Aqueous Silver Nitrate Solution Research Articles

Silver nanoparticle–decorated PANI/reduced graphene oxide for sensing of hydrazine in water and inhibition studies on microorganism

Silver nanoparticle–modified polyaniline (PANI)/rGO nanocomposite was synthesized by interfacial polymerization under static condition. In this method, the aqueous solution of graphene oxide and silver nitrate was allowed to react with aniline dimer present in the organic phase (dichloromethane) the polymerization reaction takes place at the interface. The resulting silver nanoparticle–embedded graphene sheets was isolated and then characterized with various analytical methods. The electrocatalytic oxidation of hydrazine and the antibacterial activity of the composite film were investigated. Enhanced electrocatalytic oxidation was noted and then exploited for the determination of hydrazine in water samples. The electrochemical behavior of AgNP@PANI-rGO nanocomposite was studied by cyclic voltammetry and electrochemical impedance spectroscopy (EIS). Amperometry method was employed for quantitative electrochemical detection of hydrazine. A linear range of the calibration plot was obtained in the concentration range from 0.4 to 2.2 μM with the correlation coefficient 0.9900, and the limit of detection was found to be 70 nM. Antibacterial activity of nanocomposite was investigated against Gram-positive and Gram-negative microorganisms, and the composite shows excellent inhibitory action.

Synergistic effect between Ag and Cu for the observation of huge SERS signal of photochemically prepared polypyrrole. Application to toxic volatile organic compounds sensing

Polypyrrole (PPy) film was photochemically synthesized in an aqueous silver nitrate solution on a copper plate which has undergone a prior SERS-activation procedure according to the well-known ORC roughening protocol. Elemental and vibrational analyses by X-ray photoelectron (XPS) and infrared (IR) spectroscopies revealed the incorporation of both silver particles and nitrate doping anions into the polymer matrix. Furthermore, scanning electron microscopy (SEM) morphological characterization of the obtained silver particles highlighted leaf-shaped crystals whose growth follows a fractal geometry. The combination of this growth mode with the rough nature of the copper surface gives lies at the origin of a huge SERS effect whose enhancement factor was evaluated at 200 in comparison with PPy electrosynthesized on platinum. On the other hand, the PPy-Ag composite exhibited very interesting sensing properties with significant reproducible changes in the polymer electrical resistance when subjected to gas emissions of both ammonia and acetone. Given these encouraging results, potential sensing applications of the composite polymer would be conceivable in various industrial domains.

Eco-friendly polymer succinate capping on silver nano-particles for enhanced stability: a UV-Vis and electrochemical particle impact study

A facile green method is used to synthesize silver nanoparticles (Ag Nps) in one minute. The colloidal stability of two types of Ag Nps (namely, hydroxypropylcellulose-succinate (HPC-Suc) capped silver nanoparticles (Ag Nps@suc) and citrate-capped silver nanoparticles (Ag Nps@cit)) is investigated using UV-Vis spectrometry and electrochemical particle impacts “nano-impacts” measurements. Ag Nps@suc were newly synthesized by simply mixing aqueous solutions of HPC-Suc and silver nitrate and exposure to sunlight. The growth of Ag Nps was controlled by adjusting the exposure time to sun light. Local surface plasmon resonance (LSPR) study was conducted using UV-Vis spectrophotometer. The surface morphology, size, elemental analysis and composition of Ag NPs@suc was determined by SEM-EDX, while ATR-FTIR was used to assess any type of chemical reactions between the precursors. For stability and size distribution measurements zeta-potential (ZP), dynamic light scattering (DSL) and anodic particle coulometry (APC) were performed. The as-prepared Ag Nps@suc exhibited a narrow size distribution with an average diameter of 20 nm. Nps sizing using particles electrochemical impacts method is consistent with SEM and DLS techniques. The results show that Ag Nps@cit are prone to relatively rapid clustering upon addition of electrolyte (100 mM K2SO4). On the other hand, Ag Nps@suc exhibit excellent stability with only ~ 9% decay in absorbance over 24 h even at high electrolyte concentration. Using KCl, KBr and NaCl electrolytes, the stability of the synthesized Ag Nps@suc also compares favorably to Ag Nps@cit.

