WorldWideScience

Sample records for facile hydrothermal method

  1. 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.

  2. Enhanced Photocatalytic Activity of BiOBr/ZnO Heterojunction Semiconductors Prepared by Facile Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Xiangchao Meng

    2015-01-01

    Full Text Available Hexagonal wurtzite pure ZnO and BiOBr-ZnO composites were synthesized by facile hydrothermal method. The amount of BiOBr as dopant was adjusted from 5 wt.% to 75 wt.%, and correspondingly the morphologies and crystal structures of the as-prepared composites were measured and discussed. Specifically, according to XRD patterns and SEM images, the main crystalline structure of ZnO was not destroyed after doping, but growth of ZnO crystals was inhibited by doping BiOBr. Meanwhile, the optical properties of the composites were measured by the diffuse reflectance spectra (DRS. The band gap of composites was also calculated using the classical Tauc equation and it was found to be around 3.0 eV. In the test of photocatalytic activation, the ZnO-BiOBr photocatalysts exhibited high photocatalytic efficiencies in the degradation of Rhodamine B (RhB under visible-light irradiation. It was ascribed to not only the small size of crystalline, but also the reduction in the recombination rate of the photogenerated carriers for the enhancement effect of p-n heterojunction. This work sheds light on improving the photocatalytic performance by establishing the heterojunction and contributes to the development of a commercially competitive photocatalyst.

  3. Inorganic Antiflaming Wood Caused by a TiO2-Decorated ZnO Nanorod Arrays Coating Prepared by a Facile Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Hong Zhang

    2016-01-01

    Full Text Available Wood materials with antiflaming capability were successfully fabricated by depositing a TiO2-decorated ZnO nanorod arrays (ZNAs film on wood surface using a facile and one-pot hydrothermal method. The prepared specimens were characterized by scanning electron microscopy (SEM, energy dispersive X-ray analysis (EDXA, and powder X-ray diffraction (XRD. To explore the antiflaming properties, the combustion parameters of the wood treated by TiO2-decorated ZNAs were measured using the cone calorimetry technique compared with the untreated wood. For treated wood, the burning duration was prolonged for 55 s; smoke production rate (SPR and total smoke production (TSP were obviously reduced, especially for the production of CO was almost zero. As a result, thin inorganic film of TiO2-decorated ZNAs had desirable fire resistance, and one-pot hydrothermal method was a feasible method to fabricate nonflammable wood materials.

  4. 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...

  5. Nanocrystalline GaSbO{sub 4} with high surface area prepared via a facile hydrothermal method and its photocatalytic activity study

    Energy Technology Data Exchange (ETDEWEB)

    Fu Yanghe; Xue Hun; Qin Meng; Liu Ping; Fu Xianzhi [Research Institute of Photocatalysis, Fujian Provincial Key Laboratory of Photocatalysis - State Key Laboratory Breeding Base, Fuzhou University, Fuzhou 350002 (China); Li Zhaohui, E-mail: zhaohuili1969@yahoo.com [Research Institute of Photocatalysis, Fujian Provincial Key Laboratory of Photocatalysis - State Key Laboratory Breeding Base, Fuzhou University, Fuzhou 350002 (China)

    2012-05-05

    Graphical abstract: Nanocrystalline GaSbO{sub 4} prepared via a facile hydrothermal method possesses large specific surface area and exhibits photocatalytic activity for the degradations of salicylic acid and acetone. Highlights: Black-Right-Pointing-Pointer Facile hydrothermal method to nanocrystalline GaSbO{sub 4} with large surface area. Black-Right-Pointing-Pointer GaSbO{sub 4} shows photocatalytic activity for the degradations of salicylic acid and acetone. Black-Right-Pointing-Pointer The photocatalytic mechanism of GaSbO{sub 4} was proposed based on the ESR result. - Abstract: Nanocrystalline GaSbO{sub 4} with small particle size and large BET specific area was successfully prepared via a facile hydrothermal method from Sb{sub 2}O{sub 5}. The influence of the reaction pH on the formation of the final product was investigated. The obtained sample was characterized by X-ray diffraction (XRD), N{sub 2}-sorption BET surface area, UV-vis diffuse reflectance spectroscopy (DRS), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM). The photocatalytic activity for the degradations of salicylic acid and acetone over nanocrystalline GaSbO{sub 4} under UV irradiations was for the first time revealed. Based on the electron spin resonance (ESR) result, the reactive species involved in the photocatalytic reaction over nanocrytalline GaSbO{sub 4} are determined to be HO{center_dot} and O{sub 2}{sup -}{center_dot}. The photocatalytic mechanism of GaSbO{sub 4} was proposed.

