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Sample records for hydrothermal synthesis structural

  1. Hydrothermal organic synthesis experiments

    Science.gov (United States)

    Shock, Everett L.

    1992-01-01

    Ways in which heat is useful in organic synthesis experiments are described, and experiments on the hydrothermal destruction and synthesis of organic compounds are discussed. It is pointed out that, if heat can overcome kinetic barriers to the formation of metastable states from reduced or oxidized starting materials, abiotic synthesis under hydrothermal conditions is a distinct possibility. However, carefully controlled experiments which replicate the descriptive variables of natural hydrothermal systems have not yet been conducted with the aim of testing the hypothesis of hydrothermal organic systems.

  2. Structural archetypes in nickel(II) hybrid vanadates. Towards a directed hydrothermal synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Luis, R. Fernandez de; Urtiaga, M.K. [Dpto. Mineralogia y Petrologia, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco/UPV/EHU, Apdo. 644, 48080 Bilbao (Spain); Mesa, J.L.; Rojo, T. [Dpto. Quimica Inorganica, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco UPV/EHU, Apdo. 644, 48080 Bilbao (Spain); Arriortua, M.I. [Dpto. Mineralogia y Petrologia, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco/UPV/EHU, Apdo. 644, 48080 Bilbao (Spain)], E-mail: maribel.arriortua@ehu.es

    2009-07-01

    In the present work, we relate the modifications of the initial synthesis parameters (pH value, stoichiometry and concentration) with the different structural archetypes obtained in the {l_brace}Ni/Bpy/VO{r_brace} and {l_brace}Ni/Bpe/VO{r_brace} systems (4,4'-bipyridine (Bpy), 1,2-di(4-pyridyl) ethylene (Bpe)). The vanadium coordination is partially controlled by the hydrothermal synthesis conditions, and the final crystal structures depend on the synergetic interaction between the metal-organic subnets and the vanadium oxide subunits.

  3. Hydrothermal Synthesis of Metal Silicates

    Institute of Scientific and Technical Information of China (English)

    Lii Kwang-Hwa

    2004-01-01

    Organically templated metal phosphates have been extensively studied because of interesting structural chemistry and potential applications in catalysis. However, in most cases the organic templates cannot be removed without collapse of the frameworks. This is in contrast to the high thermal stability and extensive applications of zeolites in refinery and petrochemical processes.Therefore, studies have been directed to the synthesis of transition metal silicates to produce more stable frameworks. Our synthetic methods are twofold, namely mild hydrothermal reactions in Teflon-lined autoclaves at 100-200 ℃ using organic amines as templates and high-temperature,high-pressure hydrothermal reactions in gold ampoules contained in a high-pressure reaction vessel at ca. 550 ℃ and 150 Mpa using alkali metal cations as templates. In this presentation I will report the high-temperature, high-pressure hydrothermal synthesis, crystal structures, and solid-state NMR spectroscopy of a number of new silicates of indium, uranium, and transition metals.

  4. Flower-like NiO structures: Controlled hydrothermal synthesis and electrochemical characteristic

    Energy Technology Data Exchange (ETDEWEB)

    Chai, Hui; Chen, Xuan [Key Laboratory of Clean Energy Material and Technology, Ministry of education, Xinjiang University, Urumqi 830046, Xinjiang (China); Key Laboratory of Advanced Functional Materials, Institute of Applied Chemistry, Xinjiang University, Urumqi 830046, Xinjiang (China); Jia, Dianzeng, E-mail: jdz0991@gmail.com [Key Laboratory of Clean Energy Material and Technology, Ministry of education, Xinjiang University, Urumqi 830046, Xinjiang (China); Key Laboratory of Advanced Functional Materials, Institute of Applied Chemistry, Xinjiang University, Urumqi 830046, Xinjiang (China); Bao, Shujuan [Key Laboratory of Clean Energy Material and Technology, Ministry of education, Xinjiang University, Urumqi 830046, Xinjiang (China); Key Laboratory of Advanced Functional Materials, Institute of Applied Chemistry, Xinjiang University, Urumqi 830046, Xinjiang (China); Zhou, Wanyong [Chemistry and Chemical Engineering of Xinjiang University, Xinjiang University, Urumqi 830046, Xinjiang (China)

    2012-12-15

    Graphical abstract: Flower-like porous NiO was obtained via thermal decomposition of the precursor prepared by a hydrothermal process using hexamethylenetetramine and polyethylene glycol as hydrolysis-controlling agent and surfactant, respectively. The morphology and microstructure of as-synthesized NiO were characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results of electrochemical measurements demonstrated that the flower-like porous NiO has high capacity (340 F g{sup −1}) with excellent cycling performance as electrode materials of electrochemical capacitors (ECs), which may be attributed to the unique microstrcture of NiO. Data analyses indicated that NiO with novel porous structure attractive for practical and large-scale applications in electrochemical capacitors. Display Omitted Highlights: ► Synthesis and characterization of NiO with novel porous structure is presented in this work. ► The electrochemical performance of product was examined. ► NiO with excellent performance as electrode materials may be due to the unique microstrcture. ► NiO with novel porous structure attractive for practical with high capacity (340 F g{sup −1}). -- Abstract: Flower-like porous NiO was obtained by thermal decomposition of the precursor prepared by a hydrothermal process with hexamethylenetetramine and polyethylene glycol as hydrolysis-controlling agent and surfactant, respectively. The morphology and microstructure of as-synthesized NiO were characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The resulting structures of NiO exhibited porous like petal building blocks. The electrochemical measurements’ results demonstrated that flower-like porous NiO has high capacity (340 F g{sup −1}) with excellent cycling performance as electrode materials for

  5. Controlled hydrothermal synthesis and structural characterization of a nickel selenide series.

    Science.gov (United States)

    Zhuang, Zhongbin; Peng, Qing; Zhuang, Jing; Wang, Xun; Li, Yadong

    2005-12-16

    A series of nickel selenides (NiSe2 microcrystals, Ni(1-x)Se and Ni3Se2 microspheres) has been successfully synthesized through a convenient, low-temperature hydrothermal method. A good nucleation and growth environment has been created by forming a uniform and transparent solution reaction system. The compositions (including the x value of Ni(1-x)Se), phase structures, as well as the morphologies of nickel selenides, can be controlled by adjusting the Ni/Se ratio of the raw materials, the pH, the reaction temperatures and times, and so forth. The newly produced Se microspheres in the system have been used as both reactant and in situ template to the Ni(1-x)Se microspheres. It is found that Ni(1-x)Se microspheres act as the intermediate precursor during the formation of Ni3Se2 microspheres. Under certain conditions, hexagonal NiSe microspheres can be converted into rhombohedral NiSe nanowires in solution. The formation mechanisms of a series of nickel selenides has been investigated in detail by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses. This work has provided a general, simple, and effective method to control the composition, phase structure, and morphology of metal selenides in aqueous solution, which will be important for inorganic synthesis methodology and further applications of selenides.

  6. A microporous potassium vanadyl phosphate analogue of mahnertite. Hydrothermal synthesis and crystal structure

    Energy Technology Data Exchange (ETDEWEB)

    Yakubovich, Olga V. [M.V. Lomonosov Moscow State Univ. (Russian Federation). Dept. of Crystallography; Russian Academy of Science, Moscow (Russian Federation). Inst. of Geology of Deposits, Petrography, Mineralogy and Geochemistry; Steele, Ian M. [Notre Dame Univ., IN (United States). Notre Dame Integrated Imaging Facility; Kiriukhina, Galina V.; Dimitrova, Olga V. [M.V. Lomonosov Moscow State Univ. (Russian Federation). Dept. of Crystallography

    2015-09-01

    The novel phase K{sub 2.5}Cu{sub 5}Cl(PO{sub 4}){sub 4}(OH){sub 0.5}(VO{sub 2}).H{sub 2}O was prepared by hydrothermal synthesis at 553 K. Its crystal structure was determined using low-temperature (100 K) single-crystal synchrotron diffraction data and refined against F{sup 2} to R = 0.035. The compound crystallizes in the tetragonal space group I4/mmm, with unit-cell parameters a =9.8120(8), c = 19.954(1) Aa, V = 1921.1(2) Aa{sup 3}, and Z = 4. Both symmetrically independent Cu{sup 2+} sites show elongated square-pyramidal coordination. The V{sup 5+} ions reside in strongly distorted five-vertex VO{sub 5} polyhedra with 50% occupancy. The structure is based on a 3D anionic framework built from Cu- and V-centered five-vertex polyhedra and PO{sub 4} tetrahedra. Channels in the [100] and [010] directions accommodate large K atoms and H{sub 2}O molecules. The compound is a new structural representative of the topology shown by the lavendulan group of copper arsenate and phosphate minerals. Their tetragonal or pseudotetragonal crystal structures are characterized by two types of 2D slabs alternating along one axis of their unit cells. One slab, described by the formula [Cu{sub 4}X(TO{sub 4}){sub 4}]{sub 8} (where X = Cl, O and T = As, P), is common to all phases, whereas the slab content of the other set differs among the group members. We suggest interpreting this family of compounds in terms of the modular concept and also consider the synthetic phase Ba(VO)Cu{sub 4}(PO{sub 4}){sub 4} as a simplest member of this polysomatic series.

  7. Microwave-assisted hydrothermal synthesis of CePO{sub 4} nanostructures: Correlation between the structural and optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Palma-Ramírez, D. [Instituto Politécnico Nacional, CICATA-Unidad Altamira, Km 14.5, Carretera Tampico-Puerto Industrial Altamira, C.P. 89600 Altamira, Tamps (Mexico); Domínguez-Crespo, M.A., E-mail: mdominguezc@ipn.mx [Instituto Politécnico Nacional, CICATA-Unidad Altamira, Km 14.5, Carretera Tampico-Puerto Industrial Altamira, C.P. 89600 Altamira, Tamps (Mexico); Torres-Huerta, A.M. [Instituto Politécnico Nacional, CICATA-Unidad Altamira, Km 14.5, Carretera Tampico-Puerto Industrial Altamira, C.P. 89600 Altamira, Tamps (Mexico); Dorantes-Rosales, H. [Instituto Politécnico Nacional, ESIQIE, Departamento de Metalurgia, C.P. 07300 México D.F. (Mexico); Ramírez-Meneses, E. [Universidad Iberoamericana, Departamento de Ingeniería y Ciencias Químicas, Prolongación Paseo de la Reforma 880, Lomas de Santa Fe, C.P. 01219 México D.F. (Mexico); Rodríguez, E. [Instituto Politécnico Nacional, CICATA-Unidad Altamira, Km 14.5, Carretera Tampico-Puerto Industrial Altamira, C.P. 89600 Altamira, Tamps (Mexico)

    2015-09-15

    Highlights: • An enhancement in the hydrothermal synthesis for obtaining of CePO{sub 4} is presented. • Microwave energy can replace the energy by convection for obtaining CePO{sub 4}. • CePO{sub 4} demonstrates to be an option to increase the optical properties of polymers. • Adjusting the pH, the sintering process is not necessary to obtain the desire phase. • CePO{sub 4} morphologies undergo evolution from nanorods to semispherical nanoparticles. - Abstract: In this work, the microwave-assisted hydrothermal method is proposed as an alternative to the synthesis of cerium phosphate (CePO{sub 4}) nanostructures to evaluate the influence of different synthesis parameters on both the structural and optical properties. In order to reach this goal, two different sets of experiments were designed, varying the reaction temperature (130 and 180 °C), synthesis time (15 and 30 min) and sintering temperature (400 and 600 °C), maintaining a constant pH = 3. Thereafter, two experimental conditions were selected to assess changes in the properties of CePO{sub 4} nanopowders with pH (1, 5, 9 and 11). The crystal structure and morphology of the nanostructures were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM), respectively. Diffuse reflectance properties of CePO{sub 4} with different microstructures were studied. The results demonstrated that by using the microwave-assisted hydrothermal method, the shape, size and structural phase of CePO{sub 4} can be modulated by using relatively low synthesis temperatures and short reaction times, and depending on pH, a sintering process is not needed to obtain either a desired phase or size. Under the selected experimental conditions, the materials underwent an evolution from nanorods to semispherical nanoparticles, accompanied by a phase transition from hexagonal to monoclinic.

  8. HYDROTHERMAL SYNTHESIS AND CHARACTERIZATION OF A ...

    African Journals Online (AJOL)

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    tool for the construction of materials containing unique structures and special ... Recently, we reported hydrothermal synthesis of binuclear Co(II) complex [19] and a new .... to two neighboring ones, through four µ2-oxo bridges, to form infinite ...

  9. Two new cobalt-zinc orthophosphate monohydrates: hydrothermal synthesis, crystal structures and thermal investigation.

    Science.gov (United States)

    Sørensen, Morten B; Hazell, Rita G; Bentien, Anders; Bond, Andrew D; Jensen, Torben R

    2005-02-07

    Two new cobalt zinc orthophosphate hydrates with similar chemical formula, (CoxZn(1-x))3(PO4)2.H2O, but different composition and structure, have been prepared by systematic hydrothermal synthesis from the system nCo(CH3COO)2 : (1 -n)Zn(CH(3)COO)2 : 3.5H3PO4 : 2.1(CH3)2NH(CH2)3NH2:144H2O (0 project. Magnetic susceptibility measurements for 1 and 2 are consistent with the chemical compositions determined by the single-crystal X-ray analyses and with the presence of Co2+. The range for possible Co/Zn substitution in 1 and 2(assessed by EDX analysis) is relatively small: x lies in the range 0.74-0.80 (+/- 0.05) for 1 and 0.23-0.28 (+/- 0.05) for 2. Thermal investigation of 1 and 2 by thermogravimetry (TG), differential thermal analysis (DTA) and differential scanning calorimetry (DSC) shows that both materials transform to gamma-(CoxZn(1-x))3(PO4)2 when heated to 518 and 435 degrees C, respectively, with enthalpy changes for complete dehydration of DeltaH= 41.9 and 53.5 kJ mol(-1), respectively. Dehydration of 1 occurs in a single irreversible step, while that of 2 occurs over a greater temperature range and proceeds via several steps. A new phase, (CoxZn(1-x))3(PO4)2.0.27H2O, is formed when 2 is heated to 357 degrees C.

  10. Hydrothermal synthesis of hydroxyapatite

    Science.gov (United States)

    Earl, J. S.; Wood, D. J.; Milne, S. J.

    2006-02-01

    A hydrothermal method of synthesizing hydroxyapatite by heating a precipitate, formed by mixing Ca(NO3)2bold dot4H2O and (NH4)2HPO4 with distilled water, in a hydrothermal reactor at 200 °C for 24-72 hrs is described. A treatment time of 24 hrs produced single phase (as shown by XRD) hydroxyapatite powder, however for longer treatment times XRD patterns were indicative of the presence of a secondary phase, monetite (CaHPO4). SEM examination of the treated powders displayed particles of rod-like morphology with dimensions 100-500 nm in length and 10-60 nm in diameter. Preliminary results on the use of the particles for the infiltration of dentine tubules are presented.

  11. Hydrothermal synthesis of hydroxyapatite

    Energy Technology Data Exchange (ETDEWEB)

    Earl, J S; Wood, D J; Milne, S J [Institute for Materials Research, University of Leeds, Leeds, LS2 9JT (United Kingdom)

    2006-02-22

    A hydrothermal method of synthesizing hydroxyapatite by heating a precipitate, formed by mixing Ca(NO{sub 3}){sub 2}{center_dot}4H{sub 2}O and (NH{sub 4}){sub 2}HPO{sub 4} with distilled water, in a hydrothermal reactor at 200 deg. C for 24-72 hrs is described. A treatment time of 24 hrs produced single phase (as shown by XRD) hydroxyapatite powder, however for longer treatment times XRD patterns were indicative of the presence of a secondary phase, monetite (CaHPO{sub 4}). SEM examination of the treated powders displayed particles of rod-like morphology with dimensions 100-500 nm in length and 10-60 nm in diameter. Preliminary results on the use of the particles for the infiltration of dentine tubules are presented.

  12. Hydrothermal synthesis, structure and characterization of new NASICON related potassium iron (III) pyrophosphate

    Indian Academy of Sciences (India)

    G S Gopalakrishna; B H Doreswamy; M J Mahesh; M Mahendra; M A Sridhar; J Shashidhara Prasad; K G Ashamanjari

    2005-02-01

    A new potassium iron (III) pyrophosphate was synthesized by hydrothermal technique and characterized by X-ray studies. The compound crystallizes in a monoclinic space group, 21/, with cell parameters, = 7.365(2) Å, = 10.017(2) Å, = 8.214(1) Å, = 106.50(1)° and = 4. The structure has tunnel-type cavities and are congenial for ion transportation through them. The compound exhibits moderate thermal stability.

  13. Microwave Hydrothermal Synthesis PZT of Nanometer Crystal

    Institute of Scientific and Technical Information of China (English)

    Hongxing LIU; Hong DENG; Yan LI; Yanrong LI

    2004-01-01

    It was focused on the applications and developments of microwave hydrothermal synthesis piezoelectric ceramic powder. The microwave hydrothermal vessel was designed and manufactured. The microwave hydrothermal synthesis system was established and the PZT piezoelectric ceramic powder was synthesized. XRD and TEM have been used to characterize the products in detail. The diameter of the PZT powder particle is from 40 to 60 nm.

  14. STRUCTURE CONTROL IN HYDROXYAPATITE SYNTHESIS BY HYDROTHERMAL REACTION AND ORGANIC MODULATORS

    Institute of Scientific and Technical Information of China (English)

    Huigang Zhang; Qingshan Zhu

    2005-01-01

    Properties of materials are determined not only by their composition, but also by their structure. It is,therefore, of great significance to develop the ability of tailoring the structure of materials according to the requirements of intended applications. In this work a novel glutamic acid-assisted hydrothermal process was developed to synthesize apatite crystals with controllable morphologies. Varied morphologies from whisk broom, fibers, mushroom, prickly spheres, to dandelion were produced through modulating both the formation of a transitory phase and its transformation into the final phase.

  15. Amino acids assisted hydrothermal synthesis of hierarchically structured ZnO with enhanced photocatalytic activities

    Science.gov (United States)

    Guo, Yanxia; Lin, Siwen; Li, Xuan; Liu, Yuping

    2016-10-01

    Novel hierarchically structured ZnO, including rose-like, dandelion-like and flower-like, have been synthesized through a simple hydrothermal process using different amino acids (glutamine, histidine and glycine) as structure-directing agents and urea as deposition agent, followed by subsequent calcination. Amino acids played a crucial role in the formation of hierarchically structured ZnO, and different amino acids could induce different exquisite shapes and assembly ways, as well as more oxygen defects. The prepared hierarchically structured ZnO exhibited excellent photocatalytic activities for the photodegradation of Rhodamine B, which was associated with their special hierarchical structures, large BET surface area and the existence of more oxygen defects. Amino acid-assisted growth mechanism of hierarchically structured ZnO was also discussed.

  16. Hydrothermal organic synthesis experiments

    Science.gov (United States)

    Shock, Everett L.

    1992-01-01

    The serious scientific debate about spontaneous generation which raged for centuries reached a climax in the nineteenth century with the work of Spallanzani, Schwann, Tyndall, and Pasteur. These investigators demonstrated that spontaneous generation from dead organic matter does not occur. Although no aspects of these experiments addressed the issue of whether organic compounds could be synthesized abiotically, the impact of the experiments was great enough to cause many investigators to assume that life and its organic compounds were somehow fundamentally different than inorganic compounds. Meanwhile, other nineteenth-century investigators were showing that organic compounds could indeed be synthesized from inorganic compounds. In 1828 Friedrich Wohler synthesized urea in an attempt to form ammonium cyanate by heating a solution containing ammonia and cyanic acid. This experiment is generally recognized to be the first to bridge the artificial gap between organic and inorganic chemistry, but it also showed the usefulness of heat in organic synthesis. Not only does an increase in temperature enhance the rate of urea synthesis, but Walker and Hambly showed that equilibrium between urea and ammonium cyanate was attainable and reversible at 100 C. Wohler's synthesis of urea, and subsequent syntheses of organic compounds from inorganic compounds over the next several decades dealt serious blows to the 'vital force' concept which held that: (1) organic compounds owe their formation to the action of a special force in living organisms; and (2) forces which determine the behavior of inorganic compounds play no part in living systems. Nevertheless, such progress was overshadowed by Pasteur's refutation of spontaneous generation which nearly extinguished experimental investigations into the origins of life for several decades. Vitalism was dealt a deadly blow in the 1950's with Miller's famous spark-discharge experiments which were undertaken in the framework of the Oparin

  17. Structural study of the controlled hydrothermal synthesis of LiMn2O4 and LixMnyO2

    DEFF Research Database (Denmark)

    Christiansen, Troels Lindahl; Jensen, Kirsten Marie Ørnsbjerg; Shen, Yanbin

    LiMn2O4 , which crystallizes in the spinel structure, is of great interest as a cathode material for Li-ion batteries due to the high natural abundance of manganese, low toxicity, fast ionic diffusion and excellent battery capabilities. The structure is closely related to that of LixMnyO2......, a layered structure, which can also be described as a defective spinel structure. Here, we show that both LiMn2O4 and LixMnyO2 nanoparticles can be synthesized from a simple, low-temperature hydrothermal synthesis. By tuning a single synthesis parameter (Li-concentration) each of the 2 structures...... or mixtures hereof can be obtained. The products have been characterized by X-ray powder diffraction both in-house and at SPring-8. Rietveld refinement was carried out on the high-resolution data from the synchrotron source and detailed structural models for both the spinel and the layered phase were obtained...

  18. Hydrothermal synthesis and photoelectrochemical properties of In2S3 thin films with a wedgelike structure

    Science.gov (United States)

    Zhang, Lina; Zhang, Wei; Yang, Haibin; Fu, Wuyou; Li, Minghui; Zhao, Hui; Ma, Jinwen

    2012-09-01

    Indium sulfide (In2S3) thin films with a wedgelike structure were prepared on fluorine-doped tin oxide (FTO) substrate by a facile hydrothermal method. By properly monitoring the experimental conditions, including the reaction time, concentrations of tartaric acid, precursor concentration ratio and the reaction temperature, the In2S3 films with different morphologies and thickness could be obtained, and the growth mechanism of β-In2S3 films was also proposed in this work. Furthermore, UV-vis absorption study revealed that the absorption range broadened with the growth of the In2S3 crystals. In addition, a photocurrent of 0.48 mA cm-2 was obtained under 100 mW cm-2 UV-visible illuminations of the wedgelike In2S3 thin films.

  19. Synthesis and Optical Properties of SnO2 Structures with Different Morphologies via Hydrothermal Method

    Science.gov (United States)

    Wang, Jing; Fan, Hui-qing; Yu, Hua-wa; Wang, Xin

    2015-09-01

    SnO2 nanosheets with sizes around 1 μm and thickness around 30 nm have been synthesized by a template-free hydrothermal method. With the addition of urea, SnO2 hollow microspheres with diameters of about 1 μm and shell thickness of about 200 nm were also prepared. The structures, morphologies, and optical properties of the as-prepared samples were characterized by x-ray diffraction, scanning electron microscopy, transmission electron microscopy and selected area electron diffraction, Raman spectroscopy, and ultraviolet-visible absorption spectrophotometry. The possible mechanisms for the growth of these SnO2 nanostructures were tentatively proposed based on controlled experiments. Moreover, photocatalytic investigations revealed that the as-prepared SnO2 samples possessed good photocatalytic activity in the degradation of rhodamine B.

  20. Synthesis and photocatalysis properties of ZnO structures with different morphologies via hydrothermal method

    Science.gov (United States)

    Xie, Juan; Wang, Hu; Duan, Ming; Zhang, Liehui

    2011-05-01

    The special flower-like and sheet-like ZnO structures were successfully synthesized by hydrothermal method. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). The photocatalytic activity of different morphologies of ZnO structures was evaluated by degradating of methyl orange (MO). The photocatalytic degradation process was monitored in terms of decolorization and total organic carbon (TOC) removals. The results indicated that the flower-like ZnO structures were consisted of numerous flower-like aggregates with the size of 2 μm. The sheet-like ZnO nanostructures were obtained by increasing the reaction time. They exhibited higher photodegradation efficiencies under UV light irradiation than flower-like ZnO structures due to the blue shift of the band gap. The photodegradation could be described as the pseudo-first-order kinetics with apparent rate constants ranging from 1.17 × 10 -2 to 3.42 × 10 -2 min -1, which were based on the morphology of the structures. The photodegradation was faster than the mineralization, indicating that the accumulation of by-products were resistant to photocatalytic degradation.

  1. Hydrothermal Synthesis, Crystal Structure and Electrochemical Behavior of 2d Hybrid Coordination Polymer

    Science.gov (United States)

    Fan, Weiqiang; Zhu, Lin; Shi, Weidong; Chen, Fuxiao; Bai, Hongye; Song, Shuyan; Yan, Yongsheng

    2013-06-01

    A novel metal-organic coordination polymer [Cu(phen)(L)0.5(H2O)]n (H4L = (N,N‧-5,5‧-bis(isophthalic acid)-p-xylylenediamine, and phen = 1,10-phenanthroline) has been hydrothermally synthesized and characterized by elemental analysis, IR, TGA, and single-crystal X-ray diffraction. The crystallographic data show that the title compound crystallizes in monoclinic space group P21/n with a = 10.682(2), b = 15.682(3), c = 11.909(2) Å, β = 91.39(3)°, V = 1994.3(7) Å3, C24H17CuN3O5, Mr = 490.95, Dc = 1.635 g/cm3, F(000) = 1004, Z = 4, μ(MoKα) = 1.141 mm-1, the final R = 0.0418 and wR = 0.0983 for 3578 observed reflections (I > 2σ(I)). The structural analyses reveal that the title compound exhibits shows a 2D layer structure, which are further linked by hydrogen bonding interactions to form a three-dimensional supramolecular network. In addition, the thermal stability and electrochemical behavior of title compound has been studied. CCDC: 900413.

  2. Microwave-Assisted Hydrothermal Rapid Synthesis of Calcium Phosphates: Structural Control and Application in Protein Adsorption

    Directory of Open Access Journals (Sweden)

    Zhu-Yun Cai

    2015-07-01

    Full Text Available Synthetic calcium phosphate (CaP-based materials have attracted much attention in the biomedical field. In this study, we have investigated the effect of pH values on CaP nanostructures prepared using a microwave-assisted hydrothermal method. The hierarchical nanosheet-assembled hydroxyapatite (HAP nanostructure was prepared under weak acidic conditions (pH 5, while the HAP nanorod was prepared under neutral (pH 7 and weak alkali (pH 9 condition. However, when the pH value increases to 11, a mixed product of HAP nanorod and tri-calcium phosphate nanoparticle was obtained. The results indicated that the pH value of the initial reaction solution played an important role in the phase and structure of the CaP. Furthermore, the protein adsorption and release performance of the as-prepared CaP nanostructures were investigated by using hemoglobin (Hb as a model protein. The sample that was prepared at pH = 11 and consisted of mixed morphologies of nanorods and nanoprisms showed a higher Hb protein adsorption capacity than the sample prepared at pH 5, which could be explained by its smaller size and dispersed structure. The results revealed the relatively high protein adsorption capacity of the as-prepared CaP nanostructures, which show promise for applications in various biomedical fields such as drug delivery and protein adsorption.

  3. Hydrothermal Synthesis and Crystal Structure of a New Hexa-cobalt-containing POM

    Institute of Scientific and Technical Information of China (English)

    FU Chun-Hua; ZHENG Shou-Tian; YANG Guo-Yu

    2008-01-01

    A new compound Na3H3[Co(en)3]2[Co4(H2O)2(PW9O34)2]·11H2O 1 (en = ethylene- diamine) has been synthesized under hydrothermal conditions and characterized by IR, TGA, and single-crystal X-ray diffraction analysis. Crystal data: monoclinic, space group C2/c, a = 26.336(5), b = 18.135(2), c = 22.751(4) A, β = 123.039(7)° and Z = 4. X-ray crystallographic study on compound 1 reveals that it includes a Weakley-type sandwich polyoxoanion [Co4(H2O)2(PW9O34)2]10-, two complex ions [Co(en)3]2+, three Na+ ions (one Na(1) and two Na(2)), and eleven crystallographic water molecules. The sandwich polyoxoanions are linked by Na2 to form 2D layers parallel to the (100) plane, and these layers are further connected by Nal along the a-axis to generate a 3D structure.

  4. Hydrothermal synthesis and crystal structure of a new lanthanum(III coordination polymer with fumaric acid

    Directory of Open Access Journals (Sweden)

    Hayet Anana

    2015-05-01

    Full Text Available The title compound, poly[diaquatris(μ4-but-2-enedioato(μ2-but-2-enedioic aciddilanthanum(III], [La2(C4H2O43(C4H4O4(H2O2]n, was synthesized by the reaction of lanthanum chloride pentahydrate with fumaric acid under hydrothermal conditions. The asymmetric unit comprises an LaIII cation, one and a half fumarate dianions (L2−, one a half-molecule of fumaric acid (H2L and one coordinated water molecule. Each LaIII cation has the same nine-coordinate environment and is surrounded by eight O atoms from seven distinct fumarate moieties, including one protonated fumarate unit and one water molecule in a distorted tricapped trigonal–prismatic environment. The LaO8(H2O polyhedra centres are edge-shared through three carboxylate bridges of the fumarate ligand, forming chains in three dimensions to construct the MOF. The crystal structure is stabilized by O—H...O hydrogen-bond interactions between the coordinated water molecule and the carboxylate O atoms, and also between oxygen atoms of fumaric acid

  5. Hydrothermal synthesis of mixed zinc-cobalt ferrite nanoparticles: structural and magnetic properties

    Science.gov (United States)

    Coppola, P.; da Silva, F. G.; Gomide, G.; Paula, F. L. O.; Campos, A. F. C.; Perzynski, R.; Kern, C.; Depeyrot, J.; Aquino, R.

    2016-05-01

    We synthesize Zn-substituted cobalt ferrite (Zn x Co1- x Fe2O4, with 0 ≤ x ≤ 1) magnetic nanoparticles by a hydrothermal co-precipitation method in alkaline medium. The chemical composition is evaluated by atomic absorption spectroscopy and energy-dispersive X-ray spectroscopy techniques. The structure and morphology of the nanopaticles are investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. XRD Rietveld refinements reveal the cation distribution among the tetrahedral (A) and octahedral (B) sites. It shows that up to x 0.5 zinc ions occupy preferably A-sites, above which Zn ions begin also a gradual occupancy of B-sites. TEM images show nanoparticles with different shapes varying from spheres, cubes, to octahedrons. Hysteresis loop properties are studied at 300 and 5 K. These properties are strongly influenced by the Zn and Co proportion in the nanoparticle composition. At 300 K, only samples with high Co content present hysteresis. At 5 K, the reduced remanent magnetization ratio ( M R/ M S) and the coercivity ( H C) suggest that nanoparticles with x < 0.5 have cubic anisotropy. A kink on the hysteresis loop, close to the remanence, is observed at low temperature. This feature is presumably associated to interplay between hard and soft anisotropy regimes in the powder samples.

  6. Hydrothermal Synthesis and Structural Characterization of Novel Zn-Triazole-Benzenedicarboxylate Frameworks

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hyunsoo; Moureau, David M.; Parise, John B. (SBU)

    2008-10-03

    Three new metal-organic coordination polymers were synthesized hydrothermally using Zn2+ ion, 1,2,4-triazole, and 1,4-benzenedicarboxylic acid (BDC): Zn5(H2O)2(C2H2N3)4(C8H4O4)3 {center_dot} 3.9H2O (1), Zn2(C2H2N3)2(C2H3N3)(C8H4O4) {center_dot} 2.5H2O (2), and Zn4(H2O)2(C2H2N3)4(C8H4O4)2 {center_dot} 14H2O (3). Their crystal structures were determined by single-crystal X-ray diffraction. Their thermal properties were examined by thermogravimetric analysis. Structure 1 crystallizes in the monoclinic P21/n space group with a = 10.192(2) {angstrom}, b = 17.764(4) {angstrom}, c = 24.437(5) {angstrom}, {beta} = 91.19(3){sup o}, and V = 4423.3(15) {angstrom}3. Structure 2 crystallizes in the triclinic P space group with a = 7.797(2) {angstrom}, b = 10.047(2) {angstrom}, c = 13.577(3) {angstrom}, {alpha} = 110.18(3){sup o}, {beta} = 105.46(3){sup o}, {gamma} = 93.90(3){sup o}, and V = 947.0(3) {angstrom}3. Structure 3 crystallizes in monoclinic P21/n space group with a = 13.475(3) {angstrom}, b = 26.949(5) {angstrom}, c = 13.509(3) {angstrom}, {beta} = 95.18(3){sup o}, and V = 4885.7(17) {angstrom}3. In structure 1, the units of the triazole-Zn polyhedra are linked by BDC in a zigzag fashion to create the stacking of phenyl groups along the a axis. In structure 2, both triazole and BDC bridge Zn polyhedra in the (011) plane, resulting in the eight-membered channels along the a axis. In the case of structure 3, the BDC links the Zn polyhedra along the b axis to form a pillared open framework. This structure is the most porous of the compounds presented in this work.

  7. Biomolecule-Assisted Hydrothermal Synthesis and Self-Assembly of Bi2Te3 Nanostring-Cluster Hierarchical Structure

    DEFF Research Database (Denmark)

    Mi, Jianli; Lock, Nina; Sun, Ting;

    2010-01-01

    A simple biomolecule-assisted hydrothermal approach has been developed for the fabrication of Bi2Te3 thermoelectric nanomaterials. The product has a nanostring-cluster hierarchical structure which is composed of ordered and aligned platelet-like crystals. The platelets are100 nm in diameter...

  8. Hydrothermal Synthesis, Crystal Structure, Spectrum and Electrochemical Analysis of the Copper(Ⅱ) Coordination Polymer

    Institute of Scientific and Technical Information of China (English)

    LI Chang-Hong; LI Wei; LI Yu-Lin; KUANG Yun-Fei

    2012-01-01

    The three-dimensional framework copper(Ⅱ) coordination polymer with basic copper carbonate and 3-(pyridin-2-yl)-1,2,4-triazole has been hydrothermally synthesized. It crystallizes in monoclinic space group P21/c, with a = 1.20860(3), b = 1.29581(2), c = 1.67863(3) nm, β = 116.0280(2)°, C21H12Cu3N12, Mr = 623.05, V = 2.36230(9) nm3, Dc = 1.752 g/cm3, Z = 4, F(000) = 1236, GOOF = 1.037, the final R = 0.0408 and wR = 0.1141. Every unit cell contains three copper atoms and three 3-(pyridin-2-yl)-1,2,4-triazole ligands. Every central Cu(Ⅱ) ion is coordinated by four nitrogen atoms of the 3-(pyridin-2-yl)-1,2,4-triazole ligands, forming a distorted tetrahedron. The title complex exhibits an intense photoluminescence at room temperature with the maximum emission at 392 nm. The cyclic voltametric behavior of the complex shows that the electron transfer in electrolysis reaction is irreversible.

  9. Hydrothermal Synthesis and Crystal Structure of Trioxomolybdate: NaH3OMo3O1O

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The hydrothermal reaction of Na2MoO4·2H2O, SmCl3 in acidified H2O/CH3CN solution gives rise to the title compound as colorless needle crystals, which was characterized by elemental analysis, IR and X-ray single-crystal diffraction techniques. Crystallographic data: Orthorhombic, Pnma, H3Mo3NaO11, Mr. = 489.83, a = 8.411(2), b = 7.566(2), c = 14.359(3) A, V= 913.8(3) A3, Z = 4, De = 3.560 g·cm-3,μ = 4.148 mm-1, F(000) = 912, the final R = 0.0649 and wR = 0.1569 for 1885 observed reflections with I ≥ 2σ (I). The title compound consists of infinite chains built up by distorted {MOO6} octahedra via edge sharing, which are further connected into a three-dimensional framework by sodium ions and protoned water molecules.

  10. Metal oxide and hydroxide nanoarrays: Hydrothermal synthesis and applications as supercapacitors and nanocatalysts

    National Research Council Canada - National Science Library

    Qiu Yang Zhiyi Lu Junfeng Liu Xiaodong Lei Zheng Chang Liang Luo Xiaoming Sun

    2013-01-01

    ... synthesis.This article reviews recent progress in our laboratory related to the hydrothermal synthesis of metal oxide and hydroxide nanoarrays,whose structures are designed aiming to the application on super...

  11. Peptide synthesis in early earth hydrothermal systems

    Science.gov (United States)

    Lemke, K.H.; Rosenbauer, R.J.; Bird, D.K.

    2009-01-01

    We report here results from experiments and thermodynamic calculations that demonstrate a rapid, temperature-enhanced synthesis of oligopeptides from the condensation of aqueous glycine. Experiments were conducted in custom-made hydrothermal reactors, and organic compounds were characterized with ultraviolet-visible procedures. A comparison of peptide yields at 260??C with those obtained at more moderate temperatures (160??C) gives evidence of a significant (13 kJ ?? mol-1) exergonic shift. In contrast to previous hydrothermal studies, we demonstrate that peptide synthesis is favored in hydrothermal fluids and that rates of peptide hydrolysis are controlled by the stability of the parent amino acid, with a critical dependence on reactor surface composition. From our study, we predict that rapid recycling of product peptides from cool into near-supercritical fluids in mid-ocean ridge hydrothermal systems will enhance peptide chain elongation. It is anticipated that the abundant hydrothermal systems on early Earth could have provided a substantial source of biomolecules required for the origin of life. Astrobiology 9, 141-146. ?? 2009 Mary Ann Liebert, Inc. 2009.

  12. Hydrothermal synthesis, structure and photocatalytic property of nano-TiO2-MnO2

    Institute of Scientific and Technical Information of China (English)

    DING; Shiwen(丁士文); WANG; Liyong(王利勇); ZHANG; Shaoyan(张绍岩); ZHOU; Qiuxiang(周秋香); DING; Yu(丁宇); LIU; Shujuan(刘淑娟); LIU; Yanchao(刘燕朝); KANG; Quanying(康全影)

    2003-01-01

    TiCl4 and MnSO4·H2O as raw materials are hydrolyzed stiochiometrically, following the intermediate of oxide hydrating reacts at 150℃, 0.5 Mpa in high-pressure reactor, after filtering, washing and drying, nanometric TiO2-MnO2 (Ti1-xMnxO2) is prepared. The effects of the reaction temperature and time on nanometric TiO2-MnO2 are also discussed. XRD shows that the product is TiO2-MnO2 with amorphous phase. After being sintered at above 780℃, it transfers into Ti1-xMnxO2 with a rutile structure. TEM shows that TiO2-MnO2 is the spherical particle. And the average diameter of the particles is 20 nm. The optical absorbance was determined by UV-265 spectrophotometer after dispersing the sample in the mixture of water and glycerol with the ratio of 1︰1 equably. It is found that the nano-material possesses the advantages of both nano-TiO2 and nano-MnO2, and it has strong absorption in the UV and visible region. Photodegradation of dyes in an aqueous solution is investigated using nanometricTiO2-MnO2 as a photocatalyst. The results show that after 60 min illumination, the decolorization rate of the acidic red B and acidic black 234 dye can be as high as 100%.

  13. Zinc stannate nanostructures: hydrothermal synthesis

    Directory of Open Access Journals (Sweden)

    Sunandan Baruah and Joydeep Dutta

    2011-01-01

    Full Text Available Nanostructured binary semiconducting metal oxides have received much attention in the last decade owing to their unique properties rendering them suitable for a wide range of applications. In the quest to further improve the physical and chemical properties, an interest in ternary complex oxides has become noticeable in recent times. Zinc stannate or zinc tin oxide (ZTO is a class of ternary oxides that are known for their stable properties under extreme conditions, higher electron mobility compared to its binary counterparts and other interesting optical properties. The material is thus ideal for applications from solar cells and sensors to photocatalysts. Among the different methods of synthesizing ZTO nanostructures, the hydrothermal method is an attractive green process that is carried out at low temperatures. In this review, we summarize the conditions leading to the growth of different ZTO nanostructures using the hydrothermal method and delve into a few of its applications reported in the literature.

  14. CTAB-Assisted Hydrothermal Synthesis of WO3 Hierarchical Porous Structures and Investigation of Their Sensing Properties

    Directory of Open Access Journals (Sweden)

    Dan Meng

    2015-01-01

    Full Text Available WO3 hierarchical porous structures were successfully synthesized via cetyltrimethylammonium bromide- (CTAB- assisted hydrothermal method. The structure and morphology were investigated using scanning electron microscope, X-ray diffractometer, transmission electron microscopy, X-ray photoelectron spectra, Brunauer-Emmett-Teller nitrogen adsorption-desorption, and thermogravimetry and differential thermal analysis. The result demonstrated that WO3 hierarchical porous structures with an orthorhombic structure were constructed by a number of nanoparticles about 50–100 nm in diameters. The H2 gas sensing measurements showed that well-defined WO3 hierarchical porous structures with a large specific surface area exhibited the higher sensitivity compared with products without CTAB at all operating temperatures. Moreover, the reversible and fast response to H2 gas and good selectivity were obtained. The results indicated that the WO3 hierarchical porous structures are promising materials for gas sensors.

  15. Hydrothermal synthesis of nanostructured hybrids based on iron oxide and branched PEI polymers. Influence of high pressure on structure and morphology

    Energy Technology Data Exchange (ETDEWEB)

    Popescu, L.M., E-mail: mpopescu@imnr.ro [National R& D Institute for Non-ferrous and Rare Metals, 102 Biruintei Blvd, Pantelimon, Judetul Ilfov (Romania); Piticescu, R.M., E-mail: roxana@imnr.ro [National R& D Institute for Non-ferrous and Rare Metals, 102 Biruintei Blvd, Pantelimon, Judetul Ilfov (Romania); Petriceanu, M., E-mail: mirelap@imnr.ro [National R& D Institute for Non-ferrous and Rare Metals, 102 Biruintei Blvd, Pantelimon, Judetul Ilfov (Romania); Ottaviani, M.F., E-mail: maria.ottaviani@uniurb.it [University of Urbino “Carlo Bo”, Department of Earth, Life and Environmental Sciences, Urbino (Italy); Cangiotti, M., E-mail: michela.cangiotti@uniurb.it [University of Urbino “Carlo Bo”, Department of Earth, Life and Environmental Sciences, Urbino (Italy); Vasile, E., E-mail: eugeniuvasile@yahoo.com [University Politehnica of Bucharest, Bucharest (Romania); National R& D Institute for Non-ferrous and Rare Metals, 102 Biruintei Blvd, Pantelimon, Judetul Ilfov (Romania); Dîrtu, M.M., E-mail: marinela.dirtu@uclouvain.be [Institute of Condensed Mater and Nanosciences, Molecules, Solids and Reactivity (IMCN/MOST), Université Catholique de Louvain, Place L. Pasteur 1, 1348 Louvain-la-Neuve (Belgium); Wolff, M., E-mail: mariusz.wolff@uclouvain.be [Institute of Condensed Mater and Nanosciences, Molecules, Solids and Reactivity (IMCN/MOST), Université Catholique de Louvain, Place L. Pasteur 1, 1348 Louvain-la-Neuve (Belgium); Garcia, Y., E-mail: yann.garcia@uclouvain.be [Institute of Condensed Mater and Nanosciences, Molecules, Solids and Reactivity (IMCN/MOST), Université Catholique de Louvain, Place L. Pasteur 1, 1348 Louvain-la-Neuve (Belgium); and others

    2015-07-01

    Homogeneous hybrids in which iron oxide nanoparticles are entrapped within polymer structure are of interest for their potential applications in biomedical field, such as diagnostic, therapeutic and theranostic purposes. For this reason, hybrid nanomaterials based on branched polyethyleneimine (PEI) and iron oxide with different ratios were synthesized in a single step by hydrothermal procedure at high pressure and low temperature. Iron oxide is formed in the presence of branched PEI and the interaction between them takes place in the reaction medium. The influence of synthesis parameters on the hybrid formation, as well as chemical and structural properties was studied by means of FTIR, DSC-TG, HRTEM, electron paramagnetic resonance (EPR), magnetic measurements (SQUID) and {sup 57}Fe Mössbauer analyses. It has been shown that synthesis parameters influence thermal stability and morphology of the hybrids. FeO(OH) crystallites of 2–5 nm are formed. Iron oxyhydroxide nanoparticles strongly entrapped in PEI structure are obtained. The low and distributed values of the specific spontaneous magnetisation in samples prepared under the same pressure conditions support the presence of very fine FeO(OH) nanoparticles, which formation and magnetic properties are depending on the mass ratio between iron oxide and PEI. - Highlights: • Polyethyleneimine (PEI) – iron oxide hybrids were synthesized by hydrothermal method. • Synthesis parameters influence thermal stability and morphology of the hybrids. • Small crystallites of FeO(OH) with size between 2 and 5 nm are formed. • Formation of stable hybrid nanostructures in the pressure range 1000–3000 atm. • FeO(OH) nanoparticles are entrapped in PEI structure at low inorganic–organic ratio.

  16. One-step hydrothermal synthesis of highly water-soluble secondary structural Fe{sub 3}O{sub 4} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Yang Xiwen [National Special Superfine Powder Engineering Research Center, Nanjing University of Science and Technology, Nanjing 210094 (China); Jiang Wei, E-mail: yangxw0610@yahoo.cn [National Special Superfine Powder Engineering Research Center, Nanjing University of Science and Technology, Nanjing 210094 (China); Liu Li; Chen Binghua; Wu Shixi; Sun Danping; Li Fengsheng [National Special Superfine Powder Engineering Research Center, Nanjing University of Science and Technology, Nanjing 210094 (China)

    2012-07-15

    Magnetite nanoparticles (MNPs) were prepared using the ferric acetylacetonate as the sole iron source in a facile hydrothermal route, while poly(acrylic acid) (PAA) was chosen as the stabilizer via one-step functionalized MNPs for better hydrophilic properties. The orthogonal was used in the paper for the experimental parameters optimization, including the solvent, the reaction time, the amount of stabilizer and the presynthesis. The obtained highly water dispersible MNPs with uniform size from about 50 to about 100 nm was individually composed of many monodisperse magnetite crystallites approximately 6 nm in size. And the MNPs show high magnetic properties, whose magnetite content was up to 76.76% and the saturation magnetization was 39.0 emu/g. Later the formation mechanism of MNPs was also discussed. Thus the MNPs proved to be very promising for biomedical applications. - Highlights: Black-Right-Pointing-Pointer MNPs are prepared in a low-temperature hydrothermal synthesis procedure. Black-Right-Pointing-Pointer Synthesis of MNPs is hybridized with their in situ surface functionalization. Black-Right-Pointing-Pointer Each of the secondary structural MNPs is composed of monodisperse primary particles. Black-Right-Pointing-Pointer The resulting MNPs show good magnetic properties combining that of primary one. Black-Right-Pointing-Pointer The size of MNPs is controllable and the mechanism is elaborated.

  17. Hydrothermal synthesis and crystal structure of a new lithium copper bismuth oxide, LiCuBiO4

    Science.gov (United States)

    Kumada, Nobuhiro; Nakamura, Ayumi; Miura, Akira; Takei, Takahiro; Azuma, Masaki; Yamamoto, Hajime; Magome, Eisuke; Moriyoshi, Chikako; Kuroiwa, Yoshihiro

    2017-01-01

    A new lithium copper bismuth oxide, LiCuBiO4 was prepared by hydrothermal reaction using NaBiO30.1*4H2O. The crystal structural model of this compound was refined by using synchrotron X-ray powder diffraction data. This bismuthate has the LiCuSbO4 related structure with the orthorhombic cell (Space group: Pnma) of a=10.9096(9), b=5.8113(5) and c=5.0073(4) Å, and the final R-factors were Rwp=4.84 and Rp=3.58%. This compound is the first example of a lithium copper bismuthate containing Bi5+. An antiferromagnetic ordering of Cu2+ moment was observed at 6 K.

  18. Hydrothermal Synthesis and Structure of [(PbCl2)(μ-Pyz)1/2]n (Pyz = Pyrazine)

    Institute of Scientific and Technical Information of China (English)

    LIAO Qiu-Xia; ZHANG Jian; QIN Ye-Yan; YAO Yuan-Gen

    2006-01-01

    A novel 2-D lead-containing hybrid compound, [(PbCl2)(μ-Pyz)1/2]n (Pyz = pyrazine) 1, has been synthesized by the hydrothermal assembly of pyrazine with lead chloride.Elemental analysis and X-ray crystal structure analyses were carried out for the structural determination and characterization of the title compound. Compound 1 crystallizes in orthorhombic,space group Ibam, with a = 19.5558(18), b = 7.1939(6), c = 7.5449(6) (A), V = 1061.44(16) (A)3,C2H2Cl2NPb, Mr= 318.14, Z = 8, Dc= 3.982 g/cm3,μ = 32.63 mm-1, F(000) = 1096.0, R = 0.0368and wR = 0.0901 for 623 observed reflections (1 > 2σ(Ⅰ)).

  19. Effect of deposition parameters on the structural properties of ZnO nanopowders prepared by microwave-assisted hydrothermal synthesis.

    Science.gov (United States)

    Caglar, Yasemin; Gorgun, Kamuran; Aksoy, Seval

    2015-03-05

    ZnO nanopowders were synthesized via microwave-assisted hydrothermal method at different deposition (microwave irradiation) times and pH values. The effects of pH and deposition (microwave irradiation) time on the crystalline structure and orientation of the ZnO nanopowders have been investigated by X-ray diffraction (XRD) study. XRD observations showed that the crystalline quality of ZnO nanopowders increased with increasing pH value. The crystallite size and texture coefficient values of ZnO nanopowders were calculated. The structural quality of ZnO nanopowder was improved by deposition parameters. Field emission scanning electron microscope (FESEM) was used to analyze the surface morphology of the ZnO nanopowders. Microwave irradiation time and pH value showed a significant effect on the surface morphology.

  20. Hydrothermal synthesis and photoelectrochemical properties of In{sub 2}S{sub 3} thin films with a wedgelike structure

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Lina [State Key Laboratory of Superhard Materials, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Zhang, Wei [Department of Materials Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Yang, Haibin, E-mail: yanghb@jlu.edu.cn [State Key Laboratory of Superhard Materials, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Fu, Wuyou; Li, Minghui; Zhao, Hui; Ma, Jinwen [State Key Laboratory of Superhard Materials, Jilin University, 2699 Qianjin Street, Changchun 130012 (China)

    2012-09-01

    Highlights: Black-Right-Pointing-Pointer Wedgelike In{sub 2}S{sub 3} films are synthesized on FTO substrate via a hydrothermal method. Black-Right-Pointing-Pointer Facile control the morphology and thickness of the films. Black-Right-Pointing-Pointer Tartaric acid play key role in the formation of In{sub 2}S{sub 3} films. Black-Right-Pointing-Pointer The wedgelike In{sub 2}S{sub 3} thin films exhibit higher photocurrent than previous reports. - Abstract: Indium sulfide (In{sub 2}S{sub 3}) thin films with a wedgelike structure were prepared on fluorine-doped tin oxide (FTO) substrate by a facile hydrothermal method. By properly monitoring the experimental conditions, including the reaction time, concentrations of tartaric acid, precursor concentration ratio and the reaction temperature, the In{sub 2}S{sub 3} films with different morphologies and thickness could be obtained, and the growth mechanism of {beta}-In{sub 2}S{sub 3} films was also proposed in this work. Furthermore, UV-vis absorption study revealed that the absorption range broadened with the growth of the In{sub 2}S{sub 3} crystals. In addition, a photocurrent of 0.48 mA cm{sup -2} was obtained under 100 mW cm{sup -2} UV-visible illuminations of the wedgelike In{sub 2}S{sub 3} thin films.

  1. Synthesis of crystalline perovskite-structured SrTiO3 nanoparticles using an alkali hydrothermal process

    Institute of Scientific and Technical Information of China (English)

    U.K.N. Din; T.H.T. Aziz; M.M. Salleh; A.A. Umar

    2016-01-01

    We report an experimental route for synthesizing perovskite-structured strontium titanate (SrTiO3) nanocubes using an alkali hydrothermal process at low temperatures without further heating. Furthermore, we studied the influence of heating time (at 180°C) on the crystallinity, morphology, and perovskite phase formation of SrTiO3. The SrTiO3 powder, which is formed via nanocube agglomeration, transforms into cubic particles with a particle size of 120–150 nm after 6 h of hydrothermal sintering. The crystallinity and percentage of the perovskite phase in the product increased with heating time. The cubic particles contained 31.24at% anatase TiO2 that originated from the precursor. By varying the weight ratio of anatase TiO2 used to react with the strontium salt precursor, we reduced the anatase-TiO2 content to 18.8at%. However, the average particle size increased when the anatase-TiO2 content decreased.

  2. Hydrothermal synthesis, crystal structure and properties of a novel chain coordination polymer constructed by tetrafunctional phosphonate anions and cobalt ions

    Energy Technology Data Exchange (ETDEWEB)

    Guan, Lei, E-mail: gl_coord@163.com [School of Chemistry and Materials Science, Liaoning University of Petroleum and Chemical Engineering, Fushun 113001 (China); Wang, Ying [Center of Experiment, College of Chemistry, Chemical Engineering and Environmental Engineering, Liaoning University of Petroleum and Chemical Engineering, Fushun 113001 (China)

    2015-08-15

    A novel cobalt phosphonate, [Co(HL)(H{sub 2}O){sub 3}]{sub n} (1) (L=N(CH{sub 2}PO{sub 3}H){sub 3}{sup 3−}) has been synthesized by hydrothermal reaction at 150 °C and structurally characterized by X-ray diffraction, infrared spectroscopy, elemental and thermogravimetric analysis. Complex 1 features a 1D chain structure with double-channel built from CoO{sub 6} octahedra bridged together by the phosphonate groups. Each cobalt ion is octahedrally coordinated by three phosphonate oxygen atoms and three water molecules. The coordinated water molecules can form the hydrogen bonds with the phosphonate oxygen atoms to link the 1D chains, building a 2D layered structure, further resulting in a 3D network. The luminescence spectrum indicates an emission maximum at 435 nm. The magnetic susceptibility curve exhibits a dominant antiferromagnetic behavior with a weakly ferromagnetic component at low temperatures. - Graphical abstract: The connectivity between cobalt ions and the ligands results in a chain structure with a 1D double-channel structure, which is constructed by A-type subrings and B-type subrings. - Highlights: • The tetrafunctional phosphonate ligand was used as the ligand. • A novel chain structure can be formed by A-type rings and B-type rings. • Two types of rings can form a 1D double-channel structure, along the c-axis.

  3. Hydrothermal Synthesis, Crystal Structure, and Characterization of a Novel Terbium(Ⅲ) Coordination Polymer Bridged by 5-Sulfoisophthalate Trivalent Anions

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Hydrothermal reaction of terbium( Ⅲ ) chloride with 5-sulfoisophthalic acid monosodium salt and 1, 10-phenanthroline(phen) at 415 K resulted in the formation of a novel coordination polymer, [Tb(sip) (phen) (H2O)]n( sip = 5-sulfoisophthalate trivalent anion) with a three-dimensional network structure. Each centrosymmetrically related pair of terbium ions are linked by two sip anions, forming a binuclear unit, and each binuclear unit links to four adjacent tetranuclear units, extending a two-dimensional hybrid layer at crystallographic bc plane. On the other hand,every three-terbium ion is connected by three sip anions, generating a trinuclear ring, and the trinuclear ring connects six neighboring trinuclear rings to produce another two-dimensional layer at crystallographic ab plane. Moreover, each sip anion acts as a pentadentate bridge, interconnecting two different types of layers to yield a novel three-dimensional framework.

  4. Hydrothermal synthesis of NiFe$_2$O$_4$ nano-particles: structural, morphological, optical, electrical and magnetic properties

    Indian Academy of Sciences (India)

    K CHANDRA BABU NAIDU; W MADHURI

    2017-04-01

    NiFe$_2$O$_4$ nano-crystallites with an average diameter of 8.9 nm are synthesized via hydrothermal method.The single-phase spinel structure is confirmed from X-ray diffractograms. Morphology is analysed by transmissionand field emission scanning electron microscopes. High specific surface area of 55.7 m$^2$ g$^{−1}$ is obtained for nano-particles. The M–H loop and M–T curve behaviours are investigated by vibrating sample magnetometry.The optical band gap energy is estimated from the UV–visible spectrum. In addition, the frequency dependence of dielectric properties is investigated. Cole–Cole plots are drawn to study electrical conduction mechanism and thekind of relaxation—Debye or non-Debye type. Low a.c. conductivity and low magnetic losses are noticed at 5 MHz frequency, which are suitable for microwave device applications.

  5. Hydrothermal synthesis of xonotlite from carbide slag

    Institute of Scientific and Technical Information of China (English)

    Jianxin Cao; Fei Liu; Qian Lin; Yu Zhang

    2008-01-01

    Carbide slag was used as the calcareous materials for the first time to prepare xonotlite via dynamic hydrothermal synthesis.The effects of influential factors including different calcination temperatures,pretreatment methods of the carbide slag and process param-eters of hydrothermal synthesis on the microstructure and morphology of xonotlite were explored using XRD and SEM techniques.The results indicate that the carbide slag after proper calcination could be used to prepare pure xonotlite;and different calcination tern-peratures have little effect on the crystallinity of synthesized xonotlitc,but have great impact on the morphology of secondary particles.The different pretreatment methods of the carbide slag pose great impact on the crystallinity and morphology of secondary particles of xonotlite.Xonotlite was also synthesized from pure CaO under the salne experimental conditions as that prepared from calcined carbide slag for comparison.Little amount of impurities in carbide slag has no effect on the mechanism of hydrothermal synthesizing xonotlite from carbide slag.

  6. The hydrothermal synthesis of tetragonal tungsten bronze-based catalysts for the selective oxidation of hydrocarbons.

    Science.gov (United States)

    Botella, Pablo; Solsona, Benjamín; García-González, Ester; González-Calbet, José M; López Nieto, José M

    2007-12-21

    Mixed metal oxides with tetragonal tungsten bronze (TTB) structure, showing high activity and selectivity for the gas phase partial oxidation of olefins, have been prepared by hydrothermal synthesis from Keggin-type heteropolyacids.

  7. Hydrothermal synthesis of pyrochlores and their characterization

    Science.gov (United States)

    Redkin, Alexander F.; Ionov, Andrey M.; Kotova, Nataliya P.

    2013-10-01

    Pyrochlores, microlites, and U-betafites of pyrochlore group minerals were obtained from mixing experiments of the corresponding oxides and fluorides by hydrothermal synthesis at T = 800 °C and P = 200 MPa in the solution of 1.0 M NaF. The presence of U4+ in pyrochlore does not affect the cell parameter, which for the phases of pyrochlore-microlite series is 10.42 ± 0.01 Å. In a system with an excess of UO2, pyrochlores and microlites, containing uranium up to 0.2-0.3 atoms per formula unit (apfu), are formed. In the uranium-free system of betafites composition, perovskites and Ti-bearing pyrochlores are formed. U-pyrochlores of betafite series, containing 2Ti = Nb + Ta in moles, have cubic cell parameters of 10.26 ± 0.02 Å and U4+ isomorphic capacity of 0.4-0.5 apfu. In the pyrochlore structure, U4+ may substitute for Ca2+ and Na+ cations in the eightfold site. In pyrochlores of pyrochlore-microlite series, Ca2+ is replaced by U4+, while in pyrochlores of betafite series, U4+ replaces Na+. Phases with pyrochlore structure, containing U5+ and U6+ in the sixfold site, usually occupied by Nb5+, Ta5+, and Ti4+, are formed under oxidizing conditions (Cu-Cu2O buffer). They are characterized by low content of Nb5+, Ta5+ (<0.1 apfu), and anomalous behavior of the crystal lattice (compression, instead of expansion). Under natural conditions, the formation of pyrochlores containing a significant amount of U5+ and U6+ is unlikely.

  8. Hydrothermal Synthesis and Crystal Structure of a One-dimensional Copper(Ⅱ) Complex%Hydrothermal Synthesis and Crystal Structure of a One-dimensional Copper(Ⅱ) Complex

    Institute of Scientific and Technical Information of China (English)

    LI Xiu-Mei; WANG Qing-Wei; LIU Bo

    2012-01-01

    A metal-organic coordination polymer [Cu(cbba)2(bix)]n(Hcbba = 2-(4'-chlorine-benzoyl)-benzoic acid,bix = 1,4-bis(imidazol-1-ylmethyl)-benzene) 1 has been hydrothermally synthesized and characterized by elemental analysis,IR,TG,UV and single-crystal X-ray diffraction.Blue crystals crystallize in the monoclinic system,space group C2/c with a = 26.127(3),b = 10.6143(14),c = 14.5676(19) ,β = 111.289(2),V = 3764.3(8) 3,C42H30Cl2CuN4O6,Mr = 821.14,Dc = 1.449 g/cm3,F(000) = 1684,Z = 4,μ(MoKα) = 0.777 mm 1,the final R = 0.0528 and wR = 0.1200 for 2241 observed reflections(I 〉 2(I)).The structure of 1 exhibits a one-dimensional chain-like structure.

  9. Hydrothermal-hydrolysis synthesis and photocatalytic properties of nano-TiO2 with an adjustable crystalline structure.

    Science.gov (United States)

    Zhang, Jinghuan; Xiao, Xin; Nan, Junmin

    2010-04-15

    Tri-phase (anatase, rutile, and brookite), bi-phase (anatase and rutile), and mono-phase (rutile) TiO(2) nanomaterials with different morphologies were successively synthesized using a hydrothermal-hydrolysis method and adjusting the Ti(4+)/Ti(3+) molar ratio in a precursor solution. The properties of the fabricated nanomaterials were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), photocatalytic reaction, and other techniques. It has been shown that TiO(2) nanorods can be obtained by increasing the Ti(4+)/Ti(3+) molar ratio in a precursor solution from 1:0 to 0.3:0.7. TiO(2) nanoparticles are formed if the Ti(3+) fraction in the solution is further increased. The selective synthesis of TiO(2) nanomaterials is explained by a decrease in the reaction rate and by changes in acidity with increasing Ti(3+) content. The tri-phase nanorods and bi-phase nanoparticles synthesized with Ti(4+)/Ti(3+) molar ratios from 1:0 to 0.8:0.2 and 0.2:0.8 to 0:1, respectively, have a higher degradation ability with respect to methylene blue aqueous solutions under UV irradiation at ambient temperature compared to purely rutile TiO(2) nanorods synthesized with Ti(4+)/Ti(3+) molar ratios from 0.7:0.3 to 0.3:0.7. The high photocatalytic activity of the multi-phase TiO(2) samples is primarily attributed to their larger band gap and suppressed recombination of photo-generated electron-hole pairs.

  10. Hydrothermal synthesis of bismuth germanium oxide

    Energy Technology Data Exchange (ETDEWEB)

    Boyle, Timothy J.

    2016-12-13

    A method for the hydrothermal synthesis of bismuth germanium oxide comprises dissolving a bismuth precursor (e.g., bismuth nitrate pentahydrate) and a germanium precursor (e.g., germanium dioxide) in water and heating the aqueous solution to an elevated reaction temperature for a length of time sufficient to produce the eulytite phase of bismuth germanium oxide (E-BGO) with high yield. The E-BGO produced can be used as a scintillator material. For example, the air stability and radioluminescence response suggest that the E-BGO can be employed for medical applications.

  11. Hydrothermal Synthesis, Crystal Structure and Electrochemical Properties of Complex Mn2(phen)2(p-CBA)4(H2O)

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    One novel complex Mn2(phen)2(p-CBA)4(H2O) has been hydrothermally synthesized from p-chlorobenzoic acid (p-CBA), 1,10-phenanthroline (phen) and anhydrous man-ganese(Ⅱ) sulfate and then characterized. Crystal data for this complex: monoclinic, space group C2/c, with a = 2.3416(3), b = 1.5604(2), c =1.5605(2) nm, β = 121.048(2)° , V= 4.8849(12) nm3, Dc = 1.510 g/cm3, Mr = 555.26, Z = 8, μ = 0.798 mm-1, F(000) = 2256, GOOF = 1.032, the final R = 0.0393 and wR = 0.0816. The crystal structure shows that two neighboring manganese(Ⅱ) ions are linked together by two bridge-chelating p-chlorobenzoic groups and one bridging water molecule, forming a cage structure with the Mn-Mn bond distance of 0.3512 nm. Each manganese(Ⅱ) ion is coordinated by two nitrogen atoms of one 1,10-phenanthroline molecule and four oxygen atoms from three p-chlorobenzoic acid anions and one water molecule, giving a distorted octahedral coordination geometry. The cyclic voltammetric behavior of the complex was also investigated.

  12. Hydrothermal Synthesis, Crystal Structure and Spectral Characterization of a New Copper Isopolytungstate: [Cu(phen)3][W6O19

    Institute of Scientific and Technical Information of China (English)

    MENG Fan-Xia; LIU Kun; CHEN Ya-Guang

    2006-01-01

    An unusual inorganic-organic hybrid hexatungstate complex [Cu(phen)3][W6O19] 1(C36H24 CuN6O19W6, Mr= 2011.20) was hydrothermally synthesized and characterized by singlecrystal X-ray diffraction, IR spectrum, UV-VIS spectrum and elemental analyses. This compound crystallizes in the monoclinic system, space group C2/c with a = 19.1005(11), b = 11.2585(11), c =20.2867(15) (A),β= 102.177(2)°, V= 4264.4 (A)3, μ(MoKa) = 16.691 mm-1, Dc = 3.133 g/cm3, Z= 4,F(000) = 3628, the final R = 0.0338 and wR = 0.0798 for 4090 observed reflections with 1 > 2σ(Ⅰ).The result of structure determination shows that the crystal structure is constructed from [W6O19]2-cluster anions and [Cu(phen)3]2+ complex fragments, which are held together into a three-dimensional network through hydrogen-bonding interactions.

  13. Direct synthesis of Al-SBA-15 containing aluminosilicate species plugs in an acid-free medium and structural adjustment by hydrothermal post-treatment

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Lei [Key Laboratory of Fine Chemicals in Universities of Shandong, Shandong Polytechnic University, Daxue Road, Changqing District, Jinan 250353 (China); Xu, Yan [Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Laoshan District, Qingdao 266101 (China); Institute of Petrochemical Technology, Changzhou University, Gehu Road, Changzhou 213164 (China); Zhang, Na [Key Laboratory of Fine Chemicals in Universities of Shandong, Shandong Polytechnic University, Daxue Road, Changqing District, Jinan 250353 (China); Lin, Sen, E-mail: linsen@qibebt.ac.cn [Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Laoshan District, Qingdao 266101 (China); Li, Xiangping; Guo, Peng; Li, Xuebing [Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Laoshan District, Qingdao 266101 (China)

    2013-07-15

    A series of Al-SBA-15 with controllable aluminosilicate plug structures inside straight mesopores has been hydrothermally synthesized in a one-step synthesis in an environmentally friendly acid-free medium, using triblock copolymer Pluronic P123 as a structure-directing agent, water as solvent, tetraethyl orthosilicate (TEOS) and aluminum nitrate (Al(NO){sub 3}·9H{sub 2}O) as silica and aluminum sources, respectively. The effects of the P123/Si molar ratio in the initial solution and aging temperature on the structural properties of the resulting materials were investigated by powder X-ray diffraction (XRD), nitrogen adsorption–desorption at 77 K, transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetric (TG), FT-IR spectra and inductively coupled plasma (ICP) analyses. The nature of the Al species and the acidity of the resultant samples were studied by solid state {sup 27}Al MAS NMR and pyridine adsorption measurements. The specific surface area (935–755 m{sup 2}g{sup −1}), pore volume (1.03–0.56 cm{sup 3}g{sup −1}) and especially the concentration and distribution of open type mesopores (0–68% to the total pores) of the synthesized Al-SBA-15 can be controlled by a simple adjustment of the P123/Si molar ratio in the initial solution. Moreover, increasing the aging temperature higher than 363 K can remarkably decrease the formation of plug structures to obtain “open” form mesopores. The observation by TEM of alternate defined gray and white areas inside the mesopores gives the strong evidence of isolated microporous aluminosilicate plugs inside the channels. In addition, a moderate hydrothermal post-treatment can finely modify the mesostructures through the partial or complete dissolution of the aluminosilicate plugs. - Graphical abstract: The plugs-containing structures can be interpreted as the distribution of individual isolated plugs along the mesoporous channel. - Highlights: • Al-SBA-15 with controllable

  14. Hydrothermal Synthesis, Crystal Structure and Electrochemical Properties of Complex Zn(phen)(m-CBA)2(H2O)

    Institute of Scientific and Technical Information of China (English)

    LUO Bing-Chu; LI Chang-Hong; PENG Yun-Lin; KUANG Yun-Fei

    2007-01-01

    A novel complex Zn(phen)(m-CBA)2(H2O) with m-chlorobenzoic acid (m-CBA), 1,10-phenanthroline (phen) and zinc chloride has been hydrothermally synthesized and characterized. Crystal data for this complex: triclinic, space group P-1, a = 0.8361(5), b = 1.2455(7), c = 1.3107(7) nm, α = 115.637(8), β = 91.014(9), γ = 104.857(8)°, V = 1.1763(11) nm3, Dc = 1.623 g/cm3, Z = 2, F(000) = 584, GOOF = 1.078, the final R = 0.0453 and wR = 0.1192. Structure analysis shows that the zinc ion coordinates with two nitrogen atoms of one 1,10-phenanthroline molecule, three oxygen atoms from two m-chlorobenzoic acid molecules and one water molecule, giving a distorted square-pyramidal coordination geometry. The cyclic voltametric behavior of the complex was also investigated.

  15. Hydrothermal Synthesis, Crystal Structure and Thermal Analysis of a Dinuclear Complex Cd2(3,5-Dinitrobenzoate)4(pyridine)4

    Institute of Scientific and Technical Information of China (English)

    GUO Jin-Yu; ZHANG Tong-Lai; ZHANG Jian-Guo; LIU Yan-Hong; QIAO Xiao-Jing; YANG Li

    2006-01-01

    A dinuclear complex Cd2(dnba)4(pyridine)4 (dnba = 3,5-dinitrobenzoate) has been synthesized by hydrothermal method and characterized by X-ray single-crystal diffraction, elemen- tal analysis, FT-IR spectroscopy, DSC and TG-DTG techniques. The complex with empirical formula C48H32Cd2N12O24 (Mr = 692.83) crystallizes in monoclinic, space group P21/n with a = 12.0344(14), b = 10.5752(13), c = 21.578(3) (A), β = 104.150(2)o, V = 2662.8(6) (A)3, Z = 2, Dc = 1.728 g/cm3, μ(MoKα) = 0.897 mm-1, F(000) = 1384, S = 1.016 and (Δ/σ)max = 0.001. R = 0.0638 and wR = 0.0737 for all data; the final R = 0.0337 and wR = 0.0644. In this complex, four carboxylates are bidentate- or chelate-coordinated with the Cd(Ⅱ) centers to give the dinuclear structure. The other coordination positions of Cd(Ⅱ) are occupied by the lone pair electrons from N of four pyridines. Thermal analyses DSC and TG-DTG have been used to determine the thermal decomposition mechanism of the title complex.

  16. Hydrothermal Synthesis and Structural Characterization of NiO/SnO2 Composites and Hydrogen Sensing Properties

    Directory of Open Access Journals (Sweden)

    Chao Wei

    2015-01-01

    Full Text Available Pure SnO2 and NiO doped SnO2 nanostructures were successfully synthesized via a simple and environment-friendly hydrothermal method. X-ray powder diffraction (XRD, scanning electron microscopy (SEM, energy dispersive X-ray spectroscopy (EDS, and X-ray photoelectron spectra (XPS were used to investigate the crystalline structures, surface morphologies and microstructures, and element components and their valences of the as-synthesized samples. Furthermore, planar chemical gas sensors based on the synthesized pure SnO2 and NiO/SnO2 composites were fabricated and their sensing performances to hydrogen, an important fault characteristic gas dissolved in power transformer oil, were investigated in detail. Gas sensing experiments indicate that the NiO/SnO2 composites showed much higher gas response and lower working temperature than those of pure SnO2, which could be ascribed to the formation of p-n heterojunctions between p-type NiO and n-type SnO2. These results demonstrate that the as-synthesized NiO/SnO2 composites a promising hydrogen sensing material.

  17. Hydrothermal Synthesis, Crystal Structure and Thermal Properties of a Novel Samarium Complex with 1D Nano-chain Structure

    Institute of Scientific and Technical Information of China (English)

    LI Ya-Juan; LIANG Qing; SONG Hui-hua; JIA Mi-ying; SHI Shi-Kao; ZHANG Jian-jun

    2009-01-01

    @@ 1 Introduction The design and construction of metal-organic polymers has been a field of rapid growth in materials chemistry because of their intriguing topologies and potential applications as functional materials[1-6]. In this regard, every effort has been devoted to the deli-berate design and control of self-assembly infinite coordination networks via selecting the chemistry structures of ligands. Multidentate carboxylate ligands are widely adopted for construction of coordination frameworks due to their rich coordination modes[7-13].

  18. High Surface Area Ceria Nanoparticles via Hydrothermal Synthesis Experiment Design

    Directory of Open Access Journals (Sweden)

    Stanislav Kurajica

    2016-01-01

    Full Text Available Hydrothermal synthesis of CeO2 was optimized on two reactant concentrations and synthesis temperature and duration, in order to achieve material having the greatest specific surface area (SSA. Taguchi method of experimental design was employed in evaluation of the relative importance of synthesis parameters. CeO2 nanoparticles were characterized using X-ray diffraction, nitrogen adsorption-desorption isotherms, and scanning electron microscopy. Optimum conditions for obtaining particles with greater SSA were calculated according to Taguchi’s model “the-higher-the-better.” Synthesis temperature was found to be the only parameter significant for enabling nanoparticles with greater SSA. Mesoporous nanocrystalline ceria with SSA as great as 226 m2 g−1 was achieved, which is unprecedented for the hydrothermally synthesized ceria. The reason for this achievement was found in temperature dependence of the diffusion coefficient which, when low, favors nucleation yielding with fine particles, while when high it favors crystal growth and formation of one-dimensional structures. The occurrence of 1D-structure in sample exhibiting the smallest SSA was confirmed. Very fine crystallites with crystallite size as low as 5.9 nm have been obtained being roughly inverse proportional to SSA. Selected samples were tested as catalyst for soot oxidation. Catalyst morphology turned out to be decisive factor for catalytic activity.

  19. Conductivity dependence on synthesis parameters in hydrothermally synthesized ceria nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Anis-ur-Rehman, M., E-mail: marehman@comsats.edu.pk; Saleemi, A.S.; Abdullah, A.

    2013-12-05

    Highlights: •Facile synthesis of CeO{sub 2} with composite mediated hydrothermal method is done. •Synthesis parameters significantly effect on conduction. •Enhanced dc electrical conductivity (0.3386 S cm{sup −1}) is observed at 700 °C. •Better ac conductivity is observed 2.661 S cm{sup −1} at 700 °C for 3 MHz. •Potential material for electrolyte in fuel cells for higher efficiencies. -- Abstract: Nanoparticles of cerium oxide were synthesized by Composite Mediated Hydrothermal Approach (CMHA). The synthesis conditions were optimized to enhance the conduction properties and for narrow range of nanocrystallites. The synthesis parameters like hydrothermal treatment temperature (at 180 °C and 220 °C) and time (for 45 min, 70 min and 90 min) were optimized. The structural properties of the prepared ceria were examined by X-ray diffraction (XRD) data. Scherrer’s formula was used to calculate the crystallite sizes of average and most intense peak. Temperature dependent dc conductivity was measured in temperature range 200–700 °C and found to be increasing with the increase in measuring temperature and controlling the other synthesis conditions. The frequency dependent ac conductivity and dielectric properties were measured in frequency range 20 Hz–3 MHz at different temperatures. The ac conductivity increased (from 0.00091 to 2.661 S cm{sup −1}) with the increase in temperature (from 200 to 700 °C). Raman spectrum was observed for the different bands of cerium oxide and oxygen vacancies at 514 nm excitation laser line.

  20. Synthesis of three-dimensional rare-earth ions doped CNTs-GO-Fe{sub 3}O{sub 4} hybrid structures using one-pot hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Guo, E-mail: guogao@sjtu.edu.cn [Institute of Nano Biomedicine and Engineering, Department of Instrument Science and Technology, Key Laboratory for Thin Film and Microfabrication Technology of Ministry of Education, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Zhang, Qiang; Cheng, Xin-Bing [Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing 100084 (China); Sun, Rongjin [Institute of Nano Biomedicine and Engineering, Department of Instrument Science and Technology, Key Laboratory for Thin Film and Microfabrication Technology of Ministry of Education, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Shapter, Joseph G., E-mail: joe.shapter@flinders.edu.au [School of Chemical and Physical Sciences, Flinders University, Bedford Park, Adelaide 5042 (Australia); Yin, Ting [Institute of Nano Biomedicine and Engineering, Department of Instrument Science and Technology, Key Laboratory for Thin Film and Microfabrication Technology of Ministry of Education, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Cui, Daxiang, E-mail: dxcui@sjtu.edu.cn [Institute of Nano Biomedicine and Engineering, Department of Instrument Science and Technology, Key Laboratory for Thin Film and Microfabrication Technology of Ministry of Education, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2015-11-15

    Rechargeable lithium ion batteries (LIBs) are currently the dominant power source for all sorts of electronic devices due to their low cost and high energy density. The cycling stability of LIBs is significantly compromised due to the broad satellite peak for many anode materials. Herein, we develop a facile hydrothermal process for preparing rare-earth (Er, Tm) ions doped three-dimensional (3D) transition metal oxides/carbon hybrid nanocomposites, namely CNTs-GO-Fe{sub 3}O{sub 4}, CNTs-GO-Fe{sub 3}O{sub 4}-Er and CNTs-GO-Fe{sub 3}O{sub 4}-Tm. The GO sheets and CNTs are interlinked by ultrafine Fe{sub 3}O{sub 4} nanoparticles forming three-dimensional (3D) architectures. When evaluated as anode materials for LIBs, the CNTs-GO-Fe{sub 3}O{sub 4} hybrid composites have a bigger broad satellite peak. As for the CNTs-GO-Fe{sub 3}O{sub 4}-Er and CNTs-GO-Fe{sub 3}O{sub 4}-Tm hybrid composites, the broad satellite peak can be completely eliminated. When the current density changes from 5 C back to 0.1 C, the capacity of CNTs-GO-Fe{sub 3}O{sub 4}-Tm hybrid composites can recover to 1023.9 mAhg{sup −1}, indicating an acceptable rate capability. EIS tests show that the charge transfer resistance does not change significantly after 500 cycles, demonstrating that the cycling stability of CNTs-GO-Fe{sub 3}O{sub 4}-Tm hybrid composites are superior to CNTs-GO-Fe{sub 3}O{sub 4} and CNTs-GO-Fe{sub 3}O{sub 4}-Er hybrid structures. - Graphical abstract: One-pot hydrothermal method for synthesis of rare-earth ions doped CNTs-GO-Fe{sub 3}O{sub 4} hybrid structures as anode materials of LIBs have been reported. - Highlights: • We report the synthesis of rare-earth ions doped CNTs-GO-Fe{sub 3}O{sub 4} hybrid structures. • The hybrid structures can improve the cycling stability of lithium storage. • As for anode materials, the broad satellite peak can be completely eliminated. • When the rate return back to 0.1 C, the capacity can recover to 1023.9 mAhg{sup −1}. • After 500

  1. Hydrothermal synthesis and characterization of zirconia based catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Caillot, T., E-mail: Thierry.caillot@ircelyon.univ-lyon1.fr; Salama, Z.; Chanut, N.; Cadete Santos Aires, F.J.; Bennici, S.; Auroux, A.

    2013-07-15

    In this work, three equimolar mixed oxides ZrO{sub 2}/CeO{sub 2}, ZrO{sub 2}/TiO{sub 2}, ZrO{sub 2}/La{sub 2}O{sub 3} and a reference ZrO{sub 2} have been synthesized by hydrothermal method. The structural and surface properties of these materials have been fully characterized by X-ray diffraction, transmission electron microscopy, surface area measurement, chemical analysis, XPS, infrared spectroscopy after adsorption of pyridine and adsorption microcalorimetry of NH{sub 3} and SO{sub 2} probe molecules. All investigated mixed oxides are amphoteric and possess redox centers on their surface. Moreover, hydrothermal synthesis leads to catalysts with higher surface area and with better acid–base properties than classical coprecipitation method. Both Lewis and Brønsted acid sites are present on the surface of the mixed oxides. Compared to the other samples, the ZrO{sub 2}/TiO{sub 2} material appears to be the best candidate for further application in acid–base catalysis. - Graphical abstract: Mesoporous amorphous phase with a high surface area of titania zirconia mixed oxide obtained by hydrothermal preparation. - Highlights: • Three zirconia based catalysts and a reference were prepared by hydrothermal synthesis. • Mixed oxides present larger surface areas than the reference ZrO{sub 2}. • ZrO{sub 2}/TiO{sub 2} catalyst presents a mesoporous structure with high surface area. • ZrO{sub 2}/TiO{sub 2} catalyst presents simultaneously strong acidic and basic properties.

