反相微乳液助水热法可控合成FeNi3合金纳米结构

利用水热法处理表面活性剂/正辛烷/正己醇/水四元微乳体系成功合成FeNi3合金纳米结构. 通过改变表面活性剂的用量和类型来调控产物粒径与形貌. 当表面活性剂为聚乙二醇4000(PEG4000)时, 产物为球状, 粒径约为75 nm. 当表面活性剂为十六烷基三甲基溴化铵(CTAB)时, 产物为海胆状.单个海胆状颗粒是由许多纳米棒构成, 其直径约为42 nm, 长度为0.4-1.2 μm. 利用X射线粉末衍射(XRD), 穆斯堡尔谱, 扫描电子显微镜(SEM), 透射电子显微镜(TEM), 选区电子衍射(SAED), 多功能磁天平(MMVFTB)等测试手段对产物的组成、形貌和磁性能进行了表征. 球状和海胆状的FeNi3样品在室温下呈现典型的铁磁性特征, 其饱和磁化强度(Ms)值分别为114.4和97.4 emu·g-1, 矫顽力(Hc)值分别为94.0和329.0 Oe.     

Electroanalysis of Norepinephrine at Bare Gold Electrode Pure and Modified with Gold Nanoparticles and S‐Functionalized Self‐Assembled Layers in Aqueous Solution

Gold nanoparticles (Au‐NPs), cystamine (CA) and 3,3′‐dithiodipropionic acid (DTDPA) modified gold bare electrodes were applied in voltammetric sensors for simultaneous detection of norepinephrine (NEP), ascorbic (AA) and uric (UA) acids. A linear relationship between norepinephrine concentration and current response was obtained in the range of 0.1 μM to 600 μM M with the detection limit ≤0.091 μM for the electrodes modified at 2D template and in the range of 0.1 μM to 700 μM M with the detection limit ≤0.087 μM for the electrodes modified at 3D template The results have shown that using modified electrodes it is possible to perform electrochemical analysis of norepinephrine without interference of ascorbic and uric acids, whose presence is the major limitation in norepinephrine determination at a bare gold electrode. The modified SAMs electrodes show good selectivity, sensitivity, reproducibility and high stability.     

Electrodeposited Silver Nanoparticles on Carbon Ionic Liquid Electrode for Electrocatalytic Sensing of Hydrogen Peroxide

Silver nanoparticles (narrowly dispersed in diameter) were electrodeposited on carbon ionic liquid electrode (CILE) surface using a two‐step potentiostatic method. Potentiostatic double pulse technique was used as a suitable and simple method for controlling the size and morphologies of silver nanoparticles electrodeposited on CILE. The obtained silver nanoparticles deposited on CILE surface showed excellent electrocatalytic activity (low overpotential of ?0.35 V vs. Ag/AgCl) towards reduction of hydrogen peroxide. A linear dynamic range of 2–200 μM with an experimental detection limit of 0.7 μM (S/N=3) and reproducibility of 4.1% (n=5) make the constructed sensor suitable for peroxide determination in aqueous solutions.     

Electrocatalytic Reduction of Hydrogen Peroxide by Nanostructured Bimetallic Films of Metalloporphyrins

We report the sequential electrochemical deposition of bimetallic films of porphyrins onto gold nanoparticles, previously deposited by SAM on gold surface. SEM analysis of EAu/polyFeCuPP and EAu/cys/AuNp/polyFeCuPP showed a heterogeneous distribution of material aggregates in the former (ca. 0.1–1 μm), whereas the nanocomposite film exhibits a highly microporous structure in the micrometer diameter range. The sensitivity for H₂O₂ detection increased four times (609±6 mA M^?1 cm^?2 vs. 157±3 mA M^?1 cm^?2) with a linear relationship in the range of 1×10^?5–2×10^?3 M. The application of the particulate material to the first‐generation biosensor of glucose is described.     

