CuCl Crystals Research Articles

A Self-Disperse Copper-Based Catalyst Synthesized via a Dry Mixing Method for Acetylene Hydrochlorination

Traditional methods for synthesizing single-site catalysts are typically complicated and require special chemicals due to their tendency to agglomerate. In this study, we present a self-disperse copper-based catalyst synthesized via a dry mixing method for acetylene hydrochlorination. During the reaction, the copper precursor compounds, i.e., CuBr, and CuI, were converted to CuCl. Subsequently, the formed CuCl crystals underwent a significant structural transformation, leading to the formation of small clusters and Cu single sites. The catalytic activity of 5% CuCl + C prepared through the dry mixing method decreased from 93.7% to 92.9% after 100 h of reaction under the condition of GHSV (C2H2) = 60 mL·h−1·g−1. A comparison of the 5% CuCl + C with the 5% CuCl/C obtained by the impregnation method reveals that the catalytic stability of the former was higher than the one prepared by the conventional impregnation method. The exceptional catalytic performance can be attributed to the reaction-induced active sites being highly dispersed and the porous structure of activated carbon being maximally preserved, which was confirmed by HAADF-STEM, BET, TPR, and TG. The reaction-induced dispersion of CuCl on carbon provides a new strategy for preparing single-site catalysts for acetylene hydrochlorination.

Synthesis, crystal structure, thermal stability, and photovoltaic properties of organic-inorganic hybridized copper-based perovskite single crystals modulated by organics

Organic-inorganic hybridized perovskite have excellent photovoltaic properties, especially Pb-based organic-inorganic perovskite polycrystalline thin films based on Pb-based organic-inorganic perovskite have achieved high power conversion efficiency, but the polycrystalline materials have a large number of grain boundaries and defects, which are susceptible to the influence of water and oxygen, leading to structural degradation, poor stability, high toxicity and slow degradation, which are not friendly to the environment. Therefore, in this paper, two copper-based organic-inorganic hybrid perovskite single crystals (C6H9N2)2CuCl4 and (C6H18N2)2Cu2Cl8 were synthesized by using the method of organic modulation, and were investigated by single-crystal X-ray diffraction, powder X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, thermogravimetric analysis, and UV–vis diffuse reflectance spectroscopy. The samples were analyzed in detail for crystal structure, chemical groups, bond characterization, optical and thermal stability. The results show that (C6H9N2)2CuCl4 and (C6H18N2)2Cu2Cl8 single crystals belong to the C2/c space group of the monoclinic crystal system and the P-1 space group of the triclinic crystal system, respectively. The optical band gap of (C6H9N2)2CuCl4 is 2.45 eV, which is stable up to 179 °C, and that of (C6H18N2)2Cu2Cl8 is 2.47 eV, which is stable up to 163 °C. The thermal stability of the crystals can be regulated by changing the organic cation in the A-site, but the optical band gap of the crystals cannot be regulated significantly.

Influence of low energy X-ray radiation on the thermochromic properties of polymer microcomposites based on [HN2(C2H5)2]2CuCl4 crystals

Influence of low energy X-ray radiation on the thermochromic properties of polymer microcomposites based on [HN2(C2H5)2]2CuCl4 crystals

Quantum Size Effect in Three-Dimensional Microscopic Semiconductor Crystals

The exciton absorption spectrum of microscopic CuCl crystals grown in a transparent dielectric matrix has been studied. The size of the microscopic crystals was varied in a controlled manner from several tens of angstroms to hundreds of angstroms. There is a short-wave shift (of up to 0.1 eV) of the exciton absorption lines, caused by a quantum size effect.

Calculation of the phase state of the [N(CH3)4]2CUCL4 crystals

The calculation of the spatial changes of the amplitude and phase of the order parameter was performed in the Python environment with the use of the Skipy and JiTCODE libraries. In [N(CH3)4]2CuCl4 crystals, there is an incommensurate phase I1 at the small values of the magnitude of long-range interaction (T<0.6) and an incommensurate phase I2 at T≥1.0. This is the same incommensurate phase, although the behavior of the amplitude and phase functions in it is different under the different conditions mentioned above. At T = 0.6 ÷ 1.0, the coexistence of these two phases is observed which is manifested in the absence of anomalous changes of q during the transition from the sinusoidal mode of IC modulation to the soliton regime

UV pulsed irradiation effect on the exciton luminescence of CuCl nanocrystals in borate glass

Heat treatment conditions effect on the characteristics of the Z3-exciton resonant luminescence of CuCl nanocrystals in potassium-aluminaborate glass is studied. The observed patterns of luminescence buildup are explained by the participation of thermal effects in recombination processes. The size effect in the resonance emission of Z3-excitons at 80 K is confirmed. The inverse dependence of the defectiveness of CuCl crystals in glass on the luminescence buildup rate of Z3-excitons is established.