  2. The ethylene glycol template assisted hydrothermal synthesis of Co{sub 3}O{sub 4} nanowires; structural characterization and their application as glucose non-enzymatic sensor

    Energy Technology Data Exchange (ETDEWEB)

    Khun, K., E-mail: kimleang.khun@liu.se [Department of Science and Technology, Linköping University, SE-60174 Norrköping (Sweden); Ibupoto, Z.H. [Dr M.A. Kazi Institute of Chemistry, University of Sindh Jamshoro, Sindh Jamshoro (Pakistan); Liu, X. [Department of Physics, Chemistry and Biology, Linköping University, 58183 Linköping (Sweden); Beni, V. [Biosensors and Biolelectronics Centre, Department of Physics, Chemistry and Biology, Linköping University, 58183 Linköping (Sweden); Willander, M. [Department of Science and Technology, Linköping University, SE-60174 Norrköping (Sweden)

    2015-04-15

    Highlights: • Ethylene glycol assisted Co{sub 3}O{sub 4} nanowires were synthesized by hydrothermal method. • The grown Co{sub 3}O{sub 4} nanowires were used for sensitive non-enzymatic glucose sensor. • The proposed glucose sensor shows a wide linear range with fast response. • The Co{sub 3}O{sub 4} modified electrode is a highly specific enzyme-less glucose sensor. - Abstract: In the work reported herein the ethylene glycol template assisted hydrothermal synthesis, onto Au substrate, of thin and highly dense cobalt oxide (Co{sub 3}O{sub 4}) nanowires and their characterization and their application for non-enzymatic glucose sensing are reported. The structure and composition of Co{sub 3}O{sub 4} nanowires have been fully characterized using scanning electron microscopy, X-ray diffraction, high resolution transmission electron microscopy and X-ray photoelectron spectroscopy. The synthesized Co{sub 3}O{sub 4} nanowires resulted to have high purity and showed diameter of approximately 10 nm. The prepared Co{sub 3}O{sub 4} nanowires coated gold electrodes were applied to the non-enzymatic detection of glucose. The developed sensor showed high sensitivity (4.58 × 10{sup 1} μA mM{sup −1} cm{sup −2}), a wide linear range of concentration (1.00 × 10{sup −4}–1.2 × 10{sup 1} mM) and a detection limit of 2.65 × 10{sup −5} mM. The developed glucose sensor has also shown to be very stable and selective over interferents such as uric acid and ascorbic acid. Furthermore, the proposed fabrication process was shown to be highly reproducible response (over nine electrodes)

  3. Hydrothermal Synthesis and Crystal Structure of Manganese(Ⅱ) Coordination Polymer Assembled by 4-Sulfophthalate and 4,4'-Bipyridine

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ Introduction The rational design and synthesis of metal-directed supramolecular framework compounds have received much attention in coordination chemistry because of their potential applications in catalysis, molecular selection, nonlinear optics, ion exchange, and microelectronics[1-4].

  4. One-step hydrothermal synthesis of highly water-soluble secondary structural Fe3O4 nanoparticles

    Science.gov (United States)

    Yang, Xiwen; Jiang, Wei; Liu, Li; Chen, Binghua; Wu, Shixi; Sun, Danping; Li, Fengsheng

    2012-07-01

    Magnetite nanoparticles (MNPs) were prepared using the ferric acetylacetonate as the sole iron source in a facile hydrothermal route, while poly(acrylic acid) (PAA) was chosen as the stabilizer via one-step functionalized MNPs for better hydrophilic properties. The orthogonal was used in the paper for the experimental parameters optimization, including the solvent, the reaction time, the amount of stabilizer and the presynthesis. The obtained highly water dispersible MNPs with uniform size from about 50 to about 100 nm was individually composed of many monodisperse magnetite crystallites approximately 6 nm in size. And the MNPs show high magnetic properties, whose magnetite content was up to 76.76% and the saturation magnetization was 39.0 emu/g. Later the formation mechanism of MNPs was also discussed. Thus the MNPs proved to be very promising for biomedical applications.

  5. Single step synthesis of (a-Fe2O3) hematite films by hydrothermal electrochemical deposition

    OpenAIRE

    2015-01-01

    A single step electrodeposition of alpha-Fe2O3 films under hydrothermal conditions without post-annealing requirement is described. Primary attention is paid to understand the effects of synthesis conditions, such as temperature, precursor concentration, pH, and time on the structure and morphology of the films. Moreover, the photoelectrochemical properties of hematite films grown by hydrothermal-electrochemical deposition (HED) are also discussed. It is discovered that HED enables the produc...

  6. Single step synthesis of (a-Fe2O3) hematite films by hydrothermal electrochemical deposition

    OpenAIRE

    Yılmaz, Ceren; Ünal, Uğur

    2015-01-01

    A single step electrodeposition of alpha-Fe2O3 films under hydrothermal conditions without post-annealing requirement is described. Primary attention is paid to understand the effects of synthesis conditions, such as temperature, precursor concentration, pH, and time on the structure and morphology of the films. Moreover, the photoelectrochemical properties of hematite films grown by hydrothermal-electrochemical deposition (HED) are also discussed. It is discovered that HED enables the produc...

  7. Hydrothermal Synthesis of ZnO Structures Formed by High-Aspect-Ratio Nanowires for Acetone Detection.

    Science.gov (United States)

    Cao, Zhen; Wang, Yong; Li, Zhanguo; Yu, Naisen

    2016-12-01

    Snowflake-like ZnO structures originating from self-assembled nanowires were prepared by a low-temperature aqueous solution method. The as-grown hierarchical ZnO structures were investigated by X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM). The results showed that the snowflake-like ZnO structures were composed of high-aspect-ratio nanowires. Furthermore, gas-sensing properties to various testing gases of 10 and 50 ppm were measured, which confirms that the ZnO structures were of good selectivity and response to acetone and could serve for acetone sensor to detect low-concentration acetone.

  8. Structural study of the controlled hydrothermal synthesis of LiMn2O4 and LixMnyO2

    DEFF Research Database (Denmark)

    Christiansen, Troels Lindahl; Jensen, Kirsten Marie Ørnsbjerg; Shen, Yanbin

    LiMn2O4 , which crystallizes in the spinel structure, is of great interest as a cathode material for Li-ion batteries due to the high natural abundance of manganese, low toxicity, fast ionic diffusion and excellent battery capabilities. The structure is closely related to that of LixMnyO2......, with focus on the size of the nanoparticles. Using a two-phase model, the Rietveld refinements showed a bimodal size distribution for the LiMn2O4, which, to our knowledge, has previously only been determined using SEM. Using the structural Rieveld models for LixMnyO2 and LiMn2O4, a comparison of the two...

  9. Hydrothermal Synthesis,Crystal Structure and Properties of a Novel 2-D Grid-like CdⅡ Metal-organic Framework

    Institute of Scientific and Technical Information of China (English)

    LU Yan-Chun; LI Xiu-Rong; ZHANG Zhi-Hui; DU Miao

    2007-01-01

    A novel Cd(Ⅱ) coordination polymer,{[Cd3(tzo)2(suc)(H2O)6]·(suc)}n (Htzo = 1,2,4-triazole,H2suc = succinic acid),has been synthesized from the reaction of aqueous solution of niques,and structurally characterized by X-ray analysis and spectral techniques.To the best of our knowledge,among the few documented triazole-cadmium coordination polymers,this complex presents a novel configuration.The deprotonated 1,2,4-triazole is in tridentate and succinate in bis-chelate modes to link the Cd(Ⅱ) centers,generating a 2-D grid-like network topology.Thermogravimetric analysis results show that the framework architecture is a stable porous material.The fluorescent emission has also been discussed.

  10. Microwave-hydrothermal synthesis of perovskite bismuth ferrite nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Biasotto, G. [Laboratorio Interdisciplinar em Ceramica (LIEC), Departamento de Fisico-Quimica, Instituto de Quimica, UNESP, CEP 14800-900, Araraquara, SP (Brazil); Simoes, A.Z., E-mail: alezipo@yahoo.com [Universidade Estadual Paulista-Unesp, Faculdade de Engenharia de Guaratingueta, Av. Dr. Ariberto Pereira da Cunha, 333, Bairro Pedregulho, CEP 12516-410, Guaratingueta, SP (Brazil); Foschini, C.R.; Zaghete, M.A.; Varela, J.A.; Longo, E. [Laboratorio Interdisciplinar em Ceramica (LIEC), Departamento de Fisico-Quimica, Instituto de Quimica, UNESP, CEP 14800-900, Araraquara, SP (Brazil)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer BiFeO{sub 3} (BFO) nanoparticles were grown by hydrothermal microwave method (HTMW). Black-Right-Pointing-Pointer The soaking time is effective in improving phase formation. Black-Right-Pointing-Pointer Rietveld refinement reveals an orthorhombic structure. Black-Right-Pointing-Pointer The observed magnetism of the BFO crystallites is a consequence of particle size. Black-Right-Pointing-Pointer The HTMW is a genuine technique for low temperatures and short times of synthesis. -- Abstract: Hydrothermal microwave method (HTMW) was used to synthesize crystalline bismuth ferrite (BiFeO{sub 3}) nanoparticles (BFO) in the temperature of 180 Degree-Sign C with times ranging from 5 min to 1 h. BFO nanoparticles were characterized by means of X-ray analyses, FT-IR, Raman spectroscopy, TG-DTA and FE-SEM. X-ray diffraction results indicated that longer soaking time was benefit to refraining the formation of any impurity phases and growing BFO crystallites into almost single-phase perovskites. Typical FT-IR spectra for BFO nanoparticles presented well defined bands, indicating a substantial short-range order in the system. TG-DTA analyses confirmed the presence of lattice OH{sup -} groups, commonly found in materials obtained by HTMW process. Compared with the conventional solid-state reaction process, submicron BFO crystallites with better homogeneity could be produced at the temperature as low as 180 Degree-Sign C. These results show that the HTMW synthesis route is rapid, cost effective, and could be used as an alternative to obtain BFO nanoparticles in the temperature of 180 Degree-Sign C for 1 h.

  11. Microwave-hydrothermal synthesis of barium strontium titanate nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Simoes, A.Z., E-mail: alezipo@yahoo.co [Universidade Federal de Itajuba- Unifei - Campus Itabira, Rua Sao Paulo, 377, Bairro, Amazonas, CEP 35900-37, Itabira, MG (Brazil); Universidade Estadual Paulista- Unesp - Faculdade de Engenharia de Guaratingueta, Av. Dr. Ariberto Pereira da Cunha, 333, Bairro Pedregulho, CEP 12516-410 Guaratingueta, SP (Brazil); Moura, F.; Onofre, T.B. [Universidade Federal de Itajuba- Unifei - Campus Itabira, Rua Sao Paulo, 377, Bairro, Amazonas, CEP 35900-37, Itabira, MG (Brazil); Ramirez, M.A.; Varela, J.A.; Longo, E. [Laboratorio Interdisciplinar em Ceramica (LIEC), Departamento de Fisico-Quimica, Instituto de Quimica, UNESP, CEP 14800-900, Araraquara, SP (Brazil)

    2010-10-22

    Research highlights: {yields} Barium strontium titanate nanoparticles were obtained by the Hydrothemal microwave technique (HTMW) {yields} This is a genuine technique to obtain nanoparticles at low temperature and short times {yields} Barium strontium titanate free of carbonates with tetragonal structure was grown at 130 {sup o}C. - Abstract: Hydrothermal-microwave method (HTMW) was used to synthesize crystalline barium strontium titanate (Ba{sub 0.8}Sr{sub 0.2}TiO{sub 3}) nanoparticles (BST) in the temperature range of 100-130 {sup o}C. The crystallization of BST with tetragonal structure was reached at all the synthesis temperatures along with the formation of BaCO{sub 3} as a minor impurity at lower syntheses temperatures. Typical FT-IR spectra for tetragonal (BST) nanoparticles presented well defined bands, indicating a substantial short-range order in the system. TG-DTA analyses confirmed the presence of lattice OH- groups, commonly found in materials obtained by HTMW process. FE/SEM revealed that lower syntheses temperatures led to a morphology that consisted of uniform grains while higher syntheses temperature consisted of big grains isolated and embedded in a matrix of small grains. TEM has shown BST nanoparticles with diameters between 40 and 80 nm. These results show that the HTMW synthesis route is rapid, cost effective, and could serve as an alternative to obtain BST nanoparticles.

  12. Hydrothermal synthesis of zeolites from natural stellerite

    Institute of Scientific and Technical Information of China (English)

    李酽; 汪信; 董元彩; 朱俊武

    2002-01-01

    Y and P zeolites were synthesized hydrothermally from natural stellerite under different conditions and were characterized via XRD and FT-IR.The results show that the higher crystallinity of Y zeolite can be obtained in hydrothermal system with low alkalinity,low Ca2+/Na+ ratio,and high SiO2/Al2O3 ratio.The lattice space of the samples decreases as crystallization time increases.P Zeolite is prompted under condition of higher alkalinity and higher Ca2+/Na+ ratio.The intensity and number of bands in the range of 400 cm-1~900 cm-1 increases with reaction time.Bands at 680 cm-1,760 cm-1 and 860 cm-1 corresponding to Y zeolite appear during the crystallization stage.Most of these bands shift to higher wavenumbers when SiO2/Al2O3 ratio increases generally.In the hydrothermal system with reverse condition above,bands at 600 cm-1,420 cm-1~470 cm-1 hardly change as the crystallization time increases and the main crystal phase of P zeolite is obtained.

  13. A Novel Hydrothermal Synthesis of Single Crystalline PbS Nanorods and Their Characterization

    Institute of Scientific and Technical Information of China (English)

    Hongliang ZHU; Deren YANG; Hui ZHANG

    2005-01-01

    Lead sulfide (PbS) nanorods with a high aspect ratio were prepared by a novel thioglycolic acid assisted hydrothermal method. X-ray diffraction and transmission electron microscopy revealed that the product was rod-like PbS with cubic rock-salt structure. Further characterizations by selected area electron diffraction and high-resolution transmission electron microscopy showed that the PbS nanorods were single crystalline in nature. Furthermore, the mechanism and critical factors for the hydrothermal synthesis of the nanorods have been discussed.

  14. Synthesis of hydrogen cyanide under simulated hydrothermal conditions

    Science.gov (United States)

    Pinedo-González, Paulina

    Nitrogen is a fundamental element for life, where is present in structural (e.g., proteins), catalytic (e.g., enzymes and ribozymes), energy transfer (e.g., ATP) and information storage (RNA and DNA) biomolecules. Atmospheric and planetary models suggest that nitrogen was abundant in the early atmospheres of Earth as dinitrogen (N2 ), an inert gas under normal atmospheric conditions. To be available for prebiotic synthesis it must be converted into hydrogen cyanide (HCN), ammonia (NH3 ) and/or nitric oxide (NO), in a process referred to as nitrogen fixation. Due to the strength of the triple bond in N2 , nitrogen fixation, while thermodynamically favored is kinetically restricted. In a reducing atmosphere dominated by CH4 -N2 , thunderstorm lightning efficiently produces HCN and NH3 (Stribling and Miller, 1987). Nevertheless, photochemical and geochemical constraints strongly suggest that the early atmosphere was weakly reducing, dominated by CO2 and N2 with traces of CH4 , CO, and H2 (Kasting, 1993). Under these conditions, HCN is no longer synthesized in the lightning channel and instead NO is formed (Navarro-Gonźlez, et al., 2001). In volcanic plumes, where magmatic gases a were more reducing than in the atmosphere, NO can also be formed by the lava heat (Mather et al., 2004) or volcanic lightning (Navarro-Gonźlez et al., 1998). Surprisingly, dinitrogen can be a reduced to NH3 in hydrothermal systems (Brandes et al., 1998), but the formation of HCN and its derivates were not investigated. The present work explores the possibility of the formation of HCN as well as other nitrile derivatives catalyzed by mineral surfaces in hydrothermal vents. To simulate a hydrothermal atmosphere, the experiments were carried out in a stainless steel Parr R minireactor with a 0.1 M NH4 HCO3 solution (200 ml) with or without a mineral surface exposed at 1 bar at temperatures ranging from 100 to 375° C. Different mineral matrices are been investigated. Our preliminary results

  15. Alkaline earth metal-based metal-organic framework: hydrothermal synthesis, X-ray structure and heterogeneously catalyzed Claisen-Schmidt reaction.

    Science.gov (United States)

    Saha, Debraj; Maity, Tanmoy; Koner, Subratanath

    2014-09-14

    Two alkaline earth metal-based carboxylate systems, [Mg(HL)(H2O)2]n (1) and [Ca(H2L)2]n (2) (H3L = chelidamic acid) have been hydrothermally synthesized, and characterized by single-crystal X-ray diffraction, IR, elemental analysis, and thermo-gravimetric analysis. Compound 1 has a 2D structure incorporating two water molecules. The dehydrated species, 1a, generated from 1 by removal of the coordinated water, has been characterized by thermo-gravimetric analysis, IR, elemental analysis and variable temperature powder X-ray diffraction. Both 1 and its dehydrated species 1a catalyze the Claisen-Schmidt reaction under heterogeneous conditions, but 1a is a more effective catalyst under environmentally friendly conditions. The catalyst can readily be recovered and reused in successive cycles without detectable loss of activity. Compound 2 has a 3D structure and is thermally stable up to 540 °C, but is inactive catalytically.

  16. Hydrothermal Synthesis and Structural Characterization of a Novel Organic-Inorganic Hybrid Compound {[Cu(2,2'-bpy)2]2-Mo8O26}

    Institute of Scientific and Technical Information of China (English)

    WANG,Yong-Hui(王永慧); CHEN,Li-Dong(陈立东); HU,Chang-Wen(胡长文); WANG,En-Bo(王恩波); JIA,Heng-Qing(贾恒庆); HU,Ning-Hai(胡宁海)

    2002-01-01

    A novel organic-inorganic hybrid compound { [ Cu (2, 2'-bpy)2 ]2Mo8O26} has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction.The compound crystallizes in the orthorhombic space group,Pna21, with a= 2.4164(5), b = 1.8281(4), c = 1.1877(2)nm, V=5.247(2)nm3, Z=4, andfinal R1=0.0331, wR2 =0.0727. The structure consists of discrete {[Cu(2,2'-bpy)2]2Mo8O26} clusters, constructed from a β-octamolybdate subunit [ Mo8O26]4- covalently bonded to two [ Cu ( 2, 2'-bpy )2]2+ coordination complex rations via bridging oxo groups. In addition, the spectroscopic properties and thermal behavior of this compound have been investigated by spectroscopic techniques (UV-vis, IR, Raman and EPR spectra) and TG analysis.

  17. Hydrothermal Synthesis and Crystal Structure of Zinc(Ⅱ) Dinicotinate Complex [Zn(nic)2(H2O)4](nic=nicotinic acid):A Three-dimensional Hydrogen-bond Network

    Institute of Scientific and Technical Information of China (English)

    MAO Hong-yan; ZHANG Zong-pei; ZHANG Hong-yun; XU Chen; WANG En-bo; WU Qing-an; ZHU Yu

    2004-01-01

    @@ Introduction Nicotinic acid and its transition-metal comple-xes have become increasingly important due to their potential applications as cosmetics or medicines with antitumor, antibacterial and antifungal activities, and the activity in the maintenance of normal glucose metabolism[1-3], etc. A major research effort has been made to generate such materials and to study their biological activity[4-9]. But few of the previous works have directed towards the structure investigation of these metal complexes[6-9]. So, in this report we aim at testing the effect of hydrothermal synthesis on the formation of the crystal structures of crystalline [Zn(nic)2(H2O)4 ](nic=nicotinic acid).

  18. Peptide synthesis under Enceladus hydrothermal condition

    Science.gov (United States)

    Fujishima, Kosuke; Takano, Yoshinori; Takai, Ken; Takahagi, Wataru; Adachi, Keito; Shibuya, Takazo; Tomita, Masaru

    2016-07-01

    Enceladus is one of the moons of Saturn, and it has been known to harbor interior ocean beneath the icy crust. The mass spectrometry data obtained by Cassini spacecraft indicates the presence of salty, and most likely alkaline ocean containing various organic compounds. While geochemical and other radiation related processes for in situ production of organics remain elusive, thermally unaltered carbonaceous chondrites, consisting the main body of Enceladus are known to be enriched with organic matters potentially including the building blocks of life (e.g., amino acids and amino acid precursors). Assuming that abiotic amino acids exist in the Enceladus alkaline seawater, we hypothesized that water-rock interaction may contribute to condensation of localized amino acids leading to peptide formation. In order to test this hypothesis, we have developed the Enceladus hydrothermal reactor based on the chemical constraints obtained through previous experimental and theoretical studies. We have added six different amino acids and introduced a thermal fluctuation system simulating the periodic tidal heating of the interior chondritic core. Total, eight sea water samples were obtained over the course of 147 days of experiment. While detection of peptide using Capillary Electrophoresis Time-of-Flight Mass Spectrometry (CE-TOF/MS) is still at the preliminary stage, so far pH monitoring and H2 and CO2 Gas Chromatography Mass Spectrometry (GC-MS) data clearly indicated the occurrence of serpentinization/carbonation reaction. Here, we discuss the interaction between aqueous alteration reactions and thermal cycling processes for the role of abiotic peptide formation under the Enceladus hydrothermal condition.

  19. Facile hydrothermal synthesis of alpha manganese sesquioxide ({alpha}-Mn{sub 2}O{sub 3}) nanodumb-bells: Structural, magnetic, optical and photocatalytic properties

    Energy Technology Data Exchange (ETDEWEB)

    Gnanam, S., E-mail: gnanam.nanoscience@gmail.com [Department of Physics, Presidency College, Chennai 600005, Tamilnadu (India); Rajendran, V. [Department of Physics, Presidency College, Chennai 600005, Tamilnadu (India)

    2013-02-15

    Highlights: Black-Right-Pointing-Pointer {alpha}-Mn{sub 2}O{sub 3} nanoparticles sizes of 35-42 nm have been prepared by hydrothermal process. Black-Right-Pointing-Pointer Shapes of {alpha}-Mn{sub 2}O{sub 3}: Dumb-bell, Cauliflower, spherical with rod, spherical with wires. Black-Right-Pointing-Pointer The strong UV emission can be attributed to high purity and perfect crystallinity. Black-Right-Pointing-Pointer Photocatalytic activity of {alpha}-Mn{sub 2}O{sub 3} was studied by degradation of Remazol red B dye. - Abstract: Nanometer scale cubic bixbyite {alpha}-Mn{sub 2}O{sub 3} has been synthesized by a facile hydrothermal method, at a temperature of 450 Degree-Sign C in the presence of various surfactants. The X-ray diffraction (XRD) analysis shows that the average crystallite size of the sample is {approx}35-42 nm. The shapes of the {alpha}-Mn{sub 2}O{sub 3} nanoparticles include: Dumb-bell-like (anionic surfactant), Cauliflower-like (nonionic surfactant), spherical with rods (cationic surfactant) and spherical with wires (surface modifier). The shapes of {alpha}-Mn{sub 2}O{sub 3} nanoparticles depend on the type of surfactant used in the synthesis. The magnetic property of the anionic surfactant assisted sample was primarily studied, using the vibrating sample magnetometer (VSM). The optical absorption spectra confirmed the effectiveness of the selected capping agents, as the anionic capped {alpha}-Mn{sub 2}O{sub 3} colloids absorbed at shorter wavelength than the other agents, indicating a much smaller crystallite size. The property of strong UV emissions may be attributed to the high purity and perfect crystallinity of the as-prepared {alpha}-Mn{sub 2}O{sub 3}. The surfactants-assisted catalyst was tested for its photocatalytic activity towards the photodegradation of the harmful organic dye Remazol Red B, using a multilamp photo reactor. Possible formation mechanisms have also been proposed for the as-synthesized anionic surfactant assisted samples.

  20. Synthesis, structural and optical properties of pure and rare-earth ion doped TiO{sub 2} nanowire arrays by a facile hydrothermal technique

    Energy Technology Data Exchange (ETDEWEB)

    Bandi, Vengala Rao; Raghavan, Chinnambedu Murugesan; Grandhe, Bhaskar kumar; Kim, Sang Su [Department of Physics, Changwon National University, Changwon 641-773 (Korea, Republic of); Jang, Kiwan, E-mail: kwjang@changwon.ac.kr [Department of Physics, Changwon National University, Changwon 641-773 (Korea, Republic of); Shin, Dong-Soo [Department of Chemistry, Changwon National University, Changwon 641-773 (Korea, Republic of); Yi, Soung-Soo [Department of Photonics, Silla University, Busan 617-736 (Korea, Republic of); Jeong, Jung-Hyun [Department of Physics, Pukyong National University, Busan 608-737 (Korea, Republic of)

    2013-11-29

    Single crystalline pure and rare-earth metal ions (Eu{sup 3+} and Ce{sup 3+}) doped TiO{sub 2} nanowire arrays were prepared on conductive fluorine doped indium tin oxide substrates by a facile hydrothermal method. Initially the conditions and parameters were optimized to prepare the high quality TiO{sub 2} nanowire arrays in the absence of organic additives. The average diameter and length of the TiO{sub 2} nanowire were found to be ∼ 30–50 nm and ∼ 0.5–1.5 μm, respectively. The formations of rutile phase structure in all the samples were confirmed by x-ray diffractometric analysis while the transmission electron microscopy confirms the single crystallinity and the maximum orientation of growth direction along [001] for the as-grown TiO{sub 2} nanowire. The optical properties of all the samples were analyzed using photoluminescence spectroscopy. The photocatalytic properties of the pure and doped TiO{sub 2} were investigated for the decomposition of organic toludine blue-O dye under ultraviolet irradiation. The result demonstrates that the Ce{sup 3+}: TiO{sub 2} decomposed almost 90% of the organic dye within 80 min. - Highlights: • Rare-earth (RE) doped TiO{sub 2} nanowire arrays were prepared by hydrothermal method • RE doping enhanced the growth rate of TiO{sub 2} nanowire arrays • The catalysts used to check their photocatalytic activity by toludine blue-O dye • RE doped TiO2 act as unprecedented photocatalyst for organic dye decomposition.

  1. Hydrothermal synthesis and structural studies of a new coordination polymer of lanthanum(Ⅲ) with benzene-1,2,4,5-tetracarboxylic acid and 4,4'-bipyridine

    Institute of Scientific and Technical Information of China (English)

    Masoumeh Tabatabaee; Mahboubeh A. Sharif; Fatemeh Vakili; Saina Saheli

    2009-01-01

    A new lanthanum complex formulated as { (bpyH2)[La(btc)(H2O)4(NO3)]·2H2O }n (1) (btcH4=benzene-1,2,4,5-tetracarboxylic acid; bpy=4,4'-bipyridine) was hydrothermally synthesized. The complex was characterized by FT-IR spectroscopy, elemental analysis and X-ray diffraction. X-ray crystal structural analysis revealed that the compound belonged to the monoclinic space group C2/c with cell parameters a= 1.42806(7) nm, b=1.10258(5) ran, c=-1.60333(8) nm and β=101.9400(10)°. The complex was polymeric with La<Ⅲ atoms linked by four O atoms from two carboxylate groups of one benzene-1,2,4,5-tetracarboxylate. The LaⅢ atom was ten coordinated in a distorted tetracapped trigonal prism. In the crystal structure, a wide range of noncovalent interactions consisting of hydrogen bonding (of the types of O-H…O, N-H…O and C-H…O) and ion pairing interactions connected the various components into a supramolecular structure.

  2. Hydrothermal Synthesis, Structure Characterization and Magnetic Studies of Perovskite-type Fluorides K2NaVF6 and (NH4)aVF6

    Institute of Scientific and Technical Information of China (English)

    HE Li-jie; ZHANG Dong; FENG Shou-hua; CHEN Gang; ZOU Bo

    2012-01-01

    Two perovskite-type fluorides K2NaVF6 and (NH4)3VF6 were synthesized under mild hydrothermal conditions.The structures of the compounds were determined by means of powder X-ray diffraction analysis.The Rietveld refinement indicates that K2NaVF6 has a cubic elpasolite-type structure and crystallizes in space group Fm-3m with lattice constant a=8.3180(2) nm.(NH4)3VF6 has a cubic cryolite-type structure and crystallizes in space group Fm-3m with lattice parameter a=9.090(1) nm.The compounds were further characterized by scanning electron microscopy(SEM),thermogravimetric(TG) and differential thermal analysis(DTA).The variable temperature magnetic susceptibility of these two compounds was characterized for the first time and the result shows that the magnetic ordering is related to the crystallographic features and isolated magnetic unit with the temperature decreasing.

  3. Metal-organic and supramolecular networks driven by 5-chloronicotinic acid: Hydrothermal self-assembly synthesis, structural diversity, luminescent and magnetic properties

    Science.gov (United States)

    Gao, Zhu-Qing; Li, Hong-Jin; Gu, Jin-Zhong; Zhang, Qing-Hua; Kirillov, Alexander M.

    2016-09-01

    Four new crystalline solids, namely [Co2(μ2-5-Clnic)2(μ3-5-Clnic)2(μ2-H2O)]n (1), [Co(5-Clnic)2(H2O)4]·2(5-ClnicH) (2), [Pb(μ2-5-Clnic)2(phen)]n (3), and [Cd(5-Clnic)2(phen)2]·3H2O (4) were generated by hydrothermal self-assembly methods from the corresponding metal(II) chlorides, 5-chloronicotinic acid (5-ClnicH) as a principal building block, and 1,10-phenanthroline (phen) as an ancillary ligand (optional). All the products 1-4 were characterized by IR spectroscopy, elemental analysis, thermogravimetric (TGA), powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction. Their structures range from an intricate 3D metal-organic network 1 with the 3,6T7 topology to a ladder-like 1D coordination polymer 3 with the 2C1 topology, whereas compounds 2 and 4 are the discrete 0D monomers. The structures of 2 and 4 are further extended (0D→2D or 0D→3D) by hydrogen bonds, generating supramolecular networks with the 3,8L18 and ins topologies, respectively. Synthetic aspects, structural features, thermal stability, magnetic (for 1) and luminescent (for 3 and 4) properties were also investigated and discussed.

  4. Hydrothermal synthesis and physicochemical properties of ruthenium(0) nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Dikhtiarenko, A., E-mail: dikhtiarenkoalla@uniovi.es [Departamento de Quimica Organica e Inorganica, Universidad de Oviedo - CINN, 33006 Oviedo (Spain); Khainakov, S.A.; Garcia, J.R.; Gimeno, J. [Departamento de Quimica Organica e Inorganica, Universidad de Oviedo - CINN, 33006 Oviedo (Spain); Pedro, I. de; Fernandez, J. Rodriguez [CITIMAC, Facultad de Ciencias, Universidad de Cantabria, 39005 Santander (Spain); Blanco, J.A. [Departamento de Fisica, Universidad de Oviedo, 33007 Oviedo (Spain)

    2012-09-25

    Highlights: Black-Right-Pointing-Pointer Ruthenium nanoparticles were synthesized by hydrothermal technique. Black-Right-Pointing-Pointer The average size of the nanoparticles are depend on the reducing agent used. Black-Right-Pointing-Pointer The magnetic response seems to be dominated by a paramagnetic contribution characteristic of the band electronic magnetism of the ruthenium(0) nanoparticles. - Abstract: The synthesis of ruthenium nanoparticles in hydrothermal conditions using mild reducing agents (succinic acid, ascorbic acid and sodium citrate) is reported. The shape of the nanoparticles depends on the type of the reducing agent, while the size is more influenced by the pH of the medium. The magnetic response seems to be dominated by a paramagnetic contribution characteristic of the band electronic magnetism of the nanoparticles.

  5. ZnIO3(OH): a new layered noncentrosymmetric polar iodate--hydrothermal synthesis, crystal structure, and second-harmonic generating (SHG) properties.

    Science.gov (United States)

    Lee, Dong Woo; Kim, Saet Byeol; Ok, Kang Min

    2012-07-21

    A new noncentrosymmetric polar iodate material, ZnIO(3)(OH), has been hydrothermally synthesized as crystals and pure powders by using ZnO (or Zn(CH(3)CO(2))(2)·2H(2)O), HIO(3), and water. Single crystal X-ray diffraction was used to determine the crystal structure of the reported material. ZnIO(3)(OH) exhibits a layered structure that is composed of ZnO(6) and IO(3) polyhedra. Powder nonlinear optical (NLO) properties measurements on ZnIO(3)(OH) using 1064 nm radiation indicate the material has a second-harmonic generating (SHG) efficiency of approximately 20 times that of α-SiO(2). Additional SHG measurements reveal that the material is not phase-matchable (type 1). Infrared spectroscopy, elemental analysis, and thermogravimetric analysis for the reported compound are also presented. Crystal data: ZnIO(3)(OH), monoclinic, space group Cc (no. 9) with a = 4.67670(10) Å, b = 11.2392(4) Å, c = 6.3308(2) Å, β = 90.019(2)°, and Z = 4.

  6. Hydrothermal Synthesis,Crystal Structure and Thermal Stability of a Supramolecular Lead(II) Complex with 4-Nitrobenzoic Acid and 1,10-Phenanthroline

    Institute of Scientific and Technical Information of China (English)

    徐相君; 吴向阳; 徐婉珍; 周威; 闫永胜

    2012-01-01

    A new complex [Pb(phen)2(4-NBA)]2·2(NO3)·H2O(phen = 1,10-phenanthroline,4-NBA = 4-nitrobenzoate) has been hydrothermally synthesized and structurally determined by single-crystal X-ray diffraction,elemental analyses and IR spectroscopy.The complex crystallizes in monoclinic,space group P21/c with a = 13.416(3),b = 14.065(3),c = 16.845(3)(A°) ,β = 110.55(3)o,V = 2976.5(10)(A°)^3,Z = 2,Dc = 1.796 g/cm^3,F(000) = 1564,GOOF = 0.962,the final R = 0.0686 and wR = 0.1746.The crystal structure shows that the lead ion is coordinated with two carboxylate O atoms from the 4-NBA anion,and four N atoms from two phen molecules,forming a slightly distorted pentagonalbipyramidal coordination geometry.It is further extended by various supramo-lecular interactions to form a three-dimensional supramolecular network.The TG analysis result shows that this complex begins decomposing at 30 ℃ and decompounding completely at 733 ℃.

  7. Hydrothermal Synthesis and Structure of a New Two- dimensional Zincophosphite:Zn2(HPO3)3(H2DACH (DACH = 1,2-diaminocyclohexane)

    Institute of Scientific and Technical Information of China (English)

    潘建新; 郑寿添; 杨国昱

    2004-01-01

    A new open-framework zincophosphite, Zn2(HPO3)3(H2DACH 1, was hydrothermally synthesized in the presence of 1,2-diaminocyclohexane (DACH) as structure-directing agent. Its structure was determined by single-crystal X-ray diffraction and further characterized by FTIR, elemental analysis, powder X-ray diffraction and thermogravimetric analysis. Crystal data for 1: Mr = 486.88, monoclinic, space group P21/c with a = 10.2287(11), b = 9.7624(11), c = 16.1686(18) A,β = 92.573(2), V = 1612.9(3) A3, Z = 4, Dc = 2.005 g/cm3, F(000) = 984, μ = 3.314 mm-1 and S = 1.152. The final R = 0.0473 and wR = 0.1121 for 2456 observed reflections with I > 2σ(I). The inorganic layer consisting of four- and eight-membered rings is constructed of alternating ZnO4 tetrahedra and HPO3 pseudo pyramids by sharing vertices. The organic template molecules reside in the interlayer region and interact with the inorganic network through H-bonds.

  8. Hydrothermal Synthesis and Structure of a Copper(II) Complex, [Cu(4,4'-bpy)(H2O)3]SO4·2H2O

    Institute of Scientific and Technical Information of China (English)

    林碧洲; 刘培德

    2003-01-01

    The title complex [Cu(4,4'-bpy)(H2O)3]SO4@2H2O (Mr = 405.86) was synthesized under hydrothermal conditions and its crystal structure has been determined by X-ray diffraction. It crystallizes in the hexagonal system, space group P61 with a = 11.1870(4), c = 21.578(1)(A°), V = 2338.6(2)(A°)3, Dc = 1.729 g/cm3, Z = 6, ((MoKα) = 1.583 mm-1 and F(000) = 1254. The final R and wR are 0.0253 and 0.0416 for 1458 observed reflections with I≥2((I), respectively. It was revealed that the square pyramidal Cu(II) sites are linked through 4,4'-bipyridine groups, forming infinite one-dimensional chains, with the sulfate anions and lattice water molecules occupying the inter-chain positions. During the electrostatic interactions, there exist O...O hydrogen bonds and π-πstacking interactions between the parallel aromatic bipy rings in the structure.

  9. Energetics of Amino Acid Synthesis in Alkaline Hydrothermal Environments

    Science.gov (United States)

    Kitadai, Norio

    2015-12-01

    Alkaline hydrothermal systems have received considerable attention as candidates for the origin and evolution of life on the primitive Earth. Nevertheless, sufficient information has not yet been obtained for the thermodynamic properties of amino acids, which are necessary components for life, at high temperatures and alkaline pH. These properties were estimated using experimental high-temperature volume and heat capacity data reported in the literature for several amino acids, together with correlation algorithms and the revised Helgeson-Kirkham-Flowers (HKF) equations of state. This approach enabled determination of a complete set of the standard molal thermodynamic data and the revised HKF parameters for the 20 protein amino acids in their zwitterionic and ionization states. The obtained dataset was then used to evaluate the energetics of amino acid syntheses from simple inorganic precursors (CO2, H2, NH3 and H2S) in a simulated alkaline hydrothermal system on the Hadean Earth. Results show that mixing between CO2-rich seawater and the H2-rich hydrothermal fluid can produce energetically favorable conditions for amino acid syntheses, particularly in the lower-temperature region of such systems. Together with data related to the pH and temperature dependences of the energetics of amino acid polymerizations presented in earlier reports, these results suggest the following. Hadean alkaline hydrothermal settings, where steep pH and temperature gradients may have existed between cool, slightly acidic Hadean ocean water and hot, alkaline hydrothermal fluids at the vent-ocean interface, may be energetically the most suitable environment for the synthesis and polymerization of amino acids.

  10. Hydrothermal synthesis of nanostructured graphene/polyaniline composites as high-capacitance electrode materials for supercapacitors

    Science.gov (United States)

    Wang, Ronghua; Han, Meng; Zhao, Qiannan; Ren, Zonglin; Guo, Xiaolong; Xu, Chaohe; Hu, Ning; Lu, Li

    2017-03-01

    As known to all, hydrothermal synthesis is a powerful technique for preparing inorganic and organic materials or composites with different architectures. In this reports, by controlling hydrothermal conditions, nanostructured polyaniline (PANi) in different morphologies were composited with graphene sheets (GNS) and used as electrode materials of supercapacitors. Specifically, ultrathin PANi layers with total thickness of 10-20 nm are uniformly composited with GNS by a two-step hydrothermal-assistant chemical oxidation polymerization process; while PANi nanofibers with diameter of 50~100 nm are obtained by a one-step direct hydrothermal process. Benefitting from the ultrathin layer and porous structure, the sheet-like GNS/PANi composites can deliver specific capacitances of 532.3 to 304.9 F/g at scan rates of 2 to 50 mV/s. And also, this active material showed very good stability with capacitance retention as high as ~99.6% at scan rate of 50 mV/s, indicating a great potential for using in supercapacitors. Furthermore, the effects of hydrothermal temperatures on the electrochemical performances were systematically studied and discussed.

  11. Hydrothermal synthesis of nanostructured graphene/polyaniline composites as high-capacitance electrode materials for supercapacitors

    Science.gov (United States)

    Wang, Ronghua; Han, Meng; Zhao, Qiannan; Ren, Zonglin; Guo, Xiaolong; Xu, Chaohe; Hu, Ning; Lu, Li

    2017-01-01

    As known to all, hydrothermal synthesis is a powerful technique for preparing inorganic and organic materials or composites with different architectures. In this reports, by controlling hydrothermal conditions, nanostructured polyaniline (PANi) in different morphologies were composited with graphene sheets (GNS) and used as electrode materials of supercapacitors. Specifically, ultrathin PANi layers with total thickness of 10–20 nm are uniformly composited with GNS by a two-step hydrothermal-assistant chemical oxidation polymerization process; while PANi nanofibers with diameter of 50~100 nm are obtained by a one-step direct hydrothermal process. Benefitting from the ultrathin layer and porous structure, the sheet-like GNS/PANi composites can deliver specific capacitances of 532.3 to 304.9 F/g at scan rates of 2 to 50 mV/s. And also, this active material showed very good stability with capacitance retention as high as ~99.6% at scan rate of 50 mV/s, indicating a great potential for using in supercapacitors. Furthermore, the effects of hydrothermal temperatures on the electrochemical performances were systematically studied and discussed. PMID:28291246

  12. Controlling of morphology of Ni/Al-LDHs using microemulsionmediated hydrothermal synthesis

    Indian Academy of Sciences (India)

    Yun Zhao; Fenfei Xiao; Qingze Jiao

    2008-11-01

    A quaternary microemulsion, cetyltrimethylammonium bromide (CTAB)/water/-hexane/-hexanol, was selected for the synthesis of Ni/Al-layered double hydroxides (LDHs). Ni/Al-LDHs with nanowire-, spherical-, rod- and tube-like morphologies were prepared via the microemulsion-mediated hydrothermal synthesis. The CTAB concentration played an important role in determining the morphology of Ni/Al-LDHs. The structure, composition and morphology of the obtained Ni/Al-LDH nanostructures were investigated by X-ray diffraction, inductively coupled plasma emission spectroscopy, infrared spectrometer and transmission electron microscopy. A possible formation mechanism of Ni/Al-LDH nanostructures is proposed.

  13. Metal-organic and supramolecular networks driven by 5-chloronicotinic acid: Hydrothermal self-assembly synthesis, structural diversity, luminescent and magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Zhu-Qing, E-mail: zqgao2008@163.com [School of Chemical and Biological Engineering, Taiyuan University of Science and Technology, Taiyuan 030021 (China); Li, Hong-Jin [School of Chemical and Biological Engineering, Taiyuan University of Science and Technology, Taiyuan 030021 (China); Gu, Jin-Zhong, E-mail: gujzh@lzu.edu.cn [College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China); Zhang, Qing-Hua [School of Chemical and Biological Engineering, Taiyuan University of Science and Technology, Taiyuan 030021 (China); Kirillov, Alexander M. [Centro de Química Estrutural, Complexo I, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049–001 Lisbon (Portugal)

    2016-09-15

    Four new crystalline solids, namely [Co{sub 2}(µ{sub 2}-5-Clnic){sub 2}(µ{sub 3}-5-Clnic){sub 2}(µ{sub 2}-H{sub 2}O)]{sub n} (1), [Co(5-Clnic){sub 2}(H{sub 2}O){sub 4}]·2(5-ClnicH) (2), [Pb(µ{sub 2}-5-Clnic){sub 2}(phen)]{sub n} (3), and [Cd(5-Clnic){sub 2}(phen){sub 2}]·3H{sub 2}O (4) were generated by hydrothermal self-assembly methods from the corresponding metal(II) chlorides, 5-chloronicotinic acid (5-ClnicH) as a principal building block, and 1,10-phenanthroline (phen) as an ancillary ligand (optional). All the products 1–4 were characterized by IR spectroscopy, elemental analysis, thermogravimetric (TGA), powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction. Their structures range from an intricate 3D metal-organic network 1 with the 3,6T7 topology to a ladder-like 1D coordination polymer 3 with the 2C1 topology, whereas compounds 2 and 4 are the discrete 0D monomers. The structures of 2 and 4 are further extended (0D→2D or 0D→3D) by hydrogen bonds, generating supramolecular networks with the 3,8L18 and ins topologies, respectively. Synthetic aspects, structural features, thermal stability, magnetic (for 1) and luminescent (for 3 and 4) properties were also investigated and discussed. - Graphical abstract: A new series of crystalline solids was self-assembled and fully characterized; their structural, topological, luminescent and magnetic features were investigated. Display Omitted.

  14. Hydrothermal Synthesis and Structural Characterization of Two Zinc Coordination Polymers of 1,2-Di(4-pyridyl)ethylene and Benzenedicarboxylate

    Institute of Scientific and Technical Information of China (English)

    LIU,Dong; LI,Hong-Xi; CHEN,Yang; ZHANG,Yong; LANG,Jian-Ping

    2008-01-01

    Hydrothermal reactions of Zn(NO3)2·6H2O with 1,2-di(4-pyridyl)ethylene (dpe) and 1,4-benzenedicarboxylate (1,4-BDC) or 1,3-benzenedicarboxylate (1,3-BDC) in water gave rise to two new metal-organic coordination poly-mers, [Zn(1,4-BDC)(dpe)]n (1) and [Zn4O(1,3-BDC)3(dpe)]n (2). Both compounds were characterized by elemental analysis and IR spectroscopy, and their structures were determined by single crystal X-ray diffraction. 1 displays a rare 5-fold interpenetrating 66-diamondoid framework while 2 possesses an interlocked 3D network formed by in-clined interpenetration of 2D (4,4) networks that are constructed by μ4-oxo tetrazinc Zn4O cores and the bridging dpe and 1,3-BDC ligands. Thermal and photoluminescent properties of 1 and 2 were also investigated.

  15. Hydrothermal Synthesis, Crystal Structure and Photoluminescent Property of a Zinc(II) Coordination Polymer Assembled by Phthalate and 4,4'-Bipyridine

    Institute of Scientific and Technical Information of China (English)

    LI Xiu-Mei; WANG Qing-Wei; CUI Yun-Cheng; LI Chuan-Bi; WANG Ren-Zhang; LIU Bo

    2006-01-01

    A metal-organic coordination polymer {[Zn(Pht)(4,4′-bipy)(H2O)2]·2H2O}n (Pht = phthalate, 4,4′-bipy = 4,4′-bipyridine) 1 has been hydrothermally synthesized and characterized by elemental analysis, IR, TG, fluorescence spectrum and single-crystal X-ray diffraction. Yellow crystals crystallize in the monoclinic system, space group P2/n, a = 7.6346(14), b = 11.316(2), c = 10.8133(19) (A), β = 92.444(3)o, V = 933.3(3)(A)3, C18H20N2O8Zn, Mr = 457.73, Dc = 1.629 g/cm3, F(000) = 472, Z = 2, μ(MoKα) = 1.367 mm-1, the final R = 0.0323 and wR = 0.0821 for 1859 observed reflections (I > 2σ(I)). The structure of 1 exhibits a two-dimensional bilayer framework formed by hydrogen bonding interactions. Furthermore, 1 shows yellow photoluminescent pro- perty at room temperature.

  16. Hydrothermal Synthesis and Structure Characterization of Compound Zn(Hpydc)2(H2O) (pydc=pyridine-2,5-dicarboxylate)①

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The hydrothermal reaction of ZnO, H3PO4(85%), (H2NCH2CH2)2NH and H2pydc results in the formation of a discrete mononuclear zinc(II) complex Zn(Hpydc)2(H2O). It crystallizes in monoclinic space group C2/c with a = 17.9947(8), b = 7.1875(3), c = 12.5895(4) (, ( = 110.802(2)o, V = 1522.14(10) (3, Z = 4, Mr = 415.61, (C14H10N2O9Zn), Dc = 1.814g/cm3, μ = 16.71cm-1, F(000) = 840, R = 0.0505, wR = 0.1144. Each zinc(II) is coordinated to two nitrogen and three oxygen atoms of which two nitrogen and two oxygen atoms are from two pydc ligands, and one oxygen atom from the coordinated water molecule to form an irregular polyhedral geometry. The complex is linked further into a three-dimensional structure through the weak interactions of hydrogen bonds between the two oxygen atoms. IR spectrum of the complex is also discussed.

  17. Microwave-assisted hydrothermal synthesis of lead zirconate fine powders

    Directory of Open Access Journals (Sweden)

    Apinpus Rujiwatra

    2011-01-01

    Full Text Available A rapid synthesis of lead zirconate fine powders by microwave-assisted hydrothermal technique is reported. The influences of type of lead precursor, concentration of potassium hydroxide mineraliser, applied microwave power and irradiation time are described. The synthesised powders were characterised by powder X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopic microanalysis and light scattering technique. The merits of the microwave application in reducing reaction time and improving particle mono-dispersion and size uniformity as well as the drawbacks, viz. low purity of the desired phase and increasing demand of mineraliser, are discussed in relation to conventional heating method.

  18. Hydrothermal chemistry, structures, and luminescence studies of alkali hafnium fluorides.

    Science.gov (United States)

    Underwood, Christopher C; McMillen, Colin D; Chen, Hongyu; Anker, Jeffery N; Kolis, Joseph W

    2013-01-07

    This paper describes the hydrothermal chemistry of alkali hafnium fluorides, including the synthesis and structural characterization of five new alkali hafnium fluorides. Two ternary alkali hafnium fluorides are described: Li(2)HfF(6) in space group P31m with a = 4.9748(7) Å and c = 4.6449(9) Å and Na(5)Hf(2)F(13) in space group C2/m with a = 11.627(2) Å, b = 5.5159(11) Å, and c = 8.4317(17) Å. Three new alkali hafnium oxyfluorides are also described: two fluoroelpasolites, K(3)HfOF(5) and (NH(4))(3)HfOF(5), in space group Fm3m with a = 8.9766(10) and 9.4144(11) Å, respectively, and K(2)Hf(3)OF(12) in space group R3m with a = 7.6486(11) Å and c = 28.802(6) Å. Infrared (IR) spectra were obtained for the title solids to confirm the structure solutions. Comparison of these materials was made based on their structures and synthesis conditions. The formation of these species in hydrothermal fluids appears to be dependent upon both the concentration of the alkali fluoride mineralizer solution and the reaction temperature. Both X-ray and visible fluorescence studies were conducted on compounds synthesized in this study and showed that fluorescence was affected by a variety of factors, such as alkali metal size, the presence/absence of oxygen in the compound, and the coordination environment of Hf(4+).

  19. Hydrothermal synthesis of magnetite particles with uncommon crystal facets

    Directory of Open Access Journals (Sweden)

    Junki Sato

    2014-09-01

    Full Text Available Hydrothermal synthesis of Fe3O4 (magnetite particles was carried out using organic compounds as morphology control agents to obtain magnetite crystals with uncommon facets. It was established that the morphology of Fe3O4 crystals obtained by hydrothermal treatment of an aqueous solution containing Fe2+ and organic compounds depended on the organic compound used. The shape of the Fe3O4 particles obtained when no additives were used was quasi-octahedral. In contrast, the addition of picolinic acid, citric acid or pyridine resulted in the formation of polyhedral crystals, indicating the presence of not only {1 1 1}, {1 0 0} and {1 1 0} facets but also high-index facets including at least {3 1 1} and {3 3 1}. When citric acid was used as an additive, octahedral crystals with {1 1 1} facets also appeared, and their size decreased as the amount of citric acid was increased. Thus, control of Fe3O4 particle morphology was achieved by a simple hydrothermal treatment using additives.

  20. The synthesis of Ba2+ doped multiferroic BiFeO3 nanoparticles by using a hydrothermal approach in the presence of different surface activators and the investigation of structural and magnetic features

    Science.gov (United States)

    Mardani, Reza

    2017-05-01

    In this work, Bi1-x Ba x FeO3 nanoparticles were synthesized by a hydrothermal method in the presence of various surface activators, and different amounts of barium were inserted in a bismuth ferrite (x  =  0.1, 0.15, 0.2) structure instead of bismuth. The structural and magnetic properties, morphology, and size of the synthesized nanoparticles were investigated by XRD, FT-IR, FE-SEM, TEM, DLS and VSM. The XRD analysis results reveal that the synthetic nanoparticles have a single phase. A phase shift from a rhombohedral structure to a tetragonal structure occurs due to the enhanced barium amount in the bismuth ferrite structure. The SEM analysis exhibits a uniform shape of the Bi0.85Ba0.15FeO3 particles and the image observed by TEM clarifies the size of the particles as 11 nm. Furthermore, the effect of the diverse surfaces of activators in the synthesis of Bi0.85Ba0.15FeO3 nanoparticles was studied, revealing that when sugar was used as a surfactant, the particle size reduced and the magnetic properties increased notably.

  1. Facile template-free hydrothermal synthesis and microstrain measurement of ZnO nanorods

    Indian Academy of Sciences (India)

    L Motevalizadeh; Z Heidary; M Ebrahimizadeh Abrishami

    2014-05-01

    ZnO nanorods were synthesized at low temperature by hydrothermally heating 0.1 M solution of ZnCl2 for 5, 10 and 15 h at a pH of 10. No template, seeded substrate, catalyst and autoclave were employed for the synthesis of ZnO nanorods. The effect of heating durations on the morphology and crystal orientation of the structure were investigated by using scanning electron microscopy and X-ray diffraction, respectively. SEM images showed that the flower-like structures were formed in 5 h hydrothermally-heated sample, whereas the hexagonal zinc oxide nanorods were perfectly fabricated with the increase in growth time. XRD patterns showed that the preferred orientation in nanorods could be controlled by hydrothermal treatment time. The crystallite size and microstrain were analysed by Williamson–Hall and Halder–Wagner methods. These results revealed the presence of defects in ZnO nanorods. However, by increasing the hydrothermal treatment time, both defects in lattice and crystallite size are decreased.

  2. Hydrothermal synthesis of 3D porous architectures

    Institute of Scientific and Technical Information of China (English)

    XIAO Wanyan; GU Xiaojun; XUE Dongfeng

    2009-01-01

    A novel porous lanthanide-organic coordination polymer, [Nd(H2O)(HnicO)(TP)]·2H2O (1) (H2nicO=2-hydroxynieotinic acid, TP= terephthalate), was prepared under hydrothermai condition and characterized by single-crystal X-ray diffraction, thermogravimetrie analysis and infrared spectroscopy. Compound 1 exhibited a flexible coordination geometry of lanthanide ions, which possessed a three-dimensional (3D) open framework with one-dimensional (1D) channels containing lattice water molecules. This framework structure exhibited a high stability up to 330 ℃ after removing free water molecules. A homometallic supramolecular framework (Zn(HnicO)2(H2O)2 (2)) was obtained due to the competitive reaction between organic ligands, Nd3+ and Zn2+ ions. The results showed that on the basis of the soft-hard/acid-base principle the coordination selection between metal ions and organic ligands played an essential role in the smart construc-tion of lanthanide architectures.

  3. Hydrothermal Synthesis of Ni/Al Layered Double Hydroxide Nanorods

    OpenAIRE

    Yun Zhao; Fenfei Xiao; Qingze Jiao

    2011-01-01

    Ni/Al layered double hydroxide (LDH) nanorods were successfully synthesized by the hydrothermal reaction. The crystal structure of the products was characterized by X-ray diffraction (XRD). The morphology of the products was observed using transmission electron microscopy (TEM) and field emission scanning electron microscopy (SEM). The influences of reaction time and pH value on the morphology of the Ni/Al LDHs were investigated. The result showed that the well-crystallized nanorods of Ni/Al ...

  4. HYDROTHERMAL SYNTHESIS OF NANO-METER MICROPOROUS ZINC FERRITE

    Institute of Scientific and Technical Information of China (English)

    Xiaoling Hu; Ping Guan; Xin Yan

    2004-01-01

    Nano-meter microporous zinc ferrite was prepared by a hydrothermal method, using triethylamine as a template. Adsorption curves showed that the product had a microporous structure. The effects of precursor pH, reaction temperature and reaction time on the preparation were studied, yielding optimal conditions: pH=11,448 K, 360 min. The morphology of zinc ferrite as observed by TEM, showed that zinc ferrite was well-crystallized and well-dispersed with little conglomeration.

  5. Pathways for abiotic organic synthesis at submarine hydrothermal fields.

    Science.gov (United States)

    McDermott, Jill M; Seewald, Jeffrey S; German, Christopher R; Sylva, Sean P

    2015-06-23

    Arguments for an abiotic origin of low-molecular weight organic compounds in deep-sea hot springs are compelling owing to implications for the sustenance of deep biosphere microbial communities and their potential role in the origin of life. Theory predicts that warm H2-rich fluids, like those emanating from serpentinizing hydrothermal systems, create a favorable thermodynamic drive for the abiotic generation of organic compounds from inorganic precursors. Here, we constrain two distinct reaction pathways for abiotic organic synthesis in the natural environment at the Von Damm hydrothermal field and delineate spatially where inorganic carbon is converted into bioavailable reduced carbon. We reveal that carbon transformation reactions in a single system can progress over hours, days, and up to thousands of years. Previous studies have suggested that CH4 and higher hydrocarbons in ultramafic hydrothermal systems were dependent on H2 generation during active serpentinization. Rather, our results indicate that CH4 found in vent fluids is formed in H2-rich fluid inclusions, and higher n-alkanes may likely be derived from the same source. This finding implies that, in contrast with current paradigms, these compounds may form independently of actively circulating serpentinizing fluids in ultramafic-influenced systems. Conversely, widespread production of formate by ΣCO2 reduction at Von Damm occurs rapidly during shallow subsurface mixing of the same fluids, which may support anaerobic methanogenesis. Our finding of abiogenic formate in deep-sea hot springs has significant implications for microbial life strategies in the present-day deep biosphere as well as early life on Earth and beyond.

  6. Synthesis of potassium hexatitanate whiskers using hydrothermal method

    Institute of Scientific and Technical Information of China (English)

    WANG Ju; LI Chun; LIANG Bin; WANG Xiaoqing

    2009-01-01

    High quality potassium hexatitanate whiskers were hydrothermally synthesized in one step under moderate temperature and pressure condi-tions. Effects of the titanium source and reaction conditions on the hydrothermal reaction rate, product phase component, and morphology of whiskers were investigated. The results show that the reactivity of hydrated titania, anatase TiO2, and rutile TiO2 with KOH decreases in turn, and with hydrated titania as titanium source, it is difficult to obtain potassium hexatitanate whiskers with good morphology. In contrast, uni-form potassium hexatitanate whiskers with a length of 10-20 μm and a diameter of 200-700 nm were obtained using anatase TiO2 as titanium source. The investigation demonstrates that the initial KOH concentration, annealing temperature and time, molar ratio of K2O/TiO2, etc. sig-nificantly affect the morphology of the as-synthesized whiskers. The optimized synthesis condition is as follows: anatase as a titanium source; 10 wt.% KOH solution; annealing temperature and time of 300℃ and 5 h, respectively; K2O/TiO2 molar ratio orS, etc. A rhombic potassium hexatitanate was prepared under the optimum condition and the whisker grew along the [110] direction. The reaction mechanism was dis-cussed.

  7. Growth of "waist" ZnO twin rods through hydrothermal synthesis.

    Science.gov (United States)

    Tan, Lixia; Yu, Xianjin; Zhang, Lipeng; Yang, Ping

    2014-04-01

    The factors that govern the deposition and structure of "waist" ZnO twin rods from aqueous solution through hydrothermal synthesis were discussed in details. Pencil-like ZnO hexagonal twin rods were obtained in Zn(2+) + HMTA system on ITO glass substrates with ZnO buffer layer deposited in advance. As a contrast, a series of experiments were preceded with TBAB or on bare Cu sheet, Zn sheet, and Al sheet to research lattice-match influences on ZnO nucleation. A series of "waist" ZnO hexagonal twin rods were synthesized and the morphology of each "waist" was shown. The forming of different waists results from the different lattice-match effects between substrates and ZnO crystal. We demonstrated ZnO hexagonal twin rods synthesis on Cu, Al, Zn sheet by normal hydrothermal synthesis and revealed different forming schemes of these varying "waists" of the twin structures. On the basis of our research, not only some new ways of synthesizing ZnO twin rods were proposed but a new idea of applying metal to nano-devices used in piezoelectric area.

  8. The effects of Te on the performance of Mo-V catalysts prepared by hydrothermal synthesis

    Institute of Scientific and Technical Information of China (English)

    Hua Chang Jiang; Ling Zeng; Bin Long Yin

    2007-01-01

    Some Mo-V-Te-La catalysts with varied component were prepared by hydrothermal synthesis and dried with microwave method. The component of the catalyst were greatly affected the crystal structure and Raman spectrum. The phase in the catalysts was different when the Mo, V, and Te content varied. When the catalyst containing the same Mo, V content, due to the effect of dopant of Te element (V0.07 Mo0.93)5O14 became the main phase in the catalyst. The catalyst also showed good activity for the reaction of selective oxidation propane to acrolein and acrylic acid.

  9. Zinc(II) and lead(II) metal-organic networks driven by a multifunctional pyridine-carboxylate building block: Hydrothermal synthesis, structural and topological features, and luminescence properties

    Science.gov (United States)

    Yang, Ling; Li, Yu; You, Ao; Jiang, Juan; Zou, Xun-Zhong; Chen, Jin-Wei; Gu, Jin-Zhong; Kirillov, Alexander M.

    2016-09-01

    4-(5-Carboxypyridin-2-yl)isophthalic acid (H3L) was applied as a flexible, multifunctional N,O-building block for the hydrothermal self-assembly synthesis of two novel coordination compounds, namely 2D [Zn(μ3-HL)(H2O)]n·nH2O (1) and 3D [Pb2(μ5-HL)(μ6-HL)]n (2) coordination polymers (CPs). These compounds were obtained in aqueous medium from a mixture containing zinc(II) or lead(II) nitrate, H3L, and sodium hydroxide. The products were isolated as stable crystalline solids and were characterized by IR spectroscopy, elemental, thermogravimetric (TGA), powder (PXRD) and single-crystal X-ray diffraction analyses. Compound 1 possesses a 2D metal-organic layer with the fes topology, which is further extended into a 3D supramolecular framework via hydrogen bonds. In contrast, compound 2 features a very complex network structure, which was topologically classified as a binodal 5,6-connected net with the unique topology defined by the point symbol of (47.63)(49.66). Compounds 1 and 2 disclose an intense blue or green luminescent emission at room temperature.

  10. Stirring effect in hydrothermal synthesis of nano C-LiFePO4

    Science.gov (United States)

    Vediappan, K.; Guerfi, A.; Gariépy, V.; Demopoulos, G. P.; Hovington, P.; Trottier, J.; Mauger, A.; Julien, C. M.; Zaghib, K.

    2014-11-01

    C-LiFePO4 positive electrode materials were prepared by hydrothermal synthesis in which the solution was stirred with a rotation frequency varying from 50 to 1150 revolutions per minute (rpm), before carbon coating. The different synthesized cathode materials are discussed and compared in terms of structural, surface-morphological and electrochemical properties. The best C-LiFePO4 electrodes have been obtained using rotation frequencies in the range 280-360 rpm, in which case the capacity retention reaches ∼137 mAh g-1 at coulombic efficiency >99% at C/12, against 106 mAh g-1 in the absence of agitation. Better cycling stability at high current rates (1C) were also obtained. The improved performance of the C-LiFePO4 material obtained by controlled rotating agitation-hydrothermal solution synthesis is attributed to the production of less aggregated particles with high surface area and smaller concentrations of impurities. The controlled rotating agitation of the solution during the synthesis provides a scalable and eco-friendly way of producing better performing electrode particles for use in Li-ion batteries.

  11. Microwave-Assisted Hydrothermal Synthesis of Cellulose/Hydroxyapatite Nanocomposites

    Directory of Open Access Journals (Sweden)

    Lian-Hua Fu

    2016-09-01

    Full Text Available In this paper, we report a facile, rapid, and green strategy for the synthesis of cellulose/hydroxyapatite (HA nanocomposites using an inorganic phosphorus source (sodium dihydrogen phosphate dihydrate (NaH2PO4·2H2O, or organic phosphorus sources (adenosine 5′-triphosphate disodium salt (ATP, creatine phosphate disodium salt tetrahydrate (CP, or D-fructose 1,6-bisphosphate trisodium salt octahydrate (FBP through the microwave-assisted hydrothermal method. The effects of the phosphorus sources, heating time, and heating temperature on the phase, size, and morphology of the products were systematically investigated. The experimental results revealed that the phosphate sources played a critical role on the phase, size, and morphology of the minerals in the nanocomposites. For example, the pure HA was obtained by using NaH2PO4·2H2O as phosphorus source, while all the ATP, CP, and FBP led to the byproduct, calcite. The HA nanostructures with various morphologies (including nanorods, pseudo-cubic, pseudo-spherical, and nano-spherical particles were obtained by varying the phosphorus sources or adjusting the reaction parameters. In addition, this strategy is surfactant-free, avoiding the post-treatment procedure and cost for the surfactant removal from the product. We believe that this work can be a guidance for the green synthesis of cellulose/HA nanocomposites in the future.

  12. Hydrothermal synthesis, crystal structure and luminescence property of a three dimensional Sm(III) coordination polymer with 2,5-pyridinedicarboxylic acid

    Indian Academy of Sciences (India)

    Kranthi Kumar Gangu; Anima S Dadhich; Saratchandra Babu Mukkamala

    2015-12-01

    A novel three dimensional coordination polymer [Sm(2,5-pydc)(NO3)(H2O)]·(H2O) (2,5-pydc = 2,5-pyridine dicarboxylate) (1) had been synthesized hydrothermally and characterized by elemental analysis, FT-IR and single-crystal X-ray diffraction analysis. This coordination polymer crystallized in the monoclinic space group P2/n with cell parameters = 9.3610(4) Å, = 8.3498(3) Å, = 16.7159(8) Å, = 106.31(0)°, = 1253.98(184) Å3. Thermogravimetric analysis revealed that complex 1 is stable up to 400°C which on photoexcitation at 365 nm exhibited yellow emission at 583 nm.

  13. Hydrothermal synthesis and crystal structure of copper (Ⅱ)coordination polymer composed of helix-like chains:[Cu(NIPH)(bpy)

    Institute of Scientific and Technical Information of China (English)

    YE Junwei; ZHANG Ping; YE Kaiqi; YE Ling; YANG Guangdi; WANG Yue

    2006-01-01

    Hydrothermal reactions of Cu (Ⅱ) acetate, 2,2'-bipyridyl (bpy) with 5-nitroisophthalic acid (H2NIPH) resulted in a new coordination polymer [Cu(NIPH)(bpy)] 1. Single crystal X-ray diffraction experiment indicates that 1 possesses a single helixlike chains, of which Cu atoms are coordinated by NIPH ligands and bpy ligands. Compound 1 crystallizes in the space group P2(1)/c, a = 0.955(19) nm, b = 1.259(3) nm, c= 1.3737(3) nm, β= 95.13(3)°, V=1.6455(6) nm3 and Z = 4. The TGA analysis shows that 1 has no remarkable weight loss up to 284℃, as a result of its high thermal stability. Magnetic measurements indicate an antiferromagnetic behavior of compound 1.

  14. Hydrothermal synthesis of highly nitrogen-doped few-layer graphene via solid–gas reaction

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Xianqing, E-mail: lxq@gxu.edu.cn [College of Physics Science and Technology, Guangxi University, Nanning 530004 (China); Zhong, Jun [Jiangsu Key Laboratory for Carbon-Based Functional Material and Devices, Institute of Functional Nano and Soft Materials Laboratory (FUNSOM), Soochow University, Suzhou 215123 (China); Shi, Yalin; Guo, Jin; Huang, Guolong [College of Physics Science and Technology, Guangxi University, Nanning 530004 (China); Hong, Caihao; Zhao, Yidong [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

    2015-01-15

    Highlights: • A novel approach to synthesis of N-doped few-layer graphene has been developed. • The high doping levels of N in products are achieved. • XPS and XANES results reveal a thermal transformation of N bonding configurations. • The developed method is cost-effective and eco-friendly. - Abstract: Nitrogen-doped (N-doped) graphene sheets with high doping concentration were facilely synthesized through solid–gas reaction of graphene oxide (GO) with ammonia vapor in a self-designed hydrothermal system. The morphology, surface chemistry and electronic structure of N-doped graphene sheets were investigated by TEM, AFM, XRD, XPS, XANES and Raman characterizations. Upon hydrothermal treatment, up to 13.22 at% of nitrogen could be introduced into the crumpled few-layer graphene sheets. Both XPS and XANES analysis reveal that the reaction between oxygen functional groups in GO and ammonia vapor produces amide and amine species in hydrothermally treated GO (HTGO). Subsequent thermal annealing of the resultant HTGO introduces a gradual transformation of nitrogen bonding configurations in graphene sheets from amine N to pyridinic and graphitic N with the increase of annealing temperature. This study provides a simple but cost-effective and eco-friendly method to prepare N-doped graphene materials in large-scale for potential applications.

  15. Pyrophosphate synthesis in iron mineral films and membranes simulating prebiotic submarine hydrothermal precipitates

    Science.gov (United States)

    Barge, Laura M.; Doloboff, Ivria J.; Russell, Michael J.; VanderVelde, David; White, Lauren M.; Stucky, Galen D.; Baum, Marc M.; Zeytounian, John; Kidd, Richard; Kanik, Isik

    2014-03-01

    Cells use three main ways of generating energy currency to drive metabolism: (i) conversion of adenosine diphosphate (ADP) to adenosine triphosphate (ATP) by the proton motive force through the rotor-stator ATP synthase; (ii) the synthesis of inorganic phosphate˜phosphate bonds via proton (or sodium) pyrophosphate synthase; or (iii) substrate-level phosphorylation through the direct donation from an active phosphoryl donor. A mechanism to produce a pyrophosphate bond as “energy currency” in prebiotic systems is one of the most important considerations for origin of life research. Baltscheffsky (1996) suggests that inorganic pyrophosphate (PO74-; PPi) may have preceded ATP/ADP as an energy storage molecule in earliest life, produced by an H+ pyrophosphatase. Here we test the hypothesis that PPi could be synthesized in inorganic precipitates simulating hydrothermal chimney structures transected by thermal and/or ionic gradients. Appreciable yields of PPi were obtained via substrate phosphorylation by acetyl phosphate within the iron sulfide/silicate precipitates at temperatures expected for an alkaline hydrothermal system. The formation of PPi only occurred in the solid phase, i.e. when both Pi and the phosphoryl donor were precipitated with Fe-sulfides or Fe-silicates. The amount of Ac-Pi incorporated into the precipitate was a significant factor in the amount of PPi that could form, and phosphate species were more effectively incorporated into the precipitate at higher temperatures (⩾50 to >85 °C). Thus, we expect that the hydrothermal precipitate would be more enriched in phosphate (and especially, Ac-Pi) near the inner margins of a hydrothermal mound where PPi formation would be at a maximum. Iron sulfide and iron silicate precipitates effectively stabilized Ac-Pi and PPi against hydrolysis (relative to hydrolysis in aqueous solution). Thus it is plausible that PPi could accumulate as an energy currency up to useful concentrations for early life in a

  16. Hydrothermal Synthesis and Crystal Structure of a Bivanadyl Capped Keggin Polyoxometalate [Zn(2,2'-bpy)2(H2O)]2[HPMo12O40(VO)2

    Institute of Scientific and Technical Information of China (English)

    吕秀清; 陈建新; 兰婷燕; 黄远标

    2005-01-01

    A hydrothermal reaction of zinc acetate with molybdenum trioxide, vanadium pentoxide, phosphorus pentoxide and 2,2'-bpy (2,2'-bipyridine) led to the title compound [Zn(2,2'- bpy)2(H2O)]2[HPMo12O4o(VO)2] 1. Single-crystal X-ray diffraction revealed that 1 (C40H36- N8O44PV2Zn2Mo12) crystallizes in the triclinic system, space group P1 with a = 11.881(2), b = 12.468(2), c = 12.622(2) (A), a = 71.333(8), β = 74.485(4), γ = 86.896(5)°, V = 1705.8(4) (A)3, Mr = 2747.64, Z = 1, Dc = 2.675 g/cm3, μ = 3.201 mm-1, F(000) = 1309, S = 1.070, the final R = 0.0697 and wR = 0.1905 for 5368 observed reflections with I > 2σ(I). Compound 1 is built on a mixed-metal bicapped [HPMoi2V2O42] subunit covalently bonded to two [Zn(2,2'-bpy)2(H2O)]2+ clusters via terminal oxygen atoms of the capping V atoms. Each Zn atom is six-coordinated by four nitrogen atoms from two 2,2'-bpy ligands, one terminal oxygen atom from coordinated water mole cule and another one from the capped {VO} unit.

  17. Hydrothermal Synthesis and Crystal Structure of Inorganic-organic Hybrid Compound [H3NC2H4NH2]VOPO4

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    An inorganic-organic hybrid compound, [H3NC2H4NH2]VOPO4 was synthesized by meansof the hydrothermal method. It was crystallized in a monoclinic system, a space group P21/c,with the crystal cell parameters: a=0. 922 85(11) nm, b=0. 729 94(9) nm, c=0. 984 95(11)nm, β=101. 280(3)°, V=0. 650 67(13) nm3, Mr=223.02 g/mol, Dc=2. 277 g/cm3, Z=4,R= 0. 031 5, ωR= 0. 086 5, GOF = 1. 085. The VO5N octahedra chains are corner-linked byPO4 tetrahedra; the VOsN octahedra are all trans-linked with V-O bonds being alternately short and long. The monoprotonated ethylenediamine was intercalated between the layers with one end coordinating to V and the other end as an H-bond donor interacting with a terminal O atom of PO4 from a neighboring sheet. The elementary analysis, infrared spectrum characters and thermal stability were also given.

  18. Hydrothermal Synthesis and Crystal Structure of a Heterometallic Cu/Cd Complex with H2dipic (Pyridine-2,6-dicarboxylic Acid)

    Institute of Scientific and Technical Information of China (English)

    XUE Lin; CHE Yun-Xia; ZHENG Ji-Min

    2006-01-01

    A new heterometallic complex { [Cu(pic)2(H2O)2][Cd2(Hdipic)2(H2O)2Cl2] }n (Mr =1007.73) has been synthesized under hydrothermal condition and characterized by single-crystal X-ray diffraction. It crystallizes in triclinic, space group P1 with a = 5.8397(4), b = 9.8664(7), c =14. 1739(10) (A), α = 82.0150(10), β = 80.4540(10), γ= 82.3570(10)°, Z = 1, V = 792.47(10) (A)3, Dc =2.112 g/cm3, μ(MoKα) = 2.247 mm-1, F(000) = 495, the final R = 0.0232 and wR = 0.0644 for 2748observed reflections (I > 2σ(I)). In the complex, seven-coordinated Cd ions form a zigzag chain based on the alternated dinuclear Cd units. The neutral [Cu(pic)2(H2O)2] units are located at the centers of the inter space and fasten to the 1-D chain by hydrogen bonds.

  19. Hydrothermal Synthesis and Crystal Structure of a Novel Polymolybdic(VI) Acid: {[H3O]2+[Mo2O4(OH)6]2-}n

    Institute of Scientific and Technical Information of China (English)

    WANG Wei-Dong; HU Mao-Lin

    2006-01-01

    A novel supramolecular polymolybdic(VI) acid was unexpectedly synthesized by the reaction of sodium molybdate with 1,2,4,5-benzenetetracarboxylic and trichloroacetic acids in 1:1:1 molar ratio under hydrothermal condition. The crystal belongs to tetragonal with space group P4/mbm, a = 0.88867(17), b = 0.88867(17), c = 0.55676(15) nm, Z = 3, V = 0.43969(17) nm3, Dc = 4.486 g/cm3, μ = 4.365 mm-1, F(000) = 576, R = 0.0273 and wR = 0.0679. In the crystal, the Mo(VI) atoms are six- and five-coordinated in distorted octahedral and trigonal bipyramidal geometries, respectively. Furthermore, these Mo(VI) atoms, bearing different coordinated environments, are bridged by OH groups with disorder O atoms to form a two-dimensional framework with pentagonal grids. It is worthy of notice that these adjacent two-dimensional frameworks are extended into a three-dimensional supramolecular array with pentagonal large cavities'by Van Der Waals' forces and hydrogen bonding interactions.

  20. Magmatic MORB Volatiles, Seafloor Hydrothermal Systems and Abiotic Organic Synthesis

    Science.gov (United States)

    Holloway, J. R.

    2007-12-01

    A plausible model for the origin of the observed C-O-H volatiles observed in MORB glasses is that they were incorporated in primary melts of the upwelling mantle. Based on the observed ferric/ferrous ratios in MORB glass, it is probable that the MORB source mantle contained diamond or graphite, depending on pressure. If true, then during partial mantle melting the graphite/diamond would react with FeO1.5 in garnet/spinel and clinopyroxene to form CO2 which would dissolve in the melt as carbonate ion. Using equation of state models for CO2 activity and ferric/ferrous ratios in the magma it is possible to model the amount of carbonate dissolved in the basaltic magma as a function of the degree of melting (Holloway and O'Day, 2000). The results require that rising MORB magma will become saturated in CO2 at depths much greater than those proposed for MORB magma chambers. Conversely H2O values observed in MORB glasses are far below saturation. However as CO2 reaches saturation and exsolves from the melt the low fO2 imposed by the low ferric/ferrous ratio results in a high H2/H2O ratio in the exsolving supercritical fluid. We have shown that fluids with this composition produce methanol (CH3OH) in the presence of magnetite at seafloor hydrothermal P-T conditions in a flow-through system (Voglesonger, et al., 2001) and that aqueous methanol solutions react in montmorillonite clay interlayers to form a wide variety of complex hydrocarbon molecules, the most abundant being hexamethyl benzene (Williams, et al., 2005). Methyl stearate (C17H35COOCH3) was also observed in moderate amounts. Holloway, J. R. and P. A. O'Day (2000). "Production of CO2 and H2 by Diking-Eruptive Events at Mid-Ocean Ridges: Implications for Abiotic Organic Synthesis and Global Geochemical Cycling." International Geology Review 42: 673-683. Voglesonger, K. M., J. R. Holloway, E. E. Dunn, P. J. Dalla-Betta and P. A. O'Day (2001). "Experimental Abiotic Synthesis of Methanol in Seafloor Hydrothermal

  1. Hydrothermal synthesis of self-assembled hierarchical tungsten oxides hollow spheres and their gas sensing properties.

    Science.gov (United States)

    Li, Jinwei; Liu, Xin; Cui, Jiashan; Sun, Jianbo

    2015-05-20

    Hierarchical self-assembled hollow spheres (HS) of tungsten oxide nanosheets have been synthesized via a template-free hydrothermal method. Morphology evolution of the products is determined by the amount of H2C2O4 (oxalic acid) which serves as chelating agent. Structural features of the products were characterized by X-ray diffraction (XRD), and morphology was investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In addition, the porous structure was analyzed using the Brunauer-Emmett-Teller (BET) approach. The synthesis mechanism of the products with self-assembled hierarchical structures was proposed. The NO2 gas sensing properties of self-assembled hierarchical WO3 HS materials were investigated, the gas sensing properties of WO3 synthesized by a variety of formulations were compared, and the possible gas sensing mechanism was discussed. The obvious enhancement of the gas sensing properties was ascribed to the structure of the hierarchical HS.

  2. Effect of hydrothermal treatment of coal on its associative structure

    Energy Technology Data Exchange (ETDEWEB)

    Shui Heng-fu; Wang Zhi-cai; Wang Gao-qiang; Niu Min-feng [Anhui University of Technology, Maanshan (China). School of Chemistry & Chemical Engineering

    2006-10-15

    4 bituminous coals with different ranks were thermally and hydrothermally treated under different conditions, and the raw and treated coals were extracted with carbon disulfide/N-2-pyrrolidinone (CS{sub 2}/NMP) mixed solvent (1:1 by volume). It is found that the extraction yields of the thermal or hydrothermal treated coals at proper conditions increase in different extent. The increments of extraction yields for hydrothermal treated coals are higher than those of thermal treated coals. FT-IR shows that the adsorption peaks at 3410 cm{sup -1} attributed to OH group for the hydrothermal treated coals decrease, suggesting the dissociation of the coal aggregation structure due to the breakage of hydrogen bonds, resulting in the increase of extraction yields for the treated coals. For higher rank coal, the removal of minerals and the dissociation of {pi}-cation association after hydrothermal treatment of coal may be responsible for the increase of extraction yield. In addition, the mechanism of hydrothermal treatment of coal was discussed. 15 refs., 2 figs., 5 tabs.