  6. A facile one-pot hydrothermal method to prepare europium-doped titania hollow phosphors and their sensitized luminescence properties

    Energy Technology Data Exchange (ETDEWEB)

    Feng Xuan; Yang Ling; Zhang Nianchun [Department of Chemistry and Institute of Nanochemistry, Jinan University, 601 Western Huangpu Road, Guangzhou 510632 (China); Liu Yingliang, E-mail: tliuyl@jnu.edu.c [Department of Chemistry and Institute of Nanochemistry, Jinan University, 601 Western Huangpu Road, Guangzhou 510632 (China)

    2010-09-17

    Research highlights: {yields} The strongest emission intensity was observed with TiO{sub 2}:Eu{sub 0.2} hollow spheres and TiO{sub 2}:Eu{sub 0.2} hollow spheres calcining at 550 {sup o}C. Moreover, the strongest excitation of TiO{sub 2}:Eu{sub 0.2} hollow spheres transferred from 400 to 500 {sup o}C and the effective nonradiative energy transfer from the TiO{sub 2} hollow spheres host matrix to Eu{sup 3+} ions crystal field states was realized due to changes of crystalline field in the environment around Eu{sup 3+} ions occupying Ti{sup 4+} sites. The proposed energy transfer mechanism was that UV light is absorbed in the band of TiO{sub 2} hollow spheres crystal and then the energy is relaxed to the defect states of TiO{sub 2} host. The energy can transfer to the crystal states of Eu{sup 3+} ions ({sup 7}F{sub j}, j = 0, 1, 2, 3 and 4), which results in efficient photoluminescence. The fluorescent intensity of TiO{sub 2}:Eu{sub 0.2} hollow spheres was 2.2 times as strong as that of TiO{sub 2}:Eu{sub 0.2} bulk material. - Abstract: Monodisperse europium-activated titania hollow phosphors had been synthesized by a facile one-pot hydrothermal method using carbon spheres as hard templates. Samples were characterized by X-ray powder diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, energy dispersive spectrometer and photoluminescence spectrum. The strongest emission intensity was observed with TiO{sub 2}:Eu{sub 0.2} hollow spheres and TiO{sub 2}:Eu{sub 0.2} hollow spheres calcining at 550 {sup o}C. Moreover, the strongest excitation of TiO{sub 2}:Eu{sub 0.2} hollow spheres transferred from 400 to 500 {sup o}C and the effective nonradiative energy transfer from the TiO{sub 2} hollow spheres host matrix to Eu{sup 3+} ions crystal field states was realized due to changes of crystalline field in the environment around Eu{sup 3+} ions occupying Ti{sup 4+} sites. The proposed energy transfer mechanism was that UV light is absorbed in the band

  7. Facile Synthesis of N-Doped BiOCl Photocatalyst by an Ethylenediamine-Assisted Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Guihua Chen

    2015-01-01

    Full Text Available 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 BiOCl sample. The N-BiOCl sample exhibited higher photocatalytic activity in the degradation of Rhodamine B under visible light than observed in BiOCl sample, and the stability of the sample was verified. Meanwhile, speculative causes for the enhancement in the photocatalytic activity of N-BiOCl sample were also proposed.

