Dehydration Of Cu Research Articles

In-situ fabrication of superhydrophobic surface on copper with excellent anti-icing and anti-corrosion properties

The accumulation of ice on electrical construction works not only leads to the reduced efficiency of power supply and heat exchangers, but also increases the energy losses and even brings about serious disasters. Therefore, it is essential to reduce or eliminate the issue of ice accumulation on metal constructions. Nowadays, superhydrophobic surfaces have received lots of attentions for their outstanding hydrophobicity. In this study, Cu(OH)2 nano grass was firstly in-situ constructed on copper surface via simple anodization, then superhydrophobic CuO nano needles were obtained after the dehydration of Cu(OH)2 and modification with fluoro-alkyl silanes. The results showed that when the anodic oxidation temperature was 20 °C and the current density was 2 mA·cm−2, nano-needle-like multistage micro-nano structures can be obtained. The as-prepared superhydrophobic surface showed the water contact angle as large as 162° and sliding angle lower to 4°. Additionally, the as-prepared superhydrophobic surface displayed outstanding anti-icing property, delaying icing substantially even under − 10 °C environment regardless of droplet volume and type. Moreover, it also revealed good anti-corrosion property with a corrosion current density of 2.2 × 10−8 Ω·cm2 and the corrosion resistance of 1.55 × 106 Ω·cm2 which is about three order of magnitudes than that of bare copper. We prospect that this easily prepared surface can provide a solution of anti-icing and anti-corrosion for electrical construction works and large-scale metals.

On Verdigris, Part III: Crystal Structure, Magnetic and Spectral Properties of Anhydrous Copper(II) Acetate, a Paddle Wheel Chain

Pure anhydrous Cu(CH3COO)2 was obtained both, by thermal dehydration of Cu(CH3COO)2·H2O and by drying a commercially purchased mixture of Cu(CH3COO)2·H2O and Cu(CH3COO)2 in a nitrogen atmosphere using P2O5 as drying agent. The crystal structure was solved ab initio from synchrotron X‐ray powder diffraction (XRPD) data at 150 °C and from laboratory XRPD data at ambient conditions and found to be isotypic to anhydrous chromium(II), molybdenum(II) and rhodium(II) acetate. Cu(CH3COO)2 crystallizes in space group P1 (no. 2) with lattice parameters of a = 5.1486(3) Å, b = 7.5856(6) Å, c = 8.2832(6) Å, α = 77.984(4)°, β = 75.911(8)°, γ = 84.256(6)° at ambient conditions. Cu2(CH3COO)4 paddle wheels with short (2.6 Å) Cu–Cu distances form chains in a direction, which is the main motif in the crystal structure. Due to their identical structural main motif Cu(CH3COO)2·H2O and Cu(CH3COO)2 exhibit a similar bluish‐green color, almost identical UV/Vis spectra and comparable magnetic properties. The temperature dependent magnetic susceptibility also indicates only weak inter‐dimer spin exchange between neighbouring Cu2(CH3COO)4 paddle wheels.

Facile preparation of diverse copper oxide nanostructures and their characterization

Copper oxide (CuO) nanostructures, such as nanoshuttles, nanodisks and nanoparticles are synthesized by simple hydrothermal and wet chemical methods. The CuO nanostructures are prepared by thermal dehydration of Cu(OH)2·H2O crystal hydrate without any additives. The CuO nanostructures are characterized by energy dispersive X-ray absorption spectroscopy (EDAS), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, UV-vis spectroscopy and X-ray diffraction (XRD) techniques. The SEM images show that diameter of CuO nanoshuttles ranges from 300–400 nm and length of ∼1 μm. The platelet-like porous CuO nanoparticles have thickness of 0.2–0.4 μm and width of 0.5–1.5 μm. The CuO nanodisks have diameter of 500–700 nm and thickness of 60–120 nm. The EDAS analysis confirms purity of CuO samples. The FTIR spectra of CuO nanostructures exhibit that the vibration peaks correspond to stretching vibrations of CuO bond.