Effect of Ag-doping on the structural, optical, electrical and photovoltaic properties of thermally evaporated Cadmium Selenide thin films

To study the capability of the CdSe thin films to use as an absorber layer in semi-transparent thin film solar cells, the structural, optical, electrical and photovoltaic properties of thermally evaporated CdSe thin films (thickness 300 nm) as a function of silver-doping were investigated. A novel and facile method was used to Ag-doping of the samples. Some aqueous solution of silver nitrate (with various concentration) was spin coated onto the surface of CdSe thin films followed by air-annealing to diffuse silver dopants into the layers. The field emission scanning electron microscope (FE-SEM) images showed that the surface of CdSe thin films was improved with our doping method. X-ray diffraction (XRD) analysis revealed the hexagonal structure of the samples. The crystallite size, micro-strain and dislocation density of CdSe thin films were evaluated using XRD patterns. The transmittance spectra in the wavelength range of 400–2500 nm were measured and then used to study other optical parameters. The optical energy band gap was decreased with Ag-doping from 1.96 eV to 1.67 eV. The electrical conductivity of FTO/CdSe:Ag/Al Schottky junction devices was improved by Ag-doping, and the photovoltaic efficiency was increased by Ag-doping form 1.53% for the undoped sample to 2.78% for the sample with the highest doping concentration. Obtained results show that Ag-doped CdSe thin films are a promising candidate to use as an absorber layer in semi-transparent solar cells and colorful photovoltaic windows.

Membrane Absorption of Ethylene from a Mixture with Ethane Using MDK-3 Composite Membranes

Separation of olefin/paraffin mixtures is an important problem. The use of a gas—liquid membrane contactor is an attractive alternative to traditional power-consuming cryogenic distillation methods. The paper deals with the separation of ethylene from its mixture with ethane (component ratio 19/81 vol %, respectively) using an aqueous silver nitrate solution as a selective ethylene absorbent in a flat-sheet lab-scale membrane module equipped with an MDK-3 commercial composite membrane with the selective layer based on silicone rubber. The effect of the absorbent and gas mixture feed linear velocities on the residual ethylene content of the mixture is considered. The thin selective layer of the membrane is shown to preserve high performance during long-term experimental run ensuring high mass-exchange characteristics and preventing the absorbent penetration into the porous structure of the membrane support.

Potential in-vitro anti-breast cancer activity of green-synthesized silver nanoparticles preparation against human MCF-7 cell-lines

An efficient bio-catalyzed synthesis of silver nanoparticles from aqueous silver nitrate solution was carried out utilizing the fresh Buchanania axillaris leaves’ aqueous-n-butanolic extract. The high-density yield silver nanoparticles were characterized by UV-Vis (Ultraviolet-visible), Fourier-transform infra-red (FT-IR), X-ray diffraction (XRD), energy dispersive-absorption X-rays (EDX), size and zeta potential analyses. The spherical morphology was confirmed by the scanning electron microscopy (SEM) of the purified product’s sample. The UV-Vis absorption λmax was observed at 419 nm while the IR absorption bands showed up at 3435, 2923, 2852, 1629, 1384, 1056, and 616 cm−1 for the capped nanosilver product. The particle sizes ranged approximately between 17–80 nm. The XRD and EDX spectroscopies confirmed the silver’s elemental composition. The biosynthesized silver nanoparticles showed significant cytotoxicity at a minimum dose of 10 μg ml−1, and an IC50 value of 31.2 μg ml−1 was established in the MTT assays when tested against human breast cancer cell-lines, MCF-7. The cytotoxicities were examined at different concentrations (10 to 100 μg ml−1) as compared to the controls, and the percent inhibitions of the cells’ growths were found increased with increasing concentrations of the silver nanoparticles. Also, the viability of the cells decreased with the increasing concentrations of the silver nanoparticles while the morphological examinations of the MCF-7 cancer cells showed distinguishable alterations in the morphology. Significant cell density changes were also observed confirming the anti-cancer action of the synthesized silver nanoparticles.

Liquid-Phase Synthesis of Silver Sulfide Nanoparticles in Supersaturated Aqueous Solutions

Silver sulfide powders and colloidal solutions were synthesized by chemical deposition from aqueous solutions of silver nitrate and sodium sulfide in the presence of sodium citrate as a stabilizing agent. X‑ray diffraction, electronic microscopy, the Brunauer–Emmett–Teller method, and dynamic light scattering were used to determine nanoparticle sizes in the deposited powders and colloidal solutions. The varying reagent concentrations in the reaction mixture provided nanopowders with average particle sizes ranging from ~1000 to ~40–50 nm. Silver sulfide nanoparticles in colloidal solutions have sizes of 15–20 nm. A qualitative correlation is found between the silver sulfide particle size and the supersaturation of the solutions used in the synthesis.

