Nickel Salts Research Articles

One‐step hydrothermal synthesis of the FeNi3/rGO composite for electrochemical supercapacitor

Intermetallic compounds are commonly used in semiconductor, shape memory materials, hydrogen storage materials and magnetic materials due to their unique physical and chemical properties. In this study, the FeNi3/rGO (rGO: reduced graphene oxide) composite was prepared by one-step hydrothermal method using water-soluble nickel and iron salts as metal sources and hydrazine hydrate as reducing agent in alkaline solution. The structure of the composites are characterized by XRD, FTIR, XPS and Raman spectroscopy. The micromorphology of the samples is observed by SEM and TEM. The electrochemical performance of the FeNi3/rGO composite is evaluated by electrochemical impedance spectroscopy (EIS), galvanostatic charge–discharge (GCD) and cyclic voltammetry (CV). The results indicate that when the scan rate is 10 mV s−1 in 4 M KOH electrolyte solution, the specific capacitance of the FeNi3/rGO composite is 169.42 F g−1. At a current density of 1 A g−1, the specific capacitance of the FeNi3/rGO composite remains 82.72% of the original energy after 3000 cycles. Therefore, the FeNi3/rGO composite has excellent capacitance performance and is expected to be applied in supercapacitors and nanodevices in the future.

Al(NO3)3 Induced Morphological Changes in Nickel and Cobalt Salts as Advanced Electrodes for Supercapacitors

Abstract As one of the important components of the supercapacitor, electrode material has a significant influence on the electrochemical performance of the device. In this study, Ni2(NO3)2(OH)2 · 2H2O/(Co(NH3)5(N3))(N3)2 (NC) composite material was prepared by the microwave-assisted method. The effects of Al(NO3)3 contents on the morphology and structure of the composites were studied by scanning electron microscopy, X-ray diffraction, Raman spectrum, and laser particle size distribution analyzer. The capacitive properties of the composite were analyzed by cyclic voltammetry, constant current charge and discharge, and electrochemical impedance spectroscopy measurements. The results show that the Al(NO3)3 has a significant effect on the morphology and capacitance of NC. When the contents of Al(NO3)3 are 0, 5, 10, 15, and 20 wt%, the discharge capacities of NC, NCA-5, NCA-10, NCA-15, and NCA-20 samples obtained under 1 A/g current density are 1674, 1759, 2645, 1098, and 1321 F/g, respectively. At higher current densities of 4, 7, and 10 A/g, the discharge specific capacities reached 1350, 1064, and 894 F/g, indicating that the NCA-10 composite is a promising electrode material for supercapacitors.

Anion Controlled Stereodivergent Semi‐Hydrogenation of Alkynes using Water as Hydrogen Source

AbstractAn anion controlled stereodivergent semi‐hydrogenation of alkynes is reported. The reactions are catalyzed by the low‐cost and stable nickel(II) salts, using water as environmental friendly hydrogen source with zinc powder as metal reductant. Interestingly, the stereoselectivity of the reaction is well controlled by the anion of the nickel(II) salt. The present methodology allowed a low‐cost and convenient preparation of trans‐ and cis‐alkenes under mild conditions. The reaction mechanism is proposed with water as the hydrogen donor on the basis of the control experiments.

Molecular S = 2 High-Spin, S = 0 Low-Spin and S = 0 ⇄ 2 Spin-Transition/-Crossover Nickel(II)-Bis(nitroxide) Coordination Compounds