Crystal structure of catena-poly[[chlorido-(4,4'-dimethyl-2,2'-bi-pyridine-κ(2) N,N')copper(II)]-μ-chlorido

The title compound, [CuCl2(C12H12N2)] n , was obtained via a DMSO-mediated dehydration of Cu(4,4'-dimethyl-2,2'-bi-pyridine)-copper(II)·0.25H2O. The central Cu(II) atom is coordinated in a distorted trigonal-bipyramidal geometry by two N atoms of a chelating 4,4'-dimethyl-2,2'-bi-pyridine ligand [average Cu-N = 2.03 (3) Å] and three Cl atoms, one terminal with a short Cu-Cl bond of 2.2506 (10) Å, and two symmetry-equivalent and bridging bonds. The bridging Cl atom links the Cu(II) ions into chains parallel to [001] via one medium and one long Cu-Cl bond [2.3320 (10) and 2.5623 (9) Å]. The structure displays both inter- and intra-molecular C-H⋯Cl hydrogen bonding.

The effects of X-ray irradiation and temperature on the formation and stability of chemical species on enargite surfaces during XPS

An investigation of the species present on the surface of natural enargite and the effects of X-ray radiation on the surface after electrochemical oxidation at pH 10 has been carried out using X-ray photoelectron spectroscopy. Surface species present on fractured and polished unoxidized enargite have been compared with those present on the polished surface after oxidation at pH 10. The effect of X-ray irradiation time as a function of temperature on the forms and intensities of the photoelectron signals from the enargite surface was studied. High binding energy (BE) components and shake-ups of the Cu 2p signals, characteristic of a copper (II) hydroxide surface layer, reduced in intensity with increasing X-ray exposure time. Associated changes in the relative concentrations of surface oxygen species were also observed. Comparing a surface exposed to X-rays at 35°C with that maintained at −135°C, temperature was shown to significantly influence the rate of change. The observed changes were evaluated in terms of a proposed two-stage mechanism involving the dehydration of Cu(OH) to CuO, followed by photoreduction of CuO to Cu2O. The photoreduction effects of X-ray irradiation should be significantly reduced by sample cooling for consistent analysis of the enargite surface using XPS.

Cosurfactant-mediated microemulsion to free-standing hierarchical CuO arrays on copper substrates as anodes for lithium-ion batteries

A cosurfactant-mediated microemulsion synthesis of free-standing CuO arrays with hierarchical micro-cog architectures on copper substrates has been successfully established. The CuO cog-array films directly employed as anode electrodes derive from thermal dehydration of Cu(OH)2 arrays grown from copper substrates in the presence of AOT–n-butanol–isooctane–water microemulsions. Introducing n-butanol as a cosurfactant into the ternary AOT–isooctane–water system increases the rigidity of the reverse micelles and it can be selectively adsorbed on particular crystal faces, leading to well-aligned arrays as well as enlarged aspect ratios with average heights of over 6 μm and diameters of 1–2 μm. This result sharply contrasts with the multilayer film of micro-cog particles with a shortened aspect ratio prepared in the absence of n-butanol. The CuO film electrodes of free-standing micro-cog-arrays exhibit excellent electrochemical performance, including a long cycling life (with capacity retention of 91.6% at 1 C over 300 cycles) and outstanding rate capability even at high current rates (about 466 and 418 mA h g−1 at high rates of 12 and 15 C) in lithium ion batteries.

Wire-like Bundle Arrays of Copper Hydroxide Prepared by the Electrochemical Anodization of Cu Foil

Nanostructured copper compounds were grown by electrochemical anodization of copper foil in aqueous NaOH under varying conditions including electrolyte concentration, reaction temperature, current density, and reaction time. Their morphology and atomic composition were investigated by using SEM, TEM, XRD, EDS and XPS. At the conditions ([NaOH] = 1 M, 20 °C, 2 mA cm -2 ), wire-like orthorhombic Cu(OH) 2 nanobundles with an average width of 100 - 300 nm and length of 10 μm were synthesized with the preferential [100] growth direction. Furthermore, when the concentration decreased to 0.5 M NaOH, the 1D nanobundle structure became narrower and longer without any change in compositions or crystalline structure. Side reaction pathways appeared to compete with the 1D nanostructure formation channels: the formation of CuO nanoleaves at 50 °C via the sequential dehydration ofCu(OH) 2 , CuO/Cu 2 O aggregates in 4 M NaOH, and Cu 2 O nanoparticles and CuO nanosheets at lower current density.