Phytochemical Synthesis of Silver Nanoparticles Using Anthemis Nobilis Extract and Its Antibacterial Activity

Abstract In this work, green synthesis of silver nanoparticles is described by phytochemical reducing silver nitrate aqueous solution using Anthemis nobilis. For this purpose, Anthemis nobilis extract was used for the synthesis of silver nanoparticles as both surfactant and reducing agent. Green synthesis method is a good alternative to physical and chemical methods, since it is fast, simple, environmentally-friendly and economic. The produced nanoparticles are identified using FE-SEM, EDX, and FT-IR and Uv/Vis techniques. Formation of silver nanoparticles is verified in 430–420 nm range. Reduction of silver ions by hydroxyl functional group is also confirmed by FT-IR device. EDX device confirms the presence of a peak for Ag element without any impurity peak. Silver nanoparticles are identified by FE-SEM device and found to have average size between 17 and 42 nm. Also, the antibacterial activity of the synthesized nanoparticles is compared with that of staphyloccusaureus and pseudomonasa aeruginosa and the maximum inhibitory activity against the bacteria is obtained using 1 mM nitrate solution.

Precipitation of Nanocrystalline Silver Sulfide from Aqueous Solutions Containing a Stabilizer

Chemical precipitation from aqueous solutions of silver nitrate and sodium sulfide in the presence of sodium citrate as a stabilizer was used to synthesize powders and colloidal solutions of silver sulfide Ag2S. The methods of X-ray diffraction, dynamic light scattering, and low-temperature adsorption of nitrogen were used to estimate sizes of silver sulfide particles in the precipitated powders and colloidal solutions. Changing the ratio between the reagent concentrations in reaction mixtures made it possible to obtain Ag2S nanopowders with average particle sizes within the range from ∼1000 to 40–50 nm. The size of Ag2S nanoparticles in the colloidal solutions obtained is 15–20 nm. The relationship between the particle size of silver sulfide and the supersaturation of solutions used for synthesis was considered.

Size Controlled Green Synthesis of Biocompatible Silver Nanoparticles with Enhanced Mosquito Larvicidal Activity

The present study focuses on rapid and green synthesis of silver nanoparticles (AgNPs) by using aqueous extract of Indian spice Asafoetida. To study the enhanced reducing and capping activity of Agave americana, four different combinations were employed, where a fixed volume of Asafoetida aqueous solution was mixed with different proportions of 1 mM aqueous silver nitrate solution and A. americana extract. Formation of AgNPs was signified through color change from colorless to dark brown and confirmed using UV–Vis spectral analysis. SEM and TEM results showed spherical and well dispersed AgNPs with particle size ranging between 50 and 125 nm, more over the X-ray diffraction patterns signified their crystalline nature. FTIR spectra of different combinations exhibited consistent pattern of decreasing particle size with increasing ratios of extracts which was also reflected in their larvicidal activity. The larvicidal application of these nanoparticles was also studied against three mosquito vectors and found most effective against malaria vector, Anopheles stephensi. Risk assessment was monitored on HEK 293 cell lines and proved safer with range of 92.8–78.2% cell viability after 24 h. This is first report where size of AgNPs was controlled through phytoextract combinations and additive effect was validated through enhanced larvicidal activity and biocompatibility.

Investigation of Microstructural and Optical Properties of Ag<sub>3</sub>O<sub>4</sub> Thin Films Sprayed onto Glass Substrate

In the present work we studied the effect of temperature and molarity on microstructural and optical properties of Ag3O4 thin films deposited by spray pyrolysis. Transparent conductive thin films of silver oxide (Ag3O4) were prepared by using an aqueous solution of silver nitrate (AgNO3) and sprayed onto heated soda glass substrate at 350 °C and annealed at 550°C. X-ray diffraction showed that the films have a monoclinic structure with a preferential orientation along the (031) direction. A visible shift of the main peak as a function of temperature and solution molarity is observed. The lattice parameters a, b and c are estimated to be 3.68, 9.30 and 5.20Ǻ respectively. Scanning Electron Microscopy (SEM) analysis shows that all films are nanostructured and homogeneous with dense surfaces. Transmittance and reflectance measurements are performed in the spectral range 200-1600 nm and yielded a band gap energy (Eg) varying in the range 3.07-3.25 eV. Refractive index was studied in terms of Moss, Ravindra and Herve–Vandamme models. The optical constants such as the oscillator energy (E0), static refractive index (n0), dispersion energy (Ed) and dielectric parameters (εr ) of the films were derived from the analysis and discussed.

