Synthesis of nickel sulfide and nickel–iron sulfide nanoparticles from nickel dithiocarbamate complexes and their photocatalytic activities

[ Ni(dtc)₂] (dtc = N-(pyrrole-2-ylmethyl)-N-thiophenemethyldithiocarbamate ( 1 ), N-methylferrocenyl-N-(2-phenylethyl)dithiocarbamate ( 2 ), N-furfuryl-N-methylferrocenyldithiocarbamate ( 3 ), and (N-[pyrrole-2-ylmethyl]-N-thiophenemethyldithiocarbamato-S,S′)(thiocyanato-N)(triphenylphosphine)nickel(II) ( 4 ) complexes were prepared and characterized by elemental analysis, infrared, ultraviolet–visible, and nuclear magnetic resonance (¹H and ¹³C) spectroscopies. The data were consistent with the formation of square planar nickel(II) complexes, which was confirmed by single-crystal X-ray diffraction studies on 2 and 4 . Fe···Fe interactions exhibited by complex 2 led to supramolecular aggregation. The structure of 4 reveals intermolecular and intramolecular C-H···Ni anagostic interactions. The anion-sensing properties of 2 were studied with halide ions by cyclic voltammetry. It was observed that 2 acts as sensor for bromide. Complexes 1 , 2 , and 3 , were utilized to prepare nickel sulfide, nickel–iron sulfide-1, and nickel–iron sulfide-2, respectively. The composition, structure, morphology, and optical properties of nickel sulfide and nickel–iron sulfides were examined using powder X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray spectroscopy, ultraviolet–visible, fluorescence, and infrared spectroscopy. Powder X-ray diffraction patterns of nickel sulfide, nickel–iron sulfide-1, and nickel–iron sulfide-2 indicate the formation of orthorhombic Ni₉S₈, cubic NiFeS₂, and cubic Ni₂FeS₄, respectively. The photocatalytic activities of as-prepared nickel sulfide and nickel–iron sulfide-1 nanoparticles were investigated for photodegradation of methylene blue and rhodamine-B under ultraviolet irradiation. Nickel–iron sulfide-1 nanoparticles show slightly higher photodegradation efficiency compared with the nickel sulfide nanoparticles.     

Electrodeposition of iron–molybdenum–tungsten coatings from citrate electrolytes

Specific features of the electrodeposition of iron–molybdenum–tungsten coatings from citrate electrolytes based on iron(III) sulfate in the dc mode and with a unipolar pulsed current were studied. It was shown that varying the relative concentrations of salts of alloy-forming metals and the solution pH makes it possible to obtain lustrous compact coatings with low porosity and various contents of high-melting components. The effect of temperature on the coating composition and current efficiency was examined. The current density ranges providing high electrolysis efficiency were found and it was demonstrated that using a pulsed current favors formation of more compositionally homogeneous surface layers at a smaller amount of adsorbed nonmetallic impurities in the coatings. The iron–molybdenum–tungsten coatings are X-ray-amorphous and have better physicomechanical properties and corrosion resistance as compared with the base, which makes it possible to recommend these coatings for application in techniques for surface reinforcement and restoration of worn-out articles.     

Electrodeposition kinetics of tin—antimony alloy from sulfate electrolyte with organic additives

Kinetics of the Sn-Sb alloy electrodeposition from sulfate electrolytes containing organic additives (syntanol DS-10, Formalin, 1,4-butynediol) is studied by the faradaic impedance method. Bright Sn-Sb alloy coatings are plated in this electrolyte at i_c = 0.5-5 A/dm². With increasing i_c, the Sb content in the alloy decreases from 14 to 6.6 wt %     

Electrodeposition,properties, and composition of rhenium–nickel alloys

The process of deposition of the Re–Ni alloy, its current efficiency, and the alloy composition are studied as a function of the current density and the solution temperature. The hydrogen content in the deposits, their surface morphology, internal structure, and properties as the cathodic material for HER are examined. It is assumed that besides the high rhenium content, the high catalytic activity of nickel–rhenium alloys is associated with the high degree of their structural disordering.     

Thermomagnetometric analysis of nickel–zinc ferrites

Journal of Thermal Analysis and Calorimetry - In this paper, magnetic phase transitions of nickel–zinc ferrites (Ni1?xZnxFe2O4) with a zinc content of...     

Electrodeposition of Ni–Fe alloy from a choline chloride-containing ionic liquid

Journal of Solid State Electrochemistry - The electrochemical deposition of a nickel–iron alloy from a plating solution based on a deep eutectic solvent (a eutectic mixture of ethylene glycol...     

