An efficientfficient,controllable and facile two-step synthesis strategy: Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>@RGO composites with various Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> nanoparticles and their supercapacitance properties

An efficient,controllable,and facile two-step synthetic strategy to prepare graphene-based nanocomposites is proposed.A series of Fe3O4-decorated reduced graphene oxide (Fe3O4@RGO) nanocomposites incorporating Fe3O4 nanocrystals of various sizes were prepared by an ethanothermal method using graphene oxide (GO) and monodisperse Fe3O4 nanocrystals with diameters ranging from 4 to 10 nm.The morphologies and microstructures of the as-prepared composites were characterized by X-ray diffraction,Raman spectroscopy,nitrogen adsorption measurements,and transmission electron microscopy.The results show that GO can be reduced to graphene during the ethanothermal process,and that the Fe3O4 nanocrystals are well dispersed on the graphene sheets generated in the process.The analysis of the electrochemical properties of the Fe3O4@RGO materials shows that nanocomposites prepared with Fe3O4 nanocrystals of different sizes exhibit different electrochemical performances.Among all samples,Fe3O4@RGO prepared with Fe3O4 nanocrystals of 6 nm diameter possessed the highest specific capacitance of 481 F/g at 1 A/g,highlighting the excellent capability of this material.This work illustrates a promising route to develop graphene-based nanocomposite materials with a wide range of potential applications.     

Tailoring of optical and electrical properties of PMMA by incorporation of Ag nanoparticles

Silver–poly(methyl methacrylate) (Ag–PMMA) nanocomposite films were prepared via ex situ chemical route by employing sodium borohydride (\(\hbox {NaBH}_{4}\)) as a reducing agent. In this study, PVP-stabilized Ag nanoparticles were prepared and mixed with PMMA solution. Optical and structural characterizations of resulting nanocomposite films were performed using UV–visible spectroscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Characteristic surface plasmon resonance (SPR) peak of Ag nanoparticles was observed at about 3.04 eV (408 nm) in absorption spectra of Ag–PMMA nanocomposite films. TEM micrograph revealed that the spherical Ag nanoparticles with an average diameter of 5.4\(\,\pm \,\)2.5 nm are embedded in PMMA. In Raman spectra, besides shifting of vibrational bands, enhancement in intensity of Raman signal with incorporation of Ag nanoparticles was observed. Current (I)–voltage (V) measurements revealed that conductivity of PMMA increased with increasing concentration of Ag nanoparticles. Analysis of I–V data further disclosed that at voltage <2 V, ohmic conduction mechanism is the dominant mechanism, while at voltage >2 V Poole–Frenkel is the dominant conduction mechanism. Urbach’s energy, the measure of disorder, increased from 0.40 eV for PMMA to 1.11 eV for Ag–PMMA nanocomposite films containing 0.039 wt% of Ag nanoparticles.     

Organic/inorganic nanocomposite films based on poly(3-methoxythiophene) and WO3

Organic/inorganic nanocomposite films based on poly(3-methoxythiophene) (PMOT) and WO₃ were prepared by a consecutive two-step electrochemical method. The products were characterized in detail by scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDS) and Fourier-transform infrared spectroscopies (FTIR). The results show that the PMOT/WO₃ nanocomposite films consist of two layers, the substrate WO₃ with 30 nm grains and superstratum PMOT, which average grain size is 60 nm. The obtained PMOT/WO₃ nanocomposite films were also characterized by cyclic voltammetry to investigate their electrochemistry properties which display significant enhancement of electrochemical activity than that of pure PMOT and WO₃ films.     

