Covellite CuS Research Articles

Structural and electronic properties of the two-dimensional superconductor CuS with 113-valent copper

We present first-principles calculations of the structural and electronic properties of the CuS covellite material. The symmetry-lowering structural transition is well reproduced. However, the microscopic origin of the transition is unclear. The calculations firmly establish that the previously controversial Cu valency in this compound is 1.33. We also argue that recently reported high-temperature superconductivity (HTSC) in CuS is unlikely to occur in the stoichiometric defect-free material, since the determined Cu valency is too close to 1 to ensure proximity to a Mott-Hubbard state and superexchange spin fluctuations of considerable strength. On the other hand, one can imagine a related system with more holes per Cu in the same structural motif (e.g., due to defects or O impurities), in which case the combination of superexchange and a Fermi surface enlarged compared to that of CuS may lead to unconventional superconductivity, as in HTSC cuprates, but, unlike them, of an $f$-wave symmetry.

Growth of single-crystal copper sulfide thin films via electrodeposition in ionic liquid media for lithium ion batteries

By exploiting the ability of ionic liquids to solubilize molecular sulfur at the melting point, we report the electrodeposition of CuS in an [EMIm]TFSI (1-ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide) electrolytic bath containing Cu(TFSI)2 salt and elemental sulfur. Single-crystal and preferentially oriented covellite CuS thin films with flake morphology have been successfully obtained. Li/CuS coin cells using the deposits after carbon coating as the positive electrode show a discharge capacity of 350 mA h g−1 with capacity retention of 54.4% after 20 cycles.

Low temperature growth of CuS nanoparticles by reflux condensation method

We report a facile, low-temperature soft solution route to synthesize copper sulfide (CuS) nanomaterials with different morphologies by reflux condensation method. CuS nanomaterials were synthesized without the assistance of additional surfactant or templates, and the influence of key synthetic parameters namely solvent medium and sulfur source on the final structure of CuS was comprehensively investigated. XRD pattern of the synthesized products revealed the formation of hexagonal structure of covellite CuS. SEM analysis showed that the CuS products synthesized in water were ball-like microspheres and the products prepared in ethanol were spherical shaped CuS nanocrystals, but those synthesized in ethylenediamine were flower-like CuS hierarchical network consisting of self-assembled nanoflakes as primary building units. DRS exhibited the characteristics broadband absorption of CuS in near-IR region. The optical band gap of the CuS nanocrystals was in the range between 2.35 eV and 2.81 eV, exhibiting considerable blue shift due to quantum size effects. Electrical resistivity measurements confirmed the semiconducting nature of CuS. On the basis of experimental results, the plausible formation mechanism of different CuS nanostructures was put forward and discussed briefly.

Large-scale synthesis of CuS hexaplates in mixed solvents using a solvothermal method

Large-scale covellite CuS hexaplates were successfully synthesized by the 200 °C solvothermal reactions of CuCl 2.2H 2O and (NH 4) 2S in C 2H 5OH–H 2O mixed solvents containing HCOOH as a pH stabilizer, including different amounts and molecular weights (MWs) of polyethylene glycol (PEG). By using XRD and SAED, CuS (hcp) was detected. XRD peaks of the product, synthesized in a solution containing 5 g PEG6000 and 1.5 ml HCOOH for 5 h, are in accordance with those of the simulation and database. The (110) peak shows the preferential growth, corresponding to the hexaplates, characterized using SEM, TEM and HRTEM. CuS hexaplates with the (100) and (010) lattice planes at an angle of 120° were detected on the flat surface, and the (002) lattice plane on the edge. UV–vis absorption edge was detected at 610 nm (2.03 eV), and the PL emission at 361 nm (3.43 eV). Phase and morphology formations were also explained according to the experimental results.

From Self-Assembled Cu(II) Coordination Polymer to Shape-Controlled CuS Nanocrystals

A hydrogen-bonded 1D coordination polymer, {[Cu(HSglu)(H2O)]·H2O}n, 1, has been used as a precursor as well as a sacrificial template to synthesize covellite CuS nanomaterials. A remarkable correla...

Formation of CuS submicrotubes with quadrate cross section

CuS submicrotubes with quadrate cross section were synthesized by two simple steps: (i) preparation of copper–thiourea (Tu) complex; and (ii) subsequent reaction of the as-prepared complex with Na 2S solution. Copper–Tu complex was characterized using X-ray diffraction (XRD), thermal gravimetric (TG) and Fourier transform infrared (FT-IR) measurements. CuS submicrotubes were found to be constructed by covellite CuS with a hexagonal phase. The possible mechanism for the formation of quadrate CuS submicrotubes was proposed. This simple method may be applied to synthesize other inorganic materials with hollow structure.

A micro-interface route to CuS superstructure composed of intersectional nanoplates

Copper sulfide (CuS) superstructure composed of intersectional nanoplates was synthesized by a micro-interface reaction method. The covellite CuS nanocrystals were formed by the growth of hexagonal plates along the diagonal directions of the basal plate with an average edge length of ca. 350 nm and thickness of ca. 20 nm. X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and high-resolution TEM (HRTEM) were used to characterize the CuS. The possible mechanism for the formation of the interesting CuS nanostructure on the 1,2-dichlorobenzene-ethylene glycol micro-interface was discussed.

