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In this work, we have developed a simple and facile method to synchronously synthesize hollow FeSe2/C nanospheres using the Kirkendall effect. When evaluated as an anode for SIBs, the hollow FeSe2/C nanospheres exhibit a high discharge capacity retention of 474.1 mA h g−1 at 0.05 A g−1 (based on the calculation of FeSe2), which is very close to the theoretical capacity of FeSe2 (∼500 mA h g−1). Meanwhile, hollow FeSe2/C also has a superior rate capability of 364.5 and 316.5 mA h g−1 even at 2.0 and 5.0 A g−1, respectively. The high performance of the hollow FeSe2/C nanospheres can be ascribed to the unique carbon coated hollow nanostructure. [ABSTRACT FROM AUTHOR]

For lithium-selenium batteries, commercial applications are hindered by the inferior electrical conductivity of selenium and the low utilization ratio of the active selenium. Here, we report a new baked-in-salt approach to enable Se to better infiltrate into metal-complex-derived porous carbon (Se/MnMC-B). The approach uses the confined, narrow space that is sandwiched between two compact NaCl solid disks, thus avoiding the need for protection with argon or a vacuum environment during processing. The electrochemical properties for both lithium and sodium storage of our Se/MnMC-B cathode were found to be outstanding. For lithium storage, the Se/MnMC-B cathode (with 72% selenium loading) exhibited a capacity of 580 mA h g−1 after 1000 cycles at 1 C, and an excellent rate capability was achieved at 20 C and 510 mA h g−1. For sodium storage, a specific capacity of 535 mA h g−1 was achieved at 0.1 C after 150 cycles. These results demonstrate the potential of this approach as a new effective general synthesis method for confining other low melting point materials into a porous carbon matrix. [ABSTRACT FROM AUTHOR]

Silicon (Si) nanoparticles have been prepared by a “metathesis” reaction of magnesium silicide (Mg2Si) and zinc chloride (ZnCl2) in an autoclave at 300 °C. The as-prepared Si nanoparticles exhibit a reversible capacity of 795 mA h g−1 at a current density of 3.6 A g−1 over 250 cycles. [ABSTRACT FROM AUTHOR]

High purity FeO/helical carbon nanofiber composites were obtained on a large scale by the catalytic pyrolysis of ferrocene in the presence of tin powder at 500°C over 12 h. The sizes of FeO nanoparticles are 35-65 nm in size, and the diameters of the helical carbon nanofibers range from 40-70 nm. The shapes and compositions of the nanocomposites are simply controlled by adjusting the reaction temperatures. On the basis of the obtained experimental results the formation of the helical FeO/carbon nanofiber composites was investigated and discussed. The magnetic hysteresis loop of the products shows ferromagnetic behavior with saturation magnetization ( M), remanent magnetization ( M) and coercivity ( H) values of ca. 29.8 emu/g, 9.6 emu/g and 306.6 Oe, respectively. [ABSTRACT FROM AUTHOR]

α-silicon nitride nanorods have been synthesized through solid-state reduction–nitridation of silica using NaNH2 as both a reductant and a nitriding reagent. X-ray powder diffraction patterns show that the products have a hexagonal phase with lattice parameters a=7.767 Å and c=5.630 Å. Transmission electron microscopy reveals that the as-synthesized products are pure nanorods with an average size about 30 nm in diameter and 400 nm in length. X-ray photoelectron spectra indicate that the molar ratio of Si/N is 2.988:4. Fourier-transform infrared spectrum yields a strong Si–N absorption at 926 cm−1 that may be a red shift due to size effect. [ABSTRACT FROM AUTHOR]

