Temperature driven morphological changes of hydrothermally prepared copper oxide nanoparticles

The size and shape of nanocrystals have a strong effect on the optical, electrical and catalytic properties. Therefore, controlling the size, shape and structure of nanocrystals is technically important. The controlled synthesis of CuO nanostructures was achieved using a hydrothermal process by simply controlling the precipitation reaction temperature between copper nitrate trihydrate and sodium hydroxide. The Scanning Electron Microscopy (SEM), EDS, XRD, and FTIR analysis revealed that the synthesized product at 200 °C is of pure copper oxide particles. From Scherrer formula, the prepared CuO particles varied approximately 3–7 nm in size simply by varying the reaction temperature. The synthesized particles exhibited a regular flake like morphology and had a uniform size distribution. The morphology and size depend on the reaction conditions. Copyright © 2008 John Wiley & Sons, Ltd.     

Zinc and copper oxide nanoparticles decrease synaptosomal glutamate uptake: an in vitro study

Nanoparticles (NPs) are considered as an important environmental risk factor for cognitive impairments and neurodegenerative disorders. Recent evidences have reported a glutamatergic system response against air-borne NPs. Zinc and copper oxides (ZnO and CuO) NPs are the most common metal oxide NPs in industries. The effects of these NPs on hippocampal voltage-dependent ion channels and spatial cognition have been previously studied. However, there is a lack of evidence regarding the effects of ZnO and CuO NPs on glutamatergic synapse neurotransmission in central nervous system. In the present study, the effects of ZnO and CuO NPs on glutamate (Glu) release and uptake have been investigated in isolated nerve terminals (synaptosomes). Our findings have shown that, even in high doses of ZnO and CuO NPs, no significant effect on Glu release is observed. However, a decrease has been observed in uptake of Glu. Hence, ZnO and CuO NPs can be considered as hazardous agents inducing neurodegenerative disorders through Glu excitotoxicity.     

Protective effect of total flavonoids from Spirodela polyrrhiza (L.) Schleid on human umbilical vein endothelial cell damage induced by hydrogen peroxide

In this study, we determined the protective effect of total flavonoids from Spirodela polyrrhiza (L.) Schleid (STF), which is a kind of traditional Chinese medicine, on human umbilical vein endothelial cells (ECV-304) damage induced by hydrogen peroxide (H(2)O(2)). Treated with 1mmol/L H(2)O(2) for 1h, the viability of ECV-304 cells markedly decreased. However, pretreatment with 10-50mug/mL STF resulted in a significant recovery. The survival rate of ECV-304 increased from 21.98% (only treated with 1mmol/L H(2)O(2)) to 64.74% (pretreated with 50microg/mL STF), which accompanied with the amounts of malondialdenhyde (MDA) decreasing from 1.6883nmol/L to 0.9628nmol/L. Furthermore, compared with control group, the 50mumol/L STF pretreatment enhanced the total antioxidant capacity (T-AOC) by 4.49 times, increased the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) by 85.12%, 158.94% and 94.5%,respectively, and increased the content of nitric oxide (NO) by 116.55%.Taken together, STF protect ECV-304 cells against H(2)O(2) damage by enhancing the antioxidant ability and increasing NO production.     

Electrospun copper oxide nanoparticles as an efficient heterogeneous catalyst for N-arylation of indole

The N-arylation of indoles with a variety of aryl bromides is reported using copper oxide nanoparticles as a heterogeneous catalyst. These copper oxide nanoparticles, which were produced in a novel, facile, and scalable fashion via an electrospinning technique, resulted in an excellent product yield under mild conditions. Moreover, the catalyst was easily recovered and reused several times without significant loss of activity.     

Determination of thiourea using a carbon paste electrode decorated with copper oxide nanoparticles

We report on a novel sensor for the electrochemical determination of thiourea (TU). It is based on an active carbon paste electrode modified with copper oxide nanoparticles. The modified electrode and the electrochemical properties of thiourea on its surface were investigated using cyclic voltammetry and differential pulse voltammetry. Under optimized conditions, the detection limit is 20 μg?L^?1 of TU. The method was applied to the determination of thiourea in fruit juice, orange peel and industrial waste water.

