CuCl Layer Research Articles

Investigation on the electrochemical evolution of the Cu-sn-Pb ternary alloy covered with CuCl in a simulated atmospheric environment

• The long-term electrochemical evolution of Cu-sn-Pb alloy with CuCl patina is studied for the first time. • The impedance value increases at 0 ∼ 3 h, decreases at 3 ∼ 7 h, and recovers after 7 h during EIS monitoring. • The fluctuation of impedance value is related to the conversion of CuCl to Cu 2 O and the cycle of chloride ions. Nantokite (CuCl) layer induces severe corrosion of bronze by its active reactivity to copper alloy. To further understand its corrosion mechanism, this paper investigated the electrochemical evolution process of the Cu-S n-Pb ternary alloy covered with a CuCl layer by continuous electrochemical impedance spectroscopy (EIS) monitoring. And the EIS changing mechanism induced by dynamic Cl - circulation and the transformation of the CuCl were also discussed. The results showed that two extreme impedance value points, the 3rd and 7th hours, were observed during the evolution process of the CuCl layer within 48 h. The decrease of the impedance value at 0 ∼ 3 h was mainly affected by the reaction of CuCl hydrolysis forming a Cu 2 O film, while the increase of impedance value at 3 ∼ 7 h was affected by the reaction of copper attacked by chloride ion. After 7 h, the impedance value of the Cu-Sn-Pb alloys continued to increase due to the formation of a dense cuprous oxide layer and chloride ions migrating into solution.

Tunable electronic and optical properties of new two-dimensional CuCl/GaSe van der Waals heterostructures with the potential for photocatalysis applications

The construction of a heterojunction photocatalyst can enhance the absorption of visible light and reduce the recombination of electrons and holes, which greatly improves the photocatalytic performance, which is also a current research hotspot in the energy field. In this paper, the first-principles calculation method is used to systematically study the electronic structure and photocatalytic mechanism of the new CuCl/GaSe van der Waals (vdW) heterojunction. The main research contents are summarized as follows: CuCl/GaSe vdW heterojunction is a direct band gap semiconductor material with a lattice mismatch rate of less than 1.5%, and a stable structure. The band gap of the heterojunction is 1.143 e V, which corresponds to a wider visible light absorption range. And it shows direct energy band alignment. The photo-generated holes are transferred from the GaSe layer to the CuCl layer, while the electrons are on the contrary, indicating that the electrons and holes are well separated in space. All these indicate that the CuCl/GaSe vdW heterojunction has good photocatalytic performance and is a new type of photocatalytic material with excellent performance.

Fabrication of cuprous chloride films on copper substrate by chemical bath deposition

Polycrystalline CuCl films were fabricated by chemical bath deposition (CBD) on a Cu substrate at a low solution temperature of 90°C.Continuous CuCl films were prepared using the copper (II) chloride (CuCl2) compound as the precursor for both the Cu2+ and Cl− sources, together with repeated HCl dip treatments. An HCl dip pretreatment of the substrate favored the nucleation of CuCl crystallites. Further, interrupting the film deposition and including an HCl dip treatment of the film growth surface facilitated the deposition of a full-coverage CuCl film.A dual beam (FIB/SEM) system with energy dispersive spectrometry facilities attached revealed a homogeneous CuCl layer with a flat-top surface and an average thickness of about 1μm. Both the excitonic and biexcitonic emission lines were well-resolved in the 6.4K photoluminescence spectra. In particular, the free exciton emission line was observable at room temperature, indicating the good quality of the CuCl films prepared by CBD.

