Aqueous Solution Of AgNO3 Research Articles

Biosynthesis of silver nanoparticles by usingGanoderma-mushroom extract

Present study reports the biochemical synthesis of silver nanoparticles ( Ag -NPs) from aqueous medium by using the extract of medicinal mushroom Ganoderma, as a reducing and stabilizing agents. The Ag -NPs are prepared at room temperature by the reduction of Ag+to Ag in aqueous solution of AgNO3. The resultant particles are characterized by using UV-visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy and transmission electron microscopy (TEM) measurement techniques. The formation of Ag -NPs is confirmed by recording the UV-visible absorption spectra for surface plasmon resonance (SPR) where peak around 427 nm. The prominent changes observed in FTIR spectra supported the reduction of Ag+to Ag . The morphological features of Ag -NPs are evaluated from HRTEM. The spherical Ag -NPs are observed in transmission electron microscopy (TEM) studies. The particle size distribution is found to be nearly uniform with average particle size of 2 nm. The Ag -NPs aged for 15, 30, 60 and 120 days showed no profound effect on the position of SPR peak in UV-visible studies, indicating the protecting/capping ability of medicinal mushroom Ganoderma in the synthesis of Ag -NPs.

Synthesis of Ag@poly Composites with Different Morphologies

Ag@poly composites were synthesized by a facile method. The samples were characterized by scanning electron microscopy, X-ray diffraction, and infrared spectroscopy. Different concentrations and the molar ratios of AgNO3 aqueous solution and p-diamino-azobenzene, as well as the solvent, were used in the synthesis. Different morphologies of treelike structure, polygonal sheets, microrods, microtubes, and dendritic nanostructure were obtained. These results indicate that some synthesis parameters, such as concentrations of solutions, mole ratios of raw materials, and solvents, play important roles in the control of morphology.

Electrospun polyacrylonitrile nanofibers loaded with silver nanoparticles by silver mirror reaction.

The silver mirror reaction (SMR) method was selected in this paper to modify electrospun polyacrylonitrile (PAN) nanofibers, and these nanofibers loaded with silver nanoparticles showed excellent antibacterial properties. PAN nanofibers were first pretreated in AgNO3 aqueous solution before the SMR process so that the silver nanoparticles were distributed evenly on the outer surface of the nanofibers. The final PAN nanofibers were characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), transmission electron microscopy (TEM), TEM-selected area electron diffraction (SAED), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). SEM, TEM micrographs and SAED patterns confirmed homogeneous dispersion of the silver nanoparticles which were composed of monocrystals with diameters 20-30nm. EDS and XRD results showed that these monocrystals tended to form face-centered cubic single silver. TGA test indicated that the nanoparticles loaded on the nanofibers reached above 50wt.%. This material was also evaluated by the viable cell-counting method. The results indicated that PAN nanofibers loaded with silver nanoparticles exhibited excellent antimicrobial activities against gram-negative Escherichia coli (E. coli), gram-positive Staphylococcus aureus (S. aureus) and the fungus Monilia albicans. Thus, this material had many potential applications in biomedical fields.

Control of the phase composition of nanostructured silver iodide

Problems concerning the choice of synthesis technique and criterion that can be used to estimate the role of random factors in the formation process of nanosystems are discussed. Control of the nanostructured silver iodide phase composition is achieved by thermal modification. As the initial material we use AgI nanopowder obtained by an exchange reaction of aqueous solutions of AgNO3 and KI. The morphology of the surface of the samples has been studied using scanning electron microscopy. The phase composition is determined by X-ray phase analysis. The modification of the initial material has been carried out simultaneously with differential thermal analysis. Particular attention is paid to the entropy of the control, which characterizes the role of random factors by synthesizing nanosystems.

A facile formation of silver dendrites on indium tin oxide surfaces using electrodeposition and amperometric sensing of hydrazine

Silver dendritic structures have been prepared using constant potential deposition on indium tin oxide (ITO) electrodes from an aqueous solution of AgNO3 and KNO3 without any surfactants or structure directing agents. The applied potential is shown to be a crucial factor in the formation of dendrites. Depending upon the magnitude of the applied potentials, morphologies vary from polygons to dendrites. The shape evolution of the silver dendrites has been investigated by varying the deposition time and metal precursors. The mechanism of formation of dendrites is interpreted using the diffusion limited aggregation (DLA) model. The fractal dimensions of the dendrites calculated using the box counting algorithm are in agreement with those predicted by the DLA model. The Ag dendrites coated ITO electrodes exhibit excellent electrocatalytic activity toward oxidation of hydrazine in alkaline medium. The sensing of hydrazine is carried out with amperometry, where from the limit of detection and linear calibration range is deduced as 0.5μM and 100–1700μM respectively. The effect of ascorbic acid, urea, ethanol, glucose, K+, Cl−, Br− and I− ions as possible interfering agents in the detection of hydrazine is analyzed.

