Monovalent Copper Research Articles

A facile synthesis of Cu(II) diethyldithiocarbamate from monovalent copper-cysteamine and disulfiram

An efficient, atom-economic synthesis of Cu(II) diethyldithiocarbamate from a monovalent copper-cysteamine and disulfiram was developed. • An efficient and atom-economic synthesis of Cu(DDC)2 from DSF and monovalent copper cysteamine (CuCy) is reported. • The chemical structure, proposed reaction mechanism and the optimal reaction conditions were investigated. • The photochemical reactions of Cu(DDC) 2 in five solvents and the possible reaction mechanism were discussed. The copper(II) diethyldithiocarbamate (Cu(DDC) 2 ) complex prepared from disulfiram and Cu(II) species has shown excellent anticancer activity. However, general synthetic methods largely rely on tedious procedures and limited reaction types with undesirable by-products. In this paper, we reported an efficient and atom-economic synthesis of Cu(DDC) 2 from disulfiram and monovalent copper cysteamine (Cu(I)Cy) via a one-step oxidation–reduction reaction. Cu(DDC) 2 was fully characterized by nuclear magnetic resonance (NMR), mass spectrometry (MS), infrared spectroscopy (IR), scanning electron microscope (SEM), X-ray diffraction (XRD), ultraviolet and visible (UV–Vis) spectrophotometry, X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR) and single crystal X-ray diffraction. The proposed reaction mechanism and the effect of reaction conditions on the Cu(DDC) 2 synthesis were investigated. The photochemical reactions of Cu(DDC) 2 was studied in acetone, DMF, toluene, CCl 4 , CHCl 3 under 254, 365 nm alone or combined 254 & 365 nm irradiation based on UV–vis and EPR measurements. The photolysis rate followed in this order: CCl 4 > CHCl 3 > DMF > toluene > acetone. The final photolysis products in CHCl 3 were DSF and Cu 2 (DDC) 2 Cl 2 .

Hypoxic X-irradiation as a trigger for reduction of metal ion and azide-alkyne cycloaddition on oligodeoxynucleotides

A number of bioorthogonal reactions have been designed for the preparation of functional biomolecules to study their biological processes. Among them, the reaction induced by X-irradiation has attracted specific attention because it offers high biopermeability and ease of control of the reaction spatiotemporally. Herein, we demonstrate a Copper-catalysed azide-alkyne cycloaddition initiated by hypoxic X-irradiation. In the system, monovalent copper ions (Cu(I)) were generated by the radiolytic reduction of Cu(II), and the resulting metal ion accelerated the coupling between azide and acetylene molecules. We also found that the present reaction could be applied to the modification of oligodeoxynucleotides bearing acetylene unit even in shielded reaction environments by pork meat.

Octahedron of Zero-Valent and Mono-Valent Copper Anchored on Nitrogen Doping Porous Carbon to Enhance Heterogeneous Electro-Fenton Like Activity

Octahedron of Zero-Valent and Mono-Valent Copper Anchored on Nitrogen Doping Porous Carbon to Enhance Heterogeneous Electro-Fenton Like Activity

Mixed ligand complex of monovalent Copper with benzimidazole derivatives and alanine: synthesis, characterization and antimicrobial studies

Mixed ligand complex of monovalent Copper with benzimidazole derivatives and alanine: synthesis, characterization and antimicrobial studies

Investigation of spectral properties of potassium-aluminum-borate glass with CuCl - CuBr nanocrystals

Heat treatment conditions effect on the characteristics of exciton absorption and luminescence of CuCl and CuBr nanocrystals in potassium-aluminaborate glass is studied. The size effect of the band edge absorption and luminescence energy is confirmed. The simultaneous presence of copper halide nanocrystals and free monovalent copper ions in the glass matrix is shown. Possible conditions for the formation of mixed CuCl-CuBr crystals are considered.