Silver nanoparticles deposited on calcium hydrogenphosphate – silver phosphate matrix; biological activity of the composite

Abstract The composite containing nanosilver uniformly deposited on matrix composed of CaHPO4 x 2H2O (brushite, ca 89 mass %), CaHPO4 (monteonite, ca 9.5 mass%), and Ag3PO4 (0.5 mas%) was obtained by addition of calcium nitrate and silver nitrate aqueous solution at 30:1 Ca:Ag molar ratio into excess of (NH4)2PO4 solution at pH 5.0 – 5.5. The isolated solid was characterized by STEM, XRD, and LDI mass spectrometry. It has been found that nanosilver was uniformly distributed within composite as <10 nm diameter sized nanoparticles. Determination of silver by AAS showed that 60% of silver is present as Ag(0) nanoparticles, the present as matrix Ag3PO4 as identified by XRD method. The composite showed strong growth inhibition in E. coli and P. aeruginosa strains, and moderate towards S. aureus. The C. albicans cells were the most resistant to the tested material, although still composite was moderately cytostatic for the yeast.

The Thermal Expansion of AgxPb1 – xS Limited Semiconductor Solid Solutions

One-phase powders of AgxPb1 – xS cubic solid solutions with a maximum relative silver content to x = 0.12 were synthesized via the chemical codeposition from lead acetate and silver nitrate aqueous solutions in the presence of sulphidizer, as well as complexing and stabilizing agents. The thermal expansion of produced semiconductor solid solutions was first measured via the dilatometry in a temperature range of 295–580 K. As shown, substituting silver atoms for lead in AgxPb1 – xS results in a slight decrease in thermal expansion value, because of alterations in unharmonism of atomic vibrations.

Thermal Expansion of Nanostructured Solid Solutions of Lead and Silver Sulfides

Cubic solid solutions AgxPb[Formula: see text]S are synthesized by chemical co-deposition from aqueous solutions of lead acetate and silver nitrate in the presence of a sulfidizing, complexing and stabilizing agent. For the first time, thermal expansion of the synthesized semiconductor solid solutions AgxPb[Formula: see text]S is determined.

Structure Control for Preparing High-Ionic Conductive Hybrid Nanofiber

Silver iodide (AgI) shows extremely high ionic conductivity, especially in α-phase crystals produced only above 147 °C. To obtain high ionic conductivity of α-AgI crystals near room temperature, we prepared a hybrid nanofiber with nano-sized AgI particles. Initially, potassium iodide (KI) and polyamide 6 (PA6) complex nanofibers were prepared using an iodophor solution of PA6 and KI in formic acid by electrospinning, and immersed into an aqueous silver nitrate solution. Structure and properties of as-spun KI/PA6 complex nanofibers, and the resulting AgI/PA6 hybrid nanofibers, were characterized by scanning electron microscopy (SEM), wide-angle X-ray diffraction (WAXD), and electrical conductivity measurements. Spun complex nanofibers ranged from ∼30 to 300 nm in diameter.

Enhancement of Light Extraction Efficiency for InGaN/GaN Light-Emitting Diodes Using Silver Nanoparticle Embedded ZnO Thin Films.

In this study, we propose a liquid-phase-deposited silver nanoparticle embedded ZnO (LPD-Ag NP/ZnO) thin film at room temperature to improve the light extraction efficiency (LEE) for InGaN/GaN light-emitting diodes (LEDs). The treatment solution for the deposition of the LPD-Ag/NP ZnO thin film comprised a ZnO-powder-saturated HCl and a silver nitrate (AgNO3) aqueous solution. The enhanced LEE of an InGaN/GaN LED with the LPD-Ag NP/ZnO window layer can be attributed to the surface texture and localized surface plasmon (LSP) coupling effect. The surface texture of the LPD-Ag/NP ZnO window layer relies on the AgNO3 concentration, which decides the root-mean-square (RMS) roughness of the thin film. The LSP resonance or extinction wavelength also depends on the concentration of AgNO3, which determines the Ag NP size and content of Ag atoms in the LPD-Ag NP/ZnO thin film. The AgNO3 concentration for the optimal LEE of an InGaN/GaN LED with an LPD-Ag NP/ZnO window layer occurs at 0.05 M, which demonstrates an increased light output intensity that is approximately 1.52 times that of a conventional InGaN/GaN LED under a 20-mA driving current.