Spin-Singlet Ground State of Two-Dimensional Quantum Spin Antiferromagnet (CuCl)Ca2Nb3O10

We report structural and magnetic properties of the triple-layered perovskite (CuCl)Ca2Nb3O10 with a spin-1/2 CuCl layer, investigated by transmission electron microscopy, magnetic susceptibility, high-field magnetization, specific heat, µSR, and inelastic neutron scattering measurements. The results show that (CuCl)Ca2Nb3O10 has a spin-singlet ground state with a gap of Δ/kB = 11 K. The observation of a 2 × 2 superstructure suggests a coherent distortion of the CuCl square lattice as in the double-layered (CuCl)LaNb2O7 with Δ/kB = 14 K. The low-temperature magnetization exhibits a jump to saturation above the critical field of Hc = 7.8 T, in marked contrast to the case of (CuCl)LaNb2O7, where the magnetization slowly increases above Hc. The observed magnetic properties are discussed in terms of the ferromagnetic Shastry–Sutherland model.

Generation of entangled-photon pairs from biexcitons in CuCl thin films: Nano-to-bulk crossover regime

We have constructed a theoretical framework of the biexciton-resonant hyperparametric scattering for the pursuit of high-power and high-quality generation of entangled photon pairs. Our framework is applicable to nano-to-bulk crossover regime where the center-of-mass motion of excitons and biexcitons is confined. Material surroundings and the polarization correlation of generated photons can be considered. We have analyzed the entangled-photon generation from CuCl film, by which ultraviolet entangled-photon pairs are generated, and from dielectric microcavity embedding a CuCl layer. We have revealed that in the nano-to-bulk crossover regime we generally get a high performance from the viewpoint of statistical accuracy, and the generation efficiency can be enhanced by the optical cavity with maintaining the high performance. The nano-to-bulk crossover regime has a variety of degrees of freedom to tune the entangled-photon generation, and the scattering spectra explicitly reflect quantized exciton-photon coupled modes in the finite structure.

Structural phase transition and magnetic properties of layered organic–inorganic hybrid compounds: p-Haloanilinium tetrachlorocuparate(II)

Compounds of the general formula A 2CuCl 4, (where A = 4-fluoroanilinium ( 1) and 4-chloroanilinium ( 2)) were prepared, structurally characterized and their thermal and magnetic properties studied. These compounds have a layered structure, distorted perovskite, where layers of CuCl 4 2− are sandwiched between a 4-haloanilinium cation bilayer. A single crystal X-ray diffraction study on (4-fluoroanilinium) 2CuCl 4, ( 1), shows that it crystallizes in the monoclinic P2 1/ c space group with cell dimensions a = 15.5113(5) Å, b = 7.3788(2) Å, c = 7.0929(2) Å, β = 99.004(2)°, volume 801.81(4) Å 3 at 150 K. Compound 2, (4-chloroanilinium) 2CuCl 4, crystallizes isostructurally to 1 at RT, but at 150 K it adopts the Pccn space group. This structural transition for 2 is reversible, and has been observed using Differential Scanning Calorimetric (DSC) measurements. The dc-magnetic studies using a SQUID magnetometer suggest that both compounds are soft ferromagnets and show an onset of long range magnetic ordering below 9 K. The ac-susceptibility measurements confirm the presence of this ferromagnetic ordering in both the compounds.

ChemInform Abstract: The Anodic Dissolution of Copper in Hydrochloric Acid Solutions.

The electrodissolution of copper in hydrochloric acid solutions at the rotating ring-disk elec- trode was found to be controlled by both mass transfer and reaction in the apparent-Tafel region in HCl concentrations of between 0.1 and 1.0 M. The proposed mechanism describes the adsorption of CuCl, on the corroding copper surface and the diffusion of CuCl; from the copper surface. The reaction in the limiting-current region was found to be controlled by the diffusion of Cl- to the copper surface through a porous CuCl layer that forms on the surface. The thickness of this porous layer is dependent on the stirring conditions, and independent of the Cl- concentration. Cu'+ is also produced at the Cu surface during electrodissolution. A mechanism describing the formation of a porous film of CuCl on the surface, the diffusion of Cl- through this tilm and the formation of Cu*+ has been proposed.

