A NiS2 nanostructure with a protective layer of Ni(2+) and SO4(2-) ions around it has been successfully synthesized using the Ni(II)-Salen (Salen = N,N'-bis(salicylidene)ethylenediamine) complex via a simple solvothermal approach in the presence of anhydrous sodium thiosulfate (Na2S2O3) as sulfur source and stabilizer. Unexpectedly, no one kind of pure nickel sulfide nanostructure was prepared using the Ni(II)-Salophen complex or some of the simple mono and bidentate Ni(II) complexes as starting materials and the obtained products were a mixture of nickel sulfides. In the photoluminescence spectrum of the prepared NiS2, two peaks were evident at 400 and 420 nm with emission maxima, and one broad peak with emission minima was located at 800 nm. The as-synthesized NiS2 nanostructure displays a weak ferromagnetic behaviour at room temperature, which has small remanent magnetization and saturation magnetization compared to bulk NiS2. These changes might be attributed to the existence of a protective layer of nickel and sulfate ions around the NiS2 nanostructures that was confirmed by Energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared (FTIR) and Raman spectroscopy. The prepared nanostructure has been characterized structurally, electrochemically, optically and magnetically by available methods like X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Energy-dispersive X-ray spectroscopy, Fourier transform infrared and Raman spectroscopy, Cyclic voltammetry (CV), Photoluminescence (PL) spectroscopy and vibrating sample magnetometer (VSM).

A facile method is described for synthesizing quasi-cotton fiber and spherical nickel nanostructures via a thermal reduction of Ni(acac)2 (acac = acetylacetonate) in N,N-dimethylformamide (DMF) and in the presence and absence of sodium thiosulfate, respectively. XPS analysis revealed the existence of Ni(2+) and SO4(2-) ions on the surface of nickel nanostructures obtained in the presence of anhydrous sodium thiosulfate. Magnetic measurements of this sample resulted in lower values of saturation magnetization (2.5 emu g(-1)) and remanent magnetization (0.6 emu g(-1)) and higher value of coercivity (206 Oe), compared to nickel nanostructure in the absence of sodium thiosulfate. The effects of the temperature, type of reactant and mole ratio of S2O3(2-) : Ni(2+) on the phase structure obtained products were demonstrated.

The hydrogen storage capacity of a (0.04)Fe–Ag/TiO2/CNT electrode is 10.94 wt%, which is nearly 5 times higher than pristine MWCNTs.

CdS NPs and the GO–CdS nanocomposite with excellent optical and electrochemical properties were synthesized using a new method.

Stabilized nickel nanoparticles (SNNPs) were prepared using Ni(acac) 2 (acac = acetylacetonate) via a simple solvothermal method. The synthesis of the nickel nanoparticles was performed in the presence of sodium dodecyl sulphate (SDS) of different concentrations (mole ratios of SDS:Ni(acac) 2 = 1:1, 2:1 and 4:1), as the stabilizer, in order to appraise their influence on the morphology, size, dispersion, magnetic properties and electrochemical activity of the nickel nanoparticles. The synthesized products have been characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectra, energy-dispersive X-ray spectroscopy, vibrating sample magnetometry and electrochemical studies. It is noteworthy that the average particles size of the SNNPs has been reduced by increasing the SDS concentration, while at high concentration (mole ratio of SDS:Ni(acac) 2 = 4:1), the small particles tend to coalesce and create a big one. The stabilized Ni nanoparticles could be used as electrode materials for hydrogen evolution in alkaline medium. The electrochemical measurements demonstrated that the higher conductivity and lower value of faraday resistance of the as-prepared samples were when the mole ratio of SDS:Ni(acac) 2 was 2:1.