  8. A Facile Low-Temperature Hydrothermal Method to Prepare Anatase Titania/Cellulose Aerogels with Strong Photocatalytic Activities for Rhodamine B and Methyl Orange Degradations

    Directory of Open Access Journals (Sweden)

    Caichao Wan

    2015-01-01

    Full Text Available A facile low-temperature hydrothermal method for in situ preparation of anatase titania (TiO2 homogeneously dispersed in cellulose aerogels substrates was described. The formed anatase TiO2 aggregations composed of a mass of evenly dispersed TiO2 nanoparticles with sizes of 2−5 nm were embedded in the interconnected three-dimensional (3D architecture of the cellulose aerogels matrixes without large-scale reunion phenomenon; meanwhile, the obtained anatase titania/cellulose (ATC aerogels also had a high loading amount of TiO2 (ca. 35.7%. Furthermore, compared with commercially available Degussa P25, ATC aerogels displayed comparable photocatalytic activities for Rhodamine B and methyl orange degradations under UV radiation, which might be useful in the fields of catalysts, wastewater treatment, and organic pollutant degradation. Meanwhile, the photocatalytic reaction behaviors of ATC aerogels under UV irradiation were also illuminated.

  9. Photoelectrochemical characteristics of TiO2 nanorod arrays grown on fluorine doped tin oxide substrates by the facile seeding layer assisted hydrothermal method

    Science.gov (United States)

    Sui, Mei-rong; Han, Cui-ping; Gu, Xiu-quan; Wang, Yong; Tang, Lu; Tang, Hui

    2016-05-01

    TiO2 nanorod arrays (NRAs) were prepared on fluorine doped tin oxide (FTO) substrates by a facile two-step hydrothermal method. The nanorods were selectively grown on the FTO regions which were covered with TiO2 seeding layer. It took 5 h to obtain the compact arrays with the nanorod length of ~2 μm and diameter of ~50 nm. The photoelectrochemical (PEC) properties of TiO2 NRAs are also investigated. It is demonstrated that the TiO2 NRAs indicate the good photoelectric conversion ability with an efficiency of 0.22% at a full-wavelength irradiation. A photocurrent density of 0.21 mA/cm2 is observed at 0.7 V versus the saturated calomel electrode (SCE). More evidences suggest that the charge transferring resistance is lowered at an irradiation, while the flat-band potential ( V fb) is shifted towards the positive side.

  10. 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.

  11. Oxygen vacancy and Ce{sup 3+} ion dependent magnetism of monocrystal CeO{sub 2} nanopoles synthesized by a facile hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Leini [School of Physics and Materials Science, Anhui University, Hefei 230039 (China); Anhui Key Laboratory of Information Materials and Devices, Anhui University, Hefei 230039 (China); Meng, Fanming, E-mail: mrmeng@ahu.edu.cn [School of Physics and Materials Science, Anhui University, Hefei 230039 (China); Anhui Key Laboratory of Information Materials and Devices, Anhui University, Hefei 230039 (China); Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024 (China)

    2013-09-01

    Graphical abstract: - Highlights: • Monocrystal CeO{sub 2} nanopoles are synthesized by hydrothermal method. • Suitable reaction time is beneficial for the growth CeO{sub 2} nanopoles. • As-synthesized CeO{sub 2} nanopoles show excellent RTFM. • The RTFM can be attributed to the influences of oxygen vacancies and Ce{sup 3+} ions. - Abstract: Monocrystal CeO{sub 2} nanopoles of 15–25 nm in diameter and 300–900 nm or more in length were synthesized within 100 h using hydrothermal method with CeCl{sub 3}·7H{sub 2}O as cerium source, NaOH as mineralizer, and ethylenediamine as complexant. The results of XRD and SADE analysis indicate that the as-synthesized CeO{sub 2} samples have the fluorite structure. The band gaps of CeO{sub 2} samples are 0.08–0.38 eV smaller than that of bulk CeO{sub 2}. X-ray photoelectron spectroscopy shows that the concentration of Ce{sup 3+} is higher than 20% for CeO{sub 2} samples. All the as-synthesized CeO{sub 2} samples exhibit the room temperature ferromagnetism (RTFM), and the saturation magnetization (M{sub s}) gradually increases with the increase of E{sub g} up to 2.92 eV and then decreases with E{sub g} increasing more. The highest M{sub s} of 0.167 emu/g is obtained from the CeO{sub 2} nanopoles synthesized within 100 h. The RTFM mechanism of CeO{sub 2} nanopoles has been proposed which can be mainly attributed to the influence of oxygen vacancies and Ce{sup 3+} ions.

