Nano-sized Copper Research Articles

Synthesis and characterization of nanosize copper oxide by non-aqueous sol–gel process

Synthesis and characterization of nanosize copper oxide by non-aqueous sol–gel process

Fabrication of CuO/Au Nanowires on a Copper Substrate for Ultra-Sensitive SERS Sensors

To optimize the surface-enhanced Raman (SERS) phenomenon on the surface of noble metals, gold nanoparticles were synthesized on the surface of nano-sized copper wires to enhance the dispersion of gold particles on the research surface. A simple experimental procedure was carried out in two stages. First, the thin copper substrate was lightly oxidized with ammonium persulfate in an alkaline environment, then incubated at 200oC for 3 hours to form copper nanowires that exist stably on the substrate surface. Immediately afterward, highly uniform CuO/Au nanowires were formed by the chemical reduction of HAuCl4 on the surface of the oxidized copper plate. The results show that gold nanoparticles of about 5 nm were attached to CuO nanowires with a length of up to 10 µm and a diameter between 100 and 300 nm. The X-ray energy dispersive spectrum demonstrated a uniform distribution of gold particles. The CuO/Au structure was used as a SERS substrate to detect methylene blue at a low concentration of 10 pM corresponding to 2 signals at the peaks 1395 cm−1 and 1625 cm−1 as the C-H and C-C deformation vibrations of the aromatic ring. The logarithms of the methylene blue concentrations were linearly proportional to their SERS signal intensity of methylene blue at the peak of 1625 cm-1 with a value R2 = 0.96. The signals of SERS for methylene blue at twelve different points on the material sample showed no significant differences in both intensity and shape of the spectrum, with an RSD value of 5.9%.

An antibacterial membrane based on Janus bacterial cellulose with nano-sized copper oxide through polydopamine conjugation for infectious wound healing

Bacterial cellulose (BC) produced by Acetobacter xylinum has great advantages in wound dressing. However, the structural limitation under static culture, and lack of antibacterial properties restrict its application, especially for infectious wound healing. The present study reported an original wound dressing, which was composed of a Janus BC membrane with antibacterial nano-sized copper oxide (CuO) through polydopamine (PDA) conjugation to promote wound healing under infectious condition. The finished product (CuO/PDA/BC membrane) exhibited favorable air permeability, high hydrophilicity and good mechanical properties, as well as strong antibacterial effects by the sustained release of CuO and photothermal effect of CuO/PDA. Furthermore, CuO/PDA/BC membrane inhibited inflammatory response and promoted wound healing in an infectious wound model in vivo. These results suggested that our CuO/PDA/BC membrane had great potential as wound dressing for infectious wound healing.

Investigating the catalytic effect of nanoferrites additives on the thermal decomposition of ammonium perchlorate and burning rate modification of the composite solid propellants

The co-precipitation method was used to synthesize nanosize copper ferrite (CuF) and cobalt-copper-nickel ferrite (CoCuNiF). Physico-chemical characterization of material was done using powder X-ray diffraction, Raman, UV–Vis, and atomic force microscopy (AFM). The effect of 1 % by mass additives on the thermal decomposition and kinetics parameters of ammonium perchlorate (AP) was investigated using non-isothermal isoconversional methods such as Flynn wall Ozawa (FWO), Kissinger Akahira Sunose (KAS), and Starink. The burning rate enhancement and ignition delay study were also investigated. The catalysts can decrease the activation energy of AP by 48 % along with increasing the burning rate of the corresponding composite materials. Both the catalysts can be successfully used for enhancing the burning performance of propellants and hence can be used for rocket and missile propulsions.

Hydrolysis of polyacrylamide in the presence of nano-sized copper particles

The process of hydrolysis of amide groups of polyacrylamide in the presence of a dispersion of nanosized copper particles obtained by the reduction of copper cations with sodium tetraborate was studied. Quantum chemical calculations showed an increase in the effective positive charge on the carbon atom in the amide group upon formation of a complex with copper. Calculation of the energy of interaction of polyacrylamide and polyacrylic acid macromolecule units with copper particles showed the possibility of replacing amide groups of the polymer that underwent hydrolysis from the surface of copper particles with amide groups that did not participate in the reaction. The degree of hydrolysis of polyacrylamide in the presence of copper particles was 89%, and in the absence of particles 22%.

