Crystalline Copper Research Articles

Effective combination of CuFeO2 with high temperature resistant Nb-doped TiO2 nanotube arrays for CO2 photoelectric reduction

Herein, we report a simple approach to synthesize CuFeO2/TNNTs photocathodes composed of high-temperature resistance n-type Nb-doped TiO2 nanotube arrays (TNNTs) and p-type CuFeO2 for CO2 reduction. TNNTs were prepared by anodic oxidation on TiNb alloy sheets and CuFeO2/TNNTs were then prepared by coating precursor liquid onto TNNTs followed by heat treatment in argon atmosphere. The microstructures of CuFeO2/TNNTs and TNNTs before and after heat treatment were investigated by SEM and TEM. The phase compositions of CuFeO2/TNNTs were studied by XRD and XPS, and the light absorption performance were tested by UV–vis diffuse reflectance spectrum. Results show that TNNTs exhibit a regular nanotube arrays structure and this structure is well remained after the calcination at 650 °C. In addition, TNNTs show similar semiconductor properties to n-type TiO2, which enables them to be integrated with p-type CuFeO2 to obtain composite photocathodes with a p-n junction. The synthesized CuFeO2/TNNTs photocathode is well crystallized because no other crystalline iron or copper compounds are included in the prepared photocathode. Furthermore, the photocathode shows high light absorption and fast carrier transport due to the appropriate band gap and p-n junction. As a result, high photoelectrocatalytic CO2 reduction performance with high selectivity to ethanol is obtained on this photocathode.

Controlled growth of Cu and CuOx thin films from subvalent copper precursors.

A new Cu(i) precursor, [(COD)Cu(TFB-TFEA)] (COD = 1,5-cyclooctadiene and TFB-TFEA = N-(4,4,4-trifluorobut-1-en-3-on)-6,6,6-trifluoroethylamine) with high volatility and a clean thermal decomposition pattern was tested for thermal and plasma-assisted chemical vapor deposition (CVD). The heteroleptic configuration based on an anionic and a chelating neutral ligand unified both reactivity and sufficient stability resulting in an intrinsic molecular control over the composition of the resulting CVD deposits. The electronic influence of the ligand on the metal site was studied by 1D and 2D NMR spectroscopy, while EI mass spectrometry revealed the ligand elimination cascade. Thermal and plasma CVD experiments demonstrated the suitability of the copper compound for an atom-efficient (high molecule-to-material yield) deposition of copper(0) and copper(i) oxide films that could be converted into crystalline copper(ii) oxide upon heat treatment at 500 °C.

Gas-Sensing Activity of Amorphous Copper Oxide Porous Nanosheets.

In this paper, the gas‐sensing properties of copper oxide porous nanosheets in amorphous and highly crystalline states were comparatively investigated on the premise of almost the same specific surface area, morphology and size. Unexpectedly, the results show that amorphous copper oxide porous nanosheets have much better gas sensing properties than highly crystalline copper oxide to a serious of volatile organic compounds, and the lowest detection limit (LOD) of the amorphous copper oxide porous nanosheets to methanal is even up to 10 ppb. By contrast, the LOD of the highly crystalline copper oxide porous nanosheets to methanal is 95 ppb. Experiments prove that the oxygen vacancies contained in the amorphous copper oxide porous nanosheets play a key role in improving gas sensitivity, which greatly improve the chemical activity of the materials, especially for the adsorption of molecules containing oxygen‐groups such as methanal and oxygen.

Beyond linearity: bent crystalline copper nanowires in the small-to-moderate regime.

Several models can describe the nonlinear response of 1D objects to bending under a concentrated load. Successive stages consisting of geometrical and, additionally, mechanical non-linearity can be identified in moderately large extensions. We provide an explicit bending moment function with terms accounting for the linearity (Euler–Bernoulli), quasi-linearity, geometrical and finally, mechanical non-linearity as global features of a moderately large elastic deformation. We apply our method, also suitable for other metals, to the experimental data of Cu nanowires (NWs) with an aspect ratio of about 16 under different concentrated loadings. The spatial distribution of strain-hardening/softening along the wire or through the cross-section is also demonstrated. As a constitutive parameter, the strain-dependent stretch modulus represents, undoubtedly, changes in the material properties as the deformation progresses. At the highest load, the Green–Lagrange strain reaches a 12.5% extension with a corresponding ultra-high strength of about 7.45 GPa at the most strained volume still in the elastic regime. The determined stretch modulus indicates a significantly lower elastic response with an approximated Young's modulus (E ≅ 65 GPa) and a third-order elastic constant, C111 ≅ −350 GPa. Surprisingly, these constants suggest a 25–35% of that of the bulk counterparts. Ultimately, the method not only provides a quantitative description of the bent Cu NWs, but also indicates the robustness of the theory of nonlinear elasticity.

