Showing papers on "Copper published in 2006"
TL;DR: A review of the literature on the aqueous reduction of CO2 to hydrocarbons at copper electrodes is provided in this article, covering the literature since the first report of the reaction in 1985.
1,238 citations
TL;DR: Results indicate a gender dependent feature of nanotoxicity andKidney, liver and spleen are found to be target organs of nano-copper particles.
845 citations
679 citations
15 Apr 2006
TL;DR: Volume 1 IRON Heme Proteins: Oxygen Storage and Oxygen Transport Proteinology Volume 2 IRON continued Non-Heme Protesins: Dinuclear Iron ProteINs Non-heme ProteINS: Iron Storage Non- Heme Protins: Iron Transport NICKEL MANGANESE COBALT MOLYBDENUM/TUNGSTEN COPPER Cupredoxins
Abstract: Volume 1 IRON Heme Proteins: Oxygen Storage and Oxygen Transport Proteins Heme Proteins: Cytochromes Heme Proteins: Cytochrome Peroxidases Heme Proteins: Cytochrome P-450 Heme Proteins: Oxidoreductases Non-Heme Proteins: Iron-Sulfur Clusters Non-Heme Proteins: Mononuclear Iron Proteins Volume 2 IRON continued Non-Heme Proteins: Dinuclear Iron Proteins Non-Heme Proteins: Iron Storage Non-Heme Proteins: Iron Transport NICKEL MANGANESE COBALT MOLYBDENUM/TUNGSTEN COPPER Cupredoxins (Type-1 Copper Proteins) Type-2 Copper Enzymes Binuclear Copper: Type-3 Copper Enzymes Binuclear Copper: CuA Copper Multicopper Enzymes Copper Storage and Transport VANADIUM.
648 citations
TL;DR: Copper and manganese SODs diverge greatly in sequence and also in the metal insertion process, with particular emphasis on how the metal is inserted in vivo into the active site of SOD.
476 citations
TL;DR: It is demonstrated that any metal, even gold, silver, and copper, can act as a catalyst for SWCNT synthesis in chemical vapor deposition (CVD), and carbon atoms can formSWCNTs in a self-assembling fashion on nanoparticles without the specific functions of iron-family elements.
Abstract: We demonstrate that any metal, even gold, silver, and copper, can act as a catalyst for SWCNT synthesis in chemical vapor deposition (CVD). Metal nanoparticles 3 nm or less in diameter, introduced into CVD ambience immediately after heat treatment at 800-950 degrees C in air, produce SWCNTs. The activation method is effective for copper and various noble metals as well as for iron-family elements. This implies that any metal particle may produce SWCNTs when its size becomes 1-3 nm. In other words, carbon atoms can form SWCNTs in a self-assembling fashion on nanoparticles without the specific functions of iron-family elements.
444 citations
TL;DR: Activated carbon prepared from Ceiba pentandra hulls for the removal of copper and cadmium from aqueous solutions has been studied and sorption kinetics have been analysed by Lagergren pseudo-first-order and pseudo-second-order kinetic models.
440 citations
TL;DR: The high selectivity of the CuI-beta-diketone catalyst for aliphatic amines represents a useful complement to the palladium-based methods and is highly tolerant of a number of reactive functional groups.
Abstract: Through the use of cyclic beta-diketones as supporting ligands, the copper-catalyzed coupling of aryl iodides with aliphatic amines occurs at room temperature in as little as 1 h. These high reaction rates allow for the coupling of a wide range of aryl and heteroaryl iodides at room temperature. This method is highly tolerant of a number of reactive functional groups, including -Br and aromatic -NH2 as well as phenolic and aliphatic -OH. The high selectivity of the CuI-beta-diketone catalyst for aliphatic amines represents a useful complement to the palladium-based methods.
394 citations
TL;DR: In this article, the temperature distribution and microstructural evolution of the friction stir welding of 6061 aluminum alloy (T6-temper condition) to copper are investigated. But the main focus of the work is on the microstructures of the weld.
372 citations
TL;DR: In this paper, the authors used polyvinyl chloride (PVC) matrix membranes containing neutral carrier porphyrin (A and B) ionophores for detecting copper in vegetable foliar and swimming pool water sample.
Abstract: Cu2+ selective sensors have been fabricated from polyvinyl chloride (PVC) matrix membranes containing neutral carrier porphyrin (A and B) ionophores. The addition of sodium tetraphenylborate and the plasticizer DOP has been found to substantially improve the performance of the sensors. The membranes of various compositions of the two porphyrins were investigated and it was found that the best performance was obtained for the membrane of composition B:PVC:NaTPB:DOP in the ratio 5:150:2:150. The sensor shows a linear potential response for Cu2+ over a wide concentration range 4.4 × 10−6 to 1.0 × 10−1 M with Nernstian compliance (29.3 mV decade−1 of activity) between pH 2.8 and 7.9 and a fast response time of ∼8 s. The potentiometric selectivity coefficient values as determined by fixed interference method indicate excellent selectivity for Cu2+ ions over interfering cations. The sensor exhibits adequate shelf life (∼4 months) with good reproducibility (standard deviation ± 0.2 mV). The sensor can also be used in partially non-aqueous media having up to 20% (v/v) methanol, ethanol or acetone content with no significant change in the value of slope or working concentration range. The sensor has been used in the potentiometric titration of Cu2+ with EDTA. The utility of the sensor has been tested by determining copper in vegetable foliar and swimming pool water sample successfully.