  3. Three two-dimensional coordination polymers constructed from transition metals and 2,3-norbornanedicarboxylic acid: Hydrothermal synthesis, crystal structures and photocatalytic properties

    Science.gov (United States)

    Zhang, Jia; Wang, Chong-Chen

    2017-02-01

    Three novel coordination polymers based on transition metals like Co(II), Cu(II) and Mn(II), namely [Co2(bpy)2(nbda)2(H2O)2]·2H2O (denoted as BUC-1), [Cu2(bpy)2(nbda)2(H2O)2]·2H2O (BUC-2), [Mn2(bpy)2(nbda)2(H2O)2]·2H2O (BUC-3), (where bpy = 4,4‧-bipyridine, H2nbda = 2,3-norbornanedicarboxylic acid, BUC = Beijing University of Civil Engineering and Architecture), were synthesized under hydrothermal conditions, and characterized by CNH elemental analyses (EA), Fourier Transform infrared spectroscopy (FTIR), and single crystal X-ray diffraction (SCXRD). BUC 1-3 were isostructural and crystallized in the monoclinic space group C2/c, in which the corresponding metal atoms were linked by typical bidentate bpy ligands into two adjacent 1D [M1(bpy)]n2n+ and [M2(bpy)]n2n+ (M = Co(II), Cu(II), Mn(II)), further joined by versatile nbda2- ligands into 2D [M2(bpy)2(nbda)2]n sheets. Finally, three-dimensional supramolecular frameworks were constructed with the aid of the intermolecular hydrogen bonding interactions. BUC 1-3 exhibited different photocatalytic degradation ability to decompose methylene blue (MB) and methyl orange (MO) under UV light irradiation. Additionally, a possible photocatalytic mechanism HOMO-LUMO was proposed and discussed, which was further confirmed by radicals trapping experiments using isopropanol as radical scavenger.

  4. Synthesis and coloring properties of Cd(S1-xSex)pigments by precipitate-hydrothermal method

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Cd(S1-xSex) pigments (red to yellow) were synthesized by precipitate-hydrothermal method.The structure,morphology and hue of the powder were characterized by X-ray diffractometry (XRD),scanning electron microscopy (SEM),energy dispersive X-ray spectroscopy (EDAX) and CIE chromaticity.The optimum synthesis conditions were obtained and reaction mechanism was further analyzed as well.The results show that molar ratio of S to Se,pH value and hydrothermal reaction conditions have great effects on the hues of the pigments.Pigments with vivid hues are obtained under the conditions that pH value is about 13.0,hydrothermal reaction condition is at 140 ℃ for 4 h or at 160 ℃ for 6 h.The reaction mechanism is that Se2- of Cd(S1-xSex)substitutes S2- of CdS and then forms a continuous solid solution.

  5. Pathways for synthesis of new selenium-containing oxo-compounds: Chemical vapor transport reactions, hydrothermal techniques and evaporation method

    Science.gov (United States)

    Kovrugin, Vadim M.; Colmont, Marie; Siidra, Oleg I.; Gurzhiy, Vladislav V.; Krivovichev, Sergey V.; Mentré, Olivier

    2017-01-01

    Due to the low and close melting and sublimation temperatures (340 and 350 °C, respectively), the crystal growth of selenates and/or selenites is generally achieved using either chemical vapor transport routes, hydrothermal methods due to the good solubility and reactivity of (SeO3)2- anions or isothermal evaporation synthesis. Here we report examples many new crystal structures obtained using these synthesis routes. Particularly, description of each process is given with theoretical and practical information assorted with description of selected structures.

  6. Synthesis of non-aggregated nicotinic acid coated magnetite nanorods via hydrothermal technique

    Energy Technology Data Exchange (ETDEWEB)

    Attallah, Olivia A., E-mail: olivia.adly@hu.edu.eg [Center of Nanotechnology, Nile University, 12677 Giza (Egypt); Pharmaceutical Chemistry Department, Heliopolis University, 11777 El Salam, Cairo (Egypt); Girgis, E. [Solid State Physics Department, National Research Center, 12622 Dokki, Giza (Egypt); Advanced Materials and Nanotechnology Lab, CEAS, National Research Center, 12622 Dokki, Giza (Egypt); Abdel-Mottaleb, Mohamed M.S.A. [Center of Nanotechnology, Nile University, 12677 Giza (Egypt)

    2016-02-01

    Non-aggregated magnetite nanorods with average diameters of 20–30 nm and lengths of up to 350 nm were synthesized via in situ, template free hydrothermal technique. These nanorods capped with different concentrations (1, 1.5, 2 and 2.5 g) of nicotinic acid (vitamin B3); possessed good magnetic properties and easy dispersion in aqueous solutions. Our new synthesis technique maintained the uniform shape of the nanorods even with increasing the coating material concentration. The effect of nicotinic acid on the shape, particle size, chemical structure and magnetic properties of the prepared nanorods was evaluated using different characterization methods. The length of nanorods increased from 270 nm to 350 nm in nicotinic acid coated nanorods. Goethite and magnetite phases with different ratios were the dominant phases in the coated samples while a pure magnetite phase was observed in the uncoated one. Nicotinic acid coated magnetic nanorods showed a significant decrease in saturation magnetization than uncoated samples (55 emu/g) reaching 4 emu/g in 2.5 g nicotinic acid coated sample. The novel synthesis technique proved its potentiality to prepare coated metal oxides with one dimensional nanostructure which can function effectively in different biological applications. - Highlights: • We synthesize nicotinic acid coated magnetite nanorods via hydrothermal technique • Effect of nicotinic acid concentration on the nanorods properties was significant • Nanorods maintained uniform shape with increased concentration of nicotinic acid • Alterations occurred in particle size, mineral phases and magnetics of coated samples.

  7. Hydrothermal Synthesis of Ni/Al Layered Double Hydroxide Nanorods

    Directory of Open Access Journals (Sweden)

    Yun Zhao

    2011-01-01

    Full Text Available Ni/Al layered double hydroxide (LDH nanorods were successfully synthesized by the hydrothermal reaction. The crystal structure of the products was characterized by X-ray diffraction (XRD. The morphology of the products was observed using transmission electron microscopy (TEM and field emission scanning electron microscopy (SEM. The influences of reaction time and pH value on the morphology of the Ni/Al LDHs were investigated. The result showed that the well-crystallized nanorods of Ni/Al LDHs could be obtained when the pH value was about 10.0 with a long reaction time (12–18 h at 180°C.

  8. The Hydrothermal Autoclave Synthesis of the Nanopowders of the Refractory ZrO2 and HfO2 Oxides

    Directory of Open Access Journals (Sweden)

    N.F. Karpovich

    2015-12-01

    Full Text Available The nanopowders of the transition metal ZrO2 and HfO2 oxides were obtained by the hydrothermal autoclave synthesis. The nanoparticles possess a rounded shape and a size range of 40 to 80 nm (ZrO2, of 10 to 40 nm (HfO2. X-ray diffraction analysis and electron microscopy show that the structure of the nanoparticles is monoclinic.

  9. Hydrothermal synthesis, structure and quantum chemistry of transition metal complex supported by metal-oxo cluster [{Ni(phen)2}2(x-Mo8O26)

    Institute of Scientific and Technical Information of China (English)

    XU; Jiqing

    2001-01-01

    [1]Xu Songling, Measurement of Economic Loss of Environment Damage in China--Example and Theory, Beijing: Envi-ronment Science Press of China, 1998, 7-9.[2]Douglas, J. M., Process synthesis for waste minimization, Ind. Eng. Chem. Res., 1992, 31(1): 238.[3]Flower, J. R., Bikos, S, C., Johnson, S. W., The graphical mass balance in the early design of clean processes, Tran. of IChE, Part B, 1993, 194.[4]EI-Hakwagi, M. M., Manousiouthakis, V., Synthesis of mass exchange networks, AIChE Jl., 1989,35(8): 1233.[5]Wang, Y. P., Smith, R., Wastewater minimization, Chem. Eng. Sci., 1994, 49(7): 881.[6]Pistikopoulos, E. N., Stefanis, S. K., Livingston, A. G., A methodology for minimum environmental impact analysis, AL-CHE Symposium Series, Volume on Pollution Prevention through Process and Product Modifications, 1994, 90(303): 139.[7]Stefanis, S. K., Livingston, A. G., Pistikopoulos, E. N., Minimizing the environmental impact of process plants: A process systems methodology, Computers and Chemical Engineering, 1996, 20: S1419.[8]Rivero, R., The Exergoecologic improvement potential of industrial processes, in Proc.of TAIES'97, Beijing: World Pub-lishing Corporation, 1997, 299-304.[9]Stefanis, S. K., Buxton, A., Livingston, A. G. et al., A methodology for environmental impact minimization: Solvent des-ign and reaction path synthesis issues, Computers and Chemical Engineering, 1997, 21: S1419.[10]Rosen, M. A., Dincer, I., On exergy and environmental impact, International Journal of Energy Research, 1997, 21: 643.[11]Wang Yanfeng, Feng Xiao, Exergy analysis involving resource utilization and environmental influence, Computers and Chemical Engineering, 2000, 24: 1243.[12]Wang Jing,He Deke,Wang Yaoqu, The Handbook of Assessment Environment Data--Toxic Substance Identification Data, Beijing: Chemical Industry Press, 1988, 424-426.[13]Xiang Xinyao, Exergy Analysis Method in Engineering (in Chinese), Beijing: Petroleum Industry Press

  10. Characterization of Pr-CeO2 Nano-crystallites Prepared by Low-temperature Combustion & Hydrothermal Synthesis

    Institute of Scientific and Technical Information of China (English)

    ZHU Zhen-Feng; WANG Bao-Li; MA Jian-Zhong

    2006-01-01

    Pr-CeO2 Nano-crystalline red pigments were prepared by low-temperature combustion with a later hydrothermal treatment using Ce(NO3)3·6H2O and Pr6O11 as raw materials. The phase composition, coloring mechanism and morphology of pigments were analyzed by XRD, SEM,EDS and XPS. Results showed that Pr-CeO2 solid solution with a fluorite structure was obtained by the diffusion of Pr+3 into CeO2 crystal lattice during the synthesis process. XPS analysis indicated that Pr+3 substitutes Ce+4 in CeO2 and is compensated by oxygen vacancies. Compared with low-temperature combustion synthesis, the Pr-CeO2 pigments prepared with a subsequent hydrothermal treatment have an average grain size of about 16.70 nm, and the crystallinity and red tonality are improved.

  11. Programing Structural Synthesis System

    Science.gov (United States)

    Rogers, James L., Jr.

    1986-01-01

    Program aids research in analysis and optimization. Programing Structural Synthesis System (PROSSS2) developed to provide structural-synthesis capability by combining access to SPAR with CONMIN program and set of interface procedures. SPAR is large general-purpose finite-element structural-analysis program, and CONMIN is large general-purpose optimization program. PROSSS2 written in FORTRAN IV for batch execution.

  12. Hydrothermal Synthesis, Structure and Fluorescent Property of a Coordination Compound of Uranyl(Ⅵ)%一种铀(Ⅵ)配合物的水热合成、结构与性质

    Institute of Scientific and Technical Information of China (English)

    金杨波; 胡斌; 李永绣; 王国喜

    2008-01-01

    UO2(EPC)2 (EPC=5-ethyl-3-pyridinecarboxylate) was synthesized by the hydrothermal reaction of UO2(NO3)2 carboxylic acid] at 120 ℃, which 2-(4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl group was removed under this condition to result in the formation of 5-ethyl-3-pyridinecarboxylate ligand (EPC). The structure and fluorescent property of the synthesized complex is also reported. CCDC: 645641.

  13. Hydrothermal synthesis of high surface area ZIF-8 with minimal use of TEA

    Science.gov (United States)

    Butova, V. V.; Budnyk, A. P.; Bulanova, E. A.; Lamberti, C.; Soldatov, A. V.

    2017-07-01

    In this paper we present, for the first time, a simple hydrothermal recipe for the synthesis of ZIF-8 Metal-Organic Framework (MOF) with a large specific surface area (1340 m2/g by BET). An important feature of the method is that the product forms in aqueous medium under standard hydrothermal conditions without DMF and great excess of linker with the use of TEA as structure directing agent. The ZIF-8 crystal phase of the product was confirmed by XRD; this technique has been also exploited to check the crystallinity and to follow the changes in the MOF structure induced by heating. TGA and temperature dependent XRD testify the high thermal stability of the material (470 °C in N2 and at 400 °C in air). The IR spectral profile of the material provides a complete picture of vibrations assigned to the linker and the metal center. The systematic investigation of the products obtained by increasing the TEA amount in the reacting medium from 0 to 25.5 mol equivalent Zn2+, allowed us to understand its role and to find 2.6 mol equivalent Zn2+ as the minimum amount needed to obtain a single phase ZIF-8 material with the high standard reported above. The stability of the material under severe basic conditions makes it a promising candidate in heterogeneous catalysis. The material has shown high capacity in I2 uptake, making it interesting also for selective molecular adsorption.

  14. Hydrothermal Synthesis Au-Bi2Te3 Nanocomposite Thermoelectric Film with a Hierarchical Sub-Micron Antireflection Quasi-Periodic Structure

    Directory of Open Access Journals (Sweden)

    Junlong Tian

    2015-06-01

    Full Text Available In this work, Au-Bi2Te3 nanocomposite thermoelectric film with a hierarchical sub-micron antireflection quasi-periodic structure was synthesized via a low-temperature chemical route using Troides helena (Linnaeus forewing (T_FW as the biomimetic template. This method combines chemosynthesis with biomimetic techniques, without the requirement of expensive equipment and energy intensive processes. The microstructure and the morphology of the Au-Bi2Te3 nanocomposite thermoelectric film was analyzed by X-ray diffraction (XRD, field-emission scanning-electron microscopy (FESEM, and transmission electron microscopy (TEM. Coupled the plasmon resonances of the Au nanoparticles with the hierarchical sub-micron antireflection quasi-periodic structure, the Au-Bi2Te3 nanocomposite thermoelectric film possesses an effective infrared absorption and infrared photothermal conversion performance. Based on the finite difference time domain method and the Joule effect, the heat generation and the heat source density distribution of the Au-Bi2Te3 nanocomposite thermoelectric film were studied. The heterogeneity of heat source density distribution of the Au-Bi2Te3 nanocomposite thermoelectric film opens up a novel promising technique for generating thermoelectric power under illumination.

  15. Hydrothermal Synthesis, Crystal Structure and Electrochemical Properties of the Complex Cu(o-Methylbenzoic acid)2(2,2'-bipy)·(H2O)

    Institute of Scientific and Technical Information of China (English)

    HE Xiao-Mei; LI Chang-Hong; YANG Ying-Qun; LI Wei

    2007-01-01

    The title complex (C26H24CuN2O5, Mr = 508.01) has been synthesized by o-methylbenzoic acid, 2,2'-bipyridine (bipy) and copper perchlorate in the mixed solvent of water and methanol. It crystallizes in orthorhombic, space group P212121 with a = 0.70814(10), b = 1.6953(3),c = 1.9539(3) nm, V= 2.3457(6) nm3, Dc= 1.439 g/cm3, Z= 4,μ = 0.971 mm-1, F(000) = 1052, R= 0.0432 and wR = 0.0860. The structural determination shows that the copper atom is coordinated by three oxygen atoms from two o-methylbenzoic acids and one water molecule together with two nitrogen atoms from 2,2'-bipyridine, giving a distorted square-pyramidal coordination geometry.The cyclic voltammetric behavior of the complex is also discussed.

  16. Sol-Gel/Hydrothermal Synthesis of Mixed Metal Oxide

    African Journals Online (AJOL)

    Mixed metal oxides of titanium and zinc nanocomposites were prepared through sol-gel method under hydrothermal ... the production of TiO -ZnO nanoparticles use. 2 either titanium ... involved using titanium sulphate and thioacetamide for ...

  17. Hydrothermal synthesis of porous Co(OH)2 nanoflake array film and its supercapacitor application

    Indian Academy of Sciences (India)

    Z Chen; Y Chen; C Zuo; S Zhou; A G Xiao; A X Pan

    2013-04-01

    Porous -Co(OH)2 nanoflake array film is prepared by a facile hydrothermal synthesis method. The -Co(OH)2 nanoflake array film exhibits a highly porous net-like structure composed of interconnected nanoflakes with a thickness of 15 nm. The pseudo-capacitive behaviour of the Co(OH)2 nanoflake array film is investigated by cyclic voltammograms (CV) and galvanostatic charge–discharge tests in 2MKOH. The -Co(OH)2 nanoflake array film exhibits high capacitances of 1017 F g-1 at 2Ag-1 and 890 F g-1 at 40Ag-1 as well as rather good cycling stability for supercapacitor application. The porous architecture is responsible for the enhancement of the electrochemical properties because it provides fast ion and electron transfer, large reaction surface area and good strain accommodation.

  18. Hydrothermal synthesis of meso porous silica MCM-41 using commercial sodium silicate

    Energy Technology Data Exchange (ETDEWEB)

    Melendez O, H. I.; Mercado S, A.; Garcia C, L. A.; Castruita, G.; Perera M, Y A., E-mail: ivan_melendez380@hotmail.com [Centro de Investigacion en Quimica Aplicada, Bldv. Enrique Reyna Hermosillo No. 140, Saltillo 25294, Coahuila (Mexico)

    2013-08-01

    In this work, ordered meso porous silica MCM-41 was prepared by hydrothermal synthesis using industrial-grade sodium silicate (Na{sub 2}SiO{sub 3}) as silica source, hexadecyltrimethyl-ammonium bromide (CTAB) as template agent and ethyl acetate as ph regulator. The influence of CTAB/SiO{sub 2} molar ratio, reaction time, aging temperature, and co-surfactant type on the structural and morphological properties of the obtained silica was studied. The products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and nitrogen adsorption-desorption isotherms. Ordered meso porous MCM-41 silica was obtained at 80 C by using a range of CTAB/SiO{sub 2} molar ratio from 0.35 to 0.71 and reaction times up to 72 h and isopropanol (i-Pr OH) as co-surfactant. (Author)

  19. Hydrothermal Synthesis of WO3 Nanowires in the Presence of Guanidine Sulfate and Its Photocatalytic Activity

    Institute of Scientific and Technical Information of China (English)

    MU Wanjun; YU Qianhong; LI Xingliang; WEI Hongyuan; JIAN Yuan

    2016-01-01

    WO3 nanowires were fabricated by a hydrothermal method, which proceeded at 170℃ for 48 h in a solution containing C2H10N6H2SO4 as a dispersant and Na2WO4 as a starting material. The nanowires exhibit a well crystallized one-dimensional structure with 20 nm in diameter and several microns in length. The physicochemical properties of WO3 were compared using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX) and UV-vis spectroscopy (UV-Vis). The photoactivity of the as-perpared WO3 nanowires was evaluated through the photodegradation of methylene blue (MB) in aqueous solution. The experimental results demonstrate that addition of C2H10N6H2SO4 salt in the WO3 nanowires synthesis process can enhance its photocatalytic activity obviously.

  20. Green hydrothermal synthesis and optical properties of γ-Gd2S3 nanoparticles

    Science.gov (United States)

    Khajuria, Sonika; Ladol, Jigmet; Sanotra, Sumit; Sheikh, Haq Nawaz

    2016-06-01

    Green synthesis of γ-Gd2S3 nanoparticles was carried out using low-temperature hydrothermal route in autoclave. A 1:1 mixture of ionic liquid 1-ethyl-3-methylimidazolium ethyl sulfate, ([EMIM][EtSO4]), and water was used as a solvent. Synthesized nanoparticles were characterized by x-ray powder diffraction (XRPD), scanning electron microscopy (SEM), UV-visible spectroscopy (UV-vis), particle size by dynamic light scattering (DLS) technique, and photoluminescence (PL) studies. XRPD suggests cubic Th3P4-type structure for obtained Gd2S3 nanoparticles. The size of synthesized nanoparticles is about 86 nm. Optical band gap for these nanoparticles estimated from electronic spectrum is 2.95 eV which shows blue shift from values reported for bulk Gd2S3 due to pronounced quantum mechanical effect. These nanoparticles show sharp emission peak at 385 nm and a broad shoulder at 475 nm when excited at 260 nm.

  1. Microwave-assisted hydrothermal synthesis and gas sensitivity of nanostructured SnO2

    Institute of Scientific and Technical Information of China (English)

    Liying Man; Jun Zhang; Jieqiang wang; Hongyan Xu; Bingqiang Cao

    2013-01-01

    Precursors for nanostructured SnO2 were synthesized via a microwave-assisted hydrothermal method under different conditions,using SnCl2·2H2O,urea and citric acid as reactants.After calcination of the precursors at 700 ℃ for 2 h.nanostructured SnO2 with different morphologies were obtained,and were then characterized using X-ray powder diffraction (XRD),and field-emission scanning electron microscopy (FESEM).The results show that synthesis temperature and time play an important role in the formation of the 3D hierarchical morphology of the nanostructured SnO2.Gas sensing experiments demonstrate that the synthesized SnO2 materials,especially those with a 3D network structure,exhibit superb sensitivity to alcohol vapors at 240 ℃.

  2. Hydrothermal synthesis for new multifunctional materials: A few examples of phosphates and phosphonate-based hybrid materials

    Science.gov (United States)

    Rueff, Jean-Michel; Poienar, Maria; Guesdon, Anne; Martin, Christine; Maignan, Antoine; Jaffrès, Paul-Alain

    2016-04-01

    Novel physical or chemical properties are expected in a great variety of materials, in connection with the dimensionality of their structures and/or with their nanostructures, hierarchical superstructures etc. In the search of new advanced materials, the hydrothermal technique plays a crucial role, mimicking the nature able to produce fractal, hyperbranched, urchin-like or snow flake structures. In this short review including new results, this will be illustrated by examples selected in two types of materials, phosphates and phosphonates, prepared by this method. The importance of the synthesis parameters will be highlighted for a magnetic iron based phosphates and for hybrids containing phosphonates organic building units crystallizing in different structural types.

  3. Formation Mechanism of Nanosized Tin Oxide (SnO2) Powder During Hydrothermal Synthesis

    OpenAIRE

    M. Ozan ÖZER; Suvaci, Ender; DOĞAN, Aydın

    2011-01-01

    Preparation of nanosized SnO2 electroceramic powders via hydrothermal synthesis was investigated as a function of initial concentration and treatment time in order to understand the formation and growth mechanisms.  SnO2 powder was successfully synthesized from the hydrous tin oxide by hydrothermal synthesis at 200°C.  Crystalline SnO2 particles with a specific surface area as high as 170 m2/g were produced in a single step without requiring any calcination process.  As ini...

  4. Effect of additive on synthesis of MnZn ferrite nanocrystal by hydrothermal crystallization

    Institute of Scientific and Technical Information of China (English)

    桑商斌; 古映莹; 黄可龙

    2003-01-01

    The effect of additive RCOONa on the formation of MnZn ferrite homogeneous coprecipitation precursor was studied in this paper. The action of additive in the MnZn ferrite hydrothermal crystallization process was investigated according to crystal field theory and crystal growth unit theory. And the growth unit formation process was presented and its structure was illustrated. The results show that the precursor of MnZn ferrite is a colloidal mixture composed of Zn(OH)2, Fe(OH)2, Mn(OH)2, MnO(OH) , MnO2 @ xH2O and so on, and dissolves in solution in the form of hydroxyl coordination tetrahedron and octahedron such as Zn(OH)2-4,Fe(OH)2-4 , Fe(OH)4-6 ,Fe(OH)-4 , Fe(OH)3-6 ,Mn(OH)2-4 ,Mn(OH)3-6 etc. , and the growth unit is formed by combination of the coordination polyhedra subsequently in the hydrothermal precess. The additive is beneficial to the formation of homogeneous precursor and has dispersive effect on the aggregation of the crystal growth unit by forming associate with hydrogen bond,which is beneficial to the synthesis of the pure product with a tiny size and a narrow size distribution.

  5. Hydrothermal synthesis of mesoporous metal oxide arrays with enhanced properties for electrochemical energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Anguo, E-mail: hixiaoanguo@126.com; Zhou, Shibiao; Zuo, Chenggang; Zhuan, Yongbing; Ding, Xiang

    2015-01-15

    Highlights: • NiO mesoporous nanowall arrays are prepared via hydrothermal method. • Mesoporous nanowall arrays are favorable for fast ion/electron transfer. • NiO mesoporous nanowall arrays show good supercapacitor performance. - Abstract: Mesoporous nanowall NiO arrays are prepared by a facile hydrothermal synthesis method with a following annealing process. The NiO nanowall shows continuous mesopores ranging from 5 to 10 nm and grows vertically on the substrate forming a porous net-like structure with macropores of 20–300 nm. A plausible mechanism is proposed for the growth of mesoporous nanowall NiO arrays. As cathode material of pseudocapacitors, the as-prepared mesoporous nanowall NiO arrays show good pseudocapacitive performances with a high capacitance of 600 F g{sup −1} at 2 A g{sup −1} and impressive high-rate capability with a specific capacitance of 338 F g{sup −1} at 40 A g{sup −1}. In addition, the mesoporous nanowall NiO arrays possess good cycling stability. After 6000 cycles at 2 A g{sup −1}, a high capacitance of 660 F g{sup −1} is attained, and no obvious degradation is observed. The good electrochemical performance is attributed to its highly porous morphology, which provides large reaction surface and short ion diffusion paths, leading to enhanced electrochemical properties.

  6. Hydrothermal Synthesis and Characterization of Europium-dop ed Barium Titanate Nano crys-tallites

    Institute of Scientific and Technical Information of China (English)

    Margarita Garca-Hernandez; Genevieve Chadeyron; Damien Boyer; Antonieta Garca-Murillo; Felipe Carrillo-Romo; Rachid Mahiou

    2013-01-01

    Barium titanate nanocrystallites were synthesized by a hydrothermal technique from barium chlo-ride and tetrabutyl titanate. Single-crystalline cubic perovskite BaTiO3 consisting of spherical particles with diameters ranging from 10 to 30 nm was easily achieved by this route. In order to study the influence of the syn-thesis process on the morphology and the optical properties, barium titanate was also prepared by a solid-state reaction. In this case, only the tetragonal phase which crystallizes above 900℃ was observed. High-temperature X-ray diffraction measurements were performed to investigate the crystallization temperatures as well as the particle sizes via the Scherrer formula. The lattice vibrations were evidenced by infrared spectroscopy. Eu3+was used as a structural probe, and the luminescence properties recorded from BaTiO3:Eu3+and elaborated by a solid-state reaction and hydrothermal process were compared. The reddish emission of the europium is increased by the nanometric particles.

  7. Flow and permeability structure of the Beowawe, Nevada hydrothermal system

    Energy Technology Data Exchange (ETDEWEB)

    Faulder, D.D. [Lockheed Idaho Technologies Co., Idaho Falls, ID (United States); Johnson, S.D.; Benoit, W.R. [Oxbow Power Services, Inc., Reno, NV (United States)

    1997-05-01

    A review of past geologic, geochemical, hydrological, pressure transient, and reservoir engineering studies of Beowawe suggests a different picture of the reservoir than previously presented. The Beowawe hydrothermal contains buoyant thermal fluid dynamically balanced with overlying cold water, as shown by repeated temperature surveys and well test results. Thermal fluid upwells from the west of the currently developed reservoir at the intersection of the Malpais Fault and an older structural feature associated with mid-Miocene rifting. A tongue of thermal fluid rises to the east up the high permeability Malpais Fault, discharges at the Geysers area, and is in intimate contact with overlying cooler water. The permeability structure is closely related to the structural setting, with the permeability of the shallow hydrothermal system ranging from 500 to 1,000 D-ft, while the deeper system ranges from 200 to 400 D-ft.

  8. Hydrothermal reactions: From the synthesis of ligand to new lanthanide 3D-coordination polymers

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Fausthon Fred da; Fernandes de Oliveira, Carlos Alberto; Lago Falcão, Eduardo Henrique [Laboratório de Terras Raras, Departamento de Química Fundamental, Universidade Federal de Pernambuco (DQF-UFPE), 50590-470 Recife, PE (Brazil); Gatto, Claudia Cristina [Laboratório de Síntese Inorgânica e Cristalografia, Instituto de Química, Universidade de Brasília (IQ-UnB), 70904-970 Brasilia, DF (Brazil); Bezerra da Costa, Nivan; Oliveira Freire, Ricardo [Pople Computational Chemistry Laboratory, Departamento de Química, Universidade Federal de Sergipe, São Cristóvão-SE 49100-000 (Brazil); Chojnacki, Jarosław [Department of Inorganic Chemistry, Gdansk University of Technology, 80-233 Gdansk (Poland); Alves Júnior, Severino, E-mail: salvesjr@ufpe.br [Laboratório de Terras Raras, Departamento de Química Fundamental, Universidade Federal de Pernambuco (DQF-UFPE), 50590-470 Recife, PE (Brazil)

    2013-11-15

    The organic ligand 2,5-piperazinedione-1,4-diacetic acid (H{sub 2}PDA) was synthesized under hydrothermal conditions starting from the iminodiacetic acid and catalyzed by oxalic acid. The X-ray powder diffraction data indicates that the compound crystallizes in the P2{sub 1}/c monoclinic system as reported in the literature. The ligand was also characterized by elemental analysis, magnetic nuclear resonance, infrared spectroscopy and thermogravimetric analysis. Two new coordination networks based on lanthanide ions were obtained with this ligand using hydrothermal reaction. In addition to single-crystal X-ray diffraction, the compounds were characterized by infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy and elemental analysis. Single-crystal XRD showed that the compounds are isostructural, crystallizing in P2{sub 1}/n monoclinic system with chemical formula [Ln(PDA){sub 1.5}(H{sub 2}O)](H{sub 2}O){sub 3} (Ln=Gd{sup 3+}(1) and Eu{sup 3+}(2)).The luminescence properties of both compounds were studied. In the compound (1), a broad emission band was observed at 479 nm, redshifted by 70 nm in comparison of the free ligand. In (2), the typical f–f transition was observed with a maximum peak at 618 nm, related with the red emission of the europium ions. Computational methods were performed to simulate the crystal structure of (2). The theoretical calculations of the intensity parameters are in good agreement with the experimental values. - Graphical abstract: Scheme of obtaining the ligand 2,5-piperazinedione-1,4-diacetic acid (H{sub 2}PDA) and two new isostructural 3D-coordination polymers [Ln(PDA){sub 1.5}(H{sub 2}O)](H{sub 2}O){sub 3} (Ln=Gd{sup 3+} and Eu{sup 3+}) by hydrothermal synthesis. Display Omitted - Highlights: • The ligand 2,5-piperazinedione-1,4-diacetic acid was synthetized using the hydrothermic method and characterized. • Two new 3D-coordination polymers with this ligand containing Gd{sup 3+} and Eu{sup 3+} ions

  9. A NOVEL HYDROTHERMAL SYNTHESIS METHOD FOR BARIUM FERRITE

    Institute of Scientific and Technical Information of China (English)

    Kang Li; Hongchen Gu; Qun Wei

    2004-01-01

    In the present work, fine barium ferrite powder has been synthesized through a one-step hydrothermal process in an autoclave at [OH-]/[Cl-] ratio of 2:1 in the temperature range from 180 to 260 ℃ using barium chloride (BaCl2), ferrous chloride (FeCl2) and potassium nitrate (KNO3) as the starting materials. Both particle size and saturation magnetization (Ms) increase with increasing hydrothermal reaction temperature, while the intrinsic coercivity (iHc) peaks at 685 Oe at 230 ℃. Morphology progress from the barium ferrite precursor particles to the barium hexaferrite particles has been monitored with increasing hydrothermal reaction time at 230 ℃ in the autoclave.

  10. Influence of hydrothermal synthesis parameters on the properties of hydroxyapatite nanoparticles

    Directory of Open Access Journals (Sweden)

    Sylwia Kuśnieruk

    2016-11-01

    Full Text Available Hydroxyapatite (HAp nanoparticles of tunable diameter were obtained by the precipitation method at room temperature and by microwave hydrothermal synthesis (MHS. The following parameters of the obtained nanostructured HAp were determined: pycnometric density, specific surface area, phase purity, lattice parameters, particle size, particle size distribution, water content, and structure. HAp nanoparticle morphology and structure were determined using scanning electron microscopy (SEM and transmission electron microscopy (TEM. X-ray diffraction measurements confirmed crystalline HAp was synthesized, which was pure in terms of phase. It was shown that by changing the synthesis parameters, the diameter of HAp nanoparticles could be controlled. The average diameter of the HAp nanoparticles was determined by Scherrer’s equation via the Nanopowder XRD Processor Demo web application, which interprets the results of specific surface area and TEM measurements using the dark-field technique. The obtained nanoparticles with average particle diameter ranging from 8–39 nm were characterized by having homogeneous morphology with a needle shape and a narrow particle size distribution. Strong similarities were found when comparing the properties of some types of nanostructured hydroxyapatite with natural occurring apatite found in animal bones and teeth.

  11. Conventional and microwave hydrothermal synthesis of monodispersed metal oxide nanoparticles at liquid-liquid interface

    Science.gov (United States)

    Monodispersed nanoparticles of metal oxide including ferrites MFe2O4 (M=, Ni, Co, Mn) and γ-Fe2O3, Ta2O5 etc. have been synthesized using a water-toluene interface under both conventional and microwave hydrothermal conditions. This general synthesis procedure uses readily availab...

  12. Lipid Synthesis Under Hydrothermal Conditions by Fischer- Tropsch-Type Reactions

    Science.gov (United States)

    McCollom, Thomas M.; Ritter, Gilles; Simoneit, Bernd R. T.

    1999-03-01

    Ever since their discovery in the late 1970's, mid-ocean-ridge hydrothermal systems have received a great deal of attention as a possible site for the origin of life on Earth (and environments analogous to mid-ocean-ridge hydrothermal systems are postulated to have been sites where life could have originated on Mars and elsewhere as well). Because no modern-day terrestrial hydrothermal systems are free from the influence of organic compounds derived from biologic processes, laboratory experiments provide the best opportunity for confirmation of the potential for organic synthesis in hydrothermal systems. Here we report on the formation of lipid compounds during Fischer-Tropsch-type synthesis from aqueous solutions of formic acid or oxalic acid. Optimum synthesis occurs in stainless steel vessels by heating at 175 °C for 2-3 days and produces lipid compounds ranging from C2 to >C35 which consist of n-alkanols, n- alkanoic acids, n-alkenes, n-alkanes and alkanones. The precursor carbon sources used are either formic acid or oxalic acid, which disproportionate to H2, CO2 and probably CO. Both carbon sources yield the same lipid classes with essentially the same ranges of compounds. The synthesis reactions were confirmed by using 13C labeled precursor acids.

  13. Hydrothermal synthesis and photoluminescent properties of stacked indium sulfide superstructures.

    Science.gov (United States)

    Xing, Yan; Zhang, Hongjie; Song, Shuyan; Feng, Jing; Lei, Yongqian; Zhao, Lijun; Li, Meiye

    2008-03-28

    Unusual hierarchical stacked superstructures of cubic beta-In2S3 were fabricated via a facile hydrothermal process in the presence of a surfactant cetyltrimethylammonium bromide CTAB; the 3D superstructures were developed by helical propagation of surface steps from microflakes of 10-20 nm thickness.

  14. Influence of bases on hydrothermal synthesis of titanate nanostructures

    CSIR Research Space (South Africa)

    Sikhwivhilu, LM

    2009-03-01

    Full Text Available A hydrothermal treatment of titanium dioxide (TiO2) with various bases (i.e., LiOH, NaOH, KOH, and NH4OH) was used to prepare materials with unique morphologies, relatively small crystallite sizes, and large specific surface areas. The experimental...

  15. Selective synthesis and growth mechanism of CeVO4 nanoparticals via hydrothermal method

    Institute of Scientific and Technical Information of China (English)

    LIU Fengzhen; SHAO Xin; YIN Yibin; ZHAO Limin; SUN Qiaozhen; SHAO Zhuwei; LIU Xuehua; MENG Xianhua

    2011-01-01

    Selective-controlled structure and shape of CeVO4 nanocrystals were successfully synthesized via a hydrothermal method from electron microscopy (FESEM) and energy dispersive spectroscopy (EDS). The influence of hydrothermal temperature, precursor solution concentration on the crystal and morphology of products were further studied. The results showed that the as-synthesized products exhibited pure single-crystal CeVO4 nanoparticles with tetragonal structure. The hydrothermal temperature and precursor solution concentration had important effects on the formation of CeVO4 nanoparticles. Furthermore, the growth mechanism of CeVO4 nanoparticles was explained with Ostwald ripening mechanism.

  16. Prebiotic Synthesis of Glycine from Ethanolamine in Simulated Archean Alkaline Hydrothermal Vents

    Science.gov (United States)

    Zhang, Xianlong; Tian, Ge; Gao, Jing; Han, Mei; Su, Rui; Wang, Yanxiang; Feng, Shouhua

    2016-09-01

    Submarine hydrothermal vents are generally considered as the likely habitats for the origin and evolution of early life on Earth. In recent years, a novel hydrothermal system in Archean subseafloor has been proposed. In this model, highly alkaline and high temperature hydrothermal fluids were generated in basalt-hosted hydrothermal vents, where H2 and CO2 could be abundantly provided. These extreme conditions could have played an irreplaceable role in the early evolution of life. Nevertheless, sufficient information has not yet been obtained for the abiotic synthesis of amino acids, which are indispensable components of life, at high temperature and alkaline condition. This study aims to propose a new method for the synthesis of glycine in simulated Archean submarine alkaline vent systems. We investigated the formation of glycine from ethanolamine under conditions of high temperature (80-160 °C) and highly alkaline solutions (pH = 9.70). Experiments were performed in an anaerobic environment under mild pressure (0.1-8.0 MPa) at the same time. The results suggested that the formation of glycine from ethanolamine occurred rapidly and efficiently in the presence of metal powders, and was favored by high temperatures and high pressures. The experiment provides a new pathway for prebiotic glycine formation and points out the phenomenal influence of high-temperature alkaline hydrothermal vents in origin of life in the early ocean.

  17. Synthesis of non-aggregated nicotinic acid coated magnetite nanorods via hydrothermal technique

    Science.gov (United States)

    Attallah, Olivia A.; Girgis, E.; Abdel-Mottaleb, Mohamed M. S. A.

    2016-02-01

    Non-aggregated magnetite nanorods with average diameters of 20-30 nm and lengths of up to 350 nm were synthesized via in situ, template free hydrothermal technique. These nanorods capped with different concentrations (1, 1.5, 2 and 2.5 g) of nicotinic acid (vitamin B3); possessed good magnetic properties and easy dispersion in aqueous solutions. Our new synthesis technique maintained the uniform shape of the nanorods even with increasing the coating material concentration. The effect of nicotinic acid on the shape, particle size, chemical structure and magnetic properties of the prepared nanorods was evaluated using different characterization methods. The length of nanorods increased from 270 nm to 350 nm in nicotinic acid coated nanorods. Goethite and magnetite phases with different ratios were the dominant phases in the coated samples while a pure magnetite phase was observed in the uncoated one. Nicotinic acid coated magnetic nanorods showed a significant decrease in saturation magnetization than uncoated samples (55 emu/g) reaching 4 emu/g in 2.5 g nicotinic acid coated sample. The novel synthesis technique proved its potentiality to prepare coated metal oxides with one dimensional nanostructure which can function effectively in different biological applications.

  18. Hydrothermal Synthesis of Xonotlite-type Calcium Silicate Insulation Material Using Industrial Zirconium Waste Residue

    Institute of Scientific and Technical Information of China (English)

    JIANG Jinguo; CUI Chong; LIU Jinqiang; LIAO Wenli

    2011-01-01

    Xonotlite-type insulation material was prepared by hydrothermal synthesis technology using industrial zirconium waste residue in this paper, and the phase analysis together with the observation of micro-morphology were also carried out by XRD, SEM and TEM. The density and thermal conductivity were measured finally. The results indicate, chlorine ion impurity contained in zirconium waste residue can be removed effectively via water washed process, and the reactive activity of silicon dioxide is almost not affected,which make it be a good substitution of silicon material for the preparation of calcium silicate insulation material by hydrothermal synthesis technique. The density and thermal conductivity of xonotlite-type calcium silicate insulation material obtained by hydrothermal synthesis technique can reach 159 kg/m3, 0.049 W/(m·°C), respectively, meeting with National Standard well, when synthesis conditions are selected as follows: Ca/Si molar ratio equal to 1, synthesis temperature at 210 ℃ and kept for 8 hrs. It provides a new approach to realize lightweight and low thermal conductivity of calcium silicate insulation material.

  19. Evaluating Experimental Artifacts in Hydrothermal Prebiotic Synthesis Experiments

    Science.gov (United States)

    Smirnov, Alexander; Schoonen, Martin A. A.

    2003-04-01

    Control experiments with ultra pure deionized water were conducted to evaluate the organic contamination in hydrothermal prebiotic experiments. Different combinations of reaction vessel material, sampling tubing and stirring were tested and the amounts of organic contaminants determined. All tested types of polymer tubing were proven to introduce organic contaminants (formate, acetate and propionate ions) into the reacting solution. Stainless steel has a catalytic effect on the decomposition of formate, consistent with earlier work at high temperatures and pressures.

  20. Hydrothermal synthesis of zeolites from coal fly ash

    OpenAIRE

    Kotova, OB; Shabalin, Igor L; Shushkov, DA; Kocheva, LS

    2015-01-01

    The fly ash, from the combustion of coal to produce energy and heat, is an industrial waste, in which large accumulations represent a serious environmental threat. To reduce the environmental burden and improve the economic benefits of energy production, the science and industry focus on the transformation of coal combustion byproducts into new functional materials. The fly ash was studied by modern analytical methods. As a result of the hydrothermal reaction, several types of zeolites were s...

  1. Rapid Synthesis of Carbon Dots by Hydrothermal Treatment of Lignin

    Directory of Open Access Journals (Sweden)

    Wenxin Chen

    2016-03-01

    Full Text Available A rapid approach has been developed for the fluorescent carbon dots (CDs by the hydrothermal treatment of lignin in the presence of H2O2. The as-synthesized CDs were found to emit blue photoluminescence with excellent photostability. Moreover, the CDs displayed biocompatibility, low cytotoxicity, and high water solubility properties. Finally, the as-resulted CDs were demonstrated to be excellent probes for bioimaging and biosensing applications.

  2. Experimental Investigation of Organic Synthesis in Hydrothermal Environments

    Science.gov (United States)

    Shock, Everett L.

    1998-01-01

    The results of the investigation were presented at a Astrobiology Institute General Meeting. Seafloor hydrothermal systems may be the most likely locations on the early Earth for the emergence of life. Because of the disequilibrium inherent in such dynamic, mixing environments, abundant chemical energy would have been available for formation of the building blocks of life. In addition, theoretical studies suggest that organic compounds in these conditions would reach metastable states, due to kinetic barriers to the formation of stable equilibrium products (CO2 and methane). The speciation of organic carbon in metastable states is highly dependent on the oxidation state, pH, temperature, pressure and bulk composition of the system. The goal of our research is to investigate the effects of a number external variables on the formation, transformation, and stability of organic compounds at hydrothermal conditions. We have begun experimental work to attempt to control the oxidation state of simulated hydrothermal systems by using buffers composed of mineral powders and gas mixtures. We are also beginning to test the stability of organic compounds under these conditions.

  3. Hydrothermal synthesis of nanosize phases based on non-ferrous and noble metals

    Energy Technology Data Exchange (ETDEWEB)

    Tupikova, E. N., E-mail: nil-6ssau@mail.ru; Platonov, I. A., E-mail: pia@ssau.ru; Lykova, T. N. [Samara state aerospace university (SSAU) Moskovskoye shosse 34, Samara, 443086 (Russian Federation)

    2016-04-13

    Research is devoted to reactions of binary complexes containing noble (platinum, palladium) and non-ferrous (cobalt, chrome) metals. Reactions proceed under hydrothermal conditions by the autoclave technique. Initials complexes and products of autoclave thermolysis were characterized by the FT-IR spectroscopy, the transmission electron microscopy (TEM) and the energy-dispersive X-ray spectroscopy (EDX). Comparative catalytic experiments in the test reaction were conducted. The obtained results can form the basis of new methods of nanosize multicomponent phases synthesis under hydrothermal conditions.

  4. Hydrothermal synthesis of mixed rare earth-alkali metal or ammonium fluorides

    Institute of Scientific and Technical Information of China (English)

    由芳田; 黄世华; 时秋峰

    2010-01-01

    The recent results on hydrothermal synthesis of mixed rare earth-alkali or ammonium fluorides were presented. The initial ratios of the starting materials, pH value and reaction temperature were the critical factors for obtaining the single-phase product. Four main types of complex rare earth fluorides, AREF4, A2REF5, ARE2F7 and ARE3F10 (A=Na+, K+, Rb+, NH4+), appeared in the primary hydrothermal reactions. The correlation between cation sizes and the formation of mixed rare earth fluorides under mild hydro...

  5. Effect of pH on the Hydrothermal Synthesis of BN Nanocrystals

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Boron nitride (BN) has been synthesized using hydrothermal synthesis method. The experimental results showed that the pH value of the reaction solution has an important effect on the yield and phases of BN samples. As the pH value decreased, the content of cBN increased and the yield improved. The increase in cBN content is resulted from the conversion of oBN into cBN under hydrothermal condition, and the growth of cBN nanocrystals may due to the decrease in the reaction speed, thus the crystalline perfection of BN improved when the pH value decreased.

  6. Direct hydrothermal synthesis of novel functional mesoporous materials

    Institute of Scientific and Technical Information of China (English)

    WU Zhengying; WEI Yilun; WANG Yimeng; ZHU Jianhua

    2004-01-01

    A direct synthesis method of preparing alkaline earth or transition metal oxides supporting mesoporous materials is reported. Distinguishing from those traditional techniques characterized by "synthesis at first and then modification", this new method adds the precursor salts that have no perturbation in the strong acid synthetic system but easily form oxides after calcinations, into the initial synthetic mixture, performing the "synthesis" and "modification" in one-pot procedure.

  7. Evaluating structure selection in the hydrothermal growth of FeS2 pyrite and marcasite

    Science.gov (United States)

    Kitchaev, Daniil A.; Ceder, Gerbrand

    2016-12-01

    While the ab initio prediction of the properties of solids and their optimization towards new proposed materials is becoming established, little predictive theory exists as to which metastable materials can be made and how, impeding their experimental realization. Here we propose a quasi-thermodynamic framework for predicting the hydrothermal synthetic accessibility of metastable materials and apply this model to understanding the phase selection between the pyrite and marcasite polymorphs of FeS2. We demonstrate that phase selection in this system can be explained by the surface stability of the two phases as a function of ambient pH within nano-size regimes relevant to nucleation. This result suggests that a first-principles understanding of nano-size phase stability in realistic synthesis environments can serve to explain or predict the synthetic accessibility of structural polymorphs, providing a guideline to experimental synthesis via efficient computational materials design.

  8. SDS-assisted hydrothermal synthesis of porous CdIn2S4 microspheres

    Science.gov (United States)

    Bai, X. F.; Li, J. S.; Wu, W.

    2017-02-01

    The porous CdIn2S4 microspheres were synthesized via a sodium dodecyl sulfate (SDS)-assisted hydrothermal technology. The as-prepared CdIn2S4 products were characterized by X-ray diffraction, field emission scanning electron microscopy and UV-Vis diffusive reflectance spectroscopy. The results showed that hydrothermal time and the surfactant addition had great effect on the structure, morphology and optical property of CdIn2S4 products.

  9. Hydrothermal Synthesis of Mesoporous Nanocrystalline Tetragonal ZrO2 Using Dehydroabietyltrimethyl Ammonium Bromine

    Directory of Open Access Journals (Sweden)

    Peng Wang

    2015-01-01

    Full Text Available Mesoporous nanocrystalline tetragonal zirconias were successfully synthesized through a hydrothermal method using a novel bioresource-derived quaternary ammonium salt, dehydroabietyltrimethyl ammonium bromine (DTAB, as a templating agent. The templating agent provides a surface area (242.02 m2/g, high pore volume (0.53 cm3/g, and large average pore diameter (7.65 nm, which suggests that DTAB is a good candidate for mesostructure synthesis. The hydrothermal treatments give the materials improved thermal stabilities because of the generation of tetragonal nanocrystallites that are more stable than the bulk amorphous ones in the hydrothermal process. However, because of the absence of stabilizers, the sizes of the crystallites of the as-synthesized sample increase gradually with increasing calcination temperature. As the crystalline size of the sample rises to 25 nm, the nanocrystallites become too large to integrate well together, causing the well-organized mesostructure to collapse.

  10. One-pot hydrothermal synthesis of Nitrogen-doped graphene as high-performance anode materials for lithium ion batteries

    Science.gov (United States)

    Xing, Zheng; Ju, Zhicheng; Zhao, Yulong; Wan, Jialu; Zhu, Yabo; Qiang, Yinghuai; Qian, Yitai

    2016-01-01

    Nitrogen-doped (N-doped) graphene has been prepared by a simple one-step hydrothermal approach using hexamethylenetetramine (HMTA) as single carbon and nitrogen source. In this hydrothermal process, HMTA pyrolyzes at high temperature and the N-doped graphene subsequently self-assembles on the surface of MgO particles (formed by the Mg powder reacting with H2O) during which graphene synthesis and nitrogen doping are simultaneously achieved. The as-synthesized graphene with incorporation of nitrogen groups possesses unique structure including thin layer thickness, high surface area, mesopores and vacancies. These structural features and their synergistic effects could not only improve ions and electrons transportation with nanometer-scale diffusion distances but also promote the penetration of electrolyte. The N-doped graphene exhibits high reversible capacity, superior rate capability as well as long-term cycling stability, which demonstrate that the N-doped graphene with great potential to be an efficient electrode material. The experimental results provide a new hydrothermal route to synthesize N-doped graphene with potential application for advanced energy storage, as well as useful information to design new graphene materials. PMID:27184859

  11. One-pot hydrothermal synthesis of Nitrogen-doped graphene as high-performance anode materials for lithium ion batteries

    Science.gov (United States)

    Xing, Zheng; Ju, Zhicheng; Zhao, Yulong; Wan, Jialu; Zhu, Yabo; Qiang, Yinghuai; Qian, Yitai

    2016-05-01

    Nitrogen-doped (N-doped) graphene has been prepared by a simple one-step hydrothermal approach using hexamethylenetetramine (HMTA) as single carbon and nitrogen source. In this hydrothermal process, HMTA pyrolyzes at high temperature and the N-doped graphene subsequently self-assembles on the surface of MgO particles (formed by the Mg powder reacting with H2O) during which graphene synthesis and nitrogen doping are simultaneously achieved. The as-synthesized graphene with incorporation of nitrogen groups possesses unique structure including thin layer thickness, high surface area, mesopores and vacancies. These structural features and their synergistic effects could not only improve ions and electrons transportation with nanometer-scale diffusion distances but also promote the penetration of electrolyte. The N-doped graphene exhibits high reversible capacity, superior rate capability as well as long-term cycling stability, which demonstrate that the N-doped graphene with great potential to be an efficient electrode material. The experimental results provide a new hydrothermal route to synthesize N-doped graphene with potential application for advanced energy storage, as well as useful information to design new graphene materials.

  12. Microwave radiation hydrothermal synthesis and characterization of micro- and mesoporous composite molecular sieve Y/SBA-15

    Directory of Open Access Journals (Sweden)

    Wenyuan Wu

    2017-05-01

    Full Text Available A microwave radiation hydrothermal method to control synthesis of micro- and mesoporous Y/SBA-15 composite molecular sieves was reported. The synthesized SBA-15 and Y/SBA-15 were characterized by scanning electron microscopy (SEM and N2 adsorption–desorption. The three kinds of different concentrations of hydrochloric acid (0.75 M, 2 M and 3.25 M were used to investigate the effect on Y/SBA-15. The analysis results of the composite products indicated that the optimization synthesis condition employed zeolite type Y and TEOS as silicon sources under 0.75 M hydrochloric acid by the microwave radiation hydrothermal synthesis method. The N2 adsorption–desorption test results of micro–mesoporous composite molecular sieve type Y/SBA-15 in mesoporous extent indicated that SBET is 355.529 m2/g, D‾BET is 4.050 nm, and mesoporous aperture focuses on the distribution region of 5.3 nm. It was found that the received composite product has an appropriate proportion of smaller size, larger size pore structure and the thicker pore wall. In addition, its internal channels have a high degree of order and smooth flow in long-range channels.

  13. Surfactant Assisted Hydrothermal Synthesis of CdSe Nanostructural Materials

    Institute of Scientific and Technical Information of China (English)

    Ganganagappa Nagaraju; Cujjarahalli Thimmanna Chandrappa

    2012-01-01

    CdSe/CTAB composite nanostructural materials were successfully synthesized at 160-200℃ for 2 days through a facile surfactant (cetyl trimethyl ammonium bromide-CTAB) assisted hydrothermal method us- ing cadmium acetate and sodium selenate as precursor. The obtained products were characterized by X-ray diffraction, energy dispersive X-ray analysis, Fourier transform infrared spectroscopy and thermo gravimetric analysis. Optical properties were studied by photoluminescence and UV-visible spectroscopy and morphology was investigated by scanning electron microscopy.

  14. Hydrothermal Synthesis and Structure of [{Mo8V4O36 (VO4) (VO)2 }n]7n-Bi-capped α-Keggin Fragments Linked to a Chain

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The title compound, (H2en) 3H3O { MosV4O36 (VO4) (VO) 2 } · 4H2O, was hydrothermally synthesized and structurally characterized by means of IR, ESR spectrum and single crystal X-ray diffraction. It crystallized in a monoclinic system with space group P21/c, a= 1. 980 4(4)nm, b=2. 063 4(4) nm, c=1. 192 0(2) nm, β=94. 76(3)°and deep black colour. The compound contains V-centered bi-capped a-Keggin fragments { MosV7O42 } that are linked together by edge-shared units V ⅣO5 via V-O-V bonds, forming a chain.

  15. Some peculiarities of zirconium tungstate synthesis by thermal decomposition of hydrothermal precursors

    Energy Technology Data Exchange (ETDEWEB)

    Gubanov, Alexander I., E-mail: gubanov@niic.nsc.su [Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, Akad. Lavrentiev Prospekt 3, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, Pirogova str. 2, 630090 Novosibirsk (Russian Federation); Dedova, Elena S. [Institute of Strength Physics and Materials Science, Siberian Branch of the Russian Academy of Sciences, pr. Akademicheskii 2/4, 634021 Tomsk (Russian Federation); Tomsk Polytechnic University, Lenin Avenue 30, 634050 Tomsk (Russian Federation); Plyusnin, Pavel E.; Filatov, Eugeny Y. [Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, Akad. Lavrentiev Prospekt 3, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, Pirogova str. 2, 630090 Novosibirsk (Russian Federation); Kardash, Tatyana Y. [Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, Akad. Lavrentiev Prospekt 5, 630090 Novosibirsk (Russian Federation); Korenev, Sergey V. [Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, Akad. Lavrentiev Prospekt 3, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, Pirogova str. 2, 630090 Novosibirsk (Russian Federation); Kulkov, Sergey N. [Institute of Strength Physics and Materials Science, Siberian Branch of the Russian Academy of Sciences, pr. Akademicheskii 2/4, 634021 Tomsk (Russian Federation); Tomsk Polytechnic University, Lenin Avenue 30, 634050 Tomsk (Russian Federation)

    2014-12-10

    Highlights: • Synthesis of ZrW{sub 2}O{sub 8} using hydrothermal method. • On hydrothermal synthesis optimal conc. of HCl in the reaction mixture is 2.3 M. • Thermal decomposition of ZrW{sub 2}O{sub 7}((OH){sub 1.5},Cl{sub 0.5})·2H{sub 2}O begins are 200 °S. • Amorphous intermediate crystallizes into cubic single-phase ZrW{sub 2}O{sub 8} above 550 °S. • ZrW{sub 2}O{sub 8} destructed at temperatures above 700 °S. - Abstract: This article discusses some peculiarities of the synthesis of ZrW{sub 2}O{sub 8} (1) using thermal decomposition of the precursor ZrW{sub 2}O{sub 7}((OH){sub 1.5},Cl{sub 0.5})·2H{sub 2}O (2) prepared by hydrothermal method. On hydrothermal synthesis of 2 the optimal concentration of hydrochloric acid in the reaction mixture is about 2.3 M. TG approach to determine the chemical composition of the precursor was suggested. It has been found that the precursor for the synthesis of zirconium tungstate has chemical formula 2. Thermal decomposition of the precursor 2 begins at 200 °S and affords an amorphous intermediate, which crystallizes as a cubic phase 1 above 550 °S with an exoeffect. The temperature of the beginning of the transition from amorphous to the crystalline state is 350 ± 25 °S.

  16. Distribution, structure and temporal variability of hydrothermal outflow at a slow-spreading hydrothermal field from seafloor image mosaics.

    Science.gov (United States)

    Barreyre, Thibaut; Escartin, Javier; Cannat, Mathilde; Garcia, Rafael; Science Party, Momar'08; Science Party, Bathyluck'09

    2010-05-01

    The Lucky Strike hydrothermal site, located South of the Azores along the Mid-Atlantic Ridge, is one of the largest and best-known active hydrothermal fields along the ridge system. This site within the MoMAR area is also the target for the installation in 2010 of a pilot deep-sea observatory with direct telemetry to land, to be part of the European Seafloor Observatory Network (ESONET). The Lucky Strike hydrothermal site has seen extensive high-resolution, near-bottom geophysical surveys in 1996 (Lustre'96), 2006 (Momareto06), 2008 (MOMAR08) and 2009 (Bathyluck09). Vertically acquired black-and-white electronic still camera images have been projected and georeferenced to obtain 3 image mosaics covering the zone of active venting, extending ~ 700x800 m2, and with full image resolution (~10 mm pixels). These data allow us to study how hydrothermal outflow is structured, including the relationships between the zones of active high-temperature venting, areas of diffuse outflow, and the geological structure (nature of the substrate, faults and fissures, sediments, etc.). Hydrothermal outflow is systematically associated with bacterial mats that are easily identified in the imagery, allowing us to study temporal variability at two different scales. Over the 13-year period we can potentially track changes in both the geometry and intensity of hydrothermal activity throughout the system; our preliminary study of the Eiffel Tower, White Castle and Mt Segur indicate that activity has been sustained in recent times, with small changes in the detailed geometry of the diffuse outflow and its intensity. At longer times scales (hundreds to 1000 years?) imagery also shows evidence of areas of venting that are no longer active, often associated with the active structures. In combination with the high-resolution bathymetry, the imagery data thus allow us to characterize the shallow structure of hydrothermal outflow at depth, the structural and volcanic control, and ultimately

  17. Hydrothermal synthesis of hydroxyapatite nanorods using pyridoxal-5′-phosphate as a phosphorus source

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Xin-Yu; Zhu, Ying-Jie, E-mail: y.j.zhu@mail.sic.ac.cn; Lu, Bing-Qiang; Chen, Feng; Qi, Chao; Zhao, Jing; Wu, Jin

    2014-07-01

    Graphical abstract: Hydroxyapatite nanorods are synthesized using biocompatible biomolecule pyridoxal-5′-phosphate as a new organic phosphorus source by the hydrothermal method. - Highlights: • Hydrothermal synthesis of hydroxyapatite nanorods is reported. • Biocompatible pyridoxal-5′-phosphate is used as an organic phosphorus source. • This method is simple, surfactant-free and environmentally friendly. - Abstract: Hydroxyapatite nanorods are synthesized by the hydrothermal method using biocompatible biomolecule pyridoxal-5′-phosphate (PLP) as a new organic phosphorus source. In this method, PLP biomolecules are hydrolyzed to produce phosphate ions under hydrothermal conditions, and these phosphate ions react with pre-existing calcium ions to form hydroxyapatite nanorods. The effects of experimental conditions including hydrothermal temperature and time on the morphology and crystal phase of the products are investigated. This method is simple, surfactant-free and environmentally friendly. The products are characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric (TG) analysis.

  18. High-throughput continuous hydrothermal synthesis of an entire nanoceramic phase diagram.

    Science.gov (United States)

    Weng, Xiaole; Cockcroft, Jeremy K; Hyett, Geoffrey; Vickers, Martin; Boldrin, Paul; Tang, Chiu C; Thompson, Stephen P; Parker, Julia E; Knowles, Jonathan C; Rehman, Ihtesham; Parkin, Ivan; Evans, Julian R G; Darr, Jawwad A

    2009-01-01

    A novel High-Throughput Continuous Hydrothermal (HiTCH) flow synthesis reactor was used to make directly and rapidly a 66-sample nanoparticle library (entire phase diagram) of nanocrystalline Ce(x)Zr(y)Y(z)O(2-delta) in less than 12 h. High resolution PXRD data were obtained for the entire heat-treated library (at 1000 degrees C/1 h) in less than a day using the new robotic beamline I11, located at Diamond Light Source (DLS). This allowed Rietveld-quality powder X-ray diffraction (PXRD) data collection of the entire 66-sample library in <1 day. Consequently, the authors rapidly mapped out phase behavior and sintering behaviors for the entire library. Out of the entire 66-sample heat-treated library, the PXRD data suggests that 43 possess the fluorite structure, of which 30 (out of 36) are ternary compositions. The speed, quantity and quality of data obtained by our new approach, offers an exciting new development which will allow structure-property relationships to be accessed for nanoceramics in much shorter time periods.

  19. High-temperature synthesis of highly hydrothermal stable mesoporous silica and Fe-SiO 2 using ionic liquid as a template

    Science.gov (United States)

    Liu, Hong; Wang, Mengyang; Hu, Hongjiu; Liang, Yuguang; Wang, Yong; Cao, Weiran; Wang, Xiaohong

    2011-03-01

    Mesoporous silicas and Fe-SiO 2 with worm-like structures have been synthesized using a room temperature ionic liquid, 1-hexadecane-3-methylimidazolium bromide, as a template at a high aging temperature (150-190 °C) with the assistance of NaF. The hydrothermal stability of mesoporous silica was effectively improved by increasing the aging temperature and adding NaF to the synthesis gel. High hydrothermally stable mesoporous silica was obtained after being aged at 190 °C in the presence of NaF, which endured the hydrothermal treatment in boiling water at least for 10 d or steam treatment at 600 °C for 6 h. The ultra hydrothermal stability could be attributed to its high degree of polymerization of silicate. Furthermore, highly hydrothermal stable mesoporous Fe-SiO 2 has been synthesized, which still remained its mesostructure after being hydrothermally treated at 100 °C for 12 d or steam-treated at 600 °C for 6 h.

  20. Hydrothermal and Solvothermal Synthesis of the Complex Fluoride α′-SrAIF5

    Institute of Scientific and Technical Information of China (English)

    贾志宏; 华瑞年; 石春山

    2003-01-01

    The complex fluoride α′-SrAlF5 has been synthesized through hydrothermal and solvothermal methods under mild conditions.The effects of the molar ratio of starting materials,temperature,reaction time and solvents on the synthesis of α′-SrAlF5 were discussed.The final products were characterized by XRD and SEM.The rod-like shape of α′-SrAlF5 is shown in SEM images.

  1. Hydrothermal synthesis and dielectric properties of lanthanum titanate ceramics

    Institute of Scientific and Technical Information of China (English)

    DENG Yuan; NAN Ce-wen

    2005-01-01

    Lanthanum titanate (La2/3TiO3) powders were synthesized by hydrothermal method based on the reaction of TiO2, La(NO3 )3 and KOH at 160 ℃ for 24 h followed by the treatment of acidification. The microstructure,morphology and dielectric properties were investigated by using X-ray diffraction, scanning electron microscope,transmission electron microscope and impedance method. The results show that the La2/3 TiO3 particles consist of nearly homogenous and lamellar grains. The particles can be sintered into porous ceramics above 1 150 ℃. The dielectric properties of La2/3 TiO3 show that both the dielectric constant and the dielectric loss tangent decrease with the increase of frequency.

  2. Facile hydrothermal synthesis of CeO2 nanopebbles

    Indian Academy of Sciences (India)

    N Sabari Arul; D Mangalaraj; Jeong In Han

    2015-09-01

    Cerium oxide (CeO2) nanopebbles have been synthesized using a facile hydrothermal method. X-ray diffraction pattern (XRD) and transmission electron microscopy analyses confirm the presence of CeO2 nanopebbles. XRD shows the formation of cubic fluorite CeO2 and the average particle size estimated from the Scherrer formula was found to be 6.69 nm. X-ray absorption spectrum of CeO2 nanopebbles exhibits two main sharp white lines at 880 and 898 eV due to the spin orbital splitting of 4 and 5. Optical absorption for the synthesized CeO2 nanopebbles exhibited a blue shift (g = 3.35 eV) with respect to the bulk CeO2 (g = 3.19 eV), indicating the existence of quantum confinement effects.

  3. Hydrothermal Synthesis and Crystal Structure of Iron Molybdophosphate Fe[Mo6O 12(OH)3(H2PO4)(HPO4)2(PO4)]2[Fe(2,2′-bipy)(H2O)2]2[Fe(2,2′-bipy)3]2·6H2O

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A molybdenum(V) phosphate supported by iron coordination complexes, Fe[Mo6-dine) 1, has been synthesized by hydrothermal synthesis and characterized. The title complex crystallizes in the monoclinic system, space group P21/c with a = 14.0005(8), b = 25.5229(12), c =17.9956(9) (A), β = 103.470(2)°, V = 6253.5(6) (A)3, Z = 2, Mr = 4114.03, Dc = 2.185 g/cm3, F(000) =4040,μ = 1.931 mm-1, R = 0.0438 and wR = 0.1168. The structure of the title polyoxometalate anion is based on a centrosymmetrical cluster Fe[Mo6O12(OH)3(H2PO4)(HPO4)2(PO4)]2 supported by two [Fe(2,2′-bipy)(H2O)2] subunits. The 2D network is formed through intermolecular hydrogen bonds.

  4. Hydrothermal Synthesis, Crystal Structure and Magnetic Properties of a Novel Zero-dimensional Manganese(Ⅱ) Complex with 2,2'-Diphenic Acid and 1,10-Phenanthroline Ligands

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A novel metal-organic coordination polymer [Mn3(2,2'-dipha)3(phen)6]n·3nH2O (2,2'-dipha = 2,2'-diphenic acid, phen = 1,10-phenanthroline) 1 has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction, elemental analyses, IR spectroscopy, and magnetic susceptibility measurements. The crystal crystallizes in triclinic, space group P1- with a = 16.921(5), b = 18.307(5), c = 18.450(5) (A), α = 113.369(5), β = 108.529(5), γ = 102.984(5)° , V = 4553(2) (A)3, C114H72Mn13N12O14.25, Mr = 2002.66, Dc = 1.461 g/cm3, λ(MoKα)= 0.488 mm-1, the final F(000) = 2058, Z = 2, R = 0.0491 and wR = 0.0980 for 9087 observed reflections (Ⅰ>2σ(Ⅰ)). In the crystal structure, the manganese atom is six-coordinated with two carboxylate oxygen atoms from different carboxylate groups of the same dipha and four nitrogen atoms from two different phen ligands, showing a slightly distorted octahedral geometry. Furthermore, it exhibits a zero-dimensional structure with dipha-Mn-phen- as building units. Variable-temperature magnetic measure shows an overall anti-ferromagnetic behavior for compound 1.

  5. Hydrothermal synthesis and crystal structure analysis of two new cadmium bismuthates, CdBi2O6 and Cd0.37Bi0.63O1.79

    Directory of Open Access Journals (Sweden)

    N. Kumada

    2015-09-01

    Full Text Available Two new cadmium bismuthates, CdBi2O6 and Cd0.37Bi0.63O1.79, were prepared by hydrothermal reaction using NaBiO3·nH2O as one of the starting compounds. The crystal structures of these compounds were refined by using synchrotron X-ray powder diffraction data. The former bismuthate has a MnSb2O6-type structure with a hexagonal cell (space group: P321; the cell parameters were a = 9.3641(7 and c = 4.9523(3 Å, and the final R-factors were Rwp = 4.59% and Rp = 3.04%. The latter bismuthate has a fluorite-type structure with a cubic cell (space group: Fm3¯m of a = 5.4110(4 Å, and the final R-factors were Rwp = 4.79% and Rp = 3.57%. These new bismuthates exhibit no photocatalytic activity under visible light.

  6. Hydrothermal Synthesis, Crystal Structures and Photoluminescence of Two Novel Metal-organic Supramolecular Frameworks Based on Mixed Ligands of Dipyrazino[2,3f:2'3'-h]quinoxaline and Pyridine-2,5-dicarboxylic Acid

    Institute of Scientific and Technical Information of China (English)

    WANG Xiu-Li; LIU Guo-Cheng; LIN Hong-Yan; CHEN Bao-Kuan; FANG Jia-Ni; ZHAO Hai-Yan

    2008-01-01

    Two novel metal-organic frameworks [Zn2(DlXl)2(2,5-pda)2(H2O)2]·2H2O (1) (dipyrazino[2,3f2'3'-h]quinoxaline=Dpq) and [Cd2(Dpq)2(2,5-pda)2]·2H2O (2) (pyridine-2,5-dicarboxylic acid=2,5-H2pda) have been obtained from hydrothermal reactions of two different metal(II) nitrates with the same mixed ligands Dpq and 2,5-H2pda,and structurally characterized by elemental analyses,TG,IR spectroscopy,and single-crystal X-ray diffraction analyse.Single-crystal X-ray analyses show that the metal ions are bridged by different coordination modes of 2,5-pda to form a dimer in 1,2D rhombic grid in 2,respectively.In the compound 1,adjacent dimers are packed through hydrogen bonds and π-π aromatic stacking interactions to form a distorted a-Po supramolecular structure.In the compound 2,adjacent polymer layers are further linked by hydrogen bonds to form a distorted a-Po 3D supramolecular framework stabilized by π-π stacking interactions.The different structures of compounds 1 and 2 illustrate the influence of the metal ions and ligands on the self-assembly of polymeric coordination architectures.In addition,the title compounds exhibit blue emission in the solid state at room temperature.

  7. Hydrothermal Synthesis and Responsive Characteristics of Hierarchical Zinc Oxide Nanoflowers to Sulfur Dioxide

    Directory of Open Access Journals (Sweden)

    Qu Zhou

    2016-01-01

    Full Text Available Sulfur dioxide, SO2, is one of the most important decomposition byproducts of sulfur hexafluoride, SF6, under partial discharge in GIS apparatus. The sensing performances of semiconductor gas sensors can be improved by morphology tailoring. This paper reported the synthesis method, structural characterization, and SO2 responsive characteristics of hierarchical flower-shaped ZnO nanostructures. Hierarchical ZnO nanoflowers were successfully prepared via a facile and simple hydrothermal method and characterized by X-ray powder diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy, respectively. Planar chemical gas sensor was fabricated and its responsive characteristics towards SO2 were systematically performed. The optimum operating temperature of the fabricated sensor was measured to be about 260°C, and the corresponding maximum responses were 16.72 and 26.14 to 30 and 60 ppm of SO2. Its saturated gas concentration was 2000 ppm with a response value of 67.41. Moreover, a quick response and recovery feature (7 s and 8 s versus 80 ppm of SO2 and good stability were also observed. All results indicate that the proposed sensor is a promising candidate for detecting SF6 decomposition byproduct SO2.

  8. Improved seedless hydrothermal synthesis of dense and ultralong ZnO nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Tian Jinghua; Hu Jie; Li Sisi; Zhang Fan; Liu Jun; Shi Jian; Li Xin; Chen Yong [Ecole Normale Superieure, CNRS-ENS-UPMC UMR 8640, 24 rue Lhomond, 75005 Paris (France); Tian Zhongqun, E-mail: yong.chen@ens.fr [State Key Laboratory of Physical Chemistry of Solid Surfaces and LIA CNRS XiamENS ' NanoBioChem' , College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian (China)

    2011-06-17

    Seedless hydrothermal synthesis has been improved by introducing an adequate content of ammonia into the nutrient solution, allowing the fabrication of dense and ultralong ZnO nanowire arrays over large areas on a substrate. The presence of ammonia in the nutrient solution facilitates the high density nucleation of ZnO on the substrate which is critical for the nanowire growth. In order to achieve an optimal growth, the growth conditions have been studied systematically as a function of ammonia content, growth temperature and incubation time. The effect of polyethyleneimine (PEI) has also been studied but shown to be of no benefit to the nucleation of ZnO. Ultradense and ultralong ZnO nanowires could be obtained under optimal growth conditions, showing no fused structure at the foot of the nanowire arrays. Due to different reaction kinetics, four growth regimes could be attributed, including the first fast growth, equilibrium phase, second fast growth and final erosion. Combining this simple method with optical lithography, ZnO nanowires could be grown selectively on patterned areas. In addition, the as-grown ZnO nanowires could be used for the fabrication of a piezoelectric nanogenerator. Compared to the device of ZnO nanowires made by other methods, a more than twice voltage output has been obtained, thereby proving an improved performance of our growth method.

  9. Synthesis of high saturation magnetic iron oxide nanomaterials via low temperature hydrothermal method

    Science.gov (United States)

    Bhavani, P.; Rajababu, C. H.; Arif, M. D.; Reddy, I. Venkata Subba; Reddy, N. Ramamanohar

    2017-03-01

    Iron oxide nanoparticles (IONPs) were synthesized through a simple low temperature hydrothermal approach to obtain with high saturation magnetization properties. Two series of iron precursors (sulfates and chlorides) were used in synthesis process by varying the reaction temperature at a constant pH. The X-ray diffraction pattern indicates the inverse spinel structure of the synthesized IONPs. The Field emission scanning electron microscopy and high resolution transmission electron microscopy studies revealed that the particles prepared using iron sulfate were consisting a mixer of spherical (16-40 nm) and rod (diameter 20-25 nm, length distributed spherical shapes with size range 5-20 nm. On other hand, the IONPs synthesized at reaction temperature of 190 °C has spherical (16-46 nm) morphology in both series. The band gap values of IONPs were calculated from the obtained optical absorption spectra of the samples. The IONPs synthesized using iron sulfate at temperature of 130 °C exhibited high saturation magnetization (MS) of 103.017 emu/g and low remanant magnetization (Mr) of 0.22 emu/g with coercivity (Hc) of 70.9 Oe, which may be attributed to the smaller magnetic domains (dm) and dead magnetic layer thickness (t).

  10. HYDROTHERMAL MEDIATED SYNTHESIS OF ZnO NANORODS AND THEIR ANTIBACTERIAL PROPERTIES

    Directory of Open Access Journals (Sweden)

    R. S. Subhasree

    2012-03-01

    Full Text Available Nanoceramics which possess antibacterial activity have recently received much attention as new inorganic antibacterial materials. Herein, we report the synthesis of nanostructured zinc oxide (ZnO by surfactant assisted hydrothermal route using zinc acetate and hexamethylenetetramine (HMT. The as prepared ZnO nanoparticles were characterized by Fourier transform infrared spectroscopy (FT-IR, Ultraviolet- visible spectroscopy (UV-Vis, Photoluminescence spectroscopy, X-ray diffraction (XRD and Field emission- scanning electron microscopy (FE-SEM. The XRD diffraction pattern corresponds to wurtzite structure of ZnO (JCPDS No.36:1451. The average crystallite size of the nanoparticles calculated from XRD, using Scherrer’s equation, is approximately 10 nm. FE-SEM shows the as prepared ZnO are in the form of hexagonal nanorods. The antibacterial behavior of suspension of ZnO nanorods against Escherichia coli (Gram-negative and Staphylococcus aureus (Gram-positive showed an enhanced antibacterial activity as compared to the bulk ZnO.

  11. Hydrothermal descriptive chemistry and single crystal structure determination of cesium and rubidium thorium fluorides.

    Science.gov (United States)

    Underwood, Christopher C; Mann, Matthew; McMillen, Colin D; Kolis, Joseph W

    2011-11-21

    Two new cesium thorium fluorides and three new rubidium thorium fluorides have been synthesized hydrothermally and structurally characterized. The structures of two polymorphs of CsTh(3)F(13) are described in space group P6/mmm with a = 8.2608(14) and c = 8.6519(17) and space group Pmc2(1) with a = 8.1830(16), b = 7.5780(15), and c = 8.6244(17). The analogous orthorhombic compound RbTh(3)F(13), with a = 8.1805(16), b = 7.4378(15), and c = 8.6594(17) in space group Pmc2(1), is also reported. Two other rubidium thorium fluorides are also described: RbTh(2)F(9) crystallizes in the space group Pnma where a = 8.9101(18), b = 11.829(2), and c = 7.4048(15), and Rb(7)Th(6)F(31) crystallizes in the space group R3 where a = 15.609(2) and c = 10.823(2). Comparison of these materials was made on the basis of their structures and synthesis conditions. The formation of these species in hydrothermal fluids appears to be dependent upon the concentration of the alkali fluoride mineralizer solution and, thus, the ratio of alkali ions to thorium in the system.

  12. Hydrothermal synthesis and characterizations of Ti substituted Mn-ferrites

    Energy Technology Data Exchange (ETDEWEB)

    Mostafa, Nasser Y., E-mail: nmost69@yahoo.com [Faculty of Science, Taif University, P.O. Box 888 Al-Haweiah, Taif (Saudi Arabia); Chemistry Department, Faculty of Science, Suez Canal University, Ismailia 41522 (Egypt); Hessien, M.M. [Faculty of Science, Taif University, P.O. Box 888 Al-Haweiah, Taif (Saudi Arabia); Advanced materials Division-Central metallurgical R and D Institute (CMRDI), P.O. Box 87 Helwan, Cairo (Egypt); Shaltout, Abdallah A. [Faculty of Science, Taif University, P.O. Box 888 Al-Haweiah, Taif (Saudi Arabia); Spectroscopy Department, Physics Division, National Research Center, El Behooth Str., 12622 Dokki, Cairo (Egypt)

    2012-07-15

    Highlights: Black-Right-Pointing-Pointer Hydrothermal synthesized of well-crystallized Ti-substituted MnFe{sub 2}O{sub 4} nanoparticles at 180 Degree-Sign C without any calcination step. The chemical composition was represented by Mn{sub 1-2x}Ti{sub x}Fe{sub 2}O{sub 4} with x having values 0.0, 0.1, 0.2, 0.3 and 0.4. Black-Right-Pointing-Pointer The change in lattice parameter and saturation magnetization with increasing Ti-substitution was investigated and explained. Black-Right-Pointing-Pointer The change in microstructure due to Ti{sup 4+} ions substitutions was investigated using TEM analysis. - Abstarct: A series of well-crystallized Mn{sub 1-2x}Ti{sub x}Fe{sub 2}O{sub 4} nanoparticles with x values of 0.0, 0.1, 0.2, 0.3 and 0.4 have been synthesized by hydrothermal route at 180 Degree-Sign C in the presence of NaOH as mineralizer. The obtained ferrite samples were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and vibrating sample magnetometer (VSM). The XRD analysis showed that pure single phases of cubic ferrites were obtained with x up to 0.2. However, samples with x > 0.2 showed traces of unreacted anatase. The increase in Ti-substitution up to x = 0.2 leads to an increase in the lattice parameter of the prepared ferrites. On the other hand, the increase in Ti-substitution over x = 0.2 leads to a decrease in the lattice parameter. The average crystallite size was in the range of 39-57 nm, where it is increased by increasing the Ti-substitution up to x = 0.3, then decreased for x = 0.4. According to VSM results, the saturation magnetization increased with Ti ion substitution of x = 0.1 and decreased for x > 0.1.

  13. Hydrothermal Synthesis and Structure of a Novel Molybdenum Phosphate: Na4(H3O) [Na(HPO4)2(PO4)4Mo18O49]·16H2O①

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The title compound Na5H37P6Mo18O90 1 (Mr=1658) was synthesized under hydrothermal condition and its crystal structure was determined by X-ray diffraction. It crystallized in the monoclinic system, space group P21 with a =14.957(1), b =16.535(1), c = 16.159(1)?,β=108.586(2)°, V=3787.85?3, Dc =3.040g/cm3, Z=2,μ(MoKα)=3.17mm-1, F(000)=3242. The final R and wR are 0.0500 and 0.1535 for 6643 observable reflections with I≥2σ(I), respectively. The result of structure analysis indicates that [Na(HPO4)2(PO4)4-Mo18 O49]5-anions 2 in 1 has the symmetry of C2V, in which each MoVIO6 octahedron is connected to adjacent PO4 tetrahedra through corner-sharing and to adjacent octahedra through edge-sharing or corner-sharing.

  14. Hydrothermal Synthesis and Structure of a Mixed-valence Polyoxotungstate Decorated by Copper(I) Coordination Group, [Cu(en)2H2O]2[{Cu(en)2}HPW12O40]·2H2O

    Institute of Scientific and Technical Information of China (English)

    LI Zhen; LIN Bi-Zhou; HAN Guo-Hua; GENG Feng; LIU Pei-De

    2005-01-01

    A complex [Cu(en)2H2O]2[{Cu(en)2}HPW12O40]·2H2O (C12H57Cu3N12O44PW12, Mr = 3501.49) has been synthesized under hydrothermal conditions and its crystal structure was determined by X-ray diffraction.It crystallizes in the orthorhombic system, space group Pbca with a = 21.680(4), b = 20.680(4), c = 26.120(5) (A), V = 11711(4) (A)3, Dc = 3.972 g/cm3, Z = 8, μ(MoKa) = 24.661 mm-1, F(000) = 12440, the final R = 0.0527 and wR = 0.1416 for 11527 observed reflec- tions with I > 2σ(I).The crystal structure is composed of [{Cu(en)2}HPW12O40]2- anions, discrete [Cu(en)2H2O]+ complex cations and crystal water molecules, which are held together into a three- dimensional network through hydrogen-bonding interactions.The anionic [{Cu(en)2}HPW12O40]2- is formed by the mixed valance {HPWVI11WVO40}3- Keggin unit covalently linked by a {Cu(en)2}+ group.