Predicting the flow stress and dominant yielding mechanisms: analytical models based on discrete dislocation plasticity

Dislocations are the carriers of plasticity in crystalline materials. Their collective interaction behavior is dependent on the strain rate and sample size. In small specimens, details of the nucleation process are of particular importance. In the present work, discrete dislocation dynamics (DDD) simulations are performed to investigate the dominant yielding mechanisms in single crystalline copper pillars with diameters ranging from 100 to 800 nm. Based on our simulations with different strain rates and sample size, we observe a transition of the relevant nucleation mechanism from “dislocation multiplication” to “surface nucleation”. Two physics-based analytical models are established to quantitatively predict this transition, showing a good agreement for different strain rates with our DDD simulation data and with available experimental data. Therefore, the proposed analytical models help to understand the interplay between different physical parameters and nucleation mechanisms and are well suitable to estimate the material strength for different material properties and under given loading conditions.

Pre-concentration and recovery of silver and indium from crystalline silicon and copper indium selenide photovoltaic panels

The circular use of critical raw materials is regarded as a topic of contemporary interest stimulating continuous research and development to reduce primary resource use and waste production. However, due to the low mass share of such materials in waste streams, the industrial sector mainly focuses on the recovery of bulk components (e.g. base metals). Even in laboratory-scale studies, the fate of critical raw materials through the recycling chain, and the important role of pre-concentration prior to selective recovery have not been sufficiently addressed. To this scope, this study evaluates the mass flow of Ag and In during the treatment of waste polycrystalline silicon and monocrystalline silicon, as well as copper indium selenide photovoltaic panels in order to produce valuable pre-concentrates of these metals. The treatment routes, used in various combinations, are (a) thermal treatment and gravimetric separation, (a) mechanical crushing, sieving and thermal treatment, as well as (c) chemical and thermal treatment of the panels. The pre-concentration yield was investigated assessing the content of Ag or In (mg/kg) in the treated mass share (%) as compared to the initial content and photovoltaic mass used. Then, the selective recovery of Ag or In from the produced treated fractions, which are enriched in Ag or In, was studied through acid leaching and precipitation. Thermal treatment and gravimetric separation resulted in intact target-components and optimal pre-concentration yield of Ag and In (91.42 and 94.25% for crystalline panels, and 96.10% for copper indium selenide panel). A maximum leaching capacity of Ag and In was obtained using HNO3 and H2SO4 solution, respectively. Pure silver chloride (AgCl) was recovered using HCl as precipitating agent and pure indium hydroxide (In2O3) using NH4OH. Overall, the study pointed out that waste photovoltaic panels are new and complex products that can be considered as secondary sources to recover Ag and In, when a suitable combination of treatment processes is applied.

An Electron-Poor Dioxa-[2.1.1]-(2,6)-pyridinophane Ligand and Its Application in Cu-Catalyzed Olefin Aziridination.

A novel macrocyclic 1,7-dioxa-[2.1.1]-(2,6)-pyridinophane ligand has been synthesized and crystallographically characterized. Two derived metal complexes, dichloropalladium(II) and chlorocopper(I), were prepared. In the palladium(II) complex LPdCl2, both in the solid state, according to its crystallographic characterization, and in CH2Cl2 solutions at -40 °C, according to 1H NMR spectroscopy, the ligand adapts a C1-symmetric κ2-N,N-coordination mode in which the metal atom binds to two nonequivalent pyridine fragments of the macrocycle. The complex is fluxional at 20 °C. In the crystalline copper(I) complex LCuCl, the macrocyclic ligand is also κ2-N,N-coordinated to the metal, but it utilizes two equivalent pyridine fragments for the binding. The copper(I) complex is fluxional in CH2Cl2 solutions in the temperature range between 20 and -70 °C and is proposed to be involved in a fast intermolecular macrocyclic ligand exchange which is slowed down below -40 °C. DFT calculations predict a lower thermodynamic stability of the dioxapyridinophane-derived complexes LPdCl2 and LCuCl, as compared to their [2.1.1]-(2,6)-pyridinophane analogs containing bridging CH2 groups instead of the oxygen atoms. The electron poor dioxapyridinophane chlorocopper(I) complex, in combination with NaBArF4 (BArF4 = tetrakis[3,5-bis(trifluoromethyl)phenyl]borate) in dichloromethane solutions, can serve as an efficient catalyst for aziridination of various olefins with PhINTs at 0-22 °C.

