Search

Highlights • LiFePO 4 are modified by rGO/Ag additives via a facile thermal reduction process. • The electrochemical properties of LiFePO 4 are dramatically improved by rGO/Ag. • LiFePO 4 @rGO/Ag exhibits the discharge specific capacity of 162 mAhg−1 at C/10. • LiFePO 4 @rGO/Ag exhibits the excellent cycling stability and rate capability. Abstract After synthesized with a solvothermal process, LiFePO 4 nanoparticles have been further modified with reduced graphene oxide (rGO) and Ag nanoparticles via a facile heat treatment route. The as-prepared LiFePO 4 @rGO/Ag exhibits enhanced electrochemical performance in storing Li ions with more than 60% increase in discharge specific capacity compared with pristine LiFePO 4 at C/10. The discharge specific capacity of the as-prepared cathode materials reaches to 130 mAhg−1 at high rate of 5 C, which is about 4 times higher than that of pristine LiFePO 4. The highly enhanced electrochemical properties of the cathode materials can be attributed to the synergetic effect of rGO nanosheets and Ag nanoparticles, which can build up conductive networks to form 3D nanocomposites together with LiFePO 4. [ABSTRACT FROM AUTHOR]

Poly(N-vinylpyrrolidone) (PVP) nanofiber mats were electrospun from a solution containing silver nitrate and 254 nm UV light was used to, simultaneously, photo-crosslink the polymer and promote silver nanoparticles (AgNP) formation. PVP cross-linking gives rise to a peak at 290 nm in the UV–Vis spectrum while the surface plasmon resonance of AgNP appeared at 420 nm. PVP-AgNP mats showed inhibitory effects on bacteria and fungi. This work shows that a PVP-AgNP wound dressing that ensures antimicrobial protection can be produced following a simple route. [ABSTRACT FROM AUTHOR]

• AgNPs was synthesized by R. offcinalis , U. dioica and V. vitis-idaea extracts. • Simple, environmentally friendly and economic method. • Extracts functional groups are key factor in formation and stability of AgNPs. In this work three different plant extracts (R. officinalis, U. dioica and V. vitis-idaea) were used for AgNPs bioreduction. IR spectroscopy, UV–vis, TEM and size distribution analyses were used for functional groups identification and AgNPs characterization. UV–vis spectrum of solution with R. officinalis extract showed strong, narrow peak at 418 nm (peak confirmed presence of AgNPs), also TEM analysis confirmed formation of fine (Ø10–20 nm), spherical AgNPs. Additionally, these nanoparticles were very stable. UV–vis spectrum of solution with U. dioica extract showed peak at 408 nm, NPs were uniform, spherical (∼15 nm) but they stability was not constant (after few days agglomeration started). Nanoparticles synthesized by V. vitis-idaea extract were extremely unstable, agglomeration appeared immediately after extract adding. IR spectra confirmed differences in composition of R. officinalis, U. dioica and V. vitis-idaea extracts. [ABSTRACT FROM AUTHOR]

We presented the employment of ascorbic acid as the reducing agent for the in situ deposition of Ag nanoparticles on the surface of TiO 2 nanotube arrays (TiO 2 NTs/Ag). The structural investigation by scanning electron microscopy and transmission electron microscopy indicated that Ag nanoparticles with average diameters of 15 nm uniformly grew on TiO 2 NTs walls. The possible formation mechanism of TiO 2 NTs/Ag was proposed. UV–vis absorption and photoelectrochemical measurements indicated that the Ag sensitization extended the visible light absorption region, improved the photocurrent response, and enhanced solar-induced photoelectrocatalytic activities. [ABSTRACT FROM AUTHOR]

[Display omitted] • Silver nanoparticles (AgNPs) were biosynthesized using Opuntia joconostle fruit. • No infusion was required for the formation of AgNPs with mean diameter of 17.7 nm. • AgNPs detect colorimetrically and selectively Hg2+ ion in aqueous solution. • Functionalization of AgNPs is not required for sensing Hg2+ ion even in tap water. Silver nanoparticles (AgNPs) have been synthesized, for the first time, using the pulp of Opuntia joconostle fruit as reducing reagent of Ag+ ions. The reported method is wholly green, since no temperature or infusion preparation were required. AgNPs with a 428 nm plasmon absorbance, a quasi-spherical morphology, a mean size of 17.7 nm, and an FCC crystal structure were obtained. These biogenic AgNPs, without further chemical functionalization, could sense easily (naked eye) and selectively the presence of Hg2+ ions in aqueous solution and in tap water. [ABSTRACT FROM AUTHOR]