Preparation and characterization of Cu(OH) 2 and CuO nanowires by the coupling route of microemulsion with homogenous precipitation

Using CuSO 4 and NH 3⋅H 2O as raw materials, one-dimensional (1D) Cu(OH) 2 nanowires were prepared by the coupling route of microemulsion with homogenous precipitation. The morphology and structure of products were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results indicate that the as-prepared Cu(OH) 2 nanowires are of high purity and are single crystalline with orthorhombic structure. The diameter of Cu(OH) 2 nanowires ranges from 33 nm to 46 nm and the length ranges from 400 nm to 2000 nm. The effects of different conditions such as the molar ratio of water to surfactant ( ω ), reactant concentration and the aging time on the morphology and the size of the products were studied. 1D CuO nanowires could be simply obtained by the dehydration of Cu(OH) 2, while maintaining the wire-shaped architecture. The catalytic performances of CuO nanocrystals on the thermal decomposition of ammonium perchlorate (AP) were also studied.

Facile Synthesis of Leaf-like Cu(OH) 2 and Its Conversion into CuO with Nanopores

Leaf-like Cu(OH) 2 single crystals were synthesized via the controlled emulsion interface method using Span80 (sorbitan monooleate) as the stabilizer of the emulsion system. CuO products with nanopores could be simply obtained by the dehydration of Cu(OH) 2, while maintaining the strip-shaped architecture. The phase structures and morphologies were measured by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectra, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Experimental results showed that Cu(OH) 2 microleaves were single crystals and the growth direction seemed to be in [111] crystal plane of the orthorhombic Cu(OH) 2. The formation of the nanopores should be attributed to the water loss of the transformation from Cu(OH) 2 to CuO. The formation process of Cu(OH) 2 was investigated by taking TEM images at different stages of the reaction. The formed nanoparticles began to rearrange to form nanorods and microleaves possibly via edge-by-edge and side-by-side oriented-attachments because of the formation of larger crystals greatly reducing the interfacial energy. Besides, CuO microarchitectures exhibit blue shifts in UV-Vis spectra and possess larger band gaps compared with those of bulk crystals.

Fabrication of CuO Pricky Microspheres with Tunable Size by a Simple Solution Route

A simple aqueous solution route was introduced for the fabrication of CuO pricky microspheres (CPMs) using CuCl(2) x 2H(2)O, Na(2)(C(4)H(4)O(6)) x 3H(2)O and NaOH as starting materials. The CPMs were composed of compressed nanothorns exhibiting tapering feature with tip size of less than 10 nm, and the size of CPMs could be tuned from 100-200 nm to 4-6 microm. The effects of the molar ratios of tartrate anions and NaOH to Cu(2+) cations, reagent concentration, and reaction temperature on the products were investigated, showing that the morphology of CPMs was determined by the molar ratio of tartrate to Cu(2+) cations and the size was greatly affected by reagent concentration and the molar ratio of NaOH to Cu(2+) cations in the precursor solution. The fabrication of CPMs went through rapid nucleation of Cu(OH)(2), aggregation and in situ dehydration of Cu(OH)(2), oriented-aggregation-based growth, and normal crystal growth of CuO nanothorns. The nucleation and crystal growth were successfully separated by controlled releasing of Cu(2+) and OH(-) ions through the reversible reaction of Cu(2+) cations, OH(-), and C(4)H(4)O(6)(2-) anions.

Synthesis of Cu(OH)2 Nanowires at Aqueous−Organic Interfaces

Cu(OH)2 nanowires have been successfully synthesized at the organic−aqueous interface by the interaction of the copper−bis(2-ethylhexyl) phosphate complex in the organic layer with NaOH in aqueous layer. The nanowires have an average length of 4 μm and are several nanometers in width. CuO nanowires and short wiskers are conveniently prepared through dehydration of Cu(OH)2 at high concentrations of NaOH under ambient conditions. Transmission electron microscopy and X-ray diffraction techniques have been used to characterize the microstructures and morphologies of the nanowire materials.

