Copper Substitution Research Articles

Structural and Magnetic Properties of Copper-Substituted Nickel–Zinc Nanoparticles Prepared by Sol-Gel Method

Soft ferrite materials of high magnetic permeability and lower losses, essential to multilayer chip inductor applications, require stringent processing conditions to enable the materials with the desired characteristics. Copper-substituted Ni–Zn nanoferrite was processed through the sol-gel technique using polyvinyl alcohol as a chelating agent to control the particle size. The structural parameters and magnetic properties were examined by X-ray diffraction, field emission scanning electron microscopy (FESEM), Fourier-transform infrared spectroscopy and vibrating-sample magnetometer techniques respectively. FESEM images showed the formation of anisotropic structures like nanorods, nanoflower bouquet and nanofibres with copper substitution. The occupancy of copper ions towards octahedral sites has been ascertained by DC resistivity measurements, whereas the magnetic properties have been discussed based on cation distribution. The observed high values of magnetic permeability and DC resistivity suggest that the Ni–Zn ferrite system yields useful electromagnetic properties for smaller concentrations of copper substitution.

Impact of copper doping on perovskite structure ferroelectric ceramic

Copper doped Barium Titanate BaTi1-xMxO3 (x = 0.00, 0.02 and 0.04) perovskite ferroelectric ceramic synthesized by solid state reaction method. The crystal structure was determined by X-ray diffraction (XRD) studied. The lattice parameter and crystalline size were calculated by XRD data. The XRD data revealed that crystallite size of ferroelectric ceramic powder found to be decrease from 32.84 nm to 32.58 nm with substitution of copper. The effect of copper ion on crystallization process, SEM, EDAX and FTIR of BaTiO3 has been also investigated. In Present work Cu2+ doped BaTiO3 at B site may be used as an efficient material for sensor based application in electronic industry.

Enhanced bactericidal activity of brucite through partial copper substitution.

Brucite Mg(OH)2 belongs to a family of two-dimensional compounds with a CdI2-type structure built up from layers of edge-sharing octahedra delineating 2D galleries. In the current study, nanometer-sized platelets of copper substituted Mg(OH)2 were prepared by co-precipitation at room temperature in mixed alkaline (NaOH/Na2CO3) medium. Very weak substitution of a few hydroxyl ions by carbonate groups was highlighted at first by infrared spectroscopy and then quantified by thermogravimetric (TG) and mass spectrometric (MS) evolved gas analyses. The presence in a very low amount of water molecules in the galleries induces disorder in the stacking of layers of edge-sharing octahedra along the c-axis. The dehydration of the hydroxides taking place below 225 °C preserves the brucite-type structure of the samples while suppressing the stacking disorder. Copper substitution greatly enhances the bactericidal activity of nanometer-sized platelets of brucite against two bacteria frequently involved in healthcare-associated-infections. 10 mol% of cupric ions in Mg(OH)2 (a copper loading of 0.102 mg mL-1 in the suspension) were sufficient to induce, after 3 h in contact, 100% and 99.3% reductions in viability of Gram-negative E. coli and Gram-positive S. aureus, respectively (reductions as low as 23% and 48% are reported for the parent compound Mg(OH)2 in the same conditions). A good compromise between fast bactericidal kinetics and a high reduction in viability is reached by the 15 mol% copper-substituted Mg(OH)2 hydroxide. Its use gives the opportunity to five-fold reduce the copper loading of the bactericidal agent while being at least equally or even more efficient compared to the conventional CuO (a Cu loading of 0.799 mg mL-1 and 0.154 mg mL-1 in the suspension of CuO and 15 mol% copper substituted Mg(OH)2 particles, respectively).

