Synthesis of Copper Nanoparticles Using Hydrazine in Micellar Solutions of Sodium Dodecyl Sulfate

Moscow University Chemistry Bulletin - The influence of the synthesis conditions and composition of the reaction medium on the size and morphology of copper nanoparticles is studied for the...     

Controlled Synthesis of Narrow-Dispersed Copper Nanoparticles

A controlled synthesis method for preparing narrow-dispersed copper nanoparticles, using water and ethylene glycol as the reaction media respectively, has been reported. In order to obtain pure-phase copper nanoparticles using water, the reaction time of 8 h is essential. Owing to the reduction property of ethylene glycol, the reaction rate using ethylene glycol is higher. In addition, the amount of reduction agent can reduce largely. Polyvinyl pyrrolidone plays great role on the size of copper particles, and the increasing of polyvinyl pyrrolidone concentration attributes to the smaller dimension particles. The mean diameter is about 4 nm when the concentration of polyvinyl pyrrolidone is 0.5 mmol/L. Polyvinyl pyrrolidone acts as the polymeric capping agents in the reaction, preventing the agglomeration of the copper nanoparticles. When water is the reaction medium, Cu²⁺ complex is reduced to Cu⁺ complex firstly, and the further reduction of Cu⁺ forms the pure copper nanoparticle.     

Synthesis of Copper Nanoparticles by Thermal Decomposition of Anhydrous Copper Formate

Highly dispersed anhydrous copper formate obtained by cryochemical synthesis is subjected to thermal decomposition in an atmosphere of hydrogen. X-ray diffraction, PAM, UV-spectroscopy, and lowtemperature adsorption of argon show that the obtained powder contains only copper nanoparticles with a size of 50–200 nm.     

Synthesis and Stabilization of Bismuth Nanoparticles in Aqueous Solutions

Russian Journal of Physical Chemistry A - A technique is developed for the low-temperature synthesis of bismuth nanoparticles in aqueous solutions. UV–Vis spectroscopy, X-ray analysis and...     

Thermal Plasma Synthesis of Superparamagnetic Iron Oxide Nanoparticles

Superparamagnetic iron oxide nanoparticles were synthesized by injecting ferrocene vapor and oxygen into an argon/helium DC thermal plasma. Size distributions of particles in the reactor exhaust were measured online using an aerosol extraction probe interfaced to a scanning mobility particle sizer, and particles were collected on transmission electron microscopy (TEM) grids and glass fiber filters for off-line characterization. The morphology, chemical and phase composition of the nanoparticles were characterized using TEM and X-ray diffraction, and the magnetic properties of the particles were analyzed with a vibrating sample magnetometer and a magnetic property measurement system. Aerosol at the reactor exhaust consisted of both single nanocrystals and small agglomerates, with a modal mobility diameter of 8?C9?nm. Powder synthesized with optimum oxygen flow rate consisted primarily of magnetite (Fe₃O₄), and had a room-temperature saturation magnetization of 40.15 emu/g, with a coercivity and remanence of 26 Oe and 1.5 emu/g, respectively.     

Synthesis,Characterization, and Applications of Copper Nanoparticles

Copper nanoparticles with different structural properties and effective biological effects may be fabricated using new green protocols. The control over particle size and in turn size-dependent properties of copper nanoparticles is expected to provide additional applications. Various methods for the synthesis of copper nanoparticles have been reported including chemical methods, physical methods, biological methods, and green synthesis. Biological methods involve the use of plant extracts, bacteria, and fungi. Commendable work has been done regarding the synthesis and stability of copper nanoparticles. There is a need to summarize the behavior of copper nanoparticles in different media under various conditions. Here, a complete list of the literature on the synthesis of copper nanoparticles, their properties, stabilizing agents, factors affecting the morphology, and their applications is presented. The importance of copper nanoparticles compared to other metal nanoparticles are due to high conductivity. Methods for the synthesis of copper nanoparticles, including green protocols using plants and micro-organisms compared chemical methods, have also been reviewed.     