Asynchronous-pulse ultrasonic spray pyrolysis deposition of Cu xS (x=1, 2) thin films

Nanocrystalline Cu xS (x=1, 2) thin films were deposited by asynchronous-pulse ultrasonic spray pyrolysis (APUSP) technique on glass from CuCl 2 and thiourea at relatively low temperature without any complexing agent. The deposited films chemically close to CuS were found to be polycrystalline phases, while the Cu 2S films were a mixture of amorphous and polycrystalline as well. The crystalline phase of particles was highly depended on the molar ratio of thiourea to CuCl 2 and the pyrolysis temperature. The growth of Cu xS thin films was controlled successfully by the improved APUSP method. Characterization of the films has been carried out using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. XRD and XPS analysis showed stoichiometric Cu xS (covellite CuS and chalcolite Cu 2S). Raman shifts of the films were measured at 474 cm −1 (CuS) and 472 cm −1 (Cu 2S).

Nature and origin of multicomponent aerial emissions of the copper–nickel smelter complex

The Severonickel Smelter Complex as well as other big nickel–copper smelter plants are the source of metallurgical dust emissions, enriched with toxic elements Ni, Cu, Pb, Zn and As. The phase composition of typical metallurgy dust is described as pentlandite (Ni,Fe) 9S 8, pyrrhotite Fe 7S 8(Ni x ), chalcopyrite CuFeS 2, chalcosite Cu 2S, covellite CuS, cuprite Cu 2O, tenorite CuO, and metal copper and nickel. The fine dust fractions are enriched by lead, zinc and arsenic oxides. The obtained data can be turned to account when conducting the investigations of heavy metal behaviour in nature media, in particular soils.

Conductivity anisotropy and structural phase transition in Covellite CuS

Covellite CuS consists of alternating layers with compositions CuS and Cu 2S 2. We examine the anisotropy of the electrical conductivity and the origin of the structural phase transition in CuS by performing extended Hückel tight-binding band electronic structure calculations. Our study shows that CuS is a three-dimensional metal, but its conductivity should be much greater along the directions perpendicular than parallel to the c-axis. The partially empty valence bands of CuS have strong contributions from the sulfur 3p orbitals of the Cu 2S 2 layers, so that the oxidation state of CuS is better described by (Cu +) 3(S 2−)(S 2− than by (Cu +) 3(S −)(S 2 2−). The structural phase transition of CuS is not driven by Fermi surface instability. A probable cause for this phase transition cannot be the bonding interactions between the Cu + ions but the van der Waals interactions of the S…S contacts between the CuS and Cu 2S 2 layers.

The crystal structure of covellite CuS under high pressure up to 33 kbar

Article The crystal structure of covellite CuS under high pressure up to 33 kbar was published on December 1, 1985 in the journal Zeitschrift für Kristallographie - Crystalline Materials (volume 173, issue 1-4).

The crystal structure of covellite CuS under high pressure up to 33kbar

The crystal structure of covellite has been studied under pressure up to 33 kbar based on single-crystal diffraction intensities collected with a four-circle diffractometer. The contraction of the unit cell takes place in such a way that the axial ratio e/a is kept nearIy constant, the cell volume at 1 bar being reduced by about 5% at 33 kbar. With the contraction of the Cu - S bonds the sulfur-sulfur bond of the S2 group shows a trend of lengthening in a way similar to the relation between S - S and M - S bonds in the compounds MS2 (M = Cu, Ni, Co, Fe) having the pyrite structure type.

The crystal structures of Cu1•8Se, Cu3Se2, α- and γCuSe, CuSe2, and CuSe2II

The crystal structures of a number of copper selenides have been re-examined using X-ray powder diffraction intensity data. |F0| values for Cu1•8Se at room temperature (a = 5.765 Å) are satisfied by a model based on space group Fm3m with 4 Se atoms per unit cell on the fcc sites, 5.2 Cu atoms on the tetrahedral sites, and 2.0 Cu atoms on the trigonal sites in the Se sublattice. Cu3Se2 is tetragonal, [Formula: see text] a = 6.402, c = 4.279 Å, with Cu(1) in 2(a), Cu(2) in 4(e) with x = 0.147 ± 5, z = 0.781 ± 9, and Se in 4(e) with x = 0.272 ± 3, z = 0.264 ± 7. CuSe2 has the orthorhombic C18 marcasite structure, Pnnm, a = 5.005, b = 6.182, c = 3.740 Å, with Cu in 2(a), and Se in 4(g) with x = 0.184 ± 1, y = 0.385 ± 1. CuSe2II has the cubic C2 pyrite structure, Pa3, a = 6.116 Å, with Cu in 4(a), and Se in 8(c) with x = 0.3891 ± 5.Neither αCuSe nor γCuSe have the CuS covellite structure.These results are discussed in some detail.