Reactivity of nanoparticles; interaction between zinc and copper oxide nanoparticles and iron ions in an alkaline medium

The reactivity of zinc and copper oxide nanoparticles was investigated upon their interaction with iron oxides. It was ascertained that, depending on the reaction conditions, nanoparticles of zinc and copper ferrites (ZnFe₂O₄ and CuFe₂O₄) or core/shell nanoparticles (Fe₃O₄/ZnO) are produced. Size, composition, and structure of the resulting nanoparticles were determined by transmission electron microscopy and X-ray diffraction analysis. The average size of zinc and copper ferrite nanoparticles was ascertained to be 9–10 and 2–3 nm, respectively. For core/shell Fe₃O₄/ZnO nanoparticles, the average size is 20 nm. It was experimentally proved that the photoluminescence radiative characteristics of ZnO nanoparticles are retained in core/shell Fe₃O₄/ZnO nanoparticles.     

High-performance sensor based on copper oxide nanoparticles for dual detection of phenolic compounds and a pesticide

The development of nanomaterials for use as bio-recognition elements is important in the evolution of biosensing systems. In the present article we present a sensing system based on copper oxide nanoparticles (CuO NPs) for the detection of phenolic compounds and pesticides. This sensor takes advantage of the interactions of CuO NPs with toxic compounds that in turn generate an electrochemical signal related to the concentration of the pollutants.     

Facile in situ synthesis of nanofluids based on ionic liquids and copper oxide clusters and nanoparticles

Two stable nanofluids comprising of mixed valent copper(I,II) oxide clusters (<1 nm) suspended in 1-butyl-3-methylimidazolium acetate, [C(4)mim][OAc], and copper(II) oxide nanoparticles (<50 nm) suspended in trioctyl(dodecyl)phosphonium acetate, [P(8 8 8 12)][OAc], were synthesised in a facile one-pot reaction from solutions of copper(II) acetate hydrate in the corresponding ionic liquids. Formation of the nanostructures was studied using (13)C NMR spectroscopy and differential scanning calorimetry (DSC). From a solution of Cu(OAc)(2) in 1-ethyl-3-methylimidazolium acetate, [C(2)mim][OAc], crystals were obtained that revealed the structure of [C(2)mim][Cu(3)(OAc)(5)(OH)(2)(H(2)O)]·H(2)O, indicating the formation of copper hydroxo-clusters in the course of the reaction. Synthesised nanostructures were studied using transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Physical properties of the prepared IL-nanofluids were examined using IR and UV-VIS spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and densitometry.     

Acoustical and thermodynamical parameters of aluminium oxide nanoparticles dispersed in aqueous ethylene glycol

In the present work aluminium oxide (Al₂O₃) nanoparticles were synthesised by the precipitation method using AlCl₃ as a starting material. The synthesised nanoparticles were characterised by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). These nanoparticles have been dispersed in base fluid, an aqueous solution of ethylene glycol (EG). Density (ρ), ultrasonic velocity (u), and viscosity (η) for these nanofluids have been measured at different concentrations as a function of temperature (T = 303.15 K, 308.15 K, and 313.15 K). Using their values various acoustical and thermodynamical parameters have been computed.     

Versatility of hydrophilic and antifouling PVDF ultrafiltration membranes tailored with polyhexanide coated copper oxide nanoparticles

Hydrophilic poly(vinylidene fluoride) (PVDF) nanocomposite ultrafiltration (UF) membranes with excellent antifouling and antibiofouling characteristics are fabricated by employing polyhexanide coated copper oxide nanoparticles (P–CuO NPs). The presence of P–CuO NPs is played a significant role in altering the PVDF membrane matrix and probed by XRD, FTIR, FESEM and contact angle analysis. The PVDF/P–CuO nanocomposite membranes exhibited an outstanding antifouling performance indicated by the superior pure water flux, effective foulant separation and maximum flux recovery ratio during UF experiments as a result of the formation of the hydrophilic and more porous membrane due to the uniform distribution of P–CuO NPs. Particularly, the PVDF/P–CuO-3 membrane showed higher PWF of 152.5 ± 2.4 lm⁻²h⁻¹ and porosity of 64.5% whereas the lower contact angle of 52.5°. Further, it showed the higher rejection of 99.5 and 98.4% and the flux recovery ratio of 99.5 and 98.5% respectively for BSA and HA foulants, demonstrated its increased water permeation, foulant separation and antifouling behavior. Further, the decent antibacterial activity is showed by the PVDF/P–CuO nanocomposite membranes with the formation of halo-zone around the membrane when exposed to the bacterial medium demonstrated that, by this process an antibacterial water treatment membrane can be developed by simple phase inversion technique with good membrane stability.     

