CuO Micro Research Articles

Efficient lock-in CuO/WON heterostructures tailored for highly sensitive electrochemical detection of hazardous herbicide diuron in fruit juices and aqua region

A micro-nano lock-in heterostructure has attracted significant attention for electrochemical sensor application due to its high specific surface area, more exposed active sites, and fast ion transport. Despite these advantages, here we prepared lock-in hetero structured tungsten oxynitride (WON) with a flower of CuO architecture by using the impregnation method. The tungsten oxynitride (WON) was prepared from the doping of nitrogen over the lattice of WO3 via a reactive NH3 gas etching process which turns WO3 nanoflakes (NFs) into the WON etched nanoflakes (EFs). The EFs act as cages to hold the hydrothermally prepared CuO micro flowers (MFs) and forms a new type of ‘lock-in’ heterostructure. This structure enables the stable and faster charge transfer between the CuO MFs and WON EFs, resulting in an efficient electrochemical performance towards the detection of diuron herbicide. The prepared CuO/WON were subjected to physiochemical characterizations such as X-ray diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The morphological and elemental information was interpreted by field-emission scanning electron microscopy (FESEM) combined with EDX and mapping analysis. Then, CuO/WON/GCE sensor electrode exhibited a wide diuron (DU) detection range of about 0.01–764.4 µM. Moreover, the estimated limit of detection and sensitivity from the slope of DU detection is 5.5 nm and 0.445 µM µA−1 cm−2 respectively. The practical applicability of the sensor electrodes was tested in the DU-added grape juice, orange juice, tap water, and river water samples.

Facile Synthesis of 3D Sea Urchin-like CuO Microspheres Structures and its Higher Photocatalytic Properties

The three-dimensional (3D) sea urchin-like CuO microspheres structures were successfully synthesized by a simple hydrothermal method. With the hydrothermal temperature increases, the morphology of CuO micro-/nanostructures has changed: When the hydrothermal temperature reaches above 40 °C, the irregular CuO particles transform into a 3D sea urchin-like CuO microspheres. X-ray diffraction spectrum and Raman scatting spectra confirm that the obtained 3D sea urchin-like CuO microspheres at hydrothermal temperature of 60 °C are composed of a high purity and single-phase monoclinic CuO. It is found that the 3D sea urchin-like CuO microspheres structures exhibit the better photocatalytic property for degradation of methylene blue (MB) solution under the visible light irradiation compared to the irregular CuO particles, which duo to the relatively larger specific surface area of the sea urchin-like CuO microspheres structures, exposing more active sites and increasing the contact area between the catalyst and dye molecule. This remarkable photocatalytic performance of the 3D sea urchin-like CuO microspheres structures might has a promising application in waste water treatment.

Mathematical Prospective of Latent Heat Storage System with CuO Micro Particle Enhancement

Mathematical Prospective of Latent Heat Storage System with CuO Micro Particle Enhancement

Synthesis of CuO micro and nanoparticles as composite additives for corrosion resistant Zn-composite coatings on mild steel

Micro and nano structured CuO particles were synthesized from co-precipitation method. The average crystallite size and morphology of the particles were determined using X-ray diffraction and scanning electron microscope (SEM) techniques. The effects of micro and nano sized CuO particles on the corrosion resistance of a Zn-coating were studied. The Zn-composite coatings were developed by electrodeposition using a Zn-sulfate plating bath suspended with micro/nano structured CuO particles under dc conditions. The co-deposition of secondary phase particles in the Zn-metal matrix changed the surface morphology of the metal matrix which has been analyzed by SEM photo micrographs. The Tafel and electrochemical impedance spectroscopy (EIS) corrosion tests were performed to study the corrosion resistance property of the coatings. The corrosion resistivity of Zn-metal matrix was more improvised by the co-deposition of CuO nanoparticles than by the CuO microparticles.

