Copper Oxide Nanopowders Research Articles

Ecologic-Biological Effects of Cobalt, Cuprum, Copper Oxide Nano-Powders and Humic Acids on Wheat Seeds

We have determined the comparative efficacy of the effect of cuprum and cobalt nano-particles (30-40 nm), humic acids in an ultra-fine state and mineral salts of these metals used as micro-fertilizers on plants growth and development at concentration from 0.01 till 1000 gr. per hectare norm of viability (gr./h.n.v.). We have conducted some bio-chemical investigations and studied activity of peroxydase and superoxide dismutase ferments in wheat roots and seedlings. The lab tests have determined concentrations when spring wheat plantlets growth and development slows down: for cuprum nano-particles – 500 gr./h.n.v., cobalt – 400 gr./h.n.v., copper sulphate and cobalt chloride – 100 gr./h.n.v. The concentrations of 0.5-10 gr./h.n.v. cuprum and cobalt nano-powders have a well defined stimulating effect. The effect of using the metals nano-particles has been 8-12 % higher than that of the humic acids. Nano-particles have energy to activate metabolic cell processes of plants and concentrations up to 10 gr./h.n.v. can be recommended for the use in agrotechnology that is proved by field tests: wheat yield has increased under the humic acids per 7 %, cuprum and cobalt nano-particles per 17 % and 14 % correspondingly as compared with the control. Cuprum and copper oxide nano-powders (of different chemical substance) at concentrations 0.1 gr./h.n.v.-100 gr./h.n.v. have influenced activity of phytohormones of cytokinin, gibberellin, abscisic acid and indole acetic acids in wheat seedlings. The increase of cuprum nano-powder concentration in 100 times has not caused the decrease of wheat physiologic processes. For copper oxide nano-powders at concentration of 100 gr./ha the hormones activity changes from 22 to 53 % and the use of copper oxide at concentrations higher than 100 gr./h.n.v. is unreasonable. The wheat seeds treatment with 200 nm particles before planting has not changed morpho-physiologic and biochemical indexes as related to the control.

CuO nanopowder for removal of Pb(II) and Zn(II)

Metal oxide nanopowder, namely copper oxide nanopowder, was prepared. The produced metal oxide was characterised and used as a potential adsorbent for removal of lead(II) and zinc(II) from an aqueous solution. The rate of uptake of lead(II) and zinc(II) was found to be rapid in the first 10 min, and after 150 min, the amount of lead(II) and zinc(II) adsorbed was almost constant. The time of equilibrium is independent of initial concentration. The results showed that the removal of lead(II) increased significantly as the pH increased from 2·0 to 6·0 and approached a plateau at a pH range of 6·0–9·0, whereas the removal of zinc(II) increased significantly as the pH increased from 2·0 to 9·0. The adsorption of lead(II) and zinc(II) onto copper oxide followed the Langmuir isotherm. The pseudo-second-order kinetic model provided good correlation for the adsorption of both lead(II) and zinc(II).

Microwave assisted synthesis of copper oxide and its application in electrochemical sensing

Copper oxide nanopowders were prepared using copper acetate as the precursor and polyethylene glycol (PEG) as stabilizer in ethanol medium. The mixture containing copper acetate, sodium hydroxide and PEG was irradiated with microwave and nanometric copper oxide particles were formed within 8 min. The prepared nanoparticles were characterized using x-ray diffraction, UV-vis spectroscopy and scanning electron microscopy. The average particle size was found to be ~ 4 nm. This was used to modify glassy carbon electrode with PVDF & DMF as binder and used for sensing of carbohydrates (glucose and sucrose) and H2O2. The copper oxide nanoparticles showed excellent sensitivity in the range of 0.1 mM to 1 mM when choronoamperometry was carried out at 0.6 V Vs. Ag/AgCl. The observed sensitivity is much higher when compared with conventional micron sized copper oxide particles.

Mechanical and tribological properties of complex-modified material based on ultra high molecular weight polyethylene and CuO

Results of studying nanocomposite materials based on ultra-high-molecular-weight polyethylene filled with copper oxide nanopowder produced in plasma of low-pressure arc discharge are presented. The process of the vacuum-plasma synthesis of powdered composite mixtures, which involves the treatment of powders of the polymer matrix material in a device for synthesizing nanopowders at low temperatures, is described. Results of the experimental study of the specimens are presented.