  15. Hydrothermal Synthesis and Crystal Structure of a Zinc Complex: [Zn2.5(phen)(BDC)2(OH)](phen = 1,10-Phenanthroline, BDC= Benzene-1,4-dicarboxylic Acid)

    Institute of Scientific and Technical Information of China (English)

    WANG Qing-Wei; LI Xiu-Mei; SHI Lin-Fang

    2008-01-01

    A metal-organic coordination polymer [Zn2.5(phen)(BDC)2(OH)]2 (phen = 1,10-phenanthroline, BDC = benzene-1,4-dicarboxylic acid)1 has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction, elemental analyses and IR spectro-scopy. The complex crystallizes in the triclinic system, space group P1 with a = 11.199(2), b =11.593(2), c = 11.865(3) A, α= 99.330(1), β=111.506(1),γ = 104.804(1)°, V= 1328.4(5) A3, Dc=1.722 g/cm3, Z = 1, Mr = 1377.82, F(000) = 692, μ(MoKa) = 2.306 mm-1, S = 1.093, R = 0.0281 and wR= 0.0756 for 4179 observed reflections (Ⅰ 20(Ⅰ)). The coordination polyhedron around Zn(Ⅱ)can be described as a tetrahedron, trigonal bipyramid and octahedron. It is worth noting that the crystal structure of 1 is composed of tetranuclear zinc clusters linked by {ZnO6} units.

  16. One-step hydrothermal synthesis of three-dimensional porous graphene aerogels/sulfur nanocrystals for lithium–sulfur batteries

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Yong; Lu, Mengna; Ling, Xuetao; Jiao, Zheng; Chen, Lingli; Chen, Lu [School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444 (China); Hu, Pengfei [Instrumental Analysis and Research Center, Shanghai University, Shanghai 200444 (China); Zhao, Bing, E-mail: bzhao@shu.edu.cn [School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444 (China)

    2015-10-05

    Highlights: • 3D porous GA/S nanocrystals are prepared by a one-step hydrothermal method. • The structure is affected by hydrothermal temperature and liquid sulfur’s viscosity. • The hybrid delivers a capacity of 716.2 mA h g{sup −1} after 50 cycles at 100 mA g{sup −1}. • The nanosized S, strong adsorbability and intimate contact of GNS are main factors. - Abstract: Lithium–sulfur (Li–S) batteries are receiving significant attention as a new energy source because of its high theoretical capacity and specific energy. However, the low sulfur loading and large particles (usually in submicron dimension) in the cathode greatly offset its advantage in high energy density and lead to the instability of the cathode and rapid capacity decay. Herein, we introduce a one-step hydrothermal synthesis of three-dimensional porous graphene aerogels/sulfur nanocrystals to suppress the rapid fading of sulfur electrode. It is found that the hydrothermal temperature and viscosity of liquid sulfur have significant effects on particle size and loading mass of sulfur nanocrystals, graphitization degree of graphene and chemical bonding between sulfur and oxygen-containing groups of graphene. The hybrid could deliver a specific capacity of 716.2 mA h g{sup −1} after 50 cycles at a current density of 100 mA g{sup −1} and reversible capacity of 517.9 mA h g{sup −1} at 1 A g{sup −1}. The performance we demonstrate herein suggests that Li–S battery may provide an opportunity for development of rechargeable battery systems.

  17. Hydrothermal Synthesis and Catalytic Application of Ultrathin Rhodium Nanosheet Nanoassemblies.

    Science.gov (United States)

    Bai, Juan; Xu, Guang-Rui; Xing, Shi-Hui; Zeng, Jing-Hui; Jiang, Jia-Xing; Chen, Yu

    2016-12-14

    Ultrathin noble metal nanosheets with atomic thickness exhibit abnormal electronic, surfacial, and photonic properties due to the unique two-dimensional (2D) confinement effect, which have attracted intensive research attention in catalysis/electrocatalysis. In this work, the well-defined ultrathin Rh nanosheet nanoassemblies with dendritic morphology are synthesized by a facile hydrothermal method with assistance of poly(allylamine hydrochloride) (PAH), where PAH effectively acts as the complexant and shape-directing agent. Transmission electron microscopy and atomic force microscopy images reveal the thickness of 2D Rh nanosheet with (111) planes is only ca. 0.8-1.1 nm. Nitrogen adsorption-desorption measurement displays the specific surface area of the as-prepared ultrathin Rh nanosheet nanoassemblies is 139.4 m(2) g(-1), which is much bigger than that of homemade Rh black (19.8 m(2) g(-1)). Detailed catalytic investigations display the as-prepared ultrathin Rh nanosheet nanoassemblies have nearly 20.4-fold enhancement in mass-activity for the hydrolysis of ammonia borane as compared with homemade Rh black.

  18. Hydrothermal synthesis of siderite nano-particles and characterizations

    Science.gov (United States)

    Oza, Mahatta; Joshi, M. J.

    2017-05-01

    Siderite is an iron ore in the form of ferrous carbonate (FeCO3). It finds applications in ceramics, in pig iron production, pigments in paints and in petroleum drilling fluids as a scavenger for H2S. An attempt was made to synthesize FeCO3 nano-particles by hydrothermal treatment of aqueous solution of iron sulphate, ascorbic acid, and ammonium carbonate with a molar ratio of 1:1:3, respectively, at 140˚C for 1.5 h. The synthesized powder was further characterized by different characterization techniques like powder XRD, FT-IR and TGA. The powder XRD analysis suggested the nano-crystalline nature of the sample with Hexagonal crystal system having unit cell parameters as: a = 4.691Ǻ, b = 4.691 Ǻ and c = 15.37Ǻ. The average crystallite size was found to be ̴ 10.70 nm from Scherrer's formula. FT-IR spectrum confirmed the presence of O-H, and C-O functional groups. The TGA results suggested that the material started decomposing from the beginning and showed weight loss of 32.4% at 358°C temperature. Thereafter, the sample very slowly decomposed and at the end of process sample showed weight loss of 39.5% at 900°C after giving up carbon dioxide.

  19. Hydrothermal synthesis and chromic properties of hexagonal WO3 nanowires

    Institute of Scientific and Technical Information of China (English)

    Yuan Hua-Jun; Chen Ya-Qi; Yu Fang; Peng Yue-Hua; He Xiong-Wu; Zhao Ding; Tang Dong-Sheng

    2011-01-01

    This paper reports that highly purified hexagonal WO3 nanowires are synthesized by a simple hydrothermal method. The as-synthesized WO3 nanowires are investigated in detail by ultraviolet-visible-near infrared spectroscopy and electrical transport measurements under different conditions. It finds that the optical band gap and the diffuse reflection coefficient in the wavelength region above 450 nm of WO3 nanowires decrease observably upon exposure to ultraviolet light or NH3 gas. It is also found that there are electrons being trapped or released in individual WO3 nanowires when scanning bias voltage in different directions upon exposure to ultraviolet and NH3 gas. The experimental results suggest that the chromic properties might be attributed to the injection/extraction of hydrogen ions induced by ultraviolet light irradiation in air or creation/annihilation of oxygen vacancies induced by NH3 gas exposure, which serve as colour centres and trap electrons as polarons. The experimental results also suggest that the hexagonal WO3 nanowires will be a good candidate for sensing reduced gas such as NH3.

  20. Mild Hydrothermal Synthesis of Ni–Cu Nanoparticles

    Directory of Open Access Journals (Sweden)

    G. H. Mohamed Saeed

    2010-01-01

    Full Text Available Magnetic Ni-rich Ni–Cu nanoparticles with Ni : Cu mass ratio (S of 2.0 and 2.6 were prepared using a mixture of polyoxyethylene (10 isooctylphenyl ether (Triton X-100 and sodium dodecyl sulfate (SDS in a mild hydrothermal condition at 95ºC. X-ray diffractometry (XRD showed that the nanoparticles prepared at S=2.0 possessed Ni–Cu alloy characteristic whereas the characteristic was absent at S=2.6. The XRD data was enhanced by Fourier transform infrared spectroscopy (FTIR which exhibited metal-metal (Ni–Cu band at 455 cm−1. Based on transmission electron microscopy (TEM, the average particle sizes for the nanoparticles prepared at S=2.0 and 2.6 were in the range of 19–23 nm. The as-prepared nanoparticles exhibited paramagnetic behaviour measured using a vibrating sample magnetometer (VSM and the specific saturation magnetization decreased at the higher concentration of Ni.

  1. Hydrothermal Synthesis of VO2 Polymorphs: Advantages, Challenges and Prospects for the Application of Energy Efficient Smart Windows.

    Science.gov (United States)

    Li, Ming; Magdassi, Shlomo; Gao, Yanfeng; Long, Yi

    2017-07-19

    Vanadium dioxide (VO2 ) is a widely studied inorganic phase change material, which has a reversible phase transition from semiconducting monoclinic to metallic rutile phase at a critical temperature of τc ≈ 68 °C. The abrupt decrease of infrared transmittance in the metallic phase makes VO2 a potential candidate for thermochromic energy efficient windows to cut down building energy consumption. However, there are three long-standing issues that hindered its application in energy efficient windows: high τc , low luminous transmittance (Tlum ), and undesirable solar modulation ability (ΔTsol ). Many approaches, including nano-thermochromism, porous films, biomimetic surface reconstruction, gridded structures, antireflective overcoatings, etc, have been proposed to tackle these issues. The first approach-nano-thermochromism-which is to integrate VO2 nanoparticles in a transparent matrix, outperforms the rest; while the thermochromic performance is determined by particle size, stoichiometry, and crystallinity. A hydrothermal method is the most common method to fabricate high-quality VO2 nanoparticles, and has its own advantages of large-scale synthesis and precise phase control of VO2 . This Review focuses on hydrothermal synthesis, physical properties of VO2 polymorphs, and their transformation to thermochromic VO2 (M), and discusses the advantages, challenges, and prospects of VO2 (M) in energy-efficient smart windows application. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. VentDB: A Global Online Synthesis Database of Seafloor Hydrothermal Spring Geochemistry

    Science.gov (United States)

    Mottl, M. J.; Lehnert, K. A.; Johansson, A. K.; Hsu, L.

    2011-12-01

    Chemical data for seafloor hydrothermal springs are fundamental to the study of mid-ocean ridge and seafloor processes, ocean water chemistry, and global geochemical cycles, as well as vent ecosystems and the sub-seafloor biosphere. So far, these data have been accessible only in the scientific literature or in online data catalogs where they are widely dispersed in individual data tables, and are often insufficiently documented for re-use. We have developed VentDB as an online data system for geochemical data for hydrothermal springs that will facilitate access and analysis of these data. VentDB uses the concept and architecture of the popular PetDB database for seafloor igneous and metamorphic rock geochemistry (www.petdb.org) to provide easy and fast access to a global synthesis of seafloor hydrothermal spring geochemical data. The VentDB database contains concentrations of major and trace species, dissolved gases, and radiogenic and isotopic ratios for hydrothermal vents on the seafloor. Further chemical or physical properties of hydrothermal springs can be included in the future if desired. The database comprises both the calculated hydrothermal end-member solution compositions as estimated by extrapolation of the concentrations of individual chemical species to a Mg concentration of zero, and the raw data for hydrothermal solution samples as collected, where available. Data quality is documented by including information for the raw analytical data about the analytical method, precision, and reference material measurements, and quality control parameters for end-member compositions including the lowest Mg measured in any sample, the number of samples and correlation coefficient of the linear regression, and the charge balance for the extrapolated zero-Mg composition. The database also includes information about the sampled locations (geospatial coordinates, vent or vent field names, names of other physiographic features), temperature, flow and vent type

  3. Hydrothermal Synthesis and Properties of Open-Framework Mixed-valence Iron Phosphates FeIII2FeII1.5(PO4)3 with Three-dimensional Structure

    Institute of Scientific and Technical Information of China (English)

    DUAN,Li-Ying(段丽颖); LIU,Fu-Chen(刘福臣); WANG,En-Bo(王恩波); LI,Yang-Guang(李阳光); HU,Chang-Wen(胡长文); XU,Lin(许林)

    2004-01-01

    The open-framework iron phosphate FeIII2FeII1.5(PO4)3 was hydrothermally synthesized and characterized by elemental analysis, IR, EPR, XPS and single crystal X-ray diffraction analysis. The title compound crystallized in the triclinic, space group P1 with a=0.64724(4) nm, b=0.79651(6) nm, c=0.94229(5) nm, α=104.447(2)°, β=108.919(4)°, γ=101.741(4)°, V=0.42302(5) nm3, Z=1 and R1 (wR2)=0.0307 (0.0793). Crystal data were collected on a Rigaku R-AXIS RAPID IP diffractometer with Mo Kα (λ=0.071073 nm) at 293(2) K in the range of 2.43°<θ<27.46°. The structure of 1 consists of 19 non-hydrogen atoms including three and a half crystallographically independent Fe and three P atoms. Fe(1) connects its symmetrical Fe(1A) through bridging oxygen forming a dimer and the dimers are connected by Fe(4) forming an infinite staircase-like chain. Fe(2) and Fe(3) connect the infinite chains into a layer with bridging oxygen. Layers are interconnected via Fe(4) forming the six-membered and eight-membered channel systems.

  4. Hydrothermal synthesis and structural characterization of a family of lanthanide tartrates: [Ln 2(C 4H 4O 6) 3(H 2O) 3]·1.5H 2O (Ln = La, Ce, Pr, Nd, Sm)

    Science.gov (United States)

    Athar, Muhammad; Li, Guanghua; Shi, Zhan; Chen, Yan; Feng, Shouhua

    2008-12-01

    Coordination polymers containing lanthanides with tartaric acid [Ln 2(C 4H 4O 6) 3(H 2O) 3]·1.5H 2O (Ln = La, Ce, Pr, Nd, Sm and C 4H 4O 6 = D(-) or L(+) tartrate anion) have been synthesized using hydrothermal techniques and characterized by single crystal X-ray diffraction. The compounds are all isotypic with a monoclinic crystal system in the P2 1/ n space group. The asymmetric units of coordination polymers contain two metal centers having different coordination environments. One metal is bonded to four tartrate groups having three D and one L isomers (or three L and one D isomers), whereas the other metal is bonded to five tartrate groups having two D and three L isomers (or two L and three D isomers). Each trivalent metal center is coordinated to nine oxygen atoms that originate from carboxylate and hydroxyl groups of the tartrate anions and water molecules. These new polymers have three-dimensional structures containing open channels that are occupied by non-coordinating water molecules. Thermogravimetric and differential thermal analyses and adsorption of nitrogen have also been studied for these compounds.

  5. Hydrothermal Synthesis and Crystal Structure of a Microporous Gallophosphate with 12-Membered Ring Channels:Ga9(PO4)12(H3TREN)(H2TREN)3·xH2O

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiao-bo; LI Yi; LI Guang-hua; DAI Zhi-min; FU Wen-sheng; SHI Zhan; ZHANG Dong; XU Yao-hua; FENG Shou-hua

    2004-01-01

    An open-framework gallophosphate, Ga9(PO4)12[(H3TREN)(H2TREN)3]·xH2O was hydrothermally synthesized at 453 K with tris(2-aminoethyl) amine(TREN) as the organic template and characterized by single-crystal X-ray diffraction. Ga9(PO4)12[(H3TREN)(H2TREN)3]·xH2O crystallized in a cubic space group I43m, with a=1.68552(3) nm and Z=2. The structure contains 12-membered ring channels and supercages of 1.434 nm in diameter, and is an analogue of Al9(PO4)12(C24H91N16)·17H2O. Template-TREN in the supercage was different from triethylenetetraamine(TETA) used in the initial reaction mixture due to the construction transformation. The TETAs transformed into the TRENs due to the low interaction energy between the template and framework. We verified it via energy calculation and liquid state NMR.

  6. Hydrothermal synthesis of alpha- and beta-HgS nanostructures

    Science.gov (United States)

    Galain, Isabel; María, Pérez Barthaburu; Ivana, Aguiar; Laura, Fornaro

    2017-01-01

    We synthesized HgS nanostructures by the hydrothermal method in order to use them as electron acceptors in hybrid organic-inorganic solar cells. We employed different mercury sources (HgO and Hg(CH3COO)2) and polyvinylpyrrolidone (PVP) or hexadecanethiol (HDT) as stabilizing/capping agent for controlling size, crystallinity, morphology and stability of the obtained nanostructures. We also used thiourea as sulfur source, and a temperature of 180 °C during 6 h. Synthesized nanostructures were characterized by powder X-Ray Diffraction, Diffuse Reflectance Infrared Fourier Transform and Transmission Electron Microscopy. When PVP acts as stabilizing agent, the mercury source has influence on the size -but not in morphology- of the beta-HgS obtained nansostructures. HDT has control over nanostructures' size and depending on the relation Hg:HDT, we obtained a mixture of alpha and beta HgS which can be advantageous in the application in solar cells, due their absorption in different spectral regions. The smallest nanostructures obtained have a mean diameter of 20 nm when using HDT as capping agent. Also, we deposited the aforementioned nanostructures onto flat glass substrates by the spin coating technique as a first approach of an active layer of a solar cell. The depositions were characterized by atomic force microscopy. We obtained smaller particle deposition and higher particle density -but a lower area coverage (5%) - in samples with HDT as capping agent. This work presents promising results on nanostructures for future application on hybrid solar cells. Further efforts will be focused on the deposition of organic-inorganic layers.

  7. Bismuth molybdate catalysts prepared by mild hydrothermal synthesis: Influence of pH on the selective oxidation of propylene

    DEFF Research Database (Denmark)

    Schuh, Kirsten; Kleist, Wolfgang; Høj, Martin

    2015-01-01

    A series of bismuth molybdate catalysts with relatively high surface area was prepared via mild hydrothermal synthesis. Variation of the pH value and Bi/Mo ratio during the synthesis allowed tuning of the crystalline Bi-Mo oxide phases, as determined by X-ray diffraction (XRD) and Raman spectrosc...

  8. Green Synthesis of Nanocrystalline Cu2ZnSnS4 Powder Using Hydrothermal Route

    Directory of Open Access Journals (Sweden)

    Shri kant Verma

    2013-01-01

    Full Text Available Nanocrystalline Cu2ZnSnS4 (CZTS powder was synthesized by a hydrothermal process, using thiourea as sulfur precursor. The powder was qualitatively analyzed using X-ray to identify the phase, and the size of the particles was determined using transmission electron microscopy (TEM. Raman peak at 337.5 cm−1 confirms the formation of pure CZTS particles. The powder was also synthesized solvothermally using ethylenediamine as solvent. The hydrothermally synthesized powder indicated the presence of the kesterite phase Cu2ZnSnS4 and particle size of about 4-5 nm. This environmentally green synthesis by hydrothermal route can produce gram scale synthesis of material with a chemical yield in excess of ~ 90%. UV Vis absorption spectra measurements indicated the band gap of as-synthesized CZTS nanoparticles to be 1.7 eV, which is near the optimum value for photovoltaic solar cell, showing its possible use in photovoltaics.

  9. Simple mass production of zinc oxide nanostructures via low-temperature hydrothermal synthesis

    Science.gov (United States)

    Ghasaban, Samaneh; Atai, Mohammad; Imani, Mohammad

    2017-03-01

    The specific properties of zinc oxide (ZnO) nanoparticles have attracted much attention within the scientific community as a useful material for biomedical applications. Hydrothermal synthesis is known as a useful method to produce nanostructures with certain particle size and morphology however, scaling up the reaction is still a challenging task. In this research, large scale hydrothermal synthesis of ZnO nanostructures (60 g) was performed in a 5 l stainless steel autoclave by reaction between anionic (ammonia or sodium hydroxide) and cationic (zinc acetate dehydrate) precursors in low temperature. Hydrothermal reaction temperature and time were decreased to 115 °C and 2 or 6 h. In batch repetitions, the same morphologies (plate- and needle-like) with reproducible particle size were obtained. The nanostructures formed were analyzed by powder x-ray diffraction, Fourier-transform infrared spectroscopy, energy dispersive x-ray analysis, scanning electron microscopy and BET analysis. The nanostructures formed were antibacterially active against Staphylococcus aureus.

  10. Sonochemical and hydrothermal synthesis of PbTe nanostructures with the aid of a novel capping agent

    Energy Technology Data Exchange (ETDEWEB)

    Fard-Fini, Shahla Ahmadian [Department of Chemistry, Payame Noor University, P.O. Box 19395-3697, Tehran, Islamic Republic of Iran (Iran, Islamic Republic of); Salavati-Niasari, Masoud, E-mail: salavati@kashanu.ac.ir [Department of Inorganic Chemistry, Faculty of Chemistry, University of Kashan, P.O. Box 87317-51167, Kashan, Islamic Republic of Iran (Iran, Islamic Republic of); Institute of Nano Science and Nano Technology, University of Kashan, P.O. Box 87317-51167, Kashan, Islamic Republic of Iran (Iran, Islamic Republic of); Mohandes, Fatemeh [Department of Inorganic Chemistry, Faculty of Chemistry, University of Kashan, P.O. Box 87317-51167, Kashan, Islamic Republic of Iran (Iran, Islamic Republic of)

    2013-10-15

    Graphical abstract: - Highlights: • PbTe nanostructures were prepared with the aid of Schiff-base compound. • Sonochemical and hydrothermal methods were employed to fabricate PbTe nanostrucrues. • The effect of preparation parameters on the morphology of PbTe was investigated. - Abstract: In this work, a new Schiff-base compound derived from 1,8-diamino-3,6-dioxaoctane and 2-hydroxy-1-naphthaldehyde marked as (2-HyNa)-(DaDo) was synthesized, characterized, and then used as capping agent for the preparation of PbTe nanostructures. To fabricate PbTe nanostructures, two different synthesis methods; hydrothermal and sonochemical routes, were applied. To further investigate, the effect of preparation parameters like reaction time and temperature in hydrothermal synthesis and sonication time in the presence of ultrasound irradiation on the morphology and purity of the final products was tested. The products were analyzed with the aid of SEM, TEM, XRD, FT-IR, and EDS. Based on the obtained results, it was found that pure cubic phased PbTe nanostructures have been obtained by hydrothermal and sonochemical approaches. Besides, SEM images showed that cubic-like and rod-like PbTe nanostructures have been formed by hydrothermal and sonochemical methods, respectively. Sonochemical synthesis of PbTe nanostructures was favorable, because the synthesis time of sonochemical method was shorter than that of hydrothermal method.

  11. Hydrothermal synthesis of Ce: LuzSiO5 scintillator powders

    Institute of Scientific and Technical Information of China (English)

    YUN; Ping; SHI; Ying

    2009-01-01

    The synthesis of cerium-doped lutetium oxyorthosilicate (LSO) polycrystalline powders was investigated by a hydrothermal proc-ess. The precursor was obtained by the hydrothermal reaction of Lu(NO3)3 with Na2SiO3 at 200 ℃ for 10 h by using urea as precipitator, fol-lowed by a calcination uader proper temperatures. The results of XRD indicated that the precursor was crystallized into A-type LSO phase at 1000 ℃, and transfetrred to B-type LSO phase when temperature was raised above 1050 ℃. After being heated at 1250 ℃ for 2 h, single phase of B-type LSO powder was synthesized with homogeneous distribution of particle size ranging from 200 to 300 nm. The photolumi-nescence spectrum of as-synthesized LSO: Ce powders showed a typical broad emission peak centered at 404 nm, corresponding to the 5d1-4f transition of Ce3+.

  12. Synthesis and characterization of super-microporous material with enhanced hydrothermal stability

    Indian Academy of Sciences (India)

    Shujie Wu; Ke Song; Jingqi Guan; Qiubin Kan

    2011-07-01

    Super-microporouos silicon material with high hydrothermal stability denoted as MCM-41-T has been prepared from mesoporous MCM-41 by high temperature treatment. The structural and chemical property of MCM-41-T has been characterized by X-ray diffraction, transmission electron microscopy, N2 adsorption-desorption, infrared spectroscopy and 29Si MAS NMR. The characteristic results show that Si–OH groups are forced to condense by high temperature treatment, and the pore size of MCM-41-T is around 1.5 nm in the super-microporous range. Compared with the original material MCM-41, the hydrothermal stability of MCM-41-T has been significantly enhanced.

  13. Hydrothermal synthesis, structural and physico-chemical characterizations of two Nasicon phosphates: M{sub 0.50}{sup II}Ti{sub 2}(PO{sub 4}){sub 3} (M = Mn, Co)

    Energy Technology Data Exchange (ETDEWEB)

    Essehli, Rachid, E-mail: essehli_rachid@yahoo.fr [Laboratory of Mineral Solid and Analytical Chemistry ' LMSAC' , Department of Chemistry, Faculty of Sciences, University Mohamed I, Po. Box 717, 60000 Oujda (Morocco); Bali, Brahim El [Laboratory of Mineral Solid and Analytical Chemistry ' LMSAC' , Department of Chemistry, Faculty of Sciences, University Mohamed I, Po. Box 717, 60000 Oujda (Morocco); Benmokhtar, S. [Laboratoire de Chimie des Materiaux Solides (LCMS) Universite HassanII-Mohammedia, Faculte des Sciences Ben M' Sik, Departement de Chimie, Casablanca (Morocco); Fejfarova, Karla; Dusek, Michal [Institute of Physics, Na Slovance 2, 182 21 Praha 8 (Czech Republic)

    2009-07-01

    The family of titanium Nasicon-phosphates of generic formula M{sub 0.5}{sup II}Ti{sub 2}(PO{sub 4}){sub 3} has been revisited using hydrothermal techniques. Two phases have been synthesized: Mn{sub 0.5}{sup II}Ti{sub 2}(PO{sub 4}){sub 3} (MnTiP) and Co{sub 0.5}{sup II}Ti{sub 2}(PO{sub 4}){sub 3} (CoTiP). Single crystal diffraction studies show that they exhibit two different structural types. Mn{sub 0.5}{sup II}Ti{sub 2}(PO{sub 4}){sub 3} phosphate crystallizes in the R-3 space group, with the cell parameters a = 8.51300(10) A and c = 21.0083(3) A (V = 1318.52(3) A{sup 3} and Z = 6). The Co{sub 0.5}{sup II}Ti{sub 2}(PO{sub 4}){sub 3} phosphate crystallizes in the R-3c space group, with a = 8.4608(9) A and c = 21.174(2) A (V = 1312.7(2) A{sup 3} and Z = 6). These two compounds are clearly related to the parent Nasicon-type rhombohedral structure, which can be described using [Ti{sub 2}(PO{sub 4}){sub 3}] framework composed of two [TiO{sub 6}] octahedral interlinked via three [PO{sub 4}] tetrahedra. {sup 31}P magic-angle spinning nuclear magnetic resonance (MAS-NMR) data are presented as supporting data. Curie-Weiss-type behavior is observed in the magnetic susceptibility. The phases are also characterized by IR spectroscopy and UV-visible.

  14. Synthesis of mesoporous cerium-zirconium mixed oxides by hydrothermal templating method

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Mesoporous cerium-zirconium mixed oxides were prepared by hydrothermal method using cetyl trimethyl ammonium bromide (CTAB) as template.The effects of amount of template,pH value of solution and hydrothermal temperature on mesostructure of samples were systematically investigated.The final products were characterized by XRD,TEM,FT-IR,and BET.The results indicate that all the cerium-zirconium mixed oxides present a meso-structure.At molar ratio of n(CTAB)/n((Ce)+(Zr))=0.15,pH value of 9,and hydrothermal temperature of 120 ℃,the samples obtained possess a specific surface area of 207.9 m2/g with pore diameter of 3.70 nm and pore volume of 0.19 cm3/g.

  15. MZnFe{sub 2}O{sub 4} (M = Ni, Mn) cubic superparamagnetic nanoparticles obtained by hydrothermal synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Freire, R. M. [Universidade Federal do Ceara-UFC, Grupo de Quimica de Materiais Avancados (GQMAT)- Departamento de Quimica Analitica e Fisico-Quimica (Brazil); Ribeiro, T. S.; Vasconcelos, I. F. [Universidade Federal do Ceara, Departamento de Engenharia Metalurgica e de Materiais (Brazil); Denardin, J. C. [Universidad de Santiago de Chile, USACH, Departamento de Fisica (Chile); Barros, E. B. [Universidade Federal do Ceara-UFC, Departamento de Fisica (Brazil); Mele, Giuseppe [Universita del Salento, Dipartimento di Ingegneria dell' Innovazione (Italy); Carbone, L. [IPCF-CNR, UOS Pisa (Italy); Mazzetto, S. E.; Fechine, P. B. A., E-mail: fechine@ufc.br [Universidade Federal do Ceara-UFC, Grupo de Quimica de Materiais Avancados (GQMAT)- Departamento de Quimica Analitica e Fisico-Quimica (Brazil)

    2013-05-15

    MZnFe{sub 2}O{sub 4} (M = Ni or Mn) cubic nanoparticles have been prepared by hydrothermal synthesis in mild conditions and short time without any procedure of calcinations. The structural and magnetic properties of the mixed ferrites were investigated by X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, Moessbauer spectroscopy, vibrating sample magnetometer, and Transmission electron microscopy (TEM). X-ray analysis showed peaks characteristics of the spinel phase. The average diameter of the nanoparticles observed by TEM measurements was approximately between 4 and 10 nm. Spectroscopy study of the spinel structure was performed based on Group Theory. The predicted bands were observed in FTIR and Raman spectrum. The magnetic parameters and Moessbauer spectroscopy were measured at room temperature and superparamagnetic behavior was observed for mixed ferrites. This kind of nanoparticles can be used as precursor in drug delivery systems, magnetic hyperthermia, ferrofluids, or magnetic imaging contrast agents.

  16. Surfactant-Assisted Hydrothermal Synthesis of Single Phase Pyrite FeS2 Nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Wadia, Cyrus; Wu, Yue; Gul, Sheraz; Volkman, Steven; Guo, Jinghua; Alivisatos, Paul

    2009-03-27

    Iron pyrite nanocrystals with high purity have been synthesized through a surfactant-assisted hydrothermal reaction under optimum pH value. These pyrite nanocrystals represent a new group of well-defined nanoscale structures for high-performance photovoltaic solar cells based on non-toxic and earth abundant materials.

  17. Synthesis and Characterization of La(OH)3 Nanorods by Hydrothermal Microemulsion Method

    Institute of Scientific and Technical Information of China (English)

    Yi Dong YIN; Guang Yan HONG

    2005-01-01

    La(OH)3 nanorods with diameters of 20-40 nm and lengths of 200-300 nm were synthesized by a hydrothermal microemulsion method. The structure and morphology of the final products were characterized by X-ray powder diffraction (XRD), transmission electron microscopy(TEM), and field emission scanning electron microscope (FESEM).

  18. Influence of the pH on the synthesis of reduced graphene oxide under hydrothermal conditions.

    Science.gov (United States)

    Bosch-Navarro, Concha; Coronado, Eugenio; Martí-Gastaldo, Carlos; Sánchez-Royo, J F; Gómez, Maribel Gómez

    2012-07-01

    Here we describe the important role played by the pH on the morphology and structure of the reduced graphite oxide (rGO) samples obtained by hydrothermal treatment of the previously prepared GO. The nature of the resulting samples has been studied on the basis of a complete battery of experimental techniques.

  19. FORMATION MECHANISM OF NANOSIZED TIN OXIDE (SnO2 POWDER DURING HYDROTHERMAL SYNTHESIS

    Directory of Open Access Journals (Sweden)

    M. Ozan ÖZER

    2011-06-01

    Full Text Available Preparation of nanosized SnO₂ electroceramic powders via hydrothermal synthesis was investigated as a function of initial concentration and treatment time in order to understand the formation and growth mechanisms. SnO₂ powder was successfully synthesized from the hydrous tin oxide by hydro- thermal synthesis at 200°C. Crystalline SnO₂ particles with a specific surface area as high as 170 m₂/g were produced in a single step without requiring any calcination process. As initial concentration of metal cation increases from 0.0125 to 0.05 M, an Ostwald ripening type growth process was observed in the crystallite size from 3.1 to 4.6 nm. Evolution of tin oxide particles was also investigated by al- tering the treatment time from 1 to 24 h and a diffusion controlled growth behavior was observed as a function of synthesis time.

  20. A novel synthesis of FeNbO{sub 4} nanorod by hydrothermal process

    Energy Technology Data Exchange (ETDEWEB)

    Dhak, Prasanta, E-mail: pdhak_chem@yahoo.com [Indian Institute of Technology, Department of Chemistry (India); Dhak, D. [Serampore College, Department of Chemistry (India); Das, M. [National Institute of Pharmaceutical Education and Research (NIPER), Center of Pharmaceutical Nanotechnology, Department of Pharmaceutics (India); Subashchandrabose, T.; Pramanik, P., E-mail: panchanan_123@yahoo.com [Indian Institute of Technology, Department of Chemistry (India)

    2011-09-15

    This study reports a facile, gram-scale synthesis of FeNbO{sub 4} nanorods via hydrothermal route, using iron nitrate [Fe(NO{sub 3}){sub 3}] and niobium tartarate (Nb tartarate) in presence of potassium peroxosulfate. The formation of single phase, polycrystalline orthorhombic structure of FeNbO{sub 4} was confirmed by the careful analysis of the X-ray diffraction (XRD) pattern. The average crystallite size, calculated using a few XRD peaks, was found to be 12.8 nm. As indicated by transmission electron microscopy (TEM) and field emission scanning electron microscopy, the average length and diameter of the rods were found to be only 25 Multiplication-Sign 7 nm and 47 Multiplication-Sign 14 nm, respectively. The selected area electron diffraction and high-resolution transmission electron microscopy (HRTEM) data of the single rod implied that FeNbO{sub 4} nanorods were polycrystalline in nature and grew up along the c-axis. HRTEM also revealed that the fringes are equidistant with a lattice separation of 0.91 Angstrom-Sign , which corresponded to the (111) plane of the FeNbO{sub 4} crystal. Elemental composition of the nanorods was confirmed using electron dispersive X-ray spectroscopy analysis while binding state of the surface was intervened through X-ray photoelectron spectroscopy. Mechanistic investigations suggested that potassium peroxosulfate played a crucial role in the unidirectional growth of particles. The synthetic method is simple, amenable to scale up and contributes a new tool box for the development of FeNbO{sub 4}-based one-dimensional (1D) structures that appears to be more promising for a myriad of applications, compared to their 3D counterparts.

  1. Hydrothermal Synthesis, Crystal Structure and Fluorescence Properties of a Three-dimensional Triply-bridged Binuclear Zinc(Ⅱ) Complex [Zn2(Mba)3(Phen)2EtOH)]·ClO4%Hydrothermal Synthesis, Crystal Structure and Fluorescence Properties of a Three-dimensional Triply-bridged Binuclear Zinc(Ⅱ) Complex [Zn2(Mba)3(Phen)2EtOH)]·ClO4

    Institute of Scientific and Technical Information of China (English)

    CHEN Zhi-Min; FENG Yong-Lan; YANG Ying-Qun; LI Wei; Zheng-Ji; CHEN Man-Sheng

    2012-01-01

    The novel complex [Zn2(Mba)3(Phen)2EtOH)]·ClO4 (Hrnba = methoxybenzoic acid, Phen = 1,10-phenanthroline, EtOH = ethanol) was synthesized by hydrothermal reactions, and its structure was determined by X-ray diffraction. The crystal belongs to the triclinic system, space group Pi with a = 1.15362(1), b = 1.3655(3), c = 1.61451(1) nm, α= 72.842(2), β = 83.259(3), y = 72.083(2)°, V = 2.3112(6) nm3, Z = 2,μ(MoKa) = 11.71 cm-1, F(000) = 1120, R = 0.0552 and wR = 0.1157 (I 〉 2σ(I)). The two centric zinc(H) ions in the complex locate in a distorted octahedral coordination geometry and a distorted trigonal bipyramid coordination geometry, respectively. Two bridging bidentate carboxyl groups and a μ2-O carboxyl group from three methoxybenzoic acids act as the bridge to link two Zn(Ⅱ) ions. The asymmetric units are connected by π-π packing interactions between aromatic rings to form a three-dimensional supramolecular network. The experimental results show a good fluorescence property for the complex.

  2. Synthesis of CdSe/ZnSe/ZnS Core/Shell Structure Quantum Dots by Hydrothermal Method%水热法合成CdSe/ZnSe/ZnS核壳结构量子点

    Institute of Scientific and Technical Information of China (English)

    胥燕; 王新; 翟镇德; 刘敏; 苏秀荣

    2014-01-01

    In the study, 3-mercaptopropionic acid modified CdSe/ZnSe/ZnS core/shell structure quantum dots (QDs) with high fluorescence were prepared by hydrothermal method and characterized via transmission electron microscopy (TEM). The influence factors of the fluorescence intensity and the stability of QDs have been studied. Results showed that excellent CdSe/ZnSe/ZnS QDs with uniform diameter (5-8 nm) were obtained. The prepared CdSe/ZnSe/ZnS QDs emit blue-violet light (446 nm) when excited at 372 nm with low toxicity, high fluorescence intensity and excellent stability, endowing the synthesized CdSe/ZnSe/ZnS QDs applied in biochemical analysis.%本研究采用水热法合成了3-巯基丙酸稳定的具有高荧光活性的CdSe/ZnSe/ZnS核/壳结构量子点,并通过透射电镜对量子点的形貌进行了表征。研究了影响量子点荧光强度的因素,并分析了量子点的稳定性。结果表明,水热法合成的CdSe/ZnSe/ZnS量子点,分布均匀,粒径大小均匀,约为5~8 nm。当激发波长为372 nm时CdSe/ZnSe/ZnS量子点可发射蓝紫色(446 nm)荧光,荧光活性高、荧光稳定性好,毒性低,可用于生物荧光标记、组分测定等。

  3. A facile hydrothermal synthesis, characterization and magnetic properties of mesoporous CoFe{sub 2}O{sub 4} nanospheres

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, M. Penchal, E-mail: reddy@nimte.ac.cn [Center for Advanced Materials, Qatar University, Doha 2713 (Qatar); Mohamed, A.M.A. [Center for Advanced Materials, Qatar University, Doha 2713 (Qatar); Department of Metallurgical and Materials Engineering, Faculty of Petroleum and Mining Engineering, Suez University, Suez 4372 (Egypt); Zhou, X.B.; Du, S.; Huang, Q. [Ningbo Institute of Materials Technology and Engineering (NIMTE), Chinese Academy of Sciences (CAS), Ningbo 315201, Zhejiang, RP China (China)

    2015-08-15

    Mesoporous CoFe{sub 2}O{sub 4} nanospheres with an average size of 180 nm were fabricated via a facile hydrothermal process using ethylene glycol as solvent and sodium acetate (NaAc) as electrostatic stabilizer. In this method, ethylene glycol plays a vital role in the formation of cobalt nanoospheres as a solvent and reducing agent. The structure and morphology of the prepared materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The nanospheres exhibited ferromagnetic properties with high saturation magnetization value of about 60.19 emu/g at room temperature. The BET surface area of the nanospheres was determined using the nitrogen absorption method. The porous CoFe{sub 2}O{sub 4} nanospheres displayed good magnetic properties, which may provide a very promising candidate for their applications in target drug delivery. - Highlights: • CoFe{sub 2}O{sub 4} nanospheres were prepared by hydrothermal synthesis for the first time. • Average grain size was found to be 180 nm. • Its structural, morphological, magnetic behavior was studied. • TEM observations confirmed the spherical morphology of the mesoporous ferrites.

  4. Hydrothermal synthesis of nanostructured manganese oxide as cathodic catalyst in a microbial fuel cell fed with leachate.

    Science.gov (United States)

    Haoran, Yuan; Lifang, Deng; Tao, Lu; Yong, Chen

    2014-01-01

    Much effort has been devoted to the synthesis of novel nanostructured MnO2 materials because of their unique properties and potential applications as cathode catalyst in Microbial fuel cell. Hybrid MnO2 nanostructures were fabricated by a simple hydrothermal method in this study. Their crystal structures, morphology, and electrochemical characters were carried out by FESEM, N2-adsorption-desorption, and CV, indicating that the hydrothermally synthesized MnO2 (HSM) was structured by nanorods of high aspect ratio and multivalve nanoflowers and more positive than the naturally synthesized MnO2 (NSM), accompanied by a noticeable increase in oxygen reduction peak current. When the HSM was employed as the cathode catalyst in air-cathode MFC which fed with leachate, a maximum power density of 119.07 mW/m(2) was delivered, 64.68% higher than that with the NSM as cathode catalyst. Furthermore, the HSM via a 4-e pathway, but the NSM via a 2-e pathway in alkaline solution, and as 4-e pathway is a more efficient oxygen reduction reaction, the HSM was more positive than NSM. Our study provides useful information on facile preparation of cost-effective cathodic catalyst in air-cathode MFC for wastewater treatment.

  5. Hydrothermal Synthesis of Nanostructured Manganese Oxide as Cathodic Catalyst in a Microbial Fuel Cell Fed with Leachate

    Directory of Open Access Journals (Sweden)

    Yuan Haoran

    2014-01-01

    Full Text Available Much effort has been devoted to the synthesis of novel nanostructured MnO2 materials because of their unique properties and potential applications as cathode catalyst in Microbial fuel cell. Hybrid MnO2 nanostructures were fabricated by a simple hydrothermal method in this study. Their crystal structures, morphology, and electrochemical characters were carried out by FESEM, N2-adsorption-desorption, and CV, indicating that the hydrothermally synthesized MnO2 (HSM was structured by nanorods of high aspect ratio and multivalve nanoflowers and more positive than the naturally synthesized MnO2 (NSM, accompanied by a noticeable increase in oxygen reduction peak current. When the HSM was employed as the cathode catalyst in air-cathode MFC which fed with leachate, a maximum power density of 119.07 mW/m2 was delivered, 64.68% higher than that with the NSM as cathode catalyst. Furthermore, the HSM via a 4-e pathway, but the NSM via a 2-e pathway in alkaline solution, and as 4-e pathway is a more efficient oxygen reduction reaction, the HSM was more positive than NSM. Our study provides useful information on facile preparation of cost-effective cathodic catalyst in air-cathode MFC for wastewater treatment.

  6. Simulation, design and proof-of-concept of a two-stage continuous hydrothermal flow synthesis reactor for synthesis of functionalized nano-sized inorganic composite materials

    DEFF Research Database (Denmark)

    Zielke, Philipp; Xu, Yu; Simonsen, Søren Bredmose

    2016-01-01

    Computational fluid dynamics simulations were employed to evaluate several mixer geometries for a novel two-stage continuous hydrothermal flow synthesis reactor. The addition of a second stage holds the promise of allowing the synthesis of functionalized nano-materials as for example core...

  7. Hydrothermal synthesis, structure, and optical properties of two nanosized Ln26 @CO3 (Ln=Dy and Tb) cluster-based lanthanide-transition-metal-organic frameworks (Ln MOFs).

    Science.gov (United States)

    Zhang, Yu; Huang, Lian; Miao, Hao; Wan, Hong Xiang; Mei, Hua; Liu, Ying; Xu, Yan

    2015-02-16

    Two Ln26 @CO3 (Ln=Dy and Tb) cluster-based lanthanide-transition-metal-organic frameworks (Ln MOFs) formulated as [Dy26 Cu3 (Nic)24 (CH3 COO)8 (CO3 )11 (OH)26 (H2 O)14 ]Cl ⋅3 H2 O (1; HNic=nicotinic acid) and [Tb26 NaAg3 (Nic)27 (CH3 COO)6 (CO3 )11 (OH)26 Cl(H2 O)15 ]⋅7.5 H2 O (2) have been successfully synthesized by hydrothermal methods and characterized by IR, thermogravimetric analysis (TGA), elemental analysis, and single X-ray diffraction. Compound 1 crystallizes in the monoclinic space group Cc with a=35.775(12) Å, b=33.346(11) Å, c=24.424(8) Å, β=93.993(5)°, V=29065(16) Å(3) , whereas 2 crystallizes in the triclinic space group P$\\bar 1$ with a=20.4929(19) Å, b=24.671(2) Å, c=29.727(3) Å, α=81.9990(10)°, β=88.0830(10)°, γ=89.9940(10)°, V=14875(2) Å(3) . Structural analysis indicates the framework of 1 is a 3D perovskite-like structure constructed out of CO3 @Dy26 building units and Cu(+) centers by means of nicotinic acid ligand bridging. In 2, however, nanosized CO3 @Tb26 units and [Ag3 Cl](2+) centers are connected by Nic(-) bridges to give rise to a 2D structure. It is worth mentioning that this kind of 4d-4f cluster-based MOF is quite rare as most of the reported analogous compounds are 3d-4f ones. Additionally, the solid-state emission spectra of pure compound 2 at room temperature suggest an efficient energy transfer from the ligand Nic(-) to Tb(3+) ions, which we called the "antenna effect". Compound 2 shows a good two-photon absorption (TPA) with a TPA coefficient of 0.06947 cm GM(-1) (1 GM=10(-50)  cm(4)  s photon(-1) ), which indicates that compound 2 might be a good choice for third-order nonlinear optical materials.

  8. Hydrothermal synthesis of NiWO4 crystals for high performance non-enzymatic glucose biosensors

    Science.gov (United States)

    Mani, Sivakumar; Vediyappan, Veeramani; Chen, Shen-Ming; Madhu, Rajesh; Pitchaimani, Veerakumar; Chang, Jia-Yaw; Liu, Shang-Bin

    2016-01-01

    A facile hydrothermal route for the synthesis of ordered NiWO4 nanocrystals, which show promising applications as high performance non-enzymatic glucose sensor is reported. The NiWO4-modified electrodes showed excellent sensitivity (269.6 μA mM−1 cm−2) and low detection limit (0.18 μM) for detection of glucose with desirable selectivity, stability, and tolerance to interference, rendering their prospective applications as cost-effective, enzyme-free glucose sensors. PMID:27087561

  9. Hydrothermal synthesis and characterisation of amine-templated ...

    African Journals Online (AJOL)

    Two coordination polymers [CH3CH2NH3]2M3(NH3C6H4CO2)2(HPO4)4 ... (I) and 3926 – 3760cm-1 (II) is due to the presence of water molecule in the structure. ... The complexes were thermally stable up to 3000C, after which the organic ...

  10. Confined-Pyrolysis as an Experimental Method for Hydrothermal Organic Synthesis

    Science.gov (United States)

    Leif, Roald N.; Simoneit, Bernd R. T.

    1995-01-01

    A closed pyrolysis system has been developed as a tool for studying the reactions of organic compounds under extreme hydrothermal conditions. Small high pressure stainless steel vessels in which the ratio of sediment or sample to water has been adjusted to eliminate the headspace at peak experimental conditions confines the organic components to the bulk solid matrix and eliminates the partitioning of the organic compounds away from the inorganic components during the experiment. Confined pyrolysis experiments were performed to simulate thermally driven catagenetic changes in sedimentary organic matter using a solids to water ratio of 3.4 to 1. The extent of alteration was measured by monitoring the steroid and triterpenoid biomarkers and polycyclic aromatic hydrocarbon distributions. These pyrolysis experiments duplicated the hydrothermal transformations observed in nature. Molecular probe experiments using alkadienes, alkenes and alkanes in H2O and D2O elucidated the isomerization and hydrogenation reactions of aliphatic and the competing oxidative reactions occurring under hydrothermal conditions. This confined pyrolysis technique is being applied to test experiments on organic synthesis of relevance to chemical evolution for the origin of life.

  11. Confined-pyrolysis as an experimental method for hydrothermal organic synthesis

    Science.gov (United States)

    Leif, Roald N.; Simoneit, Bernd R. T.

    1995-10-01

    A closed pyrolysis system has been developed as a tool for studying the reactions of organic compounds under extreme hydrothermal conditions. Small high pressure stainless steel vessels in which the ratio of sediment or sample to water has been adjusted to eliminate the headspace at peak experimental conditions confines the organic components to the bulk solid matrix and eliminates the partitioning of the organic compounds away from the inorganic components during the experiment. Confined pyrolysis experiments were performed to simulate thermally driven catagenetic changes in sedimentary organic matter using a solids to water ratio of 3.4 to 1. The extent of alteration was measured by monitoring the steroid and triterpenoid biomarkers and polycyclic aromatic hydrocarbon distributions. These pyrolysis experiments duplicated the hydrothermal transformations observed in nature. Molecular probe experiments using alkadienes, alkenes and alkanes in H2O and D2O elucidated the isomerization and hydrogenation reactions of aliphatic compounds and the competing oxidative reactions occurring under hydrothermal conditions. This confined pyrolysis technique is being applied to test experiments on organic synthesis of relevance to chemical evolution for the origin of life.

  12. Confined-Pyrolysis as an Experimental Method for Hydrothermal Organic Synthesis

    Science.gov (United States)

    Leif, Roald N.; Simoneit, Bernd R. T.

    1995-01-01

    A closed pyrolysis system has been developed as a tool for studying the reactions of organic compounds under extreme hydrothermal conditions. Small high pressure stainless steel vessels in which the ratio of sediment or sample to water has been adjusted to eliminate the headspace at peak experimental conditions confines the organic components to the bulk solid matrix and eliminates the partitioning of the organic compounds away from the inorganic components during the experiment. Confined pyrolysis experiments were performed to simulate thermally driven catagenetic changes in sedimentary organic matter using a solids to water ratio of 3.4 to 1. The extent of alteration was measured by monitoring the steroid and triterpenoid biomarkers and polycyclic aromatic hydrocarbon distributions. These pyrolysis experiments duplicated the hydrothermal transformations observed in nature. Molecular probe experiments using alkadienes, alkenes and alkanes in H2O and D2O elucidated the isomerization and hydrogenation reactions of aliphatic and the competing oxidative reactions occurring under hydrothermal conditions. This confined pyrolysis technique is being applied to test experiments on organic synthesis of relevance to chemical evolution for the origin of life.

  13. APPLICATION OF HYDROTHERMAL TECHNOLOGY IN MATERIAL SYNTHESIS - A SELECTIVE REVIEW

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    1 IntroductionWater in super- and sub- critical conditi.ons hasbeen revealed to be a unique medium for chemicalprocesses. The characteristic properties in super- andsub- critical water originate from the variation ofmicroscopic. structure (hydrogen bonding, clusterformation, etc.) and basic physic-chemical propertiessuch as Kw, viscosity and permittivity of water at hightemperature and high-pressure ill. The hydrothermalregion is defined as temperature' below and pressureabove the boiling point of pure wate...

  14. Synthesis of indium oxide cubic crystals by modified hydrothermal route for application in room temperature flexible ethanol sensors

    Energy Technology Data Exchange (ETDEWEB)

    Seetha, M., E-mail: seetha.phy@gmail.com [Department of Physics, SRM University, Kattankulathur, Kancheepuram Dt 603 203 (India); Meena, P. [Department of Physics, PSGR Krishnammal College for Women, Coimbatore 641 046 (India); Mangalaraj, D., E-mail: dmraj800@yahoo.com [DRDO-BU Centre for Life Sciences, Bharathiar University Campus, Coimbatore (India); Department of Nanoscience and Technology, Bharathiar University, Coimbatore 641 014 (India); Masuda, Yoshitake [National Institute of Advanced Industrial Science and Technology (AIST), Nagoya 463-8560 (Japan); Senthil, K. [School of Advanced Materials Science and Engineering, Sungkyunkwan University (Suwon Campus), Cheoncheon-dong 300, Jangan-gu, Suwon 440-746 (Korea, Republic of)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer For the first time HMT is used in the preparation of indium oxide. Black-Right-Pointing-Pointer HMT itself acts as base for the precursor and results in cubic indium hydroxide. Black-Right-Pointing-Pointer Modified hydrothermal route used for the preparation of cubic indium oxide crystals. Black-Right-Pointing-Pointer As a new approach a composite film synthesized with prepared indium oxide. Black-Right-Pointing-Pointer Film showed good response to ethanol vapours with quick response and recovery times. - Abstract: Indium oxide cubic crystals were prepared by using hexamethylenetetramine and indium chloride without the addition of any structure directing agents. The chemical route followed in the present work was a modified hydrothermal synthesis. The average crystallite size of the prepared cubes was found to be 40 nm. A blue emission at 418 nm was observed at room temperature when the sample was excited with a 380 nm Xenon lamp. This emission due to oxygen vacancies made the material suitable for gas sensing applications. The synthesized material was made as a composite film with polyvinyl alcohol which was more flexible than the films prepared on glass substrates. This flexible film was used as a sensing element and tested with ethanol vapours at room temperature. The film showed fast response as well as recovery to ethanol vapours with a sensor response of about 1.4 for 100 ppm of the gas.

  15. Synthesis of dittmarite/Mg(OH){sub 2} composite coating on AZ31 using hydrothermal treatment

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Qing, E-mail: qzhaoyuping@bit.edu.cn; Mahmood, Waqas; Zhu, Yanying

    2016-03-30

    Highlights: • Synthesis of dittmarite Mg(OH){sub 2} coating on AZ31 alloy by hydrothermal method. • The mechanism of composite coating growth and its characterizations. • The coating is corrosion resistant significantly. • Lack of hydroxyl deposition on the coating surface. • Strong adhesion between the coating and the substrate. • The synthesized coating meets the cytotoxicity standards. - Abstract: In this work, we have used hydrothermal method for the synthesis of dittmarite/Mg(OH){sub 2} composite (DMC) layer on AZ31 alloy of magnesium. The synthesized coating was characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectroscopy (EDS). In a test immersion into the Hank's mixture for 31 days, the synthesized coating inhibited corrosion of AZ31 significantly and the amorphous calcium apatite precursor deposited on the coating surface. In another tape test, we noticed strong adhesion between the coating and substrate that eventually concludes that the synthesized coating is hydrophilic and a promising candidate to be used in the absorbable implant materials. Besides, the cytotoxicity of the AZ31 alloy with DMC coating, grown under different conditions on L-929 cells in vitro was examined indirectly through the growth inhibition method (MTT assay). The cytotoxicity of the deposited coating lie between 0 ∼ 1 that indicates it as a promising biomaterial.

  16. Carbon Isotope Systematics in Mineral-Catalyzed Hydrothermal Organic Synthesis Processes at High Temperature and Pressures

    Science.gov (United States)

    Fu, Qi; Socki, R. A.; Niles, Paul B.

    2011-01-01

    Observation of methane in the Martian atmosphere has been reported by different detection techniques. Reduction of CO2 and/or CO during serpentization by mineral surface catalyzed Fischer-Tropsch Type (FTT) synthesis may be one possible process responsible for methane generation on Mars. With the evidence a recent study has discovered for serpentinization in deeply buried carbon rich sediments, and more showing extensive water-rock interaction in Martian history, it seems likely that abiotic methane generation via serpentinization reactions may have been common on Mars. Experiments involving mineral-catalyzed hydrothermal organic synthesis processes were conducted at 750 C and 5.5 Kbars. Alkanes, alcohols and carboxylic acids were identified as organic compounds. No "isotopic reversal" of delta C-13 values was observed for alkanes or carboxylic acids, suggesting a different reaction pathway than polymerization. Alcohols were proposed as intermediaries formed on mineral surfaces at experimental conditions. Carbon isotope data were used in this study to unravel the reaction pathways of abiotic formation of organic compounds in hydrothermal systems at high temperatures and pressures. They are instrumental in constraining the origin and evolution history of organic compounds on Mars and other planets.

  17. Structure and properties of loaded silica contacts during pressure solution: impedance spectroscopy measurements under hydrothermal conditions

    NARCIS (Netherlands)

    Noort, R. van; Spiers, C.J.; Peach, C.J.

    2011-01-01

    In order to investigate directly the structure and properties of grain boundaries in silicatematerials undergoing pressure solution, in situmeasurements of these properties are required. We report electrical impedance spectroscopy measurements, performed, under hydrothermal conditions,

  18. Synthesis and Characterization of Porous Magnesium Aluminate Spinel by Hydrothermal Process

    Institute of Scientific and Technical Information of China (English)

    WANG; Xiuhui; DUAN; Jinxia; LU; Shengbo; YIN; Jianlong; SU; Zhenguo; GAO; Hong; YANG; Jinlong

    2015-01-01

    Magnesium aluminate spinel has a great prospect in catalyst supports due to the porous structure, good catalytic activity, high thermal stability and the presence of two active centers as acid and alkaline. The magnesium aluminate spinel powders were synthesized by a hydrothermal process. The samples were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and N2 adsorption-desorption isotherms, respectively. The particle surface with the laminated structure increases with the increase of hydrothermal temperature and hydrothermal time. The spinel has a worm-like porous structure, and the pores become smaller and well-distributed under hexadecyl trimethyl ammonium bromide condition. The phase of the spinel appears at 450°C and the perfect crystalline structure emerges at 600°C. The percentage of Mg Al2O4 spinel increases with the increase of heat treatment temperature. The spinel has a great specific surface area(i.e., 245.68–58.65 m2/g) when the calcinating temperature increases from 500 to 1200°C. Moreover, the specific surface area is 195.11 m2/g 1 at.% hexadecyl trimethyl ammonium bromide.

  19. Hydrothermal synthesis, structure, and optical properties of two nanosized Ln{sub 26} rate at CO{sub 3} (Ln=Dy and Tb) cluster-based lanthanide-transition-metal-organic frameworks (Ln MOFs)

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yu; Huang, Lian; Miao, Hao; Wan, Hong Xiang; Mei, Hua; Liu, Ying [State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University (China); Xu, Yan [State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University (China); State Key Laboratory of Coordination Chemistry, Nanjing Tech University (China)

    2015-02-16

    Two Ln{sub 26} rate at CO{sub 3} (Ln=Dy and Tb) cluster-based lanthanide-transition-metal-organic frameworks (Ln MOFs) formulated as [Dy{sub 26}Cu{sub 3}(Nic){sub 24}(CH{sub 3}COO){sub 8}(CO{sub 3}){sub 11}(OH){sub 26}(H{sub 2}O){sub 14}]Cl . 3 H{sub 2}O (1; HNic=nicotinic acid) and [Tb{sub 26}NaAg{sub 3}(Nic){sub 27}(CH{sub 3}COO){sub 6}(CO{sub 3}){sub 11}(OH){sub 26}Cl(H{sub 2}O){sub 15}] . 7.5 H{sub 2}O (2) have been successfully synthesized by hydrothermal methods and characterized by IR, thermogravimetric analysis (TGA), elemental analysis, and single X-ray diffraction. Compound 1 crystallizes in the monoclinic space group Cc with a=35.775(12) Aa, b=33.346(11) Aa, c=24.424(8) Aa, β=93.993(5) , V=29065(16) Aa{sup 3}, whereas 2 crystallizes in the triclinic space group P anti 1 with a=20.4929(19) Aa, b=24.671(2) Aa, c=29.727(3) Aa, α=81.9990(10) , β=88.0830(10) , γ=89.9940(10) , V=14875(2) Aa{sup 3}. Structural analysis indicates the framework of 1 is a 3D perovskite-like structure constructed out of CO{sub 3} rate at Dy{sub 26} building units and Cu{sup +} centers by means of nicotinic acid ligand bridging. In 2, however, nanosized CO{sub 3} rate at Tb{sub 26} units and [Ag{sub 3}Cl]{sup 2+} centers are connected by Nic{sup -} bridges to give rise to a 2D structure. It is worth mentioning that this kind of 4d-4f cluster-based MOF is quite rare as most of the reported analogous compounds are 3d-4f ones. Additionally, the solid-state emission spectra of pure compound 2 at room temperature suggest an efficient energy transfer from the ligand Nic{sup -} to Tb{sup 3+} ions, which we called the ''antenna effect''. Compound 2 shows a good two-photon absorption (TPA) with a TPA coefficient of 0.06947 cm GM{sup -1} (1 GM = 10{sup -50} cm{sup 4} s photon{sup -1}), which indicates that compound 2 might be a good choice for third-order nonlinear optical materials. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Hydrothermal Synthesis of Lanthanide Stannates Pyrochlore Nanocrystals for Catalytic Combustion of Soot Particulates

    Directory of Open Access Journals (Sweden)

    Xiaomin Zhang

    2015-01-01

    Full Text Available Nanocrystalline La2Sn2O7 and La2Sn1.8Co0.2O7 with a phase-pure pyrochlore structure were synthesized by a hydrothermal method, and their catalytic activity was investigated for soot combustion. The as-synthesized catalysts presented relatively larger surface area, and pore volume, which was benefit to the gas molecule diffusion in the reaction. A uniform spherical structure with particle size of 200–500 nm was found in SEM. The samples via hydrothermal route are more active for catalytic soot combustion, ascribing to the spherical morphology, high surface area and improved oxygen mobility. After Co, the reducibility was improved and surface oxygen vacancy was produced, resulting in the enhanced activity and selectivity to CO2 formation.

  1. Hydrothermal Synthesis of Lanthanide Stannates Pyrochlore Nanocrystals for Catalytic Combustion of Soot Particulates.

    Science.gov (United States)

    Zhang, Xiaomin; Liu, Xuhui; Lu, Peng; Wang, Liguo; Zhang, Zhaoliang; Wang, Xiuju; Wang, Zhongpeng

    2015-01-01

    Nanocrystalline La2Sn2O7 and La2Sn1.8Co0.2O7 with a phase-pure pyrochlore structure were synthesized by a hydrothermal method, and their catalytic activity was investigated for soot combustion. The as-synthesized catalysts presented relatively larger surface area, and pore volume, which was benefit to the gas molecule diffusion in the reaction. A uniform spherical structure with particle size of 200-500 nm was found in SEM. The samples via hydrothermal route are more active for catalytic soot combustion, ascribing to the spherical morphology, high surface area and improved oxygen mobility. After Co, the reducibility was improved and surface oxygen vacancy was produced, resulting in the enhanced activity and selectivity to CO2 formation.

  2. Magnetic properties of hematite (α-Fe{sub 2}O{sub 3}) nanoparticles prepared by hydrothermal synthesis method

    Energy Technology Data Exchange (ETDEWEB)

    Tadic, Marin, E-mail: marint@vinca.rs [Condensed Matter Physics Laboratory, Vinca Institute, University of Belgrade, POB 522, 11001 Belgrade (Serbia); Panjan, Matjaz [Jožef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia); Damnjanovic, Vesna [Department of Physics, University of Belgrade, Faculty of Mining and Geology, Belgrade (Serbia); Milosevic, Irena [Centre de Recherche sur la Matière Divisée, UMR 6619, CNRS-Université d’Orléans, 1b rue de la Férollerie, 45071 Orléans Cedex 2 (France); Laboratoire CSPBAT, UMR 7244 CNRS Université Paris 13, 93017 Bobigny Cedex (France)

    2014-11-30

    Graphical abstract: - Highlights: • Hematite nanoparticles are synthesized by using the hydrothermal synthesis method. • The SQUID measurements show blocking temperature T{sub B} = 52 K and superparamagnetism. • A TEM measurements show spherical particles and narrow size distribution. • The sample did not exhibit the Morin transition. • The magnetic moment μ{sub p} = 657 μ{sub B} and diameter d = 8 nm were determined. - Abstract: Hematite (α-Fe{sub 2}O{sub 3}) nanoparticles are successfully synthesized by using the hydrothermal synthesis method. An X-ray powder diffraction (XRPD) of the sample shows formation of the nanocrystalline α-Fe{sub 2}O{sub 3} phase. A transmission electron microscopy (TEM) measurements show spherical morphology of the hematite nanoparticles and narrow size distribution. An average hematite nanoparticle size is estimated to be about 8 nm by TEM and XRD. Magnetic properties were measured using a superconducting quantum interference device (SQUID) magnetometry. Investigation of the magnetic properties of hematite nanoparticles showed a divergence between field-cooled (FC) and zero-field-cooled (ZFC) magnetization curves below T{sub irr} = 103 K (irreversibility temperature). The ZFC magnetization curve showed maximum at T{sub B} = 52 K (blocking temperature). The sample did not exhibit the Morin transition. The M(H) (magnetization versus magnetic field) dependence at 300 K showed properties of superparamagnetic iron oxide nanoparticles (SPION). The M(H) data were successfully fitted by the Langevin function and magnetic moment μ{sub p} = 657 μ{sub B} and diameter d = 8.1 nm were determined. Furthermore, magnetic measurements showed high magnetization at room temperature (M{sub S} = 3.98 emu/g), which is desirable for application in spintronics and biomedicine. Core–shell structure of the nanoparticles was used to describe high magnetization of the hematite nanoparticles.

  3. Synthesis and Characterization of Porous Magnesium Aluminate Spinel by Hydrothermal Process

    Institute of Scientific and Technical Information of China (English)

    WANG Xiuhui; DUAN Jinxia; LU Shengbo; YIN Jianlong; SU Zhenguo; GAO Hong; YANG Jinlong

    2015-01-01

    Magnesium aluminate spinel has a great prospect in catalyst supports due to the porousstructure, good cata-lytic activity, high thermal stability and the presence of two active centers as acid and alkaline. The magnesium alumi-nate spinel powders were synthesized by a hydrothermal process. The samples were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and N2adsorption-desorption isotherms, respectively. The particle surface with the laminated structure increases with the increase of hydrothermal temperature and hydro-thermal time. The spinel has a worm-like porous structure, and the pores become smaller and well-distributed under hexadecyl trimethyl ammonium bromide condition. The phase of the spinel appears at 450°C and the perfect crystalline structure emerges at 600°C. The percentage of MgAl2O4spinel increases with the increase of heat treatment temperature. The spinel has a great specific surface area (i.e., 245.68–58.65 m2/g) when the calcinating temperature increases from 500 to 1200°C. Moreover, the specific surface area is 195.11 m2/g 1 at.% hexadecyl trimethyl ammonium bromide.

  4. Evaluating reaction pathways of hydrothermal abiotic organic synthesis at elevated temperatures and pressures using carbon isotopes

    Science.gov (United States)

    Fu, Qi; Socki, Richard A.; Niles, Paul B.

    2015-04-01

    Experiments were performed to better understand the role of environmental factors on reaction pathways and corresponding carbon isotope fractionations during abiotic hydrothermal synthesis of organic compounds using piston cylinder apparatus at 750 °C and 5.5 kbars. Chemical compositions of experimental products and corresponding carbon isotopic values were obtained by a Pyrolysis-GC-MS-IRMS system. Alkanes (methane and ethane), straight-chain saturated alcohols (ethanol and n-butanol) and monocarboxylic acids (formic and acetic acids) were generated with ethanol being the only organic compound with higher δ13C than CO2. CO was not detected in experimental products owing to the favorable water-gas shift reaction under high water pressure conditions. The pattern of δ13C values of CO2, carboxylic acids and alkanes are consistent with their equilibrium isotope relationships: CO2 > carboxylic acids > alkanes, but the magnitude of the fractionation among them is higher than predicted isotope equilibrium values. In particular, the isotopic fractionation between CO2 and CH4 remained constant at ∼31‰, indicating a kinetic effect during CO2 reduction processes. No "isotope reversal" of δ13C values for alkanes or carboxylic acids was observed, which indicates a different reaction pathway than what is typically observed during Fischer-Tropsch synthesis under gas phase conditions. Under constraints imposed in experiments, the anomalous 13C isotope enrichment in ethanol suggests that hydroxymethylene is the organic intermediate, and that the generation of other organic compounds enriched in 12C were facilitated by subsequent Rayleigh fractionation of hydroxymethylene reacting with H2 and/or H2O. Carbon isotope fractionation data obtained in this study are instrumental in assessing the controlling factors on abiotic formation of organic compounds in hydrothermal systems. Knowledge on how environmental conditions affect reaction pathways of abiotic synthesis of organic

  5. Hydrothermal synthesis, structural elucidation, spectroscopic studies, thermal behavior and luminescence properties of a new 3-d compound: FeAlF2(C10H8N2)(HPO4)2(H2O)

    Science.gov (United States)

    Bouzidia, Nabaa; Salah, Najet; Hamdi, Besma; Ben Salah, Abdelhamid

    2017-04-01

    The study of metal phosphate has been a proactive field of research thanks to its applied and scientific importance, especially in terms of the development of optical devices such as solid state lasers as well as optical fibers. The present paper seeks to investigate the synthesis, crystal structure, elemental analysis and properties of FeAlF2(C10H8N2)(HPO4)2(H2O) compound investigated by spectroscopic studies (FT-IR and FT-Raman), thermal behavior and luminescence. The Hirshfeld surface analysis and 2-D fingerprint plot have been performed to explore the behavior of these weak interactions and crystal cohesion. This investigation shows that the molecules are connected by hydrogen bonds of the type Osbnd H⋯O and Osbnd H⋯F. In addition, the 2,2'‒bipyridine ligand plays a significant role in the construction of 3-D supramolecular framework via π‒π stacking. FT‒IR and FT‒Raman spectra were used so as to ease the responsibilities of the vibration modes of the title compound. The thermal analysis (TGA) study shows a mass loss evolution as a temperature function. Finally, the optical properties were evaluated by photoluminescence spectroscopy.

  6. Negative Feedback Effect of Microwave Irradiation in the Microwave—assisted Hydrothermal Synthesis of Bi2S3 Nanorods

    Institute of Scientific and Technical Information of China (English)

    陶秀成; 邵名望

    2002-01-01

    The microwave-assisted hydrothermal synthesis of Bi2S3 nanorods was reported.The result showed that microwave irradiation can help to produce Bi2S3 nanorods in very short time.There is a negative feedback effcet which increases the degree of crystallinity in the reaction.

  7. Negative Feedback Effect of Microwave Irradiation in the Microwave-assisted Hydrothermal Synthesis of Bi2S3 Nanorods

    Institute of Scientific and Technical Information of China (English)

    TAO,Xiu-Cheng(陶秀成); SHAO,Ming-Wang(邵名望)

    2002-01-01

    The microwave-assisted hydrothermal synthesis of Bi2S3 nanorods was reported. The result showed that microwave irradiation can help to produce Bi2S3 nanorods in very short time.There is a negative feedback effect which increases the degree of crystallinity in the reaction.

  8. Hydrothermal synthesis of 2D ordered macroporous ZnO films

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The ZnO films with two-dimensional ordered macroporous structure were successfully fabricated through hydrothermal crystal growth of ZnO on the ZnO substrate covered with a mouolayer of polystyrene (PS) spheres as template.The precursor solution of hydrothermal crystal growth of ZnO were prepared by equitramine (HMT).The confinement effect of the PS spheres template on the growth of ZnO nanorods and the influence of sodium citrate on the crystal growth of ZnO had been studied.The film surface morphology and the preferential growth of ZnO crystal were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD),respectively.Also,the photoluminescence spectrum of ZnO films had been measured,and the corresponding mechanism was discussed.

  9. Facile synthesis of hydroxyapatite particles from cockle shells(Anadaragranosaby hydrothermal method

    Directory of Open Access Journals (Sweden)

    Yelmida Azis

    2015-06-01

    Full Text Available Hydroxyapatite particles, Ca10(PO46(OH2, (HAp, have been successfully synthesized by hydrothermal method using cockle shells (Anadaragranosawaste as the starting material. The cockle shells were calcined, hydrated (slaking and undergone carbonation to form precipitated calcium carbonate (PCC.The PCC was added with (NH42HPO4 to form HAp by varying the temperatures and reaction times under basic condition (pH 10 – 11. The X-ray Diffraction (XRDpatterns revealed that the excellent product of HAp with hexagonal crystal structure can obtained via facile hydrothermal procedure (140 oC for 16 h. Fourier transform infrared spectroscopy (FTIR spectra analyses showed the presence of OH, HPO42‒, and PO43‒ absorption bands, indicating the formation of HAp. The dried HAp particles powder was extremely pure with a specific surface area of 17.8 m²/g.

  10. Hydrothermal synthesis and magnetic properties of RMn 2O 5 ( R=La, Pr, Nd, Tb, Bi) and LaMn 2O 5+δ

    Science.gov (United States)

    Chen, Yan; Yuan, Hongming; Tian, Ge; Zhang, Ganghua; Feng, Shouhua

    2007-04-01

    RMn 2O 5 ( R=La, Pr, Nd, Tb, Bi) crystallites were prepared by a mild hydrothermal method and characterized by powder X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy (XPS) and magnetic measurement. The formation of manganates was sensitive to the alkalinities and Mn-containing precursors of the reaction mixtures. This family of manganates is isostructural and has a space group of Pbam. The magnetic measurements for RMn 2O 5 showed an antiferromagnetic transition. The strong irreversibility between the ZFC and FC curves indicated a helicoidally magnetic structure below 40 K. The max d.c. susceptibilities of LaMn 2O 5+δ ( δ=0.01, 0.06, 0.08, 0.16, 0.17) were found to be variable and the excess oxygen ( δ) in the compounds was influenced by the alkalinity used in the hydrothermal synthesis.

  11. Hydrothermal Synthesis of RbLn2F7 and VUV Spectroscopy of RbLn2F7:Eu3+(Ln=Gd, Y)

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    RbLn2F7 (Ln=Gd, Y, Er, Yb and Lu), crystallized in the hexagonal RbEr2F7 structure type, is synthesized by a hydrothermal method. The excitation spectra of Eu3+-doped RbGd(Y)2F7 suggest that the oxygen content is very low in the samples obtained by hydrothermal synthesis. Only the f-f transitions of Gd3+ ions are observed in the excitation spectrum of RbGd2F7:Eu3+ (0.5mol%), while those of Eu3+ ions do not appear. When the Gd3+ ions are excited, the absorbed energy is transferred efficiently from Gd3+ to Eu3+. The spectra show that the doped Eu3+ ions are located in non-centrosymmetric sites in hexagonal RbLn2F7.

  12. The deep structure of a sea-floor hydrothermal deposit

    Science.gov (United States)

    Zierenberg, R.A.; Fouquet, Y.; Miller, D.J.; Bahr, J.M.; Baker, P.A.; Bjerkgard, T.; Brunner, C.A.; Duckworth, R.C.; Gable, R.; Gieskes, J.; Goodfellow, W.D.; Groschel-Becker, H. M.; Guerin, G.; Ishibashi, J.; Iturrino, G.; James, R.H.; Lackschewitz, K.S.; Marquez, L.L.; Nehlig, P.; Peter, J.M.; Rigsby, C.A.; Schultheiss, P.; Shanks, Wayne C.; Simoneit, B.R.T.; Summit, M.; Teagle, D.A.H.; Urbat, M.; Zuffa, G.G.

    1998-01-01

    Hydrothermal circulation at the crests of mid-ocean ridges plays an important role in transferring heat from the interior of the Earth. A consequence of this hydrothermal circulation is the formation of metallic ore bodies known as volcanic-associated massive sulphide deposits. Such deposits, preserved on land, were important sources of copper for ancient civilizations and continue to provide a significant source of base metals (for example, copper and zinc). Here we present results from Ocean Drilling Program Leg 169, which drilled through a massive sulphide deposit on the northern Juan de Fuca spreading centre and penetrated the hydrothermal feeder zone through which the metal-rich fluids reached the sea floor. We found that the style of feeder-zone mineralization changes with depth in response to changes in the pore pressure of the hydrothermal fluids and discovered a stratified zone of high-grade copper-rich replacement mineralization below the massive sulphide deposit. This copper-rich zone represents a type of mineralization not previously observed below sea-floor deposits, and may provide new targets for land-based mineral exploration.

  13. Hydrothermal synthesis of two photoluminescent nitrogen-doped graphene quantum dots emitted green and khaki luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Xiaohua; Zuo, Xiaoxi; Hu, Ruiping; Xiao, Xin; Liang, Yong; Nan, Junmin, E-mail: jmnan@scnu.edu.cn

    2014-10-15

    A simple and effective chemical synthesis of the photoluminescent nitrogen-doped graphene quantum dots (N-GQDs) biomaterial is reported. Using the hydrothermal treatment of graphene oxide (GO) in the presence of hydrogen peroxide (H{sub 2}O{sub 2}) and ammonia, the N-GQDs are synthesized through H{sub 2}O{sub 2} exfoliating the GO into nanocrystals with lateral dimensions and ammonia passivating the generated active surface. Then, after a dialytic separation, two water-soluble N-GQDs with average size of about 2.1 nm/6.2 nm, which emit green/khaki luminescence and exhibit excitation dependent/independent photoluminescence (PL) behaviors, are obtained. In addition, it is also demonstrated that these two N-GQDs are stable over a broad pH range and have the upconversion PL property, showing this approach provides a simple and effective method to synthesize the functional N-GQDs. - Highlights: • Nitrogen-doped graphene quantum dots (N-GQDs) are prepared by hydrothermal routine. • Two N-GQDs with different size distribution emit green/khaki photoluminescence. • Two N-GQDs exhibit excitation-dependent/independent photoluminescence behaviors.

  14. Gelatin-assisted hydrothermal synthesis of single crystalline zinc oxide nanostars and their photocatalytic properties.

    Science.gov (United States)

    Fang, Ke-Ming; Wang, Zhen-Zhen; Zhang, Ming; Wang, Ai-Jun; Meng, Zi-Yan; Feng, Jiu-Ju

    2013-07-15

    Biotemplate-assisted approach is simple and friendly to the environment. With the assistance of gelatin as a soft biotemplate and a structure-directing agent, star-like zinc oxide (ZnO) nanostructures have been prepared by assembly of well-defined nanorods under hydrothermal conditions. Their morphology and structures were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The growth mechanism of the ZnO nanostars is also investigated. The as-prepared ZnO nanostars display high photocatalytic activity toward the degradation of methyl orange (MO) under ultraviolet (UV) irradiation.

  15. Synthesis and Electrochemical Performance of LiMnPO4 by Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Daichi Fujimoto

    2014-01-01

    Full Text Available LiMnPO4 with olivinestructure which is the promising candidate for high voltage cathode material was synthesized by hydrothermal method. In order to synthesize high purity and well-defined LiMnPO4, several precursors for Li, Mn, and P sources and hydrothermal reaction parameters including temperature and [H2O]/[Mn] value are optimized. By analyzing the structure, Mn valence, morphology, and chemical ratio via XRD, XPS, Raman, SEM, and ICP LiMnPO4 synthesized from manganese acetate tetrahydrate have single phase of LiMnPO4 without impurity and showed charge and discharge reaction caused by Mn2+/Mn3+ redox. Specific capacity of synthesized LiMnPO4 grew up during cycling. Moreover, when hydrothermal temperature was set at 150°C and [H2O]/[Mn] value was set at 15, discharge capacity as high as 70 mAh/g was obtained at 1/20  C rate.

  16. Synthesis and electrochemical performance of Ti3C2Tx with hydrothermal process

    Science.gov (United States)

    Wang, Libo; Zhang, Heng; Wang, Bo; Shen, Changjie; Zhang, Chuanxiang; Hu, Qianku; Zhou, Aiguo; Liu, Baozhong

    2016-09-01

    In this study, a simple hydrothermal method has been developed to prepare Ti3C2Tx from Ti3AlC2 as a high-performance electrode material for supercapacitors. This method is environmentally friendly and has a low level of danger. The morphology and structure of the Ti3C2Tx can be controlled by hydrothermal reaction time, temperature and NH4F amounts. The prepared Ti3C2Tx was characterized by X-ray diffraction, field emission scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and Brunauer-Emmet-Teller. The results show that the prepared Ti3C2Tx is terminated by O, OH, and F groups. The electrochemical properties of the Ti3C2Tx sample exhibit specific capacitance up to 141 Fcm-3 in 3 M KOH aqueous electrolyte, and even after 1000 cycles, no significant degradation of the volumetric capacitance was observed. These results indicate that the Ti3C2Tx material prepared by this hydrothermal method can be used in high performance supercapacitors.

  17. Hydrothermal synthesis and properties of controlled α-Fe2O3 nanostructures in HEPES solution.

    Science.gov (United States)

    Li, Hui; Lu, Zhong; Li, Qin; So, Man-Ho; Che, Chi-Ming; Chen, Rong

    2011-09-05

    A facile, template-free, and environmentally friendly hydrothermal strategy was explored for the controllable synthesis of α-Fe(2)O(3) nanostructures in HEPES solution (HEPES=2-[4-(2-hydroxyethyl)-1-piperazinyl]ethanesulfonic acid). The effects of experimental parameters including HEPES/FeCl(3) molar ratio, pH value, reaction temperature, and reaction time on the formation of α-Fe(2)O(3) nanostructures have been investigated systematically. Based on the observations of the products, the function of HEPES in the reaction is discussed. The different α-Fe(2)O(3) nanostructures possess different optical, magnetic properties, and photocatalytic activities, depending on the shape and size of the sample. In addition, a novel and facile approach was developed for the synthesis of Au/α-Fe(2)O(3) and Ag/α-Fe(2)O(3) nanocomposites in HEPES buffer solution; this verified the dual function of HEPES both as reductant and stabilizer. This work provides a new strategy for the controllable synthesis of transition metal oxide nanostructures and metal-supported nanocomposites, and gives a strong evidence of the relationship between the property and morphology/size of nanomaterials.

