CuO Nanopowder Research Articles

Prepared the Activator of Rare Earth–Doped CuO Nanopowder by Stearic Gel Method

The nanocomposite powder of rare earth-doped CuO were prepared by the stearic gel method and characterized by means of X-ray (XRD) and, transmission electron microscopy (TEM) and, scanning electron microscope (SEM) and Infrared Radiation (IR). Microscopic investigation of the nanopowder was measured by Atomic Force Microscope (AFM). The results showed that the grain sizes are in the order of nanometers, approximately 10 nm, 12 nm, 22 nm, 32 nm and 40 nm for the nanopowder deposited at 600oC, 650oC, 700 oC, 750 oC and 800 oC, respectively. The grains grew up with the increase of sintering temperature. There were some agglomeration and self-assembly phenomenon in the particles. Based on the IR results, it clearly showed that the vibration kurtosis was changed with the different sintering temperature.

Comparative study of magnesia‐supported highly‐dispersed CuO solids prepared by different methods in CO oxidation

Magnesia‐supported highly‐dispersed CuO solids were prepared by impregnation and mechanical mixing of CuO nanopowders with MgO. Additionally, ultrasound and mechanochemical treatment of CuO nanopowders mixed with MgO was performed. TEM and XRD studies indicate that the size of the CuO nanoparticles in solids depends on the method of preparation. Catalytic tests of these solids in the CO oxidation show that varying the method of catalyst preparation changes the temperature of the 100 % conversion CO by more than 130 °C. Fabrication of the CuO‐MgO catalysts via an easy mixing process using CuO nanopowder and cubic MgO gives the most active catalyst. Mechanochemical and/or ultrasound treatments lead to catalyst deactivation. Our results show that method of the catalyst preparation influences the catalyst performance mainly through varying the CuO nanoparticle size and CuO‐support interaction.

Efficiency enhancement of p-CuO/n-Si heterojunction solar cells: Impact of annealing on the photovoltaic properties of Vapour-Liquid-Solid (VLS) grown ultra-thin CuO film

This work investigates the impact of annealing on the performance of p-CuO/n-Si heterojunction, where the CuO nano-powder is synthesized by using CBD technique and subsequently used to grow CuO thin films by employing vapour-liquid-solid method. Investigations are performed in terms of film morphology, crystallite structure and photovoltaic performances. The photovoltaic parameters including open circuit photo-generated voltage, short-circuit current density and energy conversion efficiency are estimated by measuring the current-voltage characteristics of p-CuO/n-Si diodes under illumination. The power conversion efficiencies are obtained to be 0.26% and 6.13% for the as-deposited and annealed films respectively, for a power input of 0.037 mW/cm2.

Synthesis of a complex nanostructure of CuO via a coupled chemical route

In the present study, we report the preparation of CuO nanopowder by using a coupled chemical method, namely sol-gel/hydrothermal processes. The product of the first stage process (i.e. sol-gel) was a nanocomposite of Cu(OH)2/SDS, while the product of the second stage (i.e. hydrothermal) was a pure phase of CuO nanopowder. The structure and morphology of the prepared samples was characterized using x-ray diffraction analysis, scanning electron microscopy, Fourier transform infrared spectroscopy and energy dispersive x-ray analysis. The CuO nanostructure assemblies obtained are similar to flower-like structures with intricate geometry. The size of CuO prolate spheroids ranges from 500 nm to 700 nm when they are measured according to a major axis, while they range from 120 nm to 450 nm when the measurement is carried out according to a minor axis. The mechanism growth was explained on the basis of chemical reactions and the role of each reactant in the formation the CuO nanostructure.

