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Abstract: A facile one step method for the synthesis of wormlike silver nanoparticles has been carried out in methyl cellulose matrix. Synthesis is based on the reduction of AgNO3 by sodium borohydride (NaBH4) in aqueous methyl cellulose (MC). Synthesized nanoparticles are mostly mono disperse in size and their aggregation is controlled by varying the concentration of AgNO3. Silver nanoparticles are analyzed using transmission electron microscope (TEM), UV–vis spectroscopy and X-ray diffraction (XRD) technique. It has been found that the concentration of AgNO3 has a significant effect on the morphology of Ag nanostructures. Worm like nanostructures showed excellent catalytic activity in the borohydride reduction of p-nitrophenol compared to spherical shaped nanoparticles. [Copyright &y& Elsevier]

Abstract: Monodispersed sodium alginate (SA) stabilized silver nano bar and hydroxyl propyl methyl cellulose (HPMC) stabilized silver nano bar have been synthesized by photochemical method. The nanoparticles are characterized by UV–VIS–NIR spectroscopy, transmission electron microscopy (TEM) and selected area electron diffraction (SAED) study. Catalytic reduction of 4-nitrophenol (4-NP) by sodium borohydride in presence of nanoparticles is also evaluated. The kinetic data obtained by monitoring the change in UV–Vis absorption spectra of 4-NP are explained by Langmuir–Hinshelwood model. It is observed that the rate of reduction is higher in SA stabilized Ag nano bar than the HPMC stabilized Ag nano bar. [Copyright &y& Elsevier]

Abstract: Circular nanodiscs and truncated triangular shaped silver nanoplates have been synthesized through a seeding growth approach in polyvinyl pyrrolidone (PVP) matrix at room temperature. Seeds are prepared on reduction of silver nitrate (AgNO3) by sodium borohydride (NaBH4) and methyl cellulose (MC) is being used as encapsulating matrix. Colored silver sols are obtained as variable amounts of seeds are added to the growth solution containing silver nitrate, polyvinyl pyrrolidone (PVP) and ascorbic acid. Silver nanostructures are characterized using UV–vis spectroscopic and transmission electron microscopic (TEM) study. TEM studies reveal that particles are mostly circular disc and truncated triangular plate like as different amount of seeds are used in the growth solution. Simulation of UV–vis extinction spectra using discrete dipole approximation (DDA) method nicely explains the observed localized surface Plasmon resonance (LSPR) band of spherical and circular disc like silver nanoparticle. [Copyright &y& Elsevier]

Abstract: Spherical, hexagonal, triangular and bar shaped silver nanostructures have been synthesized at large scale in aqueous media using methyl cellulose (MC) as soft template. Synthesis is based on the reduction of Ag+ by hydrogen at different temperatures. Morphology of particles is mostly spherical at 60°C with an average diameter 4–8nm, whereas hexagonal, triangular and truncated hexagon silver nanostructures are obtained at 80°C. On the other hand bar shaped silver nanoparticles are formed as the reaction is carried out at 90°C. Silver nanoparticles are characterized using UV–Vis and TEM study. Formation of silver nanostructures of variable morphologies has been explained in terms of different shaped template formed by MC at different temperature due to its thermogelation properties. [Copyright &y& Elsevier]

Abstract: We report a method to synthesize silver nanoparticles of varying morphologies by a seeding growth approach at room temperature. Seeds are prepared by reducing silver nitrate with sodium borohydride, and trisodium citrate is used as capping agent. This citrate capped seed sol is added to the growth solution containing ascorbic acid, sodium dodecyl sulphate (SDS) and sodium hydroxide. Colour of the growth solution changes from colourless to pink and the surface plasmon resonance (SPR) shows two distinct bands, indicating the formation of anisotropically grown silver nanostructures. Synthesized silver nanoparticles are characterized by UV–vis spectroscopy, transmission electron microscopy (TEM) and X-ray diffraction (XRD) techniques. Silver nanoseeds are spherical in shape with diameter ranges from 8 to 16nm. On the other hand, a mixture of morphologies with shapes like triangular and hexagonal nanoplates, nanorods are obtained in the growth solution. XRD results suggest that the particles are crystalline in nature with face centered cubic (fcc) geometry. [Copyright &y& Elsevier]

Abstract: Solution-phase synthesis of nanometer-sized silver particles is reported by sodium borohydride reduction of AgNO3. Two isomeric dicarboxylates (sodium maleate and sodium fumarate) have been used as stabilizing agents. The dicarboxylate-stabilized silver nanoparticles are characterized by UV–vis spectroscopy, high-resolution transmission electron microscopy (HR-TEM) and fourier transform infrared (FT-IR) spectroscopy. A qualitative comparison is made between the UV–vis spectral characteristic of the SPR band and the simulated curve obtained from modified Mie''s theory. Silver nanoparticles prepared using these two isomeric dicarboxylates show intense fluorescence in the visible region. DFT with hybrid functional (B3LYP)-based frequency (IR) calculation of both the dicarboxylates and the respective nanoparticles are in good agreement with the experimental IR frequency. On the basis of this calculation a model has been proposed for the stabilization of silver nanoparticles by these two isomeric dicarboxylate anions. [Copyright &y& Elsevier]

Abstract: A method for the size-controlled synthesis of silver nanoparticles is proposed and described. Synthesis is based on the reduction of AgNO3 in aqueous SDS solution by hydrogen. These nanoparticles are poly-disperse in size and shape and their dimensions can be easily controlled in the range of 20 to 60 nm by varying the concentration of AgNO3. Silver nanoparticles are analyzed using transmission electron microscope (TEM) and UV–vis spectroscopic technique. A comparison between the experimentally observed UV–vis spectra and the simulated one obtained from the modified Mie''s theory, are made to understand the nature of shift of the SPR band. [Copyright &y& Elsevier]