Poly (3, 4-ethylene dioxythiophene) Supported Palladium Catalyst prepared by Galvanic Replacement Reaction for Methanol Tolerant Oxygen Reduction

Herein, we propose a facile electrochemical approach for the synthesis of Pd loaded poly 3, 4-ethylenedioxythiophene (PEDOT) electrodeposited on glassy carbon electrode (GCE) resulting in high surface area. The catalyst preparation is initiated with EDOT polymerization on GCE surface by electrochemical potential cycling method, followed by the electrodeposition of Cu from a 2 mM solution of CuSO4 in 0.1 M NaClO4 at a constant potential of +0.34 V vs. SHE in the form of Cu nanocubes on the PEDOT surface. Pd-PEDOT catalyst was then prepared by the partial substitution of copper by galvanic displacement with various concentrations of PdCl2. The prepared Pd/PEDOT electrocatalyst is found to be methanol resistant indicating its usefulness as fuel cell cathode. The prepared catalyst supports two electron transfer of oxygen reduction reaction in 0.5 M H2SO4. The effects of Pd and Cu contents and the quantity of PEDOT, mass and specific activities were studied. At a relatively low Pd loading of 0.57 ng/cm2, the Pd/PEDOT should be a cost-effective alternative cathode catalyst for direct methanol fuel cells, DMFCs. This work explains the usefulness of PEDOT as good catalyst supporting material which is prepared by an eco-friendly electrochemical route.

Synthesis and Characterisation of Copper Substituted Cobalt Ferrite Nanoparticles by Sol-Gel Auto Combustion Route

In the present study, the structural, functional, morphological and magnetic characteristics of copper substituted cobalt ferrite nanoparticles were investigated. The samples of Co1-xCuxFe2O4 at x = 0.06, 0.08 and 0.1 M were prepared by Sol-gel auto combustion route. X-ray diffraction technique was used to confirm the phase formation and structural analysis which matches with the JCPDS Data. The average crystallite size was found to be ∼25, ∼19 and ∼18 nm for x = 0.06, 0.08 and 0.1 respectively. The Micro Raman Spectroscopy revealed the stretching vibrations at 274 cm−1, 660 cm−1, and 466 cm−1, which are characteristic of Spinel Ferrites. From the FTIR analysis, the band observed at 3457cm−1 and 1650 cm−1 is assigned to hydrogen bonded O-H group and ionic stretching of C-H bond. The band assigned at 1105 cm−1, is due to Co – O and Cu - O or Fe – O vibrations. The existence of water adsorption band and metal oxygen band confirms the existence of Co and Cu in the synthesized sample. The surface morphology of samples was imaged by the field emission scanning electron microscope. The substitution of Cu2+ in the parent systems caused a significant reduction in particle size. The compositional analysis was done, which confirmed that the concentration of copper was increased in the samples. The samples were subjected to magnetic characterization because magnetic behavior is also affected by substitution of Copper in Cobalt ferrite. Magnetic hysteresis study at room temperature confirmed the reduction in saturation magnetization (MS = 14.25 to 8.33 emu/g.) and reduction in coercivity (HC = 602.64 to 380.94 Oe) when size is reduced. As the concentration of Cu into CoFe2O4 matrix increases, particle size decreases and the saturation magnetization decreases.

Synthesis and Characterization of Structural, and Electrical Properties of Mg(0.25x)Cu(0.25x)Zn(1 – 5x)Fe2O4 Ferrites by Sol-Gel Method

The effects of magnesium, copper, and zinc substitutions on spinel ferrites have been investigated by the sol-gel technique. Ferrite compositions of Mg0,25xCu0,25xZn(1−0,5x)Fe2O4 (where x = 0.6, 0.7, 0.8 & 0.9) were prepared at a sintering temperature of 1100 ∘C with a presintering at 500 ∘C. X-ray diffraction (XRD), scanning electron microscopy (SEM), and high-precision impedance analysis are used to characterize structural and dielectric properties, as well as the surface topography and morphology of the samples. A single phase, cubic spinel structure, with decreased lattice constant was observed. SEM micrographs revealed a homogeneous microstructure with uniform size distributions. Both the dielectric constant and dielectric loss tangent decrease, as the incident frequency increases up to a certain saturation point. The direct current (dc) resistivity profile shows that the resistivity increases with the temperature up to the Curie point, then it goes to a constant value. The quality factor (Q-factor) increases with the incident frequency. Hence, the high Q-factor will make ferrites highly useful in applications, especially in multilayer chip inductors.