Solution‐dispersed CuO nanoparticles as anode buffer layer in inverted type hybrid organic solar cells

A solution‐dispersed copper oxide (CuO) nanoparticles anode buffer layer has been investigated to improve the efficiency of inverted type hybrid organic solar cell (OSC) based on zinc oxide (ZnO)/poly(3‐hexylthiophene) (P3HT) with and without an electron acceptor, (6,6)‐phenyl‐C61‐butyric acid methyl ester (PCBM). The photoactive layer consisted of P3HT was spin‐coated onto the ZnO nanorod arrays that were grown on fluorine tin oxide (FTO) substrate. The CuO nanopowders dissolved in 1‐butanol, ethanol, and 1‐propanol were then spin‐coated onto the photoactive layer, followed by the deposition of silver (Ag) using thermal evaporation technique. The contact angle measurements indicate that CuO nanopowders dispersed in 1‐butanol showed the highest wettability on the photoactive layer surface, which results in better photovoltaic performance compared to the other solvents (ethanol and 1‐propanol). For further investigation, the CuO anode buffer layer spin coating speed dependence of inverted type hybrid OSC based on ZnO/P3HT:PCBM was also studied. The CuO layer deposition on top of photoactive layer was optimized by using various spin coating speeds of 1000, 2000, and 3000 rpm. The optimum PCE of 2.24% was achieved at a spin coating speed of 2000 rpm, as a result of uniform and complete coverage of CuO on the photoactive layer.

Characterization of nano-powder grown ultra-thin film p-CuO/n-Si hetero-junctions by employing vapour-liquid-solid method for photovoltaic applications

In this work, the CuO nano-powder has been synthesized by employing chemical bath deposition technique for its subsequent use to grow ultrathin film (20nm) of p-CuO on n-Si substrate for the fabrication of p-CuO/n-Si hetero-junction diodes. The thin CuO film has been grown by employing vapour-liquid-solid method. The crystalline structure and chemical phase of the film are characterized by employing field-emission scanning electron microscopy and X-ray diffraction studies. Chemical stoichiometry of the film has been confirmed by using energy dispersive X-ray spectroscopy. The potential for photovoltaic applications of such films is investigated by measuring the junction current-voltage characteristics and by extracting the relevant parameters such as open circuit photo-generated voltage, short circuit current density, fill-factor and energy conversion efficiency.

A procedure for processing of pregnant leach solution (PLS) produced from a chalcopyrite-ore bio-heap: CuO Nano-powder fabrication

The present research work describes a facile and industrial-friendly procedure for producing high quality CuO nano-powder from a PLS of a low-grade chalcopyrite-ore bioleaching. The PLS containing lower than about 1gCu/L (obtained from the ore bioleaching) was used as the feed for the procedure in which firstly the iron and other impurities was removed from the PLS, and next the pure copper–ammonia complex was selectively formed from the PLS. Then, the complex was transformed to the precursor (Copper Hydroxide Sulfate Hydrate (Cu2.5(OH)3(SO4)·(H2O)2)) at the room temperature. Finally, the precursor was dried at 60°C overnight to obtain pure CuO nano-powder (average crystalline size of about 19nm). The results were confirmed by the characterization analyses: XRD, SEM/EDS, elemental mapping, TEM, FTIR, chemical analyses, and XRF.

Electrochemical properties of hollow copper (II) oxide nanopowders prepared by salt-assisted spray drying process applying nanoscale Kirkendall diffusion

The synthesis of hollow CuO nanopowders by a salt-assisted spray drying process applying nanoscale Kirkendall diffusion is introduced. The electrochemical properties of the hollow CuO nanopowders for lithium-ion storage are also investigated. The first step of post-treatment of the spray-dried powders under a reducing atmosphere forms spherical and hollow NaCl powders embedded with Cu nanocrystals. Further post-treatment of the Cu–NaCl composite powders under an air atmosphere forms the spherical and hollow NaCl powders embedded with the hollow CuO nanopowders. Oxidation of the Cu nanocrystals under an air atmosphere produces hollow CuO nanopowders by nanoscale Kirkendall diffusion. The spherical and hollow CuO–NaCl composite powder transforms into ultrafine hollow CuO nanopowders by complete washing with distilled water to remove NaCl. The initial discharge and charge capacities of the hollow CuO nanopowders for lithium-ion storage at a current density of 1 A g−1 are 1077 and 781 mA h g−1, respectively. The reversible discharge capacity of the hollow CuO nanopowders for the 700th cycle is 803 mA h g−1.

