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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]

Single-crystalline metastable In2O3 nanocrystals with size in the range of 5–30 nm were, for the first time, synthesized by a precursor-dehydration route at 490°C under ambient pressure. The precursor was prepared by a hydrolysis solvothermal reaction using InCl3·4H2O as starting materials and ethylenediamine as solvent in the range of 180–230°C. It was found that the precursor had significant effect on the phase composition and phase structure of In2O3. Optical properties of the metastable In2O3 nanocrystals were investigated. [Copyright &y& Elsevier]

Abstract: General and simple methods for the syntheses of borides, carbides and nitrides are highly desirable, since those materials have unique physical properties and promising applications. Here, a series of boride (TiB2, ZrB2, NbB2, CeB6, PrB6, SmB6, EuB6, LaB6), carbide (SiC, TiC, NbC, WC) and nitride (TiN, BN, AlN, MgSiN2, VN) micro/nanocrystals were prepared from related oxides and amorphous boron/active carbon/NaN3 with the assistance of metallic Na and elemental S. In-situ temperature monitoring showed that the reaction temperature could increase quickly to ∼850°C, once the autoclave was heated to 100°C. Such a rapid temperature increase was attributed to the intense exothermic reaction between Na and S, which assisted the formation of borides, carbides and nitrides. The as-obtained products were characterized by XRD, SEM, TEM, and HRTEM techniques. Results in this report will greatly benefit the future extension of this approach to other compounds. [Copyright &y& Elsevier]

Abstract: Through controlling the amount of NaOH added, BiOBr and Bi2O3 with different shapes were hydrothermally synthesized in the reaction system of Bi(NO3)3-hexadecyl trimethyl ammonium bromide (CTAB)-NaOH. As 8mmol of NaOH was added, BiOBr microflowers constructed of nanoflakes were synthesized. The thickness of these single-crystal nanoflakes was about 20nm. In the similar condition, when the amount of NaOH added was 28mmol, Bi2O3 shuttles with concave surfaces were obtained. The length of these shuttles was 100μm and the diameter at the middle of these shuttles was 50μm. The photocatalytic activity of as-prepared BiOBr microflowers was evaluated by the degradation of methyl orange (MO) under visible-light irradiation (λ>420nm), which was up to 96% within 90min. [Copyright &y& Elsevier]

Abstract: Uniform shuttle-like Ln 3+ (Eu3+, Tb3+) doped NaLa(WO4)2 nanocrystals have been solvothermally synthesized, and the size of the nanocrystals could be easily controlled by adjusting the volume ratio of ethylene glycol (EG) to water. Doped with 5mol% Eu3+ and Tb3+ ions, the NaLa(WO4)2 nanocrystals showed strong red and green emissions with lifetimes of 0.8 and 1.40ms, respectively. A high quenching concentration of 15mol% was observed in Eu3+-doped NaLa(WO4)2 nanocrystals and 35mol% in Tb3+-doped NaLa(WO4)2 nanocrystals. The emission intensity measurements of Eu3+-doped NaLa(WO4)2 with different sizes indicated that the emission intensity of shuttles with length of 300nm in average was stronger than that of shuttles with length of 900nm in average, but was weaker than that of needles with length of 4 and 9μm in average. [Copyright &y& Elsevier]

Abstract: NiS nanobelts of hexagonal phase have been hydrothermally synthesized starting from Ni(CH3COO)2·4H2O and Na2S2O3·5H2O at 200°C for 12h. The as-prepared nanobelts were 50nm thick, 70–200nm wide and more than 10μm long. As ethylenediaminetetraacetic acid (EDTA) added, in similar condition, 2μm NiS2 microspheres of cubic phase were prepared. However, as Ni2+/ ratio was 1:1 and the temperature was decreased to 160°C, 5μm NiS2 microspheres constructed of cuboids were formed. [Copyright &y& Elsevier]