Reaction of NO with copper ions in Cu(II)-exchanged ZSM-5 zeolite: electron spin resonance, electron spin echo modulation and Fourier transform infrared spectroscopy

Dehydration of Cu(II)-exchanged ZSM-5 and rehydration have been studied by electron spin resonance (ESR) and electron spin echo modulation (ESEM). The ESEM results indicate that Cu(II) is present in hydrated Cu-ZSM-5 as paramagnetic Cu(II)–OH − with five coordinated water molecules. Upon thermal dehydration, the ESR intensity decreases by about 85%, and it is suggested that Cu(I) and Cu(II)–O − are formed among other possible species. The remaining isolated paramagnetic Cu(II) is identified by ESR as three different species: I, II and III with g ‖ values of 2.314, 2.301 and 2.272, respectively. After NO adsorption onto dehydrated Cu-ZSM-5, NO interactions with Cu(I), Cu(II)–O − and Cu(II) have been studied by ESR and fourier transform infrared spectroscopy. It is suggested that Cu(II)–O − interacts with NO to form Cu(I)–(NO 2) and that further interaction with NO yields Cu(II)–(NO 2)(NO). Cu(I) is also suggested to react with one or two NO to form Cu(I)–NO and Cu(I)–(NO) 2 of which the latter further transforms to Cu(II)–(N 2O)O −. Among the three paramagnetic Cu(II) ions, only species III reacts with NO to form Cu(II)–NO; the other two Cu(II) species are inactive toward NO adsorption. A schematic mechanism based on these and earlier results is proposed for NO adsorption, interaction and transformation over Cu-ZSM-5.

Microcalorimetric Studies of the Interactions of Lysozyme with Immobilized Metal Ions: Effects of Ion, pH Value, and Salt Concentration

This study extends previous research on the interaction of biomaterials with immobilized Cu(II) by isothermal titration calorimetry (ITC) on Fe(III). The difference of the binding behavior of protein with that of the immobilized metal ions is also discussed. For the immobilized Fe(III), ITC results show that the adsorption enthalpy at a constant pH value decreased as the NaCl concentration increased and also decreased with the pH values at constant NaCl concentrations. The adsorption enthalpy become negative under higher pH values or higher salt concentrations indicating the adsorption process is partly driven by the enthalpy. The enthalpy of lysozyme with Fe(III) is higher than that with Cu(II) implying that the heat required for the dehydration of Cu(II) is lower than for the dehydration of Fe(III) and/or that the heat generated from the formation of the coordination with Cu(II) is higher than with Fe(III). In addition, the comparison of different immobilized metal ions corresponding to the equilibrium binding affinity suggests that the binding force of lysozyme with Cu(II) is higher than with Fe(III). This study presents the chemical differences between the binding affinity and the adsorption enthalpy of lysozyme interacting with the immobilized metal ions. The binding and thermodynamic data presented in this study elucidate the mechanism and process of lysozyme binding with immobilized metal ions. In addition, the thermodynamic characteristic functions provide valuable information enabling a more thorough understanding of protein adsorption at the immobilized metal ion affinity surface.

Irradiation Effects During XPS Studies of Cu(II) Activation of Zinc Sulphide

The surfaces of zinc sulphide particles after copper(II) activation at pH 9 have been studied by x-ray photoelectron spectroscopy. The influence of x-ray irradiation time on the forms and intensities of the photoelectron signals from zinc sulphide particles activated at various copper coverages was investigated. High binding energy components and satellites of the Cu 2p signals, characteristic of copper(II) hydroxide overlayers, reduced in intensity with increased x-ray exposure. An associated reduction in the concentration of surface oxygen was also observed. Differential charging analysis and curve fitting reveal the dehydration of Cu(OH) 2 to CuO, followed by photoreduction of CuO to Cu 2 O. No evidence was found for x-ray irradiation enhancement of continued Cu activation of or diffusion into ZnS.

