Thermal Decomposition Of Copper Research Articles

Synthesis, Crystal Structure and Thermal Decomposition of Copper(II) and Manganese(II) Complexes Based on Bipyridine Dicarboxylate and 1,10-Phenanthroline

Synthesis, Crystal Structure and Thermal Decomposition of Copper(II) and Manganese(II) Complexes Based on Bipyridine Dicarboxylate and 1,10-Phenanthroline

Synthesis, Crystal Structure and Thermal decomposition of Copper(II) and Manganese(II) Complexes Based on Bipyridine Dicarboxylate and 1,10-Phenanthroline

Two novel transition metal complexes of the formulae [Cu(5,5′-bpdc)(phen)]n (1) and [Mn(6,6′-bpdc)(phen)(H2O)]·H2O (2) (where phen = 1,10-phenanthroline, 5,5′-H2bpdc = 2,2′-bipyridine-5,5′-dicarboxylic acid, 6,6′-H2bpdc = 2,2′-bipyridine-6,6′-dicarboxylic acid) were synthesized by hydrothermal reaction. The complexes were characterized by elemental analysis, X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetry and differential scanning calorimetry. The X-ray crystallographic investigation reveals that 1 is a coordination polymer, and its asymmetric structural units are connected by oxygen atoms in the carboxyl group of 5,5′-bpdc2– anion. 2 is a heptacoordination monomer complex with mono-capped trigonal prismatic configuration and its mononuclear molecules are connected by hydrogen bonds to form supramolecular structure. The result of fluorescence shows that 2 has fluorescent property.

Nonisothermal kinetic analysis of decomposition of CuCO3.Cu(OH)2 and 2ZnCO3.3Zn(OH)2

Thermal decomposition of copper (II) carbonate hydroxide (CCH), CuCO3.Cu(OH)2 and zinc hydroxide carbonate (ZHC), 2ZnCO3.3Zn(OH)2 is widely used for the synthesis of copper and zinc oxides. Kinetic modelling, identification of the rate-controlling step and change in thermodynamic properties of these decomposition reactions have not been reported adequately in the literature. In the present work, the kinetic behaviour of nonisothermal thermal decomposition of CuCO3.Cu(OH)2, and 2ZnCO3.3Zn(OH)2 has been investigated using thermogravimetric (TG) analysis, employing model-free iso-conversional as well as model-fitting methods. Mean apparent activation energy (Ea) values, estimated by various iso-conversional methods (KAS, Starink, FWO, Kissinger and Vyazovkin), were found to be in close agreement (104.9-111.2 kJ.mol-1 for CuCO3.Cu(OH)2 and 192.8-197.9 kJ.mol-1 for 2ZnCO3.3Zn(OH)2). Ea decreased significantly with an increase in conversion for CuCO3.Cu(OH)2, while it increased, peaked and then decreased with conversion for 2ZnCO3.3Zn(OH)2. It indicates that both decomposition reactions are not single-step. Avrami-Erofeev model of order 2.5 was found to explain the experimental TG data well for CuCO3.Cu(OH)2 decomposition, while 2ZnCO3.3Zn(OH)2 decomposition followed the chemical reaction model of order 1.75. Positive changes in the thermodynamic properties, enthalpy and Gibbs free energy for both samples showed that these endothermic decomposition reactions were not spontaneous. The difference between Ea and H was found to be low; 3.9-4.5 kJ.mol-1and 4.0-4.6 kJ.mol-1 for CuCO3.Cu(OH)2 and 2ZnCO3.3Zn(OH)2 respectively, indicating the reactions to be favourable. The thermodynamic properties, though not influenced by the iso-conversional method and the rate of heating, varied significantly with the conversion. FTIR analysis of the gases evolved from decomposition showed that dehydration started before the initiation of decarboxylation, followed by simultaneous progress of both these reactions for CuCO3.Cu(OH)2 and 2ZnCO3.3Zn(OH)2.