Abstract: Rare-earth hexaborides (RB6, R=Ce, Pr, Nd) nanocrystals were prepared by a facile solid state reaction in an autoclave. Single-crystalline RB6 nanocubes were fabricated at 500°C starting from B2O3, RCl3·6H2O and Mg powder. RB6 nanoflakes and nanoparticles could be obtained around 400°C using NaBH4 as boron resource. XRD patterns show that all of the hexaborides are cubic phase with high crystallinity and high purity and have lattice parameters that are consistent with nearly stoichiometric products. Raman spectra elucidate the active vibrational modes of the hexaborides. The TEM and FESEM images clearly show that the nanocubes have an average size of 200nm and nanoparticles of 30nm. Our experiment developed an efficient, simple and low-cost route to prepare RB6, which could be extended further to the preparation of other rare-earth metal hexaborides. [Copyright &y& Elsevier]

Abstract: Hexagonal phase BiPO4 nano-cocoons and monoclinic phase BiPO4 nanorods have been synthesized in the mixed solvents of glycerol and distilled water with the volume ratio of 2:1 at 200°C. The solvothermal evolution process from hexagonal phase BiPO4 nano-cocoons to monoclinic phase BiPO4 nanorods was observed by varying the reaction time from 1 to 3h. In the hydrothermal condition at 160°C, the similar phase transformation from hexagonal phase BiPO4 to monoclinic phase BiPO4 was also observed, accompanying with a morphology transformation from nanorods to octahedron-like microcrystals. It was found that the volume ratio of glycerol to water in the solvothermal condition had a great impact on the shapes of products, while it had no influence on the formation of different phases. The fluorescence spectra of hexagonal phase BiPO4 nano-cocoons and monoclinic phase BiPO4 nanorods were also studied. [Copyright &y& Elsevier]

Abstract: Highly crystalline rhombohedral boron nitride (r-BN) with regular triangular shapes were synthesized on a large scale in a stainless steel autoclave using B2O3 and NaNH2 as reactants at 600°C for 6h. The as-prepared BN triangular nanoplates have an average edge length of 400nm and the thickness of about 60nm. The photoluminescence measurements reveal that the r-BN products show strong yellow-green emission. The as-prepared r-BN has potential optical and optoelectronic applications in high temperature devices due to its excellent thermal stability and anti-oxidation properties. [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: Nanocrystalline lanthanum hexaboride (LaB6) with mean particle size of 30nm has been successfully synthesized at 400°C in an autoclave starting from metallic magnesium powder, NaBH4 and LaCl3. In this case, by using B2O3 instead of NaBH4, LaB6 nanocubes with mean size of ∼200nm were formed at 500°C. The X-ray diffraction (XRD) pattern can be indexed as cubic LaB6 with the lattice constant of a=4.151Å for LaB6 nanoparticles and 4.154Å for LaB6 nanocubes. An atomic ratio of La and B as 1:5.94 was determined from EDS for LaB6 nanoparticles. XPS data of LaB6 nanocubes indicate the atomic ratio of La to B as 1:5.95. Raman spectra indicate the formation of LaB6. [Copyright &y& Elsevier]

Abstract: SnO2 urchin-like structures composed of nanorods with diameters of 10–15nm and lengths of 50–70nm have been hydrothermally synthesized via a H2O2-assisted route without any surfactant, using SnCl2 as raw material. With the addition of methenamine (HMT), SnO2 hollow microspheres with diameters of 2–3μm and shell thickness of 60–140nm were also prepared. The as-obtained products were examined using diverse techniques including X-ray powder diffraction (XRD), Raman spectroscopy, field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), selected-area electron diffraction (SAED), high-resolution TEM and photoluminescence spectra. The gas sensitivity experiments have demonstrated that the as-synthesized SnO2 materials exhibit good sensitivity to alcohol vapors, which may offer potential applications in gas sensors. [Copyright &y& Elsevier]