Dehydration of Cu−Hectorite: Water Isotherm, XRD, and EPR Studies

Electron paramagnetic resonance (EPR) associated with adsorption gravimetry and X-ray diffraction (XRD) has been used simultaneously to study the dehydration process in a Cu2+−hectorite. The combin...

Structure and reactivity of copper (II) carboxylates I. Copper (II) dipicolinates

The crystal and molecular structures of a series of salts formed by copper (II) with dipicolinic acid were used to interpret the dehydration behavior. The morphology of single crystals dehydration of Cu(dipic)·2H 2O (monoclinic and triclinic symmetry), Cu(dipic)·3H 2O and Cu(dipic) (H 2dipic)· xH 2O was shown to be governed by the arrangement of water molecules along specific orientations.

The vibrational spectra of the copper(II) formates: Part IV. The thermal behaviour of Cu(HCOO) 2 · 4H 2O and Cu(HCOO) 2 · 2H 2O

Several modifications of Cu(HCOO) 2 exist and two, or possibly three, are characterized in the present study by means of Raman measurements. Upon the dehydration of Cu(HCOO) 2 · 4H 2O, monoclinic Cu(HCOO) 2 is formed in a topotactical reaction and a Raman study reveals that the environments around the copper and formate ions are very similar in the two compounds. No evidence can be found of the formation of the dihydrate by means of the dehydration of the tetrahydrate, even though DTA/TG measurements show that the dehydration process is complex and occurs in several steps. When monoclinic Cu(HCOO) 2 is further heated it transforms into orthorhombic Cu(HCOO) 2 below 100°C. The dehydration of the dihydrate results in the formation of a modification of Cu(HCOO) 2 which closely resembles the monoclinic modification but behaves differently upon further application of heat.

On the relationship between the structures of Cu(II) complexes and their chemical transformations

The experimental activation energies (E *) of dehydration of Cu(NH3)4(H2O)SO4, Cu(en)2(H2O)X2 (X=Cl−, Br−), Cu(en)(H2O)2SO4, Cu(py)2(H2O)2SO4, CuCl2 · 2H2O and M 2 CuCl4 · 2H2O (M I =NH4, K, Rb) were obtained from their non-isothermal thermogravimetric curves using the Coats-Redfern method. TheseE * values were compared with known data on the structures of the Cu(II) coordination polyhedra in the above complexes. No dependence of theE * values was found on either the central atom — released ligand bond length, or the number and lengths of the hydrogen bonds formed by the released water molecules. However, it was found that it is justified to seek some relationship between theE * values and the anisotropic temperature factors of the donor atoms of the ligands split off.

Thermoanalytical Studies on the Dehydration of Cu(OH) 2 and the Heating Changes of Cuppric Oxide

The dehydfation process of Cu(OH)2 under the atmosphere of CO2, . N2, air, and the thermal property of the dehydration material CuO were investigated in detail by means of DTA, DSC, X-ray diffractometry and specific surface area measurement.The following procecess was considered to occur during the thermal decomposition of Cu(OH)2 under 1 atm.(a) Cu(OH)2 ptCuO + H20 t 157eC aH=11.4-kc al. /. mAol(b) The cr y stallizatien ef the dehydration material CuO.200-1000C(c) 2Cuo aF==Cu20 + 1/202 t 1014C(d) c., o(s) pt Cu, O(L) 1176CThe particle size of the sample during the de. hydration process(a) was the minimum value 44A at 9A8%. dehydration and t. hen increased to 52 A at 100%. ndehydration. Further the particle size, fCuO I creased to 635Aat 950, C dg the crystallizati. n pr, cess(b).

AN ESR STUDY OF COPPER(II) COMPLEXES WITH β-ALANINE

Abstract A single crystal of bis(β-alaninato)copper(II) hexahydrate (Cu(β-ala)2·6H2O) was prepared and measured by ESR. As the dehydration of Cu(β-ala)2·6H2O from the surface of the crystal is well known, the behaviour of the dehydration by three different drying methods was studied by ESR and it was found that the change from the dx2−y2 ground-state to the dz2 ground-state takes place.