Single-phase indium-doped cupric oxide films prepared through DC reactive magnetron sputtering: Influence of substrate temperature on microstructure, optical and electrical behavior

Cupric oxide (CuO) films with high electrical conductivity are crucial to their potential application in heterojunction solar cells. However, intrinsic CuO films usually have low electrical conductivity. The doping of proper ions into CuO is effective for the improved electrical conductivity. Herein, a series of monoclinic, indium-doped cupric oxide (CuO:In) films was prepared at different substrate temperature (Tsub) values via low-cost DC reactive magnetron sputtering. The influence of Tsub was intensively studied on the film’s microstructure, optical and electrical behaviors. A conducting transition from p type to n type occurs at 400 °C Tsub for CuO:In films rather than 500 °C Tsub for intrinsic CuO films. The decrease in critical transition temperature is mainly caused by the substitution of copper by indium. With increase of Tsub, the film crystallization is enhanced and the point defect content is reduced in the films, thereby increasing the film’s mobility and free carrier concentration. Increased Tsub helps the effective substitution of copper by indium and thus forms the n-type conduction. Compared with undoped CuO film, the CuO:In films have quite low mobility, improved electrical conductivity and large optical absorption edge. This finding indicates that CuO:In films can be used as absorption layer material in heterojunction solar cells rather than as hole-transporting layer material in perovskite solar cells.

Effect of copper substitution on structural, optical and humidity-sensing characteristics of cerium oxide nanoparticles

Cerium (pure) and copper-substituted cerium oxide nanoparticles were synthesized by microwave oven method. Powder X-ray diffraction showed that particle size was reduced with increases in copper content, termed the “particle size effect”. Scanning electron microscopy and transmission electron microscopy (TEM) images showed that particle formation was spherical. Miniature sizes of nanoparticles were in the range ~4–10 nm and were identified from typical TEM microstructures. Absorption peaks were reduced as result of copper content and binding energy was also reduced, which decreased the particle size. The particle size effect produced significant changes in humidity sensing, copper-substituted cerium oxide nanoparticles had better humidity-sensing behavior than pure cerium oxide. Reproducibility of the sensor produced notable sensing characteristics.

Effect of Copper Substitution on the Electrical Transport Properties of La<sub>0.7</sub>Ba<sub>0.1</sub>Sr<sub>0.2</sub>Mn<sub>1-</sub><i><sub>x</sub></i>Cu<i><sub>x</sub></i>O <sub>3</sub> (<i>X</i> = 0 and 0.05) Manganites

A systematic investigation of polycrystalline La0.7Ba0.1Sr0.2Mn1-xCuxO3 (x = 0 and 0.5) manganite has been conducted with a view to understand the effect of copper substitution on the electrical transport properties and its correlation with structural and morphological properties. The structural and morphological properties of the sample without copper content (x = 0) have been reported previously, while in this research, the structural and morphological properties of sample with 5% copper content (x = 0.5) will be reported. Structural comparison with previous research shows that 5% copper content does not change the rhombohedral structure of the sample without copper content. Comparison of resistivity (ρ) data with the theoretical model shows that the electrical properties of both samples are well described using the electron-electron, electron-phonon, electron-magnon, and kondo-like spin dependent scattering theory. Furthermore, percolation theory which have been used in the model shows that ferromagnetic phase and paramagnetic phase coexisted in both samples. Through copper substitution, the overall resistivity of the sample decrease compared to the sample without copper content. Furthermore, percolation theory demonstrates that ferromagnetic phase of the sample is decreasing as copper ions substituted manganese ion.