  18. Evidence for a spatially extensive hydrothermal system at the Ries impact structure, Germany

    Science.gov (United States)

    Sapers, H. M.; Osinski, G. R.; Flemming, R. L.; Buitenhuis, E.; Banerjee, N. R.; Tornabene, L. L.; Blain, S.; Hainge, J.

    2017-02-01

    The 15 Ma, 26 km diameter Ries impact structure in south-central Germany was one of the first terrestrial impact structures where evidence of impact-associated hydrothermal alteration was recognized. Previous studies suggested that pervasive, high-temperature hydrothermal activity was restricted to the area within the "inner ring" (i.e., the crater-fill impactite units). Here we present mineralogical evidence for localized hydrothermal activity in the ejecta beyond the crater rim in two previously unstudied settings: a pervasively altered lens of suevite ejecta directly overlying the Bunte Breccia at the Aumühle quarry; and suevite ejecta at depth overlain by 20 m of lacustrine sediments sampled by the Wörnitzostheim 1965 drill core. A comprehensive set of X-ray diffraction analyses indicates five distinct alteration regimes (1) surficial ambient weathering characterized by smectite and a minor illitic component; (2) locally restricted hydrothermal activity characterized by an illitic component and minor smectite; (3) hydrothermal activity at depth characterized by smectite, a minor illitic component, and calcite; (4) hydrothermal activity at depth characterized by smectite, a minor illitic component, calcite, zeolites, and clinochlore; and (5) pervasive hydrothermal activity at depth characterized by smectite, a minor illitic component, and minor clinochlore. These data spatially extend the Ries postimpact hydrothermal system suggesting a much more extensive, complex, and dynamic system than previously thought. Constraining the mineralogical alteration regimes at the Ries impact structure may also further our understanding of impact-associated phyllosilicate formation on Mars with implications for climate models and habitability.

  19. Synthesis and characterization of zeolite A by hydrothermal transformation of natural Jordanian kaolin

    Directory of Open Access Journals (Sweden)

    Mousa Gougazeh

    2014-04-01

    Full Text Available The synthesis of zeolite materials by hydrothermal transformation of natural Jordanian kaolin in NaOH solutions of various concentrations was investigated at 100 °C for 20 h. A mixture of zeolite A, quartz and hydroxysodalite (HS was obtained. Zeolite A was the main product with the NaOH concentrations of 1.50–3.50 M, which was confirmed by XRD, IR and SEM. Zeolite A can be obtained from natural kaolin under the conditions applied showing that metakaolinization can be observed at 650 °C which is much lower than the temperatures given in the previous works, 700–950 °C. The products obtained from the experiments were characterized by X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FTIR and scanning electron microscopy (SEM.

  20. Synthesis and Electronic Transport of Hydrothermally Synthesized p-Type Na-Doped SnSe

    Science.gov (United States)

    Yang, Zong-Ren; Chen, Wei-Hao; Liu, Chia-Jyi

    2016-11-01

    A series of polycrystalline Sn1-x Na x Se with x = 0.00, 0.02, 0.04 and 0.10 were fabricated using hydrothermal synthesis followed by evacuated-and-encapsulated sintering. The as-fabricated materials were characterized using powder x-ray diffraction and electronic transport. The resulting materials were single phase. Partial replacement of Na for Sn leads to a simultaneous increase of electrical conductivity and thermopower. The x = 0.04 sample has the largest power factor among the series of the samples. Upon partial replacement of Na for Sn, the power factor is significantly enhanced as compared to the undoped SnSe. The maximum ZT value of ˜0.4 was achieved for Sn0.96Na0.04Se at 550 K.

  1. Eu{sup 3+} doped lanthanum oxide nanowhiskers: microwave hydrothermal synthesis, characterization and photoluminescence properties

    Energy Technology Data Exchange (ETDEWEB)

    Murugan, A Vadivel [Photonics and Advanced Materials Group, Centre for Materials for Electronics Technology (C-MET), Panchawati, Off-Pashan Road, Pune-411008 (India); Viswanath, Annamraju Kasi [Photonics and Advanced Materials Group, Centre for Materials for Electronics Technology (C-MET), Panchawati, Off-Pashan Road, Pune-411008 (India); Kakade, Bhalchandra A [Physical and Materials Chemistry Division, National Chemical Laboratory, Pune-411008 (India); Ravi, V [Physical and Materials Chemistry Division, National Chemical Laboratory, Pune-411008 (India); Saaminathan, V [Faculty of Engineering, Multimedia University, Jalan Multimedia, Cyber Jaya Campus, Cyberjaya, Selangor, DE 63100 (Malaysia)

    2006-09-21

    We report here a straightforward and rapid microwave-hydrothermal route providing an easy synthesis of Eu{sup 3+} doped La{sub 2}O{sub 3} nanowhiskers. The nanostructured Eu{sup 3+} doped La{sub 2}O{sub 3} is characterized by x-ray diffraction studies, scanning electron microscopy and photoluminescence (PL). The emission spectrum shows transitions from the excited 5D{sub 0} state to {sup 7}F{sub J} (J 0, 1, 2, 3, 4) levels of the Eu{sup 3+} ion. The most intense peak around 611 nm is due to the {sup 5}D{sub 0} {yields} {sup 7}F{sub 2} transition, expected from the Judd-Ofelt selection rules. PL spectra measurements demonstrate that the lanthanum oxide nanowhisker shows higher PL intensity.

  2. Hydrothermal synthesis of TiO2/WO3 compositions and their photocatalytic activity

    Science.gov (United States)

    Pyachin, Sergey A.; Karpovich, Natalia F.; Zaitsev, Alexey V.; Makarevich, Konstantin S.; Burkov, Alexander A.; Ustinov, Alexander Yu.

    2016-11-01

    Photocatalytic activity, optical properties, thermal stability, phase patterns and morphology of nano-size TiO2/WO3 compositions obtained from organic precursors through hydrothermal synthesis have been studied. It has been shown that doping of anatase nanoparticles with tungsten W+6 results in particle diameter reduction from 35 to 10 nm; decrease in width of the band gap from 3.15 eV to 2.91 eV and increase in temperature of phase transition of anatase to rutile up to 980oC. Catalytic activity of TiO2/WO3 (4 mol.%) composition under photochemical methylene blue (MB) oxidation by simulated solar light exceeds that of undoped anatase (obtained in the same way) 6-fold.

  3. Hydrothermal synthesis of Ni(12)P(5) hollow microspheres, characterization and photocatalytic degradation property.

    Science.gov (United States)

    Li, Jun; Ni, Yonghong; Liao, Kaiming; Hong, Jianming

    2009-04-01

    In this paper, we report the successful synthesis of Ni(12)P(5) hollow spheres via a facile hydrothermal route, employing white phosphorus (WP) and nickel nitrate as the reactants in the presence of hexamethylenetetramine (HMT) and polyethylene glycol 10000 (PEG-10000). The phase and morphology of the product were characterized by means of powder X-ray diffraction (XRD), energy dispersive spectrometry (EDS), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). HMT and surfactant (PEG-10000) played important roles in the formation of Ni(12)P(5) hollow microspheres. Furthermore, research also showed that the as-prepared Ni(12)P(5) hollow spheres could photocatalytically degrade some organic dyes such as Safranine T and Pyronine B under irradiation of 365 nm UV light.

  4. Hydrothermal Synthesis of Pure r-Phase Manganese(II) Sulfide without the Use of Organic Reagents

    Energy Technology Data Exchange (ETDEWEB)

    Michel, F.M.; Schoonen, M.A.A.; Zhang, X.V.; Martin, S.T.; Parise, J.B. (SBU); (Harvard)

    2008-06-18

    Recent studies exploring the role of metal sulfides as (photo)catalysts in prebiotic synthesis reactions provide the impetus for finding carbon-free synthesis methods for metal sulfides. The decomposition of organosulfur and organometallic precursor compounds is often the protocol for synthesizing bulk metal chalcogenides, such as manganese sulfide (MnS). Here we report a hydrothermal synthesis method for the formation of MnS in which a MnCl{sub 2} solution is injected into a preheated sulfide solution. By varying the temperature of injection and subsequent aging time, we can control the specific crystal phase of the product. Three MnS polymorphs are known, and two of these, {alpha}-MnS and {gamma}-MnS, form as pure phases in aqueous systems. The initial precipitate formed upon mixing of aqueous solutions of Mn{sup 2+} and S{sup 2-} at ambient temperature is nanocrystalline and is composed of a mixture of {gamma}-MnS (wurtzite structure) and {beta}-MnS (zinc blende structure). {beta}-MnS has not previously been identified as forming under aqueous conditions. The initial binary-phase precipitate can be transformed to pure, highly crystalline {gamma}-MnS by aging at temperatures as low as 150 C within 3 days. Aging to yield pure {alpha}-MnS requires temperatures in excess of 200 C for 3 days. Characterization of the products was performed using powder X-ray diffraction, total scattering and pair distribution function analysis, dynamic light scattering, and transmission and scanning electron microscopy. Chemical analyses were performed using colorimetric techniques.

  5. Hydrothermal synthesis of hydrocarbons at low temperature. Implications for sustaining a biosphere in Europa

    Science.gov (United States)

    Navarro-Gonzalez, Rafael; Montoya, Lilia; Davis, Wanda; McKay, Chris

    Observational evidence from Earth-borne systems and space missions as well as theoretical arguments suggest that Jupiter's satellite Europa could be geologically active today and may possess an ocean of liquid water of about 100 km deep underneath the icy surface about 10 km thickness. The existence of an aqueous ocean is an important requirement for life, as we know it. However, a biosphere also depends of an adequate energy source to drive the most fundamental biological processes such as metabolism, growth, reproduction, etc. Methanogenesis associated with hydrothermal vents may potentially drive a biosphere in an European ocean. We report here on the production of a large variety of hydrocarbons in hydrothermal systems at low temperatures (150° C). The chemical composition of the hydrothermal vent gases was derived from a thermochemical model that assumes that Europa had a cometary (solar, less H) abundance at high temperatures characteristic of a vent. Specifically the following gas mixture was used: 45% CO2 , 45% CH4, and 10 % N2 . A 500 ml stainless steel reactor was filled with 200 ml triply distilled water and the gas mixture at 1 bar at 25° C. In some experiments 3 g of pyrite were added into the reaction vessel. The system was heated for 24 hrs in the temperature range from 100 to 375° C. At the completion of the experiment, the reaction was quenched to 25° C and the gas mixture was analyzed by GC-FTIR-MS techniques. In the absence of pyrite, methane is oxidized to carbon dioxide with the possible production of hydrogen. In contrast in the presence of pyrite, methane is converted into a suite of hydrocarbons from C2 to C7 containing all possible isomers. The production of these compounds was found at temperatures as low as 150° C. In order to get a better understanding of the chemical mechanism involved in the synthesis of hydrocarbons and explore the effect on the initial oxidation state of the carbon used, we performed additional experiments in

  6. Controlled hydrothermal synthesis of CeO{sub 2} nanospheres and their excellent magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Xiaofei [Suzhou University, Anhui Key Laboratory of Spintronics and Nanomaterials Research, Suzhou, Anhui (China)

    2017-04-15

    Monodisperse spherical CeO{sub 2} nanostructures with irregular and rough surfaces have successfully been synthesized via a facile hydrothermal technology. XRD, SEM, XPS, Raman scattering, and M-H curves were employed to characterize the samples. The results showed that the spherical CeO{sub 2} nanostructures have a cubic fluorite structure and that there are Ce{sup 3+} ions and oxygen vacancies in the surface of the samples. The M-H curve of CeO{sub 2} nanospheres exhibits excellent room-temperature ferromagnetism (RT-FM), which is likely ascribed to the effects of the Ce{sup 3+} ions and oxygen vacancies. (orig.)

  7. Direct hydrothermal synthesis and magnetic property of titanate nanotubes doped magnetic metal ions

    Institute of Scientific and Technical Information of China (English)

    Meili Wang; Gongbao Song; Jian Li; Landong Miao; Baoshu Zhang

    2008-01-01

    Pure titanate nanotubes and titanate nanotubes doped with Fe3+/Ni2+/Mn2+ ions were synthesized by the hydrothermal method. In this process, titanate nanotubes were first prepared synchronously with doping Fe3+/Ni2+/Mn2+ ions. The morphology,structure, thermal stability and magnetic property of titanate nanotubes were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), and magnetic measurement. The titanate nanotubes transformed into the anatase titania nanocrystals,and further the mixture of anatase and rutile titania along with increasing temperature. The results indicate that the titanate nanotubes doped with Fe3+/Ni2+/Mn2+ ions are paramagnetic behaviors.

  8. Hydrothermal synthesis of micrometer sized HgMoO{sub 4} flowers formed by nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Jia Runping, E-mail: jiarp@sit.edu.cn; Zhang Yingqiang, E-mail: sh_yqzhang@sina.co [Shanghai Institute of Technology, School of Materials Science and Engineering (China)

    2010-10-15

    Micrometer sized HgMoO{sub 4} flowers formed by nanorods were prepared by a selected hydrothermal method using a mixture of ethanol and water as a reaction medium, which were characterized by scanning electron microscopy, X-ray diffractometer (XRD), FT-IR spectrometry, photoluminescence spectrometry, and UV-visible spectrometry. Results indicated that the micrometer sized flowers consisted of mercury molybdate nanorods, and the monoclinic wolframite-type structure of the flowers was confirmed by both XRD and FT-IR spectrometry. A blue shift of the photoluminescence peaks and a broadening of XRD peaks were observed, which increased with ethanol fraction in the reaction medium.

  9. Hydrothermal Synthesis and Characterization of Inorganic /Organic Hybrid Complex Containing Tungstophsphate

    Institute of Scientific and Technical Information of China (English)

    JIN Su-rong; ZHANG Lian-meng; LIU Shi-zhong; ZHAO Wei-feng

    2004-01-01

    A new complex [Cu(C12H8N2)2]1.5PW12O40·1.5H2O was synthesized under hydrothermal conditions. The complex was characterized by the elemental analysis, SEM, X-ray powder diffraction analysis, IR,UV-Vis spectroscopy,and TG thermal analysis,respectively. The experimental result shows that the heteropolyanion is of a Keggin structure containing coordinated cations. Photochromism studies show that the electron transfer takes place from the organic compound to the heteropolyanion.

  10. Photocatalytic activity of Li-doped TiO{sub 2} nanoparticles: Synthesis via ionic liquid-assisted hydrothermal route

    Energy Technology Data Exchange (ETDEWEB)

    Ravishankar, T.N. [Centre for Nano and Material Sciences, Jain University, Jakkasandra, Kanakapura (T) (India); Nagaraju, G., E-mail: nagarajugn@rediffmail.com [Centre for Nano and Material Sciences, Jain University, Jakkasandra, Kanakapura (T) (India); Department of Chemistry, Siddaganga Institute of Technology, Tumkur, Karnataka (India); Dupont, Jairton [School of Chemistry, University of Nottingham, University Park, NG7 2RD Nottingham (United Kingdom)

    2016-06-15

    Highlights: • TiO{sub 2}: Li nanoparticles were synthesized via an ionic liquid-assisted hydrothermal method. • The doping of Li to anatase TiO{sub 2} affects the properties of the resultant product. • TiO{sub 2}: Li nanoparticles were used as a photocatalyst for the degradation of dye. • TiO{sub 2}: Li nanoparticles were used as sensor, and antibacterial agent. • TiO{sub 2}: Li were used as reducing agent for the reduction of Cr{sup 6+} to Cr{sup 3+}. - Abstract: We have proposed a simple one pot synthesis of lithium-doped TiO{sub 2} nanoparticles (TiO{sub 2}:Li) via an ionic liquid-assisted hydrothermal method and their potential use as a photocatalyst for the degradation of organic dye, as well as the reduction of toxic Cr{sup 6+} to non toxic Cr{sup 3+}. The structure of TiO{sub 2}:Li nanoparticles was examined by XRD, FTIR, XPS, Raman, UV–vis, Photoluminescence spectroscopy and morphology by SEM and TEM. The incorporation of Li into anatase-phase TiO{sub 2} affected the optical properties of the resultant TiO{sub 2} nanoparticles. The photocatalytic activity of the TiO{sub 2}:Li nanoparticles was determined by degradation of trypan blue. Degradation studies showed improved photocatalytic activity of TiO{sub 2}:Li nanoparticles compared to TiO{sub 2} nanoparticles and bulk TiO{sub 2}. TiO{sub 2}:Li nanoparticles also functioned as a detoxification agent which was confirmed by the reduction of Cr{sup 6+} to Cr{sup 3+}.

  11. Structural analysis of ZnO nanowires synthesized by using a low-temperature hydro-thermal method

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Hyo; Lee, Jun Seok; Ko, Won Bae; Kang, Tae Seong; Hong, Jin Pyo [Hanyang University, Seoul (Korea, Republic of); Cha, Seung Nam [Samsung Institute of Advanced Technology, Yongin (Korea, Republic of)

    2012-05-15

    The structural properties of vertically aligned ZnO nanowires (NWs) prepared using hydrothermal synthesis at various temperatures and different precursor concentrations are systematically described. The ZnO NWs were synthesized on ZnO seed layers via an aqueous solution method with zinc nitrate (Zn(NO{sub 3}){sub 2}·6H{sub 2}O) hexahydrate and hexamethylenetetramine (HMT). The growth speed and the shape of the ZnO NWs were determined for various mole concentrations. A structural analysis of the ZnO NWs was performed using X-ray diffraction, scanning electron microscopy and tunneling electron microscopy. Finally, the correlation of structural results with growth conditions, such as the mole concentration and the growth temperature of chemical precursors, based on Gibbs free energy.

  12. Hydrothermal Synthesis and Crystal Structure of a New Zero-dimensional Complex: [Zn(H2BPTC)(phen)2]n·3nH2O

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A new metal-organic coordination complex [Zn(H2BPTC)(phen)2]n·3nH2O (BPTC =3,3',4,4'-benzophenone tetracarboxylate, phen = 1,10-phenanthroline) 1 has been obtained from hydrothermal reaction and characterized by elemental analysis, IR, TG and single-crystal X-ray diffraction. In compound 1, the zinc cation is hexa-coordinated with two carboxylate oxygen atoms from one H2BPTC ligand and four nitrogen atoms from two different phen ligands, showing a slightly distorted octahedral geometry. Crystal data: C41H30N4O12Zn, Mr = 836.06, monoclinic,P21/c, a = 14.2714(9), b = 16.9386(10), c = 15.0151(9) (A),β = 101.3420(10)°, V= 3558.8(4) (A)3, Dc= 1.560 g/cm3,μ(MoKα) = 0.766 mm-1, F(000) = 1720, Z = 4, R = 0.0439 and wR = 0.1157 for 4123observed reflections with I > 2σ(I).

  13. Hydrothermal synthesis, characterization by single crystal XRD, structural discussion and electric, dielectrical properties of (C6H9N2)2(Hg0.12Zn0.88)Cl4 hybrid compound

    Science.gov (United States)

    Elwej, R.; Hlel, F.

    2016-10-01

    The new hybrid compound "Bis-2-amino-4-picolinium tetrachloro-mercurate-zincate ((C6H9N2)2(Hg0.12Zn0.88)Cl4)" was prepared by hydrothermal method using HCl as solvent and characterized by XRD, NMR-MAS 13C and electrical impedance spectroscopy. The XRD reveals that the compound was crystallized in the triclinic system, centrosymetric space group P 1 bar and the lattice parameters a=7.578(1)Å, b=8.559(1)Å, c=15.418(2)Å, α=84.443(1)°, β=89.506(1)°, γ=68.615(1)° and Z=2. The AC electrical conductivity and the dielectric relaxation properties were measured in the frequency range of 209 Hz-5 MHz at different temperature. The alternating current (AC) conductivity of the investigated compound obeys the Jonscher law: σ(ω)=σdc+Aωn. Furthermore, the temperature dependence of the Jonscher's exponent shows that the conduction inside the studied material is insured by the model: overlapping-large polaron tunneling (OLPT) model.

  14. Hydrothermal synthesis and crystal structure study of two novel 3-D mellitates {Nd2[C6(COO)6](H2O)6} and {Ho2[C6(COO)6](H2O)6}

    Institute of Scientific and Technical Information of China (English)

    TANG Xiaoyong; YUE Shantang; LI Ping; WANG Ning; LIU Yingliang

    2008-01-01

    Two novel 3-D coordination compounds, Nd2[C6(COO)6](H2O)6(1)and Ho2[C6(COO)6](H2O)6(2), were hydrothermally synthe-sized from mellitic acid and neodymium perchlorate (or holmium perchlorate) in the alkaline aqueous solution and characterized with ele-mental analysis, TG, IR spectrum, and single crystal X-ray diffraction. The two compounds were isostructural and crystallized in the ortho-rhombic system, space group Pnnm, with a=1.3531 (4) nm, b=0.6687 (2) nm, c=1.0224(3) nm, V=0.92523(5) nm3, Z=4, D=2.630 g/cm3, F(000)=696.0, Goof=1.052. Final R indices [I 2Σ(I)]: R1=0.0195, wR2=0.0382 for 1; a=1.3411(2) nm, b=0.6586(1) nm, c=1.0116(2) nm, V=0.8935(3) nm3, Z=4, D=2.877 g/cm3, F(000)=724.0, Goof=1.061. Final R indices [I 2Σ(I)]: R1=0.0200, wR2=0.0479 for 2. In the two compounds 1 and 2, the mellitic acid ligand, in which all the carboxylate groups were deprotonated, had only one kind of coordination mode to bridge metal ions to form four-connected three-dimensional diamondiod networks.

  15. The use of hydrothermal methods in the synthesis of novel open-framework materials

    Indian Academy of Sciences (India)

    Srinivasan Natarajan; Sukhendu Mandal; Partha Mahata; Vandavasi Koteswara Rao; Padmini Ramaswamy; Abhishek Banerjee; Avijit Kumar Paul; K V Ramya

    2006-11-01

    The preparation of inorganic compounds, exhibiting open-framework structures, by hydrothermal methods has been presented. To illustrate the efficacy of this approach, few select examples encompassing a wide variety and diversity in the structures have been provided. In all the cases, good quality single crystals were obtained, which were used for the elucidation of the structure. In the first example, simple inorganic network compounds based on phosphite and arsenate are described. In the second example, inorganic-organic hybrid compounds involving phosphite/arsenate along with oxalate units are presented. In the third example, new coordination polymers with interesting structures are given. The examples presented are representative of the type and variety of compounds one can prepare by careful choice of the reaction conditions.

  16. Hydrothermal synthesis of N-doped spherical carbon from carboxymethylcellulose for CO2 capture

    Science.gov (United States)

    Wu, Qiong; Li, Wei; Liu, Shouxin; Jin, Chunde

    2016-04-01

    Spherical carbonaceous adsorbents (CSn) with micro-porosity developed for CO2 capture were prepared by a simple hydrothermal carbonization of carboxymethylcellulose (CMC) in the presence of urea, and activated in a high temperature N2 atmosphere. The effects of specific surface area, pore structure, and N content on the CO2 adsorption capacity were systematically investigated. Urea was found to react with surface carbonyl groups and other intermediate products generated by CMC hydrothermal carbonization, which produced highly spherical morphologies that also exhibited some ordered lattice structures. The particle size of N-doped CSn was larger than that of particles prepared without urea. Nitrogen was mainly present in pyridine (N-6), pyrrolic/pyridone (N-5) and quaternary (N-Q) forms. The high CO2 capture capacity was produced by a combination of N-doping and developing micro-pore structures. At an adsorption pressure of 1 bar, the capacity was dominated by the micro-porosity. However, during initial, lower pressures the N content dominated the CO2 adsorption capacity.

  17. Optimization of hydrothermal synthesis of pure phase zeolite Na-P1 from South African coal fly ashes.

    Science.gov (United States)

    Musyoka, Nicholas M; Petrik, Leslie F; Gitari, Wilson M; Balfour, Gillian; Hums, Eric

    2012-01-01

    This study was aimed at optimizing the synthesis conditions for pure phase zeolite Na-P1 from three coal fly ashes obtained from power stations in the Mpumalanga province of South Africa. Synthesis variables evaluated were: hydrothermal treatment time (12-48 hours), temperature (100-160°C) and varying molar quantities of water during the hydrothermal treatment step (H(2)O:SiO(2) molar ratio ranged between 0-0.49). The optimum synthesis conditions for preparing pure phase zeolite Na-P1 were achieved when the molar regime was 1 SiO(2): 0.36 Al(2)O(3): 0.59 NaOH: 0.49 H(2)O and ageing was done at 47°C for 48 hours. The optimum hydrothermal treatment time and temperature was 48 hours and 140°C, respectively. Fly ashes sourced from two coal-fired power plants (A, B) were found to produce nearly same high purity zeolite Na-P1 under identical conditions whereas the third fly ash (C) lead to a low quality zeolite Na-P1 under these conditions. The cation exchange capacity for the high pure phase was found to be 4.11 meq/g. These results highlight the fact that adjustment of reactant composition and presynthesis or synthesis parameters, improved quality of zeolite Na-P1 can be achieved and hence an improved potential for application of zeolites prepared from coal fly ash.

  18. The hydrothermal synthesis of hydrotalcite by using different partially soluble and insoluble in water mangesium and aluminium components

    Directory of Open Access Journals (Sweden)

    Bankauskaite A.

    2011-01-01

    Full Text Available In this work, the influence of different partially soluble and insoluble in water Mg and Al components on the formation of hydrotalcite by using only hydrothermal synthesis was examined. Hydrothermal synthesis duration was 4, 24 and 72 h at 200°C and Mg/Al ratio was equal to 3:1. The starting materials were: 4MgCO3•Mg(OH2•5H2O, Mg5(CO34•(OH2•4H2O, Al(OH3 and γ-Al2O3. It was determined that Mg and Al containing compounds have most important influence on the formation of hydrotalcite by hydrothermal conditions. 4MgCO3⋅Mg(OH2⋅5H2O as raw material is not recommendable for the synthesis of hydrotalcite, because even after 24 h of isothermal curing at 200°C temperature hydrotalcite is not formed and magnesium aluminum hydroxide hydrate is dominant in the synthesis products. Besides, initial magnesium containing component is decomposed into magnesium carbonate and hydroxide. It was examined that hydrotalcite is formed already after 4 h of hydrothermal synthesis at 200°C temperature when Mg/Al molar ratio is equal to 3:1 in the Mg5(CO34•(OH2•4H2O - γ-Al2O3/ Al(OH3 - H2O system. However, together with this compound a fair amount of an intermediate compounds (boehmite and magnesium carbonate are formed. The duration of isothermal curing determines the formation of a hexagonal plates which are characteristic to hydrotalcite.

  19. Synthesis of flower-like Boehmite (γ-AlOOH) via a one-step ionic liquid-assisted hydrothermal route

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Zhe, E-mail: tangzhe1983@163.com; Liang, Jilei, E-mail: liangjilei_httplan@126.com; Li, Xuehui, E-mail: lxhhmx@163.com; Li, Jingfeng, E-mail: dzcljf@126.com; Guo, Hailing; Liu, Yunqi, E-mail: liuyq@upc.edu.cn; Liu, Chenguang, E-mail: cgliu@upc.edu.cn

    2013-06-01

    A simple and novel synthesis process, one-step ionic liquid-assisted hydrothermal synthesis route, has been developed in the work to synthesize Bohemithe (γ-AlOOH) with flower-like structure. The samples were characterized by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR) and Scanning Electron Microscope (SEM). Ionic liquid [Omim]{sup +}Cl{sup −}, as a template, plays an important role in the morphology and pore structure of the products due to its strong interactions with reaction particles. With the increase in the dosage of ionic liquid [Omim]{sup +}Cl{sup −}, the morphology of the γ-AlOOH was changed from initial bundles of nanosheets (without ionic liquid) into final well-developed monodispersed 3D flower-like architectures ([Omim]{sup +}Cl{sup −}=72 mmol). The pore structure was also altered gradually from initial disordered slit-like pore into final relatively ordered ink-bottle pore. Furthermore, the proposed formation mechanism and other influencing factors such as reaction temperature and urea on formation and morphology of the γ-AlOOH have also been investigated. - Graphical abstract: The flower-like γ-AlOOH architectures composed by nanosheets with narrow size distribution (1.6–2.2 μm) and uniform pore size (6.92 nm) have been synthesized via a one-step ionic liquid-assisted hydrothermal route. - Highlights: • The γ-AlOOH microflowers were synthesized via an ionic liquid-assisted hydrothermal route. • Ionic liquid plays an important role on the morphology and porous structure of the products. • Ionic liquid can be easily removed from the products and reused in recycling experiments. • A “aggregation–recrystallization–Ostwald Ripening“formation mechanism may occur.

  20. Hydrothermal synthesis of graphene-LaFeO3 composite supported with Cu-Co nanocatalyst for higher alcohol synthesis from syngas

    Science.gov (United States)

    Niu, T.; Liu, G. L.; Chen, Y.; Yang, J.; Wu, Jiang; Cao, Y.; Liu, Y.

    2016-02-01

    The composite of graphene and a perovskite-type oxide (PTO) should be an attractive new material, owing to the special properties of graphene and the flexibility of PTO. Both graphene and PTO are promising support for some metallic nanoparticles. Therefore, in this work, taking LaFeO3 as the representative for PTO, a novel composite of graphene sheets-LaFeO3 has been prepared by using hydrothermal synthesis, and bimetallic nanoparticles of Cu-Co have been loaded on the composite. The resultant catalyst is applied to higher alcohols synthesis (HAS) from syngas. The morphology, structure and the state of the bimetallic composite catalyst are characterized by using techniques of SEM, TEM, AFM, XRD, TPR, Raman and N2 adsorption-desorption. For the graphene-LaFeO3 support, the graphene sheets are embedded into the bulk LaFeO3 or uniformly deposited on the surface of the LaFeO3 grains, resulting in high specific surface area. And the mass transferring ability of the bimetallic catalyst is optimized by uniform mixing of graphene and LaFeO3 and the formation of the mesopores. For the active component, the Cu-Co alloy nanoparticles are highly dispersed on the graphene-LaFeO3 composite, which leads to the high activity, high selectivity and excellent stability to higher alcohols.

  1. Hydrothermal Synthesis, Characterization, and Visible Light-Driven Photocatalytic Properties of Bi2WO6 Nanoplates

    Directory of Open Access Journals (Sweden)

    Anukorn Phuruangrat

    2014-01-01

    Full Text Available In this research, the effects on reaction temperature and length of time on Bi2WO6 nanoplates by hydrothermal synthesis on morphologies and photocatalytic properties were studied. The products obtained at different reaction temperature and reaction time were characterized by XRD, Raman, FTIR, SEM, and TEM techniques. The photocatalytic properties of the samples were measured by decomposing the rhodamine-B organic dye. XRD pattern was specified as pure orthorhombic well-crystallized Bi2WO6 phase for the 180°C and 20 h synthesis. Its FTIR spectrum shows main absorption bands at 400–1000 cm−1, assigned to Bi–O stretching, W–O stretching, and W–O–W bridging stretching modes. SEM and TEM analyses show that the product was composed of nanoplates. Photocatalytic activity of Bi2WO6 nanoplates shows the 98.24% degradation of rhodamine-B under the Xe light irradiation within 100 min.

  2. Structural characteristics and glucose response in mice of potato starch modified by hydrothermal treatments

    Science.gov (United States)

    The structural properties and digestibility of slowly digestible The structural properties and digestibility of slowly digestible hydrothermally treated potato starch (SDS) were investigated. The potato starch with 20, 30 or 40% moisture content was heated at 100 °C for 30 min, and then kept at 30 °...

  3. Morphological, structural and field emission characterization of hydrothermally synthesized MoS2-RGO nanocomposite

    Science.gov (United States)

    Bansode, Sanjeewani R.; Harpale, Kashmira; Khare, Ruchita T.; Walke, Pravin S.; More, Mahendra A.

    2016-11-01

    A few layered MoS2-RGO nanocomposite has been synthesized employing a facile hydrothermal synthesis route. The morphological and structural analysis performed using SEM, TEM, HRTEM and Raman spectroscopy clearly reveal formation of vertically aligned a few layer thick MoS2 sheets on RGO surface. Attempts have been made to reveal the influence of graphite oxide (GO) percentage on morphology of the nanocomposite. Furthermore, field emission (FE) investigations of as-synthesied MoS2-RGO nanocomposite are observed to be superior to the pristine MoS2 emitter. The values of turn-on field, defined at emission current density of 10 μA cm-2, are found to be 2.6 and 4.7 V μm-1 for the MoS2-RGO (5%) nanocomposite and pristine MoS2 emitters, respectively. The value of threshold field, defined at emission current density of 100 μA cm-2, is found to be 3.1 V μm-1 for MoS2-RGO nanocomposite. The emission current stability at the pre-set value of 1 μA over 3 h duration is found to be fairly good, characterized by current fluctuation within ±18% of the average value. The enhanced FE behavior for MoS2-RGO nanocomposite is attributed to a high enhancement factor (β) of 4128 and modulation of the electronic properties. The facile approach adopted herein can be extended to enhance various functionalities of other nanocomposites.

  4. Hydrothermal synthesis of rutile–anatase TiO{sub 2} nanobranched arrays for efficient dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Soon Jin; Im, Hyo Been [Graduate School of Energy Science and Technology, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764 (Korea, Republic of); Nam, Jung Eun; Kang, Jin Kyu [Advanced Convergence Research Center, Daegu Gyeongbuk Institute of Science and Technology (DGIST), 50-1, Sang-ri, Hyeonpung-myeon, Dalseong-gun, Daegu 711-873 (Korea, Republic of); Hwang, Taek Sung [Department of Chemical Engineering, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764 (Korea, Republic of); Yi, Kwang Bok, E-mail: cosy32@cnu.ac.kr [Department of Chemical Engineering Education, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764 (Korea, Republic of)

    2014-11-30

    Highlights: • The unique rutile–anatase TiO{sub 2} nanobranched arrays have been synthesized for DSSC application. • TiO{sub 2} nano-structure consists of anatase nanobranches covering of rutile nanorod surfaces. • The successful attachment of anatase TiO{sub 2} nanobranches to the nanorods is achieved by TiCl{sub 4} treatment. - Abstract: Rutile–anatase TiO{sub 2} nanobranched arrays were prepared in two sequential hydrothermal-synthesis steps. The morphologies and crystalline nanostructures of the samples were investigated by controlling growth time and the concentration of the titanium precursor. All samples were characterized by field-emission scanning electron microscopy and X-ray diffraction analysis. It was found that treating the surfaces of rutile TiO{sub 2} nanorods with aqueous TiCl{sub 4} solutions allows the anatase TiO{sub 2} nanobranches to grow perpendicular to the main rutile TiO{sub 2} nanorods attached to the FTO glass. Irregularly shaped, dense TiO{sub 2} structures formed in the absence of TiCl{sub 4} treatment. A light-to-electricity conversion efficiency of 3.45% was achieved using 2.3 μm tall TiO{sub 2} nanobranched arrays in a dye-sensitized solar cell. This value is significantly higher than that observed for pure rutile TiO{sub 2} nanorods.

  5. Synthesis of hydrothermally stable, hierarchically mesoporous aluminosilicate Al-SBA-1 and their catalytic properties

    Science.gov (United States)

    Li, Na; Wang, Jin-Gui; Xu, Jian-Xiong; Liu, Jin-Yu; Zhou, Hui-Jing; Sun, Ping-Chuan; Chen, Tie-Hong

    2012-03-01

    Hydrothermally stable mesoporous aluminosilicates Al-SBA-1 with hierarchical pore structure have been successfully synthesized under alkaline condition at 120 °C by employing organic mesomorphous complexes of polyelectrolyte (poly(acrylic acid) (PAA)) and cationic surfactant (hexadecyl pyridinium chloride (CPC)) as template. The Si/Al ratio could be as high as 5 and the incorporation of Al into the silica framework did not disturb the well-ordered cubic Pm3&cmb.macr;n mesostructure. Meanwhile, the incorporation of Al could greatly increase the specific surface area and pore volume of the samples. The Al-SBA-1 materials exhibited a high hydrothermal stability and remained stable even after being treated in boiling water for 10 days. The catalytic activity of the Al-SBA-1 materials was investigated by employing the Friedel-Crafts alkylation of toluene with benzyl alcohol as a model reaction and they exhibited excellent catalytic property due to the incorporated acid sites and the hierarchically mesoporous structure.

  6. Sodium dodecyl benzene sulfonate-assisted synthesis through a hydrothermal reaction

    Energy Technology Data Exchange (ETDEWEB)

    Sobhani, Azam [Department of Inorganic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, P.O. Box 87317–51167, Islamic Republic of Iran (Iran, Islamic Republic of); Salavati-Niasari, Masoud, E-mail: salavati@kashanu.ac.ir [Department of Inorganic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, P.O. Box 87317–51167, Islamic Republic of Iran (Iran, Islamic Republic of); Institute of Nano Science and Nano Technology, University of Kashan, Kashan, P.O. Box 87317–51167, Islamic Republic of Iran (Iran, Islamic Republic of)

    2012-08-15

    Graphical abstract: Reaction of a SeCl{sub 4} aqueous solution with a NiCl{sub 2}·6H{sub 2}O aqueous solution in presence of sodium dodecyl benzene sulfonate (SDBS) as capping agent and hydrazine (N{sub 2}H{sub 4}·H{sub 2}O) as reductant, produces nanosized nickel selenide through a hydrothermal method. The effect of temperature, reaction time and amounts of reductant on the morphology, particle sizes of NiSe nanostructures has been investigated. Highlights: ► NiSe nanostructures were synthesized by hydrothermal method. ► A novel Se source was used to synthesize NiSe. ► SDBS as capping agent plays a crucial role on the morphology of products. ► A mixture of Ni{sub 3}Se{sub 2} and NiSe was prepared in the presence of 2 ml hydrazine. ► A pure phase of NiSe was prepared in the presence of 4 or 6 ml hydrazine. -- Abstract: The effects of the anionic surfactant on the morphology, size and crystallization of NiSe precipitated from NiCl{sub 2}·6H{sub 2}O and SeCl{sub 4} in presence of hydrazine (N{sub 2}H{sub 4}·H{sub 2}O) as reductant were investigated. The products have been successfully synthesized in presence of sodium dodecyl benzene sulfonate (SDBS) as surfactant via an improved hydrothermal route. A variety of synthesis parameters, such as reaction time and temperature, capping agent and amount of reducing agent have a significant effect on the particle size, phase purity and morphology of the obtained products. The sample size became bigger with decreasing reaction temperature and increasing reaction time. In the presence of 2 ml hydrazine, the samples were found to be the mixture of Ni{sub 3}Se{sub 2} and NiSe. With increasing the reaction time and amount of hydrazine a pure phase of hexagonal NiSe was obtained. X-ray diffraction analysis (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM) images indicate phase, particle size and morphology of the products. Chemical composition and purity of the products were

  7. Hydrothermal Synthesis,Crystal Structure and Magnetic Property of a New Co(Ⅱ) Complex:[Co(4,4'-bpy)_2(H_2O)_2(4-FBA)_2]·(4,4'-bpy)%Hydrothermal Synthesis,Crystal Structure and Magnetic Property of a New Co(Ⅱ) Complex:[Co(4,4'-bpy)_2(H_2O)_2(4-FBA)_2]·(4,4'-bpy)

    Institute of Scientific and Technical Information of China (English)

    ZHANG Bi-Song; ZHENG Miao; WU Chang-Sheng; LI Yun-Xia; QIU Jian-Ping; ZHENG Yue-Qing

    2012-01-01

    A new complex [Co(4,4'-bpy)2(H2O)2(4-FBA)2]·(4,4'-bpy)(1) has been hydro-thermally synthesized using cobalt,4,4'-bipyridyl(4,4'-bpy) and 4-fluorobenzoic acid(4-HFBA),and characterized by thermal analysis,single-crystal X-ray diffraction and magnetic property.The complex crystallizes in the triclinic system,space group P,Z = 1.Crystal data:C54H44CoF2N8O6,Mr = 997.90,a = 9.134(2),b = 11.555(2),c = 12.867(3) ,α = 66.02(3),β = 77.96(3),= 73.11(3)°,V = 1180.9(4) 3,Dc = 1.403 g/cm3,μ(MoKα) = 0.433 mm-1,F(000) = 517,the final R = 0.0633 and wR = 0.1171 for 2152 observed reflections(I 〉 2σ(I)).The title complex is assembled into 1D supramolecular chains parallel to [001] based on the adjacent molecular ··· stacking interactions and hydrogen bonds.The variable temperature magnetic measurements show a weak ferromagnetic behavior over 300-160 K followed by antiferromagnetic behavior below 160 K for the title complex.

  8. SYNTHESIS OF ZEOLITE SOCONY MOBIL FROM BLUE SILICA GEL AND RICE HUSK ASH AS CATALYSTS FOR HYDROTHERMAL LIQUEFACTION

    OpenAIRE

    SUYITNO; SANURYA PUTRI PURBANINGRUM; DOMINICUS DANARDONO; ALFAITORY EMHEMED SALEM; FATHI A. MANSUR

    2015-01-01

    Renewable biofuels produced by the hydrothermal liquefaction of rice husks have received much attention because of rapid increases in fuel consumption and corresponding declines in fossil fuel resources. To increase biofuel yields, template-free syntheses of Zeolite Socony Mobil (ZSM) catalysts based on blue silica gel and rice husk ash as silica sources were studied. After ZSM synthesis in a closed reactor at 170°C, the crystallinity and crystalline diameters of the products were determined ...

  9. Effect of ferrous/ferric ions molar ratio on reaction mechanism for hydrothermal synthesis of magnetite nanoparticles

    Indian Academy of Sciences (India)

    N Mizutani; T Iwasaki; S Watano; T Yanagida; H Tanaka; T Kawai

    2008-10-01

    Magnetite nanoparticles were prepared by hydrothermal synthesis under various initial ferrous/ferric molar ratios without adding any oxidizing and reducing agents in order to clarify effects of the molar ratio on the reaction mechanism for the formation of magnetite nanoparticles. The magnetite nanoparticles prepared were characterized by a scanning electron microscope, powder X-ray diffractometer, and superconducting quantum interference device (SQUID). At the molar ratio corresponding to the stoichiometric ratio in the synthesis reaction of magnetite from ferrous hydroxide and goethite, the nucleation of magnetite crystals progressed rapidly in an initial stage of the hydrothermal synthesis, resulting in formation of the magnetite nanoparticles having a smaller size and a lower crystallinity. On the other hand, at higher molar ratios, the particle size and crystallinity increased with increasing molar ratio because using surplus ferrous hydroxide the crystallites of magnetite nanoparticles grew up slowly under hydrothermal conditions according to the Schikorr reaction. The magnetite nanoparticles prepared under various molar ratios had good magnetic properties regardless of the molar ratio.

  10. Structural synthesis of parallel robots

    CERN Document Server

    Gogu, Grigore

    This book represents the fifth part of a larger work dedicated to the structural synthesis of parallel robots. The originality of this work resides in the fact that it combines new formulae for mobility, connectivity, redundancy and overconstraints with evolutionary morphology in a unified structural synthesis approach that yields interesting and innovative solutions for parallel robotic manipulators.  This is the first book on robotics that presents solutions for coupled, decoupled, uncoupled, fully-isotropic and maximally regular robotic manipulators with Schönflies motions systematically generated by using the structural synthesis approach proposed in Part 1.  Overconstrained non-redundant/overactuated/redundantly actuated solutions with simple/complex limbs are proposed. Many solutions are presented here for the first time in the literature. The author had to make a difficult and challenging choice between protecting these solutions through patents and releasing them directly into the public domain. T...

  11. Microwave-hydrothermal method for the synthesis of composite materials for removal of arsenic from water.

    Science.gov (United States)

    Andjelkovic, Ivan; Jovic, Bojan; Jovic, Milica; Markovic, Marijana; Stankovic, Dalibor; Manojlovic, Dragan; Roglic, Goran

    2016-01-01

    Composite material Zr-doped TiO2, suitable for the removal of arsenic from water, was synthetized with fast and simple microwave-hydrothermal method. Obtained material, Zr-TiO2, had uniform size and composition with zirconium ions incorporated into crystal structure of titanium dioxide. Synthetized composite material had large specific surface area and well-developed micropore and mesopore structure that was responsible for fast adsorption of As(III) and As(V) from water. The influence of pH on the adsorption capacity of arsenic was studied. The kinetics and isotherm experiments were also performed. The treatment of natural water sample containing high concentration of arsenic with composite material Zr-TiO2 was efficient. The concentration of arsenic was reduced to the value recommended by WHO.

  12. Hydrothermal synthesis, characterization and luminescent properties of lanthanide-doped NaLaF$_4$ nanoparticles

    Indian Academy of Sciences (India)

    JIGMET LADOL; HEENA KHAJURIA; SONIKA KHAJURIA; HAQ NAWAZ SHEIKH

    2016-08-01

    Nanoparticles of sodium lanthanum (III) fluoride-doped and co-doped with Eu$^{3+}/Tb$^{3+}$ were prepared by the hydrothermal method using citric acid as structure-directing agent. Structural aspects and optical properties of synthesized nanoparticles were studied by powder X-ray diffraction (XRPD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy-dispersive X-ray spectra (EDS), particle size by dynamic light scattering (DLS), Fourier transform infrared (FTIR) spectrum and photoluminescence (PL) techniques. Nanoparticles consist of well-crystallized hexagonal phase and the average crystallite size for undoped and doped-NaLaF$_4$ nanoparticles are in the range of 20–22 nm. TEM images show that nanoparticles have cylindrical shape and crystalline nature of nanoparticles was confirmed by SAED patterns. Downconversion(DC) luminescent properties of doped NaLaF4 were also investigated and impact of co-doping has been explored.

  13. Hydrothermal Synthesis and Dielectric Characterization of a Double Perovskite Ba2FeSbO6

    Institute of Scientific and Technical Information of China (English)

    LI Min; YUAN Hong-ming; XU Wei; HAN Mei; YAO Lin-ran; YANG Ming; FENG Shou-hua

    2012-01-01

    A double perovskite oxide Ba2FeSbO6 was hydrothermally synthesized and structurally characterized by X-ray diffraction.This solid compound shows a single phase and has a trigonal structure with space group R-3m and cell parameters of a=0.57261 nm and c=1.40244 nm.The dielectric constant and loss tangent of the solid measured in a frequency range from 100 Hz to 1 MHz at temperatures from 313 K to 513 K reveal a relaxation process of frequency dependence of the real part(ε') of dielectric constant and dielectric loss tanδ.The frequency dependence of electrical property led to the framework of conductivity and electric modulus formalisms.The scaling behavior of imaginary part of electric modulus suggests that the relaxation describes the single mechanism at various temperatures.The variation tendency of the alternating current impedance indicates the thermally activated conduction process follows Jonsche's power law.

  14. Synthesis and Characterization of Aluminum Doped Zinc Oxide Nanostructures via Hydrothermal Route

    Directory of Open Access Journals (Sweden)

    A. Alkahlout

    2014-01-01

    Full Text Available Stable crystalline aluminum doped zinc oxide (AZO nanopowders were synthesized using hydrothermal treatment processing. Three different aluminum precursors have been used. The Al-precursors were found to affect the morphology of the obtained nanopowders. AZO nanoparticles based on zinc acetate and aluminum nitrate have been prepared with different Al/Zn molar ratios. XRD investigations revealed that all the obtained powders have single phase zincite structure with purity of about 99%. The effect of aluminum doping ratio in AZO nanoparticles (based on Al-nitrate precursor on structure, phase composition, and particle size has been investigated. The incorporation of Al in ZnO was confirmed by UV-Vis spectroscopy revealing a blue shift due to Burstein-Moss effect.

  15. Investigation of the Optimal Parameters in Hydrothermal Method for the Synthesis of ZnO Nanorods

    Directory of Open Access Journals (Sweden)

    Ying-Chung Chen

    2014-01-01

    Full Text Available We investigated a two-step method to deposit the ZnO-based nanostructure films, including nanorods and nanoflowers. In the first step, sputtering method was used to deposit the ZnO films on SiO2/Si substrates as the seed layer. In the second step, Zn(NO32–6H2O and C6H12N4 were used as precursors and hydrothermal process was used as the method to synthesize the ZnO films. After that, the ZnO films were measured by an X-ray diffraction pattern and a FESEM to analyze their crystallization and morphology. We had found that the ZnO films had three different morphologies synthesized on ZnO/SiO2/Si substrates, including irregular-plate structure films, nanorod films, and beautiful chrysanthemum-like clusters (nanoflower films. We would prove that the face direction of ZnO/SiO2/Si substrates in the hydrothermal bottle and deposition time were two important factors to influence the synthesized results of the ZnO films.

  16. Low temperature synthesis of monodispersed YAG:Eu crystallites by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Mengmeng [Shanghai Institute of Ceramics, Chinese Academy of Sciences, No. 1295 Dingxi Road, Shanghai, 200050 (China); University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing, 100049 (China); Zhang, Zhijun, E-mail: zhangzhijun@shu.edu.cn [School of Materials Science and Engineering, Shanghai University, No. 99 Shangda Road, Shanghai, 200072 (China); Zhao, Jingtai, E-mail: jtzhao@shu.edu.cn [School of Materials Science and Engineering, Shanghai University, No. 99 Shangda Road, Shanghai, 200072 (China); Zhang, Jiazhi [Shanghai Institute of Ceramics, Chinese Academy of Sciences, No. 1295 Dingxi Road, Shanghai, 200050 (China); University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing, 100049 (China); Liu, Zhiwei [Shanghai Institute of Ceramics, Chinese Academy of Sciences, No. 1295 Dingxi Road, Shanghai, 200050 (China)

    2015-10-25

    Single phase europium doped yttrium aluminum garnet (YAG:Eu) crystallites with good dispersity were successfully synthesized by a facile hydrothermal method at 300 °C for 24 h. The influences of the molar ratio of (Y + Eu) to Al (denoted by Ln/Al) in the raw material on the phase, morphology, crystallinity, local environment of Eu ions and photoluminescence properties were investigated. It was found that the monodispersed single phase YAG:Eu crystallites with terminating faces of {110} can be obtained when Ln/Al is 3:4. Eu ions in all the samples are trivalent regardless of Ln/Al, while the local environment of Eu ions is more symmetric when Ln/Al is 3:4. Moreover, the YAG:Eu crystallites obtained when Ln/Al is 3:4 exhibit improved crystallinity, which contributes to the enhanced luminescence intensity. - Highlights: • Single phase YAG:Eu was synthesized by the hydrothermal method at 300 °C. • The YAG:Eu crystallites are monodispersed and exhibit improved crystallinity. • The YAG:Eu crystallites exhibit improved luminescence intensity. • XAFS and VUV were used to investigate the local structure of Eu.

  17. Structural and optical investigations on seed layer assisted hydrothermally grown ZnO nanorods on flat and textured substrates

    Science.gov (United States)

    Rayerfrancis, Arokiyadoss; Balaji Bhargav, P.; Ahmed, Nafis; Balaji, C.; Dhara, Sandip

    2016-12-01

    In this article we report the synthesis of vertically aligned ZnO nanorods on plain as well as textured fluorine doped tin oxide (FTO) coated glass substrate using hydrothermal method. Prior to hydrothermal method, AZO seed layer of thickness 5, 10 and 15 nm were deposited on the chosen substrates by DC magnetron sputtering. The as-grown nanorods were annealed at 450 °C for 3 h to improve the crystallinity. Morphology and structure of the nanorods was observed by field emission scanning electron microscopy. The formation of wurtzite structure was confirmed through x-ray diffraction studies. The optical mode of ZnO, E2 (high) at 434 cm-1 present in the samples was confirmed by Raman spectroscopy. The seed layer assisted growth of ZnO nanorods were defect free, which is confirmed from the photoluminescence spectra, and the intensity of band to band emission is much greater than the emission from the defects at the deep level.

  18. Platelet-like hexagonal SrFe12O19 particles: Hydrothermal synthesis and their orientation in a magnetic field

    Science.gov (United States)

    Zhang, Tao; Peng, Xiaoling; Li, Jing; Yang, Yanting; Xu, Jingcai; Wang, Panfeng; Jin, Dingfeng; Jin, Hongxiao; Hong, Bo; Wang, Xinqing; Ge, Hongliang

    2016-08-01

    Platelet-like hexagonal SrFe12O19 particles were prepared by hydrothermal synthesis, and the effects of molar ratio of Fe/Sr (RFe/Sr) on the phase compositions, morphologies and magnetic properties of as-prepared samples were investigated. The optimum RFe/Sr is identified as 8:1. The hexagonal platelet-like particles are nano-scale in thickness and micro-scale in diameter. The low coercivity is a consequence of the large shape anisotropy of the as-synthesized particles. The platelet-like hexagonal SrFe12O19 particles were then dispersed in epoxy resin and formed ordered arrangement structure which took root in the curing epoxy matrix under an external magnetic field of 8000 Oe. The microstructures, morphologies and magnetic properties of the bulk samples orientated and nonaligned were studied. The platelet-like particles arrange with the platelet perpendicular to the magnetic field direction in the orientated samples. This demonstrates that the easy axis of the particle is perpendicular to the platelet, and that the magnetocrystalline anisotropy still plays a leading role in the changing effective anisotropy with the rapidly growing shape anisotropy. The remanence (Mr) of the bulk samples is changed obviously after orientation, while the coercivity nearly remains constant. That is, the maximum energy products (BH)max can be effectively adjusted by given a suitable magnetic field.

  19. A simple hydrothermal method for the large-scale synthesis of single-crystal potassium tungsten bronze nanowires.

    Science.gov (United States)

    Gu, Zhanjun; Ma, Ying; Zhai, Tianyou; Gao, Bifen; Yang, Wensheng; Yao, Jiannian

    2006-10-10

    The large-scale synthesis of single-crystal K(x)WO(3) tungsten bronze nanowires has been successfully realized by a hydrothermal method under mild conditions. Uniform K(0.33)WO(3) nanowires with diameters of 5-25 nm and lengths of up to several micrometers are obtained. It is found that the morphology and crystallographic forms of the final products are strongly dependent on the sulfate and citric acid, which may act as structure-directing and soft-reducing agent, respectively. Some other influential factors on the growth of tungsten bronze nanowires, such as temperature and reaction time, are also discussed. It is worth noting that other alkali metal tungsten bronzes such as (NH(4))(x)WO(3), Rb(x)WO(3), and Cs(x)WO(3) could also be selectively synthesized by a similar route. Thus, this novel and efficient method could provide a potential mild route to selectively synthesize various tungsten bronze on-dimensional nanomaterials.

  20. Synthesis and Characterization of Si Oxide Coated Nano Ceria by Hydrolysis, and Hydrothermal Treatment at Low Temperature

    Directory of Open Access Journals (Sweden)

    Kong M.

    2017-06-01

    Full Text Available The purpose of this work was to the application of Si oxide coatings. This study deals with the preparation of ceria (CeO2 nanoparticles coating with SiO2 by water glass and hydrolysis reaction. First, the low temperature hydro-reactions were carried out at 30~100°C. Second, Silicon oxide-coated Nano compounds were obtained by the catalyzing synthesis. CeO2 Nano-powders have been successfully synthesized by means of the hydrothermal method, in a low temperature range of 100~200°C. In order to investigate the structure and morphology of the Nano-powders, scanning electron microscopy (SEM and X-ray diffraction (XRD were employed. The XRD results revealed the amorphous nature of silica nanoparticles. To analyze the quantity and properties of the compounds coated with Si oxide, transmission electron microscopy (TEM in conjunction with electron dispersive spectroscopy was used. Finally, it is suggested that the simple growth process is more favorable mechanism than the solution/aggregation process.

  1. Mild oxide-hydrothermal synthesis of different aspect ratios of monoclinic BiVO{sub 4} nanorods tuned by temperature

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Fengqiang; Wu, Qingsheng; Ma, Jie; Chen, Yijun [Department of Chemistry, Tongji University, Shanghai (China)

    2009-01-15

    The monoclinic scheelite BiVO{sub 4} nanocrystals were easily prepared via an oxide-hydrothermal synthesis (OHS) method directly utilizing bulk-phase materials of V{sub 2}O{sub 5} and Bi{sub 2}O{sub 3} as precursor. In the presence of PEG 4000, the reactions were performed in the mild temperature range from 130 C to 200 C. The products were characterized with FTIR, XRD, TEM and UV-vis DRS. These data clearly demonstrated that monoclinic scheelite structure BiVO{sub 4} could be synthesized by the feasible OHS route. The aspect ratios of nanorods were increased with the synthesized temperature. The as-prepared BiVO{sub 4} showed high photocatalytic activity, which was demonstrated by degradation of methylene blue (MB) solution under visible-light irradiation ({lambda}>420 nm). A growth mechanism of bismuth vanadate was proposed. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. One-step synthesis of mesoporous silica–graphene composites by simultaneous hydrothermal coupling and reduction of graphene oxide

    Indian Academy of Sciences (India)

    Juliet Q Dalagan; Erwin P Enriquez

    2014-05-01

    Silica–graphene oxide composites were synthesized by hydrothermal method with simultaneous functionalization and reduction of graphene oxide (GO) in the presence of mesoporous silica. Two types of silica were used in the study, mesoporous synthetic silica (MSU-F) synthesized by sol-gel method and mesoporous mineral silica (meso-celite) from pseudomorphic synthesis. The infrared spectra of the composites showed the disappearance of the carboxyl peak at 1735 cm-1 which could be due to the reduction of the –COOH group. The enhancement of the band at 1385 cm-1 is attributed to the vibration of the Si–O–C=O moiety formed by reaction of the –COOH group of GO and the silanol (Si–OH) of silica. The Raman spectra of the composites show a diminished intensity ratio of D to G band indicating that GO was reduced to graphene sheets. The TEM images demonstrate the coupling of silica to GO surface revealing dense loading of silica on GO in planar structure.

  3. Hydrothermal synthesis of calcium sulfate whisker from flue gas desulfurization gypsum

    Institute of Scientific and Technical Information of China (English)

    Chengjun Liu; Qing Zhao; Yeguang Wang; Peiyang Shi; Maofa Jiang

    2016-01-01

    Plenty of flue gas desulfurization (FGD) gypsum generated from coal-fired power plants for sulfur dioxide se-questration caused many environmental issues. Preparing calcium sulfate whisker (CSW) from FGD gypsum by hydrothermal synthesis is considered to be a promising approach to solve this troublesome problem and uti-lize calcium sulfate in a high-value-added way. The effects of particle size of FGD gypsum, slurry concentration, and additives on CSW were investigated in this work. The results indicated that fine particle size of FGD gypsum and moderately high slurry concentration were beneficial for crystal nucleation and growth. Three additives of magnesium chloride, citric acid, and sodium dodecyl benzene sulfonate (SDBS) were employed in this study. It was found that mean length and aspect ratio of CSW were both decreased by the usage of magnesium chloride, while a small quantity of citric acid or SDBS could improve the CSW morphology. When multi-additives of citric acid-SDBS were employed, the mean length and aspect ratio increased more than 20%. Moreover, surface morphology of CSW went better, and the particle size and crystal shape became more uniform.

  4. Hydrothermal synthesis spherical TiO2 and its photo-degradation property on salicylic acid

    Science.gov (United States)

    Guo, Wenlu; Liu, Xiaolin; Huo, Pengwei; Gao, Xun; Wu, Di; Lu, Ziyang; Yan, Yongsheng

    2012-07-01

    Anatase TiO2 spheres have been prepared using hydrothermal synthesis. The prepared spheres were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and UV-vis diffuse reflectance spectra (UV-vis DRS). The TiO2 consisted of well-defined spheres with size of 3-5 μm. The photocatalytic activity of spherical TiO2 was determined by degradation of salicylic acid under visible light irradiation. It was revealed that the degradation rate of the spherical TiO2 which was processed at 150 °C for 48 h could reach 81.758%. And the kinetics of photocatalytic degradation obeyed first-order kinetic, which the rate constant value was 0.01716 S-1 of the salicylic acid onto TiO2 (temperature: 150, time: 48 h). The kinetics of adsorption followed the pseudo-second-order model and the rate constant was 1.2695 g mg-1 of the salicylic acid onto TiO2 (temperature: 150, time: 48 h).

  5. Hydrothermal Synthesis of Co-Ru Alloy Particle Catalysts for Hydrogen Generation from Sodium Borohydride

    Directory of Open Access Journals (Sweden)

    Marija Kurtinaitienė

    2013-01-01

    Full Text Available We report the synthesis of μm and sub-μm-sized Co, Ru, and Co-Ru alloy species by hydrothermal approach in the aqueous alkaline solutions (pH ≥ 13 containing CoCl2 and/or RuCl3, sodium citrate, and hydrazine hydrate and a study of their catalytic properties for hydrogen generation by hydrolysis of sodium borohydride solution. This way provides a simple platform for fabrication of the ball-shaped Co-Ru alloy catalysts containing up to 12 wt% Ru. Note that bimetallic Co-Ru alloy bowls containing even 7 at.% Ru have demonstrated catalytic properties that are comparable with the ones of pure Ru particles fabricated by the same method. This result is of great importance in view of the preparation of cost-efficient catalysts for hydrogen generation from borohydrides. The morphology and composition of fabricated catalyst particles have been characterized using scanning electron microscopy, energy dispersive X-ray diffraction, and inductively coupled plasma optical emission spectrometry.

  6. Supercritical hydrothermal synthesis of polycrystalline gadolinium aluminum perovskite materials (GdAlO3, GAP

    Directory of Open Access Journals (Sweden)

    HN Girish

    2017-04-01

    Full Text Available The orthorhombic perovskite, Gadolinium aluminum oxide (GdAlO3, GAP material was successfully prepared by hydrothermal supercritical fluid method using co-precipitated gel of GAP. All experiments were carried out in the pressure and temperature ranges of 100–150 MPa and 180–650 °C respectively. The as-prepared GAP samples were systematically characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM, Fourier transform infrared spectroscopy (FT-IR, X-ray spectroscopy (EDS, thermo gravimetry (TGA and differential thermo gravimetry analysis (DTA. The XRD profile confirms fully crystalline and orthorhombic nature of as-prepared materials, which is well correlated to the reported results. The SEM studies reveal that the GAP materials synthesized at 650 °C/150 MPa for 92 hrs possesses polycrystalline nature with average particle size in the range of 5–20 µm. The DTA shows a crystallization peak at 361 °C at this temperature the agglomerated GAP gel starts to crystallize into polycrystalline GAP materials. When compared with other methods, like sol-gel and solid-state reactions our crystallization temperature is very much lower and feasible. This work not only demonstrates a simple way to fabricate GAP polycrystalline materials from co-precipitated gels but also shows a possible utilization of same technique for synthesis of other high temperature materials.

  7. Flexible composite via rapid titania coating by microwave-assisted hydrothermal synthesis

    Indian Academy of Sciences (India)

    RICARDO MARQUES E SILVA; ANDERSON THESING; VINICIUS GONÇALVES DEON; ALICE GONÇALVES OSÓRIO; BRUNO DA SILVEIRA NOREMBERG; NATÁLIA HADLER MARINS; MARCELO ORNAGHI ORLANDI; FABIANA VILLELA DA MOTTA; RUBENS MARIBONDO DO NASCIMENTO; NEFTALI LENIN VILLARREAL CARREÑO

    2017-06-01

    The aim of this work was to prepare a flexible nanocomposite from ultra-fine titanium oxide (TiO$_2$) growth on carbon fibre via microwave-assisted hydrothermal synthesis (MHS) and to evaluate its photocatalytic properties. The TiO$_2$ nanoparticles were directly grown on the carbon fibre (CF). Thus, a study comparing the conventional titania coating vs. the MHS were performed. The significant layer interaction as a function of the coating method on the visible and dark dye photodegradation performance was observed. Techniques such as X-ray diffraction, electron microscopy (field-emission scanning electron microscope (FESEM)), Raman spectroscopy, among others were used aiming to characterize the different route samples. This study reports a reproducible and single method to manufacture of nanocomposites through the growth ofTiO$_2$ nanoparticle on CF by MHS that allow controlling the thickness layer. Similar procedure of synthesized nanocomposite could be applied in different chemical compositions to advanced applications, based on the electrochemical nanostructure.

  8. An Evaluation of the Critical Parameters for Abiotic Peptide Synthesis in Submarine Hydrothermal Systems

    Science.gov (United States)

    Cleaves, H. J.; Aubrey, A. D.; Bada, J. L.

    2009-04-01

    It has been proposed that oligopeptides may be formed in submarine hydrothermal systems (SHSs). Oligopeptides have been synthesized previously under simulated SHS conditions which are likely geochemically implausible. We have herein investigated the oligomerization of glycine under SHS-like conditions with respect to the limitations imposed by starting amino acid concentration, heating time, and temperature. When 10-1 M glycine solutions were heated at 250°C for diketopiperazine (DKP) were detectable. At 200°C, less oligomerization was noted. Peptides beyond glycylglycine (gly2) and DKP were not detected below 150°C. At 10-2 M initial glycine concentration and below, only gly2, DKP, and gly3 were detected, and then only above 200°C at < 20 min reaction time. Gly3 was undetectable at longer reaction times. The major parameters limiting peptide synthesis in SHSs appear to be concentration, time, and temperature. Given the expected low concentrations of amino acids, the long residence times and range of temperatures in SHSs, it is unlikely that SHS environments were robust sources of even simple peptides. Possible unexplored solutions to the problems presented here are also discussed.

  9. Hydrothermal synthesis and characteristic photoluminescence of Er-doped SnO2 nanoparticles

    Science.gov (United States)

    Tuan, Pham Van; Hieu, Le Trung; Nga, La Quynh; Dung, Nguyen Duc; Ha, Ngo Ngoc; Khiem, Tran Ngoc

    2016-11-01

    We report the characteristic photoluminescence (PL) spectra of erbium ion (Er3+)-doped tin dioxide (SnO2)nanoparticles. The materials were prepared via hydrothermal method at 180 °C with in 20 h by using various Er3+ ion concentrations ranging from 0.0 to 1.0 at%. After the synthesis, the materials were characterized through X-ray diffraction and high-resolution transmission electron microscopy. Crystallite SnO2 and its average particle diameter of approximately 5 nm did not change with Er3+ ion dopant concentration. Photoluminescence spectra showed the characteristic light emission from the Er3+ ions. The PL excitation spectra referred to an efficient energy transfer to Er3+ ions in the presence of SnO2nanoparticles. The most intense Er-related emission of SnO2:Er3+ nanoparticles in near infrared region was found in samples containing an Er3+ ion concentration of 0.25 at%. Although the absorption bandgaps of the materials were identified at approximately 3.8 eV, we found that efficient excitation comes with low excitation energy band edge. Excitation is possibly involved in shallow defects in SnO2 nanoparticles.

  10. Synthesis of Hydrotalcite by Hydrothermal Method%镁铝型水滑石水热合成

    Institute of Scientific and Technical Information of China (English)

    谢晖; 矫庆泽; 段雪

    2001-01-01

    The double-layered hydroxide with hydrotalcite structure wasprepared by a hydrothermal method from two mixtures:MgSO4.7H2O with Al2(SO4)3.18H2O and NaOH with Na2CO3. It is found that increasing the ageing temperature and ageing time of the hydrothermal process was favorable for the formation of hydrotalcite structure, and the crystal size of the products could be controlled by varying ageing temperature and time.

  11. Detonation-synthesis nanodiamonds: synthesis, structure, properties and applications

    Energy Technology Data Exchange (ETDEWEB)

    Dolmatov, Valerii Yu [Federal State Unitary Enterprise Special Design-Technology Bureau (FSUE SDTB) ' ' Tekhnolog' ' at the St Petersburg State Institute of Technology (Technical University) (Russian Federation)

    2007-04-30

    The review outlines the theoretical foundations and industrial implementations of modern detonation synthesis of nanodiamonds and chemical purification of the nanodiamonds thus obtained. The structure, key properties and promising fields of application of detonation-synthesis nanodiamonds are considered.

  12. Hydrothermal synthesis, characterization, and thermal properties of alumino silicate azide sodalite, Na8[AlSiO4]6(N3)2

    Science.gov (United States)

    Borhade, A. V.; Wakchaure, S. G.; Dholi, A. G.; Kshirsagar, T. A.

    2017-07-01

    First time we report the synthesis, structural characterization and thermal behavior of an unusual N3 - containing alumino-silicate sodalite mineral. Azide sodalite, Na8[AlSiO4]6(N3)2 has been synthesized under hydrothermal conditions at 433 K in steel lined Teflon autoclave. The structural and microstructural properties of azide sodalite mineral was characterized by various methods including FT-IR, XRD, SEM, TGA, and MAS NMR. Crystal structure have been refined by Rietveld method in P\\bar 43n space group, indicating that the N3 - sodalite has cubic in lattice. High temperature study was carried out to see the effect of thermal expansion on cell dimension ( a o) of azide sodalite. Thermal behavior of sodalite was also assessed by thermogravimetric method.

  13. Hydrothermal synthesis of TiO2 Nanotubes: Microwave heating versus conventional heating

    CSIR Research Space (South Africa)

    Sikhwivhilu, LM

    2010-01-01

    Full Text Available The influence of the method of synthesis in the properties of the tubular structures derived from TiO2 was investigated using XRD, SEM and BET analysis. The use of microwave irradiation resulted in the formation of TiO2 tubes comprising anatase...

  14. Hydrothermal carbonization: a greener route towards the synthesis of advanced carbon materials

    Directory of Open Access Journals (Sweden)

    M.M. Titirici

    2012-09-01

    Full Text Available This review paper provides an overview of thehydrothermal carbonisation (HTC technology, a“green” and versatile strategy for the synthesis ofadvanced carbon materials suitable for a wide varietyof applications of high impact in the current society.We will focus on the carbon formation mechanism,chemical and structural properties of hydrothermalcarbons, porosity development, nanostructuring,functionalisation and applications.

  15. Hydrothermal synthesis of magnetic mesoporous carbon microspheres from carboxymethylcellulose and nickel acetate

    Science.gov (United States)

    Wu, Qiong; Li, Wei; Tan, Jia; Nan, Xi; Liu, Shouxin

    2015-03-01

    Paramagnetic mesoporous carbon spheres with diameters of 1-3 μm were synthesized through the hydrothermal carbonization of carboxymethylcellulose with nickel acetate, followed by high-temperature carbonization in a N2 atmosphere. Monodisperse Ni particles of average size of 2-5 nm were doped into the carbon matrix, and covered the entrances of pores. Ni particles existed as metallic nickel and nickel oxide with ordered lattice structures. The effect of Ni content on the specific surface area, mesopore percentage, and magnetic and adsorption properties were investigated. The highest vitamin B12 adsorption capacity of 103 mg/g was achieved for the sample prepared using 0.04 g of nickel acetate. The Freundlich and Langmuir isotherm models were used to determine the equilibrium uptakes of vitamin B12. Vitamin B12 was physically adsorbed as a monolayer on the carbon spheres. The carbon spheres were easily separated on account of their magnetism.

  16. Highly Crystalline FeCO3 Microparticle Synthesis by Hydrothermal Decomposition of Fe-EDTA Complex

    Science.gov (United States)

    Chirita, M.; Banica, R.; Ieta, A.; Bucur, A.; Sfiarloaga, P.; Ursu, D. H.; Grozescu, I.

    2010-08-01

    In this article, we present an experimental procedure to synthesize highly crystalline FeCO3 by hydrothermal decomposition of Fe(III)-EDTA complex, starting from Ferric Ammonium Sulfate and Na4EDTA main precursors in urea presence. The structure, morphology and composition of the powders were obtained using X-ray powder diffraction and scanning electron microscopy. The peaks were founded, indicate that the synthesized products autoclaved 22 h at 250 °C are pure FeCO3, which was well proved experimentally from EDAX further investigated. The size with appreciatively 100 μm was evaluated by SEM images. Magnetic characterization confirmed the magnetic characteristics of FeCO3. This procedure allowed the FeCO3 microparticles formation with good and stabile crystallographic characteristics.

  17. Hydrothermal synthesis and infrared emissivity property of flower-like SnO2 particles

    Directory of Open Access Journals (Sweden)

    J. X. Tian

    2014-04-01

    Full Text Available The flower-like SnO2 particles are synthesized through a simple hydrothermal process. The microstructure, morphology and the infrared emissivity property of the as-prepared products are characterized by x-ray diffraction (XRD, scanning electron microscopy (SEM, transmission electron microscope (TEM, and infrared spectroradio meter (ISM respectively. The results show that the as-prepared SnO2 products are all indexed to tetragonal cassiterite phase of SnO2. The different molarity ratios of the OH− concentration to Sn4+ concentration ([OH−]:[Sn4+] and the polyacrylamide (PAM lead to the different morphological structures of SnO2, which indicates that both the [OH−]:[Sn4+] and the PAM play an important role in the morphological evolution respectively. The infrared emissivities of the as-prepared SnO2 products are discussed.

  18. Synthesis of nanostructural ZnO using hydrothermal method for dye-sensitized solar cells

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    ZnO nanocrystals with different morphologies were successful synthesized by a simple hydrothermal method combined with and without hexadecyl trimethyl ammonium bromide(CTAB).The phases and morphologies of the products were measured using X-ray diffraction(XRD),scanning electron microscopy(SEM),and transmission electron microscopy(TEM),respectively.The results indicated that the ZnO nanocrystals with different morphologies were of hexagonal wurtzite structure.ZnO nanorods were obtained without using CTAB,and then the morphology of ZnO changed to ZnO nanoflower and the density of nanoflower became denser with the increase of CTAB concentration.ZnO nanoflower and ZnO nanorod as photoanode were applied to dye-sensitized solar cells(DSSC),respectively.The nanoflower shows a higher dye loading,so DSSC with the use of the ZnO nanoflower possesses a higher conversion efficiency than ZnO nanorod.

  19. FACILE HYDROTHERMAL SYNTHESIS AND GROWTH KINETICS OF FE-BASED MAGNETIC NANOPARTICLES

    Institute of Scientific and Technical Information of China (English)

    C.X. You; J.C. Zhang; Y. Shen; Z.W. Song

    2007-01-01

    The facile hydrothermal method was used to synthesize Fe3O4 nanoparticles with an averagediameter of 11nm. The pure body-centered cubic (bcc)-Fe nanoparticles were prepared by reductionof Fe3O4 nanoparticles powder in H2 atmosphere. The structure, morphology and magnetic propertiesof the products were characterized by X-ray powder diffraction (XRD), transmission electronmicroscopy (TEM), thermogravimetric analysis-differential scanning calorimetry (TGA-DSC) andvibrating sample magnetometer (VSM). The results showed that the as-prepared Fe3O4 nanoparticleshad a relatively homogeneous size. The particle diameters became bigger with the increaseof reaction time. The growth kinetics of the Fe3O4 nanoparticles was also briefly discussed. Theproducts exhibited superparamagnetic properties at room temperature and the specific saturationmagnetization was dependent on the particle sizes.

  20. Hydrothermal synthesis and characterization of fluorine & manganese co-doped PZT based cuboidal shaped powder

    Science.gov (United States)

    Nawaz, H.; Shuaib, M.; Saleem, M.; Rauf, A.; Aleem, A.

    2016-08-01

    Cuboidal shaped PZT powder particles based composition Pb0.89(Ba, Sr)0.11(Zr0.52Ti0.48)O3 co- doped with 1 mol% manganese and 2 mol% fluorine was prepared through hydrothermal route. 200-250nm size cuboidal particles were observed under FE-SEM. XRD technique revealed that the perovskite type ceramic structure has a dominant rhombohedral phase. The resultant powder particles were then spray dried, uniaxially pressed and sintered at different temperatures to achieve maximum theoretical density. 98% density was obtained in the pellets at a sintering temperature of 1190°C with an average grain size of 1-3um. The electrical properties of sintered samples were also measured before and after poling to evaluate the effect of dopants on piezoelectric properties.

  1. Hydrothermal synthesis and dielectric properties of chrysanthemum-like ZnO particles

    Institute of Scientific and Technical Information of China (English)

    Yan Jun-Feng; Zhang Zhi-Yong; You Tian-Gui; Zhao Wu; Yun Jiang-Ni

    2009-01-01

    By orthogonal design theory,technological parameters of chrysanthemum-like ZnO particles prepared in a hydrothermal process are optimized. This paper reports a set of technological parameters for growing chrysanthemumlike ZnO particles on a large scale. It investigates the morphologies and crystalline structures of the as-synthesized three-dimensional ZnO particles with a scanning electron microscope,x-ray diffractometer and transmission electron microscope,and the possible growth mechanism on the three-dimensional ZnO particles. The experimental results indicate that the values of ε'、ε" and tan δe gradually increase in the X band with the improvement of the developmental level of chrysanthemum-like ZnO particles,implying that the electromagnetic wave absorbing property depends on the morphologies of three-dimensional ZnO particles.

  2. Large-scale Hydrothermal Synthesis and Characterization of Size-controlled Lanthanum Hydroxide Nanorods

    Institute of Scientific and Technical Information of China (English)

    YI,Ran; ZHANG,Ning; SHI,Rongrong; LI,Yongbo; QIU Guanzhou; LIU Xiaohe

    2009-01-01

    Uniform lanthanum hydroxide nanorods were successfully synthesized in large quantities through a facile hydrothermal synthetic method, in which soluble lanthanum nitrate was used to supply the lanthanum source and triethylamine (TEA) was used as both alkaline agent and complexing agent. The influences of triethylamine amount, surfactant, reaction temperature and time on the size and shape of lanthanum hydroxide nanorods were investigated in detail. Trivalent rare earth ion doped lanthanum hydroxide nanorods were also obtained in this paper. The phase structures and morphologies of the as-prepared products were investigated in detail by X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED) and high-resolution transmis-sion electron microscopy (HRTEM). The probable formation mechanism was proposed based on the experimental results.

  3. Understanding effect of wall structure on the hydrothermal stability of mesostructured silica SBA-15.

    Science.gov (United States)

    Zhang, Fuqiang; Yan, Yan; Yang, Haifeng; Meng, Yan; Yu, Chengzhong; Tu, Bo; Zhao, Dongyuan

    2005-05-12

    Mesostructured silica SBA-15 materials with different structural parameters, such as pore size, pore volume, and wall thickness, etc., were prepared by varying the postsynthesis hydrothermal treatment temperature and adding inorganic salts. The hydrothermal stabilities of these materials in steam (100% water vapor) were systematically investigated using a variety of techniques including powder X-ray diffraction, transmission electron microscopy, nitrogen sorption, and (29)Si solid-state NMR. The effect of the pore size, microporosity or mesoporosity, and wall thickness on the stability was discussed. The results show that all of the SBA-15 materials have a good hydrothermal stability under steam of 600 degrees C for at least 24 h. N(2) sorption measurements show that the Brumauer-Emmett-Teller surface area of SBA-15 materials is decreased by about 62% after treatment under steam at 600 degrees C for 24 h. The materials with thicker walls and more micropores show relatively better hydrothermal stability in steam of 600 degrees C. Interestingly, we found that the microporosity of the mesostructured silica SBA-15 is a very important factor for the hydrothermal stability. To the materials with more micropores, the recombination of Si-O-Si bonds during the high-temperature steam treatment may not cause direct destruction to the wall structure. As a result, SBA-15 materials with more micropores show better stability in pure steam of 600 degrees C. Nevertheless, these materials are easily destroyed in steam of 800 degrees C for 6 h. Two methods to effectively improve the hydrothermal stability are introduced here: one is a high-temperature treatment, and another is a carbon-propping thermal treatment. Thermal treatment at 900 degrees C can enhance the polymerization degree of Si-O-Si bonds and effectively improve the hydrothermal stability of these SBA-15 materials in 800 degrees C steam for 12 h. But, this approach will cause very serious shrinkage of the mesopores

  4. [Chemical structure of bioethanol lignin by low-temperature alkaline catalytic hydrothermal treatment].