X-ray powder diffraction and high-resolution transmission electron microscopy (HRTEM) have found coexistence of three structures of GaN: wurtzite, zinc blende, and rocksalt in the samples prepared through benzene thermal process at 280–300 °C under pressure about 5 MPa. Previously, GaN with rocksalt structure only appeared at high pressure more than 37 GPa. HRTEM showed that there was a transitional region between the two cubic phases of GaN with zinc blende and rocksalt. X-ray photoelectron spectra analysis of the sample gave the average composition of Ga0.95N. © 1996 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Abstract: Large-scale Mn2O3 homogeneous core/hollow-shell structures with cube-shaped and dumbbell-shaped morphologies have been synthesized trough a facile and low-cost method. The microscopy analyses indicate that the core-shell microcubes have an average edge length of 2.5μm with a shell thickness of about 150nm, and the core-shell microdumbbells were formed with a length of about 3μm and shell thickness of about 160nm. The possible formation mechanism was discussed on the basis of transmission electron microscopy observations. The novel homogeneous core/hollow-shell structures were found to exhibit excellent performance in wastewater treatment. [Copyright &y& Elsevier]

Nowadays, gas sensors are playing an essential role in wearable electronic devices for detecting pollutant, flammable, toxic gases besides it needs to be flexible, transparent, and operating at room temperature. Liquefied petroleum gas detection is critical because it is a flammable and toxic gas that of dangerous to humans as well the environment. The present study reports the hydrothermally synthesized MgO@CeO2 nanocomposite coated on flexible Polyethylene terephthalate substrate printed interdigitated gold electrodes (working electrodes) through the spin coating and continued for liquefied petroleum gas detection (50–900 ppm) at room temperature. X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy and transmission electron microscopy were used to analyze the structural and morphological studies of prepared nanomaterials. The fabricated low-cost, eco-friendly MgO@CeO2 chemiresistive flexible sensor showed good selectivity towards analyte at room temperature with a sensitivity of 32% at 900 ppm and lower detection of 5% towards 50 ppm along with good long-term stability and mechanical flexibility. [ABSTRACT FROM AUTHOR]

Abstract: Well dispersed MnCO3/carboxylated carbon nanotube (CNT) nanocomposites are prepared by a facile solution precipitation method. Transmission electron microscopy (TEM) characterizations show that due to heterogeneous nucleation sizes the addition of carboxylated CNT is able to suppress growth of MnCO3 particles, resulting in formation of nano-sized particles. Electrochemical characterization of lithiation/delithiation of the MnCO3/CNT nanocomposites reveals a large capacity of 772mAhg−1 for the first cycle with 84% capacity retention after 100 cycles. The superior electrochemical performance of the MnCO3/CNT nanocomposites electrode compared to the pure MnCO3 electrode can be attributed to super-fine particles and good conductivity due to the presence of CNTs. Their large surface area facilitates fast lithium ion and electron transport and accommodates the big volume change during the conversion reactions. [Copyright &y& Elsevier]

Abstract: Honeycomb-like graphitic macroporous carbon (HGMC) was synthesized by means of pyrolysis of NH4HCO3 using Mg powder as reductant in an autoclave at 550°C. The characterization of structure and morphology was carried out by X-ray diffraction (XRD), Raman spectrum, field-emission scanning electron microscopy (FESEM), and (High-resolution) transmission electron microscope [(HR)TEM]. The results of nitrogen adsorption–desorption indicate that the products are macropore materials with the pore size of 1–3μm, and the Brunauer–Emett–Teller (BET) surface area was 14m2/g. As a typical morphology, the possible growth process of HGMC was also investigated and discussed. The experimental results show that the in situ formed MgO microparticles play a template role during the HGMC formation. [Copyright &y& Elsevier]

Abstract: Cubic phase silicon carbide (3C-SiC) nanowires (labeled as “Sample 1”) with diameters ranging from 10nm to 80nm and lengths up to several micrometers were obtained by using CHI3, Si powder, and metallic Na as reactants at 230°C. In addition, SiC polyhedra (labeled as “Sample 2”) with smooth surfaces and diameters of 2–5μm were obtained by using the different amounts of the same reactants at 500°C. The room-temperature photoluminescence (PL) spectra of Sample 1 and Sample 2 show strong ultraviolet emission peaks centered at 360nm and 354nm, respectively. Thermal gravimetric analysis (TGA) curves reveal that the thermal stability (against air oxidation) of Sample 2 is better than Sample 1. The possible formation mechanisms of the products with distinct dimensions were briefly discussed. [Copyright &y& Elsevier]