ChemInform Abstract: Hydrothermal Syntheses of Silver Phosphate Nanostructures and Their Photocatalytic Performance for Organic Pollutant Degradation.

AbstractSilver phosphate nanostructures including Ag5P3O10, Ag4P2O7/Ag3PO4, and Ag3PO4 are hydrothermally synthesized from aqueous solutions of AgNO3 and Na5P3O10 for different reaction times (autoclave, 120 °C, 0, 1.5, 3, 5, 8, and 12 h).

Rapid green synthesis of silver nanoparticles by aqueous extract of seeds of Nyctanthes arbor-tristis

The present study explores that the aqueous extract of the seeds of Nyctanthes arbor-tristis (aka night jasmine) is very efficient for the synthesis of stable AgNPs from aqueous solution of AgNO3. The extract acts as both reducing (from Ag+ to Ag0) and capping agent in the aqueous phase. The constituents in extract are mainly biomolecules like carbohydrates and phenolic compounds, which are responsible for the preparation of stable AgNPs within 20 min of reaction time at 25 °C using without any severe conditions. The synthesized silver nanoparticles were characterized with UV–Visible spectroscopy, FT-IR, XRD and SEM. UV–Vis spectroscopy analysis showed peak at 420 nm, which corresponds to the surface plasmon resonance of AgNPs. XRD results showed peaks at (111), (200), (220), which confirmed the presence of AgNPs with face-centered cubic structure. The uniform spherical nature of the AgNPs and size (between 50 and 80 nm) were further confirmed by SEM analysis.

ChemInform Abstract: High Adsorption Capacity for Cationic Dye Removal and Antibacterial Properties of Sonochemically Synthesized Ag2WO4 Nanorods.

AbstractThe title nanorods with an average diameter of 15—25 nm and a surface area of about 115 m2/g are synthesized by irradiation of an aqueous solution of Na2WO4 and AgNO3 under air for 1.5 h with high intensity ultrasonic radiation at 40 kHz.

A ROLE OF PROTEINS OF THE OUTER MEMBRANE OF Shewanella oneidensis MR-1 BACTERIA IN FORMATION AND STABILIZATION OF SILVER SULFIDE NANOPARTICLES

Preparations of Ag 2 S nanoparticles obtained in equimolar AgNO3 and Na2S2O3 aqueous solutions in the presence of Shewanella oneidensis MR-1 bacteria cells have been shown to be stable in aqueous solutions. Proteins absorbed on the surface of these nanoparticles were identified for the first time by the MALDI TOF/TOF method. Among them, multi-heme cytochromes MtrC and OmcA, as well as a MtrB membrane protein porin that forms a complex with these cytochromes on the outer cell membrane were detected. It was shown that in the absence of the cells, an insoluble precipitate consisting of agglomerated Ag 2 S nanoparticles with broad size distribution was formed. The role of the identified proteins in the mechanism of the formation and stabilization of the Ag 2 S nanoparticles in this system is discussed.

Visible-light-driven Ag/AgCl plasmonic photocatalysts via a surfactant-assisted protocol: enhanced catalytic performance by morphology evolution from near-spherical to 1D structures.

Ag/AgCl-based plasmonic photocatalysts have received much attention as emerging visible-light-driven photocatalysts, wherein those characterized by 1D morphology have aroused great expectations. Most of the current existing protocols for the fabrication of 1D materials, however, suffer from either multistep tedious synthesis processes or the requirement of rigorous experimental conditions. A one-pot fabrication method feasible under ambient conditions is strongly desired. By means of a surfactant-assisted protocol, we report herein that Ag/AgCl structures of near-spherical and 1D morphology could be controllably produced. We show that near-spherical Ag/AgCl species could be produced immediately after dropping an AgNO3 aqueous solution into an aqueous solution of cetyltrimethylammonium chloride (CTAC) surfactant under stirring. Interestingly, we show that these initially formed near-spherical species could automatically evolve into 1D Ag/AgCl fibers simply by extending the stirring time under ambient conditions. In our new protocol, CTAC works not only as a chlorine source but also as a directing reagent to assist the formation of 1D Ag/AgCl structures. Moreover, we demonstrate that compared to near-spherical structures, our Ag/AgCl fibers could display boosted catalytic performances towards the photodegradation of the methyl orange pollutant under visible light irradiation. Our work might launch an easy method for the construction of fibrous Ag/AgCl architectures of superior photocatalytic reactivity, and it also provides deep insights into the surfactant-assisted synthesis.