    Science.gov (United States)

    Liu, Xiao-Huan; Zhang, Ming-Ming; Wang, Ji-Fu; Xu, Yu-Zhi; Wang, Chun-Peng; Chu, Fu-Xiang

    2013-11-01

    In order to improve the reaction activity of bioethanol lignin, we investigated the activation of bioethanol lignin by a hydrothermal treatment method. Catalytic hydrothermal treatment of bioethanol lignin was performed at 180 degrees C for 3 h in the presence of alkaline solutions (NaOH, Na2 CO3, KOH and K2 CO3), the change in bioethanol lignin structures was studied comparatively by FTIR, 1H NMR,GPC and elemental analysis. FTIR spectra showed that after alkali hydrothermal treatment, the band at 1 375 cm(-1) attributed to the phenolic hydroxyl groups increased, and the band intensity at 1 116 cm(-1) attributed to the ether bond decreased. On the other hand, the band at 1 597 and 1 511 cm(-1) attributed to aromatic skeletal vibration remained almost unchanged. 1H NMR spectra showed that after alkali hydrothermal treatment, the number of aromatic methoxyl is increased, and based on the increment of the content of phenolic hydroxyl, the catalytic activity can be ranked as follows: KOH > NaOH > K2 CO3 > Na2 CO3. Especially for KOH, the increment of the content of phenolic hydroxyl was 170%, because the ion radius of potassium cation is bigger than sodium cation, so the potassium cations more easily formed cation adducts with lignin. GPC results showed that the molecular weight of alkali hydrothermal treatment lignin decreased and the molecular distribution got wider. Elemental analysis showed that hydrothermal treatment could break the interlinkage between lignin and protein, which can reduce the protein content and increase the purity of lignin, meanwhile, the content of O and H both decreased,while C fell, indicating that the bioethanol lignin had suffered a decarbonylation reaction. This is the most benefit of the lignin as a substitute for phenol.

  5. Hydrothermal Synthesis and Characterization of a Metal-Organic Framework by Thermogravimetric Analysis, Powder X-Ray Diffraction, and Infrared Spectroscopy: An Integrative Inorganic Chemistry Experiment

    Science.gov (United States)

    Crane, Johanna L.; Anderson, Kelly E.; Conway, Samantha G.

    2015-01-01

    This advanced undergraduate laboratory experiment involves the synthesis and characterization of a metal-organic framework with microporous channels that are held intact via hydrogen bonding of the coordinated water molecules. The hydrothermal synthesis of Co[subscript 3](BTC)[subscript 2]·12H[subscript 2]O (BTC = 1,3,5-benzene tricarboxylic acid)…

  6. Hydrothermal Synthesis and Characterization of a Metal-Organic Framework by Thermogravimetric Analysis, Powder X-Ray Diffraction, and Infrared Spectroscopy: An Integrative Inorganic Chemistry Experiment

    Science.gov (United States)

    Crane, Johanna L.; Anderson, Kelly E.; Conway, Samantha G.

    2015-01-01

    This advanced undergraduate laboratory experiment involves the synthesis and characterization of a metal-organic framework with microporous channels that are held intact via hydrogen bonding of the coordinated water molecules. The hydrothermal synthesis of Co[subscript 3](BTC)[subscript 2]·12H[subscript 2]O (BTC = 1,3,5-benzene tricarboxylic acid)…

  7. Microwave-Hydrothermal Synthesis and Characterization of High-Purity Nb Doped BaTiO3 Nanocrystals

    Directory of Open Access Journals (Sweden)

    A. Khanfekr

    2014-01-01

    Full Text Available The synthesis of Nb doped BaTiO3 has been investigated under Microwave-Hydrothermal (MH conditions in the temperature of 150°C for only 2 h using C16H36O4Ti, BaH2O2.8H2O and NbCl5 as Ba, Ti and  Nb sources, respectively.  Typical experiments performed on MH processing have not yet reported for Nb doped BaTiO3.  In the MH process, the formation of high purity nano tetragonal Nb-BaTiO3 was strongly enhanced. New hydrothermal method was used instead of the previous solid state reaction for the BaTiO3±Nb2O3 system. The new method uses high pressure to create nano dimension particles in a lower time and temperature. In case of the phase evolution studies, the XRD pattern measurements and Raman spectroscopy were performed. TEM and FE-SEM images were taken for the detailed analysis of the particle size, surface and morphology.  Synthesis of Nb doped BaTiO3 with the Microwave-hydrothermal provides an advantage of fast crystallization and reduced crystal size when compared to existing methods.

  8. Hydrothermal Synthesis, Crystal Structure and Electrochemical Properties of the Copper(Ⅱ) Complex [Cu4O4(phen)4(ClC6H4COO)2(H2O)2]·(H2O)3

    Institute of Scientific and Technical Information of China (English)

    LI Wei; LI Chang-Hong; YANG Ying-Qun; KUANG Yun-Fei

    2006-01-01

    The title complex of copper(Ⅱ) with m-chlorobenzoic acid, 1,10-phenanthroline (phen) and copper perchlorate has been synthesized and characterized in the solvent mixture of water and methanol. Crystal data for this complex: triclinic, space group P, a = 1.06853(12), b = 1.30740(16), c = 1.49546(17) nm, α = 101.791(2), β = 103.413(2), γ = 105.815(2)o, V = 1.8736(4) nm3, Mr = 904.67, Dc = 1.604 g/cm3, Z = 2, F(000) = 924, μ = 1.34 mm-1, GOOF = 1.049, the final R = 0.0324 and wR = 0.0797. The structure analysis shows that a chair-like structure [Cu4O4] is defined by three quadrilaterals shaped by four copper and four oxygen atoms, and every copper ion is coordinated by three oxygen atoms from three water molecules and two nitrogen atoms from one 1,10-phenanthroline molecule, giving a distorted square-pyramidal coordination geometry. The CV analysis results indicate that the electron transfer in the electrode reaction is quasi-reversible.

  9. Recrystallization of starches by hydrothermal treatment: digestibility, structural, and physicochemical properties.

    Science.gov (United States)

    Trinh, Khanh Son

    2015-12-01

    Gelatinized starches were recrystallized under hydrothermal treatment and their properties were characterized by X-ray diffractometry, solid-state (13)C cross-polarization and magic-angle spinning nuclear magnetic resonance, differential scanning calorimetry, gel-permeation chromatography, high-performance anion-exchange chromatography using pulsed amperomeric detection, high-performance size-exclusion chromatography with attached multiangle laser light scattering and refractive index detectors, and digestibility analysis. Amylopectin molecules of hylon (V, VII) and water yam starch contained long side-chains with high proportion of fb1 and fb2. Under hydrothermal treatment, the double helix proportion and relative crystallinity significantly increased and reached maxima of water yam (48.7 and 28.2 %, respectively). Except water yam starch, X-ray diffraction pattern of all starches exhibited the evidence of type 2 amylose-lipid complex. Besides, under DSC measurement, potato and hylon starches showed the endotherm of amylose-amylose interaction. The hydrothermal treatment caused the recrystallization resulting in the decrease of RDS, especially in case of hylon and water yam starch. HTT water yam contained highest SDS (48.3 %) and HTT hylon VII contained highest RS (44.5 %). The relationship between structure and digestibility was observed, in which, high amylose content and specific structures of amylopectin molecule were necessary for the production of RS and/or SDS of hydrothermally treated starches.

  10. Hydrothermal synthesis of hexagonal and orthorhombic MoO{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Chithambararaj, A. [Nanomaterials Laboratory, Department of Physics, National Institute of Technology, Tiruchirappalli 620 015 (India); Bose, A. Chandra, E-mail: acbose@nitt.edu [Nanomaterials Laboratory, Department of Physics, National Institute of Technology, Tiruchirappalli 620 015 (India)

    2011-08-04

    Molybdenum oxide (MoO{sub 3}) with two different crystal structures (hexagonal and orthorhombic) was successfully synthesized by an effective and environmental friendly hydrothermal method. The phase confirmation and structural properties of the sample was elucidated by X-ray diffraction (XRD) method. The reaction temperature has great impact on the crystal structure, size, shape and chemical composition of the samples. Vibration behavior of chemical bonds was characterized by Fourier transform infrared spectroscopy (FT-IR) and the observed peaks confirm the formation of MoO{sub 3}. Scanning electron microscopy (SEM) observation shows that an increase in reaction temperature, the shape was drastically changed from one dimensional (1D) to two dimensional (2D) layered structures. Energy dispersive X-ray analysis (EDX) reveals that the as-prepared samples are in non-stoichiometric composition and their composition varies with reaction temperature. The thermal study was acquired by thermo gravimetric analysis and it demonstrates the process of dehydration and deammonization, observed below 260 deg. C and phase transformation from hexagonal to highly stable orthorhombic phase at 400-450 deg. C. Additionally, the optical absorption properties were measured using diffuse reflectance spectroscopy (DRS) and the band gap energy, estimated from Kubelka-Munk function (K-M) was found to be in the range of 3.01-3.24 eV.

  11. Hydrothermal synthesis of hexagonal CeO{sub 2} nanosheets and their room temperature ferromagnetism

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Fanming, E-mail: mrmeng@ahu.edu.cn [School of Physics and Materials Science, Anhui University, Hefei 230601 (China); Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024 (China); Zhang, Cheng; Fan, Zhenghua; Gong, Jinfeng; Li, Aixia; Ding, Zongling; Tang, Huaibao; Zhang, Miao; Wu, Guifang [School of Physics and Materials Science, Anhui University, Hefei 230601 (China)

    2015-10-25

    Hexagonal CeO{sub 2} nanosheets of 40–50 nm in thickness and 300–400 nm in side-length have been successfully synthesized via controlling the morphology of CeCO{sub 3}OH precursors by a facile hydrothermal technique using CeCl{sub 3}·7H{sub 2}O as cerium source, ammonium hydrogen carbonate as precipitants, and ethylenediamine as complexant. The reaction time and the amount of CeCl{sub 3}·7H{sub 2}O and ethylenediamine were systematically investigated. The as-synthesized hexagonal CeO{sub 2} nanosheets were examined by XRD, SEM, TEM, XPS, Raman scattering and magnetization measurements. It is found that the amount of CeCl{sub 3}·7H{sub 2}O and ethylenediamine are key parameters for controlling the final morphology. The hexagonal CeO{sub 2} nanosheets have a fluorite cubic structure and there are Ce{sup 3+} ions and oxygen vacancies in surface of samples. The synthesized CeO{sub 2} shows excellent room temperature optical properties. M–H curve exhibits excellent room-temperature ferromagnetism (RTFM) with saturation magnetization (M{sub s}) of 3.02 × 10{sup −2} emu/g, residual magnetization (M{sub r}) of 0.68 × 10{sup −2} emu/g and coercivity (H{sub c}) of 210 Oe, which is likely attributed to the effects of the Ce{sup 3+} ions and oxygen vacancies. - Highlights: • Hexagonal CeO{sub 2} nanosheets with superexerllent RTFM are synthesized by a facile hydrothermal method. • RTFM mechanism of CeO{sub 2} nanosheets can be attributed to the influences of oxygen vacancies and Ce{sup 3+} ions. • A defect driven dissolution–recrystallization mechanism is suggested to explain the transformation from nanowires to nanosheets.

  12. Microwave assisted facile hydrothermal synthesis and characterization of zinc oxide flower grown on graphene oxide sheets for enhanced photodegradation of dyes

    Science.gov (United States)

    Kashinath, L.; Namratha, K.; Byrappa, K.

    2015-12-01

    Microwave assisted hydrothermal process of synthesis of ZnO-GO nanocomposite by using ZnCl2 and NaOH as precursors is being reported first time. In this investigation, a novel route to study on synthesis, interaction, kinetics and mechanism of hybrid zinc oxide-graphene oxide (ZnO-GO) nanocomposite using microwave assisted facile hydrothermal method has been reported. The results shows that the ZnO-GO nanocomposite exhibits an enhancement and acts as stable photo-response degradation performance of Brilliant Yellow under the UV light radiation better than pure GO and ZnO nanoparticles. The microwave exposure played a vital role in the synthesis process, it facilitates with well define crystalline structure, porosity and fine morphology of ZnO/GO nanocomposite. Different molar concentrations of ZnO precursors doped to GO sheets were been synthesized, characterized and their photodegradation performances were investigated. The optical studies by UV-vis and Photo Luminescence shows an increase in band gap of nanocomposite, which added an advantage in photodegradation performance. The in situ flower like ZnO nano particles are were densely decorated and anchored on the surfaces of graphene oxide sheets which aids in the enhancement of the surface area, adsorption, mass transfer of dyes and evolution of oxygen species. The nanocomposite having high surface area and micro/mesoporous in nature. This structure and morphology supports significantly in increasing photo catalytic performance legitimate to the efficient photosensitized electron injection and repressed electron recombination due to electron transfer process with GO as electron collector and transporter dependent on the proportion of GO in ZnO/GO composite.

  13. Hydrothermal synthesis of nanocubes of sillenite type compounds for photovoltaic applications and solar energy conversion of carbon dioxide to fuels

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, Vaidyanathan; Murugesan, Sankaran

    2014-04-29

    The present invention relates to formation of nanocubes of sillenite type compounds, such as bismuth titanate, i.e., Bi.sub.12TiO.sub.20, nanocubes, via a hydrothermal synthesis process, with the resulting compound(s) having multifunctional properties such as being useful in solar energy conversion, environmental remediation, and/or energy storage, for example. In one embodiment, a hydrothermal method is disclosed that transforms nanoparticles of TiO.sub.2 to bismuth titanate, i.e., Bi.sub.12TiO.sub.20, nanocubes, optionally loaded with palladium nanoparticles. The method includes reacting titanium dioxide nanotubes with a bismuth salt in an acidic bath at a temperature sufficient and for a time sufficient to form bismuth titanate crystals, which are subsequently annealed to form bismuth titanate nanocubes. After annealing, the bismuth titanate nanocubes may be optionally loaded with nano-sized metal particles, e.g., nanosized palladium particles.

  14. Hydrothermal Synthesis,Crystal Structure,Spectrum Properties and Quantum Chemical Calculation of a Trinuclear Copper(Ⅱ) Complex with 3-(Pyridin-2-yl)-1,2,4-triazole

    Institute of Scientific and Technical Information of China (English)

    LI Chang-Hong; LI Wei; LI Yu-Lin; YANG Ying-Qun

    2012-01-01

    A three-dimensional framework copper(Ⅱ) coordination polymer with copper carbonate basic and 3-(pyridin-2-yl)-1,2,4-triazole (Hpt) has been hydrothemally synthesized.The complex (2,C14 H10 CuN8 ·3H2 O) crystallizes in tetragonal,space group P4 2 /n,a=2.08581(12),b=2.08581(12),c=0.72331(4) nm,M r=761.73,V=3.1468(3) nm 3,Dc=1.608 g/cm 3,Z=4,F(000)=1552,GOOF=1.07,R=0.0515 and wR=0.1689.Every asymmetric unit molecular structure of the complex is composed with one copper ion,one and half water molecules and two Hpt molecules.Each copper ion is coordinated with five nitrogen atoms from four Hpt molecules,forming a distorted square pyramidal geometry.The fluorescence spectrum analysis shows that the title complex at room temperature exhibits intense photoluminescence with maximum emission at 450 nm.The quantum chemistry calculation study on the complex has been performed.The stability,some frontier molecular orbital energies and composition characteristics of some frontier molecular orbitals of the complex have been investigated.

  15. Tailoring surface and photocatalytic properties of ZnO and nitrogen-doped ZnO nanostructures using microwave-assisted facile hydrothermal synthesis

    Science.gov (United States)

    Rangel, R.; Cedeño, V.; Ramos-Corona, A.; Gutiérrez, R.; Alvarado-Gil, J. J.; Ares, O.; Bartolo-Pérez, P.; Quintana, P.

    2017-08-01

    Microwave hydrothermal synthesis, using an experimental 23 factorial design, was used to produce tunable ZnO nano- and microstructures, and their potential as photocatalysts was explored. Photocatalytic reactions were conducted in a microreactor batch system under UV and visible light irradiation, while monitoring methylene blue degradation, as a model system. The variables considered in the microwave reactor to produce ZnO nano- or microstructures, were time, NaOH concentration and synthesis temperature. It was found that, specific surface area and volume/surface area ratio were affected as a consequence of the synthesis conditions. In the second stage, the samples were plasma treated in a nitrogen atmosphere, with the purpose of introducing nitrogen into the ZnO crystalline structure. The central idea is to induce changes in the material structure as well as in its optical absorption, to make the plasma-treated material useful as photocatalyst in the visible region of the electromagnetic spectrum. Pristine ZnO and nitrogen-doped ZnO compounds were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), specific surface area (BET), XPS, and UV-Vis diffuse reflectance spectroscopy. The results show that the methodology presented in this work is effective in tailoring the specific surface area of the ZnO compounds and incorporation of nitrogen into their structure, factors which in turn, affect its photocatalytic behavior.

  16. Hydrothermal Synthesis and Tunable Multicolor Upconversion Emission of Cubic Phase Y2O3 Nanoparticles

    Directory of Open Access Journals (Sweden)

    Haibo Wang

    2013-01-01

    Full Text Available Highly crystalline body-centered cubic structure Y2O3 with lanthanide (Ln codopants (Ln = Yb3+/Er3+ and Yb3+/Ho3+ has been synthesized via a moderate hydrothermal method in combination with a subsequent calcination. The structure and morphology of Y(OH3 precursors and Y2O3 nanoparticles were characterized by X-ray diffraction and transmission electron microscopy. The results reveal that the Y2O3 nanoparticles possess cubic phase and form the quasispherical structure. The upconversion luminescence properties of Y2O3 nanoparticles doped with different Ln3+ (Yb3+/ Er3+ and Yb3+/ Ho3+ ions were well investigated under the 980 nm excitation. The results show that the Yb3+/Er3+ and Yb3+/Ho3+ codoped Y2O3 nanoparticles exhibit strong red and light yellow upconversion emissions, respectively. It is expected that these Y2O3 nanoparticles with tunable multicolor output and intense red upconversion emission may have potential application in color displays and biolabels.

  17. Hydrothermal synthesis of CdTe QDs: Their luminescence quenching in the presence of bio-molecules and observation of bistable memory effect in CdTe QD/PEDOT:PSS heterostructure

    Energy Technology Data Exchange (ETDEWEB)

    Khatei, Jayakrishna [Department of Physics, Indian Institute of Science, Bangalore 560012 (India); Koteswara Rao, K.S.R., E-mail: ksrkrao@physics.iisc.ernet.in [Department of Physics, Indian Institute of Science, Bangalore 560012 (India)

    2011-10-17

    Highlights: {center_dot} CdTe QD has been prepared by modified hydrothermal method in room ambient. {center_dot} Luminescence quenching of CdTe QDs in the presence of bio-molecules demonstrated. {center_dot} The CdTe QDs shows memory effect (electrical bistability). - Abstract: We report one-pot hydrothermal synthesis of nearly mono-disperse 3-mercaptopropionic acid capped water-soluble cadmium telluride (CdTe) quantum dots (QDs) using an air stable Te source. The optical and electrical characteristics were also studied here. It was shown that the hydrothermal synthesis could be tuned to synthesize nano structures of uniform size close to nanometers. The emissions of the CdTe QDs thus synthesized were in the range of 500-700 nm by varying the duration of synthesis. The full width at half maximum (FWHM) of the emission peaks is relatively narrow (40-90 nm), which indicates a nearly uniform distribution of QD size. The structural and optical properties of the QDs were characterized by transmission electron microscopy (TEM), photoluminescence (PL) and Ultraviolet-visible (UV-Vis) spectroscopy. The photoluminescence quenching of CdTe QDs in the presence of L-cysteine and DNA confirms its biocompatibility and its utility for biosensing applications. The room temperature current-voltage characteristics of QD film on ITO coated glass substrate show an electrically induced switching between states with high and low conductivities. The phenomenon is explained on the basis of charge confinement in quantum dots.

  18. Structure, chemical bonding states, and optical properties of the hetero-structured ZnO/CuO prepared by using the hydrothermal and the electrospinning methods

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Kyong-Soo; Kim, Jong Wook; Bae, Jong-Seong; Hong, Tae Eun; Jeong, Euh Duck; Jin, Jong Sung; Ha, Myoung Gyu; Kim, Jong-Pil, E-mail: jpkim@kbsi.re.kr

    2017-01-01

    ZnO-branched nanostructures have recently attracted considerable attention due to their rich architectures and promising applications in the field of optoelectronics. Contrary to n-type semiconducting metal oxides, cupric oxide is a p-type semiconductor which can be applied to high-critical-temperature superconductors, photovoltaic materials, field emission, and catalysis. We report the synthesis of the ZnO nanorods on the CuO nanofibers prepared by using the electrospinning method along with the hydrothermal method. As the growing time increases, emission spectra of the hetero-structured ZnO/CuO show that the observed band in the UV region is slightly increased, while the intensity of the green emission is highly enhanced. The hetero-structured ZnO/CuO is found to be a promising candidate for developing renewable devices with photoluminescent behavior and the increased surface to volume ratio.

  19. Hydrothermal Synthesis of H3PW12O40/TiO2 Nanometer Photocatalyst and Its Catalytic Performance for Methyl Orange

    Institute of Scientific and Technical Information of China (English)

    FENG Chang-gen; SHANG Hai-ru

    2012-01-01

    H3PW12O40/TiO2 nanometer photocatalyst was prepared by one step hydrothermal synthesis from H3PW12O40′nH2O and Ti(OBu)4,simultaneously realizing the load and modification of H3PW12O40.The catalyst was characterized by Fourier transform infrared spectroscopy(FTIR),powder X-ray diffraction(XRD),nitrogen adsorption-desorption analysis and scanning electron microscopy(SEM).The results show that the catalyst is Keggin structure and crystallized in anatase structure,the diameter and specific area of the prepared catalyst are 3.8 nm and 177.9m2/g,respectively,and its dispersity is better.The photocatalytic properties were compared for TiO2,H3PW12O40/TiO2 prepared by impregnation and H3PW12O40/TiO2 prepared by hydrothermal method with methyl orange as a probe.The effects of H3PW12O40 loadings,crystallization method,initial pH and concentration of dye solution on the degradation of methyl orange were investigated.

  20. Hydrothermal Synthesis of Cparbonate Pillared Mg-Al Hydrotalcite Compound%镁铝水滑石的高温水热合成研究

    Institute of Scientific and Technical Information of China (English)

    王朋仁

    2014-01-01

    采用水热法合成铝镁水滑石,并通过X射线衍射( XRD)、红外光谱( FT-IR)、透射电镜( TEM)、热分析( DSC)、粒度分析等手段对合成的水滑石进行表征,研究高温水热法合成的水滑石结构及热性能。将自制样品和进口样品进行对比测试,研究结论为自制样品和进口样品结构和热性能基本一致。%Samples of Mg/Al hydrotalcite were synthesized by hydrothermal method, and characterized by XRD, FT-IR, TEM, DSC, particle analysis, etc. Effect of high-temperature hydrothermal synthesis on structure and thermal property of hydrotalcite was studied. The research showed that homemade samples and imported samples were basically the same on structure and thermal properties.

  1. Optical and Magnetic Properties of Fe Doped ZnO Nanoparticles Obtained by Hydrothermal Synthesis

    Directory of Open Access Journals (Sweden)

    Xiaojuan Wu

    2014-01-01

    Full Text Available Diluted magnetic semiconductors Zn1-xFexO nanoparticles with different doping concentration (x=0, 0.01, 0.05, 0.10, and 0.20 were successfully synthesized by hydrothermal method. The crystal structure, morphology, and optical and magnetic properties of the samples were characterized by X-ray diffraction (XRD, energy dispersive spectrometer (EDS, high-resolution transmission electron microscopy (HRTEM, Raman scattering spectra (Raman, photoluminescence spectra (PL, and the vibrating sample magnetometer (VSM. The experiment results show that all samples synthesized by this method possess hexagonal wurtzite crystal structure with good crystallization, no other impurity phases are observed, and the morphology of the sample shows the presence of ellipsoidal nanoparticles. All the Fe3+ successfully substituted for the lattice site of Zn2+ and generates single-phase Zn1-xFexO. Raman spectra shows that the peak shifts to higher frequency. PL spectra exhibit a slight blue shift and the UV emission is annihilated with the increase of Fe3+ concentration. Magnetic measurements indicated that Fe-doped ZnO samples exhibit ferromagnetic behavior at room temperature and the saturation magnetization is enhanced with the increase of iron doping content.

  2. Facile hydrothermal synthesis of one-dimensional nanostructured α-MnO2 for supercapacitors

    Science.gov (United States)

    Wei, Hongmei; Wang, Jinxing; Yang, Shengwei; Zhang, Yangyang; Li, Tengfei; Zhao, Shuoqing

    2016-09-01

    α-MnO2 recently becomes a promising candidate of electrode materials for high effective supercapacitors in which it possesses of unique structure of 2×2 tunnels that can provide more electrons and ions diffusion paths. In this work, different morphologies MnO2 with α-phase crystalline structure have been prepared via a one-step facile hydrothermal method by adding various reagents. Compositions, microstructures and morphologies of these as-synthesized materials were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) and electrochemical properties of α-MnO2 electrodes were studied by the cyclic voltammetry (CV), galvanostatic charge/discharge and electrochemical impedance spectroscopy (EIS) in 1 M Na2SO4 aqueous solution. The specific capacitance of nanowires were 158 F g-1 while the specific capacitance of nanorods were 106 F g-1 at current density of 4 A g-1, and improved performance of the wire-like electrode material was probably ascribed to the larger specific surface area that can provide relatively more active sites for high capacity. Meanwhile, both the nanowires and nanorods of MnO2 presented fine cycle stability after continuous multiple charge/discharge times.

  3. Low temperature hydrothermal synthesis of octahedral Fe{sub 3}O{sub 4} microcrystals

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Wei; Gai Ligang; Li Zhili; Jiang Haihui; Ma Wanyong [School of Chemical Engineering, Shandong Institute of Light Industry, Jinan 250353 (China)], E-mail: liganggai@yahoo.com

    2008-11-21

    Octahedral Fe{sub 3}O{sub 4} crystals in the size range of 200-300 nm have been prepared with a high yield at a low temperature of 90 deg. C using a simple polyethylene glycol (PEG)-mediated hydrothermal approach. It is found that both PEG molecules and NaOH content are crucial for the formation of Fe{sub 3}O{sub 4} octahedrons because of the selective adsorption of PEG molecules on the (1 1 1) planes of Fe{sub 3}O{sub 4} at higher NaOH concentrations, delaying the crystal growth along the [1 1 1] axis. The formation mechanisms related to Fe{sub 3}O{sub 4} nuclei, octahedral crystals, and their linear self-assembly structures are discussed. Magnetization measurements show that the Fe{sub 3}O{sub 4} octahedrons have a relatively high magnetic saturation value of 85.5 emu g{sup -1} and a coercive field of 118 Oe, which is ascribed to the high crystalline perfection and chain-like structures of the sample.

  4. Room-temperature synthesis, hydrothermal recrystallization, and properties of metastable stoichiometric FeSe.

    Science.gov (United States)

    Nitsche, F; Goltz, T; Klauss, H-H; Isaeva, A; Müller, U; Schnelle, W; Simon, P; Doert, Th; Ruck, M

    2012-07-01

    Room-temperature precipitation from aqueous solutions yields the hitherto unknown metastable stoichiometric iron selenide (ms-FeSe) with tetragonal anti-PbO type structure. Samples with improved crystallinity are obtained by diffusion-controlled precipitation or hydrothermal recrystallization. The relations of ms-FeSe to superconducting β-FeSe(1-x) and other neighbor phases of the iron-selenium system are established by high-temperature X-ray diffraction, DSC/TG/MS (differential scanning calorimetry/thermogravimetry/mass spectroscopy), (57)Fe Mössbauer spectroscopy, magnetization measurements, and transmission electron microscopy. Above 300 °C, ms-FeSe decomposes irreversibly to β-FeSe(1-x) and Fe(7)Se(8). The structural parameters of ms-FeSe (P4/nmm, a = 377.90(1) pm, c = 551.11(3) pm, Z = 2), obtained by Rietveld refinement, differ significantly from literature data for β-FeSe(1-x). The Mössbauer spectrum rules out interstitial iron atoms or additional phases. Magnetization data suggest canted antiferromagnetism below T(N) = 50 K. Stoichiometric non-superconducting ms-FeSe can be regarded as the true "parent" compound for the "11" iron-chalcogenide superconductors and may serve as starting point for new chemical modifications.

  5. Synthesis and Enhanced Photocatalytic Activity of Ce-Doped Zinc Oxide Nanorods by Hydrothermal Method

    Science.gov (United States)

    Aisah, N.; Gustiono, D.; Fauzia, V.; Sugihartono, I.; Nuryadi, R.

    2017-02-01

    Zinc oxide (ZnO) is a n-type semiconductor material which has a wide direct band gap energy of ∼ 3.3 eV, and other interesting optical properties, hence it’s potentially applied to various fields such as electronics, optoelectronics, sensors, photonic devices, and also photocatalyst. Dopant in ZnO nanostructures is an effective way to improve ZnO’s structural properties in various applications. In this study, undoped and Ce doped ZnO nanorods were synthesized on ITO coated glass substrates by ultrasonic spray pyrolysis for seeding deposition and hydrothermal methods at a temperature of 95 0C for 2 hours for growth. X-ray diffraction, field emission scanning electron microscopy (FESEM), UV-VIS and Photoluminescence spectroscopy were used to characterize the crystal structure, surface morphology and optical properties of ZnO nanorods and the photocatalytic activity test for methylene blue degradation. The experimental results showed that 3% Cerium dopant has produced hexagonal morphology ZnO nanorod growing more uniform on (002) crystal planes, increased the intensity of ultraviolet absorbance thereby increase the degradation speed of methylene blue.

  6. Hydrothermal synthesis of core-shell TiO2 to enhance the photocatalytic hydrogen evolution

    Science.gov (United States)

    Jiang, Jinghui; Zhou, Han; Zhang, Fan; Fan, Tongxiang; Zhang, Di

    2016-04-01

    A hydrothermal approach was designed to synthesize core-shell TiO2 with interior cavity by making sodium dodecyl sulfonate (SDS) as the surfactant and the mixture of water and ethanol as the solvent. The control experiment of solvent reveals ethanol and water are responsible for the formation of sphere and interior cavity, respectively. Besides, SDS can assist the growth of core-shell structure, and the sizes of sphere and interior cavity can be tuned by regulating the reaction time or temperature. UV-vis absorption proves core-shell structure with interior cavity can increase the absorption of incident light to enhance the optical activity of final product. The calculated bandgap and photoluminescence (PL) analyses reveal the coexistence of rutile in final product can optimize the bandgap to 3.03 eV and delay the charge recombination. As a result, an effective photocatalytic hydrogen evolution under full spectrum irradiation can be harvested by the as-synthesized core-shell spheres to reach a quantum yield, approximately 9.57% at 340 nm wavelength.

  7. A Comparative Characterization of the HPA-MCM-48 Type Catalysts Produced by the Direct Hydrothermal and Room Temperature Synthesis Methods

    Directory of Open Access Journals (Sweden)

    Y. Gucbilmez

    2012-01-01

    Full Text Available MCM-48 type support materials synthesized by the direct hydrothermal synthesis (HTS and room temperature synthesis (RTS methods were incorporated with tungstophosphoric acid (TPA in the range of 10–40 wt% by using a wet impregnation technique in methanol solutions. Resulting HPA-MCM-48 catalysts were characterized by the XRD, Nitrogen Physisorption, SEM, TEM, EDS, and FT-IR methods in order to determine the effects of different initial synthesis conditions on the catalyst properties. RTS samples were found to have better crystalline structures, higher BET surface areas, and higher BJH pore volumes than HTS samples. They also had slightly higher TPA incorporation, except for the 40 wt% samples, as evidenced by the EDS results. Keggin ion structure was preserved, for both methods, even at the highest acid loading of 40 wt%. It was concluded that the simpler and more economical RTS method was more successful than the HTS method for heteropoly acid incorporation into MCM-48 type materials.

  8. Resistivity structure and geochemistry of the Jigokudani Valley hydrothermal system, Mt. Tateyama, Japan

    Science.gov (United States)

    Seki, Kaori; Kanda, Wataru; Tanbo, Toshiya; Ohba, Takeshi; Ogawa, Yasuo; Takakura, Shinichi; Nogami, Kenji; Ushioda, Masashi; Suzuki, Atsushi; Saito, Zenshiro; Matsunaga, Yasuo

    2016-10-01

    This study clarifies the hydrothermal system of Jigokudani Valley near Mt. Tateyama volcano in Japan by using a combination of audio-frequency magnetotelluric (AMT) survey and hot-spring water analysis in order to assess the potential of future phreatic eruptions in the area. Repeated phreatic eruptions in the area about 40,000 years ago produced the current valley morphology, which is now an active solfatara field dotted with hot springs and fumaroles indicative of a well-developed hydrothermal system. The three-dimensional (3D) resistivity structure of the hydrothermal system was modeled by using the results of an AMT survey conducted at 25 locations across the valley in 2013-2014. The model suggests the presence of a near-surface highly conductive layer of < 50 m in thickness across the entire valley, which is interpreted as a cap rock layer. Immediately below the cap rock is a relatively resistive body interpreted as a gas reservoir. Field measurements of temperature, pH, and electrical conductivity (EC) were taken at various hot springs across the valley, and 12 samples of hot-spring waters were analyzed for major ion chemistry and H2O isotopic ratios. All hot-spring waters had low pH and could be categorized into three types on the basis of the Cl-/SO 42 - concentration ratio, with all falling largely on a mixing line between magmatic fluids and local meteoric water (LMW). The geochemical analysis suggests that the hydrothermal system includes a two-phase zone of vapor-liquid. A comparison of the resistivity structure and the geochemically inferred structure suggests that a hydrothermal reservoir is present at a depth of approximately 500 m, from which hot-spring water differentiates into the three observed types. The two-phase zone appears to be located immediately beneath the cap rock structure. These findings suggest that the hydrothermal system of Jigokudani Valley exhibits a number of factors that could trigger a future phreatic eruption.

  9. Structural and optical characterization and scintillator application of hydrothermal-grown ZnO microrods

    Science.gov (United States)

    Empizo, Melvin John F.; Santos-Putungan, Alexandra B.; Yamanoi, Kohei; Salazar, Hernanie T.; Anguluan, Eloise P.; Mori, Kazuyuki; Arita, Ren; Minami, Yuki; Luong, Mui Viet; Shimizu, Toshihiko; Estacio, Elmer S.; Somintac, Armando S.; Salvador, Arnel A.; Sarmago, Roland V.; Fukuda, Tsuguo; Sarukura, Nobuhiko

    2017-03-01

    ZnO microrods are fabricated by a simple hydrothermal growth route using zinc acetate dihydrate [Zn(CH3COO)2·2H2O] and hexamethylenetetramine [(CH2)6N4] aqueous solutions. The as-prepared microrods exhibit uniform dimensions, well-faceted surfaces, and hexagonal crystal structure. The microrods also have an intense ultraviolet (UV) emission at 392 nm with an average lifetime of 80 ps. No peaks are observed at the visible wavelengths that can be attributed to defect-related emissions. With excellent structural and optical properties and with loose adhesion to their substrates, the ZnO microrods can be isolated, harvested, and manipulated and can be integrated as building blocks of a microstructured scintillator screen. The proposed scintillator screen possibly offers efficient and precise detection with high resolution. Hydrothermal-grown ZnO microrods then hold a promise towards radiation detector innovation and integrated optoelectronic microsystems.

  10. One-step hydrothermal synthesis and electrochemical performance of sodium-manganese-iron phosphate as cathode material for Li-ion batteries

    Science.gov (United States)

    Karegeya, Claude; Mahmoud, Abdelfattah; Vertruyen, Bénédicte; Hatert, Frédéric; Hermann, Raphaël P.; Cloots, Rudi; Boschini, Frédéric

    2017-09-01

    The sodium-manganese-iron phosphate Na2Mn1.5Fe1.5(PO4)3 (NMFP) with alluaudite structure was obtained by a one-step hydrothermal synthesis route. The physical properties and structure of this material were obtained through XRD and Mössbauer analyses. X-ray diffraction Rietveld refinements confirm a cationic distribution of Na+ and presence of vacancies in A(2)', Na+ and small amounts of Mn2+ in A(1), Mn2+ in M(1), 0.5 Mn2+ and Fe cations (Mn2+,Fe2+ and Fe3+) in M(2), leading to the structural formula Na2Mn(Mn0.5Fe1.5)(PO4)3. The particles morphology was investigated by SEM. Several reactions with different hydrothermal reaction times were attempted to design a suitable synthesis protocol of NMFP compound. The time of reaction was varied from 6 to 48 h at 220 °C. The pure phase of NMFP particles was firstly obtained when the hydrothermal reaction of NMFP precursors mixture was maintained at 220 °C for 6 h. When the reaction time was increased from 6 to 12, 24 and 48 h, the dandelion structure was destroyed in favor of NMFP micro-rods. The combination of NMFP (NMFP-6H, NMFP-12H, NMFP-24H and NMFP-48H) structure refinement and Mössbauer characterizations shows that the increase of the reaction time leads to the progressive increment of Fe(III) and the decrease of the crystal size. The electrochemical tests indicated that NMFP is a 3 V sodium intercalating cathode. The comparison of the discharge capacity evolution of studied NMFP electrode materials at C/5 current density shows different capacities of 48, 40, 34 and 34 mA h g-1 for NMFP-6H, NMFP-12H, NMFP-24H and NMFP-48H respectively. Interestingly, all samples show excellent capacity retention of about 99% during 50 cycles.

  11. MWW-type titanosilicate synthesis, structural modification and catalytic applications to green oxidations

    CERN Document Server

    Wu, Peng; Xu, Le; Liu, Yueming; He, Mingyuan

    2013-01-01

    This book provides a comprehensive review of a new generation of selective oxidation titanosilicate catalysts with the MWW topology (Ti-MWW) based on the research achievements of the past 12 years. It gives an overview of the synthesis, structure modification and catalytic properties of Ti-MWW. Ti-MWW can readily be prepared by means of direct hydrothermal synthesis with crystallization-supporting agents, using dual-structure-directing agents and a dry-gel conversion technique. It also can be post-synthesized through unique reversible structure transformation and liquid-phase isomorphous subst

  12. Surfactant-free hydrothermal synthesis of lithium aluminate microbricks and nanorods from aluminium oxide nanoparticles.

    Science.gov (United States)

    Joshi, Upendra A; Chung, Soo Hyun; Lee, Jae Sung

    2005-09-21

    Beta-LiAlO2 microbricks and rectangular nanorods have been successfully synthesized from Al2O3 nanoparticles by a simple hydrothermal process without any surfactant or template, by simply changing the Li/Al molar ratio.

  13. Structure of the Nemrut caldera (Eastern Anatolia, Turkey) and associated hydrothermal fluid circulation

    Science.gov (United States)

    Ulusoy, İnan; Labazuy, Philippe; Aydar, Erkan; Ersoy, Orkun; Çubukçu, Evren

    2008-07-01

    Plio-Quaternary volcanism played an important role in the present physical state of Eastern Anatolia. Mount Nemrut, situated to the west of Lake Van is one of the main volcanic centers in the region, with a spectacular summit caldera 8.5 × 7 km in diameter. The most recent eruptions of the volcano were in 1441, 1597 and 1692. Nemrut Lake covers the western half of the caldera; it is a deep, half-bowl-shaped lake with a maximum depth of 176 m. Numerous eruption centers are exposed within the caldera as a consequence of magma-water interaction. Current activity of Nemrut caldera is revealed as hot springs, fumaroles and a small, hot lake. Self-potential and bathymetric surveys carried out in the caldera were used to characterize the structure of the caldera and the associated hydrothermal fluid circulation. In addition, analyses based on digital elevation models and satellite imagery were used to improve our knowledge about the structure of the caldera. According to SP results, the flanks of the volcano represent "the hydrogeologic zone", whereas the intra-caldera region is an "active hydrothermal area" where the fluid circulation is controlled by structural discontinuities. There is also a northern fissure zone which exhibits hydrothermal signatures. Nemrut caldera collapsed piecemeal, with three main blocks. Stress controlling the collapse mechanism seems to be highly affected by the regional neotectonic regime. In addition to the historical activity, current hydrothermal and hydrogeologic conditions in the caldera, in which there is a large lake and shallow water table, increase the risk of the quiescent volcano.

  14. One-step synthesis of titanium oxide nanocrystal- rutile by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Evyan Yang Chia [School of Applied Physics, Faculty of Science and Technology, University Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia and Department of Applied Science, Faculty of Science, Engineering and Technology, Nilai University, Persiaran Universiti, P (Malaysia); Zakaria, Sarani; Chia, Chin Hua [School of Applied Physics, Faculty of Science and Technology, University Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

    2014-09-03

    Pure rutile phase titanium oxides (TiO{sub 2}) nanocrystals were synthesized via hydrothermal method with titanium tetrachloride (TiCl{sub 4}) and water (H{sub 2}O) treated in an autoclave. The particle size and phase assemblages were characterized using Scanning electron microscopy (SEM) and X-ray diffraction (XRD) respectively. Band gap energy (E{sub g}) of the nanocrystals was estimated from the Ultra violet – visible light (UV-vis) absorption spectra. It was demonstrated that TiO{sub 2} nanocrystals can be prepared through increasing of temperature and period of treatment. It is believed that the presence of acid chloride (HCl) as by-product during the hydrolysis played an important role in controlling the growth of morphology and crystal structures. The E{sub g} of the samples were estimated from the plot of modified Kubelka-Munk function were in the range of 3.04 – 3.26eV for the samples synthesized at temperature ranging from 50 to 200°C for 16 hours.

  15. Hydrothermal synthesis and luminescence properties of Eu3+and Sm3+codoped BiPO4

    Institute of Scientific and Technical Information of China (English)

    钟剑明; 赵韦人; 蓝立财; 王建青

    2014-01-01

    Eu3+/Sm3+codoped BiPO4 phosphors were synthesized via a facile hydrothermal method with surfactant-free environment. The X-ray diffraction analysis demonstrated that the samples possessed the standard BiPO4 monoclinic structure. Scanning electron microscopy images showed that all samples composed of well-dispersed, micrometer-sized crystals with shuttle-like shape. Energy transfer from Sm3+to Eu3+was confirmed by the luminescence spectra and the decay processes of Sm3+ 4G5/2→6H5/2 emission. Or-ange-red luminescence could be obtained in Eu3+/Sm3+codoped BiPO4 phosphors. The average lifetime of Sm3+ 4G5/2→6H5/2 emis-sion decreased from 2.70 ms in BiPO4:0.03Sm3+ to 2.37 ms in BiPO4:0.03Sm3+,0.05Eu3+. The strong and wide absorption band around 395 nm, originating from both 7F0→5L6 transition of Eu3+and 6H5/2→4K11/2 transition of Sm3+, endowed BiPO4:Eu3+,Sm3+phosphors with the potential application in the fields of near UV-excited white-light-emitting diodes.

  16. Hydrothermal synthesis and photoluminescence of the monophosphate LaPO{sub 4}:Eu(5%)

    Energy Technology Data Exchange (ETDEWEB)

    Ferhi, M.; Horchani-Naifer, K. [Unite de Recherches de Materiaux de Terres Rares, Centre National de Recherches en Sciences des Materiaux, B.P. 95 Hammam-Lif, 2050 (Tunisia); Ferid, M. [Unite de Recherches de Materiaux de Terres Rares, Centre National de Recherches en Sciences des Materiaux, B.P. 95 Hammam-Lif, 2050 (Tunisia)], E-mail: mokhtar.ferid@inrst.rnrt.tn

    2008-11-15

    Hexagonal LaPO{sub 4}.nH{sub 2}O and monoclinic LaPO{sub 4} doped with Eu{sup 3+} powder phosphors were prepared through hydrothermal reaction, respectively, at 100 deg. C and 200 deg. C under fine control of the acidity in the starting materials based on lanthanide oxides and phosphoric acid. X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, thermal treatment, scanning electron microscopy and fluorescence spectroscopy have been used to characterize these materials. The structural, morphological, and luminescent changes of the products due to the heating temperature are studied. The effect of the thermal treatment on the colorimetric characteristic of the red emission of the Eu{sup 3+} was investigated. The Commission Internationale de L'Eclairage (CIE) chromatic coordinates, dominant wavelength, and colour purity were determined, discussed and compared to other products like Eu{sup 3+}-doped zinc aluminate (ZnAl{sub 2}O{sub 4}) and yttrium oxide (Y{sub 2}O{sub 3})

  17. Controllable synthesis of ultrathin vanadium oxide nanobelts via an EDTA-mediated hydrothermal process

    Science.gov (United States)

    Yu-Xiang, Qin; Cheng, Liu; Wei-Wei, Xie; Meng-Yang, Cui

    2016-02-01

    Ultrathin VO2 nanobelts with rough alignment features are prepared on the induction layer-coated substrates by an ethylenediaminetetraacetic acid (EDTA)-mediated hydrothermal process. EDTA acts as a chelating reagent and capping agent to facilitate the one-dimensional (1D) preferential growth of ultrathin VO2 nanobelts with high crystallinities and good uniformities. The annealed induction layer and concentration of EDTA are found to play crucial roles in the formation of aligned and ultrathin nanobelts. Variation in EDTA concentration can change the VO2 morphology of ultrathin nanobelts into that of thick nanoplates. Mild annealing of ultrathin VO2 nanobelts at 350 °C in air results in the formation of V2O5 nanobelts with a nearly unchanged ultrathin structure. The nucleation and growth mechanism involved in the formations of nanobelts and nanoplates are proposed. The ethanol gas sensing properties of the V2O5 nanobelt networks-based sensor are investigated in a temperature range from 100 °C to 300 °C over ethanol concentrations ranging from 3 ppm to 500 ppm. The results indicate that the V2O5 nanobelt network sensor exhibits high sensitivity, good reversibility, and fast response-recovery characteristics with an optimal working temperature of 250 °C. Project supported by the National Natural Science Foundation of China (Grant Nos. 61274074, 61271070, and 61574100).

  18. Hydrothermal synthesis and characterization of hydroxyapatite and fluorhydroxyapatite nano-size powders

    Energy Technology Data Exchange (ETDEWEB)

    Montazeri, Leila; Javadpour, Jafar [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Shokrgozar, Mohammad Ali; Bonakdar, Shahin [National Cell Bank of Iran, Pasteur Institute of Iran, Tehran (Iran, Islamic Republic of); Javadian, Sayfoddin, E-mail: javadpourj@iust.ac.i, E-mail: mashokrgozar@pasteur.ac.i [Department of Biochemistry, Pasteur Institute of Iran, Tehran (Iran, Islamic Republic of)

    2010-08-01

    Pure hydroxyapatite (HAp) and fluoride-containing apatite powders (FHAp) were synthesized using a hydrothermal method. The powders were assessed by x-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscope (SEM) and F-selective electrode. X-ray diffraction results revealed the formation of single phase apatite structure for all the compositions synthesized in this work. However, the addition of a fluoride ion led to a systematic shift in the (3 0 0) peak of the XRD pattern as well as modifications in the FTIR spectra. It was found that the efficiency of fluoride ion incorporation decreased with the increase in the fluoride ion content. Fluorine incorporation efficiency was around 60% for most of the FHAp samples prepared in the current study. Smaller and less agglomerated particles were obtained by fluorine substitution. The bioactivity of the powder samples with different fluoride contents was compared by performing cell proliferation, alkaline phosphatase (ALP) and Alizarin red staining assays. Human osteoblast cells were used to assess the cellular responses to the powder samples in this study. Results demonstrated a strong dependence of different cell activities on the level of fluoridation.

  19. Hydrothermal synthesis of MoO{sub 3} nanobelt-graphene composites

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xiaofei; Ding, Heyi; Zhang, Du; Yan, Xuehua; Lu, Chunyu; Qin, Jieling; Tang, Hua; Song, Haojie [School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Zhang, Rongxian [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China)

    2011-11-15

    A composite of graphene sheets decorated with molybdenum trioxide (MoO{sub 3}) nanobelts has been fabricated via a facile and efficient hydrothermal route in the presence of NaCl. The structure, morphology of these promising composites were investigated by means of field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy and thermogravimetric (TG) analysis. FESEM and TEM studies suggest the presence of uniform crystalline MoO{sub 3} nanobelts and graphene sheets in as-prepared hybrid materials. XRD and Raman results confirm the reduction of graphite oxide (GO) sheets to graphene sheets accompanying by the formation of MoO{sub 3} nanobelts. Moreover, thermal properties of GO and MoO{sub 3} nanobelt-graphene composites reveal that thermal stability of the obtained MoO{sub 3} nanobelt-graphene composites is obviously higher than that of GO due to the transformation of GO sheets to highly stable graphene sheets in the hybrids. This work could provide new insights into the fabrication of high quality MoO{sub 3}-graphene hybrid nanomaterials and facilitate their potential applications in different fields. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  20. Metastable monoclinic ZnMoO4: hydrothermal synthesis, optical properties and photocatalytic performance.

    Science.gov (United States)

    Lv, Li; Tong, Wenming; Zhang, Yanbing; Su, Yiguo; Wang, Xiaojing

    2011-11-01

    Metastable monoclinic ZnMoO4 was successfully synthesized via a hydrothermal route with variation of reaction temperatures and time at pH value of 5.7. Systematic sample characterizations were carried out, including X-ray powder diffraction, scanning electron microscopy, Fourier transformed infrared spectra, UV-visible diffuse reflectance spectra, and photoluminescence spectra. The results show that all as-prepared ZnMoO4 samples were demonstrated to crystallize in a pure-phase of monoclinic wolframite structure. All samples were formed in plate-like morphology. Six IR active vibrational bands were observed in the wave number range of 400-900 cm(-1). The band gap of as-prepared ZnMoO4 was estimated to be 2.86 eV by Tauc equation. Photoluminescence measurement indicates that as-prepared ZnMoO4 exhibits a broad blue-green emission under excitation wavelength of 280 nm at room temperature. Photocatalytic activity of as-prepared ZnMoO4 was examined by monitoring the degradation of methyl orange dye in an aqueous solution under UV radiation of 365 nm. The as-prepared ZnMoO4 obtained at 180 degrees C for 40 h showed the best photocatalytic activity with completing degradation of MO in irradiation time of 120 min. Consequently, monoclinic ZnMoO4 proved to be an efficient near visible light photocatalyst.

  1. A hydrothermal synthesis of Pr3+ doped mesoporous TiO2 for UV light photocatalysis.

    Science.gov (United States)

    Wang, Yong; Chen, Guihua; Shen, Qianhong; Yang, Hui; Li, Liquan; Song, Yanjiang

    2014-07-01

    Pr3+ doped mesoporous TiO2 photocatalysts with a different molar ratio of Pr to Ti were prepared by a hydrothermal method using triblock copolymer as the template. The as-prepared samples were systematically characterized by X-ray diffraction, N2 adsorption-desorption, X-ray photoelectron spectra, transmission electron microscopy and UV-visible diffuse reflectance spectroscopy. The characterizations indicated all the samples had mesoporous structure and narrow pore size distribution. Pr3+ doping enlarged the surface area and decreased the crystallite size. The surface area of the samples varied from 136 to 170 m2/g, and the average crystallite size ranged between 5.04 and 7.60 nm. The effect of Pr3+ doping amount on the photocatalytic activity of mesoporous TiO2 was evaluated by the degradation of methyl orange under UV light irradiation. The results showed that the suitable amount of Pr3+ doped samples exhibited the higher photocatalytic activity than mesoporous TiO2. Among the samples, 1 at.% Pr3+ doped mesoporous TiO2 showed the highest photocatalytic activity.

  2. Amine ligand-based hydrothermal synthesis of Co3O4 nanoparticles, characterization and magnetic study

    Science.gov (United States)

    Mansournia, Mohammadreza; Rakhshan, Narges

    2016-12-01

    Cobalt(II,III) oxid (Co3O4) nanostructures have been successfully synthesized using [Co(NH3)6]Cl3 and [Co(en)3]Cl3 (en: ethylenediamine) as the single precursors via hydrothermal method, and CoCl2·6H2O through a facile ammonia-assisted approach. Indeed, ammine and en ligands, as well as ammonia vapor, act as the sources of hydroxide ion in the preparation of Co3O4 nanoparticles. The structure of products was confirmed by X-ray diffraction (XRD) technique and Fourier-transform infrared (FT-IR) spectroscopy and their morphologies were examined by scanning electron microscopy (SEM). The optical study of the as-prepared Co3O4 nanostructures using UV-Vis diffused reflectance spectroscopy (DRS) exhibited their semiconducting property by revealing one optical band gap in 3.3 eV. Moreover, the vibrating sample magnetometry (VSM) measurements showed a weak ferromagnetic behavior that could be attributed to uncompensated surface spins and/or finite-size effects. Further, the effects of the nature of the precursor, its concentration, temperature and reaction time on the size and morphology of the samples were studied in detail.

  3. Hydrothermal Synthesis and Ammonia Sensing Properties of WO3/Fe2O3 Nanorod Composites

    Science.gov (United States)

    Dien, Nguyen Dac; Phuoc, Luong Huu; Hien, Vu Xuan; Vuong, Dang Duc; Chien, Nguyen Duc

    2017-01-01

    WO3 nanorods (NRs) and α-Fe2O3 NRs were fabricated by hydrothermal treatment. Composites of these materials were created by mixing with ratios of 1:2, 1:1 and 2:1 in weight. Morphology, structure and composition characteristics of the WO3/Fe2O3 NRs composites were characterized by scanning electron microscopy, x-ray diffraction and energy dispersive x-ray spectroscopy analyses. The results of sensing measurements indicated that the sensor based on WO3:Fe2O3 with the ratio of 2:1 exhibited fairly good sensitivity toward NH3 at 300°C and the sensor based on WO3:Fe2O3 with the ratio of 1:1 can be used as a NH3 sensor with an operating temperature of 350°C. Selectivity and response-recovery times are suitable for practical applications. Finally, the mechanism for the improvement in the gas-sensing property was discussed.

  4. Hydrothermal synthesis, photoluminescence and photocatalytic properties of two silver(I) complexes

    Science.gov (United States)

    Yang, Yuan-Yuan; Zhou, Lin-Xia; Zheng, Yue-Qing; Zhu, Hong-Lin; Li, Wen-Ying

    2017-09-01

    Two new dinuclear silver(I) coordination complexes [Ag(Hntph)(tpyz)2/2]n1 and [Ag2(dtrz)2(Hntph)2] 2 (H2ntph=2-nitroterephthalic acid, tpyz=2,3,5-trimethylpyrazine, dtrz=3,5-dimethyl-4H-1,2,4-triazol-4-amine) have been obtained by hydrothermal reactions of Ag(I) salts with H2ntph and various N-donor ligands. Complex 1 exhibits a 2D layer structure constructed by the binuclear Ag2(Hntph)2 units and tpyz ligands. Complex 2 also shows a different binuclear unit Ag2(dtrz)2, which was assembled via hydrogen bonds interactions to a 3D supramolecular architecture. The photocatalytic experiments showed that complex 2 is an excellent visible light candidate for degradation of RhB, and the degradation ratio of RhB reached 91.4% after 7 h under the light of 90 W white LED lamp. Moreover, the photoluminescent properties and the optical band gaps of 1-2 have also been investigated.

  5. Hydrothermal synthesis of C3N4/BiOIO3 heterostructures with enhanced photocatalytic properties.

    Science.gov (United States)

    Wang, Wenjun; Cheng, Hefeng; Huang, Baibiao; Liu, Xiaolei; Qin, Xiaoyan; Zhang, Xiaoyang; Dai, Ying

    2015-03-15

    The C3N4/BiOIO3 composites with heterostructures have been fabricated by simply depositing BiOIO3 on the surface of C3N4 at hydrothermal conditions, using bismuth nitrate and potassium iodate as precursors. C3N4 is an excellent organic semiconductor, which can be excited by visible light. BiOIO3 is a layered bismuth-based compound that has an internal polar field. Coupling C3N4 with BiOIO3 can combine the advantages of the two compounds and obtain better photocatalytic properties. X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Fourier transformation infrared spectra have been carried out to confirm the structures and morphologies of as-prepared products. The absorption properties have been characterized by diffuse reflectance spectra and the photocatalytic activities have been evaluated by photodegradation of methyl orange, Rhodamine B and 2,4-dichlorophenol. Compared with C3N4, all C3N4/BiOIO3 composites exhibit better visible-light-driven photocatalytic properties. It is a synergetic effect that enables the composites to harvest light and promote charge separation, which eventually leads to the enhancement of the photocatalytic efficiencies. Under UV-vis light irradiation, C3N4/BiOIO3 composites also exhibit better activities, and the charge transfer process is similar to a redox mediator-free Z-scheme system. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Synthesis and Characterization of Nanostructure Transition Metal Oxides Extracted from Industrial Waste (EOFD) by Hydrothermal Method

    Science.gov (United States)

    Girisun, T. C. Sabari; Babeela, C.; Vidhya, V.

    2011-10-01

    Electric oil furnace dust (EOFD) is a solid waste generated in the collection of particulate material during steelmaking process in electric and oil furnaces. Over 7 million metric tons dust produced per annum in worldwide creates deep impacts like soil, ground water and ecology pollutions. This article reports the simple one step process for the extraction of nanostructured metal oxides from the industrial waste (EOFD) for the realization of low cost solar applications. By hydrothermal technique valuable metals were obtained in the form of metal oxides. Initially the presence of metals was identified by ICP analysis. XRD analysis confirms the formation of nano structured titanium oxide (TiO) along with traces of iron oxide (Fe2O3). The surface morphology and the particle size were analyzed by SEM analysis. Thus the metal oxides derived could be helpful to reduce the burden on the environment, increase the development of the source nano material and reduce the cost of raw materials for solar cell applications.

  7. One-step hydrothermal synthesis of magnetic Fe3O4 nanoparticles immobilized on polyamide fabric

    Science.gov (United States)

    Zhang, Hui; Zhu, Guoqing

    2012-03-01

    A thin film of nanosized Fe3O4 particles prepared by hydrothermal method was immobilized on the surface of polyamide 6 fiber using ferric trichloride and ferrous chloride as the precursor, N,N-dimethyl formamide as the swelling agent and sodium dodecyl sulfate as the dispersant agent. The morphology, crystalline phase, thermal stability, magnetization properties and chemical structure of polyamide 6 fabric before and after treatments were characterized by means of scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), vibrating sample magnetometer (VSM) and X-ray photoelectron spectroscopy (XPS) techniques. The tensile properties and abrasion resistance were also measured. It was found that the inverse cubic spinel phase of Fe3O4 nanoparticles with an average size 50 nm were synthesized, and synchronously grafted onto polyamide fiber surface. As compared with the original fabric, the onset decomposition temperature of the Fe3O4-coated fabric decreased slightly. The saturation magnetization was measured to be 3.8 emu/g at temperature of 300 K. The tensile properties were enhanced to some extent mainly due to the fabric shrinkage. The abrasion resistance of the Fe3O4-coated fabric behaved well.

  8. Hexamethylenetetramine assisted hydrothermal synthesis of BiPO4 and its electrochemical properties for supercapacitors

    Science.gov (United States)

    Nithya, V. D.; Kalai Selvan, R.; Vasylechko, Leonid

    2015-11-01

    The well defined microstructures of BiPO4 were successfully synthesized by the facile hexamethylenetetramine (HMT) assisted hydrothermal method. The low temperature monoclinic BiPO4 structure with space group P21/n, were obtained from X-ray diffraction (XRD) for the pristine and HMT-assisted BiPO4 with 1, 3, 5 and 10 mmole concentration. A transformation from low temperature monazite-type phase to the high temperature SbPO4-type phase of BiPO4 was observed at the 10 mmole concentration. There was a variation in the morphology from polyhedron to octahedra-like and finally into cube shape upon an increase in concentration of HMT. The role of reaction time in the morphology of BiPO4 particles was investigated. The selected area electron diffraction (SAED) pattern elucidated the ordered dot pattern and the calculated d-spacing revealed the formation of BiPO4. An increased specific capacitance of HMT assisted materials (202 F/g) compared with pristine BiPO4 (89 F/g) at 5 mA/cm2 was observed upon morphological variation due to HMT addition.

  9. Hydrothermal Synthesis, Microstructure and Photoluminescence of Eu3+-Doped Mixed Rare Earth Nano-Orthophosphates

    Directory of Open Access Journals (Sweden)

    Yan Bing

    2010-01-01

    Full Text Available Abstract Eu3+-doped mixed rare earth orthophosphates (rare earth = La, Y, Gd have been prepared by hydrothermal technology, whose crystal phase and microstructure both vary with the molar ratio of the mixed rare earth ions. For LaxY1–xPO4: Eu3+, the ion radius distinction between the La3+ and Y3+ is so large that only La0.9Y0.1PO4: Eu3+ shows the pure monoclinic phase. For LaxGd1–xPO4: Eu3+ system, with the increase in the La content, the crystal phase structure of the product changes from the hexagonal phase to the monoclinic phase and the microstructure of them changes from the nanorods to nanowires. Similarly, YxGd1–xPO4: Eu3+, Y0.1Gd0.9PO4: Eu3+ and Y0.5Gd0.5PO4: Eu3+ samples present the pure hexagonal phase and nanorods microstructure, while Y0.9Gd0.1PO4: Eu3+ exhibits the tetragonal phase and nanocubic micromorphology. The photoluminescence behaviors of Eu3+ in these hosts are strongly related to the nature of the host (composition, crystal phase and microstructure.

  10. 3D structure and formation of hydrothermal vent complexes in the Møre Basin

    Science.gov (United States)

    Kjoberg, Sigurd; Schmiedel, Tobias; Planke, Sverre; Svensen, Henrik H.; Galland, Oliver; Jerram, Dougal A.

    2016-04-01

    The mid-Norwegian Møre margin is regarded as a type example of a volcanic rifted margin, with its formation usually related to the influence of the Icelandic plume activity. The area is characterized by the presence of voluminous basaltic complexes such as extrusive lava sequences, intrusive sills and dikes, and hydrothermal vent complexes within the Møre Basin. Emplacement of hydrothermal vent complexes is accommodated by deformation of the host rock. The edges of igneous intrusions mobilize fluids by heat transfer into the sedimentary host rock (aureoles). Fluid expansion may lead to formation of piercing structures due to upward fluid migration. Hydrothermal vent complexes induce bending of overlying strata, leading to the formation of dome structures at the paleo-surface. These dome structures are important as they indicate the accommodation created for the intrusions by deformation of the upper layers of the stratigraphy, and may form important structures in many volcanic margins. Both the morphological characteristics of the upper part and the underlying feeder-structure (conduit-zone) can be imaged and studied on 3D seismic data. Seismic data from the Tulipan prospect located in the western part of the Møre Basin have been used in this study. The investigation focusses on (1) the vent complex geometries, (2) the induced surface deformation patterns, (3) the relation to the intrusions (heat source), as well as (4) the emplacement depth of the hydrothermal vent complexes. We approach this by doing a detailed 3D seismic interpretation of the Tulipan seismic data cube. The complexes formed during the initial Eocene, and are believed to be a key factor behind the rapid warming event called the Paleocene-Eocene thermal maximum (PETM). The newly derived understanding of age, eruptive deposits, and formation of hydrothermal vent complexes in the Møre Basin enables us to contribute to the general understanding of the igneous plumbing system in volcanic basins and

  11. Bismuth Molybdate Catalysts Prepared by Mild Hydrothermal Synthesis: Influence of pH on the Selective Oxidation of Propylene

    Directory of Open Access Journals (Sweden)

    Kirsten Schuh

    2015-09-01

    Full Text Available A series of bismuth molybdate catalysts with relatively high surface area was prepared via mild hydrothermal synthesis. Variation of the pH value and Bi/Mo ratio during the synthesis allowed tuning of the crystalline Bi-Mo oxide phases, as determined by X-ray diffraction (XRD and Raman spectroscopy. The pH value during synthesis had a strong influence on the catalytic performance. Synthesis using a Bi/Mo ratio of 1/1 at pH ≥ 6 resulted in γ-Bi2MoO6, which exhibited a better catalytic performance than phase mixtures obtained at lower pH values. However, a significantly lower catalytic activity was observed at pH = 9 due to the low specific surface area. γ-Bi2MoO6 synthesized with Bi/Mo = 1/1 at pH = 6 and 7 exhibited relatively high surface areas and the best catalytic performance. All samples prepared with Bi/Mo = 1/1, except samples synthesized at pH = 1 and 9, showed better catalytic performance than samples synthesized with Bi/Mo = 2/3 at pH = 4 and 9 and γ-Bi2MoO6 synthesized by co-precipitation at pH = 7. At temperatures above 440 °C, the catalytic activity of the hydrothermally synthesized bismuth molybdates started to decrease due to sintering and loss of surface area. These results support that a combination of the required bismuth molybdate phase and a high specific surface area is crucial for a good performance in the selective oxidation of propylene.

  12. Carbon Isotopes of Alkanes in Hydrothermal Abiotic Organic Synthesis Processes at High Temperatures and Pressures: An Experimental Study

    Science.gov (United States)

    Fu, Qi; Socki, Richard A.; Niles, Paul B.

    2010-01-01

    Observation of methane in the Martian atmosphere has been reported by different detection techniques [1-4]. With more evidence showing extensive water-rock interaction in Martian history [5-7], abiotic formation by Fischer-Tropsch Type (FTT) synthesis during serpentization reactions may be one possible process responsible for methane generation on Mars [8, 9]. While the experimental studies performed to date leave little doubt that chemical reactions exist for the abiotic synthesis of organic compounds by mineral surface-catalyzed reactions [10-12], little is known about the reaction pathways by which CO2 and/or CO are reduced under hydrothermal conditions. Carbon and hydrogen isotope measurements of alkanes have been used as an effective tool to constrain the origin and reaction pathways of hydrocarbon formation. Alkanes generated by thermal breakdown of high molecular weight organic compounds have carbon and hydrogen isotopic signatures completely distinct from those formed abiotically [13-15]. Recent experimental studies, however, showed that different abiogenic hydrocarbon formation processes (e.g., polymerization vs. depolymerization) may have different carbon and hydrogen isotopic patterns [16]. Results from previous experiments studying decomposition of higher molecular weight organic compounds (lignite) also suggested that pressure could be a crucial factor affecting fractionation of carbon isotopes [17]. Under high pressure conditions, no experimental data are available describing fractionation of carbon isotope during mineral catalyzed FTT synthesis. Thus, hydrothermal experiments present an excellent opportunity to provide the requisite carbon isotope data. Such data can also be used to identify reaction pathways of abiotic organic synthesis under experimental conditions.

  13. A catechol-like phenolic ligand-functionalized hydrothermal carbon: One-pot synthesis, characterization and sorption behavior toward uranium

    Energy Technology Data Exchange (ETDEWEB)

    Li, Bo; Ma, Lijian; Tian, Yin; Yang, Xiaodan; Li, Juan; Bai, Chiyao; Yang, Xiaoyu; Zhang, Shuang; Li, Shoujian, E-mail: sjli000616@scu.edu.cn; Jin, Yongdong, E-mail: jinyongdong@scu.edu.cn

    2014-04-01

    Highlights: • A new catechol-like ligand-functionalized hydrothermal carbon sorbent is synthesized. • A combination of bayberry tannin and glyoxal is firstly used as starting materials. • Simple, economically viable and environment-friendly synthesis method. • The sorbent exhibits high sorption capacity and distinct selectivity for uranium. - Abstract: We proposed a new approach for preparing an efficient uranium-selective solid phase extractant (HTC-btg) by choosing bayberry tannin as the main building block and especially glyoxal as crosslinking agent via a simple, economic, and green one-pot hydrothermal synthesis. The results of characterization and analysis show that after addition of glyoxal into only bayberry tannin-based hydrothermal reaction system, the as-synthesized HTC-btg displayed higher thermal stability, larger specific surface area and more than doubled surface phenolic hydroxyl groups. The sorption behavior of the sorbents toward uranium under various conditions was investigated in detail and the results indicated that the process is fast, endothermic, spontaneous, and pseudo-second-order chemisorption. The U(VI) sorption capacity reached up to 307.3 mg g{sup −1} under the current experimental conditions. The selective sorption in a specially designed multi-ion solution containing 12 co-existing cations over the range of pH 1.0–4.5 shown that the amount of uranium sorbed accounts for about 53% of the total sorption amount at pH 4.5 and distinctively about 85%, unreported so far to our knowledge, at pH 2.0. Finally, a possible mechanism involving interaction between uranyl ions and phenolic hydroxyl groups on HTC-btg was proposed.

  14. Post-impact hydrothermal system geochemistry and mineralogy: Rochechouart impact structure, France.

    Science.gov (United States)

    Simpson, Sarah

    2014-05-01

    Hypervelocity impacts generate extreme temperatures and pressures in target rocks and may permanently alter them. The process of cratering is at the forefront of research involving the study of the evolution and origin of life, both on Mars and Earth, as conditions may be favourable for hydrothermal systems to form. Of the 170 known impact structures on Earth, over one-third are known to contain fossil hydrothermal systems [1]. The introduction of water to a system, when coupled with even small amounts of heat, has the potential to completely alter the target or host rock geochemistry. Often, the mineral assemblages produced in these environments are unique, and are useful indicators of post-impact conditions. The Rochechouart impact structure in South-Central France is dated to 201 ± 2 Ma into a primarily granitic target [2]. Much of the original morphological features have been eroded and very little of the allochthonous impactites remain. This has, however, allowed researchers to study the shock effects on the lower and central areas of the structure, as well as any subsequent hydrothermal activity. Previous work has focused on detailed classification of the target and autochthonous and allochthonous impactites [3, 4], identification of the projectile [5], and dating the structure using Ar-isotope techniques [2]. Authors have also noted geochemical evidence of K-metasomatism, which is pronounced throughout all lithologies as enrichment in K2O and depletion in CaO and Na2O [3, 4, 5]. This indicates a pervasive hydrothermal system, whose effects throughout the structure have yet to be studied in detail, particularly in those parts at and below the transient floor. The purpose of this study is to classify the mineralogical and geochemical effects of the hydrothermal system. Samples were collected via permission from the Réserve Naturelle de l'Astroblème de Rochechouart-Chassenon [6]. Sample selection was based on the presence of secondary mineralization in hand

  15. Nanostructural evolution of one-dimensional BaTiO₃ structures by hydrothermal conversion of vertically aligned TiO₂ nanotubes.

    Science.gov (United States)

    Muñoz-Tabares, J A; Bejtka, K; Lamberti, A; Garino, N; Bianco, S; Quaglio, M; Pirri, C F; Chiodoni, A

    2016-03-28

    The use of TiO2 nanotube (NT) arrays as templates for hydrothermal conversion of one-dimensional barium titanate (BaTiO3) structures is considered a promising synthesis approach, even though the formation mechanisms are not yet fully understood. Herein we report a nanostructural study by means of XRD and (HR)TEM of high aspect ratio TiO2-NTs hydrothermally converted into BaTiO3. The nanostructure shows two different and well-defined regions: at the top the conversion involves complete dissolution of NTs and subsequent precipitation of BaTiO3 crystals by homogeneous nucleation, followed by the growth of dendritic structures by aggregation and oriented attachment mechanisms. Instead, at the bottom, the low liquid/solid ratio, due to the limited amount of Ba solution that infiltrates the NTs, leads to the rapid crystallization of such a solution into BaTiO3, thus allowing the NTs to act as a template for the formation of highly oriented one-dimensional nanostructures. The in-depth analysis of the structural transformations that take place during the formation of the rod-like arrays of BaTiO3 could help elucidate the conversion mechanism, thus paving the way for the optimization of the synthesis process in view of new applications in energy harvesting devices, where easy and low temperature processing, controlled composition, morphology and functional properties are required.

  16. Hydrothermal synthesis of fine stabilized superparamagnetic nanoparticles of Zn{sup 2+} substituted manganese ferrite

    Energy Technology Data Exchange (ETDEWEB)

    Zahraei, Maryam, E-mail: zahraee_maryam@yahoo.com [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Monshi, Ahmad [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Morales, Maria del Puerto [Instituto de Ciencia de Materiales de Madrid, ICMM/CSIC, Cantoblanco, 28049 Madrid (Spain); Shahbazi-Gahrouei, Daryoush [Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan 81746-734615 (Iran, Islamic Republic of); Amirnasr, Mehdi [Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Behdadfar, Behshid [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

    2015-11-01

    Superparamagnetic Zn{sup 2+} substituted manganese ferrite Mn{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} (x=0.3, 0.35, 0.4 and 0.45) nanoparticles (NPs) were synthesized via a direct, efficient and environmental friendly hydrothermal method. The synthesized NPs were characterized by X-ray powder diffractometry (XRD), transmission electron microscopy (TEM), thermo-gravimetry (TG) and vibrating sample magnetometry (VSM). The effects of various parameters such as the pH of reaction mixture, time and temperature of hydrothermal treatment and Zn substitution on the spinel phase formation, the magnetization, and the size of resulting NPs are discussed. The Zn{sup 2+} substituted manganese ferrite NPs obtained from hydrothermal process crystallized mainly in the spinel phase. Nevertheless, without citrate ions, the hematite phase appeared in the product. The monophase Zn{sup 2+} substituted manganese ferrite NPs hydrothermally prepared in the presence of citric acid had mean particle size of 7 nm and a narrow size distribution. Furthermore, the synthesized NPs can be used to prepare ferrofluids for biomedical applications due to their small size, good stability in aqueous medium (pH 7) and also high magnetization value. - Highlights: • Single phase Mn–Zn ferrite NPs were synthesized by hydrothermal method. • Substitution of Zn in Mn-ferrite increased Ms. • These Mn–Zn ferrite NPs can be used for biomedical applications.

  17. Weathering of post-impact hydrothermal deposits from the Haughton impact structure: implications for microbial colonization and biosignature preservation.

    Science.gov (United States)

    Izawa, M R M; Banerjee, Neil R; Osinski, G R; Flemming, R L; Parnell, J; Cockell, C S

    2011-01-01

    Meteorite impacts are among the very few processes common to all planetary bodies with solid surfaces. Among the effects of impact on water-bearing targets is the formation of post-impact hydrothermal systems and associated mineral deposits. The Haughton impact structure (Devon Island, Nunavut, Canada, 75.2 °N, 89.5 °W) hosts a variety of hydrothermal mineral deposits that preserve assemblages of primary hydrothermal minerals commonly associated with secondary oxidative/hydrous weathering products. Hydrothermal mineral deposits at Haughton include intra-breccia calcite-marcasite vugs, small intra-breccia calcite or quartz vugs, intra-breccia gypsum megacryst vugs, hydrothermal pipe structures and associated surface "gossans," banded Fe-oxyhydroxide deposits, and calcite and quartz veins and coatings in shattered target rocks. Of particular importance are sulfide-rich deposits and their associated assemblage of weathering products. Hydrothermal mineral assemblages were characterized structurally, texturally, and geochemically with X-ray diffraction, micro X-ray diffraction, optical and electron microscopy, and inductively coupled plasma atomic emission spectroscopy. Primary sulfides (marcasite and pyrite) are commonly associated with alteration minerals, including jarosite (K,Na,H(3)O)Fe(3)(SO(4))(2)(OH)(6), rozenite FeSO(4)·4(H(2)O), copiapite (Fe,Mg)Fe(4)(SO(4))(6)(OH)(2)·20(H(2)O), fibroferrite Fe(SO(4))(OH)·5(H(2)O), melanterite FeSO(4)·7(H(2)O), szomolnokite FeSO(4)·H(2)O, goethite α-FeO(OH), lepidocrocite γ-FeO(OH) and ferrihydrite Fe(2)O(3)·0.5(H(2)O). These alteration assemblages are consistent with geochemical conditions that were locally very different from the predominantly circumneutral, carbonate-buffered environment at Haughton. Mineral assemblages associated with primary hydrothermal activity, and the weathering products of such deposits, provide constraints on possible microbial activity in the post-impact environment. The initial period of

  18. Hydrothermal synthesis and characterization of new hybrid open-framework indium phosphate-oxalates

    Institute of Scientific and Technical Information of China (English)

    CHEN Zhenxia; WENG Linhong; CHEN Jinxi; ZHAO Dongyuan

    2004-01-01

    Three new hybrid open-framework indium phosphate-oxalates,Ⅰ, Na[InPO4(C2O4)0.5]·H2OⅡ, [C2N2- H10]0.5[InPO4(C2O4)0.5]Ⅲ, [C3N2H12]0.5[In2(PO4)(HPO4)(C2- O4)]·H2O have been hydrothermally synthesized by using organic amines such as ethylamine, 1,3-diaminopropane and alkali metal ions such as Na+ as structure-directing agents (SDA). The structures of these compounds were characterized by single crystal X-ray diffraction. The structure of Ⅰ consists of InO6 octahedra that are linked by phosphate and oxalate groups to generate a three-dimensional framework with intersecting 8-membered ring (MR) channels parallel to the [100] and [010] directions. The structure of Ⅱ is similar to that of I except that its guest species are protonated ethylamines. Ⅲ is built from indiumphosphate double-six-rings second building units linked by oxalate units, resulting in large circular 16 MR channels. Single crystal X-ray diffraction measurements show that the SDA of Ⅰ-Ⅲ are located in their channels. Crystal data for these three indium phosphate-oxalates are as follows: Ⅰ, triclinic, space group: P-1 (No. 2), a = 5.5662(17)(A), b = 6.454(2) (A), c = 8.966(3) (A), α = 102.609(4)°, β = 107.319(3)°, γ = 94.426(4)°, V = 296.56(16) (A)3, Z = 2, M = 294.81, Ρcalcu = 3.301 g/cm3, R1 = 0.0275, wR2 = 0.0731. Ⅱ, triclinic, space group: P-1 (No. 2), a = 5.653(4) (A), b = 6.627(4) (A), c = 9.391(8) (A), α = 70.788(8)°, β = 75.836(12)°, γ = 89.681(9)°, V = 321.1(4) (A)3, Z = 2, M = 283.85, Ρcalcu = 2.936 g/cm3, R1= 0.0664, wR2 = 0.1572. Ⅲ, orthorhombic, space group: Pccm (No. 49), a = 10.350(2) (A), b = 12.190(2) (A), c = 13.000(3) (A), V = 1640.2(6) (A)3, Z = 4, M =272.32, Ρcalcu = 2.206 g/cm3, R1=0.0691, wR2 = 0.1831.

  19. Synthesis and characterization of a nickel selenide series via a hydrothermal process

    Science.gov (United States)

    Sobhani, Azam; Salavati-Niasari, Masoud

    2014-01-01

    A series of nickel selenides (NiSe and NiSe2) has been successfully synthesized from the reaction of SeCl4 with NiCl2ṡ6H2O in the presence of cetyltrimethyl ammonium bromide (CTAB) as surfactant and hydrazine hydrate (N2H4ṡH2O) as reductant at 180 °C for 12 h through a simple hydrothermal method. The morphology, phase structure and composition of NixSey can be controlled by adjusting the Ni/Se ratio of the raw materials, the quantity of reductant, the reaction temperature and so forth. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS) analysis. It was found that when the ratio of Ni/Se is 1:1 or 3:2, flower-like assemblies of NiSe nanosheets are formed, at 180 °C for 12 h. When the ratio of Ni/Se is 1:2 at 180 °C, the products are found to be the mixture of hexagonal NiSe and cubic NiSe2. With decrease of nickel content in molar ratio of 1:2 (Ni:Se), nanospheres are agglomerated and microstructures are formed. With the reaction temperature decreasing from 180 °C to 120 °C, we reach pure NiSe2 nanoparticles. The formation mechanism of the nickel selenides has been investigated in detail by means of XRD and SEM analyses.

  20. Microwave assisted hydrothermal synthesis and characterization of ZnO–TNT composites

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Sung Hun; Gyawali, Gobinda; Adhikari, Rajesh [Department of Metallurgy and Materials Engineering, SunMoon University, Asan (Korea, Republic of); Kim, Tae Ho [Department of Environmental Engineering, SunMoon University, Asan (Korea, Republic of); Lee, Soo Wohn, E-mail: swlee@sunmoon.ac.kr [Department of Environmental Engineering, SunMoon University, Asan (Korea, Republic of)

    2014-06-01

    TiO{sub 2} nanotubes with different contents of ZnO (3–40 wt.% ZnO) have been successfully synthesized by microwave assisted hydrothermal process by using commercial TiO{sub 2}-P25 as a precursor. The phase and crystallinity of the obtained ZnO–TNT were analyzed by X-ray Diffraction (XRD). The surface area of the ZnO–TNT was determined by BET method. The effect of the different contents of ZnO on morphology of TiO{sub 2} nanotubes was investigated by SEM and TEM. Optical properties and band gap energy of ZnO–TNT were calculated by using UV–vis DRS spectroscopy and modified Kubelka–Munk equation. Photocatalytic performance of ZnO–TNT was investigated by degradation of rhodamine B (RhB) dye under UV and visible light irradiation. Increasing ZnO content in TNT gradually decreased the diameter and length of nanotubes. Furthermore, addition of 40 wt.% ZnO into the TNT exceeded the saturation limit of ion exchangeability of Zn{sup 2+} and Na{sup +} ions and aggregation of finely dispersed ZnO particles on the surface of TNT were observed. The ZnO–TNT has shown relatively larger band gap energies than that of TiO{sub 2}-P25. However, ZnO–TNT has shown considerable increase in photo-activity for degradation of RhB dye in visible light as compared to UV light irradiation. - Highlights: • ZnO–TNT composites were successfully synthesized. • Investigation of the structural changes in the composites is confirmed. • The photocatalytic activity of the composites was studied. • Composites exhibited better performance under visible light than in UV light.