超声辐照条件下HCl掺杂聚苯胺纳米棒的结构和性能

在超声辐照条件下,以HCl为掺杂剂、(NH4)2S2O8为氧化剂,通过溶液聚合得到了HCl掺杂聚苯胺(PA-NI)纳米棒.采用傅里叶变换红外光谱(FTIR)、透射电子显微镜(TEM)、X-射线衍射(XRD)、四电极电导率仪、热重分析(TGA)和电化学工作站对材料的结构与性能进行研究.研究结果表明,超声辐照条件下HCl掺杂PANI具有较高的掺杂程度和结构规整度,形成直径为50～65 nm左右的纳米棒状结构.与传统方法相比,超声辐照法所得材料的热稳定性在270～500℃有明显上升,室温电导率升至0.25 s/cm,并具有较好的电容行为和较高的电化学活性.     

Preparation of silver nanoparticles dispersed in polyacrylonitrile nanofiber film spun by electrospinning

Ag nanoparticles dispersed in polyacrylonitrile (PAN) nanofiber film spun by electrospinning were in situ prepared by reduction of silver ions in N₂H₅OH aqueous solution. The Ag/PAN nanocomposite film was characterized by UV absorption spectroscopy, transmission electron microscopy (TEM) and surface-enhanced Raman scattering (SERS) spectroscopy. UV spectrum and TEM image show that silver nanoparticles with average diameter of 10 nm were obtained and dispersed homogeneously in PAN nanofibers. SERS spectrum indicates that the structure of PAN has been changed after Ag nanoparticles are dispersed in PAN.     

Preparation and characterization of Chitosan/Konjac glucomannan/CdS nanocomposite film with low infrared emissivity

Novel organic-inorganic nanocomposite films were prepared with Chitosan (CS), Konjac glucomannan (KGM) and CdS by one-step synthesis. As-prepared films were characterized by IR spectra, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and infrared emissometer (IR). The results indicated that grown CdS dendrites were formed with reaction time of 12 h for Cd²⁺ and CS/KGM, and were well dispersed in CS/KGM with an average diameter of 40 nm. The CS/KGM/CdS nanocomposite films had significantly low infrared emissivity. When the mole ratio of CdS to summation of CS&KGM construction units was 1.0 with CdS size of 10-20 nm, the film got the lowest infrared emissivity value of 0.011, which could be attributed to the strong synergism effect existing between CS/KGM and CdS dendrites.     

Synthesis and nonlinear optical properties of nanometer-size silver-coated polydiacetylene composite vesicles

Two kinds of nanometer-size silver-coated polydiacetylene (PDA) composite vesicles were prepared by simple and effective approaches. Silver nanoparticles were coated onto the outer and inner surface (I) or only on the outer surface of PDA vesicles (II), respectively. UV-vis spectra and transmission electron microscopy (TEM) were used to confirm the formation of PDA/Ag nanocomposite vesicles. Nonlinear optical (NLO) properties of these PDA/Ag nanocomposite vesicles had been measured by the Z-scan technique. The value of n(2) for pure PDA vesicles was 1.2 × 10(-14)?cm(2)?W(-1). However, for PDA/Ag nanocomposite vesicles (on the outer surface) it was 7.3 × 10(-14)?cm(2)?W(-1). Nearly seven times enhancement was observed as a result of local field enhancement under the surface plasmon resonance of silver nanoparticles at the interface. NLO?properties of these PDA/Ag nanocomposite vesicles can be modulated by varying the size, shape and coverage of Ag nanoparticles and these PDA/Ag nanocomposite vesicles are expected to be good candidates for new optical and nonlinear devices.     

聚苯胺/聚四氟乙烯导电复合膜的电化学制备和表征分析

在聚四氟乙烯(PTFE)微孔膜上电化学制备硫酸和磺基水杨酸(SSA)共掺杂的导电聚苯胺(PANI)复合膜,采用四因素三水平的正交设计法优化工艺条件,并在其上继续沉积银,研究了沉积银电流密度和时间及拉伸对复合膜电导率的影响。采用拉曼光谱、X射线衍射和扫描电镜对复合膜进行了表征。结果表明,在最佳工艺条件下制备的PTFE-PANI复合膜电导率可达36.9S/cm,此复合膜经20mA/cm2沉积4min的银可使其电导率显著提高到5379S/cm。对最优条件制备的PANI-PTFE和PANI-PTFE-Ag复合膜进行适当程度的拉伸均可提高其电导率,PT-FE系列复合膜展现出较优异的力学性能。拉曼光谱表明PTFE、PANI和银复合良好。复合膜有一定的结晶度,经拉伸后复合膜结晶度增大,电导率显著提高;PANI在PTFE上呈颗粒状生长,颗粒尺寸均匀,直径约为200nm,Ag呈树枝状镶嵌、覆盖在PANI颗粒间,与PANI复合很好并形成三维导电网络。     