Photocatalytic growth and plasmonic properties of Ag nanoparticles on TiO2 films

Abstract

Liquid-phase reactions induced by atmospheric pressure glow discharge with liquid electrode

We experimentally investigated some of the initial reactions in a liquid induced by electron or positive-ion irradiation from an atmospheric-pressure dc glow discharge in contact with the liquid. We used an H-shaped glass reactor to observe the effects of electron irradiation and positive-ion irradiation on the liquid-phase reaction separately and simultaneously. Aqueous solutions of NaCl, AgNO3, HAuCl4, and FeCl2 are used as the electrolyte. Solutions of AgNO3 and HAuCl4 are used for the generation of Ag and Au nanoparticles, respectively. Solution of FeCl2 is used for the generation of ferromagnetic particles. Experimental results showed that electron irradiation of the liquid surface generates OH− in water and that positive-ion irradiation of the liquid surface generates H+ in water even without the dissolution of gas-phase nitrogen oxide. A possible reaction process is qualitatively discussed. We also showed that the control of reductive and oxidative environment in the liquid is possible not only by the gas composition for the plasma generation but also by the liquid composition.

Metal-impregnated zeolite Y as efficient catalyst for the direct carbonation of glycerol with CO2

Metal-impregnated zeolite Y catalysts were prepared by treatment of a NaY zeolite with an aqueous solution of AgNO3, Zn(NO3)2 and SnCl2, followed by water evaporation. The materials were then calcined in air at 450°C and evaluated in the reaction of CO2 with glycerol at 180°C for 3h at 100Bar. The parent NaY zeolite was inactive under these conditions, but the metal-impregnated zeolites, as well as the calcined salt precursors, showed yields of glycerol carbonate up to 5.8%. The TON of the zeolite catalysts were significantly higher than that of the calcined salts, suggesting the formation of a highly active metal oxide phase at the external surface of the zeolite.

Substrate-independent sequential deposition process to obtain the lotus effect based on mussel-inspired polydopamine

A substrate-independent route to achieve the lotus effect on a variety of substrates is proposed based on mussel-inspired polydopamine (PDA), and was tested on titanium alloy, polypropylene and silicon substrates. The substrates were firstly coated with PDA and then sequentially transferred to aqueous CuCl2 and AgNO3 solutions for copper and silver deposition. Finally, the samples were passivated by the low-surface-energy molecules of 1-dodecanethiol, and surface superhydrophobicity (contact angle>160°; sliding angle between 1° and 2°) could be obtained. Due to the strong adhesion of PDA to a wide range of materials, it is expected that this deposition process can be applied to a variety of other substrates including metal, polymer, and inorganic-nonmetallic materials.

Superhydrophobic surfaces on diverse metals based on ultrafast sequential deposition of silver and stearic acid

In the presence of NaF, silver (Ag) was galvanically deposited onto aluminum (Al) substrate quickly (typically 10s) from dilute aqueous AgNO3 solution. Subsequent immersion into ethanolic solution of stearic acid (SA, for 30s) rendered Al superhydrophobic. The deposition and morphological evolution of Ag were investigated in detail. It was found that NaF was indispensable to initiate the Ag galvanic deposition by dissolving the barrier oxide layer. Moreover, as reaction time prolonging, surface morphology and surface wettability varied synchronously. This strategy to fabricate superhydrophobic surface (coded as SHS) was also applicable to many other metals, such as Fe, Co and Mo with oxide passivation layer (NaF was needed) or Mg, Zn, Sn, Pb, and Cu with no apparent oxide passivation layer (NaF was not needed). In summary, the strategy to fabricate SHS based on Ag deposition and SA modification was quite impressive for its time-saving benefits and wide substrate applicability.

Chemical reactions in liquid induced by atmospheric-pressure dc glow discharge in contact with liquid

We experimentally investigated some of the initial reactions in a liquid induced by electron or positive-ion irradiation from an atmospheric-pressure dc glow discharge in contact with the liquid. Aqueous solutions of NaCl, AgNO3, and HAuCl4 are used as the electrolyte. We measured the pH and conductivity in the liquid at approximately 1 cm below the solution surfaces. OH radical generation in the liquid was observed by a chemical probe method. Experimental results showed that electron irradiation of the liquid surface generates OH− in water and that positive-ion irradiation of the liquid surface generates H+ in water even without the dissolution of gas-phase nitrogen oxide. A possible reaction process is qualitatively discussed. In particular, the contribution of charge transfer collision between impinging low-energy positive ions and water molecules to the ionic species in the liquid is used to explain the overall tendency of the experimental results.

