Formation of Bulk and Two-Dimensional Metal Oxide Nanostructures by Transport Reduction

The use of transport chemical reactions for preparing finely dispersed, two-dimensional struc-tures based on transition metal oxides is considered. A procedure for preparing bulk and film oxide mixtureswith a given content of Fe(II) and Fe(III) is described. The samples are characterized by chemical analysis and Müossbauer spectroscopy. A diagram describing the effect of the support on the degree of iron reduction in a film is presented.     

Investigation of Hydrogen Peroxide Formation After Underwater Plasma Discharge

Plasma Chemistry and Plasma Processing - This paper reports investigations on the formation of hydrogen peroxide resulting from micro-pulse plasma discharges obtained in pin-to-pin configuration...     

Some Mechanisms of SiO2 Micro-tubes Formation in Plasma Jet

A chamotte rod is transformed in vapors through chemical reactions, at temperatures exceeding 5000 K. SiO₂ micro-tubes formation is determined by a low vapor concentration and a stable vapor flow, along the streamlines of the plasma jet, and, respectively, by the difusion processes, in non-stationary regime, inside the liquid membrane. A mass of SiO₂ vapor, in the range of 0.5×10^–8 kg–10×10^–8 kg, allows one to obtain micro-tubes with the outer diameter between 6.2 and 28.8 m and the inner diameter between 3.8 and 12.2 m.     

Synthesis of Copper Oxide Hierarchical Nanostructures

The copper oxide (CuO) hierarchical nanostructures were synthesized by a simple hydrothermal reaction, using copper(II) acetylacetonate and NaOH as the reactants. The morphologies of CuO nanostructures are strongly influenced by the dosage of copper(II) acetylacetonate, alkali concentration and reaction temperature. The possible formation process was also discussed on the basis of time‐dependent experiments. This simple solution‐phase method may be useful for morphological synthesis of other oxides nanocrystals.     

钨氧化物纳米结构的合成与表征

采用溶剂热法以WCl₆作为前体合成出了一维和二维的钨氧化物纳米结构,研究了反应溶剂和前体浓度对钨氧化物物相和形貌的影响并评价了各种钨氧化物纳米结构对NO₂气体的敏感性能。XRD、SEM、TEM和XPS的表征结果表明,通过改变溶剂和调整WCl₆浓度,可分别获得单斜的W₁₈O₄₉纳米棒、W₁₈O₄₉纳米线和WO₃纳米片结构。气敏性能测试结果表明,钨氧化物纳米结构对NO₂气体表现出良好的可逆性,与W₁₈O₄₉纳米棒和WO₃纳米片相比,W₁₈O₄₉纳米线对NO₂具有更高的灵敏度。     

Inhibition of Quorum Sensing,Motility and Biofilm Formation of Pseudomonas aeruginosa by Copper Oxide Nanostructures

Quorum sensing (QS) is the communication between bacterial cells governed by their population density and regulated by the genes controlling virulence factors and biofilm formation. Multiple mechanisms of biofilms are resistive to antimicrobial chemotherapy; therefore novel strategies are required to overcome its limitations. Here, we report the effect of various copper oxide nanostructures (CuO-NSs) on quorum sensing inhibition. The two-dimensional CuO-NSs such as interlaced nanodiscs, nanodiscs and leaf-shaped nanosheets are prepared via a simple chemical method. The Quorum sensing inhibition (QSI) activity of all the CuO-NS are examined using reporter strain Chromobacterium violaceum CV026 and Escherichia coli pSB1142. We found that the CuO-interlaced nanodisc structures exhibit better QSI activity than nanodiscs and leaf-shaped sheets. The interlaced nanodisc structures are inhibited various long-chain N-acyl homoserine lactones (AHLs) mediated QS individually and confirmed by other QS-associated phenomena for Pseudomonas aeruginosa, including biofilm inhibition, inhibition of virulence factors such as pyocyanin, protease production and swarming motility. Thus QSI activity of CuO-NSs is solely dependent on specific shape offering large surface area and more active sites. The CuO-NS is effective quorum sensing inhibitors, which has potential clinical applications in the management of P. aeruginosa associated infections.