Genesis and Properties of MOx/CNTs (M = Ce, Cu, Mo) Catalysts for Aerobic Oxidative Desulfurization of a Model Diesel Fuel

Aerobic oxidative desulfurization of a model diesel fuel over MOx/CNTs catalysts (M = Ce, Cu, Mo) was studied to develop innovative technology for cleaning motor fuels to EURO-5 standard. It was shown that the thermal stability of catalysts improves in the following order of metal Сu < Сe < Мо. The disordering of the carbon matrix of support increases in the next row of M: Mo < Ce < Cu, which is accompanied by an increase in the specific surface area of the samples (40 → 105 m2/g). The forms of stabilization of the active component (CeO2, CuO/Cu2O/ Cu, or MoO3/MoO2) were revealed, indicating a partial reduction of the metal cations during the thermal decomposition of copper and molybdenum precursor compounds deposited on CNTs. In oxidative desulfurization of a model diesel fuel over MOx/CNTs catalysts at 150 °C the total conversion of dibenzothiophene increased in the next row of M: Се < Сu < Мо. It was found that at 150 °C over the optimum MoOx/CNTs catalyst the highest dibenzothiophene conversion 95–99% is observed. It was assumed that the high activity of MoOx/CNTs is associated with both the oxidizing ability and the tendency of MoOx to chemosorption of sulfur compounds.

Controlled Synthesis of CuS and Cu9S5 and Their Application in the Photocatalytic Mineralization of Tetracycline

Pure-phase Cu2−xS (x = 1, 0.2) nanoparticles have been synthesized by the thermal decomposition of copper(II) dithiocarbamate as a single-source precursor in oleylamine as a capping agent. The compositions of the Cu2−xS nanocrystals varied from CuS (covellite) through the mixture of phases (CuS and Cu7.2S4) to Cu9S5 (digenite) by simply varying the temperature of synthesis. The crystallinity and morphology of the copper sulfides were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), which showed pure phases at low (120 °C) and high (220 °C) temperatures and a mixture of phases at intermediate temperatures (150 and 180 °C). Covellite was of a spherical morphology, while digenite was rod shaped. The optical properties of these nanocrystals were characterized by UV−vis–NIR and photoluminescence spectroscopies. Both samples had very similar absorption spectra but distinguishable fluorescence properties and exhibited a blue shift in their band gap energies compared to bulk Cu2−xS. The pure phases were used as catalysts for the photocatalytic degradation of tetracycline (TC) under visible-light irradiation. The results demonstrated that the photocatalytic activity of the digenite phase exhibited higher catalytic degradation of 98.5% compared to the covellite phase, which showed 88% degradation within the 120 min reaction time using 80 mg of the catalysts. The higher degradation efficiency achieved with the digenite phase was attributed to its higher absorption of the visible light compared to covellite.

Metal salts as dopants for ZnO ceramics-thermogravimetry coupled with mass spectrometry studies

The paper presents results concerning thermal decomposition of copper II salts (acetylacetonate, acetate monohydrate and nitrate trihydrate) in synthetic air and argon flow. Thermogravimetry tests coupled with mass spectrometry were performed in temperature range of 25–1300 °C. The influence of salt addition on the rheological properties and sintering behaviour of ceramic samples was then investigated. The microstructure evolution based on light and scanning electron microscopies coupled with stereological methods was described. The performed investigations revealed not only the differences in thermal decomposition of examined salts but also differences in the phenomena related to the oxidation and reduction processes of copper products. The atmosphere has also influenced the mechanisms of salts decomposition as well as further changes in decomposition products. Moreover, the presence of ZnO powder has changed the thermal decomposition process of copper II acetylacetonate. The investigations showed that acetates and nitrates can be efficient in homogeneous distribution of small amounts of metal additives in the ZnO-based suspensions. Higher concentrations of these type of salts lead to the increase of viscosity due to the fact that acetates and nitrates increase the ionic strength in the slurry. On the other hand, acetylacetonates do not disturb the stability of the slurries. However, they are characterized by low water solubility and thus homogenous distribution of small amount of these dopants is more difficult. The addition of copper increased the grain size of the sintered ZnO samples. The copper was not segregated at grain boundaries in the form of oxide, it diffused into ZnO matrix.