Optical engineering of uniformly decorated graphene oxide nanoflakes via in situ growth of silver nanoparticles with enhanced plasmonic resonance.

A nanocomposite of silver-nanoparticle-decorated graphene oxide (GO-Ag NPs), enhanced by the surface plasmon resonance (SPR) effect, improved the performance of polymer solar cells (PSCs). The GO-Ag NPs were fabricated in situ via ultraviolet (UV) irradiation (254 nm) of GO and an aqueous solution of AgNO3. The photoexcited GO accelerated reduction of Ag(+) ions into silver nanoparticles (Ag NPs) upon UV irradiation, and the Ag NPs spontaneously deposited on the GO nanoflakes because the numerous functional groups on GO enable efficient adsorption of Ag(+) ions and Ag NPs via electrostatic interactions. The strong coupling between the SPR effect of GO-Ag NPs and incident light offers the probability of improved light absorption and corresponding exciton generation rate with enhanced charge collection, resulting in significant enhancement in short-circuit current density and power conversion efficiency (PCE). Therefore, the PCE of PSCs based on poly[4,8-bis(2-ethylhexylthiophene-5-yl)-benzo[1,2-b:4,5-b]dithiophene-2,6-diyl]-alt-[2-(2-ethylhexanoyl)thieno[3,4-b]thiophen-4,6-diyl] and [6,6]-phenyl C71-butyric acid methyl ester has been substantially elevated to 7.54% from 6.58% by introducing GO-Ag NPs at the indium tin oxide/poly(3,4-ethylenedioxythiophene):polystyrene sulfonic acid interface. In addition, the excellent properties of GO-Ag NPs, including its simple preparation, processability in aqueous solution, cost-effectiveness, and sustainability, make it suitable for the roll-to-roll manufacturing of PSCs.

Catalytic Cracking of Supercritical n-Dodecane over Wall-Coated Nano-Ag/HZSM-5 Zeolites

A series of Ag modified zeolites were prepared by incipient impregnation of nano-HZSM-5 with AgNO3 (0.5–2.0 wt %) aqueous solutions. It was found that the ion-exchange and impregnation effect both existed in this impregnation process, resulting in the formation of various silver species which altered the zeolite acid properties. The wall-coated nano-Ag/HZSM-5 zeolites were prepared on the inner surface of 304 stainless steel tubes though the washcoating method. Catalytic cracking of supercritical n-dodecane (4 MPa, 550 °C) was used to examine the catalytic activities of the prepared catalytic coatings. It is found that the modified samples with 1.0% Ag showed higher conversion (up to 1.50 times) than the parent one because of the dehydrogenation effect of silver species and that the overloaded (for example, 2.0 wt %) samples show lower performances ascribing to the blockage of diffusion pores by the silver species.

Photocatalytic O2 evolution from water over Zn–Cr layered double hydroxides intercalated with inorganic anions

Zn–Cr layered double hydroxides (LDHs) intercalated with inorganic anions (CO32−, Cl−, SO42− and NO3−) were synthesized by the co-precipitation method and the anion exchange process. The photocatalytic activity of the LDHs was studied by O2 evolution from aqueous solution of AgNO3 as a sacrificial agent. All the prepared LDHs showed photocatalytic activity under either UV and/or visible light irradiation. Besides, the interlayer anions affected the photocatalytic activity of the LDHs. After irradiation, Ag particles were formed on the LDHs by accepting the electrons generated during the photocatalytic reaction.

Specific Interactions of Ag+ Ions with Anionic Polyacrylate Chains in Dilute Solution

A detailed light scattering investigation is presented on dilute solutions of two long-chain sodium polyacrylates (NaPA) in the presence of monovalent Ag+ ions in 0.01 M NaNO3 aqueous solution at a pH of 9. The relevance for the investigation is based on two features: (i) despite its monovalency, Ag+ is expected to exhibit a much more complex interaction pattern with NaPA than salts based on alkaline cations do; (ii) aqueous solutions of AgNO3 nucleate Ag–nanoparticle formation in the presence of NaPA under UV light, which may be modulated by the solution behavior. Our study revealed the following results. Addition of a low amount of Ag+ ions leads to an aggregation of PA-chains without considerable coil shrinking. At a ratio of silver ions per monomer of 0.001 ≤ [Ag+]/[COO–] ≤ 0.05, combined static and dynamic light scattering (SLS/DLS) suggests formation of homogeneous low density aggregates. Further increase of the Ag+ ion concentration results in a formation of dense unstable aggregates. At ratios of ...