Superlattice of octanethiol-protected copper nanoparticles

The synthesis and spectroscopic characterizations of size-controlled Cu nanoparticles forming self-assembled 2D superlattices with hexagonal packing are described. The scanning electron microscopy (SEM), nuclear magnetic resonance (NMR), thermal gravimetric analysis (TGA), and electron spectroscopy for chemical analysis (ESCA) techniques were used to characterize the octanethiol-protected copper nanoparticles.     

Green synthesis of copper oxide nanoparticles CuO NPs from Eucalyptus Globoulus leaf extract: Adsorption and design of experiments

The study is concerned with synthesizing copper oxide nanoparticles with leaf extract Eucalyptus Globoulus. The results of scanning electron microscopy (SEM) and dynamic light scattering (DLS) revealed that the green synthesized copper oxide nanoparticles are spherical and have a mean particle size of 88 nm, with a negative zeta potential of ?16.9 mV. The XRD graph showed the crystalline and monoclinic phases of CuO nanoparticles. The average crystalline size around 85.80 nm was observed by the Debye–Scherrer formula. The adsorption characteristics of the nano-adsorbents were investigated using methyl orange, and the adsorption efficiency at room temperature attained 95 mg/g. Copper oxide nanoparticles (CuO NPs) adsorb methyl orange dye most effectively at pH 4.5 when the dye is applied in quantities of 0.04 g/50 mL. Box–Behnken design (BBD) in response surface methodology (RSM) was used to optimize various process parameters, such as pH solution (X₁: 2 – 11), adsorbing dose (X₂: 0.01 – 0.08 g/L), [MO] dye concentration (X₃: 10 – 80 mg/L). Overall, the adjusted coefficient of determination (R²) value of 0.99 demonstrated that the used model was quite appropriate, and the chosen RSM was effective in optimization the decolorization conditions of MO.     

Stereoselective single (copper) or double (platinum) boronation of alkynes catalyzed by magnesia-supported copper oxide or platinum nanoparticles

Copper(II) oxide nanoparticles supported on magnesia have been prepared from Cu(II) supported on magnesia by hydrogen reduction at 400 °C followed by storage under ambient conditions. X-ray photoelectron spectroscopy of the material clearly shows that immediately after the reduction copper(0)-metal nanoparticles are present on the magnesia support, but they undergo fast oxidation to copper oxide upon contact with the ambient for a short time. TEM images show that the catalytically active CuO/MgO material is formed of well-dispersed copper oxide nanoparticles supported on fibrous MgO. CuO/MgO exhibits a remarkable catalytic activity for the monoborylation of aromatic, aliphatic, terminal, and internal alkynes, the products being formed with high regio- (borylation at the less substituted carbon) and stereoselectivity (trans-configured). CuO/MgO exhibits complete chemoselectivity towards the monoborylation of alkynes in the presence of alkenes. Other metal nanoparticles such as gold or palladium are inactive towards borylation, but undergo undesirable oligomerization or partial hydrogenation of the C≡C triple bond. In contrast, platinum, either supported on magnesia or on nanoparticulate ceria, efficiently promotes the stereoselective diborylation of alkynes to yield a cis-configured diboronate alkene. By using platinum as the catalyst we have developed a tandem diborylation/hydrogenation reaction that gives vic-diboronated alkanes from alkynes in one pot.     

Tailored coordination nanoparticles: assessing the magnetic single-domain critical size

Negatively charged nanocrystals of the magnetic coordination network CsNiCr(CN)(6) were prepared in water through a seed-mediated growth with a few atomic layers accuracy and final sizes tailored from 6 to 30 nm. A lower limit of the magnetic single-domain critical size was determined to be around 15 nm possessing a blocking temperature above 20 K.     