Die-attach bonding for high temperature applications using thermal decomposition of copper(II) formate with polyethylene glycol

A copper paste based on commercial available copper(II) formate microparticles and polyethylene glycol as binder has been developed for bonding of semiconductor dies onto substrates below 300 °C. Thermal decomposition of copper(II) formate leads to the formation of copper nanoparticles, which are used to connect the chip electrically and mechanically to the substrate by a sinter process. The binder provides printability of the paste, protects the copper particles from oxidation and supports the formation of fine copper nanoparticles. Shear tests of the sintered interconnects return shear strength values of 60 MPa, offering a promising solution to form pure copper interconnects.

BAKIR ASETAT MONOHİDRATIN (Cu(CH3COO)2.H2O) TERMAL BOZUNMASINDAN BAKIR OKSİT (CuO) SENTEZİ

The synthesis of copper oxide (CuO) via the thermal decomposition of copper (II) acetate monohydrate (Cu(CH 3 COO) 2 .H 2 O) in air atmosphere was investigated at TG-DTG/DSC apparatus with the heating rate of 10°C min -1 under non-isothermal conditions from 25 to 900°C. It was seen from TG-DTG/DSC analyzes that the thermal decomposition process consists of three main steps (two mass-loss regions and a tiny mass-gain region). The obtained products at 200, 300, 400°C temperatures were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and Energy disperse spectroscopy (EDS) analysis. The XRD results show that the CuO nanoparticles having the monoclinic crystal structure. The SEM images showed that CuO nanoparticles were spherical in shape. The size of CuO nanoparticles decreased with an increase in annealing temperature.

水酸化銅 (II) の熱分解反応

水酸化銅 (II) の熱分解反応

Thermal decomposition of copper (II) acetylacetonate in supercritical carbon dioxide: In situ observation via UV–vis spectroscopy

The thermal decomposition of copper (II) acetylacetonate (Cu(II)(acac)2) in supercritical carbon dioxide (scCO2) was investigated via in situ UV–vis spectroscopy. Release of acetylacetone ligands from the central metal atom was observed as the initial step in the decomposition. The kinetics of the decomposition at 423–453K and 15–25MPa in scCO2 were studied. The decomposition reaction generally followed the first-order kinetics. The reaction rate was slightly increased with an increase in the pressure, due to changes in the scCO2 density. The activation energy of the decomposition was calculated as 60.3kJmol−1 at 15MPa, 56.3kJmol−1 at 20MPa and 52.4kJmol−1 at 25MPa, which are lower values than those observed in air and in vacuum. The pressure dependence of the activation energy of the decomposition reaction was clarified quantitatively for the first time, and revealed the energy conservation benefit of using scCO2 as a process solvent for a variety of metal/metal oxide deposition process of nanomaterials.

Solid–Solid Synthesis, Crystal Structure and Thermal Decomposition of Copper(II) Complex of 2-Picolinic Acid

The copper(II) complex [Cu(pic)2]·2H2O was synthesized with 2-picolinic acid (Hpic) and copper acetate as reactants by room temperature solid-solid reaction. The composition and structure of the complex was characterized by elemental analyses, single crystal X-ray diffraction, X-ray powder diffraction, FT-IR spectroscopy and thermogravimetry-differential scanning calorimetry. The crystal structure of the copper(II) complex belongs to triclinic system and space group , with cell parameters of a = 5.1274(16) A, b = 7.641(2) A, c = 9.209(2) A,α = 74.91(2)°, β = 84.56(2)°, γ = 71.58(3)°, V = 338.48(15) A3, Z = 1, F(000) = 175, R1 = 0.0530, and wR2 = 0.1141. The Cu(II) ion is six-coordinated through two nitrogen atoms from two pyridine rings and four carboxyl oxygen atoms from four different 2-picolinic acid anions, forming an elongated octahedral geometry. The interaction of carboxylate O and Cu(II) forms an one-dimensional chain structure, and the complex exhibits a two-dimensional layered structure by hydrogen bonds. The thermal decomposition processes of the complex under air include dehydration and pyrolysis of the ligand, and the final residue at about 400 °C is copper oxide.

