Flower-like Ag Research Articles

Microwave-assisted synthesis of flower-like Ag–BiOCl nanocomposite with enhanced visible-light photocatalytic activity

Flower-like BiOCl and Ag–BiOCl nanocomposite have been successfully fabricated via a microwave irradiation process. The structure and morphology of the samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM). The photocatalytic property of the BiOCl and Ag–BiOCl nanocomposite was evaluated by photodegradation of Rhodamine B (RhB) under visible light illumination. Results of photodegradation tests reveal that the Ag–BiOCl nanocomposite has much better photocatalytic activity than pure BiOCl. The excellent photocatalytic activity can be ascribed to the high effective electron–hole separation which results in the significant improvement of the photocatalytic activity of BiOCl.

Seed-mediated approach for the size-controlled synthesis of flower-like Ag mesostructures

Flower-like Ag mesostructures with the sizes in the range of 200nm to 700nm have been synthesized via a simple seed-mediated approach. The size-tunable synthesis can be easily attained by adjusting the concentration of Ag seeds. The obtained Ag mesostructures are assembled by primary Ag nanosheets, which exhibit a flower-like architecture. None of surfactant was involved during the synthesis process, and thus, these Ag mesostructures hold the chemically clean surfaces. Compare to the previous approach for flower-like Ag mesostructures, the present method is not only simple and reliable, but also exhibits the advantages both in green procedure and size controllable. These flower-like Ag mesostructures reveal large surface area and can serve as highly efficient catalysis for the NaBH4 reduction of p-nitrophenol to p-aminophenol.

The Kinetically Dominated Overgrowth of Flower-Like Silver Nanostructures and its Application for Surface-Enhanced Raman Scattering

Herein flower-like silver nanostructures with different size and ratio of hexagonal close-packed (HCP) to face-centered cubic (FCC) phase were synthetized. By comparing with the results utilizing different surfactants, the growth process of Ag nanostructures has been investigated. Flower-like Ag nanoparticles containing numerous hot spots could serve as excellent surface-enhanced Raman scattering (SERS) substrates, and the Raman signal of Rhodamine 6G with the concentration as low as 10-6 M can be recognized.

Facile fabrication of hierarchically flowerlike Ag microstructure for SERS application

Hierarchically flowerlike Ag microstructure with uniform silver nanosheets as building blocks has been facilely prepared on a composite film surface via in situ reduction of Ag+ by a polyaniline component. The morphology of the as-prepared Ag microstructure is determined by the reaction duration, not the concentration of Ag+ in the reaction process. The complex geometry, rough surface, and interlaced nanosheets of the hierarchical Ag microstructure create interstitial sites and thus result in enhanced Raman signals.

Silver nanocrystals with special shapes: controlled synthesis and their surface-enhanced Raman scattering properties

Silver (Ag) nanoparticles with dendritic, urchin-like, flower-like and sphere-like shapes were controllably synthesized in aqueous hydrogen fluoride (HF) solution at room temperature. The shape of the Ag nanoparticles can be tuned from dendritic to urchin-like, flower-like and sphere-like by increasing the concentration of polyvinyl pyrrolidone (PVP, MW = 55 000) from 2 to 11 mM. As-synthesized Ag nanostructures were characterized by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX), and X-ray diffraction (XRD). The morphology-dependent surface-enhanced Raman scattering (SERS) of the as-synthesized Ag nanostructures was investigated. The results indicated that flower-like Ag nanostructure had higher SERS activity than other Ag nanostructures for 4-mercaptobenzoic acid (4-MBA) probe molecules. Moreover, the resultant substrate can be applied in the label-free detection of DNA with a sensitivity limit as low as 50 nM.

Silver nanocrystals of various morphologies deposited on silicon wafer and their applications in ultrasensitive surface-enhanced Raman scattering

Silver nanostructures with dendritic, flower-like and irregular morphologies were controllably deposited on a silicon substrate in an aqueous hydrogen fluoride solution at room temperature. The morphology of the Ag nanostructures changed from dendritic to urchin-like, flowerlike and pinecone-like with increasing the concentration of polyvinyl pyrrolidone (MW=55,000) from 2 to 10mM. The Ag nanostructures were characterized by transmission electron microscopy, high-resolution transmission electron microscopy, scanning electron microscopy, energy-dispersive X-ray, and X-ray diffraction. Through a series of time-dependent morphological evolution studies, the growth processes of Ag nanostructures have been systematically investigated and the corresponding growth mechanisms have been discussed. In addition, the morphology-dependent surface-enhanced Raman scattering of as-synthesized Ag nanostructures were investigated. The results indicated that flower-like Ag nanostructure had the highest activity than the other Ag nanostructures for Rhodamine 6G probe molecules.

Synthesis and characterization of coaxial silver/silica/polypyrrole nanocables

AbstractDouble‐shelled coaxial nanocables of silver nanocables with SiO2 and polypyrrole (PPy; Ag/SiO2/PPy) were synthesized by a simple method. The thickness of the outer PPy shell could be controlled by the amount of pyrrole monomer. The silver nanocables encapsulated in the interior of the hollow PPy nanotubes were obtained by the removal of the midlayer SiO2. By the silver‐mirror reaction, flowerlike Ag nanostructures could be formed on the surface of the Ag/SiO2/PPy multilayer nanocable. The application of the as‐prepared Ag/SiO2/PPy–Ag composites in surface‐enhanced Raman scattering (SERS) was studied with Rhodamine B (Rh B) as a probe molecule. We found that the composites could be used as SERS substrates and that they exhibited excellent enhancement ability. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Flowerlike Ag microparticles with novel nanostructure synthesized by an electrochemical approach

Three-dimensional (3D) flowerlike silver microparticles ( FSMPs) with novel nanostructure have been synthesized on the surface of a Pt film by a very simple, rapid and cost-effective electrochemical approach without introducing any template, surfactant or modification of electrode surfaces. The as-prepared FSMPs exhibit flowerlike morphologies and are built with many 2D nanoflakes as building blocks. The nanoflakes intersect mutually and have smooth surfaces, outwardly wavy edges and uniform thickness. The density of nanoflakes and the diameter of the FSMPs can be easily controlled by changing the electrodeposition time. A possible mechanism for electrochemical growth of the flake-built FSMPs is suggested on the basis of experimental results.