Interaction of Zinc Oxide and Copper Oxide Nanoparticles with Chlorophyll: A Fluorescence Quenching Study

The present study aims to investigate the interactions of zinc oxide nanoparticles and copper oxide nanoparticles with the major photosynthetic pigment chlorophyll using ultraviolet-visible, steady state, and time resolved laser induced fluorescence spectroscopy. The steady state fluorescence measurements show that zinc oxide and copper oxide nanoparticles quench the fluorescence of chlorophyll in concentration-dependent manner. The Stern-Volmer plot for the chlorophyll-zinc oxide nanoparticles is linear, and the value of quenching constant has been observed to increase with temperature indicating the possibility of dynamic quenching. A decrease in the lifetime of chlorophyll with increase in the concentration of zinc oxide nanoparticles confirms the involvement of dynamic quenching in the chlorophyll–zinc oxide nanoparticle interaction. In the case of copper oxide nanoparticles, the Stern-Volmer plot deviates from linearity observed in the form of upward curvature depicting the presence of both static and dynamic quenching. In addition, the lifetime of chlorophyll decreases with increase in the concentration of copper oxide nanoparticles displaying the dominance of dynamic quenching in the chlorophyll-copper oxide nanoparticle interaction. The decrease observed in the value of binding constant with increasing temperature and negative values of change in enthalpy, entropy, and Gibb’s free energy indicates that van der Waal and hydrogen bonding are the prominent forces during the interaction of chlorophyll with both zinc oxide and copper oxide nanoparticles and that the process is spontaneous and exothermic. The interaction of zinc oxide and copper oxide nanoparticles with chlorophyll occurs through electron transfer mechanism. The obtained results are useful in understanding the sensitization processes involving chlorophyll and zinc oxide and copper oxide nanoparticles.     

铜纳米粒子改性酚醛树脂的合成及其性能

利用甲醛与硫酸铜还原反应,通过添加铜晶核,控制反应液的pH和温度等条件,在酚醛树脂合成体系内原位生成了球形、粒度分布30~50 nm的铜纳米粒子,制得铜纳米粒子改性酚醛树脂,其结构和性能经红外光谱、X-射线衍射、透射电镜、热重分析和冲击试验表征。结果表明：与纯酚醛树脂相比,铜纳米粒子对酚醛树脂的耐热性和韧性有显著影响,初始分解温度提高51 ℃,冲击强度可提高约52%。     

Synthesis and Characterizations of Copper Oxide Nanoparticles Within Zeolite Y

Copper oxide nanoparticles within zeolite Y have been synthesized by a procedure comprising (i) ion-exchange of copper ions into the zeolite, (ii) precipitation of copper ions with sodium hydroxide within the supercages of the zeolite, and (iii) calcination. The products were characterized by X-ray diffraction, scanning electron microscope, energy-dispersive X-ray spectroscopy and Fourier transform infrared (FTIR) spectroscopy. The particle size of CuO products are 20?nm.     

Synthesis of Functional Oxide Nanoparticles Through RF Thermal Plasma Processing

A method of synthesizing functional nanostructured powders through reactive thermal plasma processing has been developed. Nano-sized oxide powders, including titanium dioxide and some functional oxides, were synthesized by the oxidation of liquid precursors. Oxides with the prescribed cation ratio of the liquid precursor can be synthesized with this technique, and it is possible to precisely adjust the chemical composition, which is linked to the appropriate functions of ceramic materials. Quench gases, either injected from the shoulder of the reactor or injected counter to the plasma plume from the bottom of the reactor, were used to vary the quench rate; therefore, the particle size of the resultant powders. The experimental results are well supported by numerical analysis on the effects of quench gases on the flow pattern and temperature field of thermal plasma as well as on the trajectory and temperature history of particles. Plasma-synthesized TiO₂ nanoparticles showed phase preferences different from those synthesized by conventional wet-chemical processes. Nano-sized particles of high crystallinity and nonequilibrium chemical composition were formed in one step via reactive thermal plasma processing. The plasma-synthesized nanoparticles were spherical and hardly agglomerated, and high dispersion properties were observed, i.e., the plasma-synthesized TiO₂ nanoparticles were individually dispersed in water.     