• Flower-ball shaped Ag/Bi 2 WO 6 material was synthesized by hydrothermal method. • The gas sensing performance of Ag/Bi 2 WO 6 for ethanol was investigated for the first time. • Ag/Bi 2 WO 6 -based gas sensor has a fast response speed of up to 7 s for ethanol. • The sensor based on Ag/Bi 2 WO 6 showed low operating temperature of 240℃ to ethanol. Although Bi 2 WO 6 has been applied in various field, there are few reports on the application of gas sensing. In this work, Ag loaded flower-ball shaped Bi 2 WO 6 composite nanomaterials were synthesised by hydrothermal method. The Ag content was optimized for the first time. It was found that when 2 % Ag was added, Ag/Bi 2 WO 6 material possessed high sensitivity and low optimal working temperature (240℃). Compared with pure Bi 2 WO 6 (11 s and 32 s), Ag/Bi 2 WO 6 possessed ultrashort response and recovery time of 7 s and 25 s. It exhibited better ethanol gas selectivity and stability. Unique crystal structure and Ag catalysis may lead to the improvement of gas sensing performance. [ABSTRACT FROM AUTHOR]

In the present work, special hierarchical structured Fe 3 O 4 nanoparticles (Fe 3 O 4 NPs)/Ag nanoparticles (AgNPs) dual-coated silk fibers have been prepared via a simple electrostatic self-assembly technology. Silk fibers were sequentially immersed in solutions of positively charged AgNPs and negatively charged Fe 3 O 4 NPs. As-prepared hierarchical structured silk fibers were characterized by XRD, FESEM, and VSM. XRD and SEM characterizations demonstrated that silk fibers were hierarchically and uniformly coated by high dense AgNPs and Fe 3 O 4 NPs. VSM analysis indicated that the as-prepared ternary composite fibers showed excellent magnetic property. [ABSTRACT FROM AUTHOR]

We report our successful fabrication of graphene quantum dots shell-isolated Ag nanoparticles (Ag@GQDs NPs) which size was in the range of 40–80 nm. To the best of our knowledge, this is the first report to fabricate Ag@GQDs NPs of less than 100 nm in particle sizes, particularly with monodispersion characteristic and smooth surface. Transmission electron microscopy (TEM) images reveal that Ag NPs cores are completely encapsulated by 2–4 layers of GQDs. More importantly, Ag@GQDs NPs show a significantly higher Raman signal for the absorbed crystal violet molecules as compared to Ag NPs, suggesting that the Ag@GQDs NPs can act as a new type substrate for surface enhancement of Raman scattering (SERS) substrate. [ABSTRACT FROM AUTHOR]

Ag-coated ZnO nanoparticles are synthesized by a biological process using Tribulus terrestris leaf extract. The characterization results confirmed that Ag nanoparticles have been coated on the surface of ZnO nanoparticles. Ag nanoparticles on the surface of ZnO are spherical in shape, ranging between 6 and 10 nm in diameter. Gas-sensing tests reveal that all the resistance values of the sensors decrease with increasing of eathanol concentration. Moreover, the resistance of Ag-coated ZnO sensor was generally much lower than that of pure ZnO sensor. Thus, Ag nanoparticles coating paly an important role for the sensitivity of the gas sensor working at room temperature. [ABSTRACT FROM AUTHOR]

Bacterial infection has been identified as one of the major causes of titanium implant failures. In this study, a novel antibiotic vehicle composite, TiO 2 NT–PSPMA, was synthesized via atom transfer radical polymerization; this method improved the local antibiotic concentration and prolonged its sustainable release by loading larger amounts of antibiotic into titania nanotubes (TiO 2 NTs) arrayed on Ti implants. Ag nanoparticles (NPs) were loaded into TiO 2 NTs with the assistance of the ionic polymer 3-sulfopropyl methacrylate potassium salt (PSPMA). This composite increased the storage of Ag NPs by employing nanotubes and using PSPMA to trap larger amounts Ag NPs. The in vitro experiments showed that the composite had a dose-dependent cell proliferation by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), indicating that the composite has the potential to prevent the devastating consequences of implant infection. [ABSTRACT FROM AUTHOR]

Ag-loaded GaN microrods arrays were synthesized by chemical vapor deposition. The products were characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy and spectrofluorometry. The results show that Ag-loaded microrods with rough surface had a diameter of about 1.5 μm. The obtained Ag-loaded GaN microrods were composed by face-centered-cubic metallic Ag and hexagonal wurtzite GaN. Comparisons of Ag-loaded GaN microrod arrays with pure sheet-like GaN displayed that the Ag-loaded GaN microrod arrays exhibited higher photocatalytic activity. The possible mechanisms of high photocatalytic activity should be ascribed to the added Ag nanoparticles act as a sink for photo-generated electrons. [ABSTRACT FROM AUTHOR]