361 citations
TL;DR: This new synthesis process of SWNTs with a non-ferromagnetic catalyst brings more convenience to the study of magnetic properties ofSWNTs and gives more insight in structure-controlled synthesis of SW NTs.
Abstract: Metallic copper, which is normally considered as a contaminant in the growth of single-walled carbon nanotubes (SWNTs), was found to be an efficient catalyst to grow SWNTs under suitable conditions. It showed very high catalytic activity for the growth of both random SWNT networks and horizontally aligned SWNT arrays. Especially, high-quality SWNT arrays were obtained when monodispersed copper nanoparticles were used. The catalytic behavior of copper for the growth of SWNTs was discussed. The weaker interaction between the copper and silica surfaces plays an important role in the growth of high-quality horizontally aligned SWNT arrays. This new synthesis process of SWNTs with a non-ferromagnetic catalyst brings more convenience to the study of magnetic properties of SWNTs and gives more insight in structure-controlled synthesis of SWNTs.
TL;DR: The presence of light and heavy metal ions influenced the copper and cobalt uptake potential of crab shell and among several eluting agents, EDTA (pH 3.5, in HCl) performed well and also caused low biosorbent damage.
TL;DR: For the first time, an internal alkyne was successfully used in this copper-catalyzed cycloaddition reaction and DFT calculations allowed for the proposition of a new mechanistic pathway for disubstituted alkynes.
Abstract: A versatile and highly efficient catalyst for the Huisgen cycloaddition reaction has been developed. Previously isolated or in situ generated azides yielded 1,2,3-triazoles with differently substituted alkynes in the presence of a [(NHC)CuBr] complex (NHC = N-heterocyclic carbene). Extremely high reaction rates and excellent yields were obtained in all cases. This catalytic system fulfils the requirements of "click chemistry" with its mild and convenient conditions, notably in water or solvent free reactions and simple isolation with no purification step. Furthermore, for the first time, an internal alkyne was successfully used in this copper-catalyzed cycloaddition reaction. DFT calculations on this particular system allowed for the proposition of a new mechanistic pathway for disubstituted alkynes.
TL;DR: The sorption capacity of black liquor lignin is higher than many other adsorbents/carbons/biosorbents utilized for the removal of Cu( II) and Cd(II) from water/wastewater in single and multi-component systems.
TL;DR: In this paper, the melting enthalpy results of low-density polyethylene (LDPE) and linear low density polyethylenes (LLDPE), with different copper contents were prepared by melt mixing and the copper powder particle distributions were found to be relatively uniform at both low and high copper contents.
TL;DR: In this article, the kinetics and thermodynamics of copper and lead biosorption onto Aspergillus niger pretreated with NaOH were studied with respect to pH, temperature and initial metal ion concentration.
TL;DR: In this article, a method for X-ray photoelectron spectroscopy (XPS) analysis of core−shell nanoparticle composition and structure is developed to account for these factors quantitatively.
Abstract: Quantitative determination of oxide nanoparticle composition and structure by X-ray photoelectron spectroscopy (XPS) has proven difficult for metal oxides because of three factors: some oxide nanoparticles are prone to reduction in the XPS instrument under X-ray illumination in the ultrahigh vacuum (UHV) environment; the nanoparticle structure and integral nature of the XPS technique complicate the data analysis; and the composition is not constant during the finite sampling time required for the XPS experiment. In this report, a method for XPS analysis of core−shell nanoparticle composition and structure is developed to account for these factors quantitatively. The method is applied to characterize the copper(II) oxide (CuO) surface layer on copper(I) oxide (Cu2O) nanoparticles as well as the reduction kinetics of Cu2+ when held under X-ray irradiation in the XPS chamber. The XPS analysis is aided by the availability of copper oxide nanoparticles with a narrow size distribution. When corrected for the f...
TL;DR: Bulk pills of pressed carbon/copper nanoparticles displayed a highly pressure- and temperature-dependent electrical conductivity with sensitivity at least comparable to commercial materials and suggest the use of thin carbon/ copper nanocomposites as novel, low-cost sensor materials and offer a metal-based alternative to the currently used brittle oxidic spinels or perovskites.
Abstract: Copper nanoparticles with a mean carbon coating of about 1 nm were continuously produced at up to 10 g h−1 using a modified flame spray synthesis unit under highly reducing conditions. Raman spectroscopy and solid state 13C magic angle spinning nuclear magnetic resonance spectroscopy revealed that the thin carbon layer consisted of a sp2-hybridized carbon modification in the form of graphene stacks. The carbon layer protected the copper nanoparticles from oxidation in air. Bulk pills of pressed carbon/copper nanoparticles displayed a highly pressure- and temperature-dependent electrical conductivity with sensitivity at least comparable to commercial materials. These properties suggest the use of thin carbon/copper nanocomposites as novel, low-cost sensor materials and offer a metal-based alternative to the currently used brittle oxidic spinels or perovskites.