Copper nanoparticles synthesized by thermal decomposition in liquid phase: the influence of capping ligands on the synthesis and bactericidal activity

We explored here the synthesis of copper nanoparticles (CuNPs) by thermal decomposition of copper(II) acetate in diphenyl ether in the presence of different capping ligands. To look for any specific role in thermal decomposition, we performed reactions in the presence of oleic acid, oleylamine, and 1,2-octanediol, or in the presence of different combinations of these capping ligands, or in the absence of them. The CuNPs obtained in the presence of oleic acid and oleylamine (in the presence or absence of 1,2-octanediol) were stabilized as Cu(0) NPs, and the “naked” NPs prepared in solvent only easily oxidized to CuO. Therefore, both oleic acid and oleylamine can act as capping ligands to prepare air-stable Cu(0) NPs. The 1,2-alkyldiol is not necessary for metal reduction during the synthesis, but its presence improves size and morphology control. The presence of capping ligands significantly reduced the bactericidal activity exhibited by the Cu NPs against the gram-negative bacteria Escherichia coli.

DSC kinetics of the thermal decomposition of copper(II) oxalate by isoconversional and maximum rate (peak) methods

The copper(II) oxalate was synthesized, characterized using FT-IR and scanning electron microscopy and its non-isothermal decomposition was studied by differential scanning calorimetric at different heating rates. The kinetics of the thermal decomposition was investigated using different isoconversional and maximum rate (peak) methods viz. Kissinger–Akahira–Sunose (KAS), Tang, Starink1.95, Starink1.92, Flynn–Wall–Ozawa (FWO) and Bosewell. The activation energy values obtained from isoconversional methods of FWO and Bosewell are 0.9 and 3.0 %, respectively, higher than that obtained from other methods. The variation of activation energy, Eα with conversion function, α, established using these different methods were found to be similar. Compared to the FWO method, the KAS method offers a significant improvement in the accuracy of the Ea values. All but the Bosewell maximum rate (peak) methods yielded consistent values of Eα (~137 kJ mol−1); however, the complexity of the thermal decomposition reaction can be identified only through isoconversional methods.

A flexible chemical vapor deposition method to synthesize copper@carbon core–shell structured nanowires and the study of their structural electrical properties

Copper@carbon nanowires (NWs) or nanorods (NRs) with outer diameters between 30 and 90 nm and lengths ranging from 700 nm up to 10 μm have been prepared with high yield via a chemical vapor deposition (CVD) method followed by thermal decomposition of copper(II)-acetylacetonate. The morphology and microstructure of the Cu@C NWs/NRs were characterized by scanning electron microscopy (SEM) and tunneling electron microscopy (TEM), which suggest that these as-grown copper cores with graphite carbon encapsulated inside showed one tip closed and another tip open-ended. The X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX) analysis data indicate that the Cu@C NWs/NRs are free of any contamination, while the electron diffraction (ED) analysis revealed the NWs/NRs to be single crystals. Raman spectra of the deposits obtained with increasing reaction temperature show the transformation tendency from graphite carbon to amorphous carbon. The nanowire/rod growth mechanism has also been discussed. Moreover, Cu@C NWs/NRs are transformed into empty carbon nanotubes with Cu nanoparticles attached to the end after a thermal treatment above 800 °C. This conversion process is of great importance for reuse and recycling of nanomaterials. In addition, electronic transport properties of single nanowire have also been discussed.

Formation Mechanisms of Cu(In0.7Ga0.3)Se2 Nanocrystallites Synthesized Using Hot‐Injection and Heating‐Up Processes

Nearly monodispersed CuIn0.7Ga0.3Se2 (CIGS) nanocrystals were successfully prepared using the thermal decomposition of copper, indium (In), gallium (Ga), and selenium–oleylamine (OLA) complexes via the heating‐up process. The phase formation sequence was CuSe→CuInSe2→CIGS. The CIGS nanocrystals synthesized using the heating‐up process exhibited a single chalcopyrite phase and its chemical composition was close to stoichiometric. However, phase separation of the In‐rich and Ga‐rich phases was found using the hot‐injection method due to the difference in reactivity between In–OLA and Ga–OLA complexes.