  1. Conformal BaTiO3 Films with High Piezoelectric Coupling through an Optimized Hydrothermal Synthesis.

    Science.gov (United States)

    Zhou, Zhi; Bowland, Christopher C; Patterson, Brendan A; Malakooti, Mohammad H; Sodano, Henry A

    2016-08-24

    Two-dimensional (2D) ferroelectric films have vast applications due to their dielectric, ferroelectric, and piezoelectric properties that meet the requirements of sensors, nonvolatile ferroelectric random access memory (NVFeRAM) devices, and micro-electromechanical systems (MEMS). However, the small surface area of these 2D ferroelectric films has limited their ability to achieve higher memory storage density in NVFeRAM devices and more sensitive sensors and transducer. Thus, conformally deposited ferroelectric films have been actively studied for these applications in order to create three-dimensional (3D) structures, which lead to a larger surface area. Most of the current methods developed for the conformal deposition of ferroelectric films, such as metal-organic chemical vapor deposition (MOCVD) and plasma-enhanced vapor deposition (PECVD), are limited by high temperatures and unstable and toxic organic precursors. In this paper, an innovative fabrication method for barium titanate (BaTiO3) textured films with 3D architectures is introduced to alleviate these issues. This fabrication method is based on converting conformally grown rutile TiO2 nanowire arrays into BaTiO3 textured films using a simple two-step hydrothermal process which allows for thickness-controlled growth of conformal films on patterned silicon wafers coated with fluorine-doped tin oxide (FTO). Moreover, the processing parameters have been optimized to achieve a high piezoelectric coupling coefficient of 100 pm/V. This high piezoelectric response along with high relative dielectric constant (εr = 1600) of the conformally grown textured BaTiO3 films demonstrates their potential application in sensors, NVFeRAM, and MEMS.

  2. Hydrothermal synthesis and characterization of two novel inorganic-organic hybrid materials

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    By using different organic ligands, two 3D inorganic-organic hybrid compounds Co(C4H4N2)(VO3)2 1 and Co(C12H12N2)(VO3)2 2 were synthesized by hydrothermal reaction and characterized by X-ray crystallography. Crystal data: 1.crystal system orthorhombic, space group Pnna, a=10.188(2) (A), b=11.497(2)(A), c=7.3975(15)(A), V=866.5(3) (A)3, Z=4, Dcalcd=2.705 g/cm3; 2. crystal system triclinic, space group P1- (No. 2), a=8.3190(17) (A), b=8.4764(17)(A), c=11.183(2)(A), α=95.48(3)°,β=92.03(3)°, γ=107.24(3)°, V=748.0(3) (A)3, Z=2, Dcalcd=1.958 g/cm3. The framework of compound 1 contains both {Co(C4H4N2)}and infinite metavanadate chains. Crystal structure of compound 2 is constructed with inorganic {CoV2O6} layers across-linked by organic 1,2-bis(4-pyridyl) ethane ligands. The two compounds are thermally stable to approximately 410 ℃ and 350 ℃, respectively. Their optical band gaps are determined to be 2.13 eV and 2.12 eV by UV-VIS-NIR diffuse reflectance spectra, which revealed their nature of semiconductor and optical absorption features.

  3. 水热法合成硅孔雀石的研究%Study on Hydrothermal Synthesis of Chrysocolla

    Institute of Scientific and Technical Information of China (English)

    赵娟; 刘云清; 刘常青; 戴宽

    2013-01-01

    Chrysocolla was prepared by hydrothermal synthesis method with sodium silicate solution and copper nitrate solution as reactants.The effects of dropping order of reactants,stirring reaction temperature,temperature and time of hydrothermal reaction,and mineralizer on synthesis were investigated.The products were characterized by IR,XRD and chemical analysis.The results show that high-purity sky-blue chrysocolla is prepared under the following conditions including sodium silicate solution dropped into copper nitrate solution,stirring reaction temperature of 35 ℃,stirring reaction time of 4 h,dosage of mineralizer of 0.1 mol/L Na2SiO3 of 40 mL and 0.1 mol/L NaOH of 20 mL,hydrothermal reaction temperature of 120 ℃,and hydrothermal reaction time of 6 h.%以硅酸钠溶液和硝酸铜溶液为原料,采用水热合成法合成硅孔雀石,考察了制备前驱体时反应物滴加顺序、反应温度、水热结晶温度、反应时间和矿化剂等因素对硅孔雀石合成的影响,采用红外、XRD、化学分析等手段对产物进行表征.结果表明,在硅酸钠溶液中滴入硝酸铜溶液,反应温度为35℃,时间4h,加入40 mL质量浓度为0.1 mol/L的Na2SiO3和20 mL质量浓度为0.1 mol/L的NaOH混合液为矿化剂,水热反应温度120℃,时间6h的条件下,得到了纯度较高的天蓝色硅孔雀石.

  4. Growth history of hydrothermal chimneys at EPR 9―10°N: A structural and mineralogical study

    Institute of Scientific and Technical Information of China (English)

    PENG Xiaotong; ZHOU Huaiyang

    2005-01-01

    Based on structural and mineralogical characteristics of four hydrothermal chimney samples collected by submersible Alvin, growth history and formation environment of hydrothermal chimney at EPR 9―10°N are established. It is shown that there occur two types of hydrothermal chimney with different deposition environments at EPR 9―10°N according to differences in their shape, structure and mineral assemblage: type I chimney forms in an environment with high temperature, low pH and strong reducing hydrothermal focus flow and type II chimney forms in a relatively low temperature, high pH and rich Zn hydrothermal environment. Growth of type I chimney begins with the formation of anhydrite. Subsequently deposition of Cu-Fe-Zn sulphide in various directions of chimneys decides the final structure of this type of chimney. According to observation and analysis of mineral assemblages, the formation process of type I chimney could be divided into three stages from early, middle to late. Changes of temperature and major chemical reaction type in the process of hydrothermal chimney formation are also deduced. Different from type I chimney, quenching crystalline of pyrite and/or crystalline of sphalerite provide the growth foundation of type II chimney in the early stage of chimney formation.

  5. Hydrothermal synthesis, off-axis electron holography and magnetic properties of Fe3O4 nanoparticles

    DEFF Research Database (Denmark)

    Almeida, Trevor P.; Muxworthy, Adrian R.; Williams, Wyn;

    2014-01-01

    The hydrothermal synthesis of Fe3O4 nanoparticles (NPs) (<50 nm) from mixed FeCl3 / FeCl2 precursor solution at pH ~ 12 has been confirmed using complementary characterisation techniques of transmission electron microscopy and X-ray diffractometry. Off-axis electron holography allowed for visuali...

  6. Fabrication of Zeolite A Rods with Irregular Macropores by Self-assembly of Zeolite A Microcrystals Using Microwave-assisted Hydrothermal Synthesis

    Institute of Scientific and Technical Information of China (English)

    程志林; 万惠霖; 刘赞

    2004-01-01

    Zeolite A rods by self-assembly of zeolite A microcrystal were successfully synthesized by microwave-assisted hydrothermal synthesis. The average size of zeolite crystals consisting of self-assembling materials was about 300 nm and the length of zeolite rods was in the range of 15-30 μm.

  7. Controlled synthesis of BiVO{sub 4} with multiple morphologies via an ethylenediamine-assisted hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Xuemei, E-mail: qixuemei@shiep.edu.cn [School of Chemistry and Chemical Engineering, Shanghai Key Lab of Electrical Insulation and Thermal Aging, Shanghai Jiao Tong University, Shanghai 200240 (China); School of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090 (China); Zhu, Xinyuan [School of Chemistry and Chemical Engineering, Shanghai Key Lab of Electrical Insulation and Thermal Aging, Shanghai Jiao Tong University, Shanghai 200240 (China); Wu, Jiang, E-mail: wujiang@shiep.edu.cn [School of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090 (China); School of Energy and Mechanical Engineering, Shanghai University of Electric Power, Shanghai 200090 (China); Wu, Qiang [School of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090 (China); Li, Xian [School of Energy and Mechanical Engineering, Shanghai University of Electric Power, Shanghai 200090 (China); Gu, Miaoli [School of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090 (China)

    2014-11-15

    Graphical abstract: BiVO{sub 4} samples with various morphologies were synthesized via a simple ethylenediamine (EN) assisted hydrothermal route. One of the mixed crystal phase with spherical and porous morphology showed excellent photocatalytic activity and about 90% Rhodamine B was degraded after 140 min visible light irradiation. - Highlights: • BiVO{sub 4} samples with various morphologies were synthesized by hydrothermal method. • Ethylenediamine mainly acts as alkaline source to adjust pH values of precursor. • BiVO{sub 4} with spherical morphology has excellent photocatalytic activity. - Abstract: In this work, BiVO{sub 4} particles with different crystal structures and morphologies including hexahedral, spherical porous and hyperbranched ones were fabricated in the presence of ethylenediamine by hydrothermal process. The as-fabricated samples were well characterized by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy and ultraviolet–visible absorption spectroscopy. The results showed that the morphology and crystal structure of BiVO{sub 4} particles could be well controlled by only changing the ethylenediamine content in the deionized water solution. Photocatalytic activity of the samples was evaluated by the degradation of Rhodamine B under visible-light irradiation. It was shown that BiVO{sub 4} sample with spherical porous morphology and mixed crystal phase exhibited the best photocatalytic performance after optimizing the ethylenediamine content. The best degradation ratio of Rhodamine B could reach about 87% after 140 min visible-light irradiation.

  8. Synthesis of Fe-Ti-MCM-48 from silatrane precursor via sol-gel process and its hydrothermal stability

    Energy Technology Data Exchange (ETDEWEB)

    Maneesuwan, Hussaya; Chaisuwan, Thanyalak; Wongkasemjit, Sujitra, E-mail: dsujitra@chula.ac.th

    2014-08-01

    A series of bimetallic Fe–Ti-MCM-48 materials was successfully synthesized via sol–gel method using cetyltrimethylammonium bromide (CTAB) as a template and silatrane, iron (III) chloride, and titanium (IV) isopropoxide as silica, iron, and titanium sources, respectively. Scanning electron microscopy (SEM) showed the truncated octahedron morphology of Fe–Ti-MCM-48.X-ray diffraction (XRD) patterns showed well-defined, order cubic mesoporous structures. X-ray fluorescence (XRF) revealed the total metal content of the final product. UV–visible absorption spectra confirmed both iron (Fe{sup 3+}) and cerium (Ti{sup 4+}) species highly dispersed in the framework, while N{sub 2} adsorption/desorption measurements indicated a high specific surface area. As metal content increased, the mesoporous order and surface area decreased. The synthesized Fe–Ti-MCM-48 with 0.01Fe/Si and 0.01Ti/Si ratio still retained a cubic structure after hydrothermal treatment at 100 °C for 72 h. - Highlights: • Fe–Ti-MCM-48 mesoporous molecular sieves were successfully synthesized. • Bimetallic Fe–Ti-MCM-48 with 0.01Fe/Si and 0.01Ti/Si ratio had highly hydrothermal stability. • The higher titanium content led to the lower specific surface area and hydrothermal stability.

  9. Hydrothermal synthesis of core–shell TiO{sub 2} to enhance the photocatalytic hydrogen evolution

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Jinghui; Zhou, Han; Zhang, Fan; Fan, Tongxiang, E-mail: txfan@sjtu.edu.cn; Zhang, Di

    2016-04-15

    Graphical abstract: Core–shell TiO{sub 2} with interior cavity was synthesized by a hydrothermal approach to enhance the photocatalytic performance. - Highlights: • Core–shell TiO{sub 2} with interior cavity can be synthesized by hydrothermal approach. • Multiple reflection of incident light in cavity can increase the absorption. • Rutile can optimize the bandgap and delay the charge recombination. - Abstract: A hydrothermal approach was designed to synthesize core–shell TiO{sub 2} with interior cavity by making sodium dodecyl sulfonate (SDS) as the surfactant and the mixture of water and ethanol as the solvent. The control experiment of solvent reveals ethanol and water are responsible for the formation of sphere and interior cavity, respectively. Besides, SDS can assist the growth of core–shell structure, and the sizes of sphere and interior cavity can be tuned by regulating the reaction time or temperature. UV–vis absorption proves core–shell structure with interior cavity can increase the absorption of incident light to enhance the optical activity of final product. The calculated bandgap and photoluminescence (PL) analyses reveal the coexistence of rutile in final product can optimize the bandgap to 3.03 eV and delay the charge recombination. As a result, an effective photocatalytic hydrogen evolution under full spectrum irradiation can be harvested by the as-synthesized core–shell spheres to reach a quantum yield, approximately 9.57% at 340 nm wavelength.

  10. Hydrothermal synthesis of NaEuF4 spindle-like nanocrystals

    Indian Academy of Sciences (India)

    Zhi-Jun Wang; Feng Tao; Wei-Li Cai; Lian-Zeng Yao; Xiao-Guang Li

    2011-12-01

    NaEuF4 spindle-like nanocrystals have been synthesized through a simple hydrothermal method. The nanocrystals were well crystallized and exhibited fine morphology, as indicated by X-ray diffraction, transmission electron microscope and selected area electron diffractometer. The luminescence properties of these NaEuF4 products were investigated.

  11. Hydrothermal Synthesis of Hydroxyapatite Nanorods for Rapid Formation of Bone-Like Mineralization

    Science.gov (United States)

    Hoai, Tran Thanh; Nga, Nguyen Kim; Giang, Luu Truong; Huy, Tran Quang; Tuan, Phan Nguyen Minh; Binh, Bui Thi Thanh

    2017-08-01

    Hydroxyapatite (HAp) is an excellent biomaterial for bone repair and regeneration. The biological functions of HAp particles, such as biomineralization, cell adhesion, and cell proliferation, can be enhanced when their size is reduced to the nanoscale. In this work, HAp nanoparticles were synthesized by the hydrothermal technique with addition of cetyltrimethylammonium bromide (CTAB). These particles were also characterized, and their size controlled by modifying the CTAB concentration and hydrothermal duration. The results show that most HAp nanoparticles were rod-like in shape, exhibiting the most uniform and smallest size (mean diameter and length of 39 nm and 125 nm, respectively) at optimal conditions of 0.64 g CTAB and hydrothermal duration of 12 h. Moreover, good biomineralization capability of the HAp nanorods was confirmed through in vitro tests in simulated body fluid. A bone-like mineral layer of synthesized HAp nanorods formed rapidly after 7 days. This study shows that highly bioactive HAp nanorods can be easily prepared by the hydrothermal method, being a potential nanomaterial for bone regeneration.

  12. Hydrothermal Synthesis and Characterization of 3R Polytypes of Mg-Al Layered Double Hydroxides

    NARCIS (Netherlands)

    Budhysutanto, W.N.

    2010-01-01

    Layered Double Hydroxides (LDH) is a unique group of clays that have an anionic exchange capability. This research explored the hydrothermal method as an alternative method to synthesize Mg-Al LDH. It is a simple and more environmentally friendly compared to the conventional method of co-precipitati

  13. Synthesis and electrochemical properties of Co3O4 nanoparticles by hydrothermal method at different temperatures

    Science.gov (United States)

    Duan, Qiuyan; Chen, Haiyan

    2017-06-01

    In this work, Co3O4 nanoparticles were synthesized by hydrothermal method at different temperatures. The synthesized Co3O4 nanoparticles were characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectrometer (XPS) and nitrogen adsorption-desorption. The Co3O4 nanoparticles prepared at the hydrothermal temperature of 140 °C and at the annealing temperature of 350 °C have a shorter crystal spacing distance associated to the (220) crystal planes, larger BET surface area and more bivalent cobalt on the surface than these of Co3O4 nanoparticles prepared at higher hydrothermal temperature or higher annealing temperature. The supercapacitor performances of synthesized Co3O4 nanoparticles were analysed by cyclic voltammograms (CVs), Galvano static charge/discharge (GCD) and the electrochemical impedance spectroscopy (EIS) in 6 M KOH aqueous electrolyte solution. The Co3O4 nanoparticles produced at lower temperatures exhibit good pseudo capacitance behaviour. Also, owning to the low hydrothermal temperature and the annealing temperature of Co3O4 nanoparticles, they can be relatively low cost in favour of a promising candidate for electrochemical supercapacitors.

  14. Location of Framework Al Atoms in the Channels of ZSM-5: Effect of the (Hydrothermal) Synthesis.

    Science.gov (United States)

    Pashkova, Veronika; Sklenak, Stepan; Klein, Petr; Urbanova, Martina; Dědeček, Jiří

    2016-03-14

    (27) Al 3Q MAS NMR and UV/Vis spectroscopy with bare Co(II) ions as probes of Al pairs in the zeolite framework were employed to analyze the location of framework Al atoms in the channel system of zeolite ZSM-5. Furthermore, the effect of Na(+) ions together with tetrapropylammonium cation (TPA(+)) in the ZSM-5 synthesis gel on the location of Al in the channel system was investigated. Zeolites prepared using exclusively TPA(+) as a structure-directing agent (i.e., in the absence of Na(+) ions) led to 55-90% of Al atoms located at the channel intersection, regardless the presence or absence of Al pairs [Al-O-(Si-O)2 -Al sequences in one ring] in the zeolite framework. The presence of Na(+) ions in the synthesis gel did not modify the Al location at the channel intersection (55-95% of Al atoms) and led only to changes in i) the distribution of framework Al atoms between Al pairs (decrease) and single isolated Al atoms (increase), and ii) the siting of Al in distinguishable framework tetrahedral sites. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Complexing and hydrothermal ore deposition

    CERN Document Server

    Helgeson, Harold C

    1964-01-01

    Complexing and Hydrothermal Ore Deposition provides a synthesis of fact, theory, and interpretative speculation on hydrothermal ore-forming solutions. This book summarizes information and theory of the internal chemistry of aqueous electrolyte solutions accumulated in previous years. The scope of the discussion is limited to those aspects of particular interest to the geologist working on the problem of hydrothermal ore genesis. Wherever feasible, fundamental principles are reviewed. Portions of this text are devoted to calculations of specific hydrothermal equilibriums in multicompone

  16. SYNTHESIS OF ZEOLITE SOCONY MOBIL FROM BLUE SILICA GEL AND RICE HUSK ASH AS CATALYSTS FOR HYDROTHERMAL LIQUEFACTION

    Directory of Open Access Journals (Sweden)

    SUYITNO

    2015-08-01

    Full Text Available Renewable biofuels produced by the hydrothermal liquefaction of rice husks have received much attention because of rapid increases in fuel consumption and corresponding declines in fossil fuel resources. To increase biofuel yields, template-free syntheses of Zeolite Socony Mobil (ZSM catalysts based on blue silica gel and rice husk ash as silica sources were studied. After ZSM synthesis in a closed reactor at 170°C, the crystallinity and crystalline diameters of the products were determined by X-ray diffraction, affording values of 56.33%– 65.81% and 64.3–68.5 nm, respectively. The hydrothermal liquefaction of rice husks with or without a catalyst was conducted in a closed reactor (1200 mm length × 100 mm diameter at 275°C for 45 min. The light biofuel was separated from the ethanol solvent and heavy biofuel via vacuum evaporation. The ZSM catalysts increased the biofuel yields by 2.9%–6.0%. The light biofuels exhibited heating values, flash points, and viscosities of approximately 4.2–4.3 kcal·g−1, 19°C, and 1.48–1.52 cSt, respectively. However, further studies are required to enhance the activity of the ZSMs and increase the quality of the biofuels.

  17. Hydrothermal synthesis of urchin-like MnO{sub 2} nanostructures and its electrochemical character for supercapacitor

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Shuoqing, E-mail: 18780107501@163.com [College of Materials Science and Engineering, Chongqing University, Chongqing 400030 (China); National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400030 (China); Liu, Tianmo, E-mail: tmliu@cqu.edu.cn [College of Materials Science and Engineering, Chongqing University, Chongqing 400030 (China); National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400030 (China); Shi, Dongfeng; Zhang, Yu; Zeng, Wen; Li, Tianming; Miao, Bin [College of Materials Science and Engineering, Chongqing University, Chongqing 400030 (China); National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400030 (China)

    2015-10-01

    Highlights: • Urchin-like α-MnO{sub 2} nanostructures were synthesized via a hydrothermal process. • The possible formation mechanism of the urchin-like α-MnO{sub 2} was discussed. • The evolution of the urchin-like nanostructures due to the increase of reaction temperature. • The urchin-like α-MnO{sub 2} exhibits high specific capacitance of 151.5 F g{sup −1}. • The urchin-like α-MnO{sub 2} shows 93.4% capacitance retention after 1000 cycles. - Abstract: Urchin-like α-MnO{sub 2} nanostructures were successfully synthesized via a simple hydrothermal process at different synthesis temperatures without using any template or surfactant. The microstructure and morphology of as-synthesized products were systematically investigated by focused ion beam, transmission electron microscopy, and high-resolution transmission electron microscopy. The electrochemical test of the prepared MnO{sub 2} exhibits ideal cyclic voltammetry behavior, high specific capacitance (151.5 F g{sup −1} at a current density of 1 A g{sup −1}) and excellent cycling stability (93.4% capacitance retention after 1000 cycles) which suggests its promising application as supercapacitor.

  18. Two-Step Hydrothermal Synthesis of Bifunctional Hematite-Silver Heterodimer Nanoparticles for Potential Antibacterial and Anticancer Applications

    Science.gov (United States)

    Trang, Vu Thi; Tam, Le Thi; Phan, Vu Ngoc; Van Quy, Nguyen; Huy, Tran Quang; Le, Anh-Tuan

    2017-01-01

    In recent years, the development of composite nanostructures containing noble metal and magnetic nanocrystals has attracted much interest because they offer a promising avenue for multifunctional applications in nanomedicine and pharmacotherapy. In this work, we present a facile two-step hydrothermal approach for the synthesis of bifunctional heterodimer nanoparticles (HDNPs) composed of hematite nanocubes (α-Fe2O3 NCs) and silver nanoparticles (Ag-NPs). The formation and magnetic property of α-Fe2O3-Ag HDNPs was analyzed by transmission electron microscopy, x-ray diffraction and vibrating sample magnetometer. Interestingly, the hydrothermal-synthesized α-Fe2O3-Ag HDNPs were found to display significant antibacterial activity against three types of infectious bacteria. The cytotoxicity of α-Fe2O3-Ag nanocomposite against lung cancer A549 cell line was investigated and compared with that of pure α-Fe2O3 NCs and Ag-NPs. The obtained results reveal that the α-Fe2O3-Ag nanocomposite exhibited higher anticancer performance than that of pure Ag-NPs, whereas pure α-Fe2O3 NCs were not cytotoxic to the tested cells. The inhibitory concentration (IC50) of the α-Fe2O3-Ag nanocomposite was found at 20.94 μg/mL. With the aforementioned properties, α-Fe2O3-Ag HDNPs showed a high potential as a multifunctional material for advanced biomedicine and nanotherapy applications.

  19. Two-Step Hydrothermal Synthesis of Bifunctional Hematite-Silver Heterodimer Nanoparticles for Potential Antibacterial and Anticancer Applications

    Science.gov (United States)

    Trang, Vu Thi; Tam, Le Thi; Phan, Vu Ngoc; Van Quy, Nguyen; Huy, Tran Quang; Le, Anh-Tuan

    2017-06-01

    In recent years, the development of composite nanostructures containing noble metal and magnetic nanocrystals has attracted much interest because they offer a promising avenue for multifunctional applications in nanomedicine and pharmacotherapy. In this work, we present a facile two-step hydrothermal approach for the synthesis of bifunctional heterodimer nanoparticles (HDNPs) composed of hematite nanocubes (α-Fe2O3 NCs) and silver nanoparticles (Ag-NPs). The formation and magnetic property of α-Fe2O3-Ag HDNPs was analyzed by transmission electron microscopy, x-ray diffraction and vibrating sample magnetometer. Interestingly, the hydrothermal-synthesized α-Fe2O3-Ag HDNPs were found to display significant antibacterial activity against three types of infectious bacteria. The cytotoxicity of α-Fe2O3-Ag nanocomposite against lung cancer A549 cell line was investigated and compared with that of pure α-Fe2O3 NCs and Ag-NPs. The obtained results reveal that the α-Fe2O3-Ag nanocomposite exhibited higher anticancer performance than that of pure Ag-NPs, whereas pure α-Fe2O3 NCs were not cytotoxic to the tested cells. The inhibitory concentration (IC50) of the α-Fe2O3-Ag nanocomposite was found at 20.94 μg/mL. With the aforementioned properties, α-Fe2O3-Ag HDNPs showed a high potential as a multifunctional material for advanced biomedicine and nanotherapy applications.

  20. Template-less surfactant-free hydrothermal synthesis NiO nanoflowers and their photoelectrochemical hydrogen production

    KAUST Repository

    Qurashi, Ahsanulhaq

    2015-12-01

    A facile direct surfactant-free template-less hydrothermal method is employed for the growth of high surface-area NiO nanoflowers made up of complex and assembled nanosheets network.Field emission scanning electron microscopy revealed that each nanosheet is about 50-60nm thick. Detailed structural analysis reveals single-crystalline nature of NiO nanoflowers with cubic crystal structure. The optical absorption bands in the wavelength range of 350-800nm illustrated in terms of ligand field theory. The photoelectrochemical (PEC), water splitting performance on the NiO nanoflowers were also investigated. © 2015 Hydrogen Energy Publications, LLC.

  1. Resistivity structure of the Furnas hydrothermal system (Azores archipelago, Portugal) from AMT and ERT imaging.

    Science.gov (United States)

    Byrdina, Svetlana; Vandemeulebrouck, Jean; Rath, Volker; Silva, Catarina; Hogg, Colin; Kiyan, Duygu; Viveiros, Fatima; Eleuterio, Joana; Gresse, Marceau

    2016-04-01

    The Furnas volcanic complex is located in the eastern part of the São Miguel Island and comprises a 5 km × 8 km summit depression filled by two nested calderas with several craters and a lake. Present-day volcanic activity of Furnas volcano is mostly located in the northern part of the caldera, within the Furnas village and north to Furnas Lake, where hydrothermal manifestations are mainly fumarolic fields, steam vents, thermal springs, and intense soil diffuse degassing. Considering the Furnas volcano as a whole, the total integrated CO2 efflux is extremely high, with a total amount of CO2 close to 1000 ton per day (Viveiros et al., 2009). We present the first results of an electrical resistivity tomography (ERT), combined with audio-magneto-telluric (AMT) measurements aligned along two profiles inside the caldera. The purpose of this survey is to delimit the extent, the geometry, and the depth of the hydrothermal system and to correlate the deep resistivity structure with high resolution cartography of diffuse CO2 flux (Viveiros et al, 2015). The ERT and AMT methods are complementary in terms of resolution and penetration depth: ERT can image the structural details of shallow hydrothermal system (down to 100 m in our study) while AMT can image at lower resolution deeper structures at the roots of a volcano (down to 4 km in our study). Our first independent 2D inversions of the ERT-AMT data show a good agreement between the surficial and deeper features. Below the main fumarole area we observe a low resistivity body (less than 1 Ohmm) which corresponds well to the high CO2 flux at the surface and is associated with an extended conductive body at larger depth. These results strongly suggest the presence of hydrothermal waters at depth or/and the presence of altered clay-rich material. On a larger scale however, the geometry of the conducting zones differs slightly from what was expected from earlier surface studies, and may not be directly related to fault zones

  2. Hydrothermal synthesis of a novel BiErWO{sub 6} photocatalyst with wide spectral responsive property

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhijie, E-mail: zjzhang@sit.edu.cn [Department of Materials Science and Engineering, Shanghai Institute of Technology, 100 Haiquan Road, Shanghai 201418 (China); Wang, Wenzhong [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China); Zhou, Yu [Department of Materials Science and Engineering, Shanghai Institute of Technology, 100 Haiquan Road, Shanghai 201418 (China)

    2014-11-15

    Highlights: • A novel BiErWO{sub 6} photocatalyst was synthesized by a hydrothermal method. • The BiErWO{sub 6} showed good photocatalytic performance under simulated solar light. • The BiErWO{sub 6} also exhibited high photo-activity under a green LED irradiation. - Abstract: To overcome the drawback of low solar energy utilization rate brought by general photocatalysts, a novel BiErWO{sub 6} photocatalyst with wide spectral responsive property was designed and synthesized by a hydrothermal method. The effects of hydrothermal temperature on the phase structure and the photocatalytic activities of the products were investigated. Due to the wide spectral absorption range, the as-prepared BiErWO{sub 6} photocatalyst showed good photocatalytic performance in degradation of rhodamine B (RhB) under simulated solar light. Moreover, the BiErWO{sub 6} photocatalyst also exhibited high photocatalytic activity under a green LED (λ = 520 nm) irradiation. This work provided a new concept for rational design and development of high-performance photocatalysts.

  3. Facile morphology-controlled hydrothermal synthesis of flower-like self-organized ZnO architectures

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Rongxian; Zhang, Qi [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China); Yang, Xiaofei; Zhang, Du; Qin, Jieling; Lu, Chunyu; Ding, Heyi; Yan, Xuehua; Tang, Hua; Wang, Mingsong [School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China)

    2011-11-15

    Flower-like self-organized crystalline ZnO architectures were obtained through a facile and controlled hydrothermal process. As-synthesized products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), electron diffraction and UV-Vis spectroscopy. XRD and electron diffraction results confirmed the obtained materials are pure wurtzite ZnO. The effects of different ratios of starting materials and solvent on the morphologies of ZnO hydrothermal products were also evaluated by SEM observations. It is suggested that the use of water, rather than ethanol as the solvent, as well as employing a precursor of Zn(Ac){sub 2} and 2NaOH (v/v) in hydrothermal reactions are responsible for the generation of specific flower-like self-assembled ZnO structures. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. Direct Energy Supply to the Reaction Mixture during Microwave-Assisted Hydrothermal and Combustion Synthesis of Inorganic Materials

    Directory of Open Access Journals (Sweden)

    Roberto Rosa

    2014-05-01

    Full Text Available The use of microwaves to perform inorganic synthesis allows the direct transfer of electromagnetic energy inside the reaction mixture, independently of the temperature manifested therein. The conversion of microwave (MW radiation into heat is useful in overcoming the activation energy barriers associated with chemical transformations, but the use of microwaves can be further extended to higher temperatures, thus creating unusual high-energy environments. In devising synthetic methodologies to engineered nanomaterials, hydrothermal synthesis and solution combustion synthesis can be used as reference systems to illustrate effects related to microwave irradiation. In the first case, energy is transferred to the entire reaction volume, causing a homogeneous temperature rise within a closed vessel in a few minutes, hence assuring uniform crystal growth at the nanometer scale. In the second case, strong exothermic combustion syntheses can benefit from the application of microwaves to convey energy to the reaction not only during the ignition step, but also while it is occurring and even after its completion. In both approaches, however, the direct interaction of microwaves with the reaction mixture can lead to practically gradient-less heating profiles, on the basis of which the main observed characteristics and properties of the aforementioned reactions and products can be explained.

  5. Properties of ceria doped with gadolinia via microwave-assisted hydrothermal synthesis; Propriedades de ceria dopada com gadolinia via sintese hidrotermal assistida por micro-ondas

    Energy Technology Data Exchange (ETDEWEB)

    Carregosa, J.D.C.; Oliveira, R.M.P.B. [Universidade Federal de Sergipe (UFS), Sao Cristovao, SE (Brazil); Macedo, D.A. [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil); Nascimento, R.M., E-mail: jdcovello@hotmail.com [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

    2016-07-01

    The solid solution of CeO{sub 2} doped with Gd{sup 3+} (CGO) is a promising candidate for electrolyte in Solid Oxide Full Cells (SOFCs) operating in intermediate and low temperatures. The reduction of the working temperature of these energy conversion devices is the great technological challenge to its marketing. In this work, nanocrystalline powders of Ce{sub 1-x}Gd{sub x}O{sub 2-x/2} with x=0, x=0.1 e x=0.2 were obtained via microwave-hydrothermal synthesis at low temperature and times of synthesis (10 and 20 min at 120° C). The powders were analyzed by TG-DTA, DRX and dilatometry. The results showed characteristic peaks of the cubic fluorite-type structure, referring to the cerium oxide (CeO{sub 2}), without the presence of secondary peaks. It was also observed that the samples processed at levels of 10 and 20 minutes showed distinct behaviors in contrast to the concentrations of Gd{sup 3+}. (author)

  6. Facile one-step hydrothermal synthesis and luminescence properties of Eu{sup 3+}-doped NaGd(WO{sub 4}){sub 2} nanophosphors

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Zehan; Cai, Peiqing; Chen, Cuili; Pu, Xipeng; Kim, Sun Il, E-mail: sikim@pknu.ac.kr; Jin Seo, Hyo, E-mail: hjseo@pknu.ac.kr

    2017-06-01

    Eu{sup 3+}-doped NaGd(WO{sub 4}){sub 2} nanophosphors were synthesized via a facile one-step hydrothermal method without any surfactants or a further heat treatment. X-ray powder diffraction (XRD), scanning electron microscope (SEM), fourier transform infrared spectroscopy (FT-IR), the photoluminescence (PL) excitation and emission spectra, and decay curves were used to characterize NaGd(WO{sub 4}){sub 2}:Eu{sup 3+} phosphors. The results show that the Eu{sup 3+}-concentration has little influence on the structure and morphology of the as-synthesized samples. However, pH value plays a vital role on the structure and morphology of NaGd(WO{sub 4}){sub 2}. The well-crystallized sheet-like NaGd(WO{sub 4}){sub 2} phosphors can be obtained only at pH = 5–7. On the basis of the time-dependent synthesis, a possible growth mechanism of sheet-like architectures is proposed. The luminescence properties of NaGd{sub 1-x}Eu{sub x}(WO{sub 4}){sub 2} (0 ≤ x ≤ 1) are investigated. It is found that the charge transfer band of Eu{sup 3+} shifts to lower energy and broadens with increasing the Eu{sup 3+}-concentration. - Highlights: • NaGd(WO{sub 4}){sub 2}:Eu{sup 3+} nanosheets were synthesized by facile one-step hydrothermal method. • Luminescence properties of NaGd(WO{sub 4}){sub 2}:Eu{sup 3+} phosphor were firstly reported. • The CT band of Eu{sup 3+} depends strongly on Eu{sup 3+}-concentrations.

  7. Synthesis and characterization of hexagonal nano-sized nickel selenide by simple hydrothermal method assisted by CTAB

    Science.gov (United States)

    Sobhani, Azam; Davar, Fatemeh; Salavati-Niasari, Masoud

    2011-07-01

    Nano-sized nickel selenide powders have been successfully synthesized via an improved hydrothermal route based on the reaction between NiCl2·6H2O, SeCl4 and hydrazine (N2H4·H2O) in water, in present of cetyltrimethyl ammonium bromide (CTAB) as surfactant, at various conditions. The products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and X-ray energy dispersive spectroscopy analysis. Effects of temperature, reaction time and reductant agent on the morphology, the particle sizes and the phase of the final products have been investigated. It was found that the phase and morphology of the products could be greatly influenced by these parameters. The synthesis procedure is simple and uses less toxic reagents than the previously reported methods. Photoluminescence (PL) was used to study the optical properties of NiSe samples.

  8. Synthesis and characterization of hexagonal nano-sized nickel selenide by simple hydrothermal method assisted by CTAB

    Energy Technology Data Exchange (ETDEWEB)

    Sobhani, Azam [Department of Inorganic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, P.O. Box 87317-51167 (Iran, Islamic Republic of); Davar, Fatemeh [Institute of Nano Science and Nano Technology, University of Kashan, Kashan, P.O. Box 87317-51167 (Iran, Islamic Republic of); Salavati-Niasari, Masoud, E-mail: salavati@kashanu.ac.ir [Department of Inorganic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, P.O. Box 87317-51167 (Iran, Islamic Republic of); Institute of Nano Science and Nano Technology, University of Kashan, Kashan, P.O. Box 87317-51167 (Iran, Islamic Republic of)

    2011-07-01

    Nano-sized nickel selenide powders have been successfully synthesized via an improved hydrothermal route based on the reaction between NiCl{sub 2}.6H{sub 2}O, SeCl{sub 4} and hydrazine (N{sub 2}H{sub 4}.H{sub 2}O) in water, in present of cetyltrimethyl ammonium bromide (CTAB) as surfactant, at various conditions. The products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and X-ray energy dispersive spectroscopy analysis. Effects of temperature, reaction time and reductant agent on the morphology, the particle sizes and the phase of the final products have been investigated. It was found that the phase and morphology of the products could be greatly influenced by these parameters. The synthesis procedure is simple and uses less toxic reagents than the previously reported methods. Photoluminescence (PL) was used to study the optical properties of NiSe samples.

  9. Green synthesis of silver nanoparticles in aloe vera plant extract prepared by a hydrothermal method and their synergistic antibacterial activity

    Science.gov (United States)

    Phromviyo, Nutthakritta; Boueroy, Parichart; Chompoosor, Apiwat

    2016-01-01

    Background There is worldwide interest in silver nanoparticles (AgNPs) synthesized by various chemical reactions for use in applications exploiting their antibacterial activity, even though these processes exhibit a broad range of toxicity in vertebrates and invertebrates alike. To avoid the chemical toxicity, biosynthesis (green synthesis) of metal nanoparticles is proposed as a cost-effective and environmental friendly alternative. Aloe vera leaf extract is a medicinal agent with multiple properties including an antibacterial effect. Moreover the constituents of aloe vera leaves include lignin, hemicellulose, and pectins which can be used in the reduction of silver ions to produce as AgNPs@aloe vera (AgNPs@AV) with antibacterial activity. Methods AgNPs were prepared by an eco-friendly hydrothermal method using an aloe vera plant extract solution as both a reducing and stabilizing agent. AgNPs@AV were characterized using XRD and SEM. Additionally, an agar well diffusion method was used to screen for antimicrobial activity. MIC and MBC were used to correlate the concentration of AgNPs@AV its bactericidal effect. SEM was used to investigate bacterial inactivation. Then the toxicity with human cells was investigated using an MTT assay. Results The synthesized AgNPs were crystalline with sizes of 70.70 ± 22-192.02 ± 53 nm as revealed using XRD and SEM. The sizes of AgNPs can be varied through alteration of times and temperatures used in their synthesis. These AgNPs were investigated for potential use as an antibacterial agent to inhibit pathogenic bacteria. Their antibacterial activity was tested on S. epidermidis and P. aeruginosa. The results showed that AgNPs had a high antibacterial which depended on their synthesis conditions, particularly when processed at 100 oC for 6 h and 200 oC for 12 h. The cytotoxicity of AgNPs was determined using human PBMCs revealing no obvious cytotoxicity. These results indicated that AgNPs@AV can be effectively utilized in

  10. Green synthesis of silver nanoparticles in aloe vera plant extract prepared by a hydrothermal method and their synergistic antibacterial activity

    Directory of Open Access Journals (Sweden)

    Patcharaporn Tippayawat

    2016-10-01

    Full Text Available Background There is worldwide interest in silver nanoparticles (AgNPs synthesized by various chemical reactions for use in applications exploiting their antibacterial activity, even though these processes exhibit a broad range of toxicity in vertebrates and invertebrates alike. To avoid the chemical toxicity, biosynthesis (green synthesis of metal nanoparticles is proposed as a cost-effective and environmental friendly alternative. Aloe vera leaf extract is a medicinal agent with multiple properties including an antibacterial effect. Moreover the constituents of aloe vera leaves include lignin, hemicellulose, and pectins which can be used in the reduction of silver ions to produce as AgNPs@aloe vera (AgNPs@AV with antibacterial activity. Methods AgNPs were prepared by an eco-friendly hydrothermal method using an aloe vera plant extract solution as both a reducing and stabilizing agent. AgNPs@AV were characterized using XRD and SEM. Additionally, an agar well diffusion method was used to screen for antimicrobial activity. MIC and MBC were used to correlate the concentration of AgNPs@AV its bactericidal effect. SEM was used to investigate bacterial inactivation. Then the toxicity with human cells was investigated using an MTT assay. Results The synthesized AgNPs were crystalline with sizes of 70.70 ± 22-192.02 ± 53 nm as revealed using XRD and SEM. The sizes of AgNPs can be varied through alteration of times and temperatures used in their synthesis. These AgNPs were investigated for potential use as an antibacterial agent to inhibit pathogenic bacteria. Their antibacterial activity was tested on S. epidermidis and P. aeruginosa. The results showed that AgNPs had a high antibacterial which depended on their synthesis conditions, particularly when processed at 100 oC for 6 h and 200 oC for 12 h. The cytotoxicity of AgNPs was determined using human PBMCs revealing no obvious cytotoxicity. These results indicated that AgNPs@AV can be effectively

  11. Controllable Synthesis of Single-Crystalline CdO and Cd(OH2Nanowires by a Simple Hydrothermal Approach

    Directory of Open Access Journals (Sweden)

    Au Chaktong

    2010-01-01

    Full Text Available Abstract Single-crystalline Cd(OH2 or CdO nanowires can be selectively synthesized at 150 °C by a simple hydrothermal method using aqueous Cd(NO32 as precursor. The method is biosafe, and compared to the conventional oil-water surfactant approach, more environmental-benign. As revealed by the XRD results, CdO or Cd(OH2 nanowires can be generated in high purity by varying the time of synthesis. The results of FESEM and HRTEM analysis show that the CdO nanowires are formed in bundles. Over the CdO-nanowire bundles, photoluminescence at ~517 nm attributable to near band-edge emission of CdO was recorded. Based on the experimental results, a possible growth mechanism of the products is proposed.

  12. Green synthesis of silver nanoparticles in aloe vera plant extract prepared by a hydrothermal method and their synergistic antibacterial activity.

    Science.gov (United States)

    Tippayawat, Patcharaporn; Phromviyo, Nutthakritta; Boueroy, Parichart; Chompoosor, Apiwat

    2016-01-01

    There is worldwide interest in silver nanoparticles (AgNPs) synthesized by various chemical reactions for use in applications exploiting their antibacterial activity, even though these processes exhibit a broad range of toxicity in vertebrates and invertebrates alike. To avoid the chemical toxicity, biosynthesis (green synthesis) of metal nanoparticles is proposed as a cost-effective and environmental friendly alternative. Aloe vera leaf extract is a medicinal agent with multiple properties including an antibacterial effect. Moreover the constituents of aloe vera leaves include lignin, hemicellulose, and pectins which can be used in the reduction of silver ions to produce as AgNPs@aloe vera (AgNPs@AV) with antibacterial activity. AgNPs were prepared by an eco-friendly hydrothermal method using an aloe vera plant extract solution as both a reducing and stabilizing agent. AgNPs@AV were characterized using XRD and SEM. Additionally, an agar well diffusion method was used to screen for antimicrobial activity. MIC and MBC were used to correlate the concentration of AgNPs@AV its bactericidal effect. SEM was used to investigate bacterial inactivation. Then the toxicity with human cells was investigated using an MTT assay. The synthesized AgNPs were crystalline with sizes of 70.70 ± 22-192.02 ± 53 nm as revealed using XRD and SEM. The sizes of AgNPs can be varied through alteration of times and temperatures used in their synthesis. These AgNPs were investigated for potential use as an antibacterial agent to inhibit pathogenic bacteria. Their antibacterial activity was tested on S. epidermidis and P. aeruginosa. The results showed that AgNPs had a high antibacterial which depended on their synthesis conditions, particularly when processed at 100 (o)C for 6 h and 200 (o)C for 12 h. The cytotoxicity of AgNPs was determined using human PBMCs revealing no obvious cytotoxicity. These results indicated that AgNPs@AV can be effectively utilized in pharmaceutical

  13. Formation Mechanism and Template-free Synthesis of Hierarchical m-ZrO2 Nanorods by Hydrothermal Method

    Institute of Scientific and Technical Information of China (English)

    Shahzad Ahmad KHAN; FU Zhengyi; Muhammad ASIF; WANG Weimin; WANG Hao

    2015-01-01

    Here, a new idea was proposed for template-free synthesis of hierarchical m-ZrO2 nanorods and “their” possible formation mechanism based on a series of chemical reactions by simple hydrothermal method. The traditional preparation methods of hierarchical ZrO2 nanorods involved inexpensive equipment, complicated process, and high production cost. The as-synthesized products composed of many nanorods with 180-200 nm in diameter and 5-7μm in length. The ifnal product after annealing involved hierarchical monoclinic ZrO2 (m-ZrO2) nanorods, namely, the big nanorod was made up of many small nanorods with 40-50 nm in diameter and 500-600 nm in length. The experimental results were useful in understanding the chemical properties of ZrB2 and ZrO2 and the design of the derivatives for m-ZrO2 nanomaterials.

  14. Hydrothermal Synthesis and Visible-light Photocatalytic Activities of SnS2 Nanoflakes

    Institute of Scientific and Technical Information of China (English)

    JIA Tiekun; MIN Zhiyu; CAO Jianliang; SUN Guang; WANG Xiaodong; ZHANG Zhanying; LI Tingting

    2015-01-01

    SnS2 nanoflakes were successfully synthesized via a simple hydrothermal process. The as-prepared SnS2 samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen adsorption-desorption isotherms, and UV-vis diffuse reflectance spectroscopy (DRS). The photocatalytic activities of the as-prepared SnS2 nanoflakes under visible light irradiation (λ>420 nm) were evaluated by the degradation of rhodamine B (RhB). The effect of hydrothermal temperatures on the photocatalytic efficiency of as-prepared SnS2 nanoflakes was investigated. The experimental result showed that SnS2 nanoflakes synthesized at the temprature of 160o had higher photocatalytic efficiency and good photocatalytic stability.

  15. Hydrothermal synthesis of nanostructured titania; Sintese hidrotermica de ceramicas de titania nanoestruturada

    Energy Technology Data Exchange (ETDEWEB)

    Yoshito, W.K.; Ferreira, N.A.M.; Lazar, D.R.R.; Ussui, V., E-mail: wkyoshito@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Rumbao, A.C.S. [Universidade Presbiteriana Mackenzie (UPM), Sao Paulo, SP (Brazil)

    2011-07-01

    Titania ceramics have many applications due to its surface properties and, recently, its nanostructured compounds, prepared by hydrothermal treatments, have been described to improve these properties. In this work, commercial titanium dioxide was treated with 10% sodium hydroxide solution in a pressurized reactor at 150 deg C for 24 hours under vigorous stirring and then washed following two different procedures. The first one consisted of washing with water and ethanol and the second with water and hydrochloric acid solution (1%). Resulting powders were characterized by X-ray diffraction, N{sub 2} gas adsorption and field emission gun scanning and transmission electronic microscopy. Results showed that from an original starting material with mainly rutile phase, both anatase and H{sub 2}Ti{sub 3}O{sub 7} phase could be identified after the hydrothermal treatment. Surface area of powders presented a notable increase of one order of magnitude and micrographs showed a rearrangement on the microstructure of powders. (author)

  16. Hydrothermal Synthesis of SBA-15 Using Sodium Silicate Derived from Coal Gangue

    Directory of Open Access Journals (Sweden)

    Jing Wang

    2013-01-01

    Full Text Available Well-ordered SBA-15 was prepared with a hydrothermal route by sodium silicate derived from coal gangue. The as-prepared sample was analyzed by SAXRD, BET, TEM, and SEM, respectively. The results indicate that at a low hydrothermal temperature of 100∘C the well-ordered mesoporous SBA-15 could be synthesized. The surface area, pore volume, and pore size of the sample are 552 m2/g, 0.54 cm3/g, and 7.0 nm, respectively. It is suggested that coal gangue could be used in obtaining an Si source to prepare mesoporous materials, such as SBA-15.

  17. One step microwaved-assisted hydrothermal synthesis of nitrogen doped graphene for high performance of supercapacitor

    Science.gov (United States)

    Sari, Fitri Nur Indah; Ting, Jyh-Ming

    2015-11-01

    Nitrogen doped graphene (NDG) has been synthesized using a microwave-assisted hydrothermal (MHT) method within only several minute. In the method, homemade graphene oxide was reduced using ethylene glycol (EG) to obtain the graphene while ammonia liquid was used as the nitrogen source. However, it was found that the reduction and doping simultaneously occurred and the addition of ammonia further enhanced the reduction. The reduction and doping were examined through various analysis and the mechanisms were proposed. The effects of the hydrothermal temperature and time on the reduction and doping were discussed. It was also shown that the doping leads to enhanced specific capacitance by as much as 54%, a high specific energy density of 42.8 W h kg-1 at a power density of 4330 W kg-1, and excellent long term stability up to 98% retention after 1000 cycles at wide working voltage of 1.6 V in 2 M H2SO4.

  18. Synthesis of Ordered Cubic Periodic Mesoporous Silica with High Hydrothermal Stability

    Institute of Scientific and Technical Information of China (English)

    LAI Xiao-yong; TU Jin-chun; WANG Hong; DU Jiang; YANG Mei; MAO Dan; XING Chao-jian; WANG Dan; LI Xiao-tian

    2009-01-01

    @@ 1 Introduction Since its first discovery in 1992~[1,2], ordered me-soporous silica material with large pore size, high surface area, and high pore volume has attracted great attention for the potentially wide application in catalysis, adsorption, separation, and ion exchange, etc. However, the poor hydrothermal stability of meso-porous silica has limited its wide application in industry~[3,4].

  19. Petrology of hydrothermal alteration in the Vargeão basaltic impact structure (South Brazil)

    Science.gov (United States)

    Yokoyama, E.; Nédélec, A.; Trindade, R. I.; Baratoux, D.; Berger, G.

    2011-12-01

    Impact cratering process is of primary importance in the evolution of solid bodies of the Solar System. But craters on basaltic rocks, which are the best analog for the surface of other planets and satellites, are rare on Earth. Most studies to date were done in the Lonar crater, a simple crater 1.8 km in diameter, formed on the basaltic flows of the Deccan Province (India). Recently, one medium-size complex crater was identified on volcanic rocks of the Paraná basin (south Brazil) and may provide additional analog to the craters of most rocky planets and satellites. The 12 km wide Vargeão is a very well-preserved impact structure formed on basaltic and subordinately rhyodacites flows of the Serra Geral Formation (about 133-131 Ma), which are locally intertrapped by eolian-sandstones of Botucatu Formation. The impact-related features are represented by shatter cones, breccia-veins and planar deformation features in quartz (few occurrence in the sandstones). This work is focused on the petrogenesis of the centimeter breccia-veins that are found in all lithologies. We conducted a detailed petrological study (petrography, microprobe, SEM, Raman spectroscopy, Spectroscopy of reflectance and XRD) on these veins and their host-rocks. Our results show that the veins were strongly affected by the post-impact hydrothermal fluids. The hydrothermal alteration varies geographically in the structure. On the rim area this alteration consists of total or partial substitution of the melt matrix by quartz, calcite, iron oxides and clay minerals. At the central area, the alteration mineral assembly is composed of quartz, iron oxides, zeolites, clay minerals and rarely calcite. Usually, the alteration shows a zoned setting, which also varies locally. The nature of occurrence of second mineral identified in the context of post-impact hydrothermal alteration of impact craters on basalt represent a critical interpretation to interpret alteration signature of impact craters and the old

  20. Effects of sodium dodecyl benzene sulfonate on the crystal structures and photocatalytic performance of ZnO powders prepared by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Limin; Dong, Shuying; Li, Qilu; Li, Yifan; Pi, Yunqing; Liu, Menglin; Han, Xiao; Sun, Jianhui, E-mail: sunjh@htu.cn

    2015-11-15

    A facile and efficient route for the controllable synthesis of ZnO nanostructures by hydrothermal method using sodium dodecyl benzene sulfonate (SDBS) as surfactant was reported. The obtained products were well characterized with the aid of various techniques to probe their crystallographic, morphological, chemical, electrochemical and optical properties. The prepared products were used as photocatalysts in the application of the degradation of metronidazole (MNZ)-contained wastewater under visible light irradiation. A 4.5-fold augmentation of degradation efficiency was in turn observed for optimal ZnO (ZO-0.75) photocatalyst compared with that of sample without SDBS addition (ZO) under the visible light irradiation. The effects of SDBS dosage on the crystal structures of prepared samples as well as the crystal growth mechanism were also probed. - Graphical abstract: ZnO photocatalysts were fabricated through a facile and efficient hydrothermal method using SDBS as structure-directing surfactant in a controllable manner. In particular, the sample with different SDBS dosage exhibited distinct crystal structure and photocatalytic performance. - Highlights: • A rod-like ZnO photocatalyst was facilely synthesized by using SDBS as surfactant. • The effect of SDBS dosage on the crystal structure of photocatalyst was probed. • The probably crystal growth mechanism of prepared photocatalyst was explored. • The optimal ZnO with 0.75 g SDBS dosage displayed the best photocatalytic activity.

  1. Assessment of structural diversity in combinatorial synthesis.

    Science.gov (United States)

    Fergus, Suzanne; Bender, Andreas; Spring, David R

    2005-06-01

    This article covers the combinatorial synthesis of small molecules with maximal structural diversity to generate a collection of pure compounds that are attractive for lead generation in a phenotypic, high-throughput screening approach. Nature synthesises diverse small molecules, but there are disadvantages with using natural product sources. The efficient chemical synthesis of structural diversity (and complexity) is the aim of diversity-oriented synthesis, and recent progress is reviewed. Specific highlights include a discussion of strategies to obtain structural diversity and an analysis of molecular descriptors used to classify compounds. The assessment of how successful one synthesis is versus another is subjective, therefore we test-drive software to assess structural diversity in combinatorial synthesis, which is freely available via a web interface.

  2. Synthesis of nano-hydroxyapatite under a sonochemical/hydrothermal condition

    Energy Technology Data Exchange (ETDEWEB)

    Manafi, S A; Yazdani, B; Rahimiopour, M R; Sadrnezhaad, S K; Amin, M H; Razavi, M [Ceramic Department, Materials and Energy Research Center, PO Box 14155-4777, Tehran (Iran, Islamic Republic of)], E-mail: rahimi40@yahoo.com

    2008-06-01

    In this study, hydroxyapatite (denoted as HAp) nanostructure with uniform morphologies, controllable size, nano-dispersion and narrow size distribution in diameter has been synthesized successfully by low-temperature hydrothermal process, and the as-synthesized powders were characterized by XRD, scanning electron microscopy, high-resolution transmission microscopy, FT-IR, Zetasizer and inductively coupled plasma. In the present work, a novel sonochemical technique using CaHPO{sub 4}.2H{sub 2}O/NaOH/distilled water with cetyltrimethylammonium bromide ((CH{sub 3}(CH{sub 2}){sub 15}N{sup +}(CH{sub 3}){sub 3}Br{sup -}) designated as CTAB) under a hydrothermal condition to synthesize HAp nanostructure was described. Furthermore, the usage of a high basic condition and a water environment are the two crucial keys in ensuring the formation of HAp in the hydrothermal/sonochemical processes. However, the crystallite size and crystallinity degree of the HAp increased with increasing annealing temperature. Indeed, the present work will introduce a new method in synthesizing HAs for scientific and medical engineering.

  3. Microwave-hydrothermal synthesis of TiO2 and zirconium doped TiO2 adsorbents for removal of As(III) and As(V)

    OpenAIRE

    Ivan Andjelkovic; Dalibor Stankovic; Milica Jovic; Marijana Markovic; Jugoslav Krstic; Dragan Manojlovic; Goran Roglic

    2015-01-01

    Microwave-hydrothermal method was used for the synthesis of TiO2 and TiO2 doped with zirconium. The method was fast and simple and adsorbents were used for removal of As(III) and As(V) from aqueous solutions. The adsorbents were characterized by BET surface area measurements and powder XRD. Experiments showed that TiO2 doped with 10% of Zr using the microwave-hydrothermal method have greater specific surface area and total pore volume in comparison with TiO2 synthesized using the same method....

  4. Effect of hydrothermal pretreatment on the structural changes of alkaline ethanol lignin from wheat straw

    Science.gov (United States)

    Chen, Xue; Li, Hanyin; Sun, Shaoni; Cao, Xuefei; Sun, Runcang

    2016-12-01

    Due to the enormous abundance of lignin and its unique aromatic nature, lignin has great potential for the production of industrially useful fuels, chemicals, and materials. However, the rigid and compact structure of the plant cell walls significantly blocks the separation of lignin. In this study, wheat straw was hydrothermally pretreated at different temperatures (120–200 °C) followed by post-treatment with 70% ethanol containing 1% NaOH to improve the isolation of lignin. Results demonstrated that the content of associated carbohydrates of the lignin fractions was gradually reduced with the increment of the hydrothermal severity. The structure of the lignins changed regularly with the increase of the pretreatment temperature from 120 to 200 °C. In particular, the contents of β-O-4‧, β-β‧, β-5‧ linkages and aliphatic OH in the lignins showed a tendency of decrease, while the content of phenolic OH and thermal stability of the lignin fractions increased steadily as the increment of the pretreatment temperature.

  5. Ultrafast Hydro-Micromechanical Synthesis of Calcium Zincate: Structural and Morphological Characterizations

    Directory of Open Access Journals (Sweden)

    Vincent Caldeira

    2017-01-01

    Full Text Available Calcium zincate is a compound with a large panel of application: mainly known as an advantageous replacement of zinc oxide in negative electrodes for air-zinc or nickel-zinc batteries, it is also used as precursor catalyst in biodiesel synthesis and as antifungal compound for the protection of limestone monuments. However, its synthesis is not optimized yet. In this study, it was elaborated using an ultrafast synthesis protocol: Hydro-Micromechanical Synthesis. Two other synthesis methods, Hydrochemical Synthesis and Hydrothermal Synthesis, were used for comparison. In all cases, the as-synthesized samples were analyzed by X-ray diffraction, scanning electron microscopy, and LASER diffraction particle size analysis. Rietveld method was used to refine various structural parameters and obtain an average crystallite size, on a Hydro-Micromechanical submicronic sample. X-ray single crystal structure determination was performed on a crystal obtained by Hydrochemical Synthesis. It has been shown that regardless of the synthesis protocol, the prepared samples always crystallize in the same crystal lattice, with P21/c space group and only differ from their macroscopic textural parameters. Nevertheless, only the Hydro-Micromechanical method is industrially scalable and enables a precise control of the textural parameters of the obtained calcium zincate.

  6. Hydrothermal synthesis of copper selenides with controllable phases and morphologies from an ionic liquid precursor

    Science.gov (United States)

    Liu, Xiaodi; Duan, Xiaochuan; Peng, Peng; Zheng, Wenjun

    2011-12-01

    Cu2-xSe nanocrystals and CuSe nanoflakes are successfully synthesized through a convenient hydrothermal method from an ionic liquid precursor 1-n-butyl-3-ethylimidazolium methylselenite ([BMIm][SeO2(OCH3)]). The phases and morphologies of the copper selenides can be controlled by simply changing the atom ratio of Cu/Se in the reactants and reaction temperature. Furthermore, it is found that the [BMIm][SeO2(OCH3)] not only serves as Se source but also has influence on the shapes of CuSe nanoflakes. The adsorption of alkyl imidazolium rings ([BMIm]+) onto the (0001) facets of covellite CuSe prohibits the growth in the [0001] direction, and CuSe nuclei growth mainly processes along the six symmetric directions (+/-[01&cmb.macr;11], +/-[101&cmb.macr;1&cmb.macr;], and +/-[1&cmb.macr;100]) to form flakelike CuSe. The obtained copper selenides are characterized by XRD, SEM, EDS, XPS, TEM, and HRTEM. The results indicate that the Cu2-xSe nanocrystals are nearly spherical particles with an average diameter of about 20 nm, the hexagonal CuSe nanoflakes are single crystals with an edge length of 100-400 nm and a thickness of 25-50 nm. The potential formation mechanism of the copper selenides is also proposed.Cu2-xSe nanocrystals and CuSe nanoflakes are successfully synthesized through a convenient hydrothermal method from an ionic liquid precursor 1-n-butyl-3-ethylimidazolium methylselenite ([BMIm][SeO2(OCH3)]). The phases and morphologies of the copper selenides can be controlled by simply changing the atom ratio of Cu/Se in the reactants and reaction temperature. Furthermore, it is found that the [BMIm][SeO2(OCH3)] not only serves as Se source but also has influence on the shapes of CuSe nanoflakes. The adsorption of alkyl imidazolium rings ([BMIm]+) onto the (0001) facets of covellite CuSe prohibits the growth in the [0001] direction, and CuSe nuclei growth mainly processes along the six symmetric directions (+/-[01&cmb.macr;11], +/-[101&cmb.macr;1&cmb.macr;], and +/-[1

  7. Hydrothermal Synthesis and Crystal Structure of A Zinc Complex with Phthalic Acid and Medpq Ligands%由邻苯二甲酸和Medpq配体构筑的锌的配合物的水热合成及晶体测定

    Institute of Scientific and Technical Information of China (English)

    崔运成; 黄艳菊; 杜刚

    2009-01-01

    A metal-organic coordination polymer[Zn(Pht)(Medpq)]n(Pht=phthalic acid,Medpq=2-methyldipyrido [3,2-f:2',3'-h]quinoxaline)(1)has been hydrothermally synthesized and structurally characterized by elemental analysis,IR spectrum,TG and X-ray single-crystal structure analysis.Title complex crystallizes in the monoclinic system,space group Cc,with a=1.0274(4)nm,b=2.955 7(11)nm,c=0.685 2(3)nm,β=112.941°,V=1.916 3(13)nm3,C23H14N4O4Zn,Mr=475.75,Dc=1.649g·cm3,μ(Mo Kα)=1.324mm-1,F(000)=968,Z=4,the final R=0.0388 and wR=0.071 7 for 2 697 observed reflections(I>2δ(I)).In the crystal structure,the Zinc atom is six-coordinated with four carboxylate oxygen atoms from two different carboxylate groups and two nitrogen atoms from Medpq ligand, showing a slightly distorted octahedral geometry.Furthermore,it exhibits a one-dimensional structure with Pht-Zn-Medpq as building units.CCDC:716600.

  8. Permeability Structure Beneath the Lost City Hydrothermal Field, Atlantis Massif Oceanic Core Complex

    Science.gov (United States)

    McCaig, A. M.; Titarenko, S.

    2012-12-01

    The Lost City Hydrothermal Field (LCHF) has been venting low temperature (50-90 °C) alkaline fluids for at least 120,000 years. It is located close to the crest of the transform wall of the Atlantis Massif (30 °N, MAR), and is underlain by detachment fault schists and serpentinized peridotites with minor gabbro. Only 5km to the north, IODP Hole 1309D sampled 1400 m of gabbroic rocks. An almost linear thermal gradient of ~100 °C/km has recently been measured in the Hole during IODP expedition 340T, a unique piece of data in young ocean crust. The combination of a steep conductive gradient in proximity to a long lived hydrothermal system places severe constraints on the permeability structure of the Massif. We have used Comsol Multiphysics to create the first 2-D topographic model of the LCHF using a N-S profile through the vent site and Hole 1309D. Initial models use a constant basal heat flow (0.2 W/m2) which produces a steady state conductive gradient of about 85 °C/km using temperature-dependent conductivity and heat capacity. We include a low permeability basal layer and in some models a lower permeability zone beneath the IODP Hole with a boundary dipping steeply southwards, corresponding to a boundary between gabbro and serpentinite inferred from seismic tomography. We have used two top boundary conditions; (1) a mixed boundary condition in which dT/dz =0 if flow is upwards, and T=0 if flow is downwards, and (2) T=0. The first boundary condition is normally used in hydrothermal modelling but produces serious vent temperature artifacts at low upward flow rates since heat cannot escape conductively. The second boundary condition produces more stable models and has been shown by Wilcock (1998) to reproduce the form of hydrothermal circulation accurately. However vent temperatures can only be approximated due to the upper thermal boundary layer produced. With a constant permeability in the upper part of the model, transient high temperature vents form near the

  9. Synthesis of anatase titania-carbon nanotubes nanocomposites with enhanced photocatalytic activity through a nanocoating-hydrothermal process

    Energy Technology Data Exchange (ETDEWEB)

    Wang Qun; Yang Dong; Chen Daimei; Wang Yabo; Jiang Zhongyi [Tianjin University, Key Laboratory for Green Chemical Technology, School of Chemical Engineering and Technology (China)], E-mail: zhyjiang@tju.edu.cn

    2007-12-15

    Anatase TiO{sub 2} nanoparticles were covalently anchored onto acid-treated multi-walled carbon nanotubes (MWNTs) through a nanocoating-hydrothermal process to obtain TiO{sub 2}-MWNTs nanocomposites. The composition and structural properties of the nanocomposites were characterized by XRD, BET, TG, TEM, HRTEM, EDX, XPS, and FTIR, and the formation of ester-bond linkage between TiO{sub 2} nanoparticles and MWNTs was demonstrated. The enhanced photocatalytic activity of TiO{sub 2}-MWNTs nanocomposites was probed by photodegradation reaction of methylene blue under visible-light irradiation.

  10. Facile Synthesis of N-Doped BiOCl Photocatalyst by an Ethylenediamine-Assisted Hydrothermal Method

    OpenAIRE

    Guihua Chen; Gangling Chen; Yong Wang; Qingfeng Wang; Zhen Zhang

    2015-01-01

    A nitrogen doped BiOCl (N-BiOCl) photocatalyst was synthesized and characterized using an ethylenediamine-assisted hydrothermal method. The N-BiOCl sample demonstrated the same tetragonal crystal structure as the as-prepared pure BiOCl sample. SEM results indicated that N-BiOCl sample was self-assembled by nanoplates to provide an aggregated flower-like microstructure. Doped nitrogen was substituted for oxygen in the crystal lattice of BiOCl, causing a red shift for N-BiOCl sample compared to...

  11. Hydrothermal Synthesis and Characterization of Iron-tin Nanocomposite Oxides%水热法制备铁锡纳米复合氧化物及表征

    Institute of Scientific and Technical Information of China (English)

    任保平; 李娟

    2009-01-01

    以Fe(NO3)3·9H2O,SnCl4·5H2O为原料,通过改变水热反应的条件合成了铁锡纳米复合氧化物.用X射线衍射仪和透射电镜对产物的结构和微观形貌进行了表征.结果表明:在水热制备铁锡复合氧化物的过程中,通过分步控制温度法和使用不同的沉淀剂可以控制产物的粒径大小和形貌.最终得到以棒状的α-Fe2O3晶体为核,附着有SnO2粒子的纳米复合氧化物.并对复合物形成机理进行了初步探讨.%Iron-tin nanocomposite oxides were prepared by using Fe(NO3)3·9H2O and SnCl4·5H2O as raw materials under hydrothermal conditions. The structure and morphology of the products were characterized by powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). And in the synthesis process of the iron-tin nanocomposite, the size of the products could be controlled through changing the hydrothermal temperature and the precipitant of reaction. And the iron-tin nanocomposite was obtained, in which the rod-like α-Fe2O3 act as "core", while the SnO2 nanoparticles embedded on the α-Fe2O3 nanorods serve as the "shell" of the composites. A plausible formation mechanism of the nanocomposites was also discussed in the paper.

  12. Structural and Optical Properties of Group III Doped Hydrothermal ZnO Thin Films

    Science.gov (United States)

    Mughal, Asad J.; Carberry, Benjamin; Speck, James S.; Nakamura, Shuji; DenBaars, Steven P.

    2017-03-01

    In this work, we employ a simple two-step growth technique to deposit impurity doped heteroepitaxial thin films of (0001) ZnO onto (111) MgAl2O4 spinel substrates through a combination of atomic layer deposition (ALD) and hydrothermal growth. The hydrothermal layer is doped with Al, Ga, and In through the addition of their respective nitrate salts. We evaluated the effect that varying the concentrations of these dopants has on both the structural and optical properties of these films. It was found that the epitaxial ALD layer created a ZnO}} } . out-of-plane orientation and a ZnO}} } . in-plane orientation between the film and substrate. The rocking curve line widths ranged between 0.75° and 1.80° depending on dopant concentration. The optical bandgap determined through the Tauc method was between 3.28 eV and 3.39 eV and showed a Burstein-Moss shift with increasing dopant concentration.

  13. Structural and Optical Properties of Group III Doped Hydrothermal ZnO Thin Films

    Science.gov (United States)

    Mughal, Asad J.; Carberry, Benjamin; Speck, James S.; Nakamura, Shuji; DenBaars, Steven P.

    2017-01-01

    In this work, we employ a simple two-step growth technique to deposit impurity doped heteroepitaxial thin films of (0001) ZnO onto (111) MgAl2O4 spinel substrates through a combination of atomic layer deposition (ALD) and hydrothermal growth. The hydrothermal layer is doped with Al, Ga, and In through the addition of their respective nitrate salts. We evaluated the effect that varying the concentrations of these dopants has on both the structural and optical properties of these films. It was found that the epitaxial ALD layer created a ZnO}} } out-of-plane orientation and a ZnO}} } in-plane orientation between the film and substrate. The rocking curve line widths ranged between 0.75° and 1.80° depending on dopant concentration. The optical bandgap determined through the Tauc method was between 3.28 eV and 3.39 eV and showed a Burstein-Moss shift with increasing dopant concentration.

  14. Structural and Optical Properties of Group III Doped Hydrothermal ZnO Thin Films

    KAUST Repository

    Mughal, Asad J.

    2017-01-11

    In this work, we employ a simple two-step growth technique to deposit impurity doped heteroepitaxial thin films of (0001) ZnO onto (111) MgAl2O4 spinel substrates through a combination of atomic layer deposition (ALD) and hydrothermal growth. The hydrothermal layer is doped with Al, Ga, and In through the addition of their respective nitrate salts. We evaluated the effect that varying the concentrations of these dopants has on both the structural and optical properties of these films. It was found that the epitaxial ALD layer created a ⟨111⟩MgAl2O4∥⟨0001⟩ZnO out-of-plane orientation and a ⟨1¯1¯2⟩MgAl2O4∥∥⟨011¯0⟩ZnO in-plane orientation between the film and substrate. The rocking curve line widths ranged between 0.75° and 1.80° depending on dopant concentration. The optical bandgap determined through the Tauc method was between 3.28 eV and 3.39 eV and showed a Burstein-Moss shift with increasing dopant concentration.

  15. Morphology evolution of hydrothermally grown ZnO nanostructures on gallium doping and their defect structures

    Energy Technology Data Exchange (ETDEWEB)

    Pineda-Hernandez, G. [Facultad de Ingenieria Quimica, Benemerita Universidad Autonoma de Puebla, C.P. 72570 Puebla, Pue. (Mexico); Escobedo-Morales, A., E-mail: alejandroescobedo@hotmail.com [Facultad de Ingenieria Quimica, Benemerita Universidad Autonoma de Puebla, C.P. 72570 Puebla, Pue. (Mexico); Pal, U. [Instituto de Fisica, Benemerita Universidad Autonoma de Puebla, Apdo. Postal J-48, C.P. 72570 Puebla, Pue. (Mexico); Chigo-Anota, E. [Facultad de Ingenieria Quimica, Benemerita Universidad Autonoma de Puebla, C.P. 72570 Puebla, Pue. (Mexico)

    2012-08-15

    In the present article, the effect of gallium doping on the morphology, structural, and vibrational properties of hydrothermally grown ZnO nanostructures has been studied. It has been observed that incorporated gallium plays an important role on the growth kinetics and hence on the morphology evolution of the ZnO crystals. Ga doping in high concentration results in the contraction of ZnO unit cell, mainly along c-axis. Although Ga has high solubility in ZnO, heavy doping promotes the segregation of Ga atoms as a secondary phase. Incorporated Ga atoms strongly affect the vibrational characteristics of ZnO lattice and induce anomalous Raman modes. Possible mechanisms of morphology evolution and origin of anomalous Raman modes in Ga doped ZnO nanostructures are discussed. -- Highlights: Black-Right-Pointing-Pointer Ga doped ZnO nanostructures were successfully grown by hydrothermal chemical route. Black-Right-Pointing-Pointer Ga doping has strong effect on the resulting morphology of ZnO nanostructures. Black-Right-Pointing-Pointer Anomalous vibrational modes in wurtzite ZnO lattice are induced by Ga doping. Black-Right-Pointing-Pointer Incorporated Ga atoms accommodate at preferential lattice sites.

  16. Hyperspectral mapping of alteration assemblages within a hydrothermal vug at the Haughton impact structure, Canada

    Science.gov (United States)

    Greenberger, Rebecca N.; Mustard, John F.; Osinski, Gordon R.; Tornabene, Livio L.; Pontefract, Alexandra J.; Marion, Cassandra L.; Flemming, Roberta L.; Wilson, Janette H.; Cloutis, Edward A.

    2016-12-01

    Meteorite impacts on Earth and Mars can generate hydrothermal systems that alter the primary mineralogies of rocks and provide suitable environments for microbial colonization. We investigate a calcite-marcasite-bearing vug at the 23 km diameter Haughton impact structure, Devon Island, Nunavut, Canada, using imaging spectroscopy of the outcrop in the field (0.65-1.1 μm) and samples in the laboratory (0.4-2.5 μm), point spectroscopy (0.35-2.5 μm), major element chemistry, and X-ray diffraction analyses. The mineral assemblages mapped at the outcrop include marcasite; marcasite with minor gypsum and jarosite; fibroferrite and copiapite with minor gypsum and melanterite; gypsum, Fe3+ oxides, and jarosite; and calcite, gypsum, clay, microcline, and quartz. Hyperspectral mapping of alteration phases shows spatial patterns that illuminate changes in alteration conditions and formation of specific mineral phases. Marcasite formed from the postimpact hydrothermal system under reducing conditions, while subsequent weathering oxidized the marcasite at low temperatures and water/rock ratios. The acidic fluids resulting from the oxidation collected on flat-lying portions of the outcrop, precipitating fibroferrite + copiapite. That assemblage then likely dissolved, and the changing chemistry and pH resulting from interaction with the calcite-rich host rock formed gypsum-bearing red coatings. These results have implications for understanding water-rock interactions and habitabilities at this site and on Mars.

  17. Understanding the structural features of high-amylose maize starch through hydrothermal treatment.

    Science.gov (United States)

    Yang, Jianing; Xie, Fengwei; Wen, Wenqiang; Chen, Ling; Shang, Xiaoqin; Liu, Peng

    2016-03-01

    In this study, high-amylose starches were hydrothermally-treated and the structural changes were monitored with time (up to 12h) using scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), small-angle X-ray scattering (SAXS), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). When high-amylose starches were treated in boiling water, half-shell-like granules were observed by SEM, which could be due to the first hydrolysis of the granule inner region (CLSM). This initial hydrolysis could also immediately (0.5h) disrupt the semi-crystalline lamellar regularity (SAXS) and dramatically reduce the crystallinity (XRD); but with prolonged time of hydrothermal treatment (≥2 h), might allow the perfection or formation of amylose single helices, resulting in slightly increased crystallinity (XRD and DSC). These results show that the inner region of granules is composed of mainly loosely-packed amylopectin growth rings with semi-crystalline lamellae, which are vulnerable under gelatinization or hydrolysis. In contrast, the periphery is demonstrated to be more compact, possibly composed of amylose and amylopectin helices intertwined with amylose molecules, which require greater energy input (higher temperature) for disintegration.

  18. Hydrothermal synthesis of silico-manganese nanohybrid for Cu(II) adsorption from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Qiufeng, E-mail: zhuqiufeng@th.btbu.edu.cn; Wang, Liting; An, Zehuan; Ye, Hong; Feng, Xudong

    2016-05-15

    Highlights: • A novel silico-manganese nanohybrid adsorbent (SMNA) was synthesized by a hydrothermal method. • The adsorption capacities of the SMNA for Cu(II) are lower pH dependency. • As-adsorbents are very efficient at low metal concentration and substantial amounts of Cu(II) can be removed from aqueous solution. - Abstract: A novel silico-manganese nanohybrid adsorbent (SMNA) was synthesized by a facile hydrothermal method, and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), nitrogen adsorption-desorption, Fourier transform infrared spectroscopy (FT-IR) and zeta potential measurement. The adsorption of Cu(II) ions from aqueous solution on the SMNA was investigated with variations in contact time, pH and initial Cu(II) concentration. The results showed that hydrothermal method would generate nanowire/nanorod incomplete crystallite (δ-MnO{sub 2}) adsorbent. The adsorption of Cu(II) onto SMNA increased sharply within 25 min and reached equilibrium gradually. The maximum adsorption capacities of SMNA for Cu(II) were ∼40–88 mg g{sup −1}, which was lower than δ-MnO{sub 2} (92.42 mg g{sup −1}) but had a lower pH dependency. As compared with δ-MnO{sub 2}, higher adsorption capacities of SMNA (7.5–15 wt% of silica doping amount) for Cu(II) could be observed when pH of the aqueous solution was low (<4). The pseudo-second-order model was the best choice to describe the adsorption behavior of Cu(II) onto SMNA, suggesting that the removal of Cu(II) by the as-prepared adsorbents was dominated by migration of Cu(II). The possibility of Cu(II) recovery was also investigated and it revealed that SMNA was a promising recyclable adsorbent for removal of heavy metal ions in water and wastewater treatment.

  19. Hydrothermal synthesis of lanthanide (hydr)oxide micro/nanorods in presence of tetrabutylammonium hydroxide

    Institute of Scientific and Technical Information of China (English)

    李银艳; 徐时清

    2016-01-01

    Uniform and well-defined lanthanide hydroxide and oxide micro/nanorods Ln(OH)3(Ln=La, Pr, Sm, Eu, Gd, Er) and Gd(OH)3:Eu3+, Gd2O3:Eu3+ were successfully synthesized through a green and facile hydrothermal method. Tetrabutylammonium hydroxide (TBAH) and lanthanide nitrides were used as the hydrothermal precursors without the addition of any templates/surfactants. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and photoluminescence (PL) spectra. The result demonstrated that lanthanide hydroxide micro/nanorods with 20–80 nm in diameter and 50–450 in length were obtained. The size of the Ln(OH)3 (Ln=La, Pr, Sm, Eu, Gd, Er) rods increased with the increase of the atomic number. The size of the Gd(OH)3:Eu3+ rods decreased with the increase of pH value by modulating the amount of the TBAH solution. The as-formed product via the hydrothermal process, Gd(OH)3:Eu3+, could be transformed to Gd2O3:Eu3+ with the same morphology and a slight shrinking in size after a post annealing process. It is a facial method to synthesize photoluminescent nanomaterial of Gd2O3:Eu3+. The Gd2O3:Eu3+ microrods exhibited strong red emission corresponding to5D0→7F2 transition (610 nm) of Eu3+ under UV light excitation (257 nm).

  20. Hydrothermal Synthesis and Crystal Structure of a Zero-Dimensional Copper(Ⅰ) Complex with Isophthalic Acid and Medpq Ligands%由间苯二甲酸和Medpq配体构筑的一种新型零维铜(Ⅰ)的配合物的水热合成及晶体结构测定

    Institute of Scientific and Technical Information of China (English)

    黄艳菊; 崔运成; 杜刚

    2009-01-01

    A metal-organic Complex [Cu_2(ipt)(Medpq)_2]_n (ipt=isophthalic acid, Medpq=2-methyldipyrido[3,2-f:2',3'-h]quinoxaline) 1 has been hydrothermally synthesized and structurally characterized by elemental analysis, IR spectrum, TG and single-crystal X-ray diffraction. Title compound crystallizes in the monoclinic system, space group C2/c, with a=2.389 2(6) nm, 6=0.709 60(18) nm, c=1.922 2(5) nm, β=108.655(3), V =3.087 8(14) nm~3, C_(38)H_(24)Cu_2 N_8O_4, M_r=783.73, D_c=1.686 g·cm~(-3), Z=4, the final R=0.0554 and wR=0.1285. In the crystal structure, the copper atom is three-coordinated with one carboxylate oxygen atom from carboxylate groups and two nitrogen atoms from Medpq ligand, showing a slightly distorted triangle geometry. Furthermore, it exhibits a zero-dimensional structure with ipt-Cu- medpq as building units.

  1. Relationship between Crystal Shape, Photoluminescence, and Local Structure in SrTiO3 Synthesized by Microwave-Assisted Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Luís F. da Silva

    2012-01-01

    Full Text Available This paper describes the effect of using different titanium precursors on the synthesis and physical properties of SrTiO3 powders obtained by microwave-assisted hydrothermal method. X-ray diffraction measurements, X-ray absorption near-edge structure (XANES spectroscopy, field emission scanning electron microscopy (FE-SEM, and high-resolution transmission electron microscopy (HRTEM were carried out to investigate the structural and optical properties of the SrTiO3 spherical and cubelike-shaped particles. The appropriate choice of the titanium precursor allowed the control of morphological and photoluminescence (PL properties of SrTiO3 compound. The PL emission was more intense in SrTiO3 samples composed of spherelike particles. This behavior was attributed to the existence of a lower amount of defects due to the uniformity of the spherical particles.

  2. Nanostructural evolution of one-dimensional BaTiO3 structures by hydrothermal conversion of vertically aligned TiO2 nanotubes

    Science.gov (United States)

    Muñoz-Tabares, J. A.; Bejtka, K.; Lamberti, A.; Garino, N.; Bianco, S.; Quaglio, M.; Pirri, C. F.; Chiodoni, A.