Heterospin systems have a great advantage in frontier orbital engineering since they utilize a wide diversity of paramagnetic chromophores and almost infinite combinations and mutual geometries. Strong exchange couplings are expected in 3d–2p heterospin compounds, where the nitroxide (aminoxyl) oxygen atom has a direct coordination bond with a nickel(II) ion. Complex formation of nickel(II) salts and tert-butyl 2-pyridyl nitroxides afforded a discrete 2p–3d–2p triad. Ferromagnetic coupling is favored when the magnetic orbitals, nickel(II) dσ and radical π*, are arranged in a strictly orthogonal fashion, namely, a planar coordination structure is characterized. In contrast, a severe twist around the coordination bond gives an orbital overlap, resulting in antiferromagnetic coupling. Non-chelatable nitroxide ligands are available for highly twisted and practically diamagnetic complexes. Here, the Ni–O–N–Csp2 torsion (dihedral) angle is supposed to be a useful metric to describe the nickel ion dislocated out of the radical π* nodal plane. Spin-transition complexes exhibited a planar coordination structure in a high-temperature phase and a nonplanar structure in a low-temperature phase. The gradual spin transition is described as a spin equilibrium obeying the van’t Hoff law. Density functional theory calculation indicates that the energy level crossing of the high- and low-spin states. The optimized structures of diamagnetic and high-spin states well agreed with the experimental large and small torsions, respectively. The novel mechanism of the present spin transition lies in the ferro-/antiferromagnetic coupling switch. The entropy-driven mechanism is plausible after combining the results of the related copper(II)-nitroxide compounds. Attention must be paid to the coupling parameter J as a variable of temperature in the magnetic analysis of such spin-transition materials. For future work, the exchange coupling may be tuned by chemical modification and external stimulus, because it has been clarified that the parameter is sensitive to the coordination structure and actually varies from 2J/kB = +400 K to −1400 K.

Oriented Nickel Nanonetworks and Their Submicron Fibres as a Basis for a Transparent Electrically Conductive Coating.

The paper demonstrates a technique for applying an oriented nickel network to a glass surface. The method is based on the chemical reduction of nickel salt. The shaping and orientation of the resulting system are carried out using a micellar template of a surfactant and a magnetic field. Submicron nickel fibres are used to impart unity to the plurality of individual-oriented nickel nanonetworks. The result is a single conductive coating on the surface of the glass, which has a transparency in the optical range. Investigations of the structure, chemical composition, morphology and electrical conductivity of the coating were performed.

Synthesis, characterization and Hirshfeld surface analysis of a mixed-ligand copper (II) coordination polymer from 1,4,8,11-tetraazacyclotetradecane and pyromellitic dianhydride

One pot synthesis of a new mixed-ligand coordination polymer has been carried out by combining copper salt, macrocyclic ligand 1,4,8,11-tetraazacyclotetradecane (cyclam) and benzene-1,2,4,5-tetracarboxylic dianhydride (pyromellitic dianhydride, PMDA). The molecular composition of the synthesized complex was found to be [Cu(H2btca)2(H2O)2Cu(cyclam)]·H2O [H2btca = 1,2,4,5-benzene tetracarboxylic dianion]. The complex has been characterized by physicochemical and spectroscopic methods. Its crystallographic analysis shows two different types of Cu(II) atoms (Cu1 and Cu2) in octahedral environments. In the structure, the coordination of bidentate H2btca2− dianion with Cu1 atoms in 1,4-COO− position forms a two-dimensional (2D) sheet, while the O(µ2)-axial atoms of water ligands coordinated to [Cu(cyclam)]2+ units with long Cu2-Ow bond indicates a Jahn–Teller distortion effect producing a three-dimensional (3D) network. Using the same combination of ligands (cyclam and PMDA) with nickel salt led to an already reported one dimensional (1D) polymer, viz. {[Ni(cyclam)H2btca]·2H2O}n. Hirshfeld surface analysis on H2btca2− dianion along with 2D fingerprint plots was carried out in order to have an in-depth understanding of the intermolecular interactions in the crystal system.

The Effect of Ni Precursor Salts on Diatomite Supported Ni-Mg Catalysts in Methanation of CO<sub>2</sub>

This study is aimed to investigate the effect of Ni precursor salts on the properties (textural, phase-structural, reducibility, and basicity), and catalytic performance of diatomite supported Ni-Mg catalyst in methanation of CO2. The NiMg/D-X catalysts derived from various nickel salts (X = S-sulfamate, N-nitrate or A-acetate) were synthesized by the precipitation-deposition (PD) method. The catalysts were characterized by N2-physisorption, XRD, TPR-H2, and TPD-CO2 techniques. The different catalytic activity (conversion) and selectivity, observed in CO2 methanation carried out under relatively mild conditions (atmospheric pressure; temperatures: 250-450 °C) are related and explained by the difference in textural properties, metallic Ni-crystallite size, reducibility, and basicity of studied catalysts. The results showed that catalyst derived from Ni-nitrate salt (NiMg/D-N) is more suitable for the preparation of efficient catalyst for CO2 methanation than its counterparts derived from sulfamate (NiMg/D-S) or acetate (NiMg/D-A) nickel salt. The NiMg/D-N catalyst showed the highest specific surface area and total basicity, and the best catalytic performance with CO2 conversion of 63.3 % and CH4 selectivity of 80.9 % at 450 °C.