     

基于同步辐射光源研究水热合成纳米氧化物的生长机理

纳米氧化物的可控制备是提高其应用性能的前提条件。水热反应目前被广泛用于制备纳米氧化物材料,然而由于水热反应是在密闭环境中进行,很难研究前驱体的溶解过程,溶解后在溶液中的配位情况、晶体成核、生长过程以及形成的中间相,因此,难以实现材料的目标制备。同步辐射具有高强度、高亮度、高准直、宽频谱等诸多优点,通过设计和构建特殊的反应装置,可以应用同步辐射光源原位研究纳米氧化物在水热条件下的生长过程。本文结合本课题组及国际的研究工作介绍了原位反应装置的设计原则,以及基于同步辐射光源的原位X射线衍射(XRD)、X射线吸收精细结构谱(XAFS)和小角X射线散射(SAXS)研究纳米氧化物水热生长机理的最新进展,并展望了其发展趋势。     

The Inherent Electrochemistry of Nickel/Nickel‐Oxide Nanoparticles

The direct detection of nanoparticles is at the forefront of research owing to their environmental and toxicological applications. Herein, we studied the inherent electrochemistry of Ni and NiO nanoparticles and proposed a simple and direct electrochemical method for the determination of the concentrations of both nickel (Ni) and nickel oxide (NiO) nanoparticles in alkaline solution. A highly sensitive voltammetry technique was used to measure the oxidative signal of Ni(OH)₂ that formed spontaneously on the surface of Ni and NiO nanoparticles in alkaline media. Detection limits of 220 μg mL^?1 for Ni and 13 μg mL^?1 for NiO nanoparticles were obtained. Ni and NiO nanoparticles are used as electrode modifiers or as electrochemical signal labels in various biosensing applications. Therefore, methods to rapidly quantify the amount of Ni and NiO nanoparticles are of widespread potential use.     

Applications of Non-precious Transition Metal Oxide Nanoparticles in Electrochemistry

Non-precious transition metal oxide nanomaterials offer numerous opportunities for various cost-effective electrochemical applications. This review article features the design and advancement of such nanomaterials with unique features applied for the fabrication of electrochemical devices. Also, it discusses various new syntheses of transition metal oxide nanoparticles (TMO NPs) via multiple chemicophysical and biological procedures. Further, the novel appliances of the TMO NPs with varying sizes and morphologies are appraised. The advantages and challenges of a number of investigations on the TMO NPs towards electrochemical applications are addressed with their standpoint of cost-effectiveness, applicability, and the efficiency of the introduced nanostructures for the industrial applications.     

水热法制备微纳结构氧化钨

氧化钨(WOx)无机半导体材料因其独特的物理化学性质及在气敏、光催化、电致变色、光致变色和场发射等领域的广泛应用,得到人们的普遍关注。近年来,研究者采用水热法制备出多种不同尺寸和形貌的氧化钨半导体材料。本文结合本课题组在水热法制备WOx粉体方面的最新工作,综述了近十年水热法制备微米及纳米级氧化钨粉体的研究进展,探讨了原料、辅助试剂、表面活性剂、反应时间、反应温度等条件对水热法制备氧化钨粉体材料的影响。最后,对水热法制备氧化钨粉体的发展趋势进行了展望。     

Ultrasound-Induced Formation of CdS Nanostructures in Oil-in-Water Microemulsions

In this study the formation of approximately spherical assemblies of nanocrystalline primary particles of CdS in a CS(2)-water-ethylenediamine (CWE) microemulsion induced by ultrasonic irradiation is described. CS(2) was employed as the sulfur source for CdS and also as the oil phase in the microemulsion. The particles were studied with X-ray powder diffraction, transmission electron microscopy, UV/Vis absorption spectroscopy, and photoluminescence spectroscopy. A blue shift compared to bulk CdS was observed in absorption and photoluminescence spectra. Copyright 2001 Academic Press.     

Synthesis of Aluminum Oxide Nanostructures on the Silicon Surface

Data on the synthesis of aluminum oxide nanostructures on the silicon surface by the oxidation of atomic aluminum layers with a high-frequency inductively coupled oxygen discharge plasma are reported. The conditions for the formation and the properties of aluminum oxide nanolayers were determined. It was found that this method affords oxide films with uniform structure and composition.__________Translated from Khimiya Vysokikh Energii, Vol. 39, No. 5, 2005, pp. 379–381.Original Russian Text Copyright © 2005 by Potapov, Matyuk, Trakhtenberg.     

