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Graphene‐wrapped metal oxide nanocrystals, such as Fe2O3, Co3O4, and SnO2, with well‐controlled size, shape, and density, are fabricated through a mechanism analogous to the colloidal coagulation effect at room temperature. A simple extension of this method yields Fe2O3/graphene composite, which is used for Li storage. [ABSTRACT FROM AUTHOR]

Abstract: Co2P nanocrystals were successfully synthesized by a polymer-assisted hydrothermal method. The reaction was carried out at 190 °C–220 °C using cobalt chloride hexahydrate (CoCl2·6H2O) as Co-source and yellow phosphorous as P-source. Polyacrylamide (PAM) was used as surfactant. By controlling the experiment parameters such as the reaction temperature and the amount of polyacrylamide (PAM), Co2P nanocrystals with the rod-like or flower-like morphology could be prepared successfully. The phase and the morphology of the samples were characterized by X-ray diffraction (XRD), transmission electron microscopes (TEM), electron diffraction pattern (ED) and high resolution transmission electron microscope (HRTEM). Furthermore, based on the results of the TEM observation, the possible formation processes of the Co2P nanorods or nanoflowers were also discussed. [Copyright &y& Elsevier]

Nanocrystalline titanium diboride (TiB2) has been prepared by the reaction of TiCl4 with NaBH4 in the temperature range of 500–700 °C in an autoclave. X-ray powder diffraction (XRD) patterns can be indexed as hexagonal TiB2 with the lattice constants of a=3.032 and c=3.229 A˚. Transmission electron microscopy (TEM) image shows particle morphology, with average size of 15 nm for the powder obtained at 600 °C. Selected area electron diffraction (SAED) pattern confirms the prepared hexagonal TiB2. The oxidation behavior of TiB2 is studied by thermogravimetric analysis (TGA) and differential thermal analysis (DTA). [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]

Highlights: [•] Pure cubic and tetragonal CuFe2O4 nanocrystals. [•] C- and t-CuFe2O4 exhibit similar electrode reactions except the first cycle. [•] C-CuFe2O4 shows superior capacity and rate capability. [•] Fe x Cu1−x alloy in the discharged electrode were observed for the first time. [ABSTRACT FROM AUTHOR]

Abstract: Starting from waste polytetrafluoroethylene (PTFE), metal oxides (TiO2, V2O5, Nb2O5, and MoO3) and metal sodium, several nanocrystalline transition metal carbides (TiC, VC, NbC, and Mo2C) have been prepared through a thermal reduction route in an autoclave at 600 °C. It is found that the obtained NbC nanocrystallines have a superconducting transition temperature at 11.6 K. [Copyright &y& Elsevier]

Abstract: MnCO3 microstructures, including 2.3μm microplates with the thickness of 200nm and 3.1μm microspheres stacked with 50nm-thick sheets, were hydrothermally prepared in the assistance of sodium dodecyl benzene sulphonate (SDBS) and dodecyl sulfonic acid sodium (SDS), respectively. With the as-synthesized MnCO3 as precursors followed by annealing at 400°C for 4h, mesoporous γ-MnO2 microplates and microspheres with the pore size of 4–50nm, which basically preserved the initial shapes, were obtained. The Brunauer–Emmett–Teller surface areas of the as-prepared γ-MnO2 microplates and microspheres were 52.1m2 g−1 and 50.2m2 g−1, respectively. The electrochemical property tests over Li+ batteries showed that the initial discharge capacity of γ-MnO2 microplates and microspheres were 1997mAhg−1 and 1533mAhg−1. Noticeably, even after 100cycles, the discharge capacity of γ-MnO2 microplates was still as high as 626mAhg−1, indicating the decent cycle behavior. In addition, mesoporous γ-MnO2 was also applied as adsorbents in water treatment, and γ-MnO2 microplates and microspheres could remove about 55% and 80% of Congo red. [Copyright &y& Elsevier]

Abstract: Zinc blende (ZB) CdSe hollow nanospheres were solvothermally synthesized from the reaction of Cd(NO3)2·4H2O with a homogeneously secondary Se source, which was first prepared by dissolving Se powder in the mixture of ethanol and oleic acid at 205°C. As Se power directly reacted with Cd(NO3)2·4H2O in the above mixed solvents, wurtzite (W) CdSe solid nanoparticles were produced. Time-dependent experiments suggested that the formation of CdSe hollow nanospheres was attributed to an inside-out Ostwald ripening process. The influences of reaction time, temperature and ethanol/oleic acid volume ratio on the morphology, phase and size of the hollow nanospheres were also studied. Infrared (IR) spectroscopy investigations revealed that oleic acid with long alkene chains behaved as a reducing agent to reduce Se powder to Se2− in the synthesis. Photoluminescence (PL) measurements showed that the ZB CdSe hollow nanospheres presented an obvious blue-shifted emission by 42nm, and the W CdSe solid nanoparticles exhibited a band gap emission of bulk counterpart. [Copyright &y& Elsevier]