Bis(4-fluoroanilinium) tetrachloridocuprate(II)

The crystal structure of the title compound, (C6H7FN)2[CuCl4], consists of parallel two-dimensional perovskite-type layers of corner-sharing CuCl6 octa­hedra. These are bonded together via N—H⋯Cl hydrogen bonds from the 4-fluoro­anilinium chains, which are almost perpendicular to the layers. The CuCl4 dianions have two short Cu—Cl bonds [2.2657 (15) and 2.2884 (13) Å] and two longer bonds [2.8868 (15) Å], giving highly Jahn–Teller-distorted CuCl6 octa­hedra. The Cu atoms are situated on crystallographic centers of inversion.

銅電解精製におけるワックスレスパーマネントカソードプロセスのラミネーション界面

The lamination interface generated by a power outage during the electrorefining of copper using a wax-less permanent-cathode was investigated to elucidate the formation mechanism of the interface. X-ray diffraction, X-ray photoelectron spectroscopic measurements and electrochemical quartz crystal microbalance measurements revealed that the interface is composed mostly of CuCl (s) . Based on the thermodynamics of aqueous solution containing copper ions and chloride anions, it is considered that Cu+ ions are spontaneously generated through the reaction Cu + Cu2+ → 2Cu+ at the surface of the copper cathode, resulting in the deposition of insoluble CuCl (s) . Circulation of electrolyte during the power outage could suppress the accumulation of Cu+ ions in the vicinity of the cathode and minimize the formation of CuCl (s) layer, which makes the lamination interface after recovery from the power outage.

Exciton polaritons in bulk CuCl microcavities grown by vacuum deposition

AbstractWe demonstrate the realization of cavity polariton states in bulk CuCl microcavities. The CuCl microcavities made from a bulk CuCl layer and distributed Bragg reflectors consisting of PbF2 and PbBr2 layers prepared by vacuum deposition. Angle‐resolved reflectance spectra show the strong coupling characteristics of the excitons and photon mode; namely, the energies of reflectance structures exhibit incident‐angle dependence accompanying with an anticrossing behaviour peculiar to the cavity polaritons. From the phenomenological analysis with a 3×3 Hamiltonian of the cavity‐polariton modes originating from the Z3 exciton, Z1,2 exciton, and cavity photon, it has been revealed that the vacuum Rabi splitting energies in the λ‐thick CuCl active layer are 97 meV and 162 meV for the Z3 and Z1,2 excitons, respectively. We also indicate the potential to control the Rabi‐splitting energy by changing the active layer thickness. Furthermore, the spectral profile of reflectance is reasonably explained by calculations based on a theory of non‐local linear optical response. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

The chemical passivation of copper in ammonia solutions containing chlorine ions

It was shown that the CuCl layers deposited on copper chemically and electrochemically from copper-ammonia solutions were different. The layer formed chemically was loose, and that formed on the anode, dense. During multilayer copper passivation, the chemically deposited CuCl layer interfered with the formation of electrochemical CuCl and Cu2O layers.

Characterization of the copper/electrolyte interface on two copper conductors under high voltage

The effect of a high applied voltage up to 30 V between two copper conductors is investigated in a 0.05 mol L −1 sodium chloride solution. It appears that the potential is mainly applied to the anode/electrolyte interface and that, after a fast decay, the overall current density reaches a constant value, which is independent of the applied potential. This “passive” behaviour is attributed to the formation of a copper(I) chloride layer at the surface of the anode that limits the dissolution rate of copper in the electrolyte. It is shown that electromigration of chloride ions trough the CuCl layer controls the overall anodic reaction.

Initiation of copper dissolution in sodium chloride electrolytes

Initial stages of copper activation in chloride-ion containing neutral aqueous solution were studied. The results point that activation of copper passivity is initiated once the potential exceeds the breakdown value, occurring with well-defined incubation period, similar to that of other passive metals in chloride environments. The effect of applied potential and Cl − ion concentration on the incubation period is presented. The results indicate that an incubation period for copper activation in chloride containing solutions can be associated with the formation of a two-dimensional CuCl layer on the metal surface. The incubation period is relatively long at negative potentials and it is decreases with a positive shift in the potential. At a certain potential, the incubation period is sharply decreased. The time-frame of incubation period is attributed to the formation rate of two-dimensional CuCl layer and its reduction rate. The formation of a stable salt film on the metal surface facilitates localized rapid dissolution of the copper.