Copper-Substituted NiTiO3 Ilmenite-Type Materials for Oxygen Evolution Reaction.

Single Ni1-xCuxTiO3 (0.05 ≤ x ≤ 0.2) Ilmenite-type phases were successfully prepared through a solid-state reaction route using divalent metal nitrates as precursors and characterized. Their electrocatalytic performance for oxygen evolution reaction (OER) in alkaline media is presented. The Cu content was determined (0.05 ≤ x ≤ 0.2) by X-ray diffraction. A thorough powder neutron diffraction study was carried out to identify the subtle changes caused by copper substitution in the structure of NiTiO3. The evolution of the optical and magnetic properties with the Cu content was also investigated on the raw micrometer-sized particles. A reduction in particle size down to ≈15 nm was achieved by ball-milling the raw powder prepared by the solid-state reaction. The best catalytic activity for OER was obtained for nanometer-sized particles of Ni0.8Cu0.2TiO3 drop-casted on the Cu plate. For this electrode, a current density of 10 mA cm-2 for oxygen production was generated at 345 and 470 mV applied overpotentials with 1 and 0.1 M NaOH solutions as electrolytes, respectively. The catalyst retained this OER activity at 10 mA cm-2 for long-term electrolysis with a faradic efficiency of 90% for O2 production in a 0.1 M NaOH electrolyte.

Liquid interlayer formation during torsional ultrasonic welding of EN CW004A and EN AW1050

Due to the constantly increasing industrial requirements, such as cost reduction and energy efficiency, new challenges for manufacturing and joining technology are demanded. In the automotive industry, the onboard power system offers a good potential to save weight and costs of a vehicle. In this case, copper is increasingly substituted by aluminum to reach an improved energy efficiency by weight reduction and simultaneous cost reduction. In many industrial applications, a complete substitution of copper by aluminum is not possible; hence, mixed compounds have to be created. In this investigation, the joining of EN CW 004A and EN AW 1050 via a torsional ultrasonic welding process was observed. The influence of the amplitude on the bond formation and on the mechanical properties of the joint was analyzed. It was shown that a higher energy input was reached due to higher amplitudes. The metallographic evaluation revealed intermetallic phases and eutectic phases in the interface. The resulting eutectic phases consisted mainly of globular, disordered structures. As part of the mechanical investigation, the failure behavior and the failure load were analyzed via tensile shear test. Different failure characteristics depending on the plunging depth of the sonotrode and the welding temperature could be worked out.

Variations of the microstructure and the optical and electrical properties with sputtering power for direct-current-magnetron-sputtered indium-doped CuO thin films at room temperature

Preparation of single-phased indium-doped copper oxide (CuO:In) thin films with high quality at low temperature is crucial for the commercial application of CuO-based solar cells and light-emitting devices. Herein, direct-current magnetron sputtering assisted with high sputtering power and reactive pressure technique was used to prepare monoclinic CuO:In thin films at room temperature. The influence of sputtering power (Pspu) on the microstructure and the optical and electrical properties of the films were studied. The roles of indium in the CuO:In thin films were also proposed. CuO:In thin films are single-phased and monoclinic in structure. The crystallization and the preferred 〈−111〉 orientation of the films were enhanced with increased Pspu. The red shift of the film absorption edge was due to the decrease and increase of the lattice strains along crystal axes a and b with Pspu, respectively. A conducting transition from p type to n type of the films at 100 W Pspu was closely related to the increased substitution of copper by indium. The p- and n-type conductions of the films were mainly due to the copper vacancies and interstitials oxygen and to the effective substitution of copper by indium in the films, respectively. Increased Pspu increased the free carrier concentration and decreased the mobility of the films. The free carrier concentration reached the maxima of 9.333 × 1018 /cm3 at 100 W Pspu, whereas the mobility reached the maxima of 23.38 cm2/Vs at 60 W Pspu.