Study on thermal decomposition of copper(II) acetate monohydrate in air

The thermal decomposition of copper(II) acetate monohydrate (CuAc2·H2O) under 500 °C in air was studied by TG/DTG, DTA, in situ FTIR and XRD experiments. The experimental results showed that the thermal decomposition of CuAc2·H2O under 500 °C in air included three main steps. CuAc2·H2O was dehydrated under 168 °C; CuAc2 decomposed to initial solid products and volatile products at 168–302 °C; the initial solid products Cu and Cu2O were oxidized to CuO in air at 302–500 °C. The copper acetate peroxides were found to form between 100 and 150 °C, and the dehydration of these peroxides resulted in the presence of CuAc2·H2O above 168 °C. The initial solid products were found to be the admixture of Cu, Cu2O, and CuO, not simply the single Cu2O as reported before. Detailed reactions involved in these three steps were proposed to describe the complete mechanism and course of the thermal decomposition of CuAc2·H2O in air.

Kinetic analysis of the thermal decomposition of copper (I) complexes with heterocyclic thiones

Two series of copper (I) halide complexes formulated as [(L)CuX(μ2-L)2CuX(L)] and [(L)2Cu(μ2-L)2Cu(L)2]2+ 2Χ−, respectively (X = Cl, Br and L = 4,6-dimethylpyrimidine-2-thione (dmpymtH)) were prepared. From the thermogravimetric curves it was found that among the four studied materials, [Cu2(dmpymtH)6]2+2Cl− presents a lower thermal stability. For the determination of the activation energy (E) two different methods have been used comparatively, since every method has its own error. These methods were the isoconversional methods of Ozawa, Flynn and Wall (OFW), and Friedman. The dependence of the E on the value of the mass conversion α, as calculated with OFW and Friedman’s methods, can be separated in three distinct regions. The decomposition mechanism is very complex and can be described using at least three different mechanisms with different activation energies. The best fitting of experimental data with theoretical models gave nth-order for all the three mechanisms (Fn–Fn–Fn).

Synthesis of Stable, Low-Dispersity Copper Nanoparticles and Nanorods and Their Antifungal and Catalytic Properties

Low-polydispersity copper nanoparticles (NPs) and nanorods (NRs) were synthesized by thermal decomposition of copper(II) acetylacetonate precursors in the presence of surfactants. Exchange of weakly bound alkylamine ligands for alkanethiols increased the stability of the NPs and, depending on the thiols’ terminal functionality, rendered them soluble in organic solvents or in water. The water-soluble nanoparticles stabilized with positively charged thiols exhibited long-term (months) stability and antifungal properties. The NPs and NRs stabilized with weakly bound alkylamine ligands are catalytically active in alkyne coupling reactions.

Facile one-step-synthesis of carbon wrapped copper nanowires by thermal decomposition of Copper(II)–acetylacetonate

Carbon wrapped copper nanowires with outer diameters between 100 and 200 nm and lengths ranging from 500 nm up to 10 μm were synthesized by thermal decomposition of Copper(II)–acetylacetonate in a closed, evacuated quartz ampule. The as-grown material consists of a single crystalline copper core wrapped by amorphous carbon. After a thermal treatment near the melting point of copper the carbon wrapped Cu-cable is transformed into an empty carbon nanotube with a spherical Cu particle attached to the end. Due to nanoscale dimension of this material wires a decrease of the melting point of Cu is observed within the carbon shell. We show that the Cu melts already at a temperature of 800 °C. To the best of our knowledge we report for the first time on the emptying of a metal filled carbon nanotube by a thermal treatment. This process is of great importance, e. g. for the application of such nanostructures as nanopipettes or nanocables. Besides, a reversible “filling-emptying process” can be very useful for certain applications.

Thermal decomposition of copper(II) and zinc carbonate hydroxides by means of TG-MS

Thermal decomposition of copper(II) and zinc carbonate hydroxides by means of TG-MS