Hydrogen peroxide-assisted synthesis of novel three-dimensional octagonal-like CuO nanostructures with enhanced visible-light-driven photocatalytic activity

Novel three-dimensional octagonal-like CuO micro-/nanostructures with diameters ranging from 10 to 15 μm have been successfully prepared by hydrogen peroxide-assisted hydrothermal method and subsequent calcination. The product morphology can be changed by simply ordering the amount of hydrogen peroxide (H2O2). When the amounts of H2O2 is increased, the length of the corner portion is increased and the width is narrower. The obtained octagonal CuO nanostructures were evaluated for their ability for the degradation of hazardous organic contaminants in water under visible-light irradiation. Comparing with commercial CuO and other CuO products, the CuO octagonal nanostructures exhibit excellent performance for photocatalytic decomposition of RhB (Rhodamine B). It is well established that effective photocatalytic performance results from its unique 3D octagonal nanostructures. We believe that the present work will provide some ideas for further fabrication of other novel nanostructures and exploration of their applications.

Stability analysis of CuO suspended API GL-5 gear lubricant sol

In this work, a mineral oil based gear lubricant sol is prepared by dispersing solid phase CuO particles in commercially available API GL-5 gear lubricant as a continuous liquid medium. Multifunctional micellar CuO particles are synthesized by sol-gel method and CuO-gear lubricant sol with various concentrations are prepared by ultrasonic agitation. The suspension, chemical and thermal stability of lubricant sol are analysed in UV–visible spectroscopy, Fourier Transform Infrared Spectroscopy, Thermogravimetric Analyser (TGA), and Differential Scanning Calorimeter (DSC), respectively. The chemical structures of samples retained reflect notable chemical stability and the agglomeration of CuO micro particles is observed above 0.3wt% by the effect of interface minimization which deteriorates thermo stability. Further, transition enthalpy, melting and decomposition parameters are acquired through thermograms and discussed. These results designate that the ability of absorbing and releasing thermal energy being enhanced up to 0.3wt% and further get decreased.

Particle size tuning in scalable synthesis of anti-oxidized copper fine particles by polypeptide molecular weights

Size tuning of metallic copper fine particles is highly important for their application to conductive pastes. Uniformly sized metallic copper fine particles could be successfully obtained by a chemical reduction of CuO micro powders using hydrazine in the presence of polypeptides as the stabilizing regent. Easy tuning of their particle sizes was successfully achieved via controlling the molecular weight of polypeptides. The obtained particles were covered by polypeptide capsules which were approximately 2wt% of total mass. They are highly stable even under ambient conditions.

Synthesis of 3D architecture CuO micro balls and nano hexagons and its electrochemical capacitive behavior

CuO micro balls and nano hexagons have been synthesized by time, cost effective rapid hydrothermal and precipitation methods respectively. Physical characterization is explained through various analytical techniques. Electrochemical performance of CuO as an active material for super capacitor application in 6M KOH solution is illustrated. CuO micro balls exhibit specific capacitance of about 470Fg−1 where as CuO nano hexagons exhibit only 103Fg−1 at current density of 0.5Ag−1. The superior electrochemical performance of CuO micro balls is attributed to 3D micro structure assembled from nano sheets eventually possess more active sites as evident from larger surface area observed in BET analysis. Further, co-existence of Cu2O phase enhances the electrochemical performance by reversible redox couple CuO/Cu2O and the entrapped hydroxyl group in micro balls increases the conductivity and accelerates the electrode kinetics in alkaline medium.

GC-MS metabolomics analysis of mesenchymal stem cells treated with copper oxide nanoparticles

Human exposure to copper oxide (CuO) nanoparticles (NPs) is rapidly increasing and for this reason reliable toxicity test systems are urgently needed. Recently, the acute cytotoxicity of CuO NPs using the new toxicity test based on human bone marrow mesenchymal stem cells (hBMMSCs) has been evaluated. It was shown that CuO NPs are much more toxic when compared to CuO microparticles (MPs). Several studies associate CuO toxicity to a possible alteration of reactive oxygen species (ROS) system. Unluckily, the mechanism that causes the toxicity is still not clear. In this work, the polar metabolite pool of treated cells, at the corresponding IC50 value, for CuO micro and NPs has been studied by gas chromatography coupled to mass spectrometry (GC-MS) and multivariate statistical data analysis. By the same means, differences due to different treatments, on samples, were investigated. Results of discriminant analysis were considered with the aim of finding the relevant metabolites unique for each class. Serine, glyceric acid, and succinic acid were upregulated on samples treated with CuO microparticles, while glutamine was the only discriminant metabolite for the class of samples treated with nanoparticles.

