Colloidal Synthesis and Structural Characterizations of Silver Nanoparticles by using Wet Chemistry (original) (raw)
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Preparation of colloidal silver nanoparticles and structural characterization
2013
In this paper, we prepare silver nanoparticles colloids by using polyvinyl pyrrolidone (PVP) of four different molecular weights (MW = 10000, 29000, 40000, 55000) as a protective agent, dextrose as reduction agent and by adding urea which produce intermediates AgOCN and Ag2CO3. Results indicated that PVP effects against agglomeration would depend to a great extent on the hydroxide and urea concentrations used in the reaction medium. When NaOH was dominant, the reaction rate was very fast and hence only PVP with large molecular weight produced small silver colloids of sizes around 20 nm. On the other hand, when urea was dominant, the reaction path was significantly changed and slowed down as well; under this circumstance, PVP with MW of 10000 offered the best protection against agglomeration, it produced silver colloids of only 26 nm. A part of our silver nanoparticles was extracted as powder, to be characterized by XRD, and another part was deposited on glass substrates, by spin-coa...
Colloidal Synthesis of Silver Nano Particles
Asian Journal of Chemistry
Silver nanoparticles exhibit new optical properties, which are observed neither in molecules nor in bulk metals. One example is presence of absorption band in visible light region. A class of materials in which two or more phases (solid, liquid or gas) of same or different materials co exists with at least one dimension less than a micrometer is known as colloids. Nanomaterials are a subclass of colloids, in which one of the dimensions of colloids is about 1 to 100 nanometer range. In the present work, Ag nanoparticles were synthesized by silver salt (AgNO 3) reduction with sodium citrate and then characterized using UV-Visible spectroscopy and SEM. UV-Visible absorption results confirmed formation of silver particles prepared and SEM indicates the size in nanometer (nm) range.
Establishment of optimum conditions for preparation of silver nanoparticles
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Synthesis and characterization of silver nanoparticles
2007
Silver nanoparticles have received considerable attention due to their attractive physical and chemical properties. The surface plasmon resonance and large effective scattering cross section of individual silver nanoparticles make them ideal candidates for molecular labeling, where phenomena such as surface enhance Raman scattering (SERS) can be exploited. In addition, silver nanoparticles have recently been shown to be a promising antimicrobial material. In the present research silver colloid was produced by sodium citrate reduction. The colloidal silver was incorporated by dip-coating to the polymer substrate. X-Ray Fluorescence Spectroscopy (XRF), Atomic force microscopy (AFM), ultraviolet-visible spectroscopy (UV-VIS ) and SERS indicate that the produced structures include metallic crystalline silver nanoparticles. The surface plasmon resonance peak in absorption spectra of silver particles showed an absorption maximum at 420-500 nm. The silver - polymer nanocomposites structures with selective light properties as a result of plasmon resonance shifting in the UV-VIS wavelength region were produced.
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...
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...
Single step morphology-controlled synthesis of silver nanoparticles
Silver nanoparticles having different size and plasmon resonances were synthesized through a single step aqueous based method. The current procedure was based on the reduction of silver ions by ascorbic acid in the presence of sodiumborohydride and trisodium citrate. Triangular colloidal nanoparticles having different plasmon resonances (and hence different size and colours) were synthesized by varying only the concentration of ascorbic acid. These nanoparticles were found to be stable without using any surfactants or polymers. This study revealed a strong correlation between particle growth and concentration of constituent chemicals. Crystallinity and phase purity of the silver samples were investigated through powder X-ray diffraction studies (XRD). Absorption spectra of various silver particles were recorded using UV/Vis/NIR spectrometer. Morphological analysis was performed using transmission electron microscopy (TEM) and average edge lengths of nanoparticles were also calculated.
A simple and effective route for the synthesis of nano-silver colloidal dispersions
Journal of the Chinese Institute of Chemical Engineers, 2008
In this work we develop a simple method to synthesize nanosized Ag colloids with the addition of urea which produce intermediates AgOCN and Ag 2 CO 3 before the formation of silver. These intermediates are beneficial to obtaining high conversions of narrow size distributions of silver colloids from this synthesis process. At the molar ratio of [Urea]/[Ag + ] = 4, [NaOH]/[Ag + ] = 0.8, the weight ratio of PVP/AgNO 3 = 1 g/g, using dextrose as a reducing agent and a reaction temperature of 70 8C, we obtain silver colloids of average size 22 nm with a standard deviation of 4.7 nm after separation and washing procedures. The conversion under these conditions was nearly complete at about 98%. After a thorough washing procedure, the purity of silver colloids is up to 94.4% and its dried film is electrically conductive at room temperature. The electrical resistivity reached 4.5 Â 10 À6 V cm after 250 8C heating for 30 min.
SYNTHESIS AND CHARACTERIZATIONS OF SILVER NANO PARTICLES USING CHEMICAL REACTION METHOD
In the present investigation colloidal silver nanoparticles was prepared by chemical reaction method from silver nitrate (AgNO3) and sodium citrate (Na3C6H5O7) in water. The preparation method were achieved at three levels of temperature (100, 150 and 200℃) the produced silver nanoparticles characterize by UV-vis Visible Spectroscopy, Scanning Electron Microscopy (SEM) and Particle Size analyzer the result of particle size analyzer show that their size distribution to lie in the range of (58.9-202) nm. The results show that silver nanoparticles are 58.9, 76.4 and 202 nm at temperatures of (100, 150, 200) ℃, respectively can be produced.
Synthesis and Characterisation of Silver Nanoparticles in Different Medium
Silver nanoparticles were synthesized in different alcoholic medium such as ethylene glycol and n-butyl alcohol by solvothermal method. The nanoparticles have been successfully synthesized by reducing silver nitrate with the above solvents in the presence of trioctyl phosphine oxide (TOPO) as the capping agent at room temperature for 1 h. Electron microscopy, X-ray diffraction, and absorption spectra have been used to investigate the products, and the mechanism is proposed to interpret the controlled synthesis of the products. The results indicate that this approach provides a versatile route to prepare silver nanowires and nanoparticles with controllable diameters. The formation of nano products by this method is rapid, simple and stable.