CuO-ZnO-MgO as sustainable and selective catalyst towards synthesis of cyclohexanone by dehydrogenation of cyclohexanol over monovalent copper

• Cyclohexanol was converted into cyclohexanone by dehydrogenation. • Mixed metal oxide CuO-ZnO-MgO (1:1:1) as sustainable and robust catalyst. • The active species was monovalent copper. • No oxidant or coupling reaction was used in parallel. • Hydrogen as co-product can be used for different purposes. Cyclohexanone is the key ingredient for the manufacture of ε-caprolactam which is used for making Nylon 6. In this work, non-oxidative vapor phase dehydrogenation of cyclohexanol to cyclohexanone was carried out over monovalent copper using CuZnMg catalyst. The catalyst was prepared by co-precipitation method and characterized using different techniques, viz. XRD, FTIR, TPD, TPR, TGA, BET, SEM, EDX, and XPS. Cyclohexanol conversion of 55.0 % was resulted with 99.2 % selectivity of cyclohexanone at 260 ℃ with WHSV of 2.34 h −1 . Time on stream study (125 h) and catalyst reusability studies were performed to find that the catalyst was robust, stable and easily reusable. A reaction mechanism over surface Cu + is discussed and kinetics deduced.

Copper loaded HPfCNT/TiO2 ternary nanohybrids as green and robust catalysts for dehydrogenation of cyclohexanol under visible light

Copper doped HPfCNT/TiO2 ternary photocatalysts were fabricated via a low cost, facile, sol-gel cum hydrothermal method at low temperature. Herein, we report energy efficient synthesis of cyclohexanone with high selectivity, through the photocatalytic dehydrogenation of cyclohexanol employing the green and robust ternary nanohybrid photocatalyst. The MWCNTs were functionalized employing the mild and green oxidant H2O2 (HPfCNT). The characterization by XPS spectra showed that Cu existed as +1 oxidation state. The monovalent copper species (as Cu2O) accounted for the greater conversion and better selectivity in the copper doped ternary hybrid system. The synergistic effects of copper and HPfCNTs with TiO2 imparted better visible light harvesting properties for the efficient photocatalytic dehydrogenation. It was evidenced from the activity studies and characterization employing UV–Vis DRS, PL spectra, XPS, BET analysis and elemental mapping.

Acid Bioleaching of Copper from Smelter Dust at Incremental Temperatures

ABSTRACT Copper smelters produce solid waste streams that pose potential pollution problems because of the dust and metal content. Dust from flash and electric furnace smelters is normally recycled to the smelting process, but this decreases the capacity for concentrate feed, and increases impurities and carryovers in the dust with time. The purpose of this study was to test an acid bioleaching process for recovering copper from a sample of smelter dust. The dust sample contained delafossite, chalcocyanite, and chalcopyrite as the main Cu-minerals. Smelter dust (10% pulp) in acid leach solution was subjected to three microbial cultures in a sequence of 35°C, 50°C, and 70°C incremental temperatures for 2 days each. Up to 83% copper dissolution from the dust was achieved by the combined action of the three-phase bioleaching and chemical leaching over the contact time of 6 days. Chemical acid demand at 70°C solubilized 68% Cu from smelter dust within 2 h, attributed to chalcocyanite dissolution in the dust. The monovalent copper minerals chalcopyrite and delafossite were more recalcitrant than the sulfate phase chalcocyanite. A 16-day bioleaching experiment at 35°C and 50°C yielded copper recoveries, which were comparable to those obtained in the three-phase bioleaching. It was concluded that further increases in copper yields from smelter dust require extended contact time ideally at the extreme thermophilic temperature range and stirred bioreactor conditions to control key parameters.

Optical properties of multinary copper chalcogenide semiconductor nanocrystals and their applications in electroluminescent devices