Corrosion inhibition of aluminium–brass in 3.5% NaCl solution and sea water

Electrochemical characteristics of Al–brass are investigated in both 3.5% NaCl and sea water. At active potential, the alloy is dissolved directly or through an adsorbed metastable CuCl layer. At higher applied anodic potential, the active–passive transition leads to the formation of a thicker and more stable CuCl salt layer. With further increase in the anodic potential, the formation of CuO and/or Cu(OH)2 will take place. The inhibition of the corrosion process is studied by adding SDBS, DPh(EO)9, and LAPACl as anionic, nonionic, and cationic surfactants. It is found that the inhibition efficiency increases in the following order SDBS>LAPACl>DPh(EO)9, and increases with increasing their concentrations.

Closed-cycle HCl/H 2/Cl 2 energy storage and power generation system using a [formula omitted] catalyst

An energy storage system based on HCl-H 2-Cl 2 chemistry is described. When dry HCl gas is passed over a copper surface, H 2 is released and Cu is oxidized to CuCl. Subsequently, upon heating to high temperatures, the CuCl bed is decomposed back to Cu, releasing Cl 2. The release of H 2 from HCl on a Cu surface was studied as a function of temperature, flow rate, and specific surface area. The products H 2 and CuCl were measured between 400 and 600 K; temperature has only a small effect on the reaction rate, at most T 1 2 . The surface geometry and gas flow allowed several thousand gas-surface collisions per HCl molecule for complete conversion of HCl to H 2. The thickness of the CuCl layer is not the limiting factor in the reaction probability for layers less than a few thousand monolayers deep. Recovery of Cl 2 by the thermal decomposition of CuCl was examined as a function of temperature and pressure. Useful Cl 2 yields were found only for system pressures below ca. 10 torr, at temperatures above 700 K, and using a flow of inert gas to sweep out the product.

The pit morphology on copper in chloride- and sulphate-containing solutions

For a better of understanding of the behaviour of copper towards pitting germination in chloride- and/or sulphate-containing borate-buffered solutions and more precisely of the synergetic effect of these two aggressive ions, the morphology of the pits appearing in these solutions has been examined in association with analysis of corrosion products by X-ray diffraction and analysis by X-ray photo-electron spectroscopy (XPS) of the material surface in attacked and unattacked zones. Pits generated in chloride-containing solutions are topped by an atacamite cap and the surface is covered with a layer of CuCl, while in sulphate containing solutions, copper is denuded under the caps which have a duplex structure of copper hydroxide and brochantite. The mechanism of pitting is explained by successive substitutions of the oxygen ions of the initial duplex structure of the passive film (CuO and Cu 2O) by the aggressive ions. In chloride- and sulphate-containing solutions, pit morphology and the mechanism of pitting depend on the relative concentrations of both ions. For low concentrations of chloride, sulphate ions are responsible for pitting. For high concentrations of chloride, chloride ions are responsible for pitting. For medium concentrations of chloride, there is competition between the aggressiveness of the sulphate ions (destruction of the oxide layers) and inhibition by the chloride ions (formation of a CuCl layer). The pit morphology in this case is a characteristic of both ions.

Intermolecular Arrangements of p-Substituted Aniliniums in the Interlayer of Cupric Chloride

Abstract Crystal structures and magnetic properties of the layered pervoskite compounds, (p-X-C6H4NH3 +)2CuCl4 2-with X=CN (1), Cl(2), and NO2 (3), were studied. The compound 1 crystallizes in the triclinic P 1 space group. The structure consists of a CuCl layer and an organic bilayer in which the molecular axis of the cyanoanilinium is nearly perpendicular to the inorganic layer. At the middle of the organic bilayer, there is a layer of the CN group, in which the CN groups are arranged to cancel their electric dipoles. The compound 2 has a similar structure to that of 1. The crystal of 3 belongs to the orthorhombic Pbca space group, in which the structure also consists of an inorganic layer and an organic bilayer. The bilayer is formed by short contacts between the NO2 groups, which appear to incline the molecular axis of the nitroanilinium with respect to the normal to the CuCl layer. AC and DC magnetic susceptibility measurements were carried out on the three salts. Their behavior can be understood wit...