In Situ XRD, XPS, TEM, and TPR Study of Highly Active in CO Oxidation CuO Nanopowders

Copper(II) oxide nanopowders exhibit a high catalytic activity in CO oxidation at low temperatures. The combination of in situ XPS, XRD, and HRTEM methods was applied to investigate initial steps of CuO nanoparticles reduction, to identify oxygen and copper species and to revealed structural features in the dependence on reducing power of reaction medium. At the oxygen deficient surface of CuO nanopowders the metastable Cu4O3 oxide was formed under the mild reducing conditions −10–5 mbar CO or CO + O2 mixture with oxygen excess. Destruction of Cu4O3 structures in strong reducing medium (P(CO) ≥ 10–2 mbar) or under UHV conditions resulted in the formation of Cu2O which was epitaxially bounded with initial CuO particle. The reversible bulk reduction of CuO nanopowder to Cu2O at temperatures ∼150 °C can be explained by effortless propagation of Cu2O∥CuO epitaxial front inside the nanoparticle. The model of the surface restructuring along the {−111}CuO → {202}Cu4O3 → {111}Cu2O planes under the reduction of CuO nanopowders is proposed. The initial surface of CuO nanopowders is probably distorted and resembles Cu4O3-like structures that facilitates the CuOx ↔ Cu4O3 transition in mild reducing conditions. Such restructuring results in a unique electronic Cu4O3 structure with high oxygen deficiency and low-valence Cu1+ sites stimulating the formation of highly reactive CO and O2 adsorbed species. It was shown that the most active oxygen species on the surface of CuOx is stabilized as O–, which was previously reported in papers by Roberts and Madix in their study of the copper–oxygen systems.

Increasing the wear resistance of aluminium alloy parts with the use of coatings modified with CuO nano-powder

Coatings formed by microarc oxidation and modified by copper oxide nano-powder, as well as microhardness and thickness of coatings have been investigated. Findings of the investigation and results of comparative wear resistance tests are given.

On the initiation of detonation in high explosives by a high-current electron beam

A critical analysis of experimental work on the initiation of high explosives (HE), high-current electron beam of nanosecond duration. It is demonstrated that there is no unambiguous evidence for the initiation of detonation in HE by the electron beams described in the reviewed works. The results of experiments on the effects of a pulsed electron beam on model paraffin samples are presented, which show that the geometric parameters of the sample and the presence of copper oxide nanopowder in it influence its resistance to the action of the beam. It is shown that the main effect on the sample is produced by cathode plasma beam and that the selection of the sample geometry and introduction of nanopowders can enhance the action of a high-current electron beam.

Synthesis and characterization of PVA/YBCO nanocomposite for improvement of solar energy conversion

AbstractThe development of nano‐metal oxide materials with unique optoelectronic properties such as highly solar energy absorption and generation of dense amount of electrons is one of the hottest topics now days. The incorporation of these nanomaterials into polymers results in an improvement of the properties of these polymers. Therefore, the understanding of their electronic properties is an essential demand to introduce these nanocomposites into service life. In this work, Yttrium barium copper oxide (YBCO) nanopowders with a uniform particle size of around 11 nm was prepared, sintered, and blended with polyvinyl alcohol (PVA) by casting technique. The characteristics of the structure and morphology of PVA/YBCO nanocomposite films are studied using X‐ray diffraction and transmission electron microscopy. The influence of YBCO nanoparticles on the thermal stability of PVA showed that the YBCO enhanced the thermal stability and reduced the rate of thermal degradation of PVA nanocomposites. Current–voltage behavior of PVA/YBCO nanocomposite films was measured at different temperatures. An explanation for the charge carrier concentration in the conduction band with the calculation of the barrier height, activation energy, and conversion and their dependence on temperature and applied field is presented.POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers

An experimental study for enhancing the catalytic effects of various copper forms on the oxidation of ferrous iron

In this research the catalytic effect of copper compounds (ionic, oxide and oxide nanopowder) on the oxidation of ferrous iron by aeration was studied experimentally. When copper exists in solution, the oxidation rate of iron(ii) will increase. The experimental results showed that the oxidation rate increases with an increasing copper concentration. From the experimental data it can be determined that the copper oxide nanopowder is the most effective for the oxidation reaction among the used copper forms. Aeration is the most economical oxidation method when water exhibits a high ferrous iron concentration.