  12. Facile one-step fabrication of magnetite particles under mild hydrothermal conditions

    Energy Technology Data Exchange (ETDEWEB)

    Keerthana, D. Shanthini; Namratha, K. [Centre for Materials Science and Technology, Vijnana Bhavan, University of Mysore, Manasagangothri, Mysore 6 (India); Byrappa, K., E-mail: kbyrappa@gmail.com [Centre for Materials Science and Technology, Vijnana Bhavan, University of Mysore, Manasagangothri, Mysore 6 (India); Yathirajan, H.S. [Centre for Materials Science and Technology, Vijnana Bhavan, University of Mysore, Manasagangothri, Mysore 6 (India); DOS in Chemistry, University of Mysore, Manasagangothri, Mysore 6 (India)

    2015-03-15

    Hydrophilic magnetite particles for biological applications were synthesized by hydrothermal method in the presence of D-Glucose as both reducing and capping agent in a facile, one-step, low energy and environmentally friendly route. The role of D-Glucose as a reducing agent in the formation of magnetite particles under mild hydrothermal conditions has been investigated. The absence of D-Glucose results in the formation of hematite. The magnetite particles synthesized were characterized using powder X-ray Diffraction (XRD), Fourier Transform Infrared (FTIR) Spectroscopy, High Resolution Scanning Electron Microscopy (HR-SEM), Dynamic Light Scattering (DLS) and Vibrating Sample Magnetometery (VSM). The influence of the quantity of D-Glucose used and the reaction duration on the formation of magnetite were studied. DLS and HR-SEM results show that the size of the particles was in nano- to micron range. The antioxidant potency of the particles was confirmed using DPPH assay, where 2,2- Diphenyl-1-picrylhydrazyl was used as a source of free radicals. Hence the magnetite particles obtained could be considered for the use in various biological applications. - Highlights: • Magnetite and hematite particles were synthesized using hydrothermal route. • The reactants and experimental parameters were optimized to get single phase magnetite particles. • The role of D-Glucose as a reducing and capping agent is discussed. • The magnetite particles showed very good free radical scavenging ability. • The authors report a simple, facile, one-step method using hydrated ferric salt as a single iron precursor.

  13. Hydrothermal method for preparing calcium phosphate monoliths

    Directory of Open Access Journals (Sweden)

    García Carrodeguas Raúl

    2003-01-01

    Full Text Available A new hydrothermal route for preparing biphasic calcium phosphate monoliths is proposed. Firstly, a slurry of beta-tricalcium phosphate/ortho-phosphoric acid (b-TCP/H3PO4 is cast into the desired final shape and size to obtain a block composed of dicalcium phosphate dihydrate (DCPD and b-TCP. This block is then treated in 1.0 M Na2HPO4 at 60 °C in order to hydrolyze the DCPD into Ca10-x(HPO4x(PO4 6-x(OH2-x (CDHA and Ca8H2(PO46 .5H2O (OCP. The result is a monolithic piece which preserves the initial shape and size, but which is composed instead of CDHA, OCP, and b-TCP. During the initial stage, when the pH is slightly alkaline, the product of DCPD hydrolysis is CDHA. However, when a neutral or slightly acidic pH is reached OCP is formed. Test samples processed by this method showed complete conversion of DCPD into CDHA and OCP after 112 h of hydrolysis, and with a compressive strength of 16.2 MPa, similar to cancellous bone.

  14. Facile hydrothermal preparation of niobium pentaoxide decorated reduced graphene oxide nanocomposites for supercapacitor applications

    Science.gov (United States)

    Murugan, M.; Kumar, R. Mohan; Alsalme, Ali; Alghamdi, Abdulaziz; Jayavel, R.