Functional Nickel Oxide Nanostructures for Ethanol Oxidation in Alkaline Media

Nickel oxide (NiO) nanostructures are employed in the basic medium for the oxidation of ethanol. A variety of NiO nanostructures are synthesized by wet chemical growth method, using different hydroxide (OH^?) ion sources, particularly from ammonia, hexamethylenetetramine, urea and sodium hydroxide. The use of urea as (OH^?) ion source results in flower‐like NiO structures composed by extremely thin nanowalls (thickness lower than 10 nm,), which demonstrated to be the most active for ethanol oxidation. All the samples exhibit NiO cubic phase, and no other impurity was detected. The cyclic voltammetry (CV) curves of NiO nanostructures were found linear over the concentration range 0.1–3.5 mM (R²=0.99) of ethanol, with the limit of detection estimated to be 0.013 mM for ethanol. The NiO nanostructures exhibit a selective signal towards ethanol oxidation in the presence of different members of alcohol family. The proposed NiO nanostructures showed a significant practicality for the reproducible and sensitive determination of ethanol from brandy, whisky, mixture of brandy and rum, and vodka samples. The nanomaterial was used as a surface modifying agent for the glassy carbon electrode and it showed a stable electro‐oxidation activity for the ethanol for 16 days. These findings indicate that the presented NiO nanomaterial can be applied in place of noble metals for ethanol sensing and other environmental applications (like fuel cells).     

Formation of CuCo Alloy From Their Oxide Mixtures Through Reduction by Low-Temperature Hydrogen Plasma

Plasma Chemistry and Plasma Processing - Experimental results of a new method of production of CuCo alloy of composition 95Cu–5Co from the reduction of the mixture of cupric oxide (CuO) and...     

化学气相沉积法制备氧化锡自组装纳米结构

采用化学气相沉积法在镀有5-10 nm厚金膜的SiO2衬底上, 通过控制生长条件, 实现了二氧化锡纳米结构的自组装生长, 成功制备出了莲花状和菊花状的二氧化锡自组装纳米结构. 利用扫描电子显微镜、X射线衍射等表征分析手段对样品的表面形貌、结构及成份进行表征和研究. 并在此基础上, 讨论了两种自组装纳米结构的生长机制.     

Formation of Carbon Nanostructures in Electrolytic Production of Alkali Metals

Carbon-based solid phase containing open and closed multiwalled carbon nanotubes (up to 5% of the total carbon) was found in the waste from industrial production of metallic lithium by electrolysis of lithium chloride melt with graphite electrodes. __________ Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 12, 2005, pp. 1977–1980. Original Russian Text Copyright ? 2005 by Alekseev, Arapov, Belozerov, Osipov, Semenov, Polovtsev, Charykov, Izotova.     

The Structure Formation of Zirconium Oxide Gels in Alcoholic Solution

Zirconium oxide gels were prepared by controlled hydrolysis and condensation of zirconium-n-propoxide in alcoholic solution. After completion of the gelation the aging and drying of the alcogel was observed in situ by Small and Wide Angle X-ray Scattering experiments at room temperature. The xerogels obtained have been annealed at different temperatures to crystallization. The structural changes were observed by using SAXS and WAXS. Structural models reproducing the experimental WAXS data have been simulated by the reverse Monte Carlo method. A comparison between zirconium oxide xerogels obtained under different thermal treatments was made and evidence was found that thermal treatment at higher temperatures and preparation conditions affect the atomic arrangement of these amorphous gels.     

金属氧化物纳米材料的电化学合成与形貌调控研究进展

金属氧化物纳米材料因其丰富的形貌、独特的性能、广泛的应用成为材料合成领域研究的热点.调控金属氧化物纳米材料的形貌对于调变其性能、拓展其应用空间具有重要意义.电化学方法由于操作简单易控、方法灵活多变,因此成为调控金属氧化物形貌的常用方法.本文综述了近年来我们在金属氧化物纳米材料的电化学合成与形貌调控方面已取得的研究结果;总结了不同金属氧化物在电化学过程中晶体生长机制和形貌调控的规律,为实现功能材料的定向合成奠定了基础.     

Plasma Pyrolysis of Ethanol for the Production of Carbon Nanostructures

High Energy Chemistry - An experimental and numerical study of the synthesis of carbon nanostructures by pyrolysis of alcohol in helium and nitrogen plasma jets generated by a DC plasma torch in...     

Formation of Iron Macro-Spheres in Plasma

In this paper the formation mechanism of iron macro-spheres in a plasma medium is dealt with, including the conditions under which such spheres are formed. The geometry of the spheres referred to above depends on the main technological parameters involved in the production of pores. Conditions under which pores occur within macro-spheres are also established. The radii of these pores are sensitive to the velocity distribution within the plasma jet section