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Single-crystal MnWO 4 nanowires were successfully prepared for the first time via a simple hydrothermal method without any surfactants. The as-prepared products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and high-resolution transmission electron microscopy (HRTEM). The effect of pH value, precursor, and reaction temperature on the formation of MnWO 4 nanocrystals was investigated. The precursor was found to be vital to the formation of MnWO 4 nanowires. It is rational to expect that one-dimensional nanostructures of other tungstates may also be synthesized by this simple method. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we report the obtention of MnWO4 nanocrystals with different shapes, such as: nanospheres, nanorods, and urchin-like microspheres were synthesized by a surfactant-free hydrothermal method. The as-obtained powders were characterized by X-ray diffraction patterns and transmission electron microscopy. XRD patterns indicate that these crystals have a wolframite-type monoclinic structure without deleterious phases. The TEM images revealed that the pH values and precursors played a key role in the morphology-controlled synthesis of MnWO4 nanocrystals. This green method is an effective approach to the controlled growth of MnWO4 nanocrystals with different shapes, which are of interest for both theoretical investigations and practical applications. Finally, a possible growth mechanism for the formation of the MnWO4 microcrystals with different shapes was discussed in detail. [Copyright &y& Elsevier]

Abstract: In this paper, we report the shape-controlled synthesis of MnWO4 nanocrystals by a simple hydrothermal method without any surfactants and templates. The as-prepared powders were characterized by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). It is found that MnWO4 nanofibers, nanorods, nanoflakes, and nanoparticles can be selectively prepared by tuning the experimental conditions such as the pH values and precursors. This green chemistry method is simple and highly reproducible, which can be extended to the shape-controlled synthesis of other metal oxide nanocrystals. [Copyright &y& Elsevier]

Abstract: PbWO4 dendrites have been successfully synthesized by a simple sonochemical method without any surfactants at room temperature. The as-prepared powders were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), electron diffraction (ED), and high-resolution transmission electron microscopy (HRTEM). The effect of pH value, molar ratio of [WO4 2−]/[Pb2+], reaction time, and the initial concentration of the starting solution on the formation of PbWO4 dendrites was investigated. Experimental results indicate that the molar ratio of [WO4 2−]/[Pb2+] played a crucial role in the formation of PbWO4 dendrites. A growth mechanism of PbWO4 dendrites was also discussed. The present process is proved to be environment-friendly, and can be extended to the controllable synthesis of other tungstates. [Copyright &y& Elsevier]

Abstract: In this paper, we report a simple sonochemical method to synthesize PbWO4 dendrites without any templates. The obtained products were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The effect of the pH value, precursor and reaction time on the formation of PbWO4 dendrites was investigated. It is found that the obtained PbWO4 dendrites were composed of clusters of nanorods. It is rational to expect that dendritic structures of other oxides may also be synthesized by this simple method. [Copyright &y& Elsevier]

Abstract: In this paper, we report a simple hydrothermal method to synthesize barium strontium titanate (Ba1−x Sr x TiO3, x =0–1) dendrites without any templates. The obtained products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), electron diffraction (ED), and energy-dispersive X-ray spectroscopy (EDX), respectively. All the samples were identified as cubic perovskite phase by XRD and the obtained Ba1−x Sr x TiO3 (x =0–1) dendrites were single-crystal. The formation process of Ba1−x Sr x TiO3 dendritic structures was also investigated. It is rational to expect that dendritic structures of other perovskite oxides may also be synthesized by this simple method. [Copyright &y& Elsevier]

Abstract: Well-crystallized single-crystal BiFeO3 (BFO) nanoflakes have been successfully synthesized for the first time by the hydrothermal method assisted by KNO3. The as-prepared samples were characterized by X-ray powder diffraction (XRD), transmission electron microscope (TEM), high-resolution TEM (HRTEM), and physical property measurement system (PPMS). It was found that KNO3 played a key role in the formation of BFO nanoflakes. The as-prepared BFO nanoflakes were single-crystal in structure and showed super paramagnetic behavior at room temperature. It is expected that this process may be extended to the synthesis of other kinds of nanostructure materials, which will be beneficial to their detailed experimental investigation of the size- and morphology-dependent properties. [Copyright &y& Elsevier]

Abstract: In this paper, we report a simple hydrothermal method without any surfactants, for the first time, to synthesize single-crystal BaTiO3 dendrites. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron diffraction (ED), and high-resolution transmission electron microscopy (HRTEM). The KOH concentration was found to be vital to the final formation of BaTiO3 dendrites. An obvious morphology evolution from sphere-like shape to dendrite was observed when KOH concentration was decreased from 1 M to 0.1 M. It is rational to expect that dendritic structures of other perovskite oxides may also be synthesized by this simple method. [Copyright &y& Elsevier]

Abstract: Bi2Fe4O9 (BFO) nanoparticles were successfully synthesized by a hydrothermal method at a temperature as low as 100°C. The as-prepared powders, characterized by X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), transmission electron microscope (TEM) and physical property measurement system (PPMS), exhibited a pure BFO phase about 100nm size with uniform sheet-like shape and exhibited an AF order at room temperature. It was found that high alkali concentration and alkali ion Na+ played a key role in the formation of BFO nanoparticles at a low temperature of 100°C. [Copyright &y& Elsevier]

Abstract: Single-crystal PbTiO3 nanorods have been synthesized by phase transformation from Pb2Ti2O6 nanorods. In the process, single-crystal Pb2Ti2O6 nanorods were first prepared by hydrothermal method, and single-crystal PbTiO3 nanorods were obtained by phase transition from the resultant Pb2Ti2O6 nanorods. Various approaches including XRD, Raman, TEM, SAED, and HRTEM were used to investigate the as-prepared products. It was found that Pb2Ti2O6 nanorods played a key role in the formation of PbTiO3 nanorods. [Copyright &y& Elsevier]