CuO Content Research Articles

Microstructure and vacuum arc characteristics of CuO skeletal structure Ag-CuO contact materials

In this paper, the novel Ag-45CuO contact materials with CuO skeletal structure were successfully prepared by high energy ball milling and hot pressing technology. The microstructure and vacuum arc characteristics of CuO skeletal structure Ag-45CuO materials were investigated. The as milled Ag-CuO powders were structurally characterized by X-ray diffraction (XRD). The microstructure and arc eroded surface morphologies of CuO skeletal structure Ag-45CuO materials were characterized by Scanning Electron Microscopy (SEM). Vickers microhardness and conductivity tests were conducted to determine the mechanical properties of the Ag-CuO samples. The results show that CuO skeletal structure in Ag-45CuO materials has formed and exhibit homogeneous CuO skeletal microstructure. With the CuO content increase from 20 wt.% to 45 wt.%, it was found that the microhardness increased over 2 times and the arc erosion areas decreased obviously, which indicates that the anti-arc erosion characteristic of CuO skeletal structure Ag-45CuO materials can be improved significantly.

Effect of copper-doped silicate 13–93 bioactive glass scaffolds on the response of MC3T3-E1 cells in vitro and on bone regeneration and angiogenesis in rat calvarial defects in vivo

The release of inorganic ions from biomaterials could provide an alternative approach to the use of growth factors for improving tissue healing. In the present study, the release of copper (Cu) ions from bioactive silicate (13–93) glass scaffolds on the response of cells in vitro and on bone regeneration and angiogenesis in vivo was studied. Scaffolds doped with varying concentrations of Cu (0–2.0wt.% CuO) were created with a grid-like microstructure by robotic deposition. When immersed in simulated body fluid in vitro, the Cu-doped scaffolds released Cu ions into the medium in a dose-dependent manner and converted partially to hydroxyapatite. The proliferation and alkaline phosphatase activity of pre-osteoblastic MC3T3-E1 cells cultured on the scaffolds were not affected by 0.4 and 0.8wt.% CuO in the glass but they were significantly reduced by 2.0wt.% CuO. The percent new bone that infiltrated the scaffolds implanted for 6weeks in rat calvarial defects (46±8%) was not significantly affected by 0.4 or 0.8wt.% CuO in the glass whereas it was significantly inhibited (0.8±0.7%) in the scaffolds doped with 2.0wt.% CuO. The area of new blood vessels in the fibrous tissue that infiltrated the scaffolds increased with CuO content of the glass and was significantly higher for the scaffolds doped with 2.0wt.% CuO. Loading the scaffolds with bone morphogenetic protein-2 (1μg/defect) significantly enhanced bone infiltration and reduced fibrous tissue in the scaffolds. These results showed that doping the 13–93 glass scaffolds with up to 0.8wt.% CuO did not affect their biocompatibility whereas 2.0wt.% CuO was toxic to cells and detrimental to bone regeneration.

Effect of CuO as a dopant in TiO2 on ammonia and hydrogen sulphide sensing at room temperature

The heterogeneous nanocomposites of CuO doped TiO2 nanoparticles were synthesized using sol gel method by varying the concentration of CuO as 0.1, 0.5 and 1mol% for the sensing of ammonia and hydrogen sulphide. The substitutional doping of CuO in TiO2 matrix was confirmed by the X-ray diffraction. Average crystallite size of the doped nanocomposites was found to reduce with increase in concentration of CuO. The 0.1mol% CuO doped TiO2 nanocomposites showed highest sensitivity to ammonia (97%) with response time of 2s, while 1mol% was selective to H2S gas (77%) with response time of 45s for 50ppm of each gas at room temperature.