    2016-04-01

    Facile synthesis of graphene-Nb2O5 composite has been reported. Graphene oxide was prepared by the modified Hummer's method. The metal oxide (Nb2O5) was introduced to the graphene to form the composite by the hydrothermal method. The prepared samples were characterized by X-ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy, Fourier transform infrared (FTIR) and thermo gravimetric analysis (TGA). SEM and TEM results revealed that the metal oxide particles are uniformly dispersed on the surface of thin sheets of well-defined multilayered graphene structure. Thermal stability of the graphene metal oxide nanocomposites was also investigated. The CV measurements reveal a significant enhancement in the specific capacitance reaching 321 Fg-1 at a scan rate of 10 mV s-1. With promising electrochemical characteristics, Nb2O5 decorated graphene nanocomposite are explored as potential electrode material for supercapacitor applications.

  15. 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.

  16. 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.

  17. 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.

  18. Piezoelectric Materials Synthesized by the Hydrothermal Method and Their Applications

    Directory of Open Access Journals (Sweden)

    Takeshi Morita

    2010-12-01

    Full Text Available Synthesis by the hydrothermal method has various advantages, including low reaction temperature, three-dimensional substrate availability, and automatic polarization alignment during the process. In this review, powder synthesis, the fabrication of piezoelectric thin films, and their applications are introduced. A polycrystalline lead zirconate titanate (PZT thin film was applied to a micro ultrasonic motor, and an epitaxial lead titanate (PbTiO3 thin film was estimated as a ferroelectric data storage medium. Ferroelectric and piezoelectric properties were successfully obtained for epitaxial PbTiO3 films. As lead-free piezoelectric powders, KNbO3 and NaNbO3 powders were synthesized by the hydrothermal method and sintered together to form (K,NaNbO3 ceramics, from which reasonable piezoelectric performance was achieved.

  19. A facile hydrothermal approach for construction of carbon coating on TiO2 nanoparticles

    OpenAIRE

    Olurode, Kehinde; Neelgund, Gururaj M.; Oki, Aderemi; Luo, Zhiphing

    2011-01-01

    Herein a facile hydrothermal approach is used to construct carbon coated TiO2 nanoparticles employing dextrose as the source of carbon. The procedure is operated at a low temperature of 200 °C. Fourier infrared spectroscopy demonstrated the successful coating of carbon on TiO2 nanoparticles. The phase composition of TiO2 and carbon coated TiO2 nanoparticles were studied using X-ray diffraction and the surface morphology was analyzed by scanning and transmission electron microscopy. The existe...

  20. Facile Hydrothermal Approach to ZnO Nanorods at Mild Temperature

    Directory of Open Access Journals (Sweden)

    Yang Jiao

    2013-01-01

    Full Text Available In this work, ZnO nanorods are obtained through a facile hydrothermal route. The structure and morphology of the resultant products are characterized by X-ray diffraction (XRD and scanning electron microscope (SEM. The experimental results indicated that the as-synthesized ZnO nanorods have an average diameter of approximate 100 nm. A possible growth mechanism for ZnO nanorods was proposed based on the experimental results and found that Zn powder plays a critical role for the morphology of the products. Room temperature photoluminescence property of ZnO nanorods shows an ultraviolet emission peak at 390 nm.

  1. Hydrothermal analysis in engineering using control volume finite element method

    CERN Document Server

    Sheikholeslami, Mohsen

    2015-01-01

    Control volume finite element methods (CVFEM) bridge the gap between finite difference and finite element methods, using the advantages of both methods for simulation of multi-physics problems in complex geometries. In Hydrothermal Analysis in Engineering Using Control Volume Finite Element Method, CVFEM is covered in detail and applied to key areas of thermal engineering. Examples, exercises, and extensive references are used to show the use of the technique to model key engineering problems such as heat transfer in nanofluids (to enhance performance and compactness of energy systems),

  2. 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.