Microstructure,electrical and humidity sensing properties of TiO<Subscript>2</Subscript>/polyaniline nanocomposite films prepared by sol–gel spin coating technique

High sensitive resistive type humidity sensor based titanium oxide/polyaniline (TiO₂/PANI) nanocomposite thin films prepared by a sol–gel spin coating technique on an alumina substrate. The resultant nanocomposites were characterized by using X-ray diffraction (XRD), Field emission electron microscopy, Fourier transform infrared spectroscopy (FTIR), UV–Vis absorbance and energy dispersive spectra analysis. In the XRD patterns of both pure and TiO₂/PANI composite confirms the deposition of PANI on TiO₂ and the average size of the composite particle was found to be 32 nm. Large number of nano grain surface being covered by PANI, which agrees very well with the results obtained by XRD studies. FTIR and UV–Vis spectra reveal that the PANI component undergoes an electronic structure modification as a result of the TiO₂ and PANI interaction. The room temperature resistivity was found to be for TiO₂ and TiO₂/PANI nanocomposite films 1.42?×?10⁶ and 2.56?×?10³ Ω cm respectively. The obtained TiO₂/PANI nanocomposites sensor exhibited higher humidity sensing performance such as high sensitivity, fast response (20 s) and recovery time (15 s) and high stability.     

MWCNTs/Cu(OH)2 nanoparticles/IL nanocomposite modified glassy carbon electrode as a voltammetric sensor for determination of the non-steroidal anti-inflammatory drug diclofenac

This paper describes the development and utilization of a new nanocomposite consisting of Cu(OH)₂ nanoparticles, hydrophobic ionic liquid 1-ethyl-3-methylimidazolium hexafluorophosphate (EMIMPF₆) and multiwalled carbon nanotubes for glassy carbon electrode modification. The nanocomposite was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM) along with energy-dispersive X-ray spectroscopy (EDX). The modified electrode was used for electrochemical characterization of diclofenac. Using differential pulse voltammetry, the prepared sensor showed good sensitivity and selectivity with low overpotential for the determination of diclofenac in the range from 0.18 to 119 μM, with a detection limit of 0.04 μM. Electrochemical studies suggested that the MWCNTs/Cu(OH)₂ nanoparticles/IL nanocomposite modified electrode provided a synergistic augmentation on the voltammetric behavior of electrochemical oxidation of diclofenac, which was indicated by the improvement of anodic peak current.     

聚苯胺/银复合薄膜的制备及其耐蚀性能

为了研究聚苯胺(PANI)/银复合薄膜对不锈钢的防腐蚀性能,采用循环伏安法在不锈钢表面沉积一层Ag后,再通过对苯胺的电化学聚合制备了PANI膜。利用阳极极化法和交流阻抗法研究了PANI/Ag复合膜的耐蚀性及其影响因素。结果表明:在0.1 mol/L NaC l溶液中,不锈钢覆盖复合膜后的自腐蚀电位比无膜时有所提高,其耐蚀性能得到增强;电化学聚合溶液浓度、扫描速率及扫描上限等因素对复合膜耐蚀性的影响情况为:电解液中苯胺和硫酸浓度过高或过低都会影响膜的致密度,从而影响复合膜的耐蚀性;电化学参数的变化会影响复合膜的聚合速率,使复合膜的抗腐蚀能力不同;当苯胺单体浓度为0.2 mol/L、硫酸浓度为1 mol/L、扫描电位上限为1 V、扫描次数为50次、扫描速率为50 mV/s时,采用循环伏安法聚合苯胺,可形成沉积致密度高、耐蚀性好的复合膜。     