The synthesis of crystalline Ni microwire-nanosheet monolith for recoverable host of dendrite-free Li anode

Lithium metal has the highest theoretical energy density and the lowest redox potential among Li-ion battery anodes, but often suffers from Li dendrite-related safety problem. Here, we describe a hierarchical Ni monolith of interconnected crystalline microwires covered with vertical nanosheets synthesized for a recoverable host of dendrite-free Li. The metallic Ni–Li anode exhibits high capacity, high Coulombic efficiency and high-rate cyclability (over 690 cycles at an ultrahigh current density of 40.0 mA cm−2). The Ni monolith, derived from the chain chelation of acetate anions, nickel cations and hydrazine molecules, features high conductivity, high flexibility, low density, hierarchical pores and lithiophilic surface oxidation. This special structure enables fast electrolyte wetting, Li+ flux homogenization and uniform electric field to seed Li metal, which can work as a recyclable, light and conductive host inhibiting dendritic Li growth at various current densities. Our investigation demonstrates that the cheap acetate nickel salt can be used to fabricate nanostructured Li host for Li-ion battery anode.

Antiproliferative activity and electrochemical oxygen evolution by Ni(II) complexes of N'-(aroyl)-hydrazine carbodithioates.

The electrochemical water splitting by transition metal complexes is emerging very rapidly. The nickel complexes also play a very vital role in various biological activities. Here, three new ligands {H2mbhce = N'-(4-methyl-benzoyl), H2pchce = N'-(pyridine-carbonyl) and H2hbhce = N'-(2-hydroxy-benzoyl) hydrazine carbodithioic acid ethyl ester} and their corresponding Ni(II) complexes [Ni(Hmbhce)2(py)2] (1), [Ni(pchce)(o-phen)2]·CH3OH·H2O (2) and [Ni(hbhce)(o-phen)2]·1.75CHCl3·H2O (3) have been synthesized and fully characterized by various physicochemical and X-ray crystallography techniques. The photoluminescence study and thermal degradations were also examined. The treatment of K562 cells with the increasing concentrations of the nickel salts, ligands, and complexes 1, 2, and 3 showed dose-dependent cytotoxicity. The cytotoxic activity of ligands reveals that ligand H2mbhce is more potent in inhibiting the growth of tumor cells in comparison to other ligands H2pbhce and H2hbhce. Cytotoxicity assay results indicate that all complexes have remarkable cytotoxic potential in comparison to either nickel salts or the free ligands. Among these complexes, complex 1 has significantly better anti-tumor activity as compared to complexes 2 and 3. The electrochemical study of complexes 1, 2, and 3 for water oxidation reveals that all the complexes possess admirable electrocatalytic activity towards oxygen evolution reaction (OER) and have lower overpotential (328, 338, and 370 mV, respectively) than many previously reported complexes and RuO2 (390 mV). Among complexes 1, 2, and 3, complex-2 shows a better water oxidation response. Consequently, these complexes have great potential to be utilized in fuel cells. The more reliable electrochemical parameter TOF is also calculated for all three complexes.

Tungsten-rich Ni-W coatings, electrodeposited from concentrated electrolyte for complex geometry parts protection

AnnotationThe process of electrodeposition of nickel-tungsten coatings from a citrate electrolyte with an increased concentration of salts of the deposited metals has been investigated. Based on the results of studying the effect of pH, the ratio of the concentrations of nickel and tungsten salts in the electrolyte, the temperature of the electrolyte on the composition and current efficiency of the Ni-W alloy, optimal conditions have been determined that make it possible to obtain Ni-50% W coatings at a rate acceptable for industrial use. Evaluation of the properties of the coating showed that it is non-porous and has a microhardness of 600-640 HV.