Electrochemical properties of CuO hollow nanopowders prepared from formless Cu–C composite via nanoscale Kirkendall diffusion process

Hollow CuO nanopowders are prepared using a simple spray drying process that relied on nanoscale Kirkendall diffusion; these nanopowders have potential applications in lithium-ion batteries. Citric acid is used as both the carbon source material and chelating agent and plays a key role in the preparation of the hollow nanopowders. The formless Cu–C composite that formed as an intermediate product transforms into slightly aggregated CuO hollow nanopowders after post-treatment at 300 and 400 °C under an air atmosphere. The CuO hollow nanopowders exhibit higher initial discharge capacities and better cycling performances than those of the filled-structured CuO nanopowders, which are prepared at a post-treatment temperature of 500 °C under an air atmosphere. The discharge capacities of the CuO nanopowders post-treated at 300, 400, and 500 °C for the 150th cycle at a current density of 1 A g−1 are 793, 632, and 464 mA h g−1, respectively, and their capacity retentions calculated from the maximum discharge capacities are 88, 80, and 73%, respectively. The CuO nanopowders with hollow structures exhibit better structural stability for repeated lithium insertion and desertion processes than those with filled structures.

An investigation on the tuning effect of glucose-capping on the size and bandgap of CuO nanoparticles

We report herein the synthesis of CuO nanoparticles with varying concentrations of the organic modifier glucose as capping agent by the facile and versatile sol–gel route. The microstructure, surface morphology with composition, optical and transport properties of the nanoparticles thus produced were analyzed using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Electron Diffraction X-ray Analysis (EDAX), Fourier Transform Infrared Spectroscopy (FTIR), UV–Visible Spectroscopy (UV–Vis) and photoconductivity techniques. XRD analysis showed that the crystallite size of the nanoparticles as calculated by the Scherrer’s formula tends to decrease with increase in the molar concentration of capping agent. SEM results revealed that with increase in the molar concentration of the capping agent CuO nanopowder tends to become more homogeneous and thus well prevented the agglomeration of the nanoparticles. Also the particle size was observed to decline with increasing capping agent concentration. Band gap calculations made employing the Tauc’s plot method indicate a consistent increase in the band gap with increase in concentration of capping agent corresponding to the reduction in particle size. The impact of the capping agent on the vibration pattern of CuO nanoparticles is evident from the FTIR spectra. The photoconductivity of the CuO nanoparticles showed a decrease in the dark and photo current values with the increase in molar concentration of the capping agent which could be attributed to the increase in the optical band gap. Thus the particle size and hence the band gap of nanoparticles could be tuned effectively by altering the concentration of the capping agent.

Selective removals of heavy metals (Pb2+, Cu2+, and Cd2+) from wastewater by gelation with alginate for effective metal recovery

A novel method that uses the aqueous sodium alginate solution for direct gelation with metal ions is developed for effective removal and recovery of heavy metals from industrial wastewater. The experimental study was conducted on Pb2+, Cu2+, and Cd2+ as the model heavy metals. The results show that gels can be formed rapidly between the metals and alginate in less than 10min and the gelation rates fit well with the pseudo second-order kinetic model. The optimum dosing ratio of alginate to the metal ions was found to be between 2:1 and 3:1 for removing Pb2+ and around 4:1 for removing Cu2+ and Cd2+ from wastewater, and the metal removal efficiency by gelation increased as the solution pH increased. Alginate exhibited a higher gelation affinity toward Pb2+ than Cu2+ and Cd2+, which allowed a selective removal of Pb2+ from the wastewater in the presence of Cu2+ and Cd2+ ions. Chemical analysis of the gels suggests that the gelation mainly occurred between the metal ions and the COO− and OH groups on alginate. By simple calcination of the metal-laden gels at 700°C for 1h, the heavy metals can be well recovered as valuable resources. The metals obtained after the thermal treatment are in the form of PbO, CuO, and CdO nanopowders with crystal sizes of around 150, 50, and 100nm, respectively.