Abstract: Single-crystalline BaMoO4 microcrystals with uniform shuttle-like morphology have been successfully prepared via a facile aqueous solution mineralization process at room temperature. It was found that the pH value and the reaction temperature had important influences on the formation of the BaMoO4 microcrystals. The shuttle-like microcrystals can be obtained in alkaline aqueous solution (pH=9–14), and when the pH value was adjusted to 6–7, cocoon-like microcrystals appeared. A possible two-stage growth process has been proposed, and the Ostwald ripening was responsible for the formation of the shuttle-like BaMoO4 microcrystals. The products were characterized by XRD, XPS, FESEM, HRTEM and Raman spectroscopy. Room-temperature photoluminescence indicated that the as-prepared BaMoO4 microcrystals had a strong blue emission peak centered at 438nm. [Copyright &y& Elsevier]

Abstract: α-MnO2 nanowires or nanorods have been selectively synthesized via the hydrothermal method in nitric acid condition. The α-MnO2 nanowires hold with average diameter of 50nm and lengths ranging between 10 and 40μm, using MnSO4·H2O as manganese source; meanwhile, α-MnO2 bifurcate nanorods with average diameter of 100nm were obtained by adopting MnCO3 as starting material. The morphology of α-MnO2 bifurcate nanorods is the first one to be reported in this paper. X-ray powder diffraction (XRD), field scanning electron microscopy (FESEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED) and high-resolution transmission electron microscopy (HRTEM) were used to characterize the products. Experimental results indicate that the concentrated nitric acid plays a crucial role in the phase purity and morphologies of the products. The possible formation mechanism of α-MnO2 nanowires and nanorods has been 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 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]

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]

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]

Abstract: The micro-sized Sb2O3 octahedra can be synthesized on a large scale via a simple PEG-1000 polymer-assisted hydrothermal route (PAHR) in the temperature range of 160–180°C for 10–14h. The structures, compositions, and morphologies of the as-synthesized products are derived from X-ray power diffraction pattern, X-ray photoelectron spectra, and field emission scanning electronic microscope. Meanwhile, the optical properties of the micro-sized Sb2O3 octahedra are studied by their photoluminescene spectroscopy and Raman spectrum. Furthermore, the possible growth mechanism of the micro-metered Sb2O3 octahedra is discussed on the basis of a series of supplementary experiments. And it has been found that PEG-1000, sodium tartrate, the reaction temperature, and the reaction time have considerable effects on the final morphology of Sb2O3, while the pH value has an influence on the formation of the Sb2O3 crystals. [Copyright &y& Elsevier]

Millimeter-sized molybdenum nitride (MoN), in the forms of fiber-like prisms or hollow tubes, has been successfully synthesized via thermal ammonolysis of molybdenum polysulfide precursor. The initial morphology of the precursor is well preserved in the final product. This method could be expanded to preparation of other fiber-like nonmetal ceramics without addition of template. The polysulfide precursor (abbreviated to PS), hydrothermally prepared at 30°C (PS1) or 150°C (PS2), was characterized by various methods for better comprehension of the sulfide–nitride topotactic conversion model. [Copyright &y& Elsevier]

Nanocrystalline boron nitride (BN) with needle-like and hollow spherical morphology has been synthesized by nitriding of MgB2 with NH4Cl and NH4Cl–NaN3, respectively. The amount of NaN3 has an obvious effect on the size of the hollow spheres. The samples were characterized by X-ray powder diffraction, Fourier transformation infrared spectroscopy, X-ray photoelectron spectra, and transmission electron microscopy. The possible mechanism of morphology control is also discussed. [Copyright &y& Elsevier]

VOx·nH2O (2.0⩽x⩽2.5) nanoribbons have been synthesized by direct hydrothermal processing of the aqueous solution of NH4VO3 and polyethylene glycol 400 (PEG-400) at pH 3.5–5.5. Techniques of XRD, SEM, TEM, HRTEM, ED, and XPS have been used to characterize the structure, morphology, and composition of the nanoribbons. The VOx·nH2O nanoribbons are up to ∼200 μm in length, 100–150 nm in width, 20–30 nm in thickness, and grow along the [010] direction. The ratios of V4+ to V5+ in the products can be readily controlled by carefully adjusting the periods of reaction time. PEG carries the roles of both transport and reducing agent. A coordination self-assembly mechanism was proposed to elucidate the formation of the VOx·nH2O nanoribbons. [Copyright &y& Elsevier]

