Properties Of Cu Research Articles

The Regulation of Surface Copper Species Coupled with Ammonia-Evaporation and Hydrothermal Aging Process to Enhance Catalytic Hydrogenation Properties of Cu–SiO2 Catalysts

The Regulation of Surface Copper Species Coupled with Ammonia-Evaporation and Hydrothermal Aging Process to Enhance Catalytic Hydrogenation Properties of Cu–SiO2 Catalysts

Various dopant elements impact on the density of state of ternary CuSbSe2 chalcostibite: A theoretical study

This work aims to study the doping effect of B, Al, and Bi elements on the electronic distribution of CuSbSe2 compounds. The structural and electronic properties of Cu(1-x)AxSbSe2 and CuSb(1-y)XySe2 (A = B and Al, X = Al and Bi) were investigated by GGA-PBE and GGA-PBE + SIC approximations. Where x and y take values of 0%, 3%, 5%, 7%, and 10%. The optical properties of the pristine CuSbSe2 were calculated using the WIEN2K package based on the GGA-PBE and GGA-PBE + mBJ. The transport properties of CuSbSe2 were realised through the BoltzTraP package combined with the WIEN2K code using the GGA-PBE approximation. The electronic properties prove the n-type semiconductor with a direct bandgap of 0.68 eV. The optical properties of the pristine semiconductor make it a promising candidate for photovoltaic applications. Furthermore, a transition from semiconductor to metallic behavior is observed after doping with B and Bi elements.

Effect of Ti additions on microstructure and mechanical properties of Cu–Cr–Zr alloy

Ti additions in Cu–Cr–Zr alloys are useful for achieving high mechanical properties. In this work, the influence of Ti contents (0.25 wt%, 0.6 wt%, and 1.02 wt%) on the microstructure, mechanical, and electrical properties of Cu–Cr–Zr alloys has been investigated experimentally, along with thermodynamic and kinetic calculations. The electrical conductivity decreased but the hardness/strength increased with increasing Ti content. The lower electrical conductivity is due to increased electron scattering through the solution of more Ti atoms in the Cu matrix. As for the higher hardness/strength, it is mainly owing to higher dislocation density and finer FCC-Cr precipitates. Furthermore, a model considering the size distributions of precipitates is adopted to calculate precipitation strengthening quantitatively. The calculated yield strengths are consistent with the experimental ones for the alloys. The thermodynamic and kinetic calculations reveal that increasing Ti content can facilitate the nucleation of FCC-Cr but enhance its activation energy, hence hindering the growth process. The present work study can provide an effective strategy for producing copper alloys with expected performance.

Effects of Ag content and the annealing process on the microstructure and properties of Cu–7Mn–Ag–0.2Ce–0.2Zr resistor alloys

Designing alloys with a low resistance over a wide temperature range, specifically a low temperature coefficient of resistance (TCR), remains a great challenge from a material application perspective. In this study, the effects of Ag content and the annealing process on the microstructure, resistivity, TCR, hardness, and electrochemical corrosion properties of a Cu–7Mn–Ag–0.2Ce–0.2Zr resistance alloys were investigated. The results indicate that adding Ag to the Cu–Mn alloy can improve the solid solubility and change the lattice constant, resulting in a lower resistivity, TCR and better corrosion resistance. The hardness of the alloy increases because Ag segregates and is dispersed in the matrix to form a second phase during the annealing process. The Cu–7Mn–0.5Ag–0.2Ce–0.2Zr alloy performs the best, with a resistivity of 24.1 μΩ·cm and a TCR of 76 × 10−6/°C at 300 °C for 1 h. The alloy had low resistivity and TCR over a wide temperature range, and it also had high stability as well as long-term performance.

Charge transfer, electronic transport and magnetic properties of Cu[formula omitted]Ni[formula omitted]/reduced graphene oxide nanocomposites

Nanocomposites of magnetic nanoparticles and graphene based C structures that have finite band gap are promising materials for spintronic applications. Tuning the electronic transport and magnetic properties of such nanocomposites by the nanoparticle magnetism is desirable, and studying the underlying mechanism is intriguing. In the present work, we study the electronic transport and magnetic properties of nanocomposites of reduced graphene oxide and an alloy system Cu1−xNix (0≤x≤1) that undergoes a composition induced paramagnetic to ferromagnetic phase transition at x=xc=0.44. The nanocomposites are prepared using a combination of modified Hummer’s and reflux methods. Imaging, diffraction and spectroscopy results ascertain desired crystallinity and phase formation. Raman spectra indicate a charge transfer from the RGO sheets to the nanocomposites. Density functional theory computations confirm the occurrence of charge transfer. Electrical resistivities of the nanocomposites are found to follow thermally activated band conduction mechanism, akin to disordered semiconductors. The x-variation of activation energy is explicable in terms of the nanocomposite magnetization, which diverges at xc. Thus, the magnetism of the nanoparticles is shown to tune the electronic transport and magnetic properties of the nanocomposites via charge transfer.