Abstract: Ag nanoparticles (AgNP) with an average size of 12nm are successfully decorated on the reduced graphene oxide (rGO) sheets through a simple one-pot hydrothermal method using gallic acid as the reducing agent. This AgNP/rGO hybrid has been successfully applied in the catalytic performance toward the reduction of H2O2. The nonenzymatic sensor demonstrates a linear relationship in a wide concentration range of 0.05–5mM (R=0.999), and a high sensitivity of 255μAcm−2 mM−1 to the detection of H2O2. [Copyright &y& Elsevier]

Abstract: Ag nanoparticles were immobilized on echinoid-like TiO2 particles via an alcohol reduction process with poly(vinyl pyrrolidone) (PVP) of different molecular weights (Mw.). The sizes of Ag nanoparticles prepared by using PVP K15 (Mw.: 10,000) and K30 (Mw.: 40,000) were 12–15nm and 19–31nm, respectively. On the other hand, Ag nanoparticles were not observed when PVP K12 (Mw.: 3500) was used. The crystal structure of Ag nanoparticles formed on TiO2 was face-centered cubic silver phase and the chemical states of Ag nanoparticles were Ag+ and Ag0. The photocatalytic performance was enhanced by Ag deposition. Among the samples, the prepared Ag/TiO2 composite by using PVP K15 exhibited better photocatalytic activity than other composites due to its higher Ag coverage on the TiO2 surface. [Copyright &y& Elsevier]

Abstract: The incorporation of Ag nanoparticles on mesoporous silica as the supporting material and their catalysis for oleic acid hydrogenation were described in this study. The template removal and Ag nanoparticle incorporation were concurrently taken place in the novel glow discharge in a solution, namely solution plasma process under controlled conditions. With only 15min of discharge time, Ag nanoparticles were incorporated on the mesoporous silica matrix confirmed by the evidences of XRD and TEM and the template inside mesopores was mostly removed confirmed by FTIR spectra. The hydrogenation catalysis of oleic acid was preliminarily tested using UV–VIS spectroscopy after oxidation using permanganate ions (MnO4 −). It was found that the conversion was observed to be 12.83% in the butanol system and reached to 90.56% in ethanol. [Copyright &y& Elsevier]

Abstract: Monodisperse carbon hollow spheres encapsulating silver nanoparticles have been successfully synthesized by a facile approach with imidazolium ionic liquid ([C14mim]BF4) as the soft template. Meanwhile, a novel Ag/C nanocomposite with an interesting structure, in which the carbon hollow spheres encapsulating silver nanoparticles were assembled by fine carbon wires, exists in this experiment. The Ag/C nanocomposites was characterized by XRD, TEM (HRTEM), SEM, FTIR spectroscopy, Raman spectrometer and energy dispersive X-ray analysis (EDX). The possible formation mechanism of the nanocomposites has been proposed. [Copyright &y& Elsevier]

Abstract: The effect of Ag nanoparticles on the luminescent properties of the europium complex, where the complex is ethylenediamine tetra acetate (EDTA), was investigated in the aqueous solution system. We observed the formation of nanoparticle aggregates and the appearance of a new absorption and enhancement of the emission intensity for the complex solution containing Ag nanoparticles when the pH of the complex solution is 3–4.6. Furthermore, with increasing Ag nanoparticles concentration enhancement efficiency first increases and then decreases. The enhancement effect was discussed in terms of the effects of nanoparticle aggregates, the local electromagnetic field enhancement effect and optical absorption due to surface plasmon resonance. [Copyright &y& Elsevier]

Abstract: Herein, we report on the preparation and characterization of polyimide (PI) membranes containing Ag nanoparticles in pores distributing on one side. The presence of the Ag nanoparticles in the pores was confirmed by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Plasma Emission Spectrometer. The results showed that the pores distributed on bottom side of the membranes, and the Ag nanoparticles dispersed evenly on the wall of the pores. The pores provided excellent dispersing environment for the Ag nanoparticles. The quantities and dispersing densities of Ag nanoparticles are larger when they are prepared from silver nitrate (AgNO3) solutions with higher concentration. [Copyright &y& Elsevier]

