Silver nanoparticles: preparation, characterization, and kinetics (original) (raw)

Preparation and characterization of silver nanoparticles by chemical reduction method

Colloids and Surfaces B-biointerfaces, 2011

Silver nanoparticles were prepared by the reduction of AgNO 3 with aniline in dilute aqueous solutions containing cetyltrimethlyammonium bromide, CTAB. Nanoparticles growth was assessed by UV-vis spectroscopy and the average particle size and the size distribution were determined from transmission electron microscopy, TEM. As the reaction proceeds, a typical plasmon absorption band at 390-450 nm appears for the silver nanoparticles and the intensities increase with the time. Effects of [aniline], [CTAB] and [Ag + ] on the particle formation rate were analyzed. The apparent rate constants for the formation of silver nanoparticles first increased until it reached a maximum then decreased with [aniline]. TEM photographs indicate that the silver sol consist of well dispersed agglomerates of spherical shape nanoparticles with particle size range from 10 to 30 nm. Aniline concentrations have no significant effect on the shape, size and the size distribution of Ag-nanoparticles. Aniline acts as a reducing as well as adsorbing agent in the preparation of roughly spherical, agglomerated and face-centered-cubic silver nanoparticles.

Silver nanoparticles: New synthesis, characterization and photophysical properties

Materials Chemistry and Physics, 2007

In this paper, we report a new solution phase synthetic route to prepare silver(0) nanoparticles and their optical properties. The Ag(0) nanoparticles were prepared by reduction of AgNO 3 using t-BuONa-activated NaH in tetrahydrofuran at low temperature. The resulting t-BuONa-stabilized silver nanoparticles were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD) and UV-vis spectroscopy. The cubic face centered Ag(0) particles produced present a tight size distribution with an average radius of 3.3 ± 0.7 nm. The silver nanoparticles dispersed in tetrahydrofuran exhibit a broad and structured fluorescence band when exposed to oxygen. This result is corrolated with a red shift of the surface plasmon absorption band. This process has been attributed to production of charged nanoclusters, Ag m 2+ , produced by consecutive oxidation then chemisorption of Ag + onto metal surface.

Silver Nanoparticles: Synthesis, Characterization and Applications

InTech eBooks, 2018

Day by day augmenting importance of metal nanoparticles in the versatile fields like, catalyst, electronic, magnetic, mechanic, optical optoelectronic, materials for solar cell and fuel cell, medical, bioimaging, cosmetic, ultrafast data communication and optical data storage, etc, is increasing their value. Nanoparticles of alkali metals and noble metals (copper, silver, platinum, palladium, and gold, etc.) have a broad absorption band in the visible region of the electromagnetic spectrum of light, because the solutions of these metal nanoparticles show the intense color, which is absent in their bulk counterparts as well as their atomic level. The main cause behind this phenomenon is attributed to the collective oscillations of the free conductive electrons that are induced by an interaction with electromagnetic field. The whole incidence is known as localized surface plasmonic resonance. Out of these, we have selected the silver nanoparticles for the studies. In this article, we will discuss the synthesis, characterization, and application of the silver nanoparticles. Future prospective and challenges in the field commercialization of the nanosilver is also discussed.

Silver Nanoparticles: Green Route, Stability and Effect of Additives

Journal of Biomaterials and Nanobiotechnology, 2011

Colloidal silver nanoparticles were prepared by reducing silver nitrate with oxalic acid in presence of cetyltrimethylammonium bromide (CTAB). The synthesized silver particles show an intense surface plasmon band in the visible region. The work reported in this paper describes the effect of concentration of various additives (NaCl, NaBr, NaNO 3 , Na 2 SO 4 and NaH 2 PO 4) and ammonia on the growth and stability of Ag-nanoparticles. In all the cases the rate decreases as the [electrolytes] or [ammonia] increases. The nature, polarizability and coordinating ability of the anions play vital roles for nucleus formation and the growth process, which subsequently form different size particles. Transmission electron microscopy, selected areas electron diffraction, and UV-visible spectroscopy have been employed to characterize Ag-nanoparticles. The effect of the following variables on the particle size and size distribution was investigated: the [oxalic acid], [CTAB] and [Ag + ]. The nanoparticles are stable in NaNO 3 and NaH 2 PO 4 solutions; but NaCl, NaBr and Na 2 SO 4 causes their aggregation.