Comparison of Al and Cu masks used for patterning boron-doped diamonds in oxygen plasma

In this paper we investigate the influence of different metallic (or metal-based) masking materials and plasma techniques for etching and patterning polycrystalline boron-doped diamond thin films. Lift-off technique was used to prepare various testing mask patterns with dimensions ranging from 1 μm to 15 μm. The results of plasma etching utilizing 100 nm Al and Cu masks are compared. Radio frequency and inductively coupled pure oxygen plasma techniques were used to obtain the fine etched structures. A simple etching scheme describing the obtained results is presented for each type of plasma technique and mask type. Although the Al mask is widely believed to have outstanding properties over other metallic materials, we found that the Cu mask exhibits lower side edge etching for both types of plasma techniques. A formation of thick and crystalline copper oxide layer in contrast with thin amorphous aluminum oxide is believed to be the reason for this behavior. Consequently, the etched structures also possessed much better side wall angles which is a key parameter for micro-fabrication of boron doped diamond microelectrodes, microfluidics, sensors and microelectromechanical devices in general.

Analysis of EXAFS Spectra of Crystalline Copper using Classical Anharmonic Correlated Einstein Model

In this work, the temperature dependence of extended X-ray absorption fine structure (EXAFS) of the crystalline copper structure was calculated and analyzed using the anharmonic correlated Einstein model and the classical statistical theory. The thermodynamic parameters of a system are derived from an anharmonic effective potential that has taken into account the influence of all nearest neighbors of absorbing and backscattering atoms in the crystal lattice with thermal vibrations, where the Morse potential is assumed to characterize the interactions between each pair of atoms and the function of anharmonic EXAFS spectra presented in terms of the cumulant expansion up to the fourth-order. Analytical expressions for the first four cumulants and their contribution to amplitude reduction and phase shift obtained in the simple form of the mean-square relative displacement or the correlated Einstein frequency. The numerical results for crystalline copper were in good agreement with those obtained by the other theoretical procedures and experiments at several temperatures. The analytical results show that this calculation model is useful to reduce measurement and data analysis of experimental EXAFS spectra.

Sulfide precipitation of copper from alkaline glycine-cyanide solutions: Precipitate characterisation

A synergistic leaching system using glycine containing starvation levels of cyanide as lixiviants has been shown to be an effective approach to leach gold-copper ores, allowing the consumption of cyanide to be reduced significantly while glycine is recycled. Sulfide precipitation to remove the bulk of the copper was studied. The previous study on the precipitation behaviour of Cu and Au from the alkaline glycine-cyanide solution shows that the cupric (Cu2+) glycinate can be easily precipitated, while the gold and cuprous (Cu+) cyanide species remain stable in the solution. Due to the sparingly soluble nature of metal sulfides, colloidal and poorly settling particles are usually formed without control methods, which create challenges for solid-liquid separation processes such as thickening and filtration. This study investigated the effects of chemical and operational conditions on particle characteristics particularly particle size distributions (PSD). Settling characteristics, particle morphologies and particle structure were also studied. In the presence of divalent cations such as Ca2+ and Mg2+, particularly Ca2+, large and fast settling particle agglomerates were generated. Increasing ionic strength of the solution was also noted to enlarge the particles. The high supersaturation level has insignificant effects on the PSD as long as Ca2+ is present. A relatively large particle size is generated at a medium stirring speed with fast addition rate. There are no significant effects of aging, heating, and seeding on the PSD, but these factors profoundly influenced the morphologies of the individual particles according to the SEM results. SEM and XRD analysis illustrate that a more mature and crystalline copper sulfide precipitates were produced after aging, heating, or seeding.