Nano-sized copper particles: Chemical synthesis, characterization, and their size and surface charge dependent antibacterial potential

Copper nanoparticles (Cu NPs) were studied extensively for their antibacterial potential compared to other metal NPs in the recent past. However, comparative analysis of different reducing and stabilizing agents in the synthesis of Cu NPs and their possible effect in antibacterial activity is not clearly stated. Herein, authors report the synthesis of Cu NPs using three reducing and stabilizing agents such as sodium borohydride (SBH), tri-sodium citrate (TSC), and oxalic acid (OA), individually. The as-synthesized Cu NPs were studied for their optical, physicochemical, and morphological properties followed by their role (shape and surface charge of NPs) in defining its antibacterial potential. Cu NPs@SBH showed moderate to good antibacterial activity against Escherichia coli (15.23 ± 0.65 mm), Lactococcus lactis (20.65 ± 0.96 mm), Micrococcus luteus (21.48 ± 1.12 mm), Bacillus sp. (14.33 ± 0.52 mm), and Pseudomonas putida (19.58 ± 0.43 mm). Cu NPs@SBH had average particle size of 46.8 nm and surface charge of −42.1 mV. The results indicate that both size and surface charge played a vital role in the antibacterial activity of Cu NPs.

Hydrolysis of Polyacrylamide in the Presence of Nano-Sized Copper Particles

Hydrolysis of Polyacrylamide in the Presence of Nano-Sized Copper Particles

Nano-Sized Copper Films Prepared by Magnetron Sputtering

Nano-Sized Copper Films Prepared by Magnetron Sputtering

Biological effects of exposure to copper nanoparticles: markers of exposure

Introduction. Aerosol nanoparticles at operating metallurgical plants are potent of the significant risk factor that needs to be studied.
 The purpose of the work was to study biological effects of exposure to copper nanoparticles compared to microparticles and identify potential markers of the exposure.
 Materials and methods. Two experimental groups of rats, twelve animals each, were subchronically exposed to copper-containing nanoparticles and microparticles injected intraperitoneally. Changes in their biochemical parameters, tissues, and organs were then compared to those in the control rats administered with deionized water. During periodic medical examinations of workers occupationally exposed to copper-containing aerosols with different particle size distribution, additional laboratory and instrumental methods of testing were used to identify possible exposure effects to health manifested by changes in biochemical parameters.
 Results. The experimental study showed that in liver, the exposure to copper nanoparticles, compared to microparticles, induced a more significant inhibition of replication of hepatocytes in regeneration, as demonstrated by the number of binuclear cells, and an increase in the number of Kupffer cells (tissue macrophages), while in kidney, it caused a more pronounced convoluted tubule brush border loss. The exposure to both micro- and nano-sized copper particles was found to induce pathological changes in neurons of the ganglionic layer of the cortex and basal nuclei. Test results showed a significant increase in the blood concentration of ceruloplasmin in the core personnel of the metallurgical plant following the exposure to copper aerosols rich in nanoparticles.
 Limitations. The assessment of the results of the impact of copper nanoparticles in the composition of the aerosol on the health of 224 employees of the enterprise and the results of the experiment obtained on 36 animals corresponded to the current social and ethical standards and norms.
 Conclusion. Specifics of the exposure to nanoparticles require a revision of approaches to regulating aerosols with account for particle size distribution.

Application of physical vapor deposition technology for practical utilization of nano-size copper oxide for lead uptake from solution: kinetics, equilibrium, and recycling studies

For the first time, copper oxide-coated glass beads (CuO-GBs) were fabricated using physical vapor deposition (PVD) technology for sequestrating Pb2+ ions from solution is addressed. Compared to other coating procedures, PVD offered high-stability uniform CuO nano-layers attached with 3.0-mm glass beads. Heating of copper oxide-coated glass beads after deposition was rather necessary to achieve the best stability of the nano-adsorbent. Detection of nano-size copper oxide on the beads was made by FTIR (intense peak at 655cm-1 for CuO bond stretching) and XRF (Cu peak at 8.0keV). Scanning electron micrographs taken at high magnification power indicated the presence of CuO in nano-range deposited over glass beads. The maximum deposited amount of CuO on the beads was 1.1% and accomplished at the following operational conditions: internal pressure 10-5mmHg, Ar flow rate 8.0mL/min, voltage 84V, pre-sputtering time 20s, total sputtering time 10.0min, and post-heating temperature 150°C for 3h. A univariate analysis indicated that the optimum Pb2+ uptake by CuO-GBs from solution was achieved at pH 7.0-8.0, 7 beads/50mL, 120-min contact time, and 15-mg/L initial concentration. Kinetic data for Pb2+ uptake was best presented by a pseudo-second-order model with a relative prediction error of 3.2 and 5.1% for GBs and CuO-GBs, respectively. On the other hand, Pb2+ equilibrium isotherms at 25°C were fairly presented by the Langmuir model, and the predicted saturation values were 5.48 and 15.69mg/g for GBs and CuO-GBs, respectively. CuO and CuO-GBs had similar Pb2+ saturation values (~ 16mg/g), although the latter demonstrated 4 times faster kinetic, thanks to fixation CuO on glass beads. Moreover, the chemical stability of copper oxide-coated glass beads was tested under different conditions. Recycling of copper oxide-coated glass beads was also investigated, and 90% of the surface was recovered using 0.01-M HNO3.