Influence of Ni (II) oxime complex coupled with the combination of diverse sized ZnO nanoparticles on Photovoltaic Performance

The one side selective synthesis of quinoline carboxylic acid oxime complex was carried out successfully. The as-prepared quinoline carboxylic acid oxime complex was complexed with nickel (II) salts to form nickel (II) oxime complex. These complexes were further adsorbed onto ZnO films containing ZnO nanoparticles of various sizes. ZnO films containing a diverse proportion of ZnO nanoparticles were investigated to enhance the photovoltaic efficiency of the dye-sensitized solar cell. The as-synthesized complex was characterized by scanning electron microscopy (SEM), Ultra violet visible spectroscopy (UV-vis), Fourier Transform Infrared Spectroscopy (FT-IR) spectroscopy, 1Hydrogen Nuclear magnetic resonance spectroscopy (1HNMR), Liquid chromatography coupled with mass spectrometry (LC-MR), Brunauer–Emmett–Teller (BET), and Attenuated total reflection Infra-red spectroscopy (ATR-IR). The combination of large and small ZnO nanoparticles has significantly improves the photovoltaic efficiency. The optimum mixing ratio for the best performance (0.127%) of a dye-sensitized solar cell is achieved by mixing the small: large ZnO particles in a ratio 60:40. The increased efficiency is due to the harvesting of light caused by scattering effect from larger sized ZnO particles. The ZnO layer consisting of smaller particles which are very next to the ZnO bigger particles makes a good electronic contact between film electrode and the Indium-doped tin oxide glass substrate resulting in the increases in the dye molecules adsorption. The over-layered, large-sized ZnO particles enhance the light-harvesting by light scattering effect. Compared to the other mixtures of ZnO films, there is a decrease in the photovoltaic performance of the solar cell when ZnO particles (small and large in a ratio 1:1) were adsorbed onto the Ni (II) oxime complex, which are caused due to the decrease in the surface area and dye aggregation.

Efficient coating of titanium composite electrodes with various metal oxides for electrochemical removal of ammonia

A variety of coated titanium (Ti) electrodes were prepared for ammonia wastewater treatment. The influence of precursor salts in the prepared coatings of the titanium plate electrodes was investigated using thermal decomposition by different dissolved nickel (Ni), copper (Cu), tin (Sn), and antimony (Sb) chloride salts. The metal chlorides (tin chloride SnCl4·5H2O, nickel chloride NiCl2·6H2O, antimony chloride SbCl3, and cupric chloride CuCl2·2H2O) were dissolved in a suitable solvent to prepare three kinds of solutions with the following mole ratios: 98.2:1.6:0.2, Sn:Sb:Cu; 98.2:1.6:0.2, Sn:Sb:Ni; and 98.2:1.6:0.1:0.1, Sn:Sb:Cu:Ni. During the immersion, drying, and heating of the electrode to a specific temperature, chlorides were transformed to an oxide coating layer to form Ti/SnO2–Sb2O3–CuO–NiO (TSCN), Ti/SnO2–Sb2O3–NiO (TSN), and Ti/SnO2–Sb2O3–CuO (TSC) anodes. The structural properties and surface morphologies of the products were investigated by atomic force microscopy (AFM), scanning electron microscope (SEM) and X-ray diffraction (XRD). The component of the coated layer was tested by energy dispersive spectroscopy (EDS), and the electrochemical performance was evaluated by cyclic voltammetry. In the present investigation, the batch electrochemical oxidation experiments were carried out using the three anodes and Cu/Zn cathode, at various operating parameters of, NaCl concentrations of 100, 200, 300, 400, 500, 1000, and 1500 ​mg/L, an initial ammonia concentration of 100 ​mg/L, a current density of 10 mA/cm2, and a pH of 7. Results revealed that the Ti electrode coated with the SnO2–Sb2O3–CuO anode had the highest anodic currents of 0.12 A, the smallest grain size of 40.76 ​nm, and the smallest crystal size of 18.1 ​nm. The results showed that after 60 ​min of electrolysis time, the coated electrode (TSC) possessed the best removal efficiency of 84.3% for the highest NaCl concentration studied of 1500 ​mg/L.

Virucidal Action Mechanism of Alcohol and Divalent Cations Against Human Adenovirus.