Structure, optical and magnetic behavior of nanocrystalline CuO nanopowders synthesized via a new technique using Schiff base complex

New Cu(II) Schiff base complex [Cu(L)(H2O)Cl] have been synthesized using the sonochemical route. Then, nanocrystaline monoclinic copper oxide CuO phase were obtained from the complex by annealing the formed Cu(II) Schiff base complex at 600 °C for 2 h. The crystallite size of the formed CuO was 51.5 nm. The formed CuO sample was appeared as cubic-like structure. Besides, the band gap energy of the CuO nanoparticles was 1.39 eV. Meanwhile, the photoluminescence emission spectra measurement (PL) at different excitation bands were evinced that CuO exhibited luminescence band around at 403 nm. Indeed, the saturation magnetization (Ms) was 0.17 μ/g whereas the coercivity (Hc) was 233.5 Oe, indicating the weak ferromagnetic behavior of the formed CuO powders was observed. Consequently, in this paper we illustrates that the organic–inorganic compounds may be suitable precursors for synthesis of nano-scale materials. The sonochemistry method may have some advantages such as: it takes place with shorter reaction times and produces better yield.

Low-temperature catalytic CO oxidation over mixed silver–copper oxide Ag2Cu2O3

Mixed silver–copper oxide Ag2Cu2O3 was investigated by a combination of physicochemical techniques, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and temperature programmed reaction (TPR). The catalytic properties of Ag2Cu2O3 in the reaction of CO oxidation were studied by the TPR-CO+O2 method and compared with those of CuO nanopowder characterized by a similar specific surface area. On the surface of Ag2Cu2O3, two unequivalent oxygen species (Eb(O1s)=529.4eV and 531eV) with different reaction probability towards CO were observed. Previously, similar oxygen species had been found on the surface of CuO nanopowder. Mixed silver–copper oxide interacted with CO at room temperature, which resulted in the surface reduction Cu2+→Cu1+. Such reduction was accompanied by the removal of only oxygen with Eb(O1s)∼531eV. When the mixed oxide was heated in the reaction medium, both oxygen species were eliminated from the surface, leading to the partial decomposition of the Ag2Cu2O3 structure and the appearance of metallic silver. The TPR-CO study showed the presence of weakly bound oxygen species which can be adsorbed on oxygen vacancies in the Ag2Cu2O3 paramelaconite structure. The energy of oxygen vacancy formation on the (001) and (101) surfaces of Ag2Cu2O3 were calculated by periodic density functional theory (DFT). The role of different oxygen species in CO oxidation over the Ag2Cu2O3 surface is discussed.

Synthesis of CuO nanopowders by high-energy ball-milling method and investigation of their catalytic activity on thermal decomposition of ammonium perchlorate particles

In this research, nearly spherical CuO nanopowders (NPs) were synthesized in a high-energy ball-milling method at room temperature for different milling times (20 and 40 h) at dry medium. The structure, particle size, purity and morphology of the resulting CuO NPs were characterized by X-ray diffraction, inductively coupled plasma and scanning electron microscopy (SEM) techniques. The results showed that the NPs obtained after 40 h have the smallest particle with only 31 nm. These NPs were studied as an additive for promoting the thermal decomposition of ammonium perchlorate (AP) particles. The photographs of field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy showed that the surface of CuO NPs was successfully coated with AP particles. Also, differential scanning calorimetry (DSC) and thermogravimetry analysis (TG) techniques were used to investigate the thermal decomposition of pure and AP + CuO nanocomposites. The DSC/TG results showed that CuO NPs with 31 nm had an excellent catalytic effect on the AP thermal decomposition property and by adding 2 and 5 % additive, decomposition temperatures decreased by 81.9 and 90.4 °C, and the heat of decomposition increased by 707.6 and 839.9 J g−1, respectively. Finally, the apparent activation energy (E), ΔG #, ΔH #, ΔS # of thermal decomposition processes of pure and treated samples were obtained by non-isothermal methods proposed by Kissinger and Ozawa.

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).

Effect Of Synthesis Time On Structural, Optical And Electrical Properties Of CuO Nanoparticles Synthesized By reflux Condensation Method

CuO nanopowder oxide was synthesized by reflux condensation method without any surfactants or templates, using copper nitrate in deionized water and aqueous ammonia solution. The structural, optical and electrical properties of the sample were investigated using X-ray diffraction (XRD), FT-IR, UV-visible spectroscopy and impedance spectroscopy measurements. The X-ray diffraction patterns revealed that CuO nanoparticles (NPs) was formed in pure monoclinic phase and good crystalline quality, whose NPs sizes were of the order 25 nm which an average size can be tailored by the synthesis time. FT-IR spectra of CuO NPs used to detect the possible adsorbed species on the CuO materials. In addition, the peaks at 529 and 604 cm -1

