Preparation Of Ag Nanoparticle Colloids Through Wet Chemical Reduction Method

Recently great interests have been aroused in the research of nanomaterials. Among them, nanometer metal materials have attracted particular attentions for their excellent catalytic performances, electromagnetic properties and optical properties. Due to their special volume effect, surface effect and quantum size effect, silver nanoparticles have been widely applied in antibacterial, medicine, superconductors, light and other aspects and have become promising novel materials.There are a variety of preparation methods for silver nanoparticles, among which wet chemical reduction has been widely used in the laboratory and industry. It facilitates large-scale production for easily controllable, relatively low equipment requirement, quick production and high yield. Silver nanoparticles with controllable nanometer size, good stability and dispersion have been prepared through controlling appropriate reaction conditions with silver nitrate as raw material,green product (glucose) as reducing reagent, Cetyltrimethyl Ammonium Bromide (CTAB) as dispersing agent. Silver nanoparticles colloids are characterized by means of X-ray Diffraction (XRD) and Transmission Electron Microscope (TEM). The XRD result shows that the products are silver nanoparticles and the crystals are face-centered cubic. The TEM results show that the main morphology of the silver nanoparticles is square, and other morphologies occur, such as rectangular and sphere-like.The results present that the morphology and size distribution of silver nanoparticles are greatly determined by the concentration of silver nitrate, glucose and CTAB, reaction temperature and reaction time.The optimized preparation conditions of square silver nanoparticles are as follows. The concentration of silver nitrate is 0.020mol/L and its volume is 5mL, the quantity of glucose is 0.0900g, the quantity of CTAB is 0.0680g, the reaction temperature is 50°C and the reaction time is 6h.