Synthesis and properties of zinc–nickel–carbon nanotube composite coatings

Composite electrochemical coatings modified with carbon nanotubes were produced on the basis of the zinc–nickel alloy. The functional properties (friction coefficient, protective capacity) of the composite coatings were studied in comparison with zinc–nickel alloys without a dispersed phase. It was found that, upon inclusion of carbon nanotubes particles into zinc–nickel deposits, their sliding friction coefficient decreases by a factor of 1.3–1.4 and the range of passive-state potentials becomes two times wider.     

FT-IR and thermal studies of iron–nickel–manganese ternary levo-tartrate crystals

Several metallic tartrates deserve special attention due to their various applications. In the present investigation, mixed tartrate crystals of three different metals are reported. Using single diffusion gel growth technique, iron–nickel–manganese (Fe–Ni–Mn) ternary levo-tartrate compound crystals were grown with different concentrations. Spherulitic crystals with different coloration were obtained for various concentrations of metals. The concentrations of metals were determined by EDAX. The presence of functional groups was confirmed using Fourier transform infrared (FT-IR) spectroscopy. The powder XRD study suggested that the crystals belong to the orthorhombic system. The thermal stability of all the samples was studied from room temperature to 900 °C. It was found that the composition of the crystal affects the dehydration and decomposition behaviors. The results are discussed.     

Synthesis and characterization of manganese–zinc ferrite obtained by thermal decomposition from organic precursors

Mn–Zn ferrites were obtained by the sol–gel autocombustion methods. The effect of the precursor used in the sol–gel autocombustion synthesis on the ferrite’s microstructure was examined. The as-obtained powders were characterized by XRD, FTIR, SEM, and TG/DTA. All ferrite powders obtained from different organic precursors, after gel autocombustion, were pure spinel phase, without secondary phases. The average crystallite size, estimated from Scherrer equation, was the smallest for ferrite obtained from a mixture of fuels/precursors (citric acid and EDTA). This ferrite powder has sponge-like microstructure with large pores, but it is less agglomerated than the material obtained from glycine as the fuel.     

Electrodeposition of Zn–Ni–P compositionally modulated multilayer coatings: An attempt to deposit Ni–P and Zn–Ni alloys from a single bath

The effects of bath composition and deposition variables on the electrodeposition of Zn–Ni–P alloys were studied in order to develop a single bath for deposition of Ni–P/Zn–Ni compositionally modulated multilayer coatings (CMMCs). The basis for development of the bath was a large increase in the Ni deposition rate compared to that of Zn at low deposition overpotentials combined with the impossibility of codeposition of Zn with P. EDS analysis demonstrated that the deposits obtained from the Zn–Ni–P bath at low overpotentials were practically all Ni–P, while the alloy deposited at high overpotentials was mainly Zn–Ni with around 3.2 wt% P content.     

Synthesis and characterization of activated carbon@zerovalent iron–nickel nanoadsorbent for highly efficient removal of Reactive Orange 16 from aqueous sample: experimental design,kinetic, isotherm and thermodynamic studies

Research on Chemical Intermediates - A simple and fast method based on activated carbon@nanozerovalent iron–nickel (AC@nZVI/Ni) nanoadsorbent was developed for highly efficient removal of...     

Anomalous codeposition of cobalt and ruthenium from chloride–sulfate baths

Codeposition of Ru and Co was studied at room temperature and at 50 °C with various Ru³⁺ and Co²⁺ concentrations in the electrolyte. The codeposition of Co and Ru proved to be anomalous since no pure Ru could be obtained in the presence of Co²⁺ in the electrolyte, but a significant Co incorporation into the deposit was detected at potentials where the deposition of pure Co was not possible. The composition of the deposits varied monotonously with the change of the concentration ratio of Co²⁺ and Ru³⁺. The deposition of Ru was much hindered, and the current efficiency was a few percent only when the molar fraction of Co in the deposit was low. Continuous deposits could be obtained only when the molar fraction of Co in the deposit was at least 40 at.%. The deposit morphology was related to the molar fraction of Co in the deposit. The X-ray diffractograms are in conformity with a hexagonal close-packed alloy and indicate the formation of nanocrystalline deposits. Two-pulse plating did not lead to a multilayer but to a Co-rich alloy. Magnetoresistance of the samples decreased with increasing Ru content.     