Superior electrochemical performances of double-shelled CuO yolk–shell powders formed from spherical copper nitrate–polyvinylpyrrolidone composite powders

Spherical copper nitrate–polyvinylpyrrolidone (PVP) composite powders coated with a copper nitrate hydroxide [Cu2(OH)3NO3]–carbon composite are prepared by a one-pot spray pyrolysis process. In this, Cu2(OH)3NO3 and carbon are formed by dehydration of copper nitrate and carbonization of PVP, respectively. Thermal decomposition of the composite powders is then performed at 300 °C under an air atmosphere, producing the final yolk–shell-structured CuO powders. The electrochemical properties of these powders are then compared with those of commercial CuO nanopowders. The discharge capacities of the CuO yolk–shell powders and the commercial CuO nanopowders after 240 cycles at a current density of 500 mA g−1 are 590 and 302 mA h g−1, respectively. Furthermore, the discharge capacity of the CuO yolk–shell powders is as high as 615 mA h g−1, even after 1000 cycles at a current density of 1000 mA g−1. Electrochemical impedance spectroscopy reveals that the structural stability of the CuO yolk–shell powders during cycling lowers the charge transfer resistance, and thereby improves the lithium ion diffusion rate.

Facile synthesis and characterization of tenorite nanoparticles from gas-atomized Cu powder

CuO powder is widely used because of its high activity and selectivity in oxidation/reduction reactions. CuO nanoparticles are interesting because of their high ratio of surface area to mass, which is expected to enhance the catalytic performance of a material. Because of such importance, CuO nanoparticles were prepared by two different facile routes. The first involved the reaction of pure Cu powder with nitric acid to form Cu(NO3)2 intermediate. In the second route, glacial acetic acid was employed to react with pure Cu powder to form Cu(CH3COO)2 intermediate. After purification, both intermediates were reacted with NaOH via a solid-state route to form CuO powders. The intermediates and end products were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray diffraction technique. Experimental results indicated that synthesis of the CuO nanoparticles via the Cu(NO3)2 intermediate yielded slightly higher product and fine particle sizes with a larger aspect ratio. In contrast, the Cu(CH3COO)2 intermediate route yielded lower product yield and fine particle sizes with a smaller aspect ratio. However, due to the extremely fine particle size it was observed that nanoparticle agglomeration could not be avoided particularly in the CuO nanopowders produced via the Cu(CH3COO)2 intermediate route.

Synthesis and investigation of stable copper nanoparticle colloids

The synthesis of stable nanoparticle colloids by laser ablation of the copper target in water and fragmentation of Cu + CuO nanopowder with pulsed fiber laser irradiation with a wavelength of 1064 nm and pulse duration of 100 ns has been investigated experimentally. The influence of the technological parameters on the nanoparticle size and stability of the colloid has been studied. It has been shown that the laser ablation creates the CuO spherical nanoparticles. Subsequent fragmentation makes it possible to reduce the nanoparticle size in a colloid and to produce a stable colloidal solution from an aqueous suspension of Cu + CuO nanopowder.

Optical and structural properties of tenorite nanopowders doped by Si and Zr

In this study preparation of Si and Zr doped CuO nanopowders have been investigated. The effects of Si and Zr doping and heat treatment temperature on the structural and optical properties of Nanopowders have been studied by X-ray diffraction (XRD), Scanning electron microscopy (SEM-EDX), UV-Vis absorption and FTIR spectroscopy. Nanopowders were obtained by sol gel method under room conditions (temperature, 25–32 $$^{\circ }\mathrm{C}$$ ) and were subsequently calcined at different temperatures (400–700 $$^{\circ }\mathrm{C}$$ ). XRD results suggest that adding impurities has a significant effect on the crystallinity, and particle size of CuO. The patterns showed that CuO nanopowders calcined at different temperature were Tenorite structure. The optical absorption spectrum indicates that the CuO nanoparticles have a direct band gap of 1.78 eV. But optical band gap of the doped CuO (15 % Si and 15 % Zr) was found to be 3.75–3.95 eV.