Abstract: CdSe micro/nanocrystals with multiform morphologies, including multi-foots rods, flower-like structures and hollow spheres, have been successfully synthesized by a facile solvothermal method in ethylene glycol (EG). These morphologies could be achieved simply by varying the cadmium source. In addition, different crystal phases of the as-obtained CdSe micro/nanocrystals have also been successfully controlled. Furthermore, the possible growth mechanism for different morphologies and crystal phases of CdSe micro/nanocrystals were also discussed. [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: Hexagonal BN (h-BN) particles were prepared by using BBr3, NH4Br and metallic Na as reactants in stainless steel autoclaves at 450ºC for 24h; When the target temperature was set in the range of 500–600ºC, cubic BN (c-BN) particles that co-existed with h-BN were obtained. It is found that 600ºC and a molar ratio of BBr3 to NH4Br of 1:3 are the optimal reaction parameters for the highest yield production of c-BN particles. c-BN powder with controllable content has been synthesized through a one-step method in the absence of solvents. The as-obtained samples that contain pure h-BN and the mixture of c-BN and h-BN have high thermal stabilities in ambient atmosphere below 920 and 1100ºC, respectively. [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: 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: A sort of novel leaf-shaped SnS2 nanocrystals have been synthesized by controlled reaction of CH3CH2OCS2K with SnCl4·5H2O in aqueous solution in the absence of surfactant. The leaf-shaped nanocrystals consist of very thin sheets with several microns in length and 100–300nm in width. The structure, composition, and morphology of the as-prepared leaf-shaped SnS2 nanocrystals were characterized by XRD, Raman spectra, XPS, and FE-SEM, respectively. Elemental analysis, FT-IR spectra, and TEM were further used to study the formation mechanism of the leaf-shaped SnS2 nanocrystals. A possible mechanism of producing lamellae – breaking into nanosheets – rolling and assembling was suggested for the leaf-shaped SnS2 nanocrystals formation based on experimental results. [Copyright &y& Elsevier]

Abstract: The phase transition of CdSe nanocrystallines from zinc blende to wurtzite phase can be controlled by varying the volume ratio of ethanolamine (EA) and water (WA) in their mixed solution and the morphologies of the CdSe nanocrystals are controlled simultaneously. The phase transition has been demonstrated by XRD patterns and HRTEM images. The samples are investigated by Raman spectrum. The Raman shifts of the samples show a gradual blue shift with the gradual transformation from zinc blende to wurtzite CdSe phase. This method is convenient and controllable which can provide a strategy way to control the phase and morphology of the nanomaterials and study their phase transitions in nanoscale field. [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: nanocrystal with dendritic morphologies was synthesized via a solvothermal reaction between nickel sulfate (Ni-source) and yellow phosphorous (P-source) in a mixture solution of glycol and water. X-ray powder diffraction (XRD), electron diffraction pattern (ED) and transmission electronic microscopy (TEM) studies show that the as-synthesized nanocrystals is pure with a hexagonal phase and a dendritic morphology. The growth mechanism of dendrites involves a special solid–solution–solid transformation as well as an Ostwald ripening process. Moreover the growth of nanodendrites occurs at the expense of nanospheres. The effects of experimental conditions such as the volume ratio of glycol to water and solvothermal temperature on the final products were also discussed. [Copyright &y& Elsevier]

Abstract: Two kinds of carbon nanotubes (CNTs) with different inner diameter (less than 10nm: CNTs-1 and between 60 and 100nm: CNTs-2) were used as catalyst supports. The platinum particles were simply deposited on the outside surface (CNTs-1) and inside (CNTs-2) and were easily reduced to Pt0 by refluxing. The catalysts exhibit high activities in the selective hydrogenation of cinnamaldehyde which contains both Ce:glyph name="dbnd" />O bonds. But the selectivity of these two catalysts was quite different under same reaction conditions. The high selective hydrogenation of Cs observed over catalyst 3%Pt/CNTs-2, while the completely hydrogenation of both Ce:glyph name="dbnd" />O bonds was found over catalyst 3%Pt/CNTs-1. [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: Zinc-doped SnO2 nanocrystals were prepared by a simple hydrothermal process. X-ray diffraction (XRD) patterns show that as-prepared samples are of tetragonal rutile structure of SnO2. Transmission electron microscopy (TEM) and field emission scanning electron microscopy (FE-SEM) characterizations confirm that the morphologies of zinc-doped SnO2 nanocrystals are “flower”-constructed nanorods. Photoluminescence (PL) measurement of the zinc-doped SnO2 crystals reveals a purple emission band centered at ∼440nm. The influences of the hydrothermal reaction temperature, the molar ratio of Zn2+ and Sn4+ as well as the concentrations of NaOH have been studied. The possible growth mechanisms of flower-like nanocrystals were discussed. [Copyright &y& Elsevier]