Green synthesis of the Ag/ZnO nanocomposite using Valeriana officinalis L. root extract: application as a reusable catalyst for the reduction of organic dyes in a very short time

A facile and green synthesis of the Ag/ZnO nanocomposite by extract of Valeriana officinalis L. root in the absence of any stabiliser or surfactant has been reported in this work. The green synthesised Ag/ZnO nanocomposite was characterised by Field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy dispersive X‐ray spectroscopy (EDS), elemental mapping, Fourier‐Transform infrared (FT‐IR), X‐ray diffraction analysis (XRD) and UV‐Vis spectroscopy. According to SEM and TEM images, the Ag and ZnO particles are spherical with diameters of less than 20 and 40–50 nm, respectively. The Ag NPs/ZnO nanocomposite proved to be an effective catalyst in the reduction of various dyes including methyl orange (MO), Congo red (CR) and methylene blue (MB) in the presence of NaBH₄ in aqueous media at ambient temperature. A maximum degradation (100%) of dyes was performed using Ag/ZnO nanocomposite. The extraordinary performance of the prepared Ag/ZnO nanocomposite is attributed to the synergetic effect induced by both ZnO and Ag NPs in the catalytic degradation of organic dyes. The catalyst could be reused and recovered several times with no significant loss of catalytic activity.Inspec keywords: nanocomposites, silver, zinc compounds, II‐VI semiconductors, nanofabrication, catalysts, reduction (chemical), field emission electron microscopy, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectra, ultraviolet spectra, visible spectra, X‐ray diffraction, surface morphology, nanoparticles, dyesOther keywords: green synthesis, nanocomposite, Valeriana officinalis L. root extract, reusable catalyst, reduction, organic dyes, surfactant, field emission scanning electron microscopy, transmission electron microscopy, energy dispersive X‐ray spectroscopy, elemental mapping, Fourier‐transform infrared spectroscopy, X‐ray diffraction analysis, surface morphology, nanoparticles, methyl orange, congo red, methylene blue, UV–Vis spectroscopy, size 40 nm to 50 nm, wavelength 493 nm, wavelength 465 nm, wavelength 663 nm, Ag‐ZnO     

水热微乳液法制备锂离子阳极材料CoS2纳米空心球

通过自制的纳米苯丙乳液粒子为吸附载体,以CoCl·6H2O和CS2为原料,在100℃水热条件下,于微乳液粒子表面反应6h制备出了CoS2空心纳米球.利用X射线粉末衍射仪(XRD)、透射电子显微镜(TEM)和扫描电子显微镜(SEM)对产物进行了表征.结果表明,所得产物为纯相的立方晶系CoS2空心纳米球,直径约120nm....     

Synthesis and characterization of an electro-deposited polyaniline-bismuth telluride nanocomposite — A novel thermoelectric material

The present work consists of synthesis and characterization of a novel thermoelectric material polyaniline (PANI)-bismuth telluride (Bi₂Te₃) nanocomposite using simultaneous electrochemical reactions and deposition method. The inorganic bismuth nitrate has been used as a dopant for polyaniline to achieve high electrical conductivity. A semi-batch mode of operation has been employed to control the rate of deposition of an individual component and thus the molecular architecture of the composite. The electro-deposited composite film on ITO coated glass substrate has been characterized by X-ray diffraction analysis (XRD), FTIR analysis, scanning electron microscope (SEM), and transmission electron microscope (TEM). The microscopic analysis reveals the formation of rod-like nanostructures of diameter less than 100 nm. It has been found that smaller molecules of Bi₂Te₃ are dispersed in the macromolecules of PANI. The nanocomposite has been characterized by thermoelectric power.     