Influence of CuO and Al2O3 addition on the optical properties of sodium zinc phosphate glass absorption filters

The phosphate glasses having chemical composition of 45P2O5-(35-y)ZnO-(20-x)Na2O-xCuO-yAl2O3 (0≤x≤5, 0≤y≤4) have been prepared using the melt quenching technique. XRD analysis has been carried out on the investigated samples in order for confirming the amorphous nature. The density has been measured using Archimedes method and then the molar volume has been calculated. It is found that the density, unlike molar volume, increases with increasing CuO content. This is due to the difference in atomic weight between Cu and Na. Addition of Al2O3 causes a slight decrease in density and a large increase in molar volume. The ionic concentration, inter ionic distance and oxygen packing density have been calculated for all investigated glasses. Using optical absorption, the optical bandgap has been calculated and found to decrease with increasing CuO concentration. This decrease becomes slower in the presence of Al2O3 which makes an increase in the bandgap at the the absence of CuO. The transmission spectrum of the investigated glasses shows that the samples containing CuO behave as bandpass filters. the characterized parameters of these filters, i.e. area, center, width, height and full wave half maximum (FWHM) of bandpass, have been estimated. These parameters have been found to be more affected by CuO and Al2O3 addition. The refractive index, extinction coefficient, real and imaginary part of the dielectric constant have also been calculated at the bandpass.

CuO catalysts supported on activated red mud for efficient catalytic carbon monoxide oxidation

Red mud was activated by digestion in hydrochloric acid and re-precipitation with ammonia, and the activated red mud (ARM) was used as the support for preparation of CuO/ARM catalysts by a simple deposition–precipitation method. The prepared catalysts possessed well-structured porosity and high surface area, as characterized by X-ray diffraction, Fourier transform infrared spectroscopy, H2-temperature-programmed reduction, X-ray photoelectron spectroscopy, and nitrogen sorption techniques. High activity was observed for CO oxidation on the resultant CuO/ARM catalysts, and the CuO content and precalcination temperature had significant impacts on the catalytic properties. The catalyst calcined at 200°C with 20% CuO loading amount demonstrated the highest catalytic activity, suggesting the CuO/ARM as a promising catalyst in the CO oxidation reaction, on the sake of the utilization of waste solids with much low cost of ARM.

One-dimensional Cu-based catalysts with layered Cu–Cu2O–CuO walls for the Rochow reaction

A series of copper catalysts with a core–shell or tubular structure containing various contents of Cu, Cu2O, and CuO were prepared via controlled oxidation of Cu nanowires (NWs) and used in the synthesis of dimethyldichlorosilane (M2) via the Rochow reaction. The Cu NWs were prepared from copper (II) nitrate using a solution-based reduction method. The samples were characterized by X-ray diffraction, thermogravimetric analysis, temperature-programmed reduction, X-ray photoelectron spectroscopy, transmission electron microscopy, and scanning electron microscopy. It was found that the morphology and composition of the catalysts could be tailored by varying the oxidation temperature and time. During the gradual oxidation of Cu NWs, the oxidation reaction initiated on the outer surface and gradually developed into the bulk of the NWs, leading to the formation of catalysts with various structures and layered compositions, e.g., Cu NWs with surface Cu2O, ternary Cu–Cu2O–CuO core–shell NWs, binary Cu2O–CuO nanotubes (NTs), and single CuO NTs. Among these catalysts, ternary Cu–Cu2O–CuO core–shell NWs exhibited superior M2 selectivity and Si conversion in the Rochow reaction. The enhanced catalytic performance was mainly attributed to improved mass and heat transfer resulting from the peculiar heterostructure and the synergistic effect among layered components. Our work indicated that the catalytic property of Cu-based nanoparticles can be improved by carefully controlling their structures and compositions.

Synthesis of ZnO/CuO nanocomposite immobilized on γ-Al2O3 and application for removal of methyl orange

ZnO/CuO nanocomposite immobilized on γ-Al2O3 was prepared by heterogeneous precipitation method. The composite was used as an adsorbent for the removal of anionic dye methyl orange (MO) from aqueous solution. The synthesized nanocomposites were studied by X- ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The SEM results showed that a layered structure was formed which was composed of nanostructured sheets. Thermodynamic parameters such as enthalpy change (ΔH°), entropy change (ΔS°) and free energy change (ΔG°) were also investigated. Free energy change showed that adsorption of methyl orange was spontaneous. The adsorption capacity increased with increasing CuO content, and the highest adsorption capacity of 341mg/g was obtained at calcination temperature of 400°C. The study showed that this nanocomposite can be considered a promising adsorbent to decontaminate water.