  3. Facile hydrothermal growth graphene/ZnO nanocomposite for development of enhanced biosensor

    Energy Technology Data Exchange (ETDEWEB)

    Low, Sze Shin [Department of Electrical and Electronic Engineering, Faculty of Engineering, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor (Malaysia); Division of Materials, Mechanics and Structures, Center of Nanotechnology and Advanced Materials, Faculty of Engineering, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor (Malaysia); Tan, Michelle T.T., E-mail: Michelle.Tan@nottingham.edu.my [Department of Electrical and Electronic Engineering, Faculty of Engineering, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor (Malaysia); Division of Materials, Mechanics and Structures, Center of Nanotechnology and Advanced Materials, Faculty of Engineering, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor (Malaysia); Loh, Hwei-San [School of Biosciences, Faculty of Science, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor (Malaysia); Biotechnology Research Centre, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor (Malaysia); Khiew, Poi Sim [Division of Materials, Mechanics and Structures, Center of Nanotechnology and Advanced Materials, Faculty of Engineering, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor (Malaysia); Chiu, Wee Siong [Low Dimensional Materials Research Center, Department of Physics, Faculty of Science, University Malaya, 50603 Kuala Lumpur (Malaysia)

    2016-01-15

    Graphene/zinc oxide nanocomposite was synthesised via a facile, green and efficient approach consisted of novel liquid phase exfoliation and solvothermal growth for sensing application. Highly pristine graphene was synthesised through mild sonication treatment of graphite in a mixture of ethanol and water at an optimum ratio. The X-ray diffractometry (XRD) affirmed the hydrothermal growth of pure zinc oxide nanoparticles from zinc nitrate hexahydrate precursor. The as-prepared graphene/zinc oxide (G/ZnO) nanocomposite was characterised comprehensively to evaluate its morphology, crystallinity, composition and purity. All results clearly indicate that zinc oxide particles were homogenously distributed on graphene sheets, without any severe aggregation. The electrochemical performance of graphene/zinc oxide nanocomposite-modified screen-printed carbon electrode (SPCE) was evaluated using cyclic voltammetry (CV) and amperometry analysis. The resulting electrode exhibited excellent electrocatalytic activity towards the reduction of hydrogen peroxide (H{sub 2}O{sub 2}) in a linear range of 1–15 mM with a correlation coefficient of 0.9977. The sensitivity of the graphene/zinc oxide nanocomposite-modified hydrogen peroxide sensor was 3.2580 μAmM{sup −1} with a limit of detection of 7.4357 μM. An electrochemical DNA sensor platform was then fabricated for the detection of Avian Influenza H5 gene based on graphene/zinc oxide nanocomposite. The results obtained from amperometry study indicate that the graphene/zinc oxide nanocomposite-enhanced electrochemical DNA biosensor is significantly more sensitive (P < 0.05) and efficient than the conventional agarose gel electrophoresis. - Highlights: • One step, green and facile exfoliation of graphite in ethanol/water mixture. • G/ZnO nanocomposite prepared via simple, green low temperature solvothermal method. • CV and amperometric study of G/ZnO nanocomposite towards H{sub 2}O{sub 2} with R{sup 2} of 0.9977.

  4. Multiperiod hydrothermal economic dispatch by an interior point method

    Directory of Open Access Journals (Sweden)

    Kimball L. M.

    2002-01-01

    Full Text Available This paper presents an interior point algorithm to solve the multiperiod hydrothermal economic dispatch (HTED. The multiperiod HTED is a large scale nonlinear programming problem. Various optimization methods have been applied to the multiperiod HTED, but most neglect important network characteristics or require decomposition into thermal and hydro subproblems. The algorithm described here exploits the special bordered block diagonal structure and sparsity of the Newton system for the first order necessary conditions to result in a fast efficient algorithm that can account for all network aspects. Applying this new algorithm challenges a conventional method for the use of available hydro resources known as the peak shaving heuristic.

  5. 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.