Topical application of solubilized Reseda luteola extract reduces ultraviolet B-induced inflammation in vivo

We investigated the skin tolerance and anti-inflammatory potential of a nanoparticular solubilisate of a luteolin-rich Reseda extract (s-RE) in two independent studies in vivo. Reseda luteola extract containing 40% flavonoids was solubilized with polysorbate, resulting in product micelles with a diameter of 10 (±1.5) nm. Standardized inflammation was induced by irradiating test areas on the back of healthy volunteers with defined doses of ultraviolet B (UVB). In the first study different concentrations of s-RE were tested in 10 volunteers to evaluate dose-dependency of anti-inflammatory effects of s-RE. In the second randomized, double-blind, placebo-controlled study a defined concentration of s-RE (2.5% w/w) was tested in 40 volunteers in comparison to the vehicle (glycerol) and hydrocortisone (1% w/w). s-RE dose-dependently reduced UVB-induced erythema when applied 30 min before irradiation. To a lesser extent, topical application of s-RE after irradiation also reduced UVB-induced erythema. s-RE was as effective as hydrocortisone, whereas the vehicle had no effect. Occlusive application of s-RE on non-irradiated test sites did not cause any skin irritation. Due to excellent skin tolerance combined with potent anti-inflammatory properties s-RE bears potential especially for the prevention but also for the treatment of inflammatory skin conditions such as UV-induced erythema.     

Real-time probing of the growth dynamics of nanoparticles using potentiometric ion-selective electrodes

This Communication demonstrates the ability of potentiometric ion-selective electrodes (ISE) to probe the growth dynamics of metal nanoparticles in real-time. The new monitoring capability is illustrated using a solid-contact silver ISE for monitoring the hydroquinone-induced precipitation of silver on gold nanoparticle seeds. Potential-time recordings obtained under different conditions are used to monitor the depletion of the silver ion during the nanoparticle formation and shed useful insights into the growth dynamics of the nanoparticles. Such potentiometric profiles correlate well with the analogous optical measurements. The new real-time electrochemical probing of the particle growth process reflects the direct, rapid and sensitive response of modern ISE to changes in the level of the precipitated metal ion from the bulk solution and holds considerable promise for probing the preparation of different nanoscale materials.     

New “smart” poly(NIPAM) microgels and nanoparticle microgel hybrids: Properties and advances in characterisation

This review is devoted to poly(NIPAM) based microgels and nanoparticle/polymer hybrid microgels. It tries to give a brief overview of recent developments with respect to new systems and experimental methods. The properties of these fascinating materials are reported together with advances in their characterisation by imaging and scattering techniques. Aspects of their application in the area of mesotechnology will also be discussed.     

Simple synthesis and spectroscopic studies on cobalt added ZnO nanocrystals

Cobalt doped zinc oxide nanoparticles were prepared through simple wet chemical method. X-ray diffraction studies confirm the prepared particles are in wurtzite structure. Scanning Electron Microscopy studies show the shape and morphology of the particles. To identify the presence of cobalt in ZnO, Energy Dispersive X-ray analysis was done. Optical absorption measurements show the presence of exciton peak at 375 nm. Photoluminescence studies were done with the excitation wavelength of 330 nm, which shows the emission because of exciton recombination and oxygen vacancy.     

Galvanic synthesis of copper selenides Cu2 − x Se and CuSe in alkaline sodium selenosulfate aqueous solution

Spherical copper selenide nanoparticles (NPs) were prepared by a simple reaction of sodium selenosulfate with metal copper at room temperature in alkaline Na₂SeSO₃ aqueous solution. It is a galvanic process that operates on a coupled anodic copper oxidation and selenosulfate reduction. 1-Thioglycerol is found to catalyze this reaction. With gold and graphite as the positive electrodes, nanocrystallites of nonstoichiometric copper selenide (Cu_2 − x Se) and stoichiometric copper selenides (CuSe) were produced, respectively. The XRD study shows that the produced CuSe and Cu_2 − x Se are in the pure hexagonal phase and clausthalite phase, respectively. Transmission electron microscopy images show that the diameters of the produced CuSe and Cu_2 − x Se NPs are in the range of 10∼20 and 5∼15 nm, respectively.     

Preparation,Characterization and Electrochemical Behavior of Pd‐Au Alloy Incorporated into Zeolites/Graphite Electrodes

The present article reports the preparation of Pd‐Au alloy incorporated into NaY zeolites layer via simple immersion technique. Pd‐Au particles were incorporated into zeolites cages via Co‐impregnation or alternate impregnation of metal ions. Cyclic voltammetry was used to evaluate the state of the modified electrodes in alkaline media. Surface morphology as well as elemental composition of the modified layer were examined using Scanning electron microscopy (SEM) and energy dispersive X‐ray (EDX).