TL;DR: In this article, the metal-silica interaction and catalytic behavior of Cu-promoted Fe-Mn-K/SiO 2 catalysts were investigated by temperature-programmed reduction/desorption (TPR/TPD), differential thermogravimetric analysis, in situ diffuse reflectance infrared Fourier transform analysis, and Mossbauer spectroscopy.
TL;DR: Copper ions used in the metallation of CcO and Sod1 appear to be provided by a novel copper pool within the mitochondrial matrix.
TL;DR: The results demonstrate the technical viability of recovering copper using mechanical processing followed by an electrometallurgical technique and the copper obtained by electrowinning is above 98% in most of the tests.
TL;DR: The elemental concentrations of fish studied seemed to be close to the international standards and the highest trace element concentrations were obtained from pastırma, meat and sausage while the lowest value was observed in Trachurus trachurus (saurel).
TL;DR: In this paper, a model for the low temperature tensile response of copper polycrystals with grain sizes in the range of 2-50μm was proposed and the initial work hardening behavior was strongly grain size dependent and was considered to arise from a combination of kinematic and isotropic hardening due to dislocation-grain boundary interactions.
TL;DR: Waste beer yeast, a byproduct of brewing industry, was found to be a low cost and promising adsorbent for adsorbing copper and lead ions from wastewater and competitive biosorption of two metal ions was investigated in terms of sorption quantity.
TL;DR: In this article, a density-functional theory analysis of surface oxides is presented for low-temperature water-gas shift reaction and methanol oxidation reactions, and the results show that for the conditions typical of technical catalysis the bulk oxide is thermodynamically most stable.
Abstract: As a first step towards gaining microscopic understanding of copper-based catalysts, e.g., for the low-temperature water-gas shift reaction and methanol oxidation reactions, we present density-functional theory calculations investigating the chemisorption of oxygen, and the stability of surface oxides on $\mathrm{Cu}(111)$. We report atomic geometries, binding energies, and electronic properties for a wide range of oxygen coverages, in addition to the properties of bulk copper oxide. Through calculation of the Gibbs free energy, taking into account the temperature and pressure via the oxygen chemical potential, we obtain the $(p,T)$ phase diagram of $\mathrm{O}∕\mathrm{Cu}(111)$. Our results show that for the conditions typical of technical catalysis the bulk oxide is thermodynamically most stable. If, however, formation of this fully oxidized surface is prevented due to a kinetic hindering, a thin surface-oxide structure is found to be energetically preferred compared to chemisorbed oxygen on the surface, even at very low coverage. Similarly to the late $4d$ transition metals (Ru, Rh, Pd, Ag), sub-surface oxygen is found to be energetically unfavorable.
TL;DR: In this paper, the main characteristics related to the CLC process necessary to use the syngas obtained in an integrated gasification combined cycle (IGCC) power plant were analyzed.
Abstract: The combustion process integrated by coal gasification and chemical-looping combustion (CLC) could be used in power plants with a low energy penalty for CO2 capture. This work analyzes the main characteristics related to the CLC process necessary to use the syngas obtained in an integrated gasification combined cycle (IGCC) power plant. The kinetics of reduction with H2 and CO and oxidation with O2 of three high-reactivity oxygen carriers used in the CLC system have been determined in a thermogravimetric analyzer at atmospheric pressure. The iron- and nickel-based oxygen carriers were prepared by freeze-granulation, and the copper-based oxygen carrier was prepared by impregnation. The changing grain size model (CGSM) was used for the kinetic determination, assuming spherical grains for the freeze-granulated particles containing iron and nickel and a platelike geometry for the reacting surface of the copper-based impregnated particles. The dependence of the reaction rates on temperature was low, with the a...
TL;DR: Several biological and chemical leaching processes have emerged for overcoming the passivation of chalcopyrite in the last decade and a half as discussed by the authors, and a number of these processes are now entering commercial production or are approaching this status.
TL;DR: In this paper, the authors describe the materials aspects and electrical characteristics of W-(Cu/WO3)-Cu switching elements, which are compatible with back-end-of-line processing in CMOS integrated circuits where both tungsten and copper play a significant role.
Abstract: We describe the materials aspects and electrical characteristics of W-(Cu/WO3)-Cu switching elements. These materials are compatible with back-end-of-line processing in CMOS integrated circuits where both tungsten and copper already play a significant role. Devices based on Cu/WO3 solid electrolytes formed by photodiffusion of copper into tungsten oxide switch via the electrochemical formation of a conducting filament within the high resistance electrolyte film. They are able to switch reversibly between widely spaced nonvolatile resistance states at low voltage ( 125 degC). This difference in behavior was attributed to the observation that the copper tends to oxidize in the plasma-grown oxide whereas the copper in the deposited oxide exists in an unbound state and is, therefore, more able to participate in the switching process