Dielectric properties and diffuse phase transition behavior of CuO-doped lead-free Ba(ZrxTi1−x)O3 ceramics

CuO-doped lead-free Ba(Zr0.2Ti0.8)O3 (BZT20) ceramics were prepared through a solid state processing technique, and the effects of CuO on microstructure, dielectric properties and diffuse phase transition behavior were investigated. The average grain sizes were increased by CuO doping. The temperature and frequency dependences of the dielectric constant revealed that CuO-doped BZT20 ceramics exhibited broad diffuse phase transition behavior. The dielectric constant increased with increasing CuO concentration. The value of Tm and degree of diffusion (γ) changed regularly in the studied compositional ranges. The BZT20 samples with 1.0mol% CuO doping, sintered at 1310°C, showed excellent dielectric property and lower diffusivity with εm=21,371 and γ=1.87. These results can be explained by the disordered distribution of Cu ions in the B sites and the weakened bonding force with oxygen ions in Cu substituted BZT20 structure.

Structure, optical properties and photocatalysis performance of Cu2O microspheres prepared by hydrothermal method

Cu2O microspheres have been prepared by means of hydrothermal method as a function of reaction temperature ranging from 70 to 130 °C. Microstructure, morphology, chemical composition, optical properties and photocatalysis performance of the as-received samples were investigated in detail. X-ray diffraction analysis shows that Cu2O and metal Cu content increase with increasing the reaction temperature. The samples are mainly composed of spherical particles and few Cu2O with octahedral structure emerges at 110 and 130 °C. X-ray photoelectron spectroscopy measurement indicates that the surface atom ratio of Cu and O is estimated about 2.3:1 for the sample prepared at 110 °C. UV–visible absorption spectra show that absorption edge appears red shift with the increase in the reaction temperature and the absorption intensity at the same time. After illuminated for 100 min, the decolorization rates of the samples obtained at 110 and 130 °C are above 80 %.

Physico-Chemical and Catalytic Properties of Mesoporous CuO-ZrO2 Catalysts

Mesoporous CuO-ZrO2 catalysts were prepared and calcined at 500 °C. The performance of the synthesized catalysts for benzylation of benzene using benzyl chloride was studied. The bare support (macroporous ZrO2) offered 45% benzyl chloride conversion after reaction time of 10 h at 75 °C. Significant increase in benzyl chloride conversion (98%) was observed after CuO loading (10 wt. %) on porous ZrO2 support. The conversion was decreased to 80% with increase of CuO loading to 20 wt. %. Different characterization techniques (XRD, Raman, diffuse reflectance UV-vis, N2-physisorption, H2-TPR, XPS and acidity measurements) were used to evaluate physico-chemical properties of CuO-ZrO2 catalysts; the results showed that the surface and structural characteristics of the ZrO2 phase as well as the interaction between CuO-ZrO2 species depend strongly on the CuO content. The results also indicated that ZrO2 support was comprised of monoclinic and tetragonal phases with macropores. An increase of the volume of monoclinic ZrO2 phase was observed after impregnation of 10 wt. % of CuO; however, stabilization of tetragonal ZrO2 phase was noticed after loading of 20 wt. % CuO. The presence of low-angle XRD peaks indicates that mesoscopic order is preserved in the calcined CuO-ZrO2 catalysts. XRD reflections due to CuO phase were not observed in case of 10 wt. % CuO supported ZrO2 sample; in contrast, the presence of crystalline CuO phase was observed in 20 wt. % CuO supported ZrO2 sample. The mesoporous 10 wt. % CuO supported ZrO2 catalyst showed stable catalytic activity for several reaction cycles. The observed high catalytic activity of this catalyst could be attributed to the presence of a higher number of dispersed interactive CuO (Cu2+-O-Zr4+) species, easy reducibility, and greater degree of accessible surface Lewis acid sites.