Hygiene and disinfection practices play an important role at preventing spread of viral infections in household, industrial and clinical settings. Although formulations based on >70% ethanol are virucidal, there is a currently a need to reformulate products with much lower alcohol concentrations. It has been reported that zinc can increase the virucidal activity of alcohols, although the reasons for such potentiation is unclear. One approach in developing virucidal formulations is to understand the mechanisms of action of active ingredients and formulation excipients. Here, we investigated the virucidal activity of alcohol (40% w/v) and zinc sulfate (0.1% w/v) combinations and their impact on a human adenovirus (HAdV) using, nucleic acid integrity assays, atomic force microscopy (AFM) and transmission electron microscopy (TEM). We observed no difference in virucidal activity (5 log10 reduction in 60 min) against between an ethanol only based formulation and a formulation combining ethanol and zinc salt. Furthermore, TEM imaging showed that the ethanol only formulation produced gross capsid damage, whilst zinc-based formulation or formulation combining both ethanol and zinc did not affect HAdV DNA. Unexpectedly, the addition of nickel salt (5 mM NiCl2) to the ethanol-zinc formulation contributed to a weakening of the capsid and alteration of the capsid mechanics exemplified by AFM imaging, together with structural capsid damage. The addition of zinc sulfate to the ethanol formulation did not add the formulation efficacy, but the unexpected mechanistic synergy between NiCl2 and the ethanol formulation opens an interesting perspective for the possible potentiation of an alcohol-based formulation. Furthermore, we show that AFM can be an important tool for understanding the mechanistic impact of virucidal formulation.

Neuroligin-2 dependent conformational activation of collybistin reconstituted in supported hybrid membranes

The assembly of the postsynaptic transmitter sensing machinery at inhibitory nerve cell synapses requires the intimate interplay between cell adhesion proteins, scaffold and adaptor proteins, and γ-aminobutyric acid (GABA) or glycine receptors. We developed an in vitro membrane system to reconstitute this process, to identify the essential protein components, and to define their mechanism of action, with a specific focus on the mechanism by which the cytosolic C terminus of the synaptic cell adhesion protein Neuroligin-2 alters the conformation of the adaptor protein Collybistin-2 and thereby controls Collybistin-2-interactions with phosphoinositides (PtdInsPs) in the plasma membrane. Supported hybrid membranes doped with different PtdInsPs and 1,2-dioleoyl-sn-glycero-3-{[N-(5-amino-1-carboxypentyl)iminodiacetic acid]succinyl} nickel salt (DGS-NTA(Ni)) to allow for the specific adsorption of the His6-tagged intracellular domain of Neuroligin-2 (His-cytNL2) were prepared on hydrophobically functionalized silicon dioxide substrates via vesicle spreading. Two different collybistin variants, the WT protein (CB2SH3) and a mutant that adopts an intrinsically ‘open’ and activated conformation (CB2SH3/W24A-E262A), were bound to supported membranes in the absence or presence of His-cytNL2. The corresponding binding data, obtained by reflectometric interference spectroscopy, show that the interaction of the C terminus of Neuroligin-2 with Collybistin-2 induces a conformational change in Collybistin-2 that promotes its interaction with distinct membrane PtdInsPs.

Oriented nanonetworks and submicron fibres of nickel as a conducting coating

Within the framework of the work, a methodology was developed for applying oriented nickel nanonetworks to glass, combined into a single system with an oriented network of submicron nickel fibres. The applying technique is original and has not been previously reported in the literature. The basis of the technique is precipitation from the liquid phase by chemical reduction of the nickel salt. The created coating could be interesting for the application in the transparent electrodes field.

Application of fungal laccase for heavy metals precipitation using tannin as a natural mediator

Nowadays, natural compounds have generated innovative attention for metal removal and precipitation; here, a fungus was isolated from soil samples in tannin media for metal removal. The isolate was identified as ‘Albifimbria viridisʼ by morphology and amplification of specific sequence. The isolate produced high activities of laccase when induced with tannin. The cell-free supernatant with 50 U/ml laccase activities could remove nickel, cobalt, cadmium, and copper nitrate salts by 59.69%, 59.75%, 46.97%, and 66.79%, respectively, while the precipitation of crude enzyme and metal salts by Fourier transform infrared spectroscopy analyses showed that only 2 metal salts (Cobalt and Copper nitrate) are precipitated in oxide form. Tannin was used as a mediator for metal removal, and the data were supported using a zymogram with partially purified laccase and metal precipitation on polyacrylamide gel electrophoresis. A 66 KDa laccase can remove metals and tannin. The metal interaction by this isolated compared with Phanerochaete chrysosporium and Aspergillus niger. All studied fungi could biodegrade the tannin as sole carbon source; however, for maximum activities, the new isolate Albifimbria viridis was selected in further study. The purified fungus in this study is a herbicide and has a high activity of laccase. The precipitation of metals by the enzyme of grown fungus in tannic acid is reported for the first time, which promoted the functional importance of this fungus.