Synthesis, characterization and biological evaluation of novel 2,2′-((1,2-diphenylethane-1,2-diylidene)bis(azanylylidene))bis(pyridin-3-ol)and metal complexes: molecular docking and in silico ADMET profile

A novel series of bio vital Schiff base ligand and transition metal complexes was prepared from benzil, 2-amino-3-hydroxy pyridine and metal chlorides. The synthesized compounds were characterized by physicochemical measurements like elemental analysis, magnetic susceptibility, molar conductance and multispectral analysis like Fourier transform, electronic absorption, nuclear magnetic resonance, electron paramagnetic resonance, ESI-mass spectroscopy, XRD and scanning electron microscopy. Based on the spectral results, the synthesized compounds are in crystalline nature and copper complex has square planar geometry. Conversely, cobalt, nickel and zinc complexes have tetrahedral geometry. Furthermore, the biological potential of the synthesized compounds is analysed by DNA binding and cleavage analysis and antimicrobial, anticancer, apoptosis and antioxidant inspections. The DNA binding analysis was performed using UV absorption titration and hydrodynamic experiments, which unveiled that the prepared compounds could be interconnected with calf thymus DNA by the way of intercalative mode. The mode of intercalation is further supported by docking investigations with nucleic acid and Bowman-Birk inhibitor. The DNA cleaving analysis implied that Cu(II) complex has eminent cleaving ability to split up the pUC18 DNA with an oxidising agent. Additionally, the anti-pathogenic screening studies explained that the complexes have antimicrobial skill against selected microbes. The anti-carcinogenic talent of the compounds is scrutinized on human cancer cell lines, which revealed that the prepared compounds possess good anticancer proficiency. During Hoechst staining analysis, the synthesized compounds have undergone the morphological moderations and succeeding cell death. The free radical scavenging investigations display that the metal complexes hold the suited talent to hunt the OH radical effectively. The prediction of in silico ADMET belongings found out that synthesized compounds acquire substantial drug-likeness characters based on Lipinski’s rules.

Metallic copper removal optimization from real wastewater using pulsed electrodeposition

The recovery of metals from wastewater is a recurrent problem due to numerous productive activities that produce wastewaters rich in toxic metals. Within this context, this research presents the study and optimization of copper recovery of real wastewater using pulsed electrodeposition. The studied parameters – method, current, temperature, and rotation– influence both the removal of Cu and the composition of the formed deposit, noting that the variation of these parameters enables the removal of copper with formation from crystalline oxides to crystalline copper in its metallic form. The process was optimized, and a 33.59% copper removal from a real wastewater with a deposition efficiency of 84.36% in 30 min was deemed optimal, using fast galvanic pulse, ton = 1 ms, 190 mA, 70 rpm, and 37 °C. For coating in the optimum point, a metallic and crystalline copper with 100% purity was obtained.

Elucidation of the Structure of a Thiol Functionalized Cu-tmpa Complex Anchored to Gold via a Self-Assembled Monolayer.

The structure of the copper complex of the 6-((1-butanethiol)oxy)-tris(2-pyridylmethyl)amine ligand (Cu-tmpa-O(CH2)4SH) anchored to a gold surface has been investigated. To enable covalent attachment of the complex to the gold surface, a heteromolecular self-assembled monolayer (SAM) of butanethiol and a thiol-substituted tmpa ligand was used. Subsequent formation of the immobilized copper complex by cyclic voltammetry in the presence of Cu(OTf)2 resulted in the formation of the anchored Cu-tmpa-O(CH2)4SH system which, according to scanning electron microscopy and X-ray diffraction, did not contain any accumulated copper nanoparticles or crystalline copper material. Electrochemical investigation of the heterogenized system barely showed any redox activity and lacked the typical CuII/I redox couple in contrast to the homogeneous complex in solution. The difference between the heterogenized system and the homogeneous complex was confirmed by X-ray photoelectron spectroscopy; the XPS spectrum did not show any satellite features of a CuII species but instead showed the presence of a CuI ion in a ∼2:3 ratio to nitrogen and a ∼2:7 ratio to sulfur. The +I oxidation state of the copper species was confirmed by the edge position in the X-ray absorption near-edge structure (XANES) region of the X-ray absorption spectrum. These results show that upon immobilization of Cu-tmpa-O(CH2)4SH, the resulting structure is not identical to the homogeneous CuII-tmpa complex. Upon anchoring, a novel CuI species is formed instead. This illustrates the importance of a thorough characterization of heterogenized molecular systems before drawing any conclusions regarding the structure–function relationships.