Abstract: CuO shuttle-like nanocrystals were synthesized by the hydrolysis of cupric acetate (Cu(CH3COO)2·H2O) via a simple surfactant-assisted hydrothermal route at low temperature. It is found that the copper source, reaction temperature, reaction time, and surfactant cetyltrimethylammonium bromide (CTAB) are of importance to form the shuttle-like aggregates made by nanocrystals. A possible oriented-attachment mechanism for these aggregates is proposed based on their shape evolutions. [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: Antimony dendritic nanocrystals have been prepared in a large scale by the reduction of Sb3+ with metallic zinc powder at room temperature in aqueous or alcoholic solution. It is found that homogeneous Sb3+ solution and rapid reduction reaction play important role in the formation of Sb dendrites. The possible formation mechanism of Sb dendrites is also investigated. [Copyright &y& Elsevier]

Abstract: A complex reaction route was developed for the preparation of flower-like cobalt nanocrystals by using 2-hydroxy-4-(1-methylheptyl) benzophenone oxime (N530), a normally effective chelate extracting agent. X-ray powder diffraction pattern shows that the cobalt nanocrystals coexist of both hexagonal close-packed (hcp) and cubic close-packed (ccp) forms, with flower-like architecture characterized by a field emission scanning electronic microscopy. The magnetic coercivity Hc of the as-prepared cobalt crystals came up to 360Oe at room temperature. The existence of the precursor N530–CoCl2 complex was determined by a Fourier transform infrared (FT-IR) spectrometer. Experiments suggested that the existence and the framework structure of the precursor complex have a considerable effect on the final architectures of cobalt nanocrystals. [Copyright &y& Elsevier]

Abstract: Sb2O3 nanorods were successfully prepared via a mild hydrothermal route based on the reactions between SbCl3 and NH3·H2O in aqueous solution at 120–180°C for 12h. The as-prepared Sb2O3 nanorods were characterized by X-ray diffraction (XRD), transmission electronic microscopy (TEM), and X-ray photoelctron spectroscopy (XPS). Results showed that NH3·H2O played a significant role in the formation of Sb2O3 nanorods. The presence of NH3·H2O could greatly favor the reaction progress toward the right-hand side and led to the orientation growth of Sb2O3 nanorods. A possible mechanism for the formation of Sb2O3 nanocrystallites was discussed. [Copyright &y& Elsevier]

Abstract: Metastable greigite (Fe3S4) nanocrystallites with different morphologies have been selectively fabricated via a simple solution-based route. The influence of reaction temperature on the formation of iron sulfides is studied and it is found that the reaction temperature play key role in the preparation of pure Fe3S4 nanocrystallites. Based on the investigation of the magnetic properties of the products, it reveals that the morphology of the products have important influence on the magnetic properties. [Copyright &y& Elsevier]

Abstract: ZnO nanocrystals with column-, rosette- and fiber-like morphologies have been synthesized by annealing their precursors at 550°C under ambient pressure. The precursors were prepared via a hydrothermal process using different starting materials. The products were characterized using XRD, XPS, DT-TG, SEM and PL techniques. It was found the morphologies of ZnO nanocrystals have significant effect on their luminescent properties in particular the strength of luminescence. Besides the emissions at ca. 390 and 490nm, the rosette- and fiber-like ZnO nanocrystals have an additional emission at ca. 425nm. [Copyright &y& Elsevier]

A new MnOOH precursor route has been developed to synthesize single-crystalline nanorods of tetragonal β-MnO2. Uniform γ-MnOOH nanorods were first prepared by reducing KMnO4 with KI under hydrothermal conditions at 120 °C. After calcination of the γ-MnOOH nanorods at 250 °C for 2 h in air, β-MnO2 nanorods retaining the morphologies of γ-MnOOH nanorods were obtained. The temperature, time and heating speed of calcination were found to be important for the morphologies of the β-MnO2 nanorods. [Copyright &y& Elsevier]