    2016-03-01

    The use of TiO2 nanotube (NT) arrays as templates for hydrothermal conversion of one-dimensional barium titanate (BaTiO3) structures is considered a promising synthesis approach, even though the formation mechanisms are not yet fully understood. Herein we report a nanostructural study by means of XRD and (HR)TEM of high aspect ratio TiO2-NTs hydrothermally converted into BaTiO3. The nanostructure shows two different and well-defined regions: at the top the conversion involves complete dissolution of NTs and subsequent precipitation of BaTiO3 crystals by homogeneous nucleation, followed by the growth of dendritic structures by aggregation and oriented attachment mechanisms. Instead, at the bottom, the low liquid/solid ratio, due to the limited amount of Ba solution that infiltrates the NTs, leads to the rapid crystallization of such a solution into BaTiO3, thus allowing the NTs to act as a template for the formation of highly oriented one-dimensional nanostructures. The in-depth analysis of the structural transformations that take place during the formation of the rod-like arrays of BaTiO3 could help elucidate the conversion mechanism, thus paving the way for the optimization of the synthesis process in view of new applications in energy harvesting devices, where easy and low temperature processing, controlled composition, morphology and functional properties are required.The use of TiO2 nanotube (NT) arrays as templates for hydrothermal conversion of one-dimensional barium titanate (BaTiO3) structures is considered a promising synthesis approach, even though the formation mechanisms are not yet fully understood. Herein we report a nanostructural study by means of XRD and (HR)TEM of high aspect ratio TiO2-NTs hydrothermally converted into BaTiO3. The nanostructure shows two different and well-defined regions: at the top the conversion involves complete dissolution of NTs and subsequent precipitation of BaTiO3 crystals by homogeneous nucleation, followed by the

  3. Two-step hydrothermal synthesis of Ru-Sn oxide composites for electrochemical supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Chi-Chang; Chang, Kuo-Hsin; Wang, Chen-Ching [Department of Chemical Engineering, National Chung Cheng University, Chia-Yi 621 (China)

    2007-03-20

    A two-step hydrothermal process was developed to synthesize hydrous 30RuO{sub 2}-70SnO{sub 2} composites with much better capacitive performances than those fabricated through the normal hydrothermal process, co-annealing method, or modified sol-gel procedure. A very high specific capacitance of RuO{sub 2} (C{sub S,Ru}), ca. 1150 F g{sup -1}, was obtained when this composite was synthesized via this two-step hydrothermal process with annealing in air at 150 C for 2 h. The voltammetric currents of this annealed composite were found to be quasi-linearly proportional to the scan rate of CV (up to 500 mV s{sup -1}), demonstrating its excellent power property. From Raman, UV-vis spectroscopic and TEM analyses, the reduction in mean particulate size is clearly found for this two-step oxide composite, attributable to the co-precipitation of (Ru{sub {delta}}Sn{sub 1-{delta}})O{sub 2}.xH{sub 2}O onto partially dissolved SnO{sub 2}.xH{sub 2}O and the formation of (Ru{sub {delta}}Sn{sub 1-{delta}})O{sub 2}.xH{sub 2}O crystallites in the second step. This effect significantly promotes the utilization of RuO{sub 2} (i.e., very high C{sub S,Ru}). The excellent capacitive performances, very similar to that of RuO{sub 2}.xH{sub 2}O, suggest the deposition of RuO{sub 2}-enriched (Ru{sub {delta}}Sn{sub 1-{delta}})O{sub 2}.xH{sub 2}O onto SnO{sub 2}.xH{sub 2}O seeds as well as the individual formation of (Ru{sub {delta}}Sn{sub 1-{delta}})O{sub 2}.xH{sub 2}O crystallites in the second hydrothermal step. (author)

  4. Synthesis of Hydrotalcite-like Compound Pillared by Hetero-polyacid Anions in a Hydrothermal System

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Hetero-polyacid anions (PW12O403-)-pillared hydrotalcite-like compound is directly and hydrothermally synthesized by the hot solution method. FTIR and XRD show that PW12O403- has been incorporated into the interstitial space with the dimension of 0.917 nm. The state of PW12O403- anion between the hydrotalcite sheets was also discussed. The title product can be expressed by formula [Zn0.68Al0.32(OH)2][PW12O40] 0. 113H2O after a serious study of TGA and chemical analysis.

  5. Microwave Hydrothermal Synthesis of Terbium Ions Complexed with Porous Graphene for Effective Absorbent for Organic Dye.

    Science.gov (United States)

    Chen, Keqin; Gao, Hui; Bai, Bowei; Liu, Wenjing; Li, Xiaolong

    2017-12-01

    A luminescent terbium ions/reduced graphene oxide complex (Tb-RGO) was successfully and rapidly synthesized by the microwave hydrothermal reaction via the interactions between terbium ions and the active oxygen functional groups of graphene oxide. The as-prepared material was porous stacked by multilayer graphene in all directions. Thus, the resulting product owed the high specific surface area, high adsorption capacity and ultra-fast adsorption rate. Combined with the characteristic photoluminescence derived from terbium ions, the material has potential applications in biosensing and environmental protection.

  6. Facile Hydrothermal Synthesis of SnO2 Nanospheres as Photocatalysts

    OpenAIRE

    Wenquan Hu; Xiaoguang Yuan

    2017-01-01

    Large amounts of SnO2 nanospheres are successfully synthesized through a simple and effective hydrothermal method. The as-synthesized products consist of numerous small SnO2 nanocrystals with an average diameter of 40 nm. The as-prepared SnO2 nanospheres are further used as the photocatalysts for photodegrading several organic dyes (methylene blue, methyl orange, Congo red, and rhodamine B) under UV light irradiation. The photocatalytic results show that the as-synthesized SnO2 nanospheres po...

  7. Hydrothermal Synthesis of Bi2S3 Nanostructures and ABS-Based Polymeric Nanocomposite

    Directory of Open Access Journals (Sweden)

    D. Ghanbari

    2014-04-01

    Full Text Available Bismuth sulfide nano-rods and nano-flowers were synthesized via a hydrothermal reaction at a relatively low temperature. Thioglycolic acid is used as sulfur source and capping agent simultaneously. Bi2S3 nanostructures were then added to acrylonitrile-butadiene-styrene (ABS copolymer. The thermal stability behavior of ABS filled with bismuth sulfide nano-rods were investigated by thermogravimetric analysis (TGA. Nanostructures were characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM and atomic force microscopy (AFM. The flame retardancy behavior of ABS-Bi2S3 was studied by UL-94 analysis.

  8. Microwave Hydrothermal Synthesis of Terbium Ions Complexed with Porous Graphene for Effective Absorbent for Organic Dye

    Science.gov (United States)

    Chen, Keqin; Gao, Hui; Bai, Bowei; Liu, Wenjing; Li, Xiaolong

    2017-03-01

    A luminescent terbium ions/reduced graphene oxide complex (Tb-RGO) was successfully and rapidly synthesized by the microwave hydrothermal reaction via the interactions between terbium ions and the active oxygen functional groups of graphene oxide. The as-prepared material was porous stacked by multilayer graphene in all directions. Thus, the resulting product owed the high specific surface area, high adsorption capacity and ultra-fast adsorption rate. Combined with the characteristic photoluminescence derived from terbium ions, the material has potential applications in biosensing and environmental protection.

  9. Hydrothermal Synthesis of Nickel Hydroxide Nanostructures and Flame Retardant Poly Vinyl Alcohol and Cellulose Acetate Nanocomposites

    Directory of Open Access Journals (Sweden)

    S. R. Yousefi

    2016-01-01

    Full Text Available Nickel hydroxide nanostructures were synthesized by a hydrothermal reaction. The effect of different precursors and surfactants on the morphology of nickel hydroxide nanostructures was investigated. Nanostructures were characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, scanning electron microscopy and Fourier transform infrared  spectroscopy. The influence of Ni(OH2 nanostructures on the thermal stability and flame retardancy of the poly vinyl alcohol and cellulose acetate matrix was studied using UL-94 analysis. The enhancement of thermal stability and flame retardancy of nanocomposites is due to the endothermic decomposition of Ni(OH2 and release of water which dilutes combustible gases.

  10. Nitrogen-doped graphene/ZnSe nanocomposites: hydrothermal synthesis and their enhanced electrochemical and photocatalytic activities.

    Science.gov (United States)

    Chen, Ping; Xiao, Tian-Yuan; Li, Hui-Hui; Yang, Jing-Jing; Wang, Zheng; Yao, Hong-Bin; Yu, Shu-Hong

    2012-01-24

    Nitrogen-doped graphene (GN) has great potential applications in many fields because doping with nitrogen can alter the electrical properties of graphene. It is still a challenge to develop a convenient method for synthesis of GN sheets. In this paper, we first report the synthesis of a nitrogen-doped graphene/ZnSe nanocomposite (GN-ZnSe) by a one-pot hydrothermal process at low temperature using graphene oxide nanosheets and [ZnSe](DETA)(0.5) nanobelts as precursors. ZnSe nanorods composed of ZnSe nanoparticles were found to deposit on the surface of the GN sheets. The results demonstrated that [ZnSe](DETA)(0.5) nanobelts were used not only as the source of ZnSe nanoparticles but also as the nitrogen source. Interestingly, it was found that the as-prepared nanocomposites exhibit remarkably enhanced electrochemical performance for oxygen reduction reaction and photocatalytic activities for the bleaching of methyl orange dye under visible-light irradiation. This facile and catalyst-free approach for depositing ZnSe nanoparticles onto the graphene sheets may provide an alternative way for preparation of other nanocomposites based on GN sheets under mild conditions, which show their potential applications in wastewater treatment, fuel cells, energy storage, nanodevices, and so on.

  11. Hydrothermal synthesis and characterization of a two-dimensional piperazinium cobalt–zinc phosphate via a metastable one-dimensional phase

    Energy Technology Data Exchange (ETDEWEB)

    Torre-Fernández, Laura; Khainakova, Olena A. [Departamentos de Química Física y Analítica y Química Orgánica e Inorgánica, Universidad de Oviedo-CINN, 33006 Oviedo (Spain); Espina, Aránzazu [Servicios Científico Técnicos, Universidad de Oviedo, 33006 Oviedo (Spain); Amghouz, Zakariae, E-mail: amghouz.uo@uniovi.es [Servicios Científico Técnicos, Universidad de Oviedo, 33006 Oviedo (Spain); Khainakov, Sergei A. [Servicios Científico Técnicos, Universidad de Oviedo, 33006 Oviedo (Spain); Alfonso, Belén F.; Blanco, Jesús A. [Departamento de Física, Universidad de Oviedo, 33007 Oviedo (Spain); García, José R.; García-Granda, Santiago [Departamentos de Química Física y Analítica y Química Orgánica e Inorgánica, Universidad de Oviedo-CINN, 33006 Oviedo (Spain)

    2015-05-15

    A two-dimensional piperazinium cobalt–zinc phosphate, formulated as (C{sub 4}N{sub 2}H{sub 12}){sub 1.5}(Co{sub 0.6}Zn{sub 0.4}){sub 2}(HPO{sub 4}){sub 2}(PO{sub 4})·H{sub 2}O (2D), was synthesized under hydrothermal conditions. The crystal structure was determined using single-crystal X-ray diffraction data (monoclinic P2{sub 1}/c, a=8.1165(3) Å, b=26.2301(10) Å, c=8.3595(4) Å, and β=110.930(5)°) and the hydrogen atom positions were optimized by DFT calculations. A single-crystal corresponding to one-dimensional metastable phase, (C{sub 4}N{sub 2}H{sub 12})Co{sub 0.3}Zn{sub 0.7}(HPO{sub 4}){sub 2}·H{sub 2}O (1D), was also isolated and the crystal structure was determined (monoclinic P2{sub 1}/c, a=8.9120(6) Å, b=14.0290(1) Å, c=12.2494(5) Å, and β=130.884(6)°). The bulk was characterized by chemical (C–H–N) analysis, powder X-ray diffraction (PXRD), powder X-ray thermodiffractometry (HT-XRD), transmission electron microscopy (STEM(DF)-EDX and EFTEM), and thermal analysis (TG/SDTA-MS), including activation energy data of its thermal decomposition. The magnetic susceptibility and magnetization measurements show no magnetic ordering down to 4 K. - Graphical abstract: Hydrothermal synthesis and structural characterization of a two-dimensional piperazinium cobalt–zinc phosphate, (C{sub 4}N{sub 2}H{sub 12}){sub 1.5}(Co{sub 0.6}Zn{sub 0.4}){sub 2}(HPO{sub 4}){sub 2}(PO{sub 4})·H{sub 2}O (2D), have been reported. The crystal structure of a one-dimensional piperazinium cobalt–zinc phosphate, (C{sub 4}N{sub 2}H{sub 12})Co{sub 0.3}Zn{sub 0.7}(HPO{sub 4}){sub 2}·H{sub 2}O (1D) a metastable phase during the hydrothermal synthesis, was also determined. The thermal behavior of 2D compound is strongly dependent on the selected heating rate and the magnetic susceptibility and magnetization measurements show no magnetic ordering down to 4 K. - Highlights: • A 2D piperazinium cobalt–zinc phosphate has been synthesized and characterized. • Crystal

  12. Hydrothermal synthesis of cerium titanate nanorods and its application in visible light photocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Pei, L.Z., E-mail: lzpei@ahut.edu.cn; Liu, H.D.; Lin, N.; Yu, H.Y., E-mail: yuhy@ahut.edu.cn

    2015-01-15

    Highlights: • Cerium titanate nanorods have been synthesized by a simple hydrothermal process. • The size of the cerium titanate nanorods can be controlled by growth conditions. • Cerium titanate nanorods exhibit good photocatalytic activities for methyl blue. - Abstract: Cerium titanate nanorods have been prepared via a hydrothermal process using sodium dodecyl sulfate (SDS) as the surfactant. The cerium titanate nanorods have been analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), and ultraviolet–visible (UV–vis) diffuse reflectance spectrum. XRD shows that the nanorods are composed of CeTi{sub 21}O{sub 38} phase. Electron microscopy observations indicate that the nanorods have good single crystalline nature. The diameter and length of the nanorods are about 50–200 nm and 1–2 μm, respectively. Cerium titanate nanorods have a band gap of 2.65 eV. The photocatalytic activities of the nanorods have been investigated by degrading methylene blue (MB) under visible light irradiation. MB solution with the concentration of 10 mg L{sup −1} can be degraded totally with the irradiation time increasing to 240 min. Cerium titanate nanorods exhibit great potential in photocatalytic degradation of MB under visible light irradiation.

  13. Hydrothermal synthesis of silico-manganese nanohybrid for Cu(II) adsorption from aqueous solution

    Science.gov (United States)

    Zhu, Qiufeng; Wang, Liting; An, Zehuan; Ye, Hong; Feng, Xudong

    2016-05-01

    A novel silico-manganese nanohybrid adsorbent (SMNA) was synthesized by a facile hydrothermal method, and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), nitrogen adsorption-desorption, Fourier transform infrared spectroscopy (FT-IR) and zeta potential measurement. The adsorption of Cu(II) ions from aqueous solution on the SMNA was investigated with variations in contact time, pH and initial Cu(II) concentration. The results showed that hydrothermal method would generate nanowire/nanorod incomplete crystallite (δ-MnO2) adsorbent. The adsorption of Cu(II) onto SMNA increased sharply within 25 min and reached equilibrium gradually. The maximum adsorption capacities of SMNA for Cu(II) were ∼40-88 mg g-1, which was lower than δ-MnO2 (92.42 mg g-1) but had a lower pH dependency. As compared with δ-MnO2, higher adsorption capacities of SMNA (7.5-15 wt% of silica doping amount) for Cu(II) could be observed when pH of the aqueous solution was low (removal of Cu(II) by the as-prepared adsorbents was dominated by migration of Cu(II). The possibility of Cu(II) recovery was also investigated and it revealed that SMNA was a promising recyclable adsorbent for removal of heavy metal ions in water and wastewater treatment.

  14. Hydrothermal synthesis of BaTiO 3 nanoparticles using a supercritical continuous flow reaction system

    Science.gov (United States)

    Hayashi, Hiromichi; Noguchi, Takio; Islam, Nazrul M.; Hakuta, Yukiya; Imai, Yusuke; Ueno, Nobuhiko

    2010-06-01

    Highly crystalline BaTiO 3 nanoparticle was synthesized rapidly by hydrothermal reaction in supercritical water using a continuous flow reactor. The reactants of TiO 2 sol (or TiCl 4)/Ba(NO 3) 2 mixed solution and KOH solution were used as starting materials and that was heated quickly up to 400 °C under the pressure of 30 MPa for 8 ms as reaction time. The XRD results revealed that the crystal phase of the obtained particles was cubic BaTiO 3, indicating that the hydrothermal reaction in supercritical water was successfully proceeded under present reaction conditions. Primarily particle size of the BaTiO 3 nanoparticle was determined by means of BET surface area, as small as less than 10 nm with decreasing the reaction pH. In contrast, dispersed particle size in solution measured by DLS (dynamic light scattering) technique decreased from 260 to 90 nm with increasing the reactants concentration. Aggregation of BaTiO 3 nanoparticles might be depressed in the presence of coexisting nitrate anions.

  15. Crystal structure, microstructure and magnetic properties of Ni nanoparticles elaborated by hydrothermal route

    Energy Technology Data Exchange (ETDEWEB)

    Bouremana, A., E-mail: ahmed.bouremana@gmail.com [LPM, Faculty of Sciences, USTHB, BP 32, El-Alia, Bab Ezzouar, Algiers (Algeria); Guittoum, A.; Hemmous, M.; Rahal, B. [Nuclear Research Centre of Algiers, 02 Bd Frantz Fanon, BP 399, Alger-Gare, Algiers (Algeria); Sunol, J.J. [Departament de Fisica, Universitat de Girona, Campus de Montillivi, Girona 17071 (Spain); Martínez-Blanco, D. [SCTs, University of Oviedo, EPM, 33600 Mieres (Spain); Blanco, J.A. [Department of Physics, University of Oviedo, CalvoSotelo St., 33007 Oviedo (Spain); Gorria, Pedro [Department of Physics, EPI, University of Oviedo, 33203 Gijón (Spain); Benrekaa, N. [LPM, Faculty of Sciences, USTHB, BP 32, El-Alia, Bab Ezzouar, Algiers (Algeria)

    2014-05-01

    We report on the crystal structure, microstructure and magnetic properties of Ni nanoparticles (NPs), with an average diameter of around 40 nm, produced by hydrothermal method. A series of Ni powders was synthesized at relatively low temperature (140 °C) by varying the NaOH concentration. The crystal structure, microstructure and magnetic properties were investigated by means of XRD, MEB coupled to EDX and VSM magnetometry. The XRD patterns show Bragg reflections corresponding to Ni with face centred cubic (fcc) crystal structure. EDX spectra confirm the purity of Ni powders. Moreover, the SEM micrographs show that the Ni-NPs are agglomerated forming entities of 1–5 μm in average size with different morphologies that change as the NaOH concentration increases. While those entities exhibit a flower-like form at the lowest concentration, a dendritic shape appears for the highest one. The room temperature values for the coercive field (<200 Oe) and saturation magnetization (≈52 Am{sup 2}/kg) were obtained from the magnetic hysteresis loops. We discuss about the influence of the particle morphology on the magnetic behaviour. - Highlights: • High purity Ni nanoparticles have been elaborated by hydrothermal method under the presence of sodium hydroxide with different concentrations. • The variation of the NaOH concentration seems to be irrelevant for the NP size, but plays an important role in the morphology. • The shape of Ni nanoparticles changes from spherical cores to flower-like entities and then to dendritic ones as the NaOH concentration increases. • The coercive field depends on the shape of nanoparticles.

  16. Hydrothermal synthesis of high-quality type-II CdTe/CdSe quantum dots with near-infrared fluorescence.

    Science.gov (United States)

    Wang, Jing; Han, Heyou

    2010-11-01

    A simple hydrothermal method is developed for the synthesis of high-quality, water-soluble, and near-infrared (NIR)-emitting type-II core/shell CdTe/CdSe quantum dots (QDs) by employing thiol-capped CdTe QDs as core templates and CdCl(2) and Na(2)SeO(3) as shell precursors. Compared with the original CdTe core QDs, the core/shell CdTe/CdSe QDs exhibit an obvious red-shifted emission, whose color can be tuned between visible and NIR regions (620-740 nm) by controlling the thickness of the CdSe shell. The photoluminescence quantum yield (PL QY) of CdTe/CdSe QDs with an optimized thickness of the CdSe shell can reach up to 44.2% without any post-preparative treatment. Through a thorough study of the core/shell structure by high-resolution transmission electron microscopy (HRTEM), ultraviolet-visible (UV-vis) absorption spectra, fluorescence spectra, X-ray powder diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), the as-prepared CdTe/CdSe QDs demonstrate good monodispersity, hardened lattice structure and excellent photostability, offering a great potential for biological application.

  17. High-throughput continuous hydrothermal flow synthesis of Zn-Ce oxides: unprecedented solubility of Zn in the nanoparticle fluorite lattice.

    Science.gov (United States)

    Kellici, Suela; Gong, Kenan; Lin, Tian; Brown, Sonal; Clark, Robin J H; Vickers, Martin; Cockcroft, Jeremy K; Middelkoop, Vesna; Barnes, Paul; Perkins, James M; Tighe, Christopher J; Darr, Jawwad A

    2010-09-28

    High-throughput continuous hydrothermal flow synthesis has been used as a rapid and efficient synthetic route to produce a range of crystalline nanopowders in the Ce-Zn oxide binary system. High-resolution powder X-ray diffraction data were obtained for both as-prepared and heat-treated (850 degrees C for 10 h in air) samples using the new robotic beamline I11, located at Diamond Light Source. The influence of the sample composition on the crystal structure and on the optical and physical properties was studied. All the nanomaterials were characterized using Raman spectroscopy, UV-visible spectrophotometry, Brunauer-Emmett-Teller surface area and elemental analysis (via energy-dispersive X-ray spectroscopy). Initially, for 'as-prepared' Ce(1-x)Zn(x)O(y), a phase-pure cerium oxide (fluorite) structure was obtained for nominal values of x=0.1 and 0.2. Biphasic mixtures were obtained for nominal values of x in the range of 0.3-0.9 (inclusive). High-resolution transmission electron microscopy images revealed that the phase-pure nano-CeO(2) (x=0) consisted of ca 3.7 nm well-defined nanoparticles. The nanomaterials produced herein generally had high surface areas (greater than 150 m(2) g(-1)) and possessed combinations of particle properties (e.g. bandgap, crystallinity, size, etc.) that were unobtainable or difficult to achieve by other more conventional synthetic methods.

  18. Surfactant-assisted hydrothermal synthesis of TiO2/reduced graphene oxide nanocomposites and their photocatalytic performances

    Science.gov (United States)

    Hu, Ju; Li, Hansheng; Muhammad, Sohail; Wu, Qin; Zhao, Yun; Jiao, Qingze

    2017-09-01

    Titanium dioxide/reduced graphene oxide nanocomposites (TiO2/RGO-X, X=S, T or C, was denoted sodium dodecyl benzene sulfonate, Triton X-100 and cetyl trimethyl ammonium bromide, respectively) were synthesized using a one-step surfactant-assisted hydrothermal method. The characterization of phase structure and morphology of the as-obtained nanocomposites reveals that TiO2 in the TiO2/RGO-X exhibits the morphologies of nanoparticles, nanowires and array-like nanowires on the surface of RGO, respectively. Compared with the control TiO2/RGO nanocomposite, TiO2/RGO-X presents an excellent photocatalytic activity. With uniform array-like TiO2 nanowires on the surface of RGO, the TiO2/RGO-C shows a significant enhancement in the photocatalytic efficiency. Besides, a deeper insight into the growth mechanism of TiO2/RGO nanocomposites is put forward. This work indicates that the surfactant-assisted hydrothermal method is an effective approach to improve the structure, morphology and photocatalytic performance of TiO2/RGO composites. Moreover, the surfactants with various types can interact with the precursors of TiO2 and RGO in different ways.

  19. A Facile Hydrothermal Route for Synthesis of ZnS Hollow Spheres with Photocatalytic Degradation of Dyes Under Visible Light

    Science.gov (United States)

    Han, Zh.; Wang, N.; Zhang, H.; Yang, X.

    2017-01-01

    A facile hydrothermal method was employed for the synthesis of ZnS hollow spheres by using thioglycolic acid (TGA) as a capping agent under hydrothermal condition. The obtained products were characterized by X-ray powder diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS). No diffraction peaks from other crystalline forms were detected, the synthesized ZnS hierarchical hollow spheres were relatively pure. The photocatalytic activities of as-synthesized samples were evaluated by the degradation of methyl orange (MO) and rhodamine B (RhB) under the condition of visible-light irradiation. The higher the initial MO and RhB concentrations, the longer it takes to reach the same residual concentration, implying that the apparent rates of MO and RhB degradation decrease with increase in the initial MO and RhB concentration. The increase of photocatalyst dosage from 0.2 to 0.6 g/L results in a sharp increase of the photodegradation efficiency from 68.50 to 92.66% after 180 min of visible-light irradiation for MO degradation, and the increase of photocatalyst dosage from 0.2 to 0.4 g/L results in a distinct increase of the photodegradation efficiency from 65.72 to 90.85% after 180 min of visible-light irradiation for RhB. The elution of intermediates generated in the photocatalytic mineralization of MO and RhB resulted in an increase in total organic carbon (TOC) level, leading to the difference between TOC removal rate and MO and RhB decolorization rates.

  20. Hydrothermal synthesis of h-MoO{sub 3} microrods and their gas sensing properties to ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yueli; Yang, Shuang; Lu, Yu [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070 (China); Podval’naya, Natal’ya V. [Institute of Solid State Chemistry, Ural Branch of the Russian Academy of Science, Ekaterinburg 620990 (Russian Federation); Chen, Wen, E-mail: chenw@whut.edu.cn [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070 (China); Zakharova, Galina S., E-mail: volkov@ihim.uran.ru [Institute of Solid State Chemistry, Ural Branch of the Russian Academy of Science, Ekaterinburg 620990 (Russian Federation)

    2015-12-30

    Highlights: • A simple hydrothermal acid-free method for the synthesis of h-MoO{sub 3} microrods with the hexagonal cross-section is reported. • The h-MoO{sub 3} phase is transformed to α-MoO{sub 3} at 439 °C. • The h-MoO{sub 3} microrods were employed to fabricate gas sensors to detect ethanol. • Sensor showed highest response with a sensitivity of 8.24–500 ppm C{sub 2}H{sub 5}OH at operating temperature of 332 °C. - Abstract: Hexagonal molybdenum trioxide (h-MoO{sub 3}) microrods were successfully synthesized via a novel and facile hydrothermal route from peroxomolybdate solution with the presence of NH{sub 4}Cl as the mineralizer. A variety of the techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry combined with the thermal gravimetric analysis (DSC–TG) were used to characterize the product. The gas sensing test indicates that h-MoO{sub 3} microrods have a good response to 5–500 ppm ethanol in the range of 273–380 °C, and the optimum operating temperature is 332 °C with a high sensitivity of 8.24 to 500 ppm ethanol. Moreover, it also has a good selectivity toward ethanol gas if compared with other gases, such as ammonia, methanol and toluene. The sensing mechanism of h-MoO{sub 3} microrods to ethanol was also discussed.

  1. Structure of hybrid organic-inorganic sols for the preparation of hydrothermally stable membranes

    NARCIS (Netherlands)

    Castricum, H.L.; Sah, A.; Geenevasen, J.A.J.; Kreiter, R.; Blank, D.H.A.; Vente, J.F.; ten Elshof, J.E.

    2008-01-01

    A procedure for the preparation of hybrid sols for the synthesis of organic-inorganic microporous materials and thin film membranes is reported. We describe silane reactivity and sol structure for acid-catalysed colloidal sols from mixtures of either tetraethylorthosilicate (TEOS) and methyltriethox

  2. Hollow carbonated hydroxyapatite microspheres with mesoporous structure: hydrothermal fabrication and drug delivery property.

    Science.gov (United States)

    Guo, Ya-Jun; Wang, Ying-Ying; Chen, Ting; Wei, Yi-Ting; Chu, Lian-Feng; Guo, Ya-Ping

    2013-08-01

    Hollow carbonated hydroxyapatite microspheres with mesoporous structure (HCHAs) have been fabricated by using calcium carbonated microspheres as sacrificial templates according to the following routes: (i) the in situ deposit of carbonated hydroxyapatite on the surfaces of CaCO3 microspheres by hydrothermal method and (ii) the removal of CaCO3 by chemical etching. The HCHAs consist of a hollow core and a mesoporous shell. Interestingly, the shell of the microspheres is constructed by carbonated hydroxyapatite nanoplates as building blocks. Moreover, these nanoplates are composed of many smaller nanoparticles with different crystal orientations, and the mesopores exist among these nanoparticles. The HCHAs exhibit the high drug-loading capacity and sustained drug release property, suggesting that the hierarchically porous microspheres have great potentials for bone-implantable drug-delivery applications. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Structural and optical characterization and efficacy of hydrothermal synthesized Cu and Ag doped zinc oxide nanoplate bactericides

    Energy Technology Data Exchange (ETDEWEB)

    Abinaya, C.; Marikkannan, M.; Manikandan, M. [Department of Materials Science, School of Chemistry, Madurai Kamaraj University, Madurai, 625 021, Tamil Nadu (India); Mayandi, J., E-mail: jeyanthinath@yahoo.co.in [Department of Materials Science, School of Chemistry, Madurai Kamaraj University, Madurai, 625 021, Tamil Nadu (India); Department of Materials Science and Engineering, Michigan Technological University, Houghton, 49931 1295, MI (United States); Suresh, P.; Shanmugaiah, V. [Department of Microbial Technology, School of Biological Sciences, Madurai Kamaraj University, Madurai, 625 021, Tamil Nadu (India); Ekstrum, C. [Department of Materials Science and Engineering, Michigan Technological University, Houghton, 49931 1295, MI (United States); Pearce, J.M. [Department of Materials Science and Engineering, Michigan Technological University, Houghton, 49931 1295, MI (United States); Department of Electrical & Computer Engineering, Michigan Technological University, Houghton, 49931 1295, MI (United States)

    2016-12-01

    This study reports on a novel synthesis of pure zinc oxide and both Cu and Ag doped ZnO nanoplates using a simple and low-cost hydrothermal method. The structural and optical properties of the nanoplates were quantified and the materials were tested for antibacterial activity. X-ray diffraction revealed the formation of the wurtzite phase of ZnO and scanning and transmission electron microscopy showed the formation of randomly oriented ZnO nanoplates, having a thickness less than 80 nm and diameter less than 350 nm. The elemental analyses of both the pure and doped samples were evaluated by energy dispersive X-ray spectrometry. The FTIR spectra of ZnO nanomaterials showed the predictable bands at 3385 cm{sup −1} (O−H stretching), 1637 cm{sup −1} (stretching vibration of H{sub 2}O), 400 cm{sup −1}–570 cm{sup −1} (M−O stretching). The as synthesized samples showed a strong absorption peak in the UV region (∼376 nm) and a near band edge emission at 392 nm with some defect peaks in the visible region. From the XPS spectra the oxidation states of Zn, Cu and Ag were found to be +2, +2 and 0 respectively. Escherichia coli, Staphylococcus aureus and Salmonella typhi bacteria were used to evaluate the antibacterial activity of undoped and doped ZnO. Ag doped ZnO exhibited low minimum inhibitory concentration (MIC) values as 40 μg/ml for E. coli and S. aureus and 20 μg/ml for S. typhi, which are comparable to commercial antibiotics without optimization. Further, these chemically modified nanoparticles will be applicable in the development of medicine to control the spread and infection of a variety of bacterial strains. - Highlights: • Distinct ZnO nanoplates were successfully synthesized by facile hydrothermal method. • Cu and Ag doped ZnO exhibits significant destruction of bacteria with low MIC value. • Ag:ZnO has a noteworthy bactericidal effect against E. coli, S. aureus &S. typhi. • It projects that, a feasible low cost industrial process can

  4. Zones of life in the subsurface of hydrothermal vents: A synthesis

    Science.gov (United States)

    Larson, B. I.; Houghton, J.; Meile, C. D.

    2011-12-01

    Subsurface microbial communities in Mid-ocean Ridge (MOR) hydrothermal systems host a wide array of unique metabolic strategies, but the spatial distribution of biogeochemical transformations is poorly constrained. Here we present an approach that reexamines chemical measurements from diffuse fluids with models of convective transport to delineate likely reaction zones. Chemical data have been compiled from bare basalt surfaces at a wide array of mid-ocean ridge systems, including 9°N, East Pacific Rise, Axial Seamount, Juan de Fuca, and Lucky Strike, Mid-Atlantic Ridge. Co-sampled end-member fluid from Ty (EPR) was used to constrain reaction path models that define diffuse fluid compositions as a function of temperature. The degree of mixing between hot vent fluid (350 deg. C) and seawater (2 deg. C) governs fluid temperature, Fe-oxide mineral precipitation is suppressed, and aqueous redox reactions are prevented from equilibrating, consistent with sluggish kinetics. Quartz and pyrite are predicted to precipitate, consistent with field observations. Most reported samples of diffuse fluids from EPR and Axial Seamount fall along the same predicted mixing line only when pyrite precipitation is suppressed, but Lucky Strike fluids do not follow the same trend. The predicted fluid composition as a function of temperature is then used to calculate the free energy available to autotrophic microorganisms for a variety of catabolic strategies in the subsurface. Finally, the relationships between temperature and free energy is combined with modeled temperature fields (Lowell et al., 2007 Geochem. Geophys., Geosys.) over a 500 m x 500 m region extending downward from the seafloor and outward from the high temperature focused hydrothermal flow to define areas that are energetically most favorable for a given metabolic process as well as below the upper temperature limit for life (~120 deg. C). In this way, we can expand the relevance of geochemical model predictions of

  5. The structure of a hydrothermal system from an integrated geochemical, geophysical, and geological approach: The Ischia Island case study

    Science.gov (United States)

    di Napoli, R.; Martorana, R.; Orsi, G.; Aiuppa, A.; Camarda, M.; de Gregorio, S.; Gagliano Candela, E.; Luzio, D.; Messina, N.; Pecoraino, G.; Bitetto, M.; de Vita, S.; Valenza, M.

    2011-07-01

    The complexity of volcano-hosted hydrothermal systems is such that thorough characterization requires extensive and interdisciplinary work. We use here an integrated multidisciplinary approach, combining geological investigations with hydrogeochemical and soil degassing prospecting, and resistivity surveys, to provide a comprehensive characterization of the shallow structure of the southwestern Ischia's hydrothermal system. We show that the investigated area is characterized by a structural setting that, although very complex, can be schematized in three sectors, namely, the extra caldera sector (ECS), caldera floor sector (CFS), and resurgent caldera sector (RCS). This contrasted structural setting governs fluid circulation. Geochemical prospecting shows, in fact, that the caldera floor sector, a structural and topographic low, is the area where CO2-rich (>40 cm3/l) hydrothermally mature (log Mg/Na ratios 150 g m-2 d-1), is clearly captured by electrical resistivity tomography (ERT) and transient electromagnetic (TEM) surveys as a highly conductive (resistivity 10,000 mg/l) and poorly conductive meteoric-derived (TDS Ischia's hydrothermal system.

  6. Fe{sub 3}O{sub 4}–CNTs nanocomposites: Inorganic dispersant assisted hydrothermal synthesis and application in lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Qixun, E-mail: qxguo@xmu.edu.cn; Guo, Pengfei; Li, Juntao, E-mail: jtli@xmu.edu.cn; Yin, Hao; Liu, Jie; Xiao, Feilong; Shen, Daoxiang; Li, Ning

    2014-05-01

    Fe{sub 3}O{sub 4}–CNTs nanocomposites with a particle size of ∼80 nm have been synthesized through an organic-free hydrothermal synthesis strategy by using Sn(OH){sub 6}{sup 2−} as an inorganic dispersant, and served as anode materials of lithium ion batteries. Nano-sized and micro-sized Fe{sub 3}O{sub 4} without CNTs have also been prepared for comparison. The cycle performances of the as-obtained Fe{sub 3}O{sub 4} are highly size-dependent. The Fe{sub 3}O{sub 4}–CNTs nanocomposites can deliver reversible discharge capacity of ∼700 mA h/g at a current density of 50 mA/g after 50 cycles. The discharge capacity of the micro-sized Fe{sub 3}O{sub 4} decreased to 171 mA h/g after 50 cycles. Our work not only provides new insights into the inorganic dispersant assisted hydrothermal synthesis of metal oxides nanocrystals but also gives guidance for finding new nanocomposites as anode materials of lithium ion batteries. - Graphical abstract: Fe{sub 3}O{sub 4}–CNTs nanocomposites have been prepared through an inorganic dispersant assisted hydrothermal synthesis strategy, and served as anode materials of lithium ion batteries with enhanced performance. - Highlights: • Sn(OH){sub 6}{sup 2−} is a good inorganic dispersant for the hydrothermal synthesis of nano Fe{sub 3}O{sub 4}. • The cycle performances of nano Fe{sub 3}O{sub 4} anode are much better than that of micro Fe{sub 3}O{sub 4} anode. • Compositing CNTs can enhance the cycle performances of nano Fe{sub 3}O{sub 4} anode.

  7. 镁皂石的水热合成与表征研究%Synthesis and Characterization of Magnesium-Saponite by Hydrothermal Way

    Institute of Scientific and Technical Information of China (English)

    姚铭; 王凯雄; 刘子阳; 施文彦; 孙红杰

    2004-01-01

    According to an optimized hydrothermal synthesis method, trioctahedral smectite(magnesium-saponite) with good long range order was synthesized within 2h at 473K. The reflection peaks of XRD pattern confirmed the trioctahedral layer structure of the product. TEM results were in good agreement with that of saponite synthesized hydrothermally at higher reaction temperatures. According to the determinations of the products synthesized under different reaction temperatures(423K, 473K, 523K, 573K), 473K was found to be a temperature threshold within short reaction time in the synthesis of sapontie having high long range order. As to the adsorption of organic cationic dye(MB), the capability of saponites with different layer charges exhibited similar capability. However, the mechanism of this kind of adsorption in the remediation of ionic type pollutants involved flocculation and ion exchange. Compared with natural montmorillonite, the synthetic saponite showed higher adsorption capability and affinity to ionic dye.%采用优化的水热合成法,在473K反应2h合成了具有优良长程有序性的2:1型三八面体蒙皂石(皂石).XRD分析表明合成产物具有典型的皂石层状结构.TEM测试发现,不同温度下合成的皂石具有类似的形态,但其层状片大小随着合成温度的提高而增大.不同温度(423K,473K,523K,573K)下水热合成实验结果表明, 473K是合成具有良好层状有序结构皂石的临界温度.不同层电荷合成皂石对于活性染料(MB)的等温吸附实验说明吸附过程包含离子交换和絮凝机理.相对于天然蒙脱石,合成皂石对于离子性染料具有更大的吸附容量和作用力.

  8. Hydrothermal Synthesis and Characterization of Perovskite Oxide AgTaO3

    Institute of Scientific and Technical Information of China (English)

    HE Li-jie; ZHANG Dong; FENG Shou-hua; ZOU Bo; CHEN Gang

    2012-01-01

    The perovskite-type AgTaO3 crystals were prepared by mild hydrothermal method and determined by powder X-ray diffraction.Rietveld refinement indicates that AgTaO3 crystallized in an orthorhombic system with the space group Pcmn.The lattice parameters are a-5.5822(1) nm,b=7.8522(2) nm and c=5.5347(1) nm,with α=β=γ=90.0°.The compound was characterized by scanning electron microscopy(SEM),X-ray photoelectron spectroscopy (XPS),high resolution transmission electron microscopy(HR-TEM) and UV-Vis diffuse reflectance spectrometry (UV-Vis DRS).The photocatalytic activity of AgTaO3 powder was evaluated by the degradation of Congo red under UV-light irradiation.The result shows that the titled compound has a high photocatalytic activity at room temperature and potential application in photocatalysis.

  9. Hydrothermal Synthesis, Characterization, and Optical Properties of Ce Doped Bi2MoO6 Nanoplates

    Directory of Open Access Journals (Sweden)

    Anukorn Phuruangrat

    2014-01-01

    Full Text Available Undoped and Ce doped Bi2MoO6 samples were synthesized by hydrothermal reaction at 180°C for 20 h. Phase, morphology, atomic vibration, and optical properties were characterized by X-ray powder diffraction (XRD, X-ray photoelectron spectroscopy (XPS, Raman spectrophotometry, Fourier transform infrared (FTIR spectroscopy, scanning electron microscopy (SEM, transmission electron microscopy (TEM, selected area electron diffraction (SAED, and UV-visible spectroscopy. In this research, the products were orthorhombic Bi2MoO6 nanoplates with the growth direction along the [0b0], including the asymmetric and symmetric stretching and bending modes of Bi–O and Mo–O. Undoped and Ce doped Bi2MoO6 samples show a strong absorption in the UV region.

  10. Hydrothermal synthesis of Bi2WO6 hierarchical flowers with their photonic and photocatalytic properties

    Science.gov (United States)

    Dumrongrojthanath, Phattharanit; Thongtem, Titipun; Phuruangrat, Anukorn; Thongtem, Somchai

    2013-02-01

    Bi2WO6 hierarchical multi-layered flower-like assemblies were synthesized by a hydrothermal method at 180 °C for 24 h. XRD patterns were specified as pure orthorhombic well-crystallized Bi2WO6 phase. Their FTIR spectra show main absorption bands at 400-1000 cm-1, assigned as the stretching modes of the Bi-O and W-O, and W-O-W bridging stretching modes. SEM analysis shows that the product was 3D hierarchical flower-like assemblies, constructed by orderly arranged 2D layers of nanoplates. The UV-visible absorption shows an absorbance in the ultraviolet region with 3.4 eV band gap. Photocatalytic activity of Bi2WO6 hierarchical flowers was determined from the degradation of rhodamine-B by Xe light at 88% for 360 min irradiation.

  11. Synthesis of MnV2O6 nanoflakes via simple hydrothermal process

    Institute of Scientific and Technical Information of China (English)

    Yi LIU; Yitai QIAN

    2008-01-01

    A single phase of monoclinic MnV2O6 nanoflakes was prepared by a hydrothermal process at 180℃ starting materials and using acetic acid to adjust the pH value of the reaction solution. The as,prepared samples were characterized by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). X,ray photoelectron spectrum (XPS) measurements further confirm the component of MnV2O6.Results indicated that the products consisted of a large quantity of compact accumulated nanoflakes,with average width of 0.85 μtm,thickness of 100 nm and lengths up to 1.7μm.

  12. Hydrothermal Synthesis and Characterization of Nd Doped One-dimensional Hexagonal CePO_4 Nanowires

    Institute of Scientific and Technical Information of China (English)

    张新奇

    2012-01-01

    One-dimensional Nd doped CePO4 hexagonal nanowires have been synthesized for the first time at 140 ℃ for 24 hours via a hydrothermal method using P123 surfactant as the template.The products were characterized by X-ray diffraction,transmission electron microscopy,photoluminescence and high-resolution transmission electron microscopy.Compared with CePO4,one-dimensional nanomaterials we have synthesized,Nd doped CePO4 nanomaterials remain their hexagonal one-dimensional morphology and smooth surface.However,their photoluminescence emissions are greatly enhanced at the wavelength of 348 nm.With their novel fluorescence-emission property,the Nd doped CePO4 nanomaterials are potential in many fields such as optics and electronics.

  13. Synthesis of tungsten oxide nanoparticles using a hydrothermal method at ambient pressure

    DEFF Research Database (Denmark)

    Ahmadi, Majid; Younesi, Reza; Guinel, Maxime J-F

    2014-01-01

    ) nanoparticles were synthesized using a simple and inexpensive low temperature and low pressure hydrothermal (HT) method. The precursor solution used for the HT process was prepared by adding hydrochloric acid to diluted sodium tungstate solutions (Na2WO4 center dot 2H(2)O) at temperatures below 5 degrees C...... of WO3 nanoparticles using this method is therefore a three step process: protonation of tungstate ions, crystallization of tungstite, and phase transformation to WO3. Furthermore, this process can be tailored. For example, we show that WO3 can be doped with cesium and that nanorods can also be obtained......Tungsten oxide (WO3) nanostructures receive sustained interest for a wide variety of applications, and especially for its usage as a photocatalyst. It is therefore important to find suitable methods allowing for its easy and inexpensive large scale production. Tungstite (WO3 center dot H2O...

  14. Hydrothermal Synthesis of Bi2MoO6 Visible-Light-Driven Photocatalyst

    Directory of Open Access Journals (Sweden)

    Anukorn Phuruangrat

    2015-01-01

    Full Text Available Bismuth molybdate (Bi2MoO6 nanoplates were synthesized by the hydrothermal reaction of bismuth nitrate and sodium molybdate as starting materials at 120–180°C for 5–20 h. X-ray diffraction (XRD, Fourier transform infrared (FTIR spectroscopy, Raman spectroscopy, and scanning electron microscopy (SEM were used to investigate the effect of reaction temperature and length of reaction time on phase and morphologies of the as-synthesized Bi2MoO6 samples. In this research, orthorhombic well-crystallized Bi2MoO6 nanoplates with the presence of stretching and bending vibrations of MoO6 and BiO6 octahedrons were detected, and the Bi2MoO6 nanoplates synthesized at 180°C for 5 h exhibit the highest photocatalytic efficiency over 96% within 100 min visible-light irradiation.

  15. Hydrothermal synthesis of amorphous MoS2nanofiber bundles via acidification of ammonium heptamolybdate tetrahydrate

    Directory of Open Access Journals (Sweden)

    Tharamani CN

    2007-01-01

    Full Text Available AbstractMoS2nanofiber bundles have been prepared by hydrothermal method using ammonium molybdate with sulfur source in acidic medium and maintained at 180 °C for several hours. The obtained black crystalline products are characterized by powder X-ray diffraction (PXRD, Fourier transform infrared spectrometer (FTIR, X-ray photoelectron spectroscopy (XPS, scanning electron microscopy (SEM and transmission electron microscopy (TEM. The PXRD pattern of the sample can be readily indexed as hexagonal 2H-MoS2. FTIR spectrum of the MoS2shows the band at 480 cm−1corresponds to the γas(Mo-S. SEM/TEM images of the samples exhibit that the MoS2nanofiber exist in bundles of 120–300 nm in diameter and 20–25 μm in length. The effects of temperature, duration and other experimental parameters on the morphology of the products are investigated.

  16. Synthesis and characterization of WO{sub 3} nanostructures prepared by an aged-hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Huirache-Acuna, R., E-mail: rafael_huirache@yahoo.it [CFATA-UNAM, Boulevard Juriquilla 3001, Juriquilla Queretaro, 76230 (Mexico); Universidad La Salle Morelia, Av. Universidad 500, Mpio. Tarimbaro Mich., 58880 (Mexico); Paraguay-Delgado, F. [Centro de Investigacion en Materiales Avanzados, S.C. CIMAV, Laboratorio Nacional de Nanotecnologia-Chihuahua, Miguel de Cervantes 120, Complejo Industrial Chihuahua, Chih., 31109 (Mexico); Albiter, M.A.; Lara-Romero, J. [Facultad de Ingenieria Quimica, Universidad Michoacana de San Nicolas de Hidalgo, Morelia Mich., 58000 (Mexico); Martinez-Sanchez, R. [Centro de Investigacion en Materiales Avanzados, S.C. CIMAV, Laboratorio Nacional de Nanotecnologia-Chihuahua, Miguel de Cervantes 120, Complejo Industrial Chihuahua, Chih., 31109 (Mexico)

    2009-09-15

    Nanostructures of tungsten trioxide (WO{sub 3}) have been successfully synthesized by using an aged route at low temperature (60 deg. C) followed by a hydrothermal method at 200 deg. C for 48 h under well controlled conditions. The material was studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Energy Dispersive Spectroscopy (EDS), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Specific Surface Area (S{sub BET}) were measured by using the BET method. The lengths of the WO{sub 3} nanostructures obtained are between 30 and 200 nm and their diameters are from 20 to 70 nm. The growth direction of the tungsten oxide nanostructures was determined along [010] axis with an inter-planar distance of 0.38 nm.

  17. Facile hydrothermal route to the controlled synthesis of -Fe2O3 1-D nanostructures

    Indian Academy of Sciences (India)

    Lixia Yang; Ying Liang; Hou Chen; Lingyan Kong; Wei Jiang

    2008-12-01

    Single-crystalline -Fe2O3 1-D nanostructures can be obtained via a facile one-step hydrothermal synthetic route. It was found that the introduction of SnCl4 played a key role in determining the composition and morphology of -Fe2O3. The addition of SnCl4 favours the formation of Fe2O3 rather than FeOOH, and the morphology can be tuned from nanorod to double-shuttle as the increase of SnCl4 concentration. The products were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and selectedarea electron diffraction (SAED). This simple method does not need any seed, catalyst, or template, thus is promising for large-scale and low-cost production.

  18. Facile Hydrothermal Synthesis of SnO2 Nanospheres as Photocatalysts

    Directory of Open Access Journals (Sweden)

    Wenquan Hu

    2017-01-01

    Full Text Available Large amounts of SnO2 nanospheres are successfully synthesized through a simple and effective hydrothermal method. The as-synthesized products consist of numerous small SnO2 nanocrystals with an average diameter of 40 nm. The as-prepared SnO2 nanospheres are further used as the photocatalysts for photodegrading several organic dyes (methylene blue, methyl orange, Congo red, and rhodamine B under UV light irradiation. The photocatalytic results show that the as-synthesized SnO2 nanospheres possess high photocatalytic activities. Compared with the degradation rates of other dyes, that of methylene blue reaches 98.5% by 30 min irradiation. It reveals that the as-prepared product might be potential candidate in wastewater purification.

  19. Hydrothermal synthesis and characterization of polycrystalline gadolinium aluminum perovskite (GdAlO3, GAP

    Directory of Open Access Journals (Sweden)

    N. Girish H.

    2015-06-01

    Full Text Available Gadolinium aluminum perovskite (GdAlO3, GAP is a promising high temperature ceramic material, known for its wide applications in phosphors. Polycrystalline gadolinium aluminum perovskites were synthesized using a precursor of co-precipitate gel of GdAlO3 by employing hydrothermal supercritical fluid technique under pressure and temperature ranging from 150 to 200 MPa and 600 to 700 °C, respectively. The resulted products of GAP were studied using the characterization techniques, such as powder X-ray diffraction analysis (XRD, infrared spectroscopy (IR, scanning electron microscopy (SEM and energy dispersive analysis of X-ray (EDX. The X-ray diffraction pattern matched well with the reported orthorhombic GAP pattern (JCPDS-46-0395.

  20. Hollow Carbon Microspheres/MnO2 Nanosheets Composites:Hydrothermal Synthesis and Electrochemical Behaviors

    Institute of Scientific and Technical Information of China (English)

    Hui-li Fan; Fen Ran; Xuan-xuan Zhang; Hai-ming Song; Xiao-qin Niu; Ling-bin Kong; Long Kang

    2015-01-01

    This article reported the electrochemical behaviors of a novel hollow carbon microspheres/manganese dioxide nanosheets (micro-HC/nano-MnO2) composite prepared by an in situ self-limiting deposition method under hydrothermal condition. The results of scanning electron microscopy reveal that MnO2 nanosheets homogeneously grow onto the surface of micro-HC to form a loose-packed microstructure. The quantity of MnO2 required in the electrode layer has thereby been reduced significantly, and higher specific capacitances have been achieved. The micro-HC/nano-MnO2 electrode presents a high capacitance of 239.0 F g-1 at a current density of 5 mA cm-2, which is a strong promise for high-rate electro-chemical capacitive energy storage applications.

  1. Hydrothermal synthesis of monodisperse α-Fe2O3 hexagonal platelets

    Institute of Scientific and Technical Information of China (English)

    Dengfeng Peng; Sadeh Beysen; Qiang Li; Yanfei Sun; Linyu Yang

    2010-01-01

    Uniformly sized α-Fe2O3 hexagonal platelets were synthesized by a hydrothermal process using Fe(OH)3suspension and large amount of NaOH.The reaction products were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),selected area electron diffraction(SAED),and a vibrating sample magnetometer(VSM).The results show that the hexagonal platelets are fine,monodisperse and consisting of single-crystals.The magnetic hysteresis(M-H)curve of the samples measured at room temperature indicates that the α-Fe2O3 micro-platelets exhibit ferromagnetic behaviors with relatively low coercivity.

  2. Synthesis of highly magnetic graphite-encapsulated FeCo nanoparticles using a hydrothermal process

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung Jae; Park, Joung Kyu [Center for Nano-Bio Fusion Research, Korea Research Institute of Chemical Technology, Daejeon, 305-600 (Korea, Republic of); Cho, Jee-Hyun; Lee, Chulhyun; Cho, Janggeun [Division of Magnetic Resonance Research, Korea Basic Science Institute, Ochang, 363-883 (Korea, Republic of); Kim, Yong-Rok, E-mail: parkjk@krict.re.kr [Department of Chemistry, Yonsei University, Seoul, 120-749 (Korea, Republic of)

    2011-09-16

    The graphite encapsulation of metal alloy magnetic nanoparticles has attracted attention for biological applications because of the high magnetization of the encapsulated particles. However, most of the synthetic methods have limitations in terms of scalability and economics because of the demanding synthetic conditions and low yields. Here, we show that well controlled graphite-encapsulated FeCo core-shell nanoparticles can be synthesized by a hydrothermal method, simply by mixing Fe/Co with sucrose as a carbon source. Various Fe/Co metal ratios were used to determine the compositional dependence of the saturation magnetization and relaxivity coefficient. Transmission electron microscopy indicated that the particle sizes were 7 nm. In order to test the capability of graphite-encapsulated FeCo nanoparticles as magnetic resonance imaging (MRI) contrast agents, these nanoparticles were solubilized in water by the nonspecific physical adsorption of sodium dodecylbenzene sulfonate.

  3. Hydrothermal synthesis and acetylene sensing properties of variety low dimensional zinc oxide nanostructures.

    Science.gov (United States)

    Zhou, Qu; Chen, Weigen; Peng, Shudi; Zeng, Wen

    2014-01-01

    Various morphologies of low dimensional ZnO nanostructures, including spheres, rods, sheets, and wires, were successfully synthesized using a simple and facile hydrothermal method assisted with different surfactants. Zinc acetate dihydrate was chosen as the precursors of ZnO nanostructures. We found that polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), glycine, and ethylene glycol (EG) play critical roles in the morphologies and microstructures of the synthesized nanostructures, and a series of possible growth processes were discussed in detail. Gas sensors were fabricated using screen-printing technology, and their sensing properties towards acetylene gas (C2H2), one of the most important arc discharge characteristic gases dissolved in oil-filled power equipments, were systematically measured. The ZnO nanowires based sensor exhibits excellent C2H2 sensing behaviors than those of ZnO nanosheets, nanorods, and nanospheres, indicating a feasible way to develop high-performance C2H2 gas sensor for practical application.

  4. The interactive effect of agitation condition and titania particle size in hydrothermal synthesis of titanate nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Safaei, Maryam; Sarraf-Mamoory, Rasoul, E-mail: rsarrafm@modares.ac.i [Tarbiat Modares University (Iran, Islamic Republic of); Rashidzadeh, Mehdi [Research Institute of Petroleum Industry (Iran, Islamic Republic of)

    2010-10-15

    The nucleation and growth mechanisms of hydrothermal synthesized nanotitanates are proposed based on the interaction effect between agitation condition and pristine titania particle size. TEM examination and N{sub 2} adsorption measurements revealed distinct morphology and textural properties depending on TiO{sub 2} particle size in constant agitation condition. Regarding to the supersaturation degree, heterogeneous nucleation dominates for nanotubes formation from large particle size of raw material. On the other hand, homogeneous nucleation determines nanospheres formation from small particle size of raw material. The nanotubes have an outer diameter ranging from 8 to 10 nm and inner diameter of 2 to 3 nm. The nanospheres have diameters ranging from 50 to 100 nm.

  5. Hydrothermal Synthesis and Acetylene Sensing Properties of Variety Low Dimensional Zinc Oxide Nanostructures

    Directory of Open Access Journals (Sweden)

    Qu Zhou

    2014-01-01

    Full Text Available Various morphologies of low dimensional ZnO nanostructures, including spheres, rods, sheets, and wires, were successfully synthesized using a simple and facile hydrothermal method assisted with different surfactants. Zinc acetate dihydrate was chosen as the precursors of ZnO nanostructures. We found that polyethylene glycol (PEG, polyvinylpyrrolidone (PVP, glycine, and ethylene glycol (EG play critical roles in the morphologies and microstructures of the synthesized nanostructures, and a series of possible growth processes were discussed in detail. Gas sensors were fabricated using screen-printing technology, and their sensing properties towards acetylene gas (C2H2, one of the most important arc discharge characteristic gases dissolved in oil-filled power equipments, were systematically measured. The ZnO nanowires based sensor exhibits excellent C2H2 sensing behaviors than those of ZnO nanosheets, nanorods, and nanospheres, indicating a feasible way to develop high-performance C2H2 gas sensor for practical application.

  6. WO3 nanorolls self-assembled as thin films by hydrothermal synthesis

    Science.gov (United States)

    Vankova, S.; Zanarini, S.; Amici, J.; Cámara, F.; Arletti, R.; Bodoardo, S.; Penazzi, N.

    2015-04-01

    We report a novel type of WO3 nanostructure, i.e. nanorolls obtained as a self-assembled thin film on a transparent conductive substrate. The mild conditions of preparation, avoiding the use of HCl, result in an eco-friendly hydrothermal method with reduced crystallization time. FESEM and HR-TEM show that WO3 nanocrystals are made of rolled nanoflakes with a telescope-like appearance at their tip. For their nano-porosity, electrochemical accessibility, good adhesion to substrates and the envisaged presence of nanocavities between the WO3 layers, these materials hold tremendous promise in nano-electronics, electrochromic devices, water photo-splitting cells, Li-ion batteries and nano-templated filters for UV radiation.We report a novel type of WO3 nanostructure, i.e. nanorolls obtained as a self-assembled thin film on a transparent conductive substrate. The mild conditions of preparation, avoiding the use of HCl, result in an eco-friendly hydrothermal method with reduced crystallization time. FESEM and HR-TEM show that WO3 nanocrystals are made of rolled nanoflakes with a telescope-like appearance at their tip. For their nano-porosity, electrochemical accessibility, good adhesion to substrates and the envisaged presence of nanocavities between the WO3 layers, these materials hold tremendous promise in nano-electronics, electrochromic devices, water photo-splitting cells, Li-ion batteries and nano-templated filters for UV radiation. Electronic supplementary information (ESI) available: Characterization techniques; additional FESEM micrographs; typical XRD pattern of WO3 nanoroll thin film; typical Nyquist plots at ambient temperature; indicative diameter and length of WO3 NR by varying the PVA chain length; effect of 2000 cycles of electrochemical switching on the STB, STC and ΔT% coloration efficiency of the WO3 NR. See DOI: 10.1039/c4nr07290a

  7. Alkaline hydrothermal synthesis of homogeneous titania microspheres with urchin-like nanoarchitectures for dye effluent treatments

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jin-Ming, E-mail: msewjm@zju.edu.cn [State Key Laboratory of Silicon Materials, Zhejiang University, ZheDa Road 38, Hangzhou 310027 (China); Song, Xiao-Mei [State Key Laboratory of Silicon Materials, Zhejiang University, ZheDa Road 38, Hangzhou 310027 (China); Yan, Mi, E-mail: mse_yanmi@zju.edu.cn [Department of Materials Science and Engineering, Zhejiang University, ZheDa Road 38, Hangzhou 310027 (China)

    2011-10-30

    Highlights: {yields} Alkali-hydrothermal treatments of a remnant of Ti-H{sub 2}O{sub 2} reaction achieve titania microspheres. {yields} Inhibited heterogeneous nucleation and low supersaturation contribute to the uniform size. {yields} Radially aligned anatase nanowires construct the microspheres. {yields} The microspheres possess a BET surface area of 45.4 m{sup 2}/g. {yields} The microspheres exhibit a high activity to assist photodegradation of rhodamine B in water. - Abstract: The heterogeneous photocatalysis technique to treat dye effluents demands micrometer-sized titania aggregates with one-dimensional nanostructures, which possess high photocatalytic activity and at the same time facilitate the catalyst-recovery from a slurry system. In this study, the solution remained after interactions between metallic Ti and hydrogen peroxide was subjected to an alkaline hydrothermal treatment. Microspheres with extremely uniform sizes of ca. 2 {mu}m in diameter were achieved after a subsequent proton exchange followed by calcination in air. The microspheres were urchin-like aggregates of radially assembled nanowires, which consisted of chain-like anatase single crystallites with an average diameter of 20-25 nm. The homogeneous microspheres calcinated at 600 {sup o}C possessed a surface area of 45.4 m{sup 2}/g and exhibited an excellent activity to assist photodegradation of rhodamine B in water, which is significantly higher than that of P25 titania nanoparticles. Because of the much easier recovery of the photocatalyst, the homogeneous microspheres synthesized herein may find practical applications in efficient photocatalytic treatments of dye effluents.

  8. Neutron scattering studies of structure, hydrothermal stability and transport in porous silica catalyst supports

    Science.gov (United States)

    Pollock, Rachel A.

    Mesoporous materials are interesting as catalyst supports, because molecules can move efficiently in and out of the pore network, but they must be stable in water if they are to be used for the production of biofuels. Before investigating hydrothermal stability and transport properties, the pore structure of SBA-15 was characterized using small angle neutron scattering (SANS) and non-local density functional theory (NLDFT) analysis of nitrogen sorption isotherms. A new Contrast Matching SANS method, using a range of probe molecules to directly probe the micropore size, gave a pore size distribution onset of 6 ± 0.2 Å, consistent with cylindrical pores formed from polymer template strands that unravel into the silica matrix. Diffraction intensity analysis of SANS measurements, combined with pore size distributions calculated from NLDFT, showed that the secondary pores are distributed relatively uniformly throughout the silica framework. The hydrothermal stability of SBA-15 was evaluated using a post-calcination hydrothermal treatment in both liquid and vapor phase water. The results were consistent with a degradation mechanism in which silica dissolves from regions of small positive curvature, e.g. near the entrance to the secondary pores, and is re-deposited deeper into the framework. Under water treatment at 115 °C, the mesopore diameter increases and the intra-wall void fraction decreases significantly. The behavior is similar for steam treatment, but occurs more slowly, suggesting that transport is faster when condensation occurs in the pores. Quasielastic neutron scattering (QENS) measurements of methane in SBA-15 probed the rotational and translational motion as a function of temperature and loading. A qualitative analysis of the QENS data suggested that for the initial dose of methane at 100 K, the self diffusion constant is similar in magnitude to literature values for methane in ZSM-5 and Y-zeolite, showing that the secondary pores trap methane and limit

  9. Synthesis and characterization of Co-doped zinc oxide nanorods prepared by ultrasonic spray pyrolysis and hydrothermal methods

    Science.gov (United States)

    Febrianti, Y.; Putri, N. A.; Sugihartono, I.; Fauzia, V.; Handoko, D.

    2017-07-01

    ZnO nanorods was synthesized by using ultrasonic spray pyrolysis deposition process and grown by hydrothermal method on a glass substrate. The influences of varying Co doping in structural, morphological and optical properties were investigated by X-Ray Diffractometer (XRD), Scanning Electron Microscopy (SEM), and UV-Visible (UV-Vis) spectrometry, respectively. All the nanorods exhibit polycrystalline wurtzite structure with smaller crystalline size on the Co-doped nanorods. The nanorods also show no orientation alignment and random particle size. Interestingly, the nanorods with 3 wt.% Co doped shows high absorbance at UV and visible region indicating that optical properties of the ZnO nanorods have been modified by Co doping.

  10. Aloe vera plant-extracted solution hydrothermal synthesis and magnetic properties of magnetite (Fe3O4) nanoparticles

    Science.gov (United States)

    Phumying, Santi; Labuayai, Sarawuth; Thomas, Chunpen; Amornkitbamrung, Vittaya; Swatsitang, Ekaphan; Maensiri, Santi

    2013-06-01

    Magnetite (Fe3O4) nanoparticles have been successfully synthesized by a novel hydrothermal method using ferric acetylacetonate (Fe(C5H8O2)3) and aloe vera plant-extracted solution. The influences of different reaction temperatures and times on the structure and magnetic properties of the synthesized Fe3O4 nanoparticles were investigated. The synthesized nanoparticles are crystalline and have particle sizes of ˜6-30 nm, as revealed by transmission electron microscopy (TEM). The results of X-ray diffraction (XRD), High resolution TEM (HRTEM) and selected area electron diffraction (SAED) indicate that the synthesized Fe3O4 nanoparticles have the inverse cubic spinel structure without the presence of any other phase impurities. The hysteresis loops of the Fe3O4 nanoparticles at room temperature show superparamagnetic behavior and the saturation magnetization of the Fe3O4 samples increases with increasing reaction temperature and time.

  11. Hydrothermal Synthesis and Structure of a New 3D Lanthanide—Carboxylate Framework,[La(btec)1/2(H2btec)1/2(H2O)]n(H4btec=1,2,4,5—Benzeneteracarboxylic acid)

    Institute of Scientific and Technical Information of China (English)

    孙道峰; 毕文华; 曹荣; 李星; 时茜; 洪茂椿

    2003-01-01

    The title complex,[La(baec)1/2(H2btec)1/2(H2O)]n(H4btec=1,2,4,5-benzenetetracarboxylic acid)(1)was synthesized by the hydrothermal reaction of 1,2,4,5-benzenetetracarboxylic dianhydride with La(NO3)3·6H2O in H2O,and crystallizes in the triclinic system,space group P-1 with α=0.64403(3)nm,b=0.94500(4)nm,c=0.96380(5)nm,α=88.535(2)°,β=100.314(2)°,γ=76.6470(10)°,V=1.69968(10)nm3,Z=2,and final R=0.0274,Rw=0.0735.In1,each La(Ⅲ)ion is coordinated by eight oxygen atoms from six carboxylate groups and one coordinated water molecule.Two different coordinstion modes of H4btec were Present in the structure,one of which contains two protonated carboxylate grougps to balance the charge.

  12. Hydrothermal synthesis and characterization of hybrid Al/ZnO-GO composite for significant photodegrdation of dyes

    Science.gov (United States)

    Lellala, Kashinath; Namratha, K.; Sudhakar, K.; Byrappa, K.

    2016-05-01

    In the present work, undoped and doped Aluminum/Zinc Oxide - graphene oxide (Al/ZnO-GO) nanocomposite have been successfully synthesized by hydrothermal method from zinc acetate and aluminum nitrate solutions without using of any surfactant/stabilizing agents. The results show that the composites of GO nanosheets are decorated densely by Al/ZnO nanoparticles, which displays a good morphology and blend between GO and Al/ZnO. Hybrid composites exhibit an enhanced photocatalytic performance in reduction of dyes under UV-Vis radiation better than bare ZnO-GO and GO for methylene blue dye. The hydrothermal method leads to particles with a higher crystalline due to ambient temperature of the reaction and autogenously pressure conditions, which alters the phases and crystallizations of the nanocomposite. The optical band gap is narrowed to lower energy values due to controlled addition of aluminum and GO in the composite. The improved optical property in Al-doped ZnO flower decorated on GO can be attributed to the decrease in oxygen deficiency after Al doping. XRD, FTIR, UV-Vis spectroscopy, Raman, and Field Emission Scanning Electron Microscopy characterized the effects of Al doping on the structural characteristics and optical properties on the ZnO-GO.

  13. Synthesis of zinc aluminate with high surface area by microwave hydrothermal method applied in the transesterification of soybean oil (biodiesel)

    Energy Technology Data Exchange (ETDEWEB)

    Quirino, M.R. [Chemistry Laboratory of Federal University of Paraiba (LABQUIM), Campus III, 58200-000 Bananeiras, PB (Brazil); Oliveira, M.J.C. [Academic Unit of Materials Engineering, UFCG, Campina Grande Campus I, 58429-900 Campina Grande, PB (Brazil); Keyson, D. [Laboratory of study in Science, DME, Federal University of Paraíba, Campus I, 58051-900 João Pessoa, PB (Brazil); Lucena, G.L., E-mail: guilherme_leo1@yahoo.com.br [Chemistry Laboratory of Federal University of Paraiba (LABQUIM), Campus III, 58200-000 Bananeiras, PB (Brazil); Oliveira, J.B.L. [Federal University of Rio Grande do Norte, UFRN, Campus I, 59078-970 Natal, RN (Brazil); Gama, L. [Academic Unit of Materials Engineering, UFCG, Campina Grande Campus I, 58429-900 Campina Grande, PB (Brazil)

    2016-02-15

    Highlights: • ZnAl{sub 2}O{sub 4} spinel was synthesized by the microwave hydrothermal method in only 15 or 30 min. • The powders show high specific surface area. • ZAT{sub b}15 showed activity of 52.22% for the conversion of soybean oil into biodiesel. - Abstract: Zinc aluminate is a material with high thermal stability and high mechanical strength that, owing to these properties, is used as a catalyst or support. In this work, zinc aluminate spinel was synthesized by the microwave hydrothermal method in only 15 or 30 min at a low temperature (150 °C) without templates, using only Al(NO{sub 3}){sub 3}·9H{sub 2}O, Zn(NO{sub 3}){sub 2}·6H{sub 2}O, and urea as precursors and applied in the transesterification of soybean oil. X-ray diffraction analysis showed that ZnAl{sub 2}O{sub 4} had a cubic structure without secondary phases. The nitrogen adsorption measurements (BET) revealed a high surface area (266.57 m{sup 2} g{sup −1}) for the nanopowder synthesized in 15 min. This powder showed activity of 52.22% for the catalytic conversion of soybean oil into biodiesel by transesterification.

  14. Hydrothermal synthesis and characterization of hybrid Al/ZnO-GO composite for significant photodegrdation of dyes

    Energy Technology Data Exchange (ETDEWEB)

    Lellala, Kashinath; Namratha, K.; Byrappa, K., E-mail: kashinathlellala@gmail.com, E-mail: kbyrappa@gmail.com [Centre for Materials Science and Technology, University of Mysore, Vijnana Bhavan, P.B.No.21, Manasagangothri, Mysore - 570006, India. (India); Sudhakar, K. [Lal Bhadur College, S.V.N. Road, Mulugu X-road, Kakatiya University, Warangal-560001, India. (India)

    2016-05-06

    In the present work, undoped and doped Aluminum/Zinc Oxide - graphene oxide (Al/ZnO-GO) nanocomposite have been successfully synthesized by hydrothermal method from zinc acetate and aluminum nitrate solutions without using of any surfactant/stabilizing agents. The results show that the composites of GO nanosheets are decorated densely by Al/ZnO nanoparticles, which displays a good morphology and blend between GO and Al/ZnO. Hybrid composites exhibit an enhanced photocatalytic performance in reduction of dyes under UV-Vis radiation better than bare ZnO-GO and GO for methylene blue dye. The hydrothermal method leads to particles with a higher crystalline due to ambient temperature of the reaction and autogenously pressure conditions, which alters the phases and crystallizations of the nanocomposite. The optical band gap is narrowed to lower energy values due to controlled addition of aluminum and GO in the composite. The improved optical property in Al-doped ZnO flower decorated on GO can be attributed to the decrease in oxygen deficiency after Al doping. XRD, FTIR, UV-Vis spectroscopy, Raman, and Field Emission Scanning Electron Microscopy characterized the effects of Al doping on the structural characteristics and optical properties on the ZnO-GO.

  15. The process of fly ash magnetic separation impact on hydrothermal synthesis of zeolites

    Directory of Open Access Journals (Sweden)

    Czuma Natalia

    2016-01-01

    Full Text Available The aim of the experiment was modifying raw fly ash through the demagnetisation process and determining its influence on the efficiency of the synthesis of zeolite materials out of fly ash. A series of experiments have been performed on modified samples and, for the purpose of verification, on non-modified fly ash. No direct correlation has been confirmed in relation to synthesis efficiency as well as the type of obtained zeolite material. The research results indicate that the composition of fly ash determines the type of the zeolitic phases obtained. Based on the analysis of experimental data, it was found that the demagnetisation process allows to obtain additional zeolite phases, while there is no direct impact of the process used on the increase of synthesis reaction efficiency.

  16. Structural elucidation of sorghum lignins from an integrated biorefinery process based on hydrothermal and alkaline treatments.

    Science.gov (United States)

    Sun, Shao-Long; Wen, Jia-Long; Ma, Ming-Guo; Sun, Run-Cang

    2014-08-13

    An integrated process based on hydrothermal pretreatment (HTP) (i.e., 110-230 °C, 0.5-2.0 h) and alkaline post-treatment (2% NaOH at 90 °C for 2.0 h) has been performed for the production of xylooligosaccharide, lignin, and digestible substrate from sweet sorghum stems. The yield, purity, dissociation mechanisms, structural features, and structural transformations of alkali lignins obtained from the integrated process were investigated. It was found that the HTP process facilitated the subsequent alkaline delignification, releasing lignin with the highest yield (79.3%) and purity from the HTP residue obtained at 190 °C for 0.5 h. All of the results indicated that the cleavage of the β-O-4 linkages and degradation of β-β and β-5 linkages occurred under the harsh HTP conditions. Depolymerization and condensation reactions simultaneously occurred at higher temperatures (≥ 170 °C). Moreover, the thermostability of lignin was positively related to its molecular weight, but was also affected by the inherent structures, such as β-O-4 linkages and condensed units. These findings will enhance the understanding of structural transformations of the lignins during the integrated process and maximize the potential utilizations of the lignins in a current biorefinery process.

  17. Microwave-assisted hydrothermal synthesis of Ag₂(W(1-x)Mox)O₄ heterostructures: Nucleation of Ag, morphology, and photoluminescence properties.

    Science.gov (United States)

    Silva, M D P; Gonçalves, R F; Nogueira, I C; Longo, V M; Mondoni, L; Moron, M G; Santana, Y V; Longo, E

    2016-01-15

    Ag2W(1-x)MoxO4 (x=0.0 and 0.50) powders were synthesized by the co-precipitation (drop-by-drop) method and processed using a microwave-assisted hydrothermal method. We report the real-time in situ formation and growth of Ag filaments on the Ag2W(1-x)MoxO4 crystals using an accelerated electron beam under high vacuum. Various techniques were used to evaluate the influence of the network-former substitution on the structural and optical properties, including photoluminescence (PL) emission, of these materials. X-ray diffraction results confirmed the phases obtained by the synthesis methods. Raman spectroscopy revealed significant changes in local order-disorder as a function of the network-former substitution. Field-emission scanning electron microscopy was used to determine the shape as well as dimensions of the Ag2W(1-x)MoxO4 heterostructures. The PL spectra showed that the PL-emission intensities of Ag2W(1-x)MoxO4 were greater than those of pure Ag2WO4, probably because of the increase of intermediary energy levels within the band gap of the Ag2W(1-x)MoxO4 heterostructures, as evidenced by the decrease in the band-gap values measured by ultraviolet-visible spectroscopy.

  18. Synthesis of barium titanate crystalline nanoparticles using hydrothermal microwave method; Obtencao de nanoparticulas cristalinas de titanato de bario usando metodo hidrotermal assistido por microondas

    Energy Technology Data Exchange (ETDEWEB)

    Souza, A.E.; Silva, R.A.; Teixeira, S.R. [Universidade Estadual Paulista (DFQB/FCT/UNESP), Presidente Prudente, SP (Brazil). Dept. de Fisica, Quimica e Biologia. Lab. de Compositos e Ceramicas Funcionais; Moreira, M.L. [Universidade Federal de Sao Carlos (LiEC/UFSCAR), SP (Brazil). Lab. Interdisciplinar de Eletroquimica e Ceramica; Volanti, D.P.; Longo, E. [Universidade Estadual Paulista (LiEC/UNESP), Araraquara, SP (Brazil). Lab. Interdisciplinar de Eletroquimica e Ceramica

    2009-07-01

    The hydrothermal microwave method (HTMW) was used in the synthesis of barium titanate (BaTiO{sub 3}) nanoparticles. The solution was prepared in deionized water by using titanium (IV) isopropoxide (C{sub 12}H{sub 28}O{sub 4}Ti), barium chloride (BaCl{sub 2}.2H{sub 2}O) and potassium hydroxide (KOH). Afterwards it was heated in an adapted conventional microwave oven. The system is composed of a temperature controller with thermocouple, a hermetic camera of reaction made of teflon, a manometer and a safety valve. The solution was heated to 140 deg C, at a 140 deg C/min heating rate, and maintained at this temperature for 40 minutes. The obtained ceramic powder was characterized by using X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). The XRD data confirms the formation of a high crystalline ceramic material with perovskite structure. The FE-SEM images reveal morphologies with dimensions varying from 27 to 54 nm. (author)

  19. PEG-assisted hydrothermal synthesis of CoFe2O4 nanoparticles with enhanced selective adsorption properties for different dyes

    Science.gov (United States)

    Wu, Xiaofei; Wang, Wei; Li, Feng; Khaimanov, Spartak; Tsidaeva, Natalia; Lahoubi, Mahieddine

    2016-12-01

    Cobalt ferrite nanoparticles (CFO NPs) are synthesized by a facile and polyethylene glycol (PEG) assisted hydrothermal method. In the synthesis of cobalt ferrites, PEG is used as a surfactant. The formation of single-phase spinel structure in the samples is confirmed by XRD patterns. TEM images show that the addition of PEG results in the decrease in the size of the CFO NPs. When the amount of PEG is lower than 2.4 g, the particle sizes decrease, then, further increasing the concentration of PEG in the solution, the particle sizes begin to increase, for much more PEG will cover onto the surface of the nanoparticles. Here, the existence of PEG on the surface of CFO NPs is confirmed from the characteristic bands of PEG in FTIR spectra. All the samples are ferromagnetic, and their saturation magnetization (Ms) decreases with the increase in PEG concentration. The as-synthesized samples show highly selective adsorption characteristics for organic dyes. Compared with methyl orange (MO) and methyl blue (MB) dyes, good adsorption performance of the PEG/CoFe2O4 nanocomposites for Congo red (CR) dye is presented. Moreover, the addition of PEG greatly enhances their adsorption capacity (qe) for CR. The corresponding adsorption behavior fits well with the pseudo-second-order kinetic model and the Langmuir model. And the adsorption mechanism is investigated. This study suggests that the as-prepared products can be regarded as an excellent selective adsorbent to remove dyes from the wastewater.

  20. Hydrothermal synthesis of size-controllable Yttrium Orthovanadate (YVO{sub 4}) nanoparticles and its application in photocatalytic degradation of direct blue dye

    Energy Technology Data Exchange (ETDEWEB)

    Mohamed, R.M., E-mail: redama123@yahoo.com [Chemistry Department, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Advanced Materials Department, Central Metallurgical R and D Institute, CMRDI, P.O. Box 87, Helwan, Cairo 11421 (Egypt); Harraz, F.A. [Advanced Materials Department, Central Metallurgical R and D Institute, CMRDI, P.O. Box 87, Helwan, Cairo 11421 (Egypt); Mkhalid, I.A. [Chemistry Department, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia)

    2012-08-15

    Graphical abstract: XRD patterns of YVO{sub 4} nanopowders prepared at different hydrothermal times; where Y{sub 1} = 4 h, Y{sub 2} = 8 h, Y{sub 3} = 12 h and Y{sub 4} = 24 h. Highlights: Black-Right-Pointing-Pointer Size control of Yttrium Orthovanadate. Black-Right-Pointing-Pointer Hydrothermal synthesis. Black-Right-Pointing-Pointer Removal of direct blue dye. - Abstract: Sized-controlled YVO{sub 4} nanoparticles have been synthesized by a simple hydrothermal method by changing hydrothermal time from 4 to 24 h. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), specific surface area (Brunauer-Emmett-Teller (BET)), and ultraviolet-visible spectroscopy (UV-vis) measurements. The results showed that the size of as-synthesized YVO{sub 4} nanoparticles was in the range of 11-40 nm and was extremely dependent on the hydrothermal time. Photocatalytic measurement showed that the YVO{sub 4} nanoparticles with particle size of about 11 nm (prepared by 4 h hydrothermal time) possess superior photocatalytic properties in the decolorization of direct blue dye. Due to simple preparation, high photocatalytic oxidation of direct blue dye and low cost, the YVO{sub 4} photocatalyst is a potential candidate for pollutants removal and will find wide application in the coming future in photocatalytic oxidation processes. The overall kinetics of photodegradation of direct blue dye using YVO{sub 4} nanopowders photocatalyst was found to be of first order. The photocatalyst could be easily removed from the reaction mixture and its recyclability with no loss of activity was possible for six times. The catalytic performance was found to decrease by 5% after run number six.