  6. Controlled growth of well-aligned ZnO nanowire arrays using the improved hydrothermal method

    Institute of Scientific and Technical Information of China (English)

    Han Zhitao; Li Sisi; Chu Jinkui; Chen Yong

    2013-01-01

    Well-aligned ZnO nanowires were hydrothermally synthesized based on a facile method for preparing the ZnO seed layer which was derived from the combination of a sol-gel process and the spin-coating technique.The effect of the contents of growth solution and the growth duration on the morphology ofZnO nanowires has been investigated.The results indicated that long and vertically aligned ZnO nanowires could be obtained by adjusting the contents of ammonia and polyethyleneimine (PEI) in the growth solution.Under the optimized condition,the length of ZnO nanowires increased fast and almost linearly with the growth duration.After 10 h incubation,ZnO nanowires more than 25μm in length were obtained.By combining the conventional photolithographic method with this hydrothermal approach,long and well-aligned ZnO nanowire arrays were selectively grown on the substrate.In addition,the bottom fusion at the foot of the nanowires has been obviously improved.The results demonstrated that the improved hydrothermal process is favorable to synthesize long and well-aligned ZnO nanowires,and possesses good process compatibility with the conventional photolithographic technique for preparing ZnO nanowire arrays.So it has great potential in applications such as display and field emission devices.

  7. Evaluation methods for hospital facilities

    DEFF Research Database (Denmark)

    Fronczek-Munter, Aneta

    2013-01-01

    Initial position & background: There are various methods and tools for evaluating facilities. The focus is usually on the technical building performance, function/usability or form/beauty. Examples are: Post-Occupancy Evaluation (POE) and Usability Appraisal. Nevertheless, evaluations of buildings...... according to focus areas and proposes which evaluation methods to use in different building phases of healthcare facilities. Hospital evaluations with experts and users are also considered; their subjective view on space, function, technology, usability and aesthetics. Results & solutions: This paper...... of creating buildings with enhanced usability. Additionally various evaluation methods used in hospital cases in Denmark and Norway are presented. Involvement of users is proposed, not just in defining requirements but also in co-creation/design and evaluation of solutions. The theories and preliminary...

  8. A data processing method for MAPR hydrothermal plume tur-bidity data and its application in the Precious Stone Mountain hydrothermal field

    Institute of Scientific and Technical Information of China (English)

    CHEN Sheng; TAO Chunhui; LI Huaiming; CHEN Yongshun; ZHOU Jianping; WU Tao

    2014-01-01

    Hydrothermal plume is an important constituent of seabed hydrothermal circulation and is also one of the characteristics of active hydrothermal vents. Portable Miniature Autonomous Plume Recorders (MAPR) attached to a towed deep-sea instrument was used to search for hydrothermal plumes and hydrothermal vents. We introduced the basic principle of MAPR based on deep towing technology to detect plumes, then analyzed the factors affecting the quality of the MAPR data and presented a data correction method for MAPR, including instrument location correction, noise reduction processing, system error elimination and seawater background reduction. Finally we applied the method to analyze MAPR data obtained during the Chinese DY115-21 cruise on R/VDayang Iin the “Precious Stone Mountain” hydrothermal field on the Gala-pagos Microplate. The results provided a better understanding of the distribution of the hydrothermal activ-ity in this field, indicating the presence of a new hydrothermal vent.

  9. A facile one-pot hydrothermal method to produce SnS2/reduced graphene oxide with flake-on-sheet structures and their application in the removal of dyes from aqueous solution.

    Science.gov (United States)

    Bian, Xiujie; Lu, Xiaofeng; Xue, Yanpeng; Zhang, Chengcheng; Kong, Lirong; Wang, Ce

    2013-09-15

    In this article, we report a novel one-pot synthesis of SnS2/reduced graphene oxide (rGO) flake-on-sheet nanocomposites via in situ reduction of graphene oxide (GO) by Sn(2+) under hydrothermal conditions. The morphology and structure of the obtained product were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction instrument (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The adsorption characteristics of the SnS2/rGO nanocomposites were examined using an organic dye Rhodamine B (RhB) as adsorbate. SnS2/rGO exhibited superior adsorption behavior for RhB. The adsorption kinetics and adsorption isotherm were investigated. The adsorption of RhB by SnS2/rGO was well fitted to the Langmuir isotherm model, and the resultant kinetic data were well described by pseudo-second-order model.