Abstract: Silicon carbide (3C-SiC) nanocrystals were prepared starting from SiO2, C2H5OH, and metallic Mg in an autoclave at 200°C. X-ray diffraction patterns of the sample can be indexed as the cubic phase of SiC with the lattice constant a =4.357Å, in good agreement with the reported value (JCPDS card no. 29-1129; a =4.359Å). Transmission electron microscopy images show that the product mainly composed of nanowires with diameters in the range of 10–30nm and lengths up to tens of micrometers; High-resolution transmission electron microscopy images reveal that these 3C-SiC nanowires grow along [111] direction; As polyvinylpyrrolidine was added into the above reactant system, the final products obtained at 180°C were mixed 3C and 2H-SiC flakes. Thermal gravimetric analysis curves reveal that these two samples have thermal stability below 800°C, and room-temperature photoluminescence spectrum of the 3C-SiC sample show a strong emission peak centered at 403nm. [Copyright &y& Elsevier]

Abstract: Hexagonal boron nitride (h-BN) particles including hollow spheres (with a proportion of ~30–40%) and nanotubes (10%) have been synthesized by using sodium fluoroborate and sodium azide at 450°C for 20h. X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) studies show that the as-obtained BN hollow particles are crystalline. The total specific surface area of the product calculated from Brunauer–Emmentt–Teller (BET) absorption measurement is 89.79m2/g, indicating that it may be utilized as a promising candidate for hydrogen storage container or catalyst. Thermal gravimetric analysis (TGA) result reveals its excellent thermal stability below 800°C. Its possible growth mechanism and the effects of reaction parameters were also briefly discussed. [Copyright &y& Elsevier]

Copper microparticles (2−5 um) encapsulated in carbonaceous shell polyhedral composites were mildly prepared via a one-pot hydrothermal process using copper nitrate, glucose, and sodium citrate at 150 °C, in which the glucose was found to play reducer and graphite source roles during the formation of these core−shell-like composites. Thermal stability results indicated that their weights remain almost unchanged below 240 °C in ambient atmosphere. It is interesting that the copper microparticles could be partially released out and translated into monodisperse Cu nanoparticles around the initial composites under the convergent electron beams in a transmission electron microscope (TEM). This phenomenon is an appealing discovery, which might endow the Cu@C composite with new functions; for example, it might be applied as a sensitive detector for the leakage of electron beams or other substances for the sake of being a safeguard. In addition, the corresponding hollow carbonaceous polyhedra were also obtained after the acid treatment, which might be used as a template to fabricate other kinds of polyhedra. [ABSTRACT FROM AUTHOR]

Abstract: Bismuth sulfide nanorods were synthesized on a large scale via a simple self-sacrificing template route, by the direct reaction between the pre-prepared precursor metallic bismuth NT arrays and thiourea (Tu) in air at 100 ∘C for 16 h. XRD, TEM, SEM and HRTEM characterizations show that the prepared Bi2S3 samples are all phase pure and the Bi2S3 nanorods have uniform diameters of approximately 30–50 nm and lengths up to several micrometers. [Copyright &y& Elsevier]

Abstract: Uniform bismuth selenide hollow nanospheres were synthesized on a large scale in a mixed solvent of ethylene glycol (EG) and oleic acid (OA). The diameter of the Bi2Se3 hollow nanospheres is about 600 nm and the thickness of the shell is about 40 nm. The shape evolution of Bi2Se3 nanostructures with different volume ratios of EG and OA was also observed: nanoflakes in EG solution, hollow nanospheres as of 2/3, and finally flower-like nanostructures in OA solution. [Copyright &y& Elsevier]