Cu–Ce substituted cobalt nano ferrite - Structural, morphological, and magnetic behavior prepared by sol-gel auto-combustion

Sol-gel auto-combustion synthesized Co1-xCuxFe2-yCeyO4 (x = 0.0, 0.25, 0.5 and 0.75; y = 0.0, 0.03, 0.06, and 0.09), Cu–Ce substituted Co ferrite nanopowders. Investigations have been done on how Cu–Ce substitution affects the structural and magnetic characteristics. The Cu–Ce substitution variation effect on structural and magnetic properties is studied with X-ray diffraction (XRD), Field effect scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), and Vibrating sample magnetometer (VSM). The XRD was used to identify the crystal phase, and the role of Cu–Ce substituted for Co indicates how it formed. There is no change in the crystal structure, and no additional characteristic peak linked to Cu2+ and Ce3+ ions substitution was found in the XRD. The powder was sintered at 1100 °C. The crystallite sizes were found in between 33 and 62 nm. Increasing the Cu–Ce content decreases the lattice constant and is found between 8.4044 and 8.3309 Å. The FESEM images were used to analyze the nanostructural properties. The range of 110–128 nm is the value of average grain size. Two vibrational bands can be seen in FTIR spectra at about 600 cm−1 (v1) and 400 cm−1 (v2). They are attributed to the spinel lattices A and B sites, respectively. The tetrahedral site has a greater vibrational frequency of 566.09 cm−1, while the octahedral site has a lower vibrational frequency of 420.09 cm−1. FTIR spectra show the tetrahedral stretching peaks shifting towards lower frequencies with increasing Cu2+ and Ce3+ ions content. At ambient temperature, the magnetic properties of Cu–Ce substituted cobalt ferrites revealed a strong hysteresis loop. There was a decrease in magnetic saturation and an increase in coercivity.

Ultra-Low Lattice Thermal Conductivity Enables High Thermoelectric Properties in Cu and Y Codoped SnTe via Multi-Scale Composite Nanostructures

The eco-friendly thermoelectric material SnTe has recently gained immense attention due to its excellent thermoelectric properties and potential. However, its thermoelectric properties are limited by the inherent high carrier concentration (low Seebeck coefficient) and high thermal conductivity. Herein, we further introduce rare-earth element Y on top of the conventional Cu alloying to more effectively modulate its microstructure and thermal transport properties. The experimental results reveal that Y doping gives rise to band convergence, endowing Sn1–xYxTe-5%Cu2Te with an increased power factor of ∼22.14 μW cm–1 K–2. Meanwhile, the introduced abundant Y/Y2Te3 multiscale composite nanostructures in the matrix greatly enhance phonon scattering, resulting in an ultra-low lattice thermal conductivity of ∼0.43 W m–1 K–1. Consequently, these combined effects resulted in a peak ZT value of 1.27 at 823 K in Sn0.97Y0.03Te-5%Cu2Te. An enhancement of nearly 217% is achieved compared to pristine SnTe, which greatly improves the thermoelectric properties of SnTe-based materials.

The Effect of Boron Addition on the Structure and Mechanical Properties of Cu–Al–Ni–B Alloys with a Thermoelastic Martensitic Transformation

For the first time, data on the peculiarities of the structure of the Cu–Al–Ni–(B) alloys differing in the contents of alloying elements, namely, containing 10–14 wt % aluminum, 3, 4, 4.5 wt % nickel, and 0.02–0.3 wt % boron were obtained using optical, scanning, and transmission microscopy and X-ray diffraction analysis along with measurements of tensile mechanical properties. The effect of boron on the grain size, structure, phase composition, and mechanical properties of the shape-memory alloys has been studied. The localization of aluminum boride precipitates in the structure has been studied, and the effect of grain growthretardation in (α + β) and β Cu–Al–Ni–B alloys in both cast and heat-treated states has been found.