Toxic mechanisms of copper oxide nanoparticles in epithelial kidney cells

CuO NPs have previously been reported as toxic to a range of cell cultures including kidney epithelial cells from the frog, Xenopus laevis (A6). Here we examine the molecular mechanisms affecting toxicity of Cu in different forms and particle sizes. A6 cells were exposed to ionic Cu (Cu2+) or CuO particles of three different sizes: CuO NPs of 6nm (NP6), larger Poly-dispersed CuO NPs of <100nm (Poly) and CuO Micro particles of <5μm (Micro), at 200μM, equal to 12.7mgCu/L. Poly was significantly more toxic than NP6, Micro and Cu2+ to A6 cells, causing DNA damage, decreased cell viability and levels of reduced glutathione (GSH) and eventually cell death. We show that ROS (Reactive Oxygen Species) generation plays a key role and occurs early in Poly toxicity as Poly-induced DNA damage and cell death could be mitigated by the antioxidant NAC (N-acetyl-cysteine).Here we propose a model of the sequence of events explaining Poly toxicity. Briefly, the events include: cellular uptake, most likely via endocytosis, production of ROS, which cause DNA damage that activates a signaling pathway which eventually leads to cell death, mainly via apoptosis.

Investigating on photocatalytic performance of CuO micro and nanostructures prepared by different precursors

In this paper, various morphologies of copper oxide (CuO) were synthesized from acetate, sulfate, and nitrate precursors using hydrothermal bath method. The photoluminescence spectra revealed that CuO-Ni sample contains the strongest surface defect peak which can be related to its highest active surface area. The Fourier transform infrared (FT-IR) results showed that the concentration of the surface OH− group on the samples varies considerably according to CuO-Ac > CuO-Ni > CuO-Su. From structural results, it could be observed that all the samples crystallized into a monoclinic crystal structure. The photocatalytic activity of CuO samples was evaluated by the catalytic oxidation of methylene blue in the presence of hydrogen peroxide. Concerning the nearly same optical band gap for the samples, the best photocatalytic performance of CuO-Ni nanorods was assigned to its highest active surface area and surface hydroxyl groups.

Intrinsic Peroxidase‐like Activity of Porous CuO Micro‐/nanostructures with Clean Surface

AbstractPorous CuO micro‐/nanostructures with clean surface, prepared through Cu2(OH)2CO3 precursor followed by calcination in air, were proven to be an effective peroxidase mimic. They can quickly catalyze oxidation of the peroxidase substrate 3,3′,5,5′‐tetramethylbenzidine (TMB) in the presence of H2O2, producing a blue color. The obtained porous CuO micro‐/nanostructure have potential application in wastewater treatment. The apparent steady‐state kinetic parameter was studied with TMB as the substrate. In addition, the potential application of the porous CuO in wastewater treatment was demonstrated with phenol‐containing water as an example. Such investigation not only confirms the intrinsic peroxidase‐like activity of micro‐/nanostructured CuO, but also suggests its potential application in wastewater treatment.

Fabrication of CuZn5–ZnO–CuO micro–nano binary superhydrophobic surfaces of Cassie–Baxter and Gecko model on zinc substrates

Superhydrophobic surfaces were prepared via immersing the clean perpendicular zinc substrates into aqueous copper chloride (CuCl2) solution and followed by annealing in dry air. Two Superhydrophobic models were obtained by controlling the concentration of CuCl2 aqueous solution. One had a high water contact angle (CA) of 162 ± 2° with a small sliding angle SA of less than 2 ± 1°, which was identified with Cassie–Baxter model, the other had a high CA of larger than 150° with a high adhesion, which was identified with Gecko model. CuZn5–ZnO–CuO micro–nano binary structure leads to superhydrophobicity of the surface. Wettability and durability of surfaces were investigated and a theoretical explanation on superhydrophobic surfaces is presented. Durability test was carried out to study properties of the surface. Formation mechanism of the surface was also explained.