An efficient synthesis of alkynyl selenides and tellurides from terminal acetylenes and diorganyl diselenides or ditellurides catalyzed by recyclable copper oxide nanopowder

Herein, we report an efficient method for the synthesis of alkynyl selenides and tellurides from terminal alkynes and diorganyl diselenides or ditellurides using CuO nanopowder as a recyclable catalyst. This new methodology furnished the desired products in good to excellent yields. Furthermore, the catalyst was easily recovered and reused for further catalytic reactions without loss of activity.

Humidity sensing properties of Cu2O-PEPC nanocomposite films

A blend of copper oxide nanopowder (Cu2O), 3 wt.%, and poly-N-epoxypropylcarbazole (PEPC), 2 wt.%, in benzol was drop-casted on glass substrates with pre-deposited surface-type silver electrodes for the fabrication of Cu2O-PEPC nanocomposite thin films. The thicknesses of the Cu2O-PEPC films were in the range of 10–13 μm. The effect of humidity on the electrical properties of the nanocomposite films was investigated by measuring the capacitance and dissipation of the samples at two different frequencies of the applied voltage: 120 Hz and 1 kHz. The AC resistance of the samples was determined from the dissipation values, and the DC resistance was measured directly. The effect of ageing on the humidity sensing properties of the nanocomposite was observed. After ageing, it was observed that at 120 Hz and 1 kHz, under a humidity of up to 86% RH, the capacitance of the cell increased by 85 and 8 times, and the resistance decreased by 345 and 157 times, accordingly, with respect to 30% RH conditions. It was found that with an increase in frequency, the capacitance and resistance of the samples decreased. It is assumed that the humidity response of the cell is associated with the diffusion of water vapors and doping of the semiconductor nanocomposite by water molecules.

Selenides and diselenides containing oxadiazoles: a new class of functionalised materials

A simple and efficient procedure for the synthesis of a new class of organoselenium liquid crystal compounds was developed. The coupling of aryl bromides with elemental selenium was catalysed using copper oxide nanopowder in the presence of potassium hydroxide employing dimethyl sulfoxide as the solvent. This is the first report of the synthesis and characterisation of liquid crystal-based diselenides. Their mesophases were characterised by polarising optical microscopy and differential scanning calorimetry. Compounds 1, 2 and 4b exhibited the smectic A phase. In addition, these compounds showed weak blue fluorescence in solution (λmax. em. 350–405 nm) and a Stokes shift of around 90 nm.

Synthesis of Diselenides or Ditellurides with CuO Nanopowder

Copper(II) oxide nanopowder catalyzed the reaction of elemental selenium and tellurium with aryl and alkyl halides in the presence of KOH to give the corresponding symmetrical di­selenides and ditellurides in up to 96% yield (27 examples).

Wet Synthesis of Copper Oxide Nanopowder

ABSTRACT A simple and efficient synthesis of cuprous oxide and cupric oxide nanoparticles was carried out with controlled surface properties via soft chemistry approach. The monodisperse and versatile Cu2O and CuO nanoparticles were characterized with the help of FT-IR, UV-Vis, TGA/DSC, XRD, SEM-EDX, TEM, and BET. From the XRD analysis, the size of Cu2O and CuO nanoparticles were calculated as 31 nm and 32 nm, respectively, which is calculated with the help of Scherer equation, as supported by TEM. The morphology of the nanoparticles can be controlled by tuning the amount of KOH and nature of solvent. Chemie douce approach is a novel, cheap, and convenient technique suitable for industrial production.

