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Monodispersed PbSe nanocubes were synthesized through a simple hydrothermal method by using Pb2+‐EDTA complex and Na2SeSO3. Composition and morphology of the samples were characterized by means of XRD, TEM and SEM. The gradually releasing of Pb2+ from Pb2+‐EDTA complex, and the adopting of PVP can adjust the growth rate in <100> and <111> directions of PbSe. Both Pb2+‐EDTA complex and PVP played important roles in the crystal growth of the monodispersed PbSe nanocubes. In addition, UV‐vis and photoluminescence properties were characterized. Eg of the PbSe nanocubes is 1.5 eV approximately, which is much larger than that of bulk PbSe. Under PL excitation at 406 nm, a red emission peak at 696 nm is observed, showing that the synthesized PbSe is luminescent nanomaterials. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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In the current paper we designed a simple glucose reduction route for synthesis of sheet‐like Cu dendrites on a high yield, using CuSO4 as the starting material. The reaction was carried out at 180 °C for 18 h in the absence of any structure‐directing agent. The product was characterized by X‐ray powder diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and electron diffraction (ED). Some factors influencing the shapes of Cu microcrystals, including the reaction temperature, time, and the concentration of the starting CuSO4, were investigated. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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Uniform capsule‐like α‐Fe2O3 particles were synthesized via a simple hydrothermal method, employing FeCl3 and CH3COONa as the precursors and sodium dodecyl sulfate (SDS) as soft template. X‐ray powder diffraction (XRD), field emission scanning electron microscopy (FE‐SEM), transmission electron microscopy (TEM), and high‐resolution transmission electron microscopy were used to characterize the structure of synthesized products. Some factors influencing the formation of capsule‐like α‐Fe2O3 particles were systematically investigated, including different kinds of surfactants, the concentration of SDS, and reaction times. The investigation on the evolution formation reveals that SDS was critical to control the morphology of final products, and a possible five‐step growth mechanism was presented by tracking the structures of the products at different reaction stages. 相似文献
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PbS microcrystals with a magic‐square‐shaped structure were successfully fabricated via a simple hydrothermal route, employing (CH3COO)2Pb and Na2S2O3 as the lead and sulfur source without the assistance of any surfactant or template. S2O32‐ ions acted not only a supplier of S2‐ ions but also a coordinating reagent. The formation of the above morphology was the direct result of the coordination between thiosulfate ions and lead ions. Researches indicated that the different synthetic approach could influence the morphology of the final product. A possible formation mechanism was suggested. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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Monodispersed and single‐crystalline hematite (α‐Fe2O3) cubes have been successfully prepared by a template‐free hydrothermal synthetic route with FeCl3 and CH3COONH4. The influences of the reactant concentration, reaction temperature, and reaction time on the crystal growth were systematically investigated. The results show that the monodisperse hematite cubes with high crystalline and narrow size distribution could be fabricated at the hydrothermal temperature of 160 °C for 24 h while the concentrations of FeCl3 and CH3COONH4 were in the range of 0.03‐0.5 M and 0.05‐0.1 M, respectively. In addition, the formation mechanism of hematite cube is also proposed, where the CH3COONH4 plays a role of shape controller in the formation of cube hematite structure. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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Guang‐Ru Tian Si‐Xiu Sun Xin‐Yu Song Wei Zhao Ting You 《Crystal Research and Technology》2008,43(8):817-822