Impact of CuO phase on magnetocaloric and magnetotransport properties of La0.6Ca0.4MnO3 ceramic composites

We report the magnetocaloric and magneto-transport properties of the perovskites manganites composites (La0.6Ca0.4MnO3)/x(CuO) (LCMO/CuO) (x = 0.00, 0.07 and 0.18) synthesized by solid-state reaction method. X-ray diffraction (XRD) study was employed to confirm the formation of both the phases in composites. The results of magnetic measurements indicate that CuO mainly segregates at the grain boundaries of LCMO. Arrott analysis and master curve behavior reveal second order of magnetic phase transition in the composite samples. Magnetic entropy change increases with increasing CuO content and a maximum of 3 J/kg.K at 2 T has been observed in LCMO/(0.18)CuO sample. The detailed electrical characterizations showed that with increasing the CuO doping level, Tρ shifts to a lower temperature and the resistivity decreases. The low field magnetoresistance (LFMR) results from spin-polarized tunneling. However, around room temperature, the enhanced MR of the composites is caused by magnetic disorder. MR has been found to reach a maximum value of 30% at 2 T applied field with 18% CuO addition. The enhanced MR and ΔSM of these composites make them attractive for potential applications.

Protection Glass Eyewear Against a YAG Laser Based on a Bandpass Absorption Filter

In this article, copper zinc phosphate glass doped with 5 % barium oxide has an amazing optical property due to its application as bandpass filters. Typically, the glass conventional casting with chemical composition 42P2O5–(14- x)Na2O–39ZnO–5BaO–xCu2O where (x = 2, 4, 6, 8 and 10) was formed. The density was measured using the conventional Archimedes method and the molar volume was calculated. The change of glass structure was investigated using X-ray diffraction analysis (XRD). Distinctly, the results revealed that no crystal growth in all glass systems was observed. The density of glass samples was increased whereas the molar volume was decreased with increasing copper content. The absorption, transmission and reflection were measured and some other optical properties were calculated like UV cut-off, and IR cut-off. For instance, the visible cut-off started from 462 to 532 nm while the IR bonds were initiated at 630 to 1200 nm with 6 to 10 % Cu2O concentration.

Kinetic Study on the SO2 Adsorption using Adsorbent CuO/γ-Al2O3

Kinetic of SO 2 adsorption using adsorbent CuO/g-Al 2 O 3 has been studied with respect to the effect of SO 2 concentration and the amount of active phase on the kinetic of chemical adsorption between SO 2 and CuO. Adsorbent CuO/γ-Al 2 O 3 was prepared using the dry impregnation method with Cu(NO 3 ) 2 .3H 2 O solution on a commercial support, γ-Al 2 O 3 . Four types of the adsorbent CuO/g-Al 2 O 3 were prepared, with CuO contents represented as Cu of: 5, 8, 15 and 22%. Experiments on the adsorption were carried out at a temperature of 300°C. The model gas containing SO 2 with a concentration of 3000 or 18500 ppmv were passed at a constant flow rate in the range of 1.2 - 2.2 mL/sec through the bed of adsorbent for 1 hour. SO 2 adsorbed on CuO were analyzed based on the decrease in concentration of SO 2 between the inlet and the outlet of the adsorption column. The conversion of CuO to CuSO 4 was calculated based on the stoichiometry of reaction between SO 2 and CuO to form CuSO 4 . The increase in Cu content in the adsorbent decreased the conversion of CuO. In the adsorption using the model gas with SO 2 concentrations of 18500 and 3000 ppmv, the increase in Cu content in the adsorbent decreased the the reaction rate constant. Among various models under-consideration, the 3-D Difussion-Jander kinetic model was found to be the best to represent the experimental data.

Influence of CuO and ZnO addition on the multicomponent phosphate glasses: Spectroscopic studies

The spectra of phosphate-silicate glasses from the P2O5–SiO2–K2O–MgO–CaO system modified with the addition of CuO or ZnO have been studied by means of FTIR, Raman and 31P MAS NMR spectroscopy. All glasses were synthesized by the conventional melt-quenching technique and their homogeneous chemical composition was controlled and confirmed. By using the aforementioned research techniques, the presence of structural units with various degrees of polymerization was shown in the structure of analyzed phosphate-silicate glasses: Q3, Q2, Q1 and Q0. It was found that an increase in the content of CuO or ZnO in the composition of analyzed glasses, which are introduced at the expense of decreasing amounts of CaO and MgO, has a different influence on the phospho-oxygen network. It was shown that copper ions cause its gradual polymerization, while zinc ions cause its depolymerization. At the same time, polymerization of the silico-oxygen subnetwork was found. Additionally, in the case of glasses containing increasing amounts of ZnO, a change of the role of zinc ions in the vitreous matrix was confirmed (from the modifier to a structure-forming component).