Abstract: A simple one-step method of preparing of ultrafine poly(acrylonitrile) (PAN) fibers containing Ag nanoparticles was developed. Ag+ ions in a PAN solution were directly reduced to produce Ag nanoparticles and the resulting solution was electrospun into ultrafine PAN fibers. N,N-dimethylformamide (DMF) was used as a solvent for PAN as well as a reducing agent for the Ag+ ions. The numbers of Ag nanoparticles in the ultrafine PAN fibers were increased as the amount of AgNO3 was increased from 0.05 to 0.5 wt.%. The Ag nanoparticles were all sphere shaped with an average diameter of less than 5.8 nm. [Copyright &y& Elsevier]

Abstract: Dispersions of Ag, Pd, and Pt–Ru alloy nanoparticles in poly(vinylpyrrodione) (PVP) were produced by γ-irradiation induced reduction of metal ions at room temperature. The photographs from Atomic Force Microscopy (AFM) inform that Ag, Pd, and Pt–Ru alloy nanoparticles were dispersed with the particle sizes of about 25 nm, 0.6–1.5 nm, and 15 nm, respectively, in the aqueous dispersions. The nanoparticles of metals (Ag, Pd,) and alloy (Pt–Ru) were also dispersed on single-walled carbon nanotubes (SWCNTs) as supporting materials using γ-irradiation at room temperature. Of interest, the attachment of the nanoparticles onto SWCNTs was strong enough to be present even after chemical cleaning and ultra-sonication. FT-IR spectroscopy gives evidence for the surface modification of SWCNTs through the presence of characteristic peaks of carboxyl and hydroxyl groups and provides support for the dispersion of nanoparticles on the surface of SWCNTs. [Copyright &y& Elsevier]

• A novel Ag paste containing MOD is proposed for assisting nanoparticle sintering. • The sintering assistance mechanism of MOD was studied. • A maximum joint strength of over 40 MPa was achieved. In this paper, we have developed a novel Ag paste containing MOD (metal organic decomposition) for assisting the sintering of nanoparticles. Based on the prepared Ag paste, the bonding joint can reach a maximum shear strength of 42.7 MPa at 175 °C. The effect of different amines on the performance of bonded joints was studied to elucidate the mechanism of MOD assisted sintering. Due to the advantage of high sintering performance, the new MOD assisted Ag paste is promising to be applied in the field of WBG device packaging. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) nanomaterials, such as boron nitride (BN), molybdenum disulfide (MoS 2 ), have attracted increasing research interest in the past few years because of the unique properties of graphene. The monolayer and few-layers MoS 2 nanosheets were obtained by combined low-energy ball milling and sonication. A self-assembly method was then applied to load silver nanoparticles (AgNPs) onto the two-dimensional MoS 2 nanosheets for the fabrication of 0D/2D multifunctional nanocomposites with an enhanced Raman affect. The AgNPs are uniformly dispersed on the MoS 2 nanosheets and the particle size of the AgNPs is about 4 nm. The AgNPs/MoS 2 nanocomposites are characterized by cyclic voltammetry, showing excellent electrochemical performances. [ABSTRACT FROM AUTHOR]

• A conductive nanofiber composite is successfully fabricated by in situ reduction Ag NPs. • The conductive TPU nanofiber composite demonstrates good stability in harsh conditions. • The nanofiber composite sensor possesses a high sensitivity and broad working range. • The sensor was able to detect full range detection of human body motions. Flexible strain sensors have received wide attention due to their potential applications in wearable devices. However, the development of strain sensors with higher stretchability, and larger workable strain range still remains a challenge. Here, a conductive nanofiber composite with a hierarchical silver nanoparticles (Ag NPs) shell and thermoplastic polyurethane (TPU) nanofiber core microstructure are constructed via depositing Ag NPs on TPU nanofiber mats surface with the aid of tannic acid (TA) and hydrolysable 3-aminopropyltriethoxysilane (APTES) hybrid coating (TA-APTES coating). The prepared strain sensor demonstrates high stretchability with maximum strain of 565% and high sensitivity with a gauge factor (GF) of about 6886. In addition, the TPU@(TA-APTES)@Ag NPs composite strain sensor can be applied to detect human motions. [ABSTRACT FROM AUTHOR]