In the past few decades, semiconductor nanocrystals (semiconductor quantum dots) have received widespread attention due to their high color purity and size-dependent optical properties as well as their potential applications in the next generation of lightening and displays. At present, most of the emitting layer materials in the quantum-dot electroluminescent devices are focused on cadmium-based chalcogenide quantum dots, but cadmium is harmful to the environment and human health, which faces great challenges in the future commercialization. Therefore, it is necessary to develop an environment-friendly, cadmium-free semiconductor quantum dot with excellent optoelectronic performance. In recent years, multinary copper chalcogenide semiconductor nanocrystals have attracted extensive attention due to their low toxicity, tunable luminescent properties and potential applications in optoelectronic devices. Ternary copper-based chalcogenide semiconductor nanocrystals (such as CuInS2, etc.) can be considered as the counterparts of the II-VI compounds, in which the divalent metal ions (such as Zn2+, etc.) are replaced by monovalent copper ions (Cu+) and trivalent indium ions (In3+). As a result, the crystal structure of ternary I-III-VI nanocrystals is similar to that of II-VI nanocrystals. Up to date, ternary CuInS2 nanocrystals are the most widely studied among different multinary copper chalcogenide semiconductor nanocrystals. The crystal structure of ternary CuInS2 nanocrystals mainly includes sphalerite, wurtzite and chalcopyrite phase, and different-phase CuInS2 nanocrystals often have different optical band gaps. With the development of colloidal chemical synthetic technique, most of the multinary copper chalcogenide semiconductor nanocrystals can be synthesized through a colloidal chemical method. The reaction parameters including temperature, reaction precursor activity and surface ligand in the synthesis process play an important role in the tuning of the size, morphology and composition of the resultant nanocrystals. Generally, ternary CuInS2 nanocrystals have a low photoluminescence quantum yield due to their internal and surface defects. Since most of the multinary copper chalcogenide semiconductor nanocrystals exhibit non-stoichiometric characteristics, the number of copper vacancies also affects their luminescence performance to some extent. In order to improve the luminescence performance, it is a common strategy to introduce Zn2+ into the Cu-In-S system to form a quaternary Cu-In-Zn-S alloyed structure or grow a wide-band gap semiconductor material (such as ZnS) onto its surface to form a core-shell structure. However, due to higher ion mobility of copper ions at a relatively high temperature and the similar radius of Cu+ ion and Zn2+, cation exchange reaction is likely to occur in the epitaxial growth of ZnS shells. Therefore, it is difficult to distinguish the alloyed and core-shell structure for the multinary copper chalcogenide semiconductor nanocrystals. With the in-depth understanding of the relationship between the nanostructure and luminescence properties of multinary copper chalcogenide semiconductor nanocrystals, these nanocrystals have been widely used as light-emitting layers in electroluminescent devices, and a significant progress has been made. At present, different strategies have been exploited to improve the device performance of the electroluminescent devices based on multinary copper chalcogenide semiconductor nanocrystals, such as changing the device structure, regulating the nanostructure of materials, and device interfacial engineering. This review gives a detailed summary on the relationship between the composition, surface ligands, crystal structure as well as the nanostructures and optical properties of the multinary copper chalcogenide semiconductor nanocrystals. Moreover, the progress of electroluminescence devices based on the multinary copper chalcogenide semiconductor nanocrystals is highlighted, and finally the prospect of the development of multinary copper chalcogenide semiconductor nanocrystals is concluded.

Hydrometallurgical recovery of high-purity copper cathode from highly impure crude copper

A new hydrometallurgical route was investigated in which a pure copper cathode was recovered from crude copper containing high amounts of impurity elements. As an example of crude copper, copper powder obtained from a top submerged lance furnace, which was pulverized by atomization from molten copper, was used. The selective leaching of copper was achieved using an ammoniacal alkaline solution containing divalent copper ammine complexes and ammonium chloride with most impurities (e.g. silver and gold) remaining in the residue. However, some impurities, such as nickel, arsenic, antimony, and lead were dissolved. Purification steps using hydroxyapatite and magnesium chloride were effective at removing lead, antimony, and arsenic. On the basis of these results, copper cathode recovery from crude copper was examined. As a result, a sufficiently pure copper cathode was finally obtained by monovalent copper electrolysis, which indicated the possibility of using this process as a new route for recovering pure copper from highly impure crude copper.

Radiation–Chemical Reduction of Cu2+ Ions in an Aqueous Solution

Upon irradiation with accelerated electrons of aqueous solutions of copper salts containing methyl alcohol, the formation of a precipitate containing metallic copper and monovalent copper oxide Cu2O is observed in a mass ratio of 75.2 and 24.8%, respectively. The process of metal precipitation and its properties were studied. The radiation–chemical yield of the mass of the precipitated precipitate is (7.2 ± 0.2) × 10–3 g/kGy. The efficiency of the radiation method for the reduction of copper from aqueous solutions of its salts has been substantiated. The method can be promising for the production of precipitates of pure and amorphous metals, as well as for the treatment of water effluents containing toxic transition metals.