Synthesis and characterization of sterically encumbered β-ketoiminate complexes of iron(II) and zinc(II)

The synthesis, structure, and spectroscopic signatures of a series of four-coordinate iron(II) complexes of β-ketoiminates and their zinc(II) analogues are presented. An unusual five-coordinate iron(II) triflate with three oxygen bound protonated β-ketoimines is also synthesized and structurally characterized. Single-crystal X-ray crystallographic analysis reveals that the deprotonated bis(chelate)metal complexes are four-coordinate with various degrees of distortion depending on the degree of steric bulk and the electronics of the metal center. Each of the high-spin iron(II) centers exhibits multiple electronic transitions including ligand π to π*, metal-to-ligand charge transfer, and spin-forbidden d-d bands. The (1)H NMR spectra of the paramagnetic high-spin iron(II) centers are assigned on the basis of chemical shifts, longitudinal relaxation times (T(1)), relative integrations, and substitution of the ligands. The electrochemical studies support variations in the ligand strength. Parallel mode EPR measurements for the isopropyl substituted ligand complex of iron(II) show low-field resonances (g > 9.5) indicative of complex aggregation or crystallite formation. No suitable solvent system or glassing mixture was found to remedy this phenomenon. However, the bulkier diisopropylphenyl substituted ligand exhibits an integer spin signal consistent with an isolated iron(ii) center [S = 2; D = -7.1 ± 0.8 cm(-1); E/D = 0.1]. A tentative molecular orbital diagram is assembled.     

Catalytic properties of nickel–yttrium mixed oxides and the influence of ionizing radiation

Some physico-chemical and catalytic properties of NiO–Y₂O₃ cataysts containing various amounts of components in the range 0–100 wt% of one component have been studied before and after 1 MGy gamma or accelerated electron irradiation in air or in water using the hydrogen peroxide decomposition as a test reaction. Both kinds of irradiation led only to a change in surface oxidative ability but did not lead to modification of the catalytic activity of the catalysts. The reduction of the catalysts led to a creation of new kind of catalytic sites.     

Hollow nanodendritic nickel oxide networks prepared by dealloying of nickel–copper alloy

Three-dimensional hollow nanorod network of nickel has been produced by a dealloying process of the electrodeposited nickel–copper alloy with nanodendritic structure. The nanostructured nickel was subsequently heat treated to form the nickel oxide with little change in the original structure. The resulting sample was tested as the high rate anode in a rechargeable lithium battery. It shows the exceptional rate capability, far exceeding that of the counterpart of nickel–copper oxide network with normal solid branches: reversible capacity at the rate of 20.9 A g^?1 is approximately 70 % of the capacity at 0.26 A g^?1 rate.     

Iron–cobalt and iron–cobalt–nickel nanowires deposited by means of cyclic voltammetry and pulse-reverse electroplating

Metal nanowires composed of Fe–Co and Fe–Co–Ni alloys were successfully prepared by means of cyclic voltammetry (CV) and pulse-reverse (PR) electroplating techniques from acidic metal chloride solutions. The anodic dissolution process in the CVs or in the reverse electroplating period was found to be the key factor influencing the formation of metal nanowires. The addition of nickel into the Fe–Co alloy was found to extend the diameter of these nanowires. The morphology and crystalline information of these alloy deposits prepared by CV and PR deposition techniques were obtained from the field-emission scanning electron microscopic (FE-SEM) photographs and X-ray diffraction (XRD) patterns, respectively.     

Nanocrystalline structure and soft magnetic properties of nickel–molybdenum alloy thin films electrodeposited from acidic and alkaline aqueous solutions

Nanocrystalline nickel–molybdenum (Ni–Mo) alloy thin films were electrochemically synthesized in acidic and alkaline aqueous solutions. Transmission electron microscope bright-field images and electron diffraction patterns of the electrodeposits made it obvious that pure Ni consists of a submicron crystalline phase with the grain diameter of several hundred nanometers, while Ni–20 %Mo alloy was composed of a nanocrystalline phase with the grain diameter of a few nanometers. It was estimated that the nanocrystalline phase of electrodeposited Ni–Mo alloy thin films was introduced by the formation of supersaturated Ni–Mo solid solution phase with Mo content in the deposit more than 20 %. Submicron crystalline pure Ni thin films were hardly magnetized in perpendicular direction to the film plane while the nanocrystalline Ni–20 %Mo alloy thin films were isotropically magnetized. It was suggested that the isotropical magnetization behavior was caused by decreasing the demagnetizing field and the magneto crystalline anisotropy with a decrease in the magnetic moment and the average crystal grain size. Coercive force of a submicron crystalline pure Ni thin film electrodeposited from an acidic aqueous solution was ca. 100 Oe while that of a nanocrystalline Ni–20 %Mo alloy thin film electrodeposited from an alkaline aqueous solution was only 1～2 Oe. Soft magnetic properties of Ni–Mo alloy thin films electrodeposited from an alkaline aqueous solution were better than that from an acidic aqueous solution and it was improved with an increase in Mo content in the deposit. It was estimated that the electrodeposited Ni–Mo alloy catalysts could be easily recovered with magnetic field less than 1 kOe.