Single‐crystalline dilead pentaoxochromate (Pb2CrO5) with nanorod‐shape has been synthesized by adjusting the pH value of the catanionic reverse micelles formed by a cationic surfactant CTAB (hexadecyltrimethylammonium bromide) and an anionic surfactant SDS (sodium dodecyl sulfonate), followed by a hydrothermal process. The results show that reaction parameters play important roles in the formation of the single‐crystalline Pb2CrO5. The reaction parameters include the kinds of the surfactants, the molar ratio (r) between the mixed cationic and anionic surfactants, reaction time and temperature. The as‐synthesized products are characterized by transmission electron microscopy (TEM), high‐resolution transmission electron microscopy (HRTEM) and powder X‐ray diffraction (XRD). (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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Large‐scale high‐quality BaMoO4 nanocrystals have been synthesized in aqueous solutions under mild conditions with citrate as a simple additive. The crystals have bone‐like, spindle‐like and wheatear‐like morphologies assembled from nanoparticles, nanofibers and have been characterized by X‐ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) techniques. The results showed that experimental parameters had great influences on the shape evolution of products. The adjustment of these parameters such as room temperature stirring time, reaction temperature and reaction time of hydrothermal reaction, can lead to obvious morphology changes of products, and the growth mechanism has been proposed. Room‐temperature photoluminescence indicated that the as‐prepared BaMoO4 nanocrystals had a strong blue emission peak at 481.5 nm. This facile route could be employed to synthesize more promising nanomaterials with interesting self‐assembly structures. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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A new method has been developed for the synthesis of mixed‐valence ammonium vanadate crystals. Single crystals of (NH4)2V3O8 were synthesized on a large scale by hydrothermal reduction of NH4VO3 in ethanol‐H2O solutions in the presence of triblock copolymer Pluronic P123. The crystals are shining thin plates with (001) cleavage planes. Calcination of the (NH4)2V3O8 crystals at 300°C or above resulted in pure phases of V2O5. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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T. Hayashi M. Kinpara J. F. Wang K. Mimura M. Isshiki 《Crystal Research and Technology》2008,43(1):9-13
In order to prepare high purity lead iodide (PbI2) single crystals, the starting material‐iodine (I) has been purified by the sublimation method, and the PbI2 polycrystalline by the normal freezing method. The purification effect of these methods has been confirmed by evaluating the impurity concentration in ingot by glow discharge mass spectrometry (GDMS) analysis. By comparing the purity of three different starting materials, non‐purified iodine+6N‐Pb, purified iodine+6N‐Pb and commercial 6N‐PbI2, PbI2 synthesized by purified iodine in the present experiment has the highest purity. This indicates that these purification methods are suitable. The present research results are expected to prepare high‐resistivity PbI2 used in radiation detector. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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采用温差水热法,以分析纯的Al(OH)3和BeO以及无色纯净的石英为原材料,球形和//s(1121)的片状无色绿柱石为籽晶,在复杂的盐酸混合溶液中生长了无色透明的绿柱石晶体.利用双圈反射测角仪、电子探针、X射线衍射仪和红外光谱仪等仪器,对合成绿柱石晶体的形态、成分及晶体结构进行了详细的研究.结果表明,合成的绿柱石晶体为六方短柱状,主要发育平行双面c{0001}、六方柱m{1010}、a{1120}和六方双锥p{1011}四种单形.合成的绿柱石晶体的成分中(Na2O+ K2O)的质量分数约为0.59;,且c0/a0值为0.9988,可归属于\"正常\"绿柱石向\"四面体\"绿柱石的过渡范畴.在中性或弱碱性环境体系中,通过调整绿柱石中各成分的百分含量,有望在更低的温度、压力条件下合成出高质量的板柱状绿柱石晶体. 相似文献
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Hai Wu Youjin Zhang Maozhong Zhou Chengpeng Yao Xianjin Ge 《Crystal Research and Technology》2016,51(9):508-512
Large single crystals of lanthanide hydroxides [Ln(OH)3 (Ln = La, Pr, Nd, Sm, Eu and Tb)] up to several millimeters have been grown by using solid KOH assisted hydrothermal method. Eu(OH)3 samples, as a representative of the Ln(OH)3 crystals, were characterized by X‐ray diffraction (XRD), 4‐circle single‐crystal diffraction, Fourier transform infrared (FTIR) spectroscopy and X‐ray photoelectron spectroscopy (XPS). FESEM image shows hexagonal prism morphology for the Eu(OH)3 large crystals. Research on the photoluminescence and magnetic properties of Eu(OH)3 species was conducted. 相似文献
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Hiba Kabbara Jaafar Ghanbaja Abdelkrim Redjaïmia Thierry Belmonte 《Journal of Applied Crystallography》2019,52(2):304-311