• The high-temperature stability of sintered Ag joints was enhanced by local TLP. • Joints was formed by sintered Ag, Ag-Sn IMC and Cu-Sn IMC. • The Ag-Sn IMCs has excellent anti-coarsening property. • The Cu-Sn IMC barrier hindered the diffusion of Cu atoms from substrate. • The shear strength maintained above 60 MPa after ageing at 300 ℃ for 1000 h. We proposed a new approach to improve the thermal stability of sintered Ag joints on bare Cu substrates. In the sintering process, Ag-Sn intermetallic compounds (IMCs) formed at the edges of sintered joints that could inhibit the penetration of oxygen and the microstructural coarsening behaviour of sintered Ag. Cu-Sn and Ag-Sn IMCs formed at the bottom of the joints simultaneously. This IMC barrier hindered the diffusion of Cu atoms towards the sintered Ag layer and the formation of Cu oxides effectively. A high-temperature (300 ℃) storage test in air demonstrated that the shear strength of this kind of joint maintained above 60 MPa for 1000 h. [ABSTRACT FROM AUTHOR]

Abstract: Silver nanoparticles have been successfully synthesized by the sonochemical route using sodium borohydride and sodium citrate as the reducing agents. The effect of the reducing agents on the particle size and morphology has been studied by carrying out the two reactions at the same ultrasound frequency (20KHz). The strong reducing agent (NaBH4) produced spherical silver nanoparticles of sizes 10nm whereas sodium citrate led to much smaller silver nanoparticles of ~3nm diameter. Powder X-ray diffraction studies reveal a high degree of crystallinity and monophasic silver particles. UV–Visible studies show the presence of a surface plasmon band at 405nm. However the reflectance spectra give a broad band between 340 and 360nm which is characteristic for the quasi-spherical silver nanoparticles. The specific surface area was found to be 2.6 and 13.1m2/g and the pore radius was found to be 15.2 and 12.3Å for silver nanoparticles obtained by the sodium borohydride and sodium citrate reduction respectively. [ABSTRACT FROM AUTHOR]

Abstract: Herein we report on the production of composite core–shell particles, which are actually self-assembly of poly (N-isopropylacrylamide)-based amphiphilic block copolymers as a template for metal-block copolymer nanocomposites formation. Organic–inorganic composites were prepared with Ag nanoparticles embedded within colloidal particles of an amphiphilic, thermally responsive polymer. To promote the incorporation of unaggregated Ag nanoparticles, temperature responsive microspheres of poly (N-isopropylacrylamide) (NIPAM) block with polystyrene were synthesized. Polyethyleneimine (PEI) could act as the linker between Ag ions (Ag nanoparticles) and poly (styrene-b-N-isopropylacrylamide) (PS-b-PNIPAM) colloids and the reducing agent in the formation of Ag nanoparticles. Transmission electron microscopy (TEM) measurements confirmed the nanostructures, 1HNMR and FTIR characterized the components of the resulting nanoobjects. These stimuli-responsive hybrid microspheres will have potential applications in biomedical areas, such as tissue engineering and drug delivery. [Copyright &y& Elsevier]

Abstract: Silver nanoparticles were precipitated directly in Ag+ doped silicate glass by a 150 fs, 800 nm, 250 kHz femtosecond laser irradiation. The irradiated pattern turned to yellow without heat treatment. The absorption peak about 400 nm, ascribed to the surface plasmon resonance of the formed silver nanoparticles, was observed. We believe that the reduced Ag atoms, via capturing free electrons created by multi-photon process, may aggregate into the Ag nanoparticles due to femtosecond laser inducing heat accumulation effect. This result has promising applications for the fabrication of 3D multi-colored images inside a transparent material. [Copyright &y& Elsevier]

• Ag NP-anchored N-enriched carbon synthesized from melamine-oxalic acid complex. • The catalyst was efficient towards reduction of 2-CH 3 - p -nitrophenol using NaBH 4. • Reduction of 2-CH 3 - p -nitrophenol followed six electron transfer mechanism. • The catalyst retained its activity even after eight test runs. A facile technique for preparing the stable Ag nanoparticles (NPs) of 5–19 nm average size, anchored onto the heat-treated melamine-oxalic acid supramolecular complex is demonstrated. The synthesized material is tested for its catalytic efficiency towards reduction of aqueous 2-CH 3 - p -nitrophenol to aminophenol using NaBH 4 as reducing agent at 28 °C. The reaction followed the pseudo first-order kinetics with respect to the nitrophenol concentrations, and the reaction rate constant was determined to be greater than the reported literature values. The superior catalytic activity of the catalyst was attributed to the combined roles of the Ag NPs and carbon substrate enriched with nitrogen functional groups. Notably, the prepared catalyst sustained its reactivity even after eight consecutive test runs without leaching of the metal NPs in the reaction mixture. The results clearly indicate the organic complex precursor-based carbon supported Ag NPs to be an efficient catalyst for removal of recalcitrant organic compounds from wastewater by reduction. [ABSTRACT FROM AUTHOR]