Octahedron of Zero-Valent and Mono-Valent Copper Anchored on Nitrogen Doping Porous Carbon to Enhance Heterogeneous Electro-Fenton Like Activity

Octahedron of Zero-Valent and Mono-Valent Copper Anchored on Nitrogen Doping Porous Carbon to Enhance Heterogeneous Electro-Fenton Like Activity

Copper-doped quasi-one-dimensional ZnO for effective photooxidation of As (III) to As (V) in visible light

By temolysis of the Zn1− Cu (HCOO)(OCH2CH2O)1/2 complexes in one step Zn1− Cu O solid solutions were obtained. Сopper in these materials is a regulator of the photoactivity and morphology of aggregates. According to TEM, XPS, optical spectroscopy, and voltammetry, all samples studied contain monovalent copper. It was shown that the maximum photoactivity in the reactions of photooxidation of As in UV and blue light has Zn1− Cu O (0<x<0.1) solid solutions with tubular particle morphology. With an increase in concentration up to 10 at.%, сopper manifests itself as an electron acceptor, which reduces the efficiency of the catalyst in both light ranges.
 Keywords: photocatalyst, Cu-doped ZnO, heterostructures, wide-band-gap semiconductors, precursor synthesis

STRUCTURE OF “COORDINATION OLIGOMERS” BASED ON COMPLEXES OF THIOPHOSPHORYLTHIOUREA COMPOUNDS WITH MONOVALENT COPPER AND SILVER CATIONS

Molecular and crystal structures of two polynuclear complexes of monovalent silver and copper with chelate thiophosphorylthiocarbamide ligands is determined within the study of complexing properties of N-thiophosphorylated thioureas with respect to copper(I) and silver(I) cations. In crystals, these complexes are shown to form “coordination oligomers” (closed polynuclear complexes) through coordination bonds of bridging sulfur atoms of thiocarbamide groups.

Reactions of a pincer proligand with copper iodide: bridging instead of C–H metalation

Various precursors of divalent copper have been treated with the meta-disubstituted phenylene-based proligand POC(H)OP (1,3-(i-Pr2PO)2C6H4) with the objective of preparing classical pincer complexes (POCOP)CuX. However, in no case was such species obtained, presumably owing to the difficult C–H metallation step. Analogous reactions of monovalent precursors were also unsuccessful, whereas reaction of POC(H)OP with CuI under different conditions gave the non-metallated adducts {(μ, κP, [Formula: see text]-POC(H)OP)Cu(μ-Ι)}2, 1, {(μ, κP, [Formula: see text]-POC(H)OP)Cu2(μ-Ι)2(DMAP)2}, 2 (DMAP = 4-dimethylaminopyridine), and {(μ, κP, [Formula: see text]-POC(H)OP)Cu2(μ3-Ι)2}2, 3. Treating 1 with DMAP gave the adduct 2, whereas 3 could be obtained by treating 1 with BuLi or by sublimation of 1. The solid state structures of these complexes revealed the tetrahedral geometry that might be anticipated for the d10 Cu(I) centers, in addition to fairly close I–H distances; on the other hand, no C–H interaction (agostic or otherwise) was observed with the Cu centers in any of these structures. The unsuccessful metallation of the C(2)–H moiety is thought to be a result of the strong preference of monovalent copper center to form bridging interactions with iodide and the POC(H)OP ligand; this appears to prevent the approach of the central carbon of the ligand to the Cu centers.