Synthesis of silver nanoparticles using aqueous extracts of Pterodon emarginatus leaves collected in the summer and winter seasons

The aim of the present study was to evaluate the potential of silver nanoparticle synthesis using extracts from the leaves of Pterodon emarginatus (white sucupira) collected during the summer and winter seasons. Leaves were collected for the production of aqueous extracts, which were added to the aqueous solutions of silver nitrate leading to a final concentration of 1 mM. The reactions were incubated at 75 °C for 150 min and monitored every 30 min by absorption spectroscopy at 425 nm. The samples were complementarily characterized by dynamic light scattering, zeta potential, transmission electron microscopy, atomic force microscopy, MALDI-TOF mass spectrometry, Fourier transform infrared spectroscopy and X-ray diffraction analyses. Both extracts (summer and winter) exhibited a satisfactory reduction of silver ions, capable of inducing the formation of AgNPPe with considerable colloidal stability. The seasons of leaf collection interfered with the synthesis and yield of the AgNPPe, and also with their hydrodynamic diameters and zeta potentials, but the particles showed similar dry sizes (height and diameter), molecular profiles, and crystallinity patterns of the atoms. In sum, the results indicated that some AgNPPe parameters can be tunable by seasonal aspects of the plants and, therefore, such nanomaterials are propitious aiming future evaluation of their applications in several areas.

Effect of ferrocene on the fabrication of honeycomb-patterned porous polystyrene films and silver functionalization of the film

Honeycomb-patterned (HCP) porous polystyrene (PS) film was fabricated by the breath figure method with inclusion of ferrocene in the PS solution for silver (Ag)-functionalization. Ag-functionalized HCP porous PS film was obtained by immersing the fabricated film in aqueous silver nitrate solution through interfacial reduction by ferrocene. The addition of ferrocene in the polymer solution also affected the morphology of the HCP porous film during the fabrication process. Depending on the used ferrocene concentration, morphology of the obtained Ag morphology on the film surface was different. By increasing the ferrocene concentration the reduced silver particles changed to silver nanowire without much aggregation and also increased the conductivity of the films. This method of silver-functionalization on the polymer film unleashes the futuristic applications in interdisciplinary fields such as substrates for Raman scattering and antibacterial studies.

Microwave Assisted Green Synthesis of Silver Nanoparticles Using Mulberry Leaves Extract and Silver Nitrate Solution

In this work, silver nanoparticles (AgNPs) were synthesized quickly and in an eco-friendly manner using the extract of Mulberry leaves and aqueous solution of silver nitrate without any toxic chemicals (Yuet et al. Int. J. Nanomed. 2012, 7, 4263–4267; Krishnakuma and Adavallan. Adv. Nat. Sci. Nanosci. Nanotechnol. 2014, 5, 025018). The Mulberry leaves extract functions as both a stabilizing and reducing agent. The UV-Vis spectroscopy shows a peak maximum at 430 nm. The transmission electron microscopy (TEM) image illustrated of synthesized AgNPs were nearly spherical-shaped particles whose sizes range from 15 to 20 nm. The TEM image of Nano Silver solution sample synthesized by the microwave assisted method shows nearly spherical particles, with an average particle size estimated at 10 nm. The absorption UV-vis spectrum of silver nanoparticles synthesized by the microwave assisted method (AgNPsmw) shows a sharp absorption band around 415 nm. The UV-Vis spectrum of AgNPsmw after two months of storage shows negligible peak changes of silver nanoparticles.

Facile in situ formation of high conductive Ag and CuxOy composite films: a role of aqueous spray combustion

In the present contribution, in situ formation of low-temperature high conductive composite films composed of pure silver and oxides of copper (CuxOy where, x = y = 1 for CuO and x = 2, y = 1 for Cu2O), are presented through spray combustion with a balanced stoichiometric redox reaction. High electrical conductivity (~ 7.8 × 105 S/cm) was retained in the composite film at an annealing temperature of 170 °C with matrix silver phase being 50% by volume. Whereas electrical conductivity of spray combustion processed pure silver is found to be ~ 2 × 106 S/cm. In situ formation of the composite film directly from the silver and cupric nitrate aqueous precursor solution through spray combustion proves it to be compositionally tunable with minimal usage of noble metal. Presence of Ag and CuxOy is confirmed by X-ray diffraction and X-ray photoelectron spectroscopy. The ratio of Cu1+/Cu2+ in the composite is found to be 0.54 and 0.43 at an annealing temperature of 170 °C and 400 °C respectively. The transformation of Cu2O to CuO is highly a thermally activated phenomenon; as the vacancy driven electrical conductivity is more in Cu2O than CuO, stabilization of Cu2O at a lower temperature is desired. The composite electrode can have potential applications in optoelectronics, printed electronics and catalysis.