Nanosecond‐pulsed spark discharge between two lead electrodes in liquid nitrogen has been used to synthesize hexagonal lead nanosheets. These original nanostructures are collected on a substrate located under the electrodes. After the full evaporation of the liquid nitrogen, the nanosheets are oxidized in air and transform into a lead dioxide. The resulting hexagonal sheets have typical widths of around 1 µm and typical thicknesses of around 10 nm. Investigations by energy dispersive spectroscopy microanalysis, transmission electron microscopy, high‐angle annular dark‐field scanning transmission electron microscopy and electron microdiffraction were performed in order to identify the crystal structure in which these hexagonal nanosheets crystallize. An analysis of the chemical composition pointed to a stoichiometric lead dioxide, PbO2. This PbO2 lead dioxide crystallizes in the hexagonal system (a = 0.912 nm and c = 1.265 nm) and belongs to the space group P6/m2/m2/m. On the basis of group theory (symmetry analysis), the nanosheets develop a hexagonal‐prismatic shape in liquid nitrogen, assumed to be an isotropic medium. From the energetic point of view, this shape, dictated by the 6/m2/m2/m point group, corresponds to an absolute extremum, an indicator of the stability of this lead dioxide. A mechanism similar to that of the ledge mechanism explaining the formation of thin plates in a metallic matrix has been adapted and proposed for the formation of the lead nanosheets in the liquid nitrogen. When the liquid nitrogen is removed, the lead nanosheet is oxidized, leading to a lead dioxide, inheriting the nanosheet morphology. As far as the authors are aware, this is the first time that such a lead dioxide has been synthesized by spark discharge in liquid nitrogen followed by oxidation in air. The crystallographic structure is determined and the morphology is explained. A mechanism for the development of the lead nanosheets and their oxidation is proposed. This hexagonal phase, designated γ‐PbO2, is thought to be the third polymorph after the α‐PbO2 and β‐PbO2 phases of lead dioxide, the former being orthorhombic and the latter being tetragonal. 相似文献
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Ultralong α‐Ni(OH)2 nanobelts with uniform size have been prepared on large scale via a facile template‐free hydrothermal method. The as‐prepared nanobelts were single crystals, with several tens of microns in length and about 100 nm in width. For the whole process, a novel nucleation–aggregation–dissolution–seed‐directed growth mechanism was proposed based on the experimental results. The roles of aqueous ammonia and hydrothermal temperature were also discussed. Furthermore, porous NiO nanobelts were obtained by annealing the as‐prepared Ni(OH)2 nanobelts. This facile, template‐free, and low cost method might feasibly be scaled up for industrial production. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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Gallium orthophosphate (GaPO4) single crystals were grown by the reverse temperature gradient method from phosphoric acid solutions under hydrothermal conditions. Twins after (110) were studied by etching faces having been cut perpendicular to one of the twofold axes. Based on the determination of the twin boundary position as well as on the knowledge of the growth rates of different crystallographic forms, a few faces have been chosen to be quite promising for growing high‐quality GaPO4 single crystals if they are offered at the referring seed crystal. From the characterization of the grown crystals conditions have been found, which may lead to the reduction of the inversion twin number during the growth process. 相似文献
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Jinmiao Zhu Chengli Yao Xinsong Yuan Chen Chen Chunxia Qi Yuehua Xia Lin Dong 《Crystal Research and Technology》2010,45(8):840-844
The morphology of gold nanoparticles was controlled with hydrogentetrachloroaurate (HAuCl4) and xylitol through a hydrothermal process using xylitol as reducing agent and controlled reagent. The molar ratio of xylitol relative to HAuCl4, reaction time and temperature played important roles in determining the geometric shape and size of the product. These nanoplates were single crystals with planar width of 80‐500 nm. The formation of nanobelts and two‐dimensional single‐crystal nanosheets is explained by the preferential adsorption of xylitol molecules from the solution onto the {111} planes of Au nuclei. These nanosheets could be used, for example, in gas sensors, in the fabrication of nanodevices and substrate materials, in property studies, and also for inducing hypothermia in tumors. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献