An inverse nano-cavity/-inhomogeneity problem with surface/interface effects in terahertz frequency range

In nondestructive evaluation, the maximum wavelength of the incident wave must be smaller than twice the perceptible obstacle size. Hence, in order to be able to detect a nanosize fiber of radius about a few nanometer, the frequency of the incident elastic wave should be in the order of 1012 Hz, i.e., in the terahertz frequency range. The present work addresses the possibility of application of elastic waves in terahertz frequency range to detect embedded circular nanosize inhomogeneity or nanocavity for which, respectively, the interface and surface effects are remarkable. Traditionally, singular sources method (SSM) and linear sampling method (LSM) have been utilized to treat inverse problems in the context of classical elasticity theory, where the surface/interface effects are not important. In the present paper these methods are extended to operate in the mathematical framework of surface/interface elasticity theory, suitable for capturing the surface/interface effects. In this framework the boundary conditions in contrast to the common Dirichlet and Neumann types involve the second derivative of the displacement field. The validity and uniqueness of the extended LSM and SSM in this framework will be established. An exact analysis emphasizing the importance of the consideration of surface/interface effects will also be given for the direct problem of SH waves scattering. In this work, the scatterer will be reconstructed solely based on data from the incident waves and the far-field pattern. Using the proposed theory, the size and location of the embedded nano-size cavity and nano-size inhomogeneity are detected. The surface effects of a nano-size cavity within a silver plate are more significant than the copper–silver interface effects in the case of a nano-size copper inhomogeneity embedded in a silver plate.

Cu/SiO2 CATALYSTS OBTAINED BY CATIONIC ADSORPTION FROM DIFFERENT PRECURSOR SALTS

In this work the effect of different copper precursor salts (acetate, nitrate, sulfate) on the physicochemical characteristics of Cu/SiO2 catalysts is studied. The catalysts were prepared by the cationic adsorption method and analyzed by several characterization techniques (TGA, DSC, FTIR, XRD, AAS, SEM-EDS, N2-sorptometry and TPR). The results showed that the copper acetate precursor generated highly dispersed nano-sized copper oxide species on the silica surface, while the copper nitrate precursor leaded to bulk-type copper oxide strongly interacting with the silica, and the copper sulfate precursor did not decompose completely during the catalyst preparation. Besides, the acetate precursor produced the highest copper content, due to lower acidity of its solution, which generated a higher density of negative charge on the silica surface and a higher affinity for cupric ions. In conclusion, the great influence of the nature of the precursor salt on the physicochemical characteristics of silica-supported copper catalysts is established.

Synthesis, Characterization and Environmental Application of Copper Oxide Nanoparticle obtained Using Aqueous Extract of Schrebera Swietenioides Roxb.

The goal of the present study was to synthesize the nanoparticles using green methodology with the use of the aqueous plant extract of S. swietenioides. The copper oxide nanoparticle has been synthesized using aqueous root extract of S. swietenioides as a green reducing agent and copper sulfate as source of the metal ions. Formation of the nanoparticles in the reaction mixture was preliminary confirmed by the UV-Vis spectroscopy method. The FT-IR analysis of the synthesized nanoparticles shows the involvement of various bioactive functional groups in the formation of nanoparticles. The UV–Vis absorption spectra indicate the characteristic maximum absorption peak at a wavelength of 340 nm. This confirms the formation of nano-sized copper particles. The SEM analysis of the synthesized copper oxide nanoparticles confirms that the particles have mostly spherical shape with rough surfaces and the size of 21-43 nm. The copper nanoparticles in the media of the aqueous root extract of S swietenioides have been studied for their applications in the photo catalytic reduction of pollutant dyes and metals. The synthesized nanoparticles have been characterized and it was proved that the particles were nano-sized and contained high metal percentage.