Evaluation of Sustained Antibacterial Effect of Alcohol-Based Disinfectant Containing Monovalent Copper Compound Against Antibiotic-Resistant Bacteria

Background Monovalent copper compounds have high antiviral and antibacterial activity. Unlike divalent copper compounds, monovalent copper compounds can generate hydroxyl radical which causes oxidative damage to microorganisms. However, the antibacterial activity of monovalent copper compounds against antibiotic-resistant bacteria is not clear. The objective of this study is to evaluate the sustained antibacterial activity of alcohol disinfectant containing monovalent copper compound against antibiotic-resistant bacteria and to compare its antibacterial activity with those of conventional disinfectants. Methods Monovalent copper compound dispersed in 70% ethanol (Ethanol/monovalent copper) was applied on stainless plate by swabbing with cotton fabric. Ethanol (70%), sodium hypochlorite (5000 ppm), and benzalkonium chloride (0.2%) were also applied for comparison. After each disinfectant was dried, each bacterial suspension of antibiotic-resistant bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistant Acinetobacter baumannii (MDRA), was dropped onto the stainless plate sample. Viable bacteria were evaluated at 1 and 3 hours after each bacterial suspension was applied. Results As compared to the untreated stainless plate, the stainless plates treated with Ethanol/monovalent copper, ethanol, sodium hypochlorite, and benzarconium chloride showed log reductions in the average number of CFUs, 1.08, -0.10, -0.56, and 0.83 log10 at 1 hour contact, >4.01, 0.08, -0.86, and 1.63 log10 at 3 hour contact for MRSA, and >4.86, -0.16, -0.08, and 3.61 log10 at 1 hour contact, >5.14, -0.04, -0.07, and 4.28 log10 at 3 hour contact for MDRA, respectively. Conclusions This study demonstrated that ethanol/monovalent copper have sustained antibacterial activity against MRSA and MDRA even after drying. The antibacterial activity is also higher than a quaternary ammonium salt, benzalkonium chloride which is widely used in healthcare settings. These study findings suggest that monovalent copper compounds serve as a continuously active disinfectant against antibiotic-resistant bacteria in the healthcare environment. Monovalent copper compounds have high antiviral and antibacterial activity. Unlike divalent copper compounds, monovalent copper compounds can generate hydroxyl radical which causes oxidative damage to microorganisms. However, the antibacterial activity of monovalent copper compounds against antibiotic-resistant bacteria is not clear. The objective of this study is to evaluate the sustained antibacterial activity of alcohol disinfectant containing monovalent copper compound against antibiotic-resistant bacteria and to compare its antibacterial activity with those of conventional disinfectants. Monovalent copper compound dispersed in 70% ethanol (Ethanol/monovalent copper) was applied on stainless plate by swabbing with cotton fabric. Ethanol (70%), sodium hypochlorite (5000 ppm), and benzalkonium chloride (0.2%) were also applied for comparison. After each disinfectant was dried, each bacterial suspension of antibiotic-resistant bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistant Acinetobacter baumannii (MDRA), was dropped onto the stainless plate sample. Viable bacteria were evaluated at 1 and 3 hours after each bacterial suspension was applied. As compared to the untreated stainless plate, the stainless plates treated with Ethanol/monovalent copper, ethanol, sodium hypochlorite, and benzarconium chloride showed log reductions in the average number of CFUs, 1.08, -0.10, -0.56, and 0.83 log10 at 1 hour contact, >4.01, 0.08, -0.86, and 1.63 log10 at 3 hour contact for MRSA, and >4.86, -0.16, -0.08, and 3.61 log10 at 1 hour contact, >5.14, -0.04, -0.07, and 4.28 log10 at 3 hour contact for MDRA, respectively. This study demonstrated that ethanol/monovalent copper have sustained antibacterial activity against MRSA and MDRA even after drying. The antibacterial activity is also higher than a quaternary ammonium salt, benzalkonium chloride which is widely used in healthcare settings. These study findings suggest that monovalent copper compounds serve as a continuously active disinfectant against antibiotic-resistant bacteria in the healthcare environment.

Synthesis of crotonic acid from ethanol by sequential catalysis

Catalytic processes are important components of sustainable chemistry. We present a novel process to synthesize crotonic acid by sequential catalytic oxidation-condensation-oxidation reactions in a Soxhlet extractor. Oxidation of ethanol and crotonaldehyde is catalyzed by a new composite Cu/H3PO4 catalyst characterized by XRD (X-ray Diffraction), BET (Brunauer-Emmett-Teller analysis), TEM (Transmission Electron Microscopy), XPS (X-ray Photoelectron Spectrometry), and TG (Thermogravimetric analysis), showing higher activity and better stability compared to nano-copper, due to dispersion by a mutual support; external temperature compensation during the reaction allows ethanol oxidation without degradation of the catalyst. XRD and XPS analyses of the used catalyst reveal that monovalent copper is the active species for ethanol oxidation. The catalyst is effectively recovered and reused four times. Nano MgO catalyzes acetaldehyde condensation under mild conditions and can be recycled during the process. Conversion of ethanol is greater than 48%, and the selectivity to crotonic acid is 84% in the continuous process.

