Molten Salt Route Research Articles

Molten salt route of well dispersive barium titanate nanoparticles

Well dispersive barium titanate (BaTiO3) nanoparticles were synthesized by molten salt method using barium hydroxide octahydrate (Ba(OH)2·8H2O), titanium dioxide (TiO2), and the eutectic salts (NaCl–KCl) as raw materials. The as-prepared samples were characterized by X-ray diffraction, Fourier transform infrared spectrometry, UV–vis diffuse reflectance spectra, and field emission scanning electron microscopy. The present results show that BaTiO3 can be formed at low temperature of 600°C. The crystallinity of BaTiO3 increases with the temperature rising. SEM images clearly indicate that well dispersive BaTiO3 nanoparticles can also be successfully obtained even at high temperature of 800°C. Most BaTiO3 nanoparticles display hexagonal outline in shape. The average size of BaTiO3 nanoparticles is around 50nm. Meanwhile, compared with crystalline TiO2, amorphous TiO2 is favorable for the formation of BaTiO3, especially decreasing other undesired phases. In the end, the formation mechanism of well dispersive BaTiO3 nanoparticles is proposed for this molten salt system. Well dispersive BaTiO3 nanoparticles begin to show some sintering ability at low temperature of 900°C.

Partially inverse spinel ZnFe2O4 with high saturation magnetization synthesized via a molten salt route

Materials with high saturation magnetization (Ms) is greatly demanded in modern soft magnetic applications. In this work, we synthesized partially inverse spinel ZnFe2O4 in micron scale with the highest Ms (Ms = 5.05 μB) among ferrites. What’s more, it exhibits high Curie temperature (640 K), high resistivity, and excellent thermo-stability. Through careful analyses, including Mössbauer spectroscopic, x-ray diffraction, and x-ray photo-electron spectroscopic measurements, it was concluded that the strong ferromagnetism of the as-prepared ZnFe2O4 resulted from its partially inverse spinel structure. These excellent properties indicate the as-prepared ZnFe2O4 is an ideal kind of soft magnet.

Molten salt synthesis of LiGd0·01Mn1·99O4 using chloride–carbonate melt

Gadolinium substituted LiMn2O4 powders have been synthesised by molten salt route for application in lithium batteries. The thermal behaviour of precursor salts has been studied using thermogravimetry and differential thermal analyses. The formation of the compound is in the temperature range of 600–700°C. X-ray powder diffraction pattern confirms the presence of single phase cubic structure of LiGd0·01Mn1·99O4. The lattice parameter is found to be a = 8·2539 Å. The stretching vibrations of the metal cations are determined from the Raman spectrum. The stretching vibration frequency of the MnO6 bond decreases since the atomic mass of Gd3+ ions is higher than that of Mn3+ ions. The paramagnetic behaviour of the compounds was investigated by electron paramagnetic resonance spectroscopy. The electron paramagnetic resonance spectrum shows a narrow signal centred at g = 2·0. The morphological features of the powders were examined using scanning electron microscopy. It reveals that the average particle size of LiGd0·01Mn1·99O4 is found to be 5–10 μm.

A Two Step Synthesis Route of WC Nanopowders

Here, a novel molten salt route to synthesize ceramic WC nanopowders was presented. Compared to the traditional synthesis procedures, this method is relatively low cost involving two-step synthesis route. In the argon atmosphere at 650 oC, the powders were the mixed WC and W2C phases. These synthesized powders were transferred to a small crucible (30 mL) containing molten salt, which were put into a 500 mL crucible with some carbon powder in it as reducing atmosphere, followed by maintaining the reaction temperature at 1100 °C for 1 h. The phase purity and composition were characterized by the powder X-ray diffractometer (XRD). It was found that W2C was transformed thoroughly into WC, which indicated the successful synthesis of WC powders using this method. The mechanism of the reaction process in molten salt has been discussed finally. The thermogravimetric analysis indicated that the as-prepared samples showed good thermal stability and oxidation resistance in high temperature. The methodology reported in this work was fundamentally important, which may find potential industrial applications.