Phosphorus-based nanothermites: A new generation of energetic materials

Thermites are energetic materials that are classically made of a transition metal oxide mixed with a reducing metal. Contrary to explosives, thermites do not detonate because their combustion is relatively slow and their reaction by-products are often solid or liquid. The use of nanoparticles to prepare superthermites is very promising. The dramatic changes observed in their reactivity were reported by numerous recent papers dealing with the use of aluminium as fuel. Red phosphorus is widely used in pyrotechnic devices. Highly explosive compositions are classically obtained by mixing this substance with strong oxidizers such as oxygenated potassium salts (chlorate, nitrate). But to our knowledge, the idea to prepare P-nanothermites with metallic oxide nanoparticles was never reported before. In order to illustrate this new concept of energetic formulations, P-nanothermites were prepared from nickel oxide (NiO), iron oxide (Fe 2O 3), and copper oxide (CuO) nanopowders. The reactivity of these compositions was studied by thermogravimetric analysis, impact and friction tests, electrostatic discharge and high-speed cinematography. P-nanothermites are very insensitive to thermal and impact stress. Their combustion rates strongly depend on the nature of the oxide (NiO <Fe 2O 3⪡CuO). The SEM observation of the microstructure of the residues produced by the combustion clearly indicates that they were formed by the solidification of molten phases. In other words, the energy released by the combustion of P-nanothermites provokes the melting of the reaction products. The temperatures reached are thus high enough to cause the gasification of phosphoric anhydride produced by the combustion. For this reason, P-nanothermites can be considered gas-generating materials.

Copper and copper oxides nanopowders in the oxidative condensations of phenylacetylene and tert-butylacetylene

Transformations of phenylacetylene and tert-butylacetylene in the presence of copper and copper oxide (Cu2O, CuO) nanopowders prepared by gas-phase condensation of copper in argon were studied. The reaction of phenylacetylene with copper oxide nanopowders having different phase compositions in the absence of a solvent at room temperature resulted in oxidative condensation of phenylacetylene and complex formation of the condensation product. The complex undergoes decomposition by the action of acids, bases, and compounds capable of forming complexes. According to the X-ray diffraction data, one of the products is a new “parquet” modification of diphenyldiacetylene. Under analogous conditions, tert-butylacetylene gave rise to a complex mixture of products among which di-tert-butyldiacetylene was identified by gas chromatography-mass spectrometry. No copper complexes with the tert-butylacetylene condensation products were detected.

신촉매 나노 구리산화물을 이용한 심혈관 의약품용 Dihydropyrimidine 제조 연구

The copper oxide nano powders were synthesized by levitational gas condensation (LGC) method, and were applied to catalyst to fabricate 3,4-dihydropyrimidin-2-(1H)-one. Processes of adsorption of Biginelli reaction reagents on the copper nanooxide surface were studied by IR-spectroscopy. It was shown that benzaldehyde coordination, acetoacetic ether on the oxide surface is carried out with participation of carbonyl fragments, urea by N-H bonds which affects positively on the reagents reactivity.

부양가스증발응축법에 의해 제조된 구리산화물 나노분말의 촉매 특성 연구

The copper oxide nano powders were synthesized by levitational gas condensation(LGC) method, and their high heterogeneous catalytic effects of oxidation of 2,3,5-trimethyl-1,4- hydroquinone (TMHQ) and catalase activity were studied. The observation of transmission electron microscopy (TEM) shows that most of these nano powders are uniform in size, with the average particle size of 35 nm. The nano powder consists of mainly <TEX>$Cu_2O$</TEX>, but it is aged to CuO phase. The catalytic effect which was clarified by oxidation of TMHQ and catalase depends on the amount of cuprite phase and the particle size.

Reactivity of nanocrystalline copper oxide and its modification under magnetic field

The influence of magnetic field on the rate of oxidative dehydrogenation of 2,3,5-trimetyl-1,4-hydroquinone (TMHQ) to 2,3,5-trimetyl-1,4-benzoquinone (TMBQ) with catalysts based on copper oxide nanopowders has been investigated. The initial transformation rate of TMHQ and the final product yield greatly increase after a preliminary magnetization of nanopowders. The adsorption ability of Cu-oxide-based nanopowders with respect to ammonia enhances by 1.5 after their magnetization. Physical mechanism of reactivity variation of CuO nanopowders under the influence of weak stationary external magnetic field ( H≤3 kOe) has been proposed. As a result of magnetic field influence, the ferromagnetic regions with modified spin and charge state have appeared in an antiferromagnetic CuO of nonstoichiometric composition. These regions can be new catalytic or adsorption centers.