Quenching of Pyrene Fluorescence in Premiceljar Solutions

Abstract

The quenching of the fluorescence intensity of pyrene by KBr has been measured in premicellar solutions of cetyltrimethylammonium bromide (CTAB), sodium lauryl sulfate (SLS) and polyoxyethylene 23-lauryl ether (Brij 35). The association of pyrene with premicellar aggregates is thought to bring the bromide ion closer to the fluorophore and hence results in a greater quenching effect. In 1.0 × 10^?4 M CTAB solutions there is the beginning of “protective” premicellar aggregation. At this stage, 13 times more bromide ion is needed to effect the same degree of quenching as in pure water.     

硫化镉纳米荧光探针荧光猝灭法测定痕量铜

制备了无机纳米溶胶CdS，研究了纳米粒子的大小和荧光性质，以该纳米粒子为探针，建立了荧光猝灭法测定铜离子的新方法。该方法已成功用于人发样品测定，方法简单，快速，选择性好，灵敏度高，在最佳实验条件下，测定铜离子的线性区间为2．0－24．0μg/L，检出限为0．23μg/L。     

Copper Oxide Nanoparticles: Synthesis,Characterization and Their Antibacterial Activity

Copper oxide nanoparticles were prepared by electrochemical reduction method using tetra butyl ammonium bromide (TBAB) as structure directing agent in an organic medium viz. tetra hydro furan (THF) and acetonitrile (ACN) in 4:1 ratio by optimizing current density and molar concentration of the ligand. The reduction process takes place under inert atmosphere of nitrogen over a period of 2 h. Such nanoparticles are prepared using simple electrolysis cell in which the sacrificial anode as a commercially available copper metal sheet and platinum (inert) sheet act as a cathode. The parameters such as current density, solvent polarity, distance between electrodes, and concentration of stabilizers are used to control the size of nanoparticles. The synthesized copper oxide nanoparticles were characterized by using UV–Visible, FT-IR, XRD, SEM–EDS and TEM analysis techniques. The nanoparticles were tested for antibacterial activity against human pathogens like Escherichia coli (E. coli) and Staphylococcus strains and which was proved to be excellent.     

Synthesis and Catalytic Activity of Copper （Ⅱ） Resorcylic Acid Nanoparticles

IntroductionCopper(Ⅱ) resorcylic acid is a type of conven-tional burning rate catalyst commonly used in solid pro-pellant. Burning rate is considered as an important pa-rameter in the performance of solid propellant. Recentliterature has shown that the b…     

Synthesis and Characterization of Titanium Oxide Nanoparticles by Plasma in Contact with Liquid

Plasma Chemistry and Plasma Processing - Two types of plasma in contact with water were employed for the synthesis of mixed-phase TiO2 in a liquid. This is glow discharge with a metal cathode and...     

Photochemical Synthesis of Anisotropic Silver Nanoparticles in Aqueous Solutions in the Presence of Sodium Citrate

The rapid one-step photochemical synthesis of anisotropic silver nanoparticles (ANPs) is reported. Silver ANPs were prepared from silver nitrate by a citrate route in aqueous solutions at room temperature under exposure to unfiltered light of a DRK 120 high-pressure mercury lamp. The silver ANPs form through one-electron reduction of the silver cation in its chelate complex with the production of sodium citrate photolysis. In the course of synthesis, small charged silver clusters and nanoparticles are formed first, which are then stabilized by citrate ions. Key factors that influence the synthesis of silver ANPs and their further transformation have been determined.