PTCR Behavior of CuO-Doped Ba0.96(Bi0.5K0.5)0.04TiO3 Ceramics

As a candidate of a lead-free positive temperature coefficient of resistivity (PTCR) material, Ba0.96(Bi0.5K0.5)0.04TiO3-xCuO (x = 0–0.80%) ceramics were prepared by the solid-state reaction technique. X-ray diffraction results indicated that the CuO doped Ba0.96(Bi0.5K0.5)0.04TiO3 ceramics sintered at 1360°C for 3h in N2 exhibited a tetragonal structure at room temperature. The PTCR characteristics of Ba0.96(Bi0.5K0.5)0.04TiO3-xCuO ceramics were investigated in terms of CuO content. The undoped sample sintered in N2 showed low resistivity and a small resistance jump. With the increasing CuO content, both the Curie temperature and the room-temperature resistivity increased. The Raman scattering spectra showed that the Cu2+ was partly reduced to Cu+ during sintered in N2 which increased the density of the grain surface acceptors and enhanced PTC effect without reoxidation process. In the range of 0.05 ≤ x ≤ 0.20%, the samples displayed a marked PTC effect. When x ≥ 0.40%, CuO and Cu2O in ceramic samples could act as sintering aids to promote grain growth and all the samples showed NTC effect.

A P/N type compounded Cu2O/TiO2 photo-catalytic membrane for organic pollutant degradation

A heterojunction thin film consisting of n-type titanium dioxide (TiO2) and p-type cuprous oxide (Cu2O) was fabricated on an FTO conducting glass. The TiO2 films were grown on the FTO glass by sol–gel and spray pyrolysis methods, and Cu2O was deposited on it via the hydrothermal method. The morphology, crystalline structure, and optical absorption characteristics were studied by scanning electron microscopy, X-ray diffraction, and ultraviolet–visible diffuse reflectance spectrum, respectively. The results show that the surface of the Cu2O/TiO2 film was composed of net and large grains, which contributed to a large specific surface area. The crystal phase of the TiO2 in the Cu2O/TiO2 film remained anatase. The crystal phase of the Cu2O could not be detected as it is found in traces. The Cu2O/TiO2 film had a stronger optical absorption ability than the pure TiO2 film. To investigate catalytic activity, a photocatalytic degradation experiment of the Cu2O/TiO2 film was performed in a homemade thin-layer micro-reactor. The photocatalytic degradation of methylene blue increased with increasing amounts of deposited Cu2O until a maximum limit was reached. The photocatalytic activity might have declined with an increase in Cu2O content. The metallic oxide has the potential to screen other photocatalysts from the UV source.

Effects of CuO nanoparticles on Lemna minor.

BackgroundCopper dioxide nanoparticles (NPs), which is a kind of important and widely used metal oxide NP, eventually reaches a water body through wastewater and urban runoff. Ecotoxicological studies of this kind of NPs effects on hydrophyte are very limited at present. Lemna minor was exposed to media with different concentrations of CuO NPs, bulk CuO, and two times concentration of Cu2+ released from CuO NPs in culture media. The changes in plant growth, chlorophyll content, antioxidant defense enzyme activities [i.e., peroxidase (POD), catalase (CAT), superoxide dismutase (SOD) activities], and malondialdehyde (MDA) content were measured in the present study. The particle size of CuO NPs and the zeta potential of CuO NPs and bulk CuO in the culture media were also analyzed to complementally evaluate their toxicity on duckweed.ResultResults showed that CuO NPs inhibited the plant growth at lower concentration than bulk CuO. L. minor roots were easily broken in CuO NPs media under the experimental condition, and the inhibition occurred only partly because CuO NPs released Cu2+ in the culture media. The POD, SOD, and CAT activities of L. minor increased when the plants were exposed to CuO NPs, bulk CuO NPs and two times the concentration of Cu2+ released from CuO NPs in culture media, but the increase of these enzymes were the highest in CuO NPs media among the three kinds of materials. The MDA content was significantly increased compared with that of the control from 50 mg L−1 CuO NP concentration in culture media.ConclusionCuO NPs has more toxicity on L. minor compared with that of bulk CuO, and the inhibition occurred only partly because released Cu2+ in the culture media. The plant accumulated more reactive oxygen species in the CuO NP media than in the same concentration of bulk CuO. The plant cell encountered serious damage when the CuO NP concentration reached 50 mg L−1 in culture media. The toxicology of CuO NP on hydrophytes must be considered because that hydrophytes are the basic of aquatic ecosystem.