Abstract: Wurtzite GaN taper rods assembled from highly oriented nanoparticles were synthesized using NaNH2 and the as-synthesized GaOOH prismatic rods as reactants at 600°C for 5h. The lengths of the GaN taper rods are in the range of 4–6μm and the diameters are about 0.5–1.5μm. It was found that a slow heating rate (1°Cmin−1) was beneficial to keeping the one-dimensional (1D) skeleton of GaN, otherwise only GaN nanoparticles were obtained with a quick heating rate (10°Cmin−1). Selected area electron diffraction (SAED) patterns and high-resolution transmission electron microscopy (HRTEM) observations revealed that the GaN taper rods assembled from highly oriented nanoparticles and there were crystal defects in the GaN structure. The GaN taper rods displayed luminescence emission in the blue-violet region, which may be related to crystal defects. [Copyright &y& Elsevier]

Abstract: Spinel LiMn2O4 crystal with the grain sizes of about 15 nm is firstly synthesized by hydrothermal route at 180 °C using MnO2 as a precursor. The LiMn2O4 powders synthesized by hydrothermal technique and sol–gel reaction were investigated by X-ray diffraction (XRD) and Transmission electron microscopy (TEM). The LiMn2O4 samples were used as cathode materials for lithium-ion battery, whose electrochemical properties were investigated. The results show that the sample obtained by hydrothermal route has higher capacity than that prepared by sol–gel method. [Copyright &y& Elsevier]

Abstract: Uniform submicron hydrogenated amorphous carbon “test tubes”, both empty and containing nickel particles, were synthesized via the self-catalysis-decomposition of Ni(Hdmg)2 (Hdmg=dimethylglyoxime anion) at 250°C. Since one end of the tubular carbon is always open but the other end is closed, they look like “test tubes”. Transmission electron microscopy images show they have an average inner (outer) diameter of 560nm (740nm) and an average length of around 5.4μm. They were characterized by X-ray diffraction, scanning and transmission electron microscopy, energy-dispersive X-ray analysis, Fourier transform infrared spectroscopy, Raman spectroscopy and thermogravimetric analysis. The results indicated that the “test tubes” consist of amorphous hydrogenated carbon. The magnetic properties of the contained nickel reached a coercivity as high as H c ≈153Oe and showed a remarkable decrease of saturation magnetization. The reaction temperature and solvent are of great importance in determining the final structures. A possible formation mechanism was discussed. [Copyright &y& Elsevier]

Abstract: Coral-like accretion of hollow carbon microspheres with thin walls has been successfully synthesized through a carbon dissolution–precipitation process, where the decomposition of cyclohexane on nickel powder, at 550°C in a sealed system, and is followed by rapid cooling. The final product is tens of microns in size with smooth and uniformly thin shell thickness of approximately 3–4nm. XRD, FESEM, EDX, TEM, HRTEM and Raman spectra were used to characterize the products. The effects of reaction temperature, type of carbon source and cooling process on the formation of the final products have been studied, and a possible formation mechanism for the coral-like product has been proposed. This coral-like accretion of large capacity hollow carbon microspheres has potential applications as a catalyst carrier, in storage or protection of unstable organic materials and microreactors. [Copyright &y& Elsevier]

Abstract: V2O3 and VN nanocrystals have been synthesized by the decomposition of the precursor NH4VO3 and following nitridation in an autoclave with metallic Na flux at 450–600°C. X-ray powder diffraction (XRD) recorded the evolution process of the reaction from precursor NH4VO3 to hexagonal V2O3 and then to NaCl-type VN. In addition, the products were characterized by X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). [Copyright &y& Elsevier]

Abstract: Stable (α) MnS was synthesized by solvothermal method in different solutions at relatively low temperature (120°C for 12h). The effect of the solvents, surfactant, the ratio of reactant to the surfactant and reaction temperature, time on the morphology and phase of products has been investigated. The morphology of the products was mainly affected by the solvent and the concentration of the surfactant. The as-prepared α-MnS crystals have been characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), UV–vis absorption and the PL spectrum and X-ray photoelectron spectroscopy (XPS). The proposed formation mechanism of α-MnS is also discussed. [Copyright &y& Elsevier]