Enhancing stability of red perovskite nanocrystals through copper substitution for efficient light-emitting diodes

Red perovskite nanocrystals (NCs) are important for efficient perovskite light-emitting diodes (PeLEDs). However, the implementation of these red perovskite NCs are hindered because of their low structural stability. In the present work, highly stable and luminescent red perovskite CsPbBrI2 NCs were achieved through copper substitution and halide rich passivation strategy. Because the ion radius of Cu2+ (0.72 Å) is smaller than that of Pb2+ (1.19 Å), divalent Cu2+ cations can partly replace the Pb2+ ions in the lattice structure of CsPbBrI2 NCs. We demonstrated that the incorporation of Cu2+ ions can enhance formation energy, cause a slight lattice contraction, and hence stabilize the cubic phase of these NCs. On the other hand, Cu2+-substituted CsPbBrI2 NCs with higher luminescence were synthesized in a halide-rich passivation method. Benefiting from such an effective substitution and halide-rich strategy, these Cu2+-substituted CsPbBrI2 NCs has shown excellent performance with photoluminescence quantum yield (PL QY) (up to 94.8%) and an improved stability. The highly stable and luminescent Cu2+-substituted CsPbBrI2 NCs can function well as efficient light emitters toward the fabrication of high-performance red perovskite LEDs.

RETRACTED: Effect of copper substitution on the local chemical structure and dissolution property of copper-doped β-tricalcium phosphate

Substitution of inorganic ions into β-tricalcium phosphate (β-TCP) is a well-known approach for facilitating biological functions of bioceramics. However, the dissolution mechanism of those β-TCPs is still under intensive debates. In the present study, the effect of copper substitution into β-TCP crystal structure on the local chemical structure and dissolution property of the copper-doped β-TCP (CuTCP) was investigated to clarify the dissolution mechanism of β-TCP. A copper-dependent decrease in the dissolution rate of CuTCP with time was observed. The 1H → 31P nuclear magnetic resonance (NMR) spectra of 10 mol% copper-doped β-TCP after the dissolution test demonstrated an amorphous hydrated layer on the surface of β-TCP core particles, which contained hydroxyapatite and dicalcium phosphate dihydrate and anhydrate. As such, all the dissolution curves could be curve-fitted by a heterogeneous dissolution model composing of fast and slow dissolution components. Overall, dissolution mechanism could be proposed as follows: the CuTCP particles initially dissolved by hydrolysis based on the fast dissolution component. Subsequently, the amorphous hydrated layers were formed on their surface, and caused the diffusion-controlled dissolution. As the result, the slow dissolution component would be dominant, and led to the decreased dissolution rate. STATEMENT OF SIGNIFICANCE: Understanding the dissolution mechanism of copper doped β-tricalcium phosphate (CuTCP) is crucial for designing an angiogenetic controlled copper release CuTCP for therapeutic biomaterials. However, dissolution mechanism of β-TCP or CuTCP is still under intensive debates. This study demonstrated for the first time, that amorphous hydrated layers were formed on the CuTCP particle surface during its dissolution process, which caused a diffusion-controlled dissolution, and decreased the dissolution rate of CuTCP. This work not only provided a novel dissolution mechanism of β-TCP or CuTCP, but also a new finding for designing an angiogenetic controlled copper release CuTCP for therapeutic biomaterials.