Elegant 3D SnS urchin-like architectures have been successfully prepared using SnCl2·2H2O and KSCN as starting materials in ethylene glycol under a mild solvothermal condition. The morphological transformation from 3D frameworks into 1D nanostructures has been observed, which were strongly dependent on the prolonged reaction time. The prepared products were characterized by various techniques, such as XRD, XPS, FESEM, TEM and ED. The possible formation mechanism was also discussed. [Copyright &y& Elsevier]

Copper sulfide (CuS) nanocrystals with special morphologies, such as flower- and trepang-like morphology have been successfully synthesized via a simple and convenient solution route at low temperature from shuttle-like CuO crystals. The morphology of the products can be easily controlled by choosing appropriate solvent as the reaction medium. Studies found that the copper source and reaction time also have important influence on the morphology of the final products. [Copyright &y& Elsevier]

Sb aligned-nanowire bundles, tube-groove-like nanostructures and dendrites have been prepared via a low-temperature solvothermal metal-reduction route. It is found that solvent, reaction temperature and time play important roles in the morphology control of the final Sb products. The possible orientated aggregation growth mechanism was proposed for the formation of these three kinds of Sb nanocrystals with typical morphologies. [Copyright &y& Elsevier]

Nanocrystalline titanium oxynitride has been synthesized by a thermal liquid–solid metathesis reaction between TiCl4 and NaN3 at 350 °C. XRD shows the product is TiN0.91O0.09 with a NaCl-type structure (a=4.236 A˚). TEM reveals the product is granular nanocrystals with size of 15–35 nm. XPS measurements indicate that the product is titanium oxynitride rather than titanium nitride. The photoluminescence spectra of the as-prepared nanocrystallites show the ultraviolet light emission at about 330–350 nm, which is reported for the first time. [Copyright &y& Elsevier]

Nanocrystalline CdE (E=Se, Te) has been successfully synthesized by employing chalcogenites (Na2SeO3 and K2TeO3) as chalcogen sources via γ-irradiation route in the presence of ammonia at room temperature. In the procedures, SeO32− and TeO32− anions were gradually reduced to release Se2− and Te2− in the irradiation field, and then the reduced Se2− or Te2− was combined with Cd2+ ions to produce CdE. The final products were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). [Copyright &y& Elsevier]

Abstract: Nanocrystalline ZrC has been prepared via a convenient route by the reaction of metallic magnesium powder with zirconium oxide and lithium carbonate in an autoclave at 600°C. X-ray powder diffraction pattern indicated that the product was cubic zirconium carbide, and the cell constant was a =4.693Å. Scanning electron microscopy (SEM) image showed particles with an average size of about 30nm. The product was also studied by thermogravimetric analysis (TGA). It had good oxidation resistance below 250°C in air. [Copyright &y& Elsevier]

Abstract: Urchin-like Fe3BO5@carbon core–shell structures (defined as “FBOC”) have been fabricated by a one-step co-pyrolysis method using boric acid and ferrocene as raw materials. This complex architecture is composed of high-density Fe3BO5@carbon nanocables that stand on Fe3BO5@carbon structure. After removing the Fe3BO5, hollow urchin-like carbon material was obtained. In the reaction process, B2O3 and H2O that decomposed from H3BO3 have synergistic effect on the formation of urchin-like structures. It is found that urchin-like structures can also be obtained when other materials that can release H2O and B2O3 react with ferrocene. The influences of the reaction conditions on the preparation of FBOC have been discussed in detail. [Copyright &y& Elsevier]

Abstract: A simple biomolecule-assisted hydrothermal approach was developed to synthesize one-dimensional copper sulfide self-assembled with nanocrystallites. The strategy presented here is the application of l-cysteine, acting not only as complexing agent but also as sulfur source. [Copyright &y& Elsevier]

Abstract: Nanocrystalline niobium carbide (NbC) was successfully synthesized at 550 °C by using a co-reduction route. X-ray powder diffraction and X-ray photoelectron spectra confirmed the formation of cubic NbC. Transmission electron microscopy image revealed that typical NbC crystallites are composed of uniform particles having an average size of about 30 nm. Thermogravimetric analysis showed that the oxidation of nanocrystalline NbC occurred between 350 and 550 °C. [Copyright &y& Elsevier]

Nanocrystalline titanium diboride (TiB2) powders were successfully synthesized at 650 °C by using TiCl4, Mg and MgB2 as the reactants. Transmission electron microscopy images show that typical TiB2 crystallites are composed of uniform particles with the average grain size of about 40 nm. [Copyright &y& Elsevier]