SnO2–NiO–C nanocomposite as a high capacity anode material for lithium-ion batteries

Carbon-coated SnO2–NiO nanocomposite was successfully synthesized via the molten salt route, using SnCl2·H2O and NiCl2·6H2O as the starting materials, with a molten salt composition of H2O2 : LiOH·H2O : LiNO3 as a solvent at 300 °C. The synthesis was followed by a carbon layering process. The phases and morphology of the as-prepared samples were examined by X-ray diffraction and transmission electron microscopy. Electrochemical investigation was carried out by using a series of complementary techniques, including galvanostatic charge–discharge, cyclic voltammetry, and impedance spectroscopy. The results confirmed that the carbon-coated SnO2–NiO nanocomposite has higher discharge capacity, better rate capability, and excellent cycling performance in comparison to the uncoated SnO2–NiO nanocomposite. The carbon-coated SnO2–NiO nanocomposite electrode exhibited a reversible capacity of about 529 mA h g−1 at 800 mA g−1, and 265 mA h g−1 at 1600 mA g−1, even after 500 cycles. The excellent electrochemical performance of the SnO2–NiO–C nanocomposite can be mainly attributed to the combined effects of the nanostructure, the carbon layering on the SnO2 and NiO nanoparticles, and the ultra-fine carbon matrix, because the three factors would contribute to high electronic conductivity, reduce the traverse time of electrons and lithium ions, and also prevent high volume expansion during cycling. Due to its excellent electrochemical performance, the SnO2–NiO–C nanocomposite could be considered as a promising anode material for future lithium-ion batteries to be used in electric vehicles and hybrid electric vehicles.

Long single-crystalline α-Mn2O3 nanowires: facile synthesis and catalytic properties

Single crystal α-Mn2O3 nanowires were prepared through a simple one-pot molten salt route. The as-prepared samples were characterized by XRD, TEM, SEM, HR-TEM and other techniques. The α-Mn2O3 nanowires display high aspect ratios with diameter about 10–50 nm and length about 20 μm. The formation mechanism was also investigated based on the time-dependent experiments. The prepared Mn2O3 nanowires exhibit excellent catalytic performance on the catalytic oxidation of CO.

Synthesis and optical properties of high-purity CoO nanowires prepared by an environmentally friendly molten salt route

CoO nanowires with diameters of 50 _80 nm, and lengths of up to more than 5 μm have been successfully synthesized by a simple environmentally friendly molten salt route, in which the precursor CoCO 3 nanoparticles are decomposed to form high-purity CoO nanowires in NaCl flux. The structure features and morphology of the as-prepared CoO nanowires were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), and selected area electron diffraction (SAED). The chemical composition and oxidation state of the prepared nanowires were systemically studied by X-ray photoelectron spectra (XPS) and laser Raman spectroscopy. The results indicated that the as-prepared CoO nanowires were composed of pure cubic CoO phase. The growth mechanism of the synthesized nanowires was also discussed in detail based on the experimental results.

Large-Scale Preparation and Catalytic Properties of One-Dimensional α/β-MnO2Nanostructures

One-dimensional α- and β-MnO2 single-crystalline nanostructures were prepared by the molten salt route. Both α- and β-MnO2 nanostructures exhibited large aspect ratios with diameters of tens of nanometers and lengths as long as several micrometers. The formation mechanism of α/β-MnO2 nanostructures was proposed on the basis of the time-dependent experiments. In addition, the as-prepared α- and β-MnO2 nanostructures showed excellent catalytic performance in the Fenton-like reaction.

Molten salt synthesis of LaF3:Eu3+ nanoplates with tunable size and their luminescence properties

A molten salt route to LaF3:Eu3+ nanoplate with tunable size was developed and the products were characterized by the X-ray diffraction (XRD), transmission electron microscopy (TEM), field-emission scanning electron microscopy (FE-SEM) and high-resolution TEM (HR-TEM). It is found that the nanoplates with different sizes (ca. 46, 20, and 12 nm) could be obtained when the molar ratio of the reagents NH4F and La(NO3)3 · 6H2O was adjusted. The possible formation process of reaction was discussed, and the reasonable mechanism of size controlling was also proposed. Furthermore, the luminescent properties of all the samples with different sizes and doping levels were investigated at room temperature.