The Effect of Boron Addition on the Structure and Mechanical Properties of Cu–Al–Ni–B Alloys with a Thermoelastic Martensitic Transformation

The Effect of Boron Addition on the Structure and Mechanical Properties of Cu–Al–Ni–B Alloys with a Thermoelastic Martensitic Transformation

Powder metallurgy as a perfect technique for preparation of Cu–TiO2 composite by identifying their microstructure and optical properties

Powder metallurgy (PM) is a technique that involves the manufacturing of metal powders and their consolidation into finished products or components. This process involves the mixing of metal powders with other materials such as ceramics or polymers, followed by the application of heat and pressure to produce a solid, dense material. The use of PM has several advantages over traditional manufacturing techniques, including the ability to create complex shapes and the production of materials with improved properties. Cu–TiO2 composite materials are of great interest due to their unique properties, such as high electrical conductivity, improved mechanical strength, and enhanced catalytic activity. The synthesis of Cu–TiO2 composites using the PM technique has been gaining popularity in recent years due to its simplicity, cost-effectiveness, and ability to produce materials with excellent homogeneity. The novelty of using the PM technique for the preparation of Cu–TiO2 composite lies in the fact that it enables the production of materials with controlled microstructures and optical properties. The microstructure of the composite can be fine-tuned by controlling the particle size and distribution of the starting powders, as well as the processing parameters such as temperature, pressure, and sintering time. The optical properties of the composite can also be tailored by adjusting the size and distribution of the TiO2 particles, which can be used to control the absorption and scattering of light. This makes Cu–TiO2 composites particularly useful for applications such as photocatalysis and solar energy conversion. In summary, the use of Powder Metallurgy for the preparation of Cu–TiO2 composite is a novel and effective technique for producing materials with controlled microstructures and optical properties. The unique properties of Cu–TiO2 composites make them attractive for a wide range of applications in various fields, including energy, catalysis, and electronics.

Diving into the optoelectronic properties of Cu(II) and Zn(II) curcumin complexes: a DFT and wavefunction benchmark.

Curcumin is a popular food additive around the world whose medicinal properties have been known since ancient times. The literature has recently highlighted several biological properties, but besides the health-related usages, its natural yellowish color may also be helpful for light-harvesting applications. This research aims to close a knowledge gap regarding the photophysical description of curcumin and its metallic complexes. We conducted benchmark experiments comparing NEVPT calculations with several DFT functionals (B3LYP, M06-L, M06-2X, CAM-B3LYP, and ωB97X-D) for describing the UV spectra of curcumin and its metallo-derivative, curcumin-copper(II). Once we determined the most suitable functional, we performed tests with different basis sets and conditions, such as solvation and redox state, to identify their impact on excited state properties. These results are also reported for the curcumin-zinc(II) derivative. We found that the accuracy of DFT functionals depends strongly on the nature of curcumin's excitations. Intra-ligand transitions dominate the absorption spectra of the complexes. Curcumin absorption is marginally affected by solvation and chelation, but when combined with redox processes, they may result in significant modifications. This is because copper cation changes its coordination geometry in response to redox conditions, changing the spectrum. We found that, compared to a NEVPT reference, B3LYP is the best functional for a general description of the compounds, despite not being appropriate for charge transfer transitions. M06-L was the best for LMCT transitions. However, compared with NEVPT2 and PNO-LCCSD(T)-F12 results, no functional achieved acceptable accuracy for MLCT transitions.

Study of the microstructure and mechanical properties of Cu–Sn alloys formed by selective laser melting with different Sn contents

The microstructure and the mechanical properties of α-phase Cu–5Sn alloy, Cu–10Sn alloy, and Cu–15Sn alloy (wt.%) prepared by selective laser melting have been studied in this work. Under the same process condition, the laser absorption of the alloys increases continuously with the increase in Sn content. The optimal process parameters of the three alloys were obtained by Response Surface Method. The Sn content was found to have a significant effect on the relative density of the Cu–Sn alloys, as well as the laser power. The effect of laser power on the relative density of the alloys is weakened by the increase in laser absorption as the Sn content increases. Comparing the melt pool of the three alloys, they all show mainly columnar grains. As the Sn content increases, the size of the columnar grains becomes larger, and when the Sn content reaches 15 wt%, the columnar grains can penetrate through several melt pools. With the increase of Sn content from 5 wt% to 15 wt%, the tensile strength of the alloy increased from 382 MPa to 738 MPa, but the plasticity decreased significantly and the elongation decreased from 26% to 9%. As the Sn content increases from 5 to 15 wt%, the amount of solid-soluble Sn in the α-phase alloy increases, creating a lattice distortion stress field that effectively prevents dislocation movement. Thus, the stress field effectively increasing the yield and tensile strength of the alloy. Meanwhile, the increase in Sn content leads to the appearance of many brittle, hard and rich phases on the micron scale and precipitation from grain boundaries within the lattice, resulting in an increase in strength and a decrease in plasticity of the alloy. In conclusion, Cu–10Sn alloy has more excellent tensile properties and higher yield and tensile strengths with good ductility compared to Cu–5Sn and Cu–15Sn alloys.