Optical studies in [formula omitted] epilayers: Fabry-Perot modes in the upper branch of the polariton

We report the observation of discrete modes in the upper branch of the exciton-polariton. In micrometer thick ZnSe epilayers grown on GaAs substrates by metal organic vapour phase epitaxy we have studied the evolution of the reflectivity spectra as a function of the thickness of the deposited ZnSe layers. For layer thickness in the range of a micron we observe reflectance oscillations that we interpret as due to Fabry-Perot modes in the upper branch of the polariton. This observation is possible due to the large exciton binding energy in ZnSe and the subsequent large energy extension of this branch. The amplitude of these oscillations and their energy splitting decrease with increasing thickness of the epilayer. They could no longer be observed for thickness larger than 4.5 μm. The effect is analyzed in the context of a semiclassical approach using a non-local description of the dielectric constant, combined with results previously obtained in thin layers of bulk CdSe and CuCl.

Role of alloying elements tin and aluminium in anodic behaviour of homogeneous copper based alloys in 3-5 wt-%NaCl solution

The anodic behaviour of homogeneous Cu-Sn and Cll-Al alloys in aqueous 3·5 wt-%NaCl solution has been investigated by potentiodynamic polarisation, cyclic voltammetry, and potentiostatic current-time experiments and compared with the behaviour of pure Cu. Specimens were subjected to various anodic potentials and subsequent analyses by scanning electron microscopy supplemented with energy dispersive spectroscopy. At active potentials, the alloys and the pure Cu either dissolve directly or through an adsorbed metastable CuCl layer by transport of CuCl; ions. The active-passive transition at higher applied anodic potential resulted in the formation of a thicker and more stable CuCl salt layer. Withfurther increases in anodic potential, the compact CuCl salt layer on the Cu-Sn alloys impedes the formation of CuO or Cu(OH)2, thus maintaining perfect passivity. In contrast, on pure Cu and Cu-Al oxide or hydroxide is formed just beneath a less compact CuCl layer and so provides imperfect passivation. This difference in anodic behaviour between the homogeneous Cu Sn and Cu Al alloys is discussed, with reference to the pure Cu specimen, in terms of the difference between the CuCl layers incorporated with more protective SnOHCl.H2O (or less protective AlCl or Al(OH)2Cl) and those CuCl layers which are undoped.

Role of alloying elements tin and aluminium in anodic behaviour of homogeneous copper based alloys in 3-5 wt-%NaCl solution

The anodic behaviour of homogeneous Cu-Sn and Cll-Al alloys in aqueous 3·5 wt-%NaCl solution has been investigated by potentiodynamic polarisation, cyclic voltammetry, and potentiostatic current-time experiments and compared with the behaviour of pure Cu. Specimens were subjected to various anodic potentials and subsequent analyses by scanning electron microscopy supplemented with energy dispersive spectroscopy. At active potentials, the alloys and the pure Cu either dissolve directly or through an adsorbed metastable CuCl layer by transport of CuCl; ions. The active-passive transition at higher applied anodic potential resulted in the formation of a thicker and more stable CuCl salt layer. Withfurther increases in anodic potential, the compact CuCl salt layer on the Cu-Sn alloys impedes the formation of CuO or Cu(OH)2, thus maintaining perfect passivity. In contrast, on pure Cu and Cu-Al oxide or hydroxide is formed just beneath a less compact CuCl layer and so provides imperfect passivation. This difference in anodic behaviour between the homogeneous Cu Sn and Cu Al alloys is discussed, with reference to the pure Cu specimen, in terms of the difference between the CuCl layers incorporated with more protective SnOHCl.H2O (or less protective AlCl or Al(OH)2Cl) and those CuCl layers which are undoped.