Nickel/Cobalt‐Catalyzed Reductive Hydrocyanation of Alkynes with Formamide as the Cyano Source, Dehydrant, Reductant, and Solvent

AbstractA Ni/Co co‐catalyzed reductive hydrocyanation of various alkynes was developed for the production of saturated nitriles. Hydrocyanic acid is generated in situ from safe and readily available formamide. Formamide played multiple roles as a cyano source, dehydrant, and reductant for the NiII pre‐catalyst and vinyl nitriles, along with acting as the co‐solvent in this reaction. Detailed mechanistic investigation supported a pathway via hydrocyanation of C≡C bond and the subsequent reduction of C=C bond. Wide substrate scope, the employment of a cheap and stable nickel salt as pre‐catalyst, a safe cyano source and convenient experimental operation render this hydrocyanation practical for the laboratory synthesis of saturated nitriles.magnified image

Nickel-catalyzed aminocarbonylation of Aryl/Alkenyl/Allyl (pseudo)halides with isocyanides and H2O

Herein described is a nickel-catalyzed aminocarbonylation of aryl/alkenyl/allyl (pseudo)halides with isocyanides, providing aryl/alkenyl/allyl amides in 41% to 92% yields. Functional groups such as F, Cl, OMe, and heteroaromatic rings are compatible in the reaction. A Ni(0)/Ni(II) catalytic cycle is proposed based on preliminary experiments and previous literature. The reaction features readily available nickel salt, broad functional group tolerance, and simple reaction conditions.

Synthesis, Structure, and Biological Activity of Copper(II), Nickel(II), Cobalt(III), and Iron(III) Coordination Compounds with 2-{2-[(Prop-2-en-1-yl)carbamothioyl]hydrazinylidene}propanoic Acid

2-Oxopropanoic acid reacts in ethanol with N-(prop-2-en-1-yl)hydrazinecarbothioamide in a 1 : 1 mole ratio to form thiosemicarbazone H2L. Coordination compounds Cu(HL)X [X = Cl–, Br–, NO3–], Cu(H2O)(L), Ni(HL)2, Co(HL)2X [X = Cl–, Br–], and Fe(HL)2X [X = NO3–, Br–] are formed in the reactions of H2L with copper(II), nickel(II), cobalt(II), and iron(III) salts. The reactions of Cu(H2O)(L) with imidazole (Im) and 3,4-dimethylpyridine (3,4-Lut) result in mixed-ligand complexes Cu(A)(L) [A = Im, 3,4-Lut]. The structures of two copper complexes were determined by single crystal X-ray diffraction analysis. The synthesized complexes exhibit selective antimicrobial and antifungal activity in the concentration range of 15.62–1000 μg/mL. The introduction of amines into the inner sphere of copper complexes leads to an increase in the antimicrobial activity.

Modifying Effect of Low Salinity on Ni-Induced Alterations of the Lipid Composition in Mussels Mytilus edulis L.

The composition of lipids and fatty acids (FAs) in mussels Mytilus edulis exposed to various concentrations of nickel salt under reduced salinity of seawater (15‰) has been investigated. Alterations of the lipid composition in mussels in response to reduced salinity and the exposure to Ni have been observed. It is noted that changes in the content of phosphatidylserine and cholesterol and in phospholipid unsaturation in the gills and hepatopancreas of mussels under low salinity, most likely, indicate the development of pathological processes and activation of lipid peroxidation. Under normal salinity (25‰), similar changes in the lipid composition of the mussels studied have been observed at the initial stages of the experiment; however, by the end of the experiment, the phospholipid unsaturation is shown to be restored and the content of phosphatidylcholine increases.