The effect of electrodeposition time on CuCl anodes from waste copper etchant

As one common industrial waste liquid, waste copper (Cu) etchant can seriously pollute the environment if it is unreasonably managed. Herein, tetrahedron-like copper (I) chloride (CuCl) crystals were extracted from waste copper etchant by way of facile electrodeposition, and the effect of the electrodeposition time on the lithium (Li)-storage capacity of the copper (I) chloride crystal was further investigated. The results showed that the copper (I) chloride crystal had a regular tetrahedral morphology, and the density of the regular tetrahedral particles gradually increased with the extension of the electrodeposition time from 5 to 15, 20 and 25 s. Correspondingly, the reversible lithium-storage capacity of the copper (I) chloride anode experienced an initial increase and a subsequent decrease. In detail, when cycling at 2 C for 250 cycles, the reversible discharge capacity of the copper (I) chloride anode increased from 187·3 mAh/g at 5 s to 284·5 mAh/g at 15 s and then decreased to 191·9 mAh/g at 20 s and to 125·3 mAh/g at 25 s, indicating that 15 s may be the most optimal electrodeposition time. Excessive copper (I) chloride particles may result in poor performance due to the poor inherent conductivity of copper (I) chloride. Such efforts would alleviate environmental pollution and facilitate the circular economy of wastes.

Thermochromic properties of nano- and microcomposites based on (NH2(C2H5)2)2CuCl4 crystals

Thermochromic properties of nano- and microcomposites based on (NH₂(C₂H₅)₂)₂CuCl₄ crystals

Tunable terahertz reflection spectrum based on zinc-blende structure crystals excited by ultrasonic

The tunable terahertz reflection spectrum of zinc-blende structure crystals (ZnSe, CuCl and InP), formed in the first bandgap, excited by ultrasonic is investigated in the present paper. Numerical simulation results show that, under the pressure of 0 GPa–100 GPa, the volume change of the crystal indicates that the zinc-blende structure crystals are suitable acousto-optic crystal. According to the optical phonon resonance dispersion, the frequency selective bandwidth of ZnSe, CuCl and InP crystal are 22.5 meV, 21.4 meV and 32.4 meV, respectively, indicating that the frequency selection range of InP crystal is wide. The transverse optical polariton is dis-propagating in the first bandgap and reflects. With the increase of ultrasonic frequency, the reflection peaks moves towards the restrahlen band, and the amplitude of the reflection spectrum decreases until it disappears. More transverse optical phonon combinations make the width of the reflection peak wider. The tunable terahertz reflection spectrum can be achieved by adjusting the ultrasonic frequency, a satisfactory condition for tunable selection and filtering in terahertz range.

Insights on the stability of cuprous chloride under high pressure: An equilibrium ab initio atomistic thermodynamics study

Density functional theory, in conjunction with ab initio atomistic thermodynamics, were used to investigate the stability of the low index cuprous chloride surfaces, and predict the morphology of CuCl nanocrystals under high pressures of chlorine. The rocksalt orientation of the lattice was adopted to resemble a CuCl crystal under high pressure. Under Cl-lean conditions, the defective CuCl(100)+Cl structure was found to be the most stable configuration among all surfaces investigated. Under Cl-rich conditions, a flawless, CuCl(111) surface with Cl-termination becomes the most stable configuration. It was shown that in a diluted chlorine environment, the CuCl in zinc blende structures are more stable than the CuCl in rocksalt configurations, while under a chlorine rich environment, the CuCl in rocksalt structures are more stable than the CuCl in zinc blende configurations. At low pressure of chlorine, it was found that the (100) facets are the most dominant to the Wulff construction, giving the crystal a coffin shape. As the pressure of chlorine increases, however, the involvement of the (111) facet increases giving the crystal a semi dodeca-hedron shape. At high pressure of chlorine, the major contributors to the Wulff construction were found to be the (111) facets, resulting in the formation of dodeca-hedron nanocrystals.