Influencing the electrical properties of laser beam vacuum-welded Cu-Al mixed joints

A great potential for lightweight construction, above all in the field of electromobility, lies in the substitution of copper by aluminum. It is, moreover, possible to apply aluminum as a conductor and copper as a contact material (firmly bonded joining). During the fusion welding of this joint, brittle intermetallic phases occur which negatively affect the mechanical and technological properties of the joint. The high hardness of the intermetallic phases exerts a great influence on the load-bearing capability. Also, the electrical resistance of most intermetallic phases is one order of magnitude higher than that of the pure materials. The state of the art, so far, has put the focus only on the identification of the crack-sensitive intermetallic phase. External influential factors, such as temperature, current-feed, and time, bring about the change of the joining zone structure by diffusion and electromigration. Moreover, a temporal change of the technological properties (further increase of the electric resistance and reduction of strength) of the dissimilar material joint will occur. Findings about this behavior will allow one to draw conclusions about the expected lifetime of the joints. The research shows that the mixing during the welding process shows a great influence on the formation of intermetallic phases and thereby on the properties of the joint.

Frontispiece: A CO Adsorption Site Change Induced by Copper Substitution in a Ruthenium Catalyst for Enhanced CO Oxidation Activity

Frontispiece: A CO Adsorption Site Change Induced by Copper Substitution in a Ruthenium Catalyst for Enhanced CO Oxidation Activity

Frontispiz: A CO Adsorption Site Change Induced by Copper Substitution in a Ruthenium Catalyst for Enhanced CO Oxidation Activity

Frontispiz: A CO Adsorption Site Change Induced by Copper Substitution in a Ruthenium Catalyst for Enhanced CO Oxidation Activity

Copper trade and production of copper, brass and bronze goods in the Oldenburg monarchy: copperworks and copper users in the eighteenth century

ABSTRACTThis paper explores trade connections – or the lack of such – between copperworks and copper processing plants in the Oldenburg Monarchy in the eighteenth century. Domestic customs areas, high tariffs on raw material export and import bans sought to encourage domestic copper and brass goods production of Norwegian copper raw material, however this was only realised halfway. The raw material from Norway was largely exported, and copper and brass materials used to produce copper-, brass and bronze goods were imported from all over the world. The copperworks and processing plants in the Monarchy never became strongly integrated due to several reasons. First, shareholders of copperworks acquired favourable credit deals abroad, and preferred to export the copper, and second, copper materials had different features and processing plants used all sorts of copper inputs in the making of goods, not only copper raw material. Norway produced mostly gar copper, so copper plants and coppersmiths had to turn elsewhere for other types of copper. Production of copper and brass goods increased, but did not meet the domestic demand partly due to a strong foreign competition. The optimal goal of ‘mercantilist theory’ regarding copper and brass import substitution was not reached.

Citrate-gel preparation and ammonia synthesis activity of compounds in the quaternary (Ni,M)2Mo3N (M = Cu or Fe) systems.

Single phase solid solutions based on copper and iron substitution into the nickel sites of Ni2Mo3N are produced using a citrate gel approach followed by ammonolysis. These metal nitrides show good ammonia synthesis activity at 500 °C and ambient pressure. The activity fell with copper content and increased with iron content, although these changes appear to be related to the surface areas of the catalysts. The oxide intermediates from the citrate gel process cleanly converted to the metal nitride under the ammonia synthesis gas stream (75% H2, 25% N2) providing more active catalysts than those pre-nitrided by ammonolysis.

Improvement the Superconducting properties of TlBa2 Ca2 Cu3xNix O 9-δ superconducting compound by partial substitution of copper with nickel oxide on the

In this study is presented the partial replacement of copper with nickel TlBa2Ca2 Cu3xNix O9-δ superconductor with (x=0,0.2,0.4,0.6,0.8,1.0). The samples were prepared in a solid state reaction method with a 850 Co sintering temperature for 24 hours. Structural of the samples were studied by using X-ray powder. The XRD analysis showed that a tetragonal diagram and polycrystalline structures with a majority phase 1223 and changes in nickel concentrations resulted in a change in the parameters of lattice parameters a, b, c axis c / a, mass density and Volume fraction. Four prop technique were used to test the electrical resistivity to determine the critical temperature at zero resistance Tc(offset). The best transfer temperature was obtained from the TlBa2Ca2Cu2.4Ni0.6O9-δ sample, which is equal to 134.6 Kelvin.