Current Research on Silver Nanoparticles: Synthesis, Characterization, and Applications

Journal of Nanomaterials

Over the past couple of decades, nanomaterials have advanced the research in materials; biomedical, biological, and chemical sciences; etc., owing to their peculiar properties at the nanoregime compared to their bulk composition. Applications of nanoparticles in the fields like medicine and agriculture have been boosted due to the development of different methodologies developed to synthesize specific shapes and sizes. Silver nanoparticles have tunable physical and chemical properties, so it has been studied widely to improve its applicability. The antimicrobial properties of Ag NPs are finding their application in enhancing the activity of drugs (like Amphotericin B, Nystatin, Fluconazole) and composite scaffolds for controlled release of drugs and targeted delivery of drugs due to their low toxicity and biocompatibility. Similarly, their surface plasmon resonance property makes Ag NPs a top-notch material for developing (bio)sensors, for instance, in surface-enhanced Raman spectro...

Formation and stability study of silver nano-particles in aqueous and organic medium

−Colloidal silver nanoparticles were obtained by chemical reduction of silver nitrate in water and organic solvent with sodium borohydride. The effects of oxidant, reducing agent, stabilizer, and temperature, during the growth of silver nanoparticles were discussed. As the reaction proceeded in aqueous medium a characteristic plasmon absorption peak between 390-420 nm appeared as presence of silver nanoparticles. The peak intensities and shifting (blue or red) were altered in accordance with some applied factors. The formed silver nanoparticles were found to be with particles size range from 3 to 20 nm. The change rates of Ag + ions to Ag 0 in aqueous and organic solvent are strongly temperature dependent, although reduction can take place at room temperature. The silver nano-colloid with negative zeta potential also has been confirmed to be more stable. Obtained nanoparticles were characterized by UV-vis spectropho-tometer, particle analyzer for zeta (ζ) potential, polydispersity index (PDI), and transmission electron microscope (TEM).

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.

The study on the stability of silver nanoparticles by using simple spectrophotometric method

2012

Silver nanoparticles using different concentrations of AgNO3 precursor were successfully synthesized using sodium borohydride as the reducing and capping agent. This study investigated the stability of silver nanoparticles at two different silver nitrate concentrations using a simple UV-Vis Spectroscopic technique. The UV-Vis spectroscopy confirmed the formation of silver nanoparticles by exhibiting the typical surface plasmon absorption maxima ranging from 390-408 nm for higher (10-3M) AgNO3 concentration, whereas for lower (10-4M) AgNO3 concentrations, we observed variation in the SPR band which can be attributed to aggregation of Ag NPs. During this study, we concluded that nanoparticles at lower AgNO3 concentration were much more stable than nanoparticles at higher AgNO3 concentration. The synthesized Ag NPs may have many potential applications such as antibacterial, antifungal, catalyst and sensor etc.

Optical and structural studies of silver nanoparticles

Radiation Physics and Chemistry, 2004

Gamma radiolysis method was used to prepare polyvinyl alcohol (PVA) capped silver nanoparticles by optimizing various conditions like metal ion concentration and polymer (PVA) of different molecular weights. The role of different scavengers was also studied. The decrease in particle size was observed with increase in the molecular weight of capping agent. g-radiolytic method provides silver nanoparticles in fully reduced and highly pure state. XRD (X-ray diffraction) technique confirmed the zero valent state of silver. Optical studies were done using UV-visible spectrophotometer to see the variation of electronic structure of the metal sol. Transmission Electron Microscopic (TEM) studies reveal the fcc geometry. The TEM show clearly split Debye-Scherrer rings. The d values calculated from the diffraction ring pattern are in perfect agreement with the ASTM data. Ag particles less than 10 nm are spherical in shape, whereas the particles above 30 nm have structure of pentagonal biprisms or decahedra, referred to as multiply twinned particles.

Biological Sciences SYNTHESIS AND CHARACTERIZATION OF SILVER NANOPARTICLES

2014

Silver nanoparticles exhibit new optical properties, which are observed neither in molecules nor in bulk metals. In the present study silver nanoparticle colloid was produced by chemical reduction method of silver salt (silver nitrate AgNO3) solution. The silver nanoparticles were characterized by using UV-VIS spectrometer and Scanning Electron Microscope (SEM). The Surface Plasmon Resonance peak in absorption spectra of silver colloidal solution showed an absorption maximum at 450 nm which indicated formation of silver nanoparticles. The size range 44nm to 56.55nm of silver nanoparticles was determined by using Scanning Electron Microscope (SEM). The absorbance range of prepared silver nanoparticles solution was checked on 1 st day, 5 th day, 18 th day and on 30 th day. There was no obvious change observed in peak position for 30 days, depicting the stability of Silver nanoparticles.