Observation of optical Stark effect between 1s - 2p exciton levels in CuCl single crystal

We measured the transient reflection spectra induced by infrared light for a CuCl single crystal using pump-probe spectroscopy. A Stark shift of the 1s exciton was observed using light with a near resonant energy between the 1s and 2p exciton levels. The amount of energy shift due to the Stark effect was obtained from the absorption spectra calculated using the Kramers–Kronig transform. We investigated the energy shift of 1s excitons with respect to the excitation density. This is the first published report on the Stark effect of 1s exciton associated with the internal energy levels of the excitons in CuCl crystal.

Magnetic and magneto-elastic couplings in the low-dimensional Heisenberg quantum magnet Cs2CuCl2Br2 with octahedral Cu coordination

Abstract In single crystals of the solid solution Cs2 CuCl 4 - x Br x ( 0 ⩽ x ⩽ 4 ), depending on the growth conditions, two structural modifications with a tetrahedral or an octahedral Cu environment can be realized. The border compounds (x = 0 and 4) with a tetrahedral Cu coordination have been recognized as model systems for quasi-2D frustrated anisotropic triangular quantum antiferromagnets. This holds true also for the newly discovered stoichiometric compounds with x = 1 and 2. In contrast, the systems exhibiting an octahedral Cu environment can be classified as quasi-2D ferromagnets characterized by ferromagnetic layers with a weak inter-layer coupling. Here we study the magnetic and magneto-elastic couplings for the low-dimensional Heisenberg quantum magnet Cs2CuCl2Br2 with octahedral Cu coordination. By applying magnetic susceptibility measurements under varying hydrostatic (He-gas) pressure, χ ( T , p ) , we determine the pressure dependence of the magnetic coupling constant ∂ J / ∂ p and estimate the magneto-elastic couplings ∂ J / ∂ ∊ v . These values are enhanced by almost one order of magnitude compared to Cs2CuCl2Br2 with tetrahedral Cu coordination.

Fabrication of superhydrophobic copper mesh by depositing CuCl for oil/water separation

A superhydrophobic/superoleophilic copper mesh with CuCl crystals for oil/water separation has been fabricated by immersing copper mesh in acidic CuCl2 solution and then grafting with 1-dodecanethiol. The mesh exhibits superhydrophobicity, with a water contact angle (WCA) of 151° and a water sliding angle of 4°. The mesh was used to separate various oil/water mixtures, including isooctane/water, petroleum ether/water, n-hexadecane/water, n-hexane/water and chloroform/water, with separation efficiencies over 95%. The mesh still kept separation efficiency above 99% and a WCA of 146° even after 20 separation cycles for chloroform/water mixture. In addition, the mesh could not only maintain high hydrophobicity after 50 g sand impact but also resist water droplets with different pH, indicating it has good mechanical and chemical durability.

Tribological and corrosion behaviors of bulk Cu[sbnd]W nanocomposites fabricated by mechanical alloying and warm pressing

Bulk Cu90W10 nanocomposites were fabricated by combination of mechanical alloying and warm pressing. The microstructure, mechanical properties, pin-on-disk dry sliding wear and corrosion behaviors were investigated. The W particles with average size of ∼112 nm are uniformly distributed in the Cu matrix and such nanostructured CuW alloys demonstrate excellent high temperature stability. After annealing at 600 °C for 1 h, the W particle size only increased ∼12% and hardness only decreased ∼5%. The plastic deformation region in Cu90W10 extends only about 3 μm below which the microstructure has recovered to the initial state and no chemical nanolayering was formed. Electrochemical corrosion tests show that the surface of Cu90W10 nanocomposite was severely damaged. The corrosion products were identified as predominantly gravel-like CuCl crystals with size of 0.5–4 μm and minor amount of very fine tungsten oxides nanoparticles with size of 50–80 nm.

In situRaman monitoring of single-walled carbon nanotube filling with copper chloride

<italic<In situ</italic< characterization of single-walled carbon nanotubes during their gas-phase filling with copper chloride (CuCl) was performed with Raman spectroscopy. The time dependence of positions and intensities of G, 2D, and radial breathing modes was investigated. It was demonstrated that the adsorption of copper chloride from gas phase on the external and internal surfaces of nanotubes leads to the Raman mode shifting. However, this effect is weaker than in case of formation of one-dimensional CuCl crystals inside nanotubes.

