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Sobhani A.,Kosar University of Bojnord | Salavati-Niasari M.,University of Kashan
Journal of Alloys and Compounds | Year: 2014

The cubic MnSe2/Se nanocomposites were produced under hydrothermal condition, by reduction of SeCl4 to Se and Se 2-, and reaction of the reduced selenium with Mn2+ ion during the next step, in the presence of different surfactants using hydrazine as reductant. The main factors affecting the morphology, the particle size and the phase of the products, such as surfactant, reductant and its amount, reaction temperature and time were studied. The pure Se or a mixture of Se and MnSe2 nanorods were obtained in the presence of different surfactants and small amounts of hydrazine. The cubic MnSe2/Se nanocomposites were formed at 120 °C for 12 h or longer periods of time, in the presence of polyethylene glycol (PEG) and large amounts of hydrazine. The size of the as-prepared cubes decreases with increasing the reaction time. With increasing temperature of reaction from 120 °C to 180 °C, the morphology of the products changes from cubes to the mixture of nanorods and nanoparticles. © 2014 Elsevier B.V. All rights reserved. Source


Sobhani A.,Kosar University of Bojnord | Salavati-Niasari M.,University of Kashan
Journal of Materials Science: Materials in Electronics | Year: 2016

In this article, the synthesis and characterization of Co2P/Co nanocomposites are reported. Three kinds of precursors are studied: bis(salicylidene)cobalt(II) [Co(sal)2], bis(salicylate)cobalt(II) [Co(Hsal)2] and cobalt oxalate [Co(O4C2)·4H2O]. The cobalt(II) acetate tetrahydrate Co(CH3COO)2·4H2O is used as reference. The nanocomposites are prepared by thermal decomposition method using triphenylphosphine as a surfactant solvent and phosphorus precursor. A possible mechanism of the formation of the nanocomposites is put forward to explain the experimental observations. This is the first time that Co2P/Co nanocomposites are synthesized. To study the crystalline structure, composition, size, morphology and magnetic property of the products, characterization techniques including XRD, SEM, TEM, FT-IR and VSM are employed. © 2015, Springer Science+Business Media New York. Source


Sobhani A.,Kosar University of Bojnord | Salavati-Niasari M.,University of Kashan
Journal of Alloys and Compounds | Year: 2014

FeSe2 nanoparticles and FeSe2/FeO(OH) nanocomposites have been synthesized through a novel controllable hydrothermal method with FeSO4·7H2O and SeCl4 as precursors. In this procedure, H2SeO3 (obtained from aqueous solution of SeCl4) is gradually reduced to Se and Se2- by reductant. The reduced Se and Se2- ions are combined with Fe2+ ion to give FeSe2. By varying the surfactant, reaction time, temperature, reductant and amount of hydrazine hydrate (N2H4·H2O), the method permits us to synthesize different products. The FeSe2 nanoparticles are synthesized in the presence of PEG4000 at 140 °C for 13 h. Using PEG600 (at 140 °C or 110 °C for 13 h) and sodium dodecyl sulfate (at 140 °C for 7 h), FeSe2/FeO(OH) nanocomposites are synthesized. SEM and TEM images show the morphology and size of the as-synthesized samples. Chemical composition of the samples is characterized by XRD, XPS and EDS. Ultraviolet-visible and photoluminescence spectra exhibit optical properties of nanostructures. Magnetization measurement shows a twofold behavior, ferromagnetic and paramagnetic behaviors, for FeSe2 nanoparticles. © 2014 Elsevier B.V. Source


Sobhani A.,Kosar University of Bojnord | Salavati-Niasari M.,University of Kashan
Journal of Materials Science: Materials in Electronics | Year: 2016

Nickel phosphide nanostructures were prepared by thermal decomposition method from different inorganic precursors, such as: bis(salicylidene)nickel(II) [Ni(sal)2], bis(salicylate)nickel(II) [Ni(Hsal)2], nickel oxalate [Ni(O4C2)(H2O)4] and nickel-o-phthalate [Ni(pht)(H2O)2]. Nickel(II) acetate tetrahydrate Ni(CH3COO)2·4H2O was used as reference. Nanostructural control of products prepared through the thermolysis of precursors using triphenylphosphine as a surfactant solvent and phosphorus precursor was reported. The SEM and TEM images show the morphology and particle size of the as-synthesized nanostructures. The XRD patterns show mixed-phase hexagonal Ni2P/tetragonal Ni12P5 (represented as NixPy). The FT-IR spectroscopy confirms that the products prepared are NixPy phase, which is in agreement with XRD results. © 2015, Springer Science+Business Media New York. Source


Sobhani A.,Kosar University of Bojnord | Salavati-Niasari M.,University of Kashan
Ceramics International | Year: 2014

In this paper copper selenide nanostructures were synthesized via a simple hydrothermal method based on the reaction between copper salt and SeCl 4 in water. The reduction reaction of SeCl4 to Se and then Se2- was carried out by three types of reductants: N 2H4.H2O, KBH4, and metallic Zn. Different compositions of copper selenides were obtained by changing the molar ratio of the precursors. At the temperature of 120 °C for a 12 h period of time, when the molar ratio of Cu/Se is 1:1 or 2:1, the product is pure and found to be CuSe and Cu1.8Se, respectively. A mixture of the different phases of copper selenides is obtained by making use of 1:2, 3:2 and 3:1 M ratios between Cu and Se. With an increasing reaction temperature up to 210 °C, the mixture of Cu3Se2 and CuSe is prepared from 1:1 M ratio of precursors. The effects of copper salt, surfactant, amount of hydrazine, reaction time and temperature on the morphology and particle size of products are also investigated. The synthesis can be performed conveniently and safely. The products are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS) analysis. Photoluminescence (PL) is used to study the optical property of copper selenides. © 2014 Elsevier Ltd and Techna Group S.r.l. Source

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