Abstract: Single-crystalline nanorods of β-MnO2, α-Mn2O3 and Mn3O4 were successfully synthesized via the heat-treatment of γ-MnOOH nanorods, which were prepared through a hydrothermal method in advance. The calcination process of γ-MnOOH nanorods was studied with the help of Thermogravimetric analysis and X-ray powder diffraction. When the calcinations were conducted in air from 250 to 1050°C, the precursor γ-MnOOH was first changed to β-MnO2, then to α-Mn2O3 and finally to Mn3O4. When calcined in N2 atmosphere, γ-MnOOH was directly converted into Mn3O4 at as low as 500°C. Transmission electron microscopy (TEM) and high-resolution TEM were also used to characterize the products. The obtained manganese oxides maintain the one-dimensional morphology similar to the precursor γ-MnOOH nanorods. Further experiments show that the as-prepared manganese oxide nanorods have catalytic effect on the oxidation and decomposition of the methylene blue (MB) dye with H2O2. [Copyright &y& Elsevier]

Abstract: Nanocrystalline vanadium nitride (VN) was prepared by a direct thermal liquid–solid reaction between vanadium chloride (VCl4) and sodium azide (NaN3) at 600 °C. Characterized by XRD, TEM, XPS and PL, the composition and morphology of the product were confirmed. The possible reaction mechanism was also discussed. [Copyright &y& Elsevier]

Abstract: In this Letter, we report the facile synthesis of novel porous and hollow microspheres of cubic Mn2O3 nanocrystals of 50–100nm via the heat-treatment of MnCO3 microspheres, which were prepared simply by reacting the MnCl2 ·2H2O with Na2CO3 in aqueous solution at ambient temperature and pressure. The products were characterized by X-ray powder diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy (TEM) and field-emission scanning electron microscopy. Through TEM observation, the growth mechanism of the MnCO3 microspheres was revealed and the possible formation mechanism of the porous and hollow structure of the nanocrystalline Mn2O3 microspheres was also proposed. [Copyright &y& Elsevier]

Abstract: Nanocrystalline Mo2C powders were successfully synthesized at 500°C by reacting molybdenum chloride (MoCl5) with C (graphite or carbon nanotube) in metallic sodium medium. X-ray powder diffractometer (XRD), transmission electron microscope (TEM), X-ray photoelectron spectroscope (XPS) and surface area analyzer (BET method) were used to characterize the samples. Experiments reveal that the carbon source used for the carbide synthesis has a great effect on the particle size and the surface area of the samples. When micro-sized graphite was used as C source the obtained nanocrystalline Mo2C powder consists of particles of 30∼100nm, with a surface area of 2.311m2/g. When carbon nanotubes were used as C source, the as-synthesized Mo2C sample is composed of particles of 20∼50nm, with a surface area of 23.458m2/g, which is an order of magnitude larger than that of the carbide prepared from the graphite. [Copyright &y& Elsevier]

N11As8 crystallites 23-nm thick and 250–700-nm wide in lateral dimension were prepared in alkaline hydrothermal condition. Transmission electron microscope (TEM) images and selected area electron diffraction (SAED) analyses showed that the as-prepared N11As8 was single-crystalline nanosheets of [331] orientation. The N11As8 exhibited an optical absorption onset of 3.00 eV in the visible spectral regime. Its magnetic measurement indicated a weak magnetic hysteresis and unsaturation magnetization with a magnetic susceptibility of 1.37 × 10-4 cm3/g (at 15 kOe) at room temperature, the origin of which was discussed and assigned to the effect of surface species containing Ni ions. The extended Heckel tight-binding calculation revealed that bulk N11As8 has a 3d-localized narrow band below Fermi level and complicated band structure with small band gap in the first Brillouin zone, which supply clues to explain the observed optical and magnetic properties. The formation mechanism of N11As8 was studied and attributed to an alkaline hydrothermal redox route on the basis of the Marsh reaction. [ABSTRACT FROM AUTHOR]