Synthesis of polyaniline/Ag composite nanospheres through UV rays irradiation method

In this paper, a novel morphology of polyaniline (PANI)/Ag composite nanospheres was obtained through UV rays irradiation method. The structure and morphology of the product were characterized by Fourier transform infrared (FT-IR) spectrum, X-ray diffraction (XRD) pattern, Scanning electron micrograph (SEM) and Transmission electron microscopy (TEM) images, energy-dispersive X-ray (EDAX) analysis, and electron diffraction (ED), respectively. The results showed that the diameters of the PANI nanospheres and the Ag nanofilaments were 10–60 nm and 2–5 nm, respectively. UV rays played an important role for forming PANI nanospheres underpinned by Ag nanofilaments. A potential formation mechanism of PANI nanospheres underpinned by Ag nanofilaments was investigated.     

Synthesis and characterization of water-soluble <Emphasis Type="SmallCaps">l</Emphasis>-cysteine-modified ZnS nanocrystals doped with silver

The water-soluble Ag⁺-doped ZnS nanocrystals surface capped with cysteine (expressed as ZnS:Ag/Cys) were synthesized in aqueous solution by using l-cysteine as surface modifier. The crystal structure, size, shape, component, and spectral properties of ZnS:Ag/Cys nanocrystals were characterized by X-ray power diffraction, transmission electron microscope, energy dispersive X-ray analysis, inductively coupled plasma atomic emission spectrometry, infrared spectrum, UV–Vis absorption spectrum, and photoluminescence spectrum. The results show that the spherical ZnS:Ag/Cys nanocrystals with an average diameter of 2.6 nm have good fluorescent characteristics, their fluorescence intensity is enhanced greatly after doped with Ag⁺. And the sulfur atoms in cysteine molecules are coordinated with metal ions on the surface of the nanocrystals, the cysteine modified on the surface of ZnS:Ag/Cys nanocrystals renders the nanocrystals water soluble and biocompatible. The ZnS:Ag/Cys nanocrystals have potential applications in molecular assembly and biological fluorescence analysis.     

Structural and electrochemical properties of Ag nano-dots combined amorphous Si electrodes for thin-film lithium rechargeable batteries

We have one-pot fabricated Si-based nanocomposite electrodes containing Ag nano-dots for thin-film Li rechargeable batteries by a co-sputtering method. The structural and electrochemical properties of the Si/Ag nanocomposite electrodes are investigated via transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and cycler. The TEM and XRD results show that crystalline Ag nano-dots (approximately 5-9 in size) are well-dispersed within an amorpohous Si matrix. It is shown that the Si/Ag nanocomposite electrode shows much better structural stability than the Si only sample. It is also shown that the Si/Ag nanocomposite electrode shows superior capacity retention compared to the Si only electrode. The results indicate that the presence of the Ag nano-dots is important minimizing the formation of cracks in the electrode, so leading to the better life-time for thin-film Li rechargeable batteries.     

Microstructure and optical properties of Ag-doped ZnO nanostructures prepared by a wet oxidation doping process

Silver-doped zinc oxide (Ag:ZnO) nanostructures were prepared by a facile and efficient wet oxidation method. This method included two steps: metallic Zn thin films mixed with Ag atoms were prepared by magnetron sputtering as the precursors, and then the precursors were oxidized in an O(2) atmosphere with water vapour present to form Ag:ZnO nanostructures. By controlling the oxidation conditions, pure ZnO and Ag:ZnO nanobelts/nanowires with a thickness of ～ 20 nm and length of up to several tens of microns were synthesized. Scanning electron microscopy, transmission electron microscopy, cathodoluminescence and low temperature photoluminescence (PL) measurements were adopted to characterize the microstructure and optical properties of the prepared samples. The results indicated that Ag doping during magnetron sputtering was a feasible method to tune the optical properties of ZnO nanostructures. For the Ag:ZnO nanostructures, the intensity of ultraviolet emission was increased up to three times compared with the pure ones. The detailed PL intensity variation with the increasing temperature is also discussed based on the ionization energy of acceptor in ZnO induced by Ag dopants.