Hydrothermal synthesis of CuO micro-/nanostructures and their applications in the oxidative degradation of methylene blue and non-enzymatic sensing of glucose/H2O2

In this paper, we report on the amino acids-/citric acid-/tartaric acid-assisted morphologically controlled hydrothermal synthesis of micro-/nanostructured crystalline copper oxides (CuO). These oxides were characterized by means of X-ray diffraction, nitrogen sorption, scanning electron microscopy, Fourier transform infrared, and UV–visible spectroscopy. The surface area of metal oxides depends on the amino acid used in the synthesis. The formation mechanisms were proposed based on the experimental results, which show that amino acid/citric acid/tartaric acid and hydrothermal time play an important role in tuning the morphology and structure of CuO. The catalytic activity of as-synthesized CuO was demonstrated by catalytic oxidation of methylene blue in the presence of hydrogen peroxide (H2O2). CuO synthesized using tyrosine was found to be the best catalyst compared to a variety of CuO synthesized in this study. CuO (synthesized in this study)-modified electrodes were used for the construction of non-enzymatic sensors, which displayed excellent electrocatalytic response for the detection of H2O2 and glucose compared to conventional CuO. The high electrocatalytic response observed for the CuO synthesized using tyrosine can be correlated with the large surface area, which enhances the accessibility of H2O2/glucose molecule to the active site that results in high observed current. The methodology adopted in the present study provides a new platform for the fabrication of CuO-based high-performance glucose and other biosensors.

Zinc Oxide and Copper Oxide Nanostructures: Fundamentals and Applications

ABSTRACTCopper oxide (CuO) and zinc oxide (ZnO) nanostructures complement each other since CuO is unintentional p-type and ZnO unintentional n-type. Using the low temperature chemical growth approach, the effect on morphology of varying the pH of the grown ZnO nanostructures and CuO micro structures is monitored. For both materials the variation of the pH was found to lead to a large variation on the morphology achieved. The grown ZnO NRs and CuO micro flowers material were used to fabricate devices. We demonstrate results from ZnO nanorods (NRs)/polymer p-n hybrid heterojunctions chemically grown on paper and using a process on paper for light emitting diodes (LEDs) applications as well as some large area light emitting diodes LEDs. The growth of CuO micro flowers indicated good quality material for sensing applications. The grown CuO micro flowers were employed as pH sensors. The results indicated a superior performance as expect due to the catalytic properties of this material.

Formation of hierarchical CuO microcabbages as stable bionic superhydrophobic materials via a room-temperature solution-immersion process

A new hierarchical CuO architecture consisting of densely packed nanoplates and nanoribbons was directly fabricated on Cu foils via a room-temperature solution-immersion process. The architectures resembled cabbages both in the shape and structure, and the plates and ribbons served as the leafstalks and leaves of cabbages, respectively. By carefully monitoring the growth stages, it was found that self-assembled CuO nanoplates could be firstly formed on the Cu foils, and then CuO tiny flexible nanoribbons were grown from the edges of fresh plates. The effect of NaOH concentration on the morphology of CuO structures was discussed. Importantly, stable superhydrophobicity (contact angle CA = 155°), independent of pH value of the water droplets, was successfully observed for CuO microcabbages after modification. The wettability of other CuO micro- and nanoscale hierarchical surface structures fabricated using various NaOH concentrations was also presented. The realization of superhydrophobic bionic surfaces with a new hierarchical morphology of CuO will shed new insights in both the synthesis and application fields.

CuO micro plates from a 3D metallo-organic framework (MOF) of a binary copper(II) complex of N, N-bis(2-hydroxyethyl)glycine

The crystal structure of [Cu(Bic) 2] ( 1) (Bic − = N, N-bis(2-hydroxyethyl)glycinate), was determined by single-crystal X-ray diffraction techniques. [Cu(Bic) 2]: monoclinic system, space group P21/ n. In the complex, the copper atom is tetra coordinated by two oxygen atoms of the carboxylato groups and two nitrogen atoms of the bicinate ligand, forming a distorted square planar coordination geometry. The molecular structure of the complex in solution is the same as that of the crystalline state, as supported by ESR and electronic spectra in solution. The blue complex 1 on heating at ∼500 °C for 6 h results in the formation of black CuO (Tenorite) micro plates.

Laser-induced synthesis of Al 2O 3/Cu-nanop article mixtures

Nanoscaled powder mixtures of the binary system Al 2O 3 and Cu are produced by laser ablation from pressed Al 2O 3 and CuO micro powder mixtures of various compositions with the pulsed radiation of a 1000W Nd: YAG-laser followed by condensation of the induced vapor in argon and hydrogen. The generated nanoparticles are analyzed regarding their grain size, crystalline structure and phase distribution in the powder by X-ray diffraction and transmission electron microscopy (TEM). The results reveal that any powder composition can be produced and that the different nanoparticle components are homogeneously distributed in the powder.