Abstract: Single-crystal MnOOH microrods were prepared hydrothermally by reducing KMnO4 with NH4Cl at 150°C for 24h. After the subsequent heat treatment of the as-prepared MnOOH microrods at 350°C for 10h in air, single-crystal beta-MnO2 microrods were obtained, which retained the similar morphologies of MnOOH microrods. The products were characterized by powder X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The influences of different reductants, the molar ratio between reaction materials, and temperature on the morphology and phase of the final products under hydrothermal conditions are discussed. The reaction temperature and reductant NH4Cl were crucial factors for the formation and morphologies of MnOOH microrods. Based on the experimental results and MnOOH crystal structure, a possible formation mechanism has been proposed on the growth of MnOOH microrods. [Copyright &y& Elsevier]

Abstract: A low-temperature solution-phase method has been demonstrated for the synthesis of uniform nanorods of Bi2S3 with diameter of 18nm and length of below 200nm. Transmission electron microscopy (TEM), selected-area electron diffraction (SAED), and X-ray diffraction (XRD) studies revealed that these nanorods were grown from a colloidal dispersion of amorphous Bi2S3 particles, which was first formed through a thermal reaction between Bi-thiol complexes Bi(SC12)3 and thioacetamide (TAA) in a pure dodecanethiol (C12SH) solvent at a temperature of 95°C. Based on these studies, the growth mechanism of Bi2S3 nanorods was properly proposed. [Copyright &y& Elsevier]

Abstract: PbS nanorod bundles have been synthesized via a surfactant-assisted biphasic interface reaction route at 160oC for 20h. The as-prepared nanorods have diameter of 30nm and length of 0.8μm. Based on the observation of transmission electron microscopy (TEM) images, it is found that the amount of sodium dodecyl sulfonate (SDS) plays a crucial role on the morphology of the products. The formation of one-dimensional (1D) PbS nanostructures could be ascribed to the confined growth between surfactant chains. A possible mechanism is also discussed. [Copyright &y& Elsevier]

Submicron Se and Te rod-like crystals were successfully synthesized via a rapid polyol process by refluxing Na2EO3 (ESe, Te) and (NH3)2S2O3 in ethylene glycol at 180°C for 0.5h under vigorous stirring. The obtained samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), and XPS procedures. Studies found that reaction time and temperature have great influences on the morphology of the final products. [Copyright &y& Elsevier]

Nanocrystalline silicon carbide has been prepared via reacting magnesium silicide (Mg2Si) with carbon tetrachloride (CCl4) in an autoclave at 450–600°C. X-ray diffraction patterns of the products can be indexed as the cubic cell of SiC with the lattice constant, a=4.352 Å, in good agreement with a=4.349 Å (JCPDS card No. 75-0254). The transmission electron microscopy images show that the sample mainly consists of nanoparticles with an average size from 30 to 80 nm co-existing with a small fraction of nanorods and nanowires. Typically the nanorods range from 20 to 40 nm in diameter and the nanowires have diameters of 20 nm and lengths up to 10 μm. The Raman spectrum shows a characteristic sharp peak at 790 cm-1. X-ray photoelectron spectra (XPS) gives an atomic ratio of Si to C as 1.08:1.00 from the quantification of the peak intensities. Photoluminescence spectrum reveals that the SiC sample emits ultraviolet light of 328 nm. A possible mechanism and the influence of temperature on the formation of crystalline SiC are proposed. [Copyright &y& Elsevier]

Vanadium nitride was synthesized by the reaction of VCl4 and NaNH2 at room temperature. X-ray powder diffraction could be indexed as cubic VN with the lattice constant of a=4.134Å. Transmission electron microscopy image showed particle and hollow sphere morphology. The optical properties of the as-prepared VN were investigated. [Copyright &y& Elsevier]