Magnetic fluid hyperthermia: focus on superparamagnetic iron oxide nanoparticles

Due to their unique magnetic properties, excellent biocompatibility as well as multi-purpose biomedical potential (e.g., applications in cancer therapy and general drug delivery), superparamagnetic iron oxide nanoparticles (SPIONs) are attracting increasing attention in both pharmaceutical and industrial communities. The precise control of the physiochemical properties of these magnetic systems is crucial for hyperthermia applications, as the induced heat is highly dependent on these properties. In this review, the limitations and recent advances in the development of superparamagnetic iron oxide nanoparticles for hyperthermia are presented.     

纳米氧化铈、铁酸铜的乳化燃烧合成及其光催化性能

采用金属硝酸盐、硝酸铵和油相在乳化剂作用下制备成油包水的乳状液,以燃烧的方式制备了纳米氧化铈(CeO_2)和铁酸铜(CuFe_2O_4),并成功将它们负载到氧化石墨烯(GO)上.实验结果显示:以燃烧法合成的CeO_2和CuFe_2O_4纳米粒子较为纯净,平均粒径分别约为29.1和13.5nm;二者分别负载到GO上后,团聚现象得到一定程度改善,光响应能力得到增强.在汞灯照射下,催化剂GO-CeO_2、GO-CuFe_2O_4对罗丹明B的2h光降解率分别可达92.3%、98.1%.这表明所合成样品GO-CeO_2、GO-CuFe_2O_4具有优异的光催化活性.     

Significantly enhanced electromagnetic interference shielding effectiveness of montmorillonite nanoclay and copper oxide nanoparticles based polyvinylchloride nanocomposites

In the present study, montmorillonite (MMT) nanoclay and copper oxide (CuO) nanoparticles (NPs) reinforced polyvinylchloride (PVC) based flexible nanocomposite films were prepared via solvent casting technique. Using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscopy (SEM) and thermo-gravimetric analysis (TGA), the structural, morphological and thermal properties of PVC/MMT/CuO nanocomposite films with various loadings of CuO NPs and MMT were investigated. These studies suggested that by the addition of dual nanofillers in the polymer matrix some structural modifications occurred owing to the homogenous dispersion of MMT and CuO NPs within the PVC matrix. The TGA results reveal that the addition of CuO NPs and MMT considerably improved the thermal stability of the nanocomposites. The EMI shielding effectiveness (SE) of nanocomposites was examined in the X-band (8–12 GHz) and Ku-band (12–18 GHz) frequency regions. The EMI SE values were found to be −30 dB (X-band) and −35 dB (Ku-band) for nanocomposites containing 0.3 wt% of CuO NPs and 4.7 wt% of MMT respectively while the shielding was found to be absorption dominant. These results emphasize that PVC/MMT/CuO nanocomposite films can be used as a potential EMI shielding material.     

Amperometric determination of L-tyrosine by an enzymeless sensor based on a carbon ceramic electrode modified with copper oxide nanoparticles

We report on the electrochemical formation of copper oxide nanoparticles (CuO-NPs) at a carbon ceramic electrode (CCE) as a highly-porous substrate. A copper film was deposited on the surface of the CCE and derivatized in situ to give CuO-NPs by potential cycling between ?0.8 and 0.35?V in strongly alkaline solution. The electrode was characterized by scanning electron microscopy and cyclic voltammetry. The CuO-NPs exhibited excellent electrocatalytic activity toward the oxidation of L-tyrosine (L-Tyr) in responding linearly in the 2 to 1,350???M concentration range, an associated detection limit (S/N?=?3) of 160?nM, and a sensitivity of 0.61?A?M^?1?cm^?2.

Zinc oxide nanoparticles immobilized on graphene flake

Interactions of ZnO nanoparticles with graphene oxide in isopropanol were studied; graphene oxide was shown to perform as an efficient substrate to immobilize zinc oxide nanoparticles on its surface. Interactions of nanocomposites consisting of graphene oxide-zinc oxide nanoparticles with supercritical isopropanol were studied. The conversion of graphene oxide into graphene does not appreciably changes the composition, morphology, or structure of ZnO nanoparticles.