Degradation of Orange G in water by nano-Cu0/H2O2 process with nano-Cu0 synthesized in a rotating packed bed with blade packings

In this investigation, Orange G in water was degraded by the nano-Cu0/H2O2 process with nano-sized copper particles (RPB-nano-Cu0) that were synthesized by chemical reduction in a rotating packed bed (RPB) with blade packings. The effects of H2O2 dosage and RPB-nano-Cu0 dose on the degradation of Orange G by the RPB-nano-Cu0/H2O2 process were investigated. An optimal H2O2 dosage in the degradation of Orange G by the RPB-nano-Cu0/H2O2 process was 5 mmol/L for a RPB-nano-Cu0 dose of 0.25 g/L. An optimal RPB-nano-Cu0 dose in the degradation of Orange G by the RPB-nano-Cu0/H2O2 process was 0.25 g/L for an H2O2 dosage of 5 mmol/L. The RPB-nano-Cu0/H2O2 process with 25 °C, pH 3, an H2O2 dosage of 5 mmol/L, and a RPB-nano-Cu0 dose of 0.25 g/L exhibited an efficiency of degradation of Orange G (10 mg/L) of 93% at 30 min. The efficiency of degradation of Orange G (10 mg/L) using commercial nano-Cu0 from Sigma-Aldrich (0.25 g/L) in the presence of H2O2 (5 mmol/L) at pH 3 was 73% after 30 min. The RPB-nano-Cu0/H2O2 process exhibited the great potential in the efficient degradation of Orange G in water.

Effect of Thermal Treatment on Nano- and Micro-Copper Particles for Jewelry Making

Copper nanoparticles are being applied in the biosensors, engineering, electronic devices, and technology fields. A key advantage of nanomaterials is that their properties differ from their bulk with the same composition. However, the application of nano-copper particles for jewelry and artwork has not yet been revealed. We discovered and compared the application of nano-sized copper particles in jewelry fabrication with micro-copper particles. The nano- and micro-sized copper particles were synthesized and mixed with the same organic binders and water content to produce an alternative clay-like material for creating handmade jewelry and artwork. The article addresses the effects of thermal treatment on thermal behavior and the development of physical properties of differently sized copper particles. Their physical properties depend strongly on the size of the starting copper particles and heating conditions. We investigated the influence of thermal treatment, heating rate, firing temperature, and holding time to optimize the firing conditions for jewelry fabrication and wearing.

Effect of Micro Nano-Structured Copper Additives with Different Morphology on Tribological Properties and Conductivity of Lithium Grease

ABSTRACT In order to explore the effect of micro nano-structured copper additives with different morphology on tribological properties and conductivity of lithium base grease, nano-sized copper sheets (denoted as Cu NSs), micro-sized copper wires (denoted as Cu MWs) and copper particles (denoted as Cu Ps) between micrometer and nanometer scale were prepared by liquid-phase chemical methods. The effects of synthetic variables such as reaction temperature, reaction time and pH value of reactant solution on the morphology of the final products were investigated. The as-prepared Cu NSs, Cu MWs, and Cu Ps were characterized by field emission scanning electron microscopy and X-ray diffraction. Their effects on the tribological properties and conductivity of lithium grease were investigated via ball-on-disk sliding tests and contact resistance measurements as well as morphology and element composition analyses of worn block surface. The experimental results show that the morphology of the product is significantly affected by the experimental conditions. This makes it feasible to fabricate copper additives with desired morphology by properly tuning the reaction conditions. Besides, the as-prepared copper additives can improve the tribological properties and conductivity of lithium base grease, because they can be adhered and deposited on rubbed steel surfaces to form boundary lubricating films consisting of cuprous oxide, cupric oxide, ferric oxide and other oxides.