Зависимость физико-механических свойств медных покрытий от состава раствора химического меднения

Chemical production of metal coatings is relevant and widely sought after. The field of practical use of chemical metal deposition reactions from aqueous solutions are continuously expanding. These reactions are widely used to obtain metal coatings for various purposes and begin to be used for the selective deposition of metals on a substrate in the form of patterns. Chemical copper plating has gained great practical importance. In additive and subtractive technology for the production of printed circuit boards, thick-layer chemical copper plating solutions are used to obtain a circuit diagram and metallization of holes. These are solutions that avoid the stage of galvanic copper plating, since the chemically deposited copper layer is sufficiently thick and allows further technological operations to be carried out. Chemical copper plating solutions must be stable, work with a sufficient copper plating rate and, most importantly, the resulting copper coatings have high physical and mechanical properties. This is due to the fact that during operation, printed circuit boards can be significantly heated, which leads to thermal expansion of both the board material and the copper coating. Due to the difference in the linear expansion coefficients of the substrate material and the deposited copper, significant stresses can occur in the copper layer deposited on the walls of the holes of the printed circuit board. When applying an inelastic copper coating, the layer breaks and the board exits the operating mode. This work is devoted to the study of the effect of some inorganic oxidizing agents on the properties of chemically precipitated copper, and this effect mainly affects the reduction of oxygen fragility. The mechanism of the process of chemical copper plating of a dielectric surface activated by palladium(II) salts is considered in detail. It is shown that at a high deposition rate of chemical copper, hydrogen is included in the coating, which leads to the appearance of “hydrogen” brittleness. Bubbling a solution of chemical copper plating with air increases the stability of the solution and can be used to oxidize certain forms of organic additives introduced into the solution to reduce hydrogen embrittlement. It is established that the incorporation of particles of copper oxide or hydroxide of monovalent copper into the copper coating leads to a decrease in the ductility of the copper coating and a decrease in the relative elongation of the chemically deposited copper layers. It was shown that in order to reduce the “oxygen” brittleness or increase the ductility of copper coatings, inorganic oxidants  ammonium persulfate and ferric sulfate salts must be introduced into the solution of chemical copper plating. Based on the experiments, it was found that in order to improve the ductility of the resulting copper coatings, ferric sulfate (Fe2(SO4)3∙9H2O) in the amount of 0.15-0.2 gl1. The conducted research cycle allowed us to recommend the following composition of a solution of thick-layer chemical copper plating, mol∙l–1: CuSO4 – 0.1; KNaTart – 0.21; NaOH – 0.375; Na2CO3 – 0.028; K3Fe(CN)6 – 3∙10–5; Fe2(SO4)3 – 3∙10–4; NiCl2 – 1.3∙10–2; ПАВ-2К – 0.1 g/l; formaldehyde – 25 mll1 40% solution. The solution is stable during operation, the coating deposition rate is from 3 to 4 μmh1, the plasticity of the resulting copper layers is 4-5%.

A Rechargeable Zinc-Copper Battery Based on the Combination of a Monovalent Cationic Exchange Membrane and an Inert Charge Shuttle

