Room temperature, water-based, microreactor synthesis of gold and silver nanoparticles (original) (raw)
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Synthesis and optical properties of colloidal gold nanoparticles
Journal of Physics: Conference Series, 2009
Colloidal gold nanoparticles (spheres) have been prepared from HAuCl4 containing aqueous solution by using X-ray irradiation and by chemical reduction method. Gold nanorods were synthesized according to the seed-mediated growth method. The colloidal gold nanoparticles were characterized by using transmission electron microscopy, X-ray diffraction, and UV-VIS absorption spectroscopy. It was found that the concentration of the precursors affects the size of the nanoparticles. In the chemical reduction approach the size of nanoparticles can be controlled by varying amount of trisodium citrate, but in the photochemical method the size of nanoparticles can been controlled by varying the ratio of HAuCl4 to TX-100 and X-ray irradiation duration. Gold nanorods have been synthesized according to the seed-mediated growth method with two steps. The effect of silver acetate and CTAB on formation of gold nanorods has been studied.
2016
Unique optical and physical behaviour of nanoparticles compared to corresponding bulk materials has gain considerably interest and the research in synthesizing and application of nanoparticles has expanded rapidly over a last decade. This present study reported on the well-dispersity synthesis of nano-size material via chemical reduction of silver nitrate (AgNO3) by sodium borohydride (NaBH4) in an aqueous medium. In this study, there are two parameters that were manipulated which are temperatures; varied from 25 °C until 90 °C and concentration of sodium chloride (NaCl) that was varied from 0.0mM to 30.0 mM respectively. The UV-Vis analysis of silver nanoparticles shows maximum peak were determined at the range of 404nm-410 nm which is the characteristic of Ag particles. Meanwhile, the morphology of as-synthesized silver nanoparticles (AgNPs) that investigated by using Field Emission Scanning Electron Microscopy (FESEM) reveals a spherical particles size with the size range of 20 n...
Influence of Reagents on the Synthesis Process and Shape of Silver Nanoparticles
Materials
The aim of this study was to prepare the silver nanoparticles (AgNPs) via chemical reduction and analyze the impact of used reduction agents: sodium borohydride (NaBH4), trisodium citrate (TSC), polyvinylpyrrolidone (PVP), and hydrogen peroxide (H2O2) on the reduction rate of Ag+ ions to Ag0, and on nanoparticles shape. It was proven that combinations of reduction agents dramatically influence the synthesis rate of AgNPs and the color of solutions, which depends on the shape and size of nanoparticles. NaBH4, TSC, and PVP showed good reduction power. In particular, TSC proved to be a key factor influencing the shape of AgNPs. The shape of nanoparticles influences the color of colloidal solutions. Yellow solutions, where UV-vis absorbance maxima (ABSmax) are in the wavelength interval 380–420 nm, contain spherical particles with a mean size of 25 nm, whereas the blue shift of ABSmax to wavelengths higher than 750 nm indicate the presence of triangular nanoparticles (size interval 18–1...
Synthesis and characterization of silver nanoparticles by chemical reduction method
Colloids and Surfaces B-biointerfaces, 2011
Nanoparticles, compared to micro particles have distinctly different properties and advanced characteristics. Silver nanoparticles are one of the metal nanoparticles which has varied and different properties when compared to other material. Silver nanoparticles have received considerable attention due to their attractive physical and chemical properties, Especially suitable for sensor applications, while there are different methods for synthesis of silver nanoparticles, the most popular preparation of Ag nanoparticles is by chemical reduction. Silver nitrate is taken as the metal precursor and sodium borohydride as a reducing agent. This preparation is simple, but the great care must be exercised to make stable particles. Here silver nanoparticles are synthesized by the chemical reduction of silver nitrate. These silver nanoparticles are characterized by the different techniques like UV-Vis spectroscopy for the structural characterization, SEM to know the size morphology and composition of nanoparticles, XRD to know the lattice parameters. The UV-Vis spectroscopy revealed the formation of silver nanoparticles by exhibiting the typical surface Plasmon absorption maxima at a wavelength of 420nm as observed. From the UV Vis spectrum the agglomerated grain diameter size is estimated around 60 nm. The peaks in the XRD pattern are in good agreement with the standard values of the face-centered-cubic form of metallic silver (ICCD-JCPDS card no.04-0783) and no peaks of other impurity crystalline phrases are detected. The energy dispersive spectroscopy (EDS) of the nanoparticles dispersion confirms the presence of elemental silver in nanoscale.