Nanotechnology connecting copper metabolism and tumor therapy

AbstractCopper (Cu) is an essential trace element in the human body that is involved in the formation of several natural enzymes, such as superoxide dismutase and cyclooxygenase. Due to the high density of the outer electron cloud of Cu, which allows the transfer of multiple electrons, Cu is often used as the catalytic center in various metabolic enzymes. However, both deficiency and excessive accumulation of Cu can result in irreversible damage to cells. Therefore, strategies to regulate Cu metabolism, such as Cu exhaustion and Cu supplementation, have emerged as attractive approaches in anticancer therapy, due to the potential damages caused by Cu metabolism disorders. Notably, recent advancements in nanotechnology have enabled the development of nanomaterials that can regulate Cu metabolism, making this therapy applicable in vivo. In this review, we provide a systematic discussion of the physical and chemical properties of Cu and summarize the applications of nanotechnology in Cu metabolism‐based antitumor therapy. Finally, we outline the future directions and challenges of nano‐Cu therapy, emphasizing the scientific problems and technical bottlenecks that need to be addressed for successful clinical translation.

Effects of hexagonal boron nitride encapsulation on the electronic properties of Cu, Li, and O-doped black phosphorus monolayer

In this work, the structural and electronic properties of Cu, Li, and O-doped phosphorene/hexagonal boron nitride systems were studied based on density functional theory calculations. The intrinsic physical properties of the pristine phosphorene layer do not change with the addition of hexagonal boron nitride layers. While doping of phosphorene leads to strong binding energy at the interface, hence, improving the stability of the doped phosphorene/hexagonal boron nitride layers in systems. The electronic properties of the encapsulated systems change after doping. The band gap also decreases from 1.1200 eV in pristine encapsulated phosphorene to 0.3087, 0.0076, and 0.3100 eV in encapsulated phosphorene doped with Li, Cu, and O, respectively. The partial density of states and band structure diagrams show that the electronic properties of these systems shift from semiconductor to metallic behavior which can be exploited in electronic and optical applications.

Thermoluminescence properties of Cu doped α-Al2O3 crystals synthesized by a solid state method

While impurity doping in aluminum oxide (Al2O3) crystals has proven to be an efficient approach to enhance the material response to ionizing and nonionizing radiations, significantly less attention has been paid to thermoluminescence (TL) properties of copper doped Al2O3 (Al2O3:Cu) compounds. Here, Al2O3 microparticles (MPs) are synthesized and doped with different concentrations of Cu (0.1–1 mol%) using a solid state method. Scanning electron microscopy (SEM) was used to investigate the morphology and size of the synthesized MPs. The crystal structure and composition of the α-Al2O3 sample were studied by X-ray diffraction (XRD) and X-ray energy diffraction (EDX) analyses, respectively. The optimal amount of impurity for the maximum TL response to gamma rays of 60Co source was found to be 0.5 mol%. The kinetic parameters of the TL glow curve of the prepared samples were calculated by a computer fitting method. Also, the isothermal decay and variable heating rate methods were used to determine the activation energy and the frequency factor of the TL glow curve. Other TL properties of these MPs, including the TL glow curve, extinction and linear dose response region were also investigated.

Effect of Process Parameters on the Microstructure and Properties of Cu–Cr–Nb–Ti Alloy Manufactured by Selective Laser Melting

The fabrication of high-performance copper alloys by selective laser melting (SLM) is challenging, and establishing relationships between the process parameters and microstructures is necessary. In this study, Cu-Cr-Nb-Ti alloy is manufactured by SLM, and the microstructures of the alloy are investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), and electron backscatter diffraction (EBSD). The effects of processing parameters such as laser power and scanning speed on the relative density, defects, microstructures, mechanical properties, and electrical conductivity of the Cu-Cr-Nb-Ti alloy are studied. The optimal processing window for fabricating Cu-Cr-Nb-Ti alloy by SLM is determined. Face-centered cubic (FCC) Cu diffraction peaks shifting to small angles are observed, and there are no diffraction peaks related to the second phase. The grains of XY planes have a bimodal distribution with an average grain size of 24-55 μm. Fine second phases with sizes of less than 50 nm are obtained. The microhardness, tensile strength, and elongation of the Cu-Cr-Nb-Ti alloy manufactured using the optimum processing parameters, laser power of 325 W and scanning speed of 800 mm/s, are 139 HV0.2, 416 MPa, and 27.8%, respectively, and the electrical conductivity is 15.6% IACS (International Annealed Copper Standard). This study provides a feasible scheme for preparing copper alloys with excellent performance and complex geometries.