Thermodinamical Analyse the Formation of Phosphates Copper, Zinc and Cobalt on the Base Double Superphosphate and Sulphates of Copper, Zinc and Cobalt

In this article the relationship between the entropies of crystalline calcium compounds and copper, zinc and cobalt compounds were analyzed. Thermal capacity dependence of temperature for acidic phosphates of copper, zinc and cobalt, determining value of enthalpy and entropy of copper, zinc and cobalt phosphates have been determined and the possibility to conduct thermodynamic analysis of reactions for their formation were established. Accordingly the data of thermodynamic analysis of temperature conditions for obtaining double superphosphate, the most formation of monosubstituted phosphates of copper, zinc and cobalt, and possibility of formation disubstituted of copper phosphates.

Towards a highly-controllable synthesis of copper oxide nanowires in radio-frequency reactive plasma: fast saturation at the targeted size

Nanoscale copper oxide is a material in high demand, playing a pivotal role in many nanostructure-based emerging applications. Some unique electrical and mechanical properties of these new generation nanostructures are that they are potentially able to boost the characteristics of sophisticated modern electronic devices. Nevertheless, a nontrivial technique commonly used for the synthesis of CuO/CuO2 nanostructures (particularly in nanowires) as well as very complicated growth and nucleation mechanisms, are their stumbling blocks, significantly hindering the occupation of a relevant application niche. In this paper, we theoretically and experimentally demonstrate that the ultramodern radio-frequency plasma-based fabrication technique ensures avoiding highly unfavourable, uncontrollable growth intrinsic to the commonly used thermal oxidation method. Moreover, it enables switching the process to a rapid, target-saturating mode leading to fast, highly controllable nucleation and growth of thin, long, densely packed, highly crystalline copper oxide nanostructures directly on the copper surface, without involving any additional precursors and catalysts in the process. Multiscale numerical simulations reveal the basic mechanisms behind the target-saturating growth mode and the key control factors enabling highly predictable synthesis of dense oxide nanostructures of pre-determined size and surface density.

Synthesis and Validation of a Cu Meta-Based Wideband Microwave Absorber on an Antenna Array

Meta copper (Cu) material called nanotwin crystalline copper metal (C2101, Kopu Tharma Loham) fabricated on the basis of ancient Indian metallurgical techniques has been originally used here as an absorbing material. The research attempted here is to explore the electromagnetic properties experimentally over a wide range of frequency covering X, Ku, K and Ka bands. The dielectric constant and loss tangent of Cu meta material are high in the X range making it a good candidate for the successful design of an absorber. Along with that, the melting point of Cu meta is also increased to 1135°C which is otherwise 1085°C as per international copper standards, hence making the absorber thermally stable. The particle size of Cu meta material, when measured with the x-ray diffraction method, is decreased from 50 μm to 100 nm, placing it in a nanomaterial category. An absorption bandwidth of 35.58 GHz is obtained, ranging from 1 GHz to 36.58 GHz. After testing, the absorber is finally integrated with a two-element rectangular patch array for substantial applicability. The radiation pattern plot shows a remarkable reduction in side lobe level of the array from 3.737 dB to 1.158 dB after placing the Cu meta material absorber. The beam width narrows down from 70° to 44° with a slight increase in the amplitude of the major lobe from 5.494 dB to 6.341 dB while retaining the pattern symmetry.