To reach their full potential, renewable and intermittent energy sources such as wind and sun need to be coupled with a cost effective energy management system that is able to convert, store, and delivery energy as required. The Daniell element is one of the earliest non-rechargeable batteries. It is based on abundant, cost-effective and environmentally-benign materials and the chemistry relies on reduction of copper at the positive electrode and oxidation of zinc at the negative electrode. Since both electrodes are immersed in different electrolytes, they have to be separated by a porous barrier or a salt-bridge in order to prevent the self-discharge of the battery. However, these separators are not selective and copper ions migrate over time to the negative electrode and deposit on the surface of the zinc electrode which reduces shelf time and makes recharging of the element impossible.In this work, we report on a novel Zinc-Copper battery design which is based on the application of a selective cation exchange membrane in conjunction with an unreactive sodium background electrolyte which acts as a charge shuttle. The membrane is impermeable for the copper (and zinc) ions but allows the sodium ions to migrate between the two half-cells to maintain the electro-neutrality.We first tested the suitability of different zinc-based electrolytes, including zinc sulfate, zinc chloride, and zinc nitrate. At equal electrolyte conductivities, we found a higher potential for the zinc deposition in sulfate electrolytes compared to that in chloride electrolytes. It was also observed that the zinc electrode passivated due to the formation of zinc oxide (ZnO) when operated in a zinc nitrate solution. In terms of the electrodeposition of copper, sulfate and nitrate-based electrolytes showed a nearly equal potential. However, chloride-based copper electrolytes shifted the potential to more negative values due to the stabilization of the monovalent copper ion intermediate.The membrane selectivity was evaluated by monitoring the crossover of copper ions into the zinc half-cell for various concentrations of copper in the copper half-cell. After seven days of open circuit operation, we measured copper concentrations below 10 ppm in the zinc half-cell when there was 0.1 M of copper sulfate in the copper half-cell. When the copper half-cell was filled with 0.5 M copper sulfate, the effect of crossover was evident by a blue tint of the electrolyte and the Zn electrode was covered with a layer of black/red deposit.Hence, we chose a conservative catholyte composition of 0.1 M copper sulfate and 1M sodium sulfate in the battery. We performed discharge measurements where we varied the discharge current density and measured the voltage over time. Discharge continued until a cell voltage of 0 V was reached, which corresponds to a complete consumption of the copper ions in the catholyte. Indeed, it turned out that we utilized only around 3 to 6 % of the zinc electrode and less than 1 % of the copper electrode during discharge. These very low values indicate that the present system could also be favorably-designed as a hybrid redox (flow) battery. Hence, for the current preliminary cell design it is seems reasonable to normalize the current with the mass of the initial copper ion content since it is the limiting electro-active species. At 0.5 mA/cm2 (421 mA/g), the battery was discharged for around 17 hours before all of the copper ions were consumed resulting in a specific capacity of 763 mAh/g. The theoretical charge content based on the initial copper concentration was 843 mAh/g giving a faradaic yield of 90.5 %. The capacity and faradaic yield of the discharge at 1 mA/cm−2 (842 mA/g) were 583 mAh/g and 69.2 %, respectively.The recharge-ability of the battery was investigated over 100 charge-discharge cycles at a current density of ±0.5 mA/cm2. The average capacity was 530 mAh/g while the average exergy efficiency was 74 %. The deviations over the cycle numbers are less than 5 % of the average values. In other words, there was no clear increase or decrease during operation, indicating a steady performance. Afterwards, the zinc electrode was characterized using Energy-dispersive X-ray spectroscopy. Only a very small amount of deposited copper was found, indicating a negligible copper ion cross over. This verifies that the combination of a cost-effective monovalent cation exchange membrane along with an unreactive background electrolyte imparts recharge-ability to the Daniell cell. Figure 1

Synthesis of Two-dimensional Hydrophobic Copper-based Nanosheets and Their Application in Catalytic Oxidation of Sulfides

Two-dimensional nanomaterials have received extensive attention because of their unique physicochemical properties. However, bottom-up synthesis of two-dimensional (2D) stable nanomaterials still remains great challenge. In this work, a novel 2D metal-organic (Cu-BDT) nanosheet is constructed at room temperature by coordinative self-assembly, namely, using monovalent copper ion as the metal precursor and 1,4-benzenedithiol as organic ligand. As-synthesized Cu-BDT nanosheets are fully characterized by various techniques including powder-diffraction of X-rays (P-XRD), Fourier transform infrared spectrometer (FT-IR), Raman spectra (Raman), scanning electron microscopy (SEM), transmission electron microscope (TEM), atomic force microscope (AFM), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma optical emission spectrometer (ICP-OES) and contact angle test. The catalytic result verifies that the Cu-BDT nanosheet surfaces possess abundant active sites and good hydrophobicity, which facilitate oxidation of sulfides into sulfoxide compounds.