  10. Preparation of thermally stable nanocrystalline hydroxyapatite by hydrothermal method.

    Science.gov (United States)

    Prakash Parthiban, S; Elayaraja, K; Girija, E K; Yokogawa, Y; Kesavamoorthy, R; Palanichamy, M; Asokan, K; Narayana Kalkura, S

    2009-12-01

    Thermally stable hydroxyapatite (HAp) was synthesized by hydrothermal method in the presence of malic acid. X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FT-IR), Raman spectroscopy, scanning electron microscopy (SEM), differential thermal analysis (DTA), thermogravimetric analysis (TGA) was done on the synthesized powders. These analyses confirmed the sample to be free from impurities and other phases of calcium phosphates, and were of rhombus morphology along with nanosized particles. IR and Raman analyses indicated the adsorption of malic acid on HAp. Thermal stability of the synthesized HAp was confirmed by DTA and TGA. The synthesized powders were thermally stable upto 1,400 degrees C and showed no phase change. The proposed method might be useful for producing thermally stable HAp which is a necessity for high temperature coating applications.

  11. 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...

  12. Fabrication of Mineralized Collagen from Bovine Waste Materials by Hydrothermal Method as Promised Biomaterials

    DEFF Research Database (Denmark)

    Sheikh, Faheem A.; Kanjwal, Muzafar Ahmed; Macossay, Javier

    2011-01-01

    In the present study, we aimed to produce mineralized-collagen by hydrothermal process. A simple method not depending on additional foreign chemicals has been employed to isolate the mineralized-collagen fibers from bovine waste. The process of extraction involves the use of hydrothermal method...

  13. Facile hydrothermal method synthesis of coralline-like Li{sub 1.2}Mn{sub 0.54}Ni{sub 0.13}Co{sub 0.13}O{sub 2} hierarchical architectures as superior cathode materials for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Xianhua [Laboratory of Quantum Engineering and Quantum Materials, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006 (China); Engineering Research Center of Materials and Technology for Electrochemical Energy Storage (Ministry of Education), Guangzhou 510006 (China); Huang, Yanling, E-mail: yanling3963@126.com [Laboratory of Quantum Engineering and Quantum Materials, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006 (China); Engineering Research Center of Materials and Technology for Electrochemical Energy Storage (Ministry of Education), Guangzhou 510006 (China); Ma, Shaomeng; Zou, Xiaoli; Hu, Shejun [Laboratory of Quantum Engineering and Quantum Materials, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006 (China); Engineering Research Center of Materials and Technology for Electrochemical Energy Storage (Ministry of Education), Guangzhou 510006 (China); Wu, Yuping [Institute of Advanced Materials, Nanjing University of Technology, Nanjing 210009 (China)

    2015-03-15

    Highlights: • A coralline-like Li{sub 1.20}Mn{sub 0.54}Ni{sub 0.13}Co{sub 0.13}O{sub 2} cathode was synthesized by hydrothermal method. • Initial discharge capacity of 250.2 mAh g{sup −1} for the cathode was obtained at 0.1 C. • A high reversible specific capacity of 210.2 mAh g{sup −1} after 100 cycles was acquired. • The high capacity retention of 84.5% was obtained even after 200 cycles at 10 C. - Abstract: A coralline-like lithium-rich layered cathode material with homogeneous composition of Li{sub 1.20}Mn{sub 0.54}Ni{sub 0.13}Co{sub 0.13}O{sub 2} has been successfully synthesized via a facile ethanolamine (EA)-mediated hydrothermal method route, with subsequent calcination at 850 °C. An initial specific discharge capacity of 250.2 mAh g{sup −1} and a reversible specific capacity of 210.2 mAh g{sup −1} after 100 cycles at a constant density of 25 mA g{sup −1} (1 C = 250 mA g{sup −1}) are acquired. Even at 10 C, it still delivers a discharge capacity