Toward scalable perovskite‐based multijunction solar modules

AbstractPerovskite‐based multijunction solar cells can potentially overcome the power conversion efficiency (PCE) limits of established solar cell technologies. The technology combines high‐efficiency perovskite top solar cells with crystalline silicon (c‐Si) and copper indium gallium diselenide (CIGS) single‐junction solar cells enabling a more efficient harnessing of solar energy. In this work, we present high‐efficiency and scalable perovskite‐CIGS and perovskite‐Si multijunction solar modules in a four‐terminal configuration. We design the multijunction solar modules for minimal optical losses through careful optical engineering. In addition to optimized light coupling, the solar modules are fabricated in a scalable device design. Starting from lab‐scale cells of 0.13 cm2, we scale up the multijunction devices by two orders of magnitude to 16 cm2 and investigate the various losses affecting the PCE of large‐area multijunction solar modules, thus providing valuable insights into scalability of the technology. The champion perovskite‐CIGS and perovskite‐Si multijunction solar modules exhibit higher PCE than the stand‐alone devices on sizes up 16 cm2, paving the way for high‐effiency perovskite‐based multijunction photovoltaics. This work brings to forth relevant upscaling aspects of perovskite‐based multijunction solar cell technology, which is a key milestone in the road to commercial feasibility of the perovskite‐based multijunction solar cell technology.

Preparing copper doped carbon nitride from melamine templated crystalline copper chloride for Fenton-like catalysis

Heterogeneous catalysts prepared by doping metal ions in g-C3N4 have been demonstrated as a type of promising alternative to the traditional homogeneous Fenton catalysts. The metal–Nx active sites of metal doped g-C3N4 composites are responsible for their enhanced catalytic activity. However, it is very difficult to achieve high content of metal–Nx species through pyrolyzing the physical mixtures of metal salts and g-C3N4 or melamine. In this work, copper doped g-C3N4 composites were synthesized by pyrolyzing a melamine templated crystalline copper chloride [H2mela]2[CuCl5]Cl. High content of Cu–Nx species were formed in these Cu-g-C3N4 composites. Compared with the catalysts prepared by pyrolyzing the physical mixtures of CuCl2 and g-C3N4/mela, the Cu-g-C3N4 composites exhibited enhanced catalytic activities for the degradation of RhB, MO, and MB. This work suggests that crystalline metal chlorides contained melamine ligands could be employed as efficient precursors for synthesizing metal doped g-C3N4 composites with high content of metal-Nx species.

Crystal plasticity finite element simulation and experiment investigation of nanoscratching of single crystalline copper

Mechanical properties of crystalline materials strongly correlate with deformation behaviour at the grain level. In the present work, we establish a 3D crystal plasticity finite element model of nanoscratching of single crystalline copper using a Berkovich probe, which is capable of addressing the crystallography influence. In particular, nanoindentation experiments and high resolution electron back-scatter diffraction characterization are jointly carried out to precisely calibrate parameters used in the crystal plasticity finite element model. Subsequent finite element simulations of nanoscratching are performed to reveal fundamental deformation behaviour of single crystalline copper in terms of mechanical response and surface pile-up topography, as well as their dependence on crystallographic orientation. Furthermore, nanoscratching experiments with the same parameters used in the finite element simulations are carried out, the results of which are further compared with predication results by the finite element simulations. Simulation data and experimental results jointly demonstrate the strong anisotropic characteristics of single crystalline copper under nanoscratching, due to the crystallographic orientation dependent coupled effects of intrinsic dislocation slip and extrinsic discrete stress distribution by probe geometry.

Laser nature dependence on enhancement of optical and thermal properties of copper oxide nanofluids

The miniaturization of electronic devices and increasing industrial energy consumption demands the efficient cooling systems/cooling fluids. The state of the art refrigerants known as nanofluids are the promising coolant fluids. The nanofluids are expected to exhibit high thermal conductivity depending upon the nature of fluid, dispersed nanoparticles and stability of the dispersion. In this study, Copper and Copper oxide nanofluids (Cu/CuO-NFs) are synthesized via Laser ablation synthesis in Liquid (LAL) method. A Continuous Wave (CW) laser and a nanosecond pulsed laser were used for synthesis of Cu/CuO-NFs in deionized water; CW laser was employed first time for synthesis of Cu/CuO-NFs. Highly pure and crystalline copper oxide nanoparticles were prepared with average size of 25 nm and 10 nm exhibiting 29% and 41% enhancement in thermal conductivity synthesized by CW and pulsed laser, respectively. Moreover, the synthesized Cu/CuO-NPs exhibited the broad band gap as compared to the bulk material. Therefore, the synthesized nanofluids are the potential candidate for efficient heat transfer application.