Syntheses of Nano/Submicrostructured Metal Oxides with All Polar Surfaces Exposed via a Molten Salt Route

In this paper, a general method for the preparation of metal oxides with all polar surfaces exposed is presented. The syntheses of the products were carried out with simply performing reactions in a molten salt system, in which cations and anions tend to have strong electrostatic interactions with positive or negative charged polar planes so as to lower the surface energy and slow down the growth rate of polar planes, resulting in the formation of exposed polar surfaces. With this strategy, wurtzite structured ZnO, rocksalt structured MgO, spinel structured Co3O4, and ternary element compound ZnFe2O4 of spinel structure were successfully synthesized with all polar surfaces exposed, which demonstrated a universality of our proposed strategy.

Nanostructured nickel ferrite: A liquid petroleum gas sensor

The present investigation deals with the synthesis of nanostructured nickel ferrite (NiFe 2O 4) and their liquid petroleum gas-sensing characteristics. The 15–20 nm size nickel ferrite has been synthesized at 700 °C by a simple molten-salt route using sodium chloride as grain growth inhibitor. These nanoparticles exhibit significantly high response towards liquid petroleum gas (LPG) in comparison with ethanol vapor, hydrogen sulfide, ammonia and hydrogen. The gas response towards various gases at their 200 ppm concentrations is investigated at 200–450 °C. Different characterization techniques have been employed, such as differential thermal analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM) to study the crystallite size, structure and morphology. The results suggest possibility of utilization of the nanostructured nickel ferrite, without addition of any precious metal ion, as the LPG detector.

Facile synthesis and high d33 of single-crystalline KNbO3 nanocubes

Single-crystalline KNbO(3) nanocubes with orthorhombic phase were prepared in a large scale by a simple one-step molten salt route without using any surfactant as template; the nanostructures exhibited high piezoelectric properties such as d(33)=105 pC/N and k(p)=0.34 as piezoelectric materials.

Facile Preparation and Electrochemical Properties of Cubic‐Phase Li4Mn5O12 Nanowires.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Some Steps on the Molten Salt Route

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Preparation of α-MnO2 Nanorods and Co3O4 Submicrooctahedrons by Molten Salt Route

Abstract α-MnO2 nanorods and Co3O4 submicroctahedrons have been obtained by simple molten salt preparation route using cheap reagents. Particle size and morphology of the powders were studied by transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM).

Synthesis of Nanocrystalline ZnWO4 via Molten Salt Route and Its Photoluminescence.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Facile preparation and electrochemical properties of cubic-phase Li4Mn5O12 nanowires

Single crystalline Li4Mn5O12 nanowires with cubic phase were prepared in a large scale by a simple molten salt route without using any surfactant as template; the nanowires exhibited high storage capacity and coulombic efficiency as cathode materials for lithium-ion batteries.

A facile molten salt route to K 2Nb 8O 21 nanoribbons

Single-crystalline K 2Nb 8O 21 nanoribbons with width of 100–500 nm and thickness of ca. 30 nm, and length up to tens of micron, have been successfully synthesized by simply calcining Nb 2O 5 powders in molten KCl, and characterized with XRD, SEM, SEM, HRTEM and selected-area electron diffraction technique. The growth direction of the obtained K 2Nb 8O 21 nanoribbons was determined to be the 〈1 0 0〉 crystallography direction.

Synthesis of Nanocrystalline ZnWO4 via Molten Salt Route and Its Photoluminescence

Abstract ZnWO4 nanocrystalline powder has been synthesized by the molten salt route using KNO3/NaNO3 mixture as reaction media. Pure ZnWO4 phase was obtained at 250 °C for 2 h without any intermediate phase. Particle size and morphology of the powder were studied by transmission electron microscopy (TEM). The luminescent properties of the final powder as functions of the reaction temperature and time have been studied.

Optical Properties of the Perovskite Solid Solution LaTiO2N—ATiO3 (A: Sr, Ba).

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.