Base‐Controlled Chemoselective Reaction of High‐Valent Cu(III)−CF3Compounds with Anilines: Access to Formamides or Hydrazines

AbstractThis study reports reactivity properties of Cu(III)−CF3compounds with anilines, wherein basicity‐dictated distinct reactivities are achieved, giving rise to formamides or hydrazines. Competing generation of difluorocarbene andN‐centered radical is proposed that is controlled by the basicity of the reaction solution. Specifically, under acidic or neutral conditions, reaction of anilines with Cu(III)−CF3compounds produces formamides, where difluorocarbene is involved, undergoing aniline formylation. In contrast, in the presence of a base, this same reaction selectively gives hydrazines instead, where Cu(III)−CF3compounds act as an oxidizing reagent to allow dehydrogenative N−H/N−H coupling of two anilines through anN‐centered radical. The scope of both reactions is studied, and application to medicinally relevant compounds is shown. This study shows the unusual use of high‐valent Cu(III) trifluoromethyl compounds as hydrogen‐abstracting reagents to allow dehydrogenative reactions.magnified image

Oxidization‐Temperature‐Triggered Rapid Preparation of Large‐Area Single‐Crystal Cu(111) Foil

The controlled preparation of single-crystal Cu(111) is intensively investigated owing to the superior properties of Cu(111) and its advantages in synthesizing high-quality 2D materials, especially graphene. However, the accessibility of large-area single-crystal Cu(111) is still hindered by time-consuming, complicated, and high-cost preparation methods. Here, the oxidization-temperature-triggered rapid preparation of large-area single-crystal Cu(111) in which an area up to 320 cm2 is prepared within 60 min, and where low-temperature oxidization of polycrystalline Cu foil surface plays a vital role, is reported. A mechanism is proposed, by which the thin Cux O layer transforms to a Cu(111) seed layer on the surface of Cu to induce the formation of a large-area Cu(111) foil, which is supported by both experimental data and molecular dynamics simulation results. In addition, a large-size high-quality graphene film is synthesized on the single-crystal Cu(111) foil surface and the graphene/Cu(111) composites exhibit enhanced thermal conductivity and ductility compared to their polycrystalline counterpart. This work, therefore, not only provides a new avenue toward the monocrystallinity of Cu with specific planes but also contributes to improving the mass production of high-quality 2D materials.

Obtaining Methanol from CO2 on Cu–Zn/Al2O3 and Cu–Zn/SiO2 Catalysts: Effect of the Support and Conditions of the Reaction

A study is performed of the catalytic properties of Cu–Zn catalysts on Al2O3 and SiO2 supports (Acros) in the reaction of CO2 hydrogenation to obtain methanol. A sample of 30Cu15Zn/Al2O3 displays great selectivity toward methanol. A sample of 30Cu15Zn/SiO2 has the highest methanol performance. The methanol performance of a sample of 10Cu5Zn/Al2O3 is doubled when the pressure is raised from 10 to 30 atm, and a 94% increase in selectivity is observed. A sample of catalyst 10Cu5Zn/SiO2 does not lose its activity after 10 h of a catalytic reaction, and its methanol performance grows with repeated use

Obtaining Methanol from CO2 on Cu–Zn/Al2O3 and Cu–Zn/SiO2 Catalysts: Effect of the Support and Conditions of the Reaction

A study is performed of the catalytic properties of Cu–Zn catalysts on Al2O3 and SiO2 supports (Acros) in the reaction of CO2 hydrogenation to obtain methanol. A sample of 30Cu15Zn/Al2O3 displays great selectivity toward methanol. A sample of 30Cu15Zn/SiO2 has the highest methanol performance. The methanol performance of a sample of 10Cu5Zn/Al2O3 is doubled when the pressure is raised from 10 to 30 atm, and a 94% increase in selectivity is observed. A sample of catalyst 10Cu5Zn/SiO2 does not lose its activity after 10 h of a catalytic reaction, and its methanol performance grows with repeated use.