Synthesis of Multiscale Ultrafine Copper Powder via Radio Frequency Induction Coupled Plasma Treatment

Nano-sized spherical copper powder has important applications in the fields of microelectronic devices, highly efficient catalysts and lubricant additives. In this study, nano-sized and micron-sized spherical copper powders were simultaneously prepared by radio frequency (RF) induction coupled plasma technology. The effects of processing parameters on the powder properties were studied. The results show that by inputting copper powder with D50 = 34.6 μm, nano-sized spherical powder with a particle size of 10–220 nm and micron-sized spherical powder with a particle size of 4.0–144.0 μm were obtained. The ratio of the nano-sized powder reached 86.4 wt.%. The optimal processing parameters are as follows: powder feed rate is 5.5 g/min, carrier gas flow rate is 5–6 L/min and reaction chamber pressure is 15 Psia. When the carrier gas flow rate is 6 L/min, in the plasma zone (>10,000 K), the powder with particle size <42.0 μm is completely vaporized, which forms nano-sized powder during cooling, while the powder with particle size >42.0 μm is melted and partially vaporized, forming a micron-sized powder. The research results provide a new way for engineering the production of copper nano-powder and some other nano-powders with low melting points, such as silver powder, tin powder and so on.

Enhanced Methanol Production over Non-promoted Cu–MgO–Al2O3 Materials with Ex-solved 2 nm Cu Particles: Insights from an Operando Spectroscopic Study

Enhanced methanol production is obtained over a non-promoted Cu–MgO–Al2O3 mixed oxide catalyst derived from a Cu–Mg–Al hydrotalcite precursor (HT) containing narrowly distributed small Cu NPs (2 nm). Conversions close to the equilibrium (∼20%) with a methanol selectivity of 67% are achieved at 230 °C, 20 bar, and a space velocity of 571 mL·gcat–1·h–1. Based on operando spectroscopic studies, the striking activity of this Cu-based catalyst is ascribed to the stabilization of Cu+ ions favored under reaction conditions due to lattice reorganization associated with the “HT-memory effect” promoted by water. Temperature-resolved infrared–mass spectrometry experiments have enabled the discernment of monodentate formate species, stabilized on Cu+ as the intermediate in methanol synthesis, in line with the results of density functional theory calculations. These monodentate formate species are much more reactive than bridge formate species, the latter ones behaving as intermediates in methane and CO formation. Moreover, poisoning of the Cu0 surface by strongly adsorbed species behaving as spectators is observed under reaction conditions. This work presents a detailed spectroscopic study highlighting the influence of the reaction pressure on the stabilization of active surface sites, and the possibility of enhancing methanol production on usually less active non-promoted nano-sized copper catalysts, provided that the proper support is selected, allowing the stabilization of doped Cu+. Thus, a methanol formation rate of 2.6 × 10–3 molMeOH·gcat–1·h–1 at 230 °C, 20 bar, and WHSV = 28 500 mL·gcat–1·h–1 is obtained on the Cu–MgO–Al2O3 HT-derived catalyst with 71% methanol selectivity, compared to 2.2 × 10–4 molMeOH·gcat–1·h–1 with 54% methanol selectivity obtained on a reference Cu/(Al2O3/MgO) catalyst not derived from a HT structure.

Biocompatibility and antimicrobial activity of copper(II) oxide hybridized with nano silicate platelets

Nano-sized copper(II) oxide (CuO) is an interesting material with proficient antibacterial activities but limited due to its toxicity to mammalian cells. In this study, CuO nano-sized needles were coated on the surface of nano-silicate platelets (NSP), which were exfoliated from natural montmorillonite clays and with the thickness of about 1 nm, to form nanohybrids. Our findings indicate that NSPs can effectively prevent the aggregation of CuO needles, and significantly enhance antibacterial efficiency without affecting biocompatibility. An optimal antibacterial activity against Staphylococcus aureus exceeding 99% could be obtained, while that for Escherichia coli was about 88%. Electron paramagnetic resonance results suggest that •OH radicals, one of the reactive oxygen species generated by CuO/NSP, might damage the cellular components and thus result in the death of bacterial.

Nano-sized copper oxide enhancing the combustion of aluminum/kerosene-based nanofluid fuel droplets

The use of nano-sized copper oxide (nCuO) in Al-based nanofluid fuels was presented as a way to improve the combustion of traditional aluminum (Al)-based nanofluid fuels. The effects of nCuO on the ignition delay time, ignition temperature, droplet behavior, burning rate, and combustion intensity of Al/kerosene-based nanofluid fuel droplets were investigated. The results reveal that adding 2 wt% nCuO to the 2 wt% Al/kerosene-based nanofluid fuel has little effect on the ignition delay time and ignition temperature at 700, 750, and 800 °C. However, the droplet diameter changes dramatically with time at 750 and 800 °C. The burning rate is enhanced by up to 21.7%, and the combustion intensity and the oxidation efficiency of Al nanoparticles (NPs) are also improved significantly. This study provides an effective approach to improve the combustion performance of Al/kerosene-based nanofluid fuels.