolidone (PVP), silver nitrate was reduced by the glucose, and silver particles were generated. The possible reaction process is discussed in this paper. Sodium hydroxide was used to enhance the reaction velocity. When the mole ratio of NaOH to AgNO3 was ranged from 1.4 to 1.6, the colloid kept stable and no Ag+ was traced. The particles and colloids were also analyzed by the X-ray diffraction (XRD), transmission electron microscopy (TEM) and UV-visible (UV-vis) spectrophotometer. The TEM photo indicated that with the increase in PVP, the particles dispersed better; and if the weight ratio of PVP to AgNO3 is no less than 1.5, the particles dispersed individually in a colloid form. The agglomeration of particles also was influenced by the mixing speed of the reactants. The XRD spectrums showed that the particles were silver simple substance if the reductant was sufficient and the mixing speed of the reactants was slow enough. (c) 2005 Elsevier B.V. All rights reserved.