Phenomenological model of a sequence of phase transitions in (NR 4)2 MeX 4 crystals

A phenomenological model of a sequence of phase transitions in [N(C2H5)4]2CuCl4 crystals has been proposed. The model is constructed by methods of singularities of differentiable maps (the catastrophe theory). In this model, low-temperatures anomalies of thermal properties (entropy and heat capacity) are interpreted as isomorphic phase transitions or as a supercritical behavior on a thermodynamic path in the phase diagram near liquid-vapor end points.

Gel network incorporation into single crystals grown by decomplexation method

Crystallization in gel media has been occasionally found to result in single crystals with gel networks incorporated inside, extending the gel method with a long history for crystallization into a platform to design the internal composite structures of a crystal. The limited number of gel-incorporated crystals has inspired the investigation on how general gel incorporation is. Crystallization in gels through decomplexation has been widely used to grow crystals with extremely low water solubility, while whether the gel networks are incorporated inside these crystals has not been studied. In this work, crystals of AgCl, AgI and CuCl have been grown in both agarose gels and silica gels by decomplexation. The crystallographic structures of the crystals were identified by powder and/or single X-ray diffraction. The internal hybrid structures were studied by examining the residue materials after gentle etching and complete dissolution of the crystals. When grown from agarose gels containing self-assembled fibrous structures, gel networks were incorporated into single crystals of all the three compounds. In sharp contrast, the gel networks were pushed away when the crystals were grown in silica gels. The discrepancy between the crystals grown from agarose gels and those from silica gels is consistent with the effect of gel strength on gel incorporation. This work may help to harvest gel-incorporated crystals.

Optical properties of single‐walled carbon nanotubes filled with CuCl by gas‐phase technique

Single‐walled carbon nanotubes (SWCNTs) have unique electronic and optical properties, which are attractive in various applications. These properties can be further improved by functionalization. In this work, it is shown that filling nanotubes with CuCl leads to improvement of their electro‐conductive and optical transmission properties up to outstanding level. The improvement is due to the significant p‐type doping of the functionalized nanotubes. That leads to a huge increase in nanotubes charge carrier density and the considerable decrease of the nanotubes absorption via Pauli blocking. The functionalization was realized via a gas‐phase filling of SWCNTs with CuCl. We demonstrate the effect of huge doping on optical properties of nanotubes with different average diameters. The observed sufficient stability of the CuCl@SWCNT composite is proved to be due to the formation of quasi‐one‐dimensional (1D) CuCl crystal inside nanotubes. AC‐HRTEM image of 1D CuCl crystal formed inside SWCNT.

Study of exciton-polariton modes in nanocrystalline thin films of CuCl using reflectance spectroscopy

CuCl thin films grown on (100) Si by thermal evaporation are studied using reflectance spectroscopy. The reflectance spectra in the near UV spectral range close to the CuCl bandgap are modeled using a dielectric response function based on an exciton-polariton response with various models involving dead layers and reflected waves in the thin film. The exciton-polariton structure obtained is compared to other studies of bulk CuCl crystals. These different models are analyzed using a matrix-based approach and they yield theoretical spectra of reflected intensity. The fits provide parameter values which can be compared to bulk data known for CuCl and provide a non-destructive means of quantitative analysis of CuCl thin films. The best models are shown to match the experimental data quite well, with the closest fits produced when thin film front and rear interfaces are included. This model also accurately simulates the Fabry-Perot fringes present at energies lower than the Z3 free exciton position in CuCl (at 3.272 eV).

Electronic spectra and phase transitions in thin [N(CH3)4]2CuCl4 microcrystals

Optical absorption spectra in thin [N(CH3)4]2CuCl4 crystals in the thickness range 10 μm ≤ d < 100 μm have been studied. Strengthening of the crystal field has been found with a decrease in the [N(CH3)4]2CuCl4 crystal size. The reasons for absorption band shifts in the visible region depending on the [N(CH3)4]2CuCl4 crystal thickness and the manifestation of a size effect in crystals with an incommensurate superstructure are discussed.