Different one-dimensional nickel sulfides, NiS nanorods and Ni9S8 nanorods were synthesized in the presence (Route 1) and absence (Route 2) of gas CO2. X-ray powder diffraction patterns, scanning electron microscopy and transmission electron microscopy images show that the product from Route 1 is NiS nanorods with a diameter of about 50–120 nm, while the product from Route 2 is Ni9S8 nanords about 70–200 nm in diameter. A molecular-template-like mechanism was proposed for the one-dimensional structures growth. The products were also investigated by Raman and photoluminescence (PL) spectroscopy. [Copyright &y& Elsevier]

In this report, a simple and easy polyol route for synthesizing many binary metal sulfides nanocrystallines is demonstrated. Powder X-ray electron diffraction and energy-dispersive X-ray spectrum are applied to investigate the crystallinity and composition of the nanoscale materials. The resulting particle size and morphology are examined by transmission electron microscopy, and the possible mechanism is also briefly discussed. [Copyright &y& Elsevier]

Crystalline β-Ag2Se with treelike, plumelike, pebblelike, rodlike, tubular, polyhedral, and spherical morphologies have been prepared by the solvothermal reaction of silver carbonate and selenium at low temperature (190°C) and characterized by elemental analysis, X-ray diffraction pattern, and scanning electron microscopy. The morphologies and sizes of the products are affected not only by the kind of solvents but also by the reactant concentrations and reaction time and can be conveniently obtained under controlled conditions. The influences of the solvents, the reactant concentrations and reaction time on the shapes and sizes of crystalline Ag2Se are discussed. [Copyright &y& Elsevier]

Copper and silver nanocrystalline chalcogenides, Cu2−xSe, Cu2Te, Ag2Se, and Ag2Te, have been successfully synthesized in a mixture of ethylenediamine and hydrazine hydrate as a solvent at room temperature. Products showed different morphologies, such as nanotubes, nanorods, and nanoparticles. The results indicated that the coordination and chelation abilities of ethylenediamine play an important role in the formation of one-dimensional nanocrystalline binary chalcogenides, and hydrazine hydrate is crucial to the electron transfer in the room temperature reactions. These transition-metal nanocrystalline chalcogenides as prepared were analyzed by X-ray powder diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. The UV-Vis absorption properties of these nanocrystals were also measured. [Copyright &y& Elsevier]

A novel in situ oxidization–sulfidation growth route via a self-purification process has been developed to synthesize β-In2S3 dendrites. To our best knowledge, this is the first example to prepare dendrites of III–VI compounds, which are expected to show particular physical properties. The X-ray analysis (EDXA), X-ray photoelectron spectra (XPS), Raman spectrum and optical properties of β-In2S3 dendrites have also been investigated. It is found that the product is pure In2S3 and shows the strong quantum confinement of the excitonic transition expected for the In2S3 dendrites. [Copyright &y& Elsevier]

Hexagonal phase SnS2 nanoflakes have been synthesized by reactions between an organotin precursor tetrabutyltin [TBT, (CH2CH2CH2CH3)4Sn] and carbon disulfide in hexanes at 180–200°C for 10-40 h. The structure, morphologies, composition, and properties have been characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS), ICP-AES, and Raman and Mo¨ssbauer spectroscopies. XRD patterns determined the hexagonal SnS2 with lattice parameters a=3.6384 A˚, c=5.9201 A˚ obtained in n-hexane, and a=3.6389 A˚, c=5.9288 A˚ in cyclohexane. The flakelike morphologies were mainly caused by the anisotropic growth of SnS2. A possible mechanism is given in the paper. [ABSTRACT FROM AUTHOR]