Influence on structure and properties of CuO addition to KNN–LS–BF piezoelectric ceramics

(1 − x)[0.98(0.95Na0.5K0.5NbO3–0.05LiSbO3)–0.02BiFeO3]–xmol%CuO (KNN–LS–BF–xCuO) lead-free piezoelectric ceramics have been synthesized by the conventional solid-state reaction process. It is found that the addition of CuO has not changed the phase structure of KNN–LS–BF ceramics, but has significant influence on their crystalline structure and properties. The SEM images reveal that the amount of holes are reduced and the grain become more tightly arranged as the CuO content x increasing. With the increase of CuO content x, the d 33 , k p , tanδ, Q m exhibit different variation trend and have been improved obviously when x < 0.15, but excessive CuO would degrade the comprehensive properties of KNN–LS–BF–xCuO ceramics. The best specimens of KNN–LS–BF–xCuO ceramics were fabricated when x = 0.15 at 1060 °C, relating constants respectively are: d 33 = 243pC/N, k p = 0.40, e r = 1506, tanδ = 2.85 %, Q m = 21.87.

Densification behavior and electrical properties of CuO-doped Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 ternary ceramics

CuO modified Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 (PIN–PMN–PT) ternary relaxor based ferroelectrics with the composition near the morphotropic phase boundary were synthesized by two-step columbite precursor method. The introduction of CuO significantly improved the sinterability of PIN–PMN–PT ceramics, resulting in the full densification of samples at lower sintering temperatures. It also profoundly modified the crystal structure and fracture mode of the ceramics. Properly increasing CuO content led to the disappearance of rhombohedral-tetragonal phase transition, remarkably improved the Curie temperature (Tc), and made the ceramics more relaxorlike. The ternary ceramics doped with 0.25wt% CuO possessed optimum piezoelectric properties (d33=584pC/N, d33*=948pC/N, and kp=0.68), high ferroelectric properties (Ec=9.9kV/cm, and Pr=33.1μC/cm2), low dielectric loss (tan δ=0.9%), and wider temperature usage range (Tc=225°C). The obtained properties are much higher than those of previously reported PIN–PMN–PT based ceramics, indicating that CuO doped PIN–PMN–PT is a promising candidate for electromechanical applications with high performance and wide temperature/electric field usage ranges.

Au/CuO–CeO2 catalyst for preferential oxidation of CO in hydrogen-rich stream: Effect of CuO content

A series of Au/CuO–CeO2 with various amounts of CuO was prepared. CuO–CeO2 was prepared by co-precipitation and Au was loaded by deposition–precipitation. The aim of this study was to develop a catalyst which is highly active and selective in preferential oxidation of CO in hydrogen stream (PROX). These catalysts were characterized by N2-sorption, XRD, TEM, HR-TEM, and XPS. The PROX reaction was carried out in a fixed bed continuous flow reactor with a feed of CO: O2: H2: He = 1.33: 1.33: 65.33: 32.01 in volume ratios. The incorporation of copper ion into ceria lattice increased the oxygen storage capacity of ceria and enhanced the activity of the catalyst. The excess CuO would present on the surface of CeO2. Au particles were well dispersed well on the support and the particle size of gold was in the range of 2 and 4 nm. Au was the active species and CuO played the promoter role. Those CuO presented on the surface of CeO had negative effect for CO oxidation. The selectivity of oxygen reacting with CO increased with increasing CuO content. Adding suitable amount of CuO in Au/CeO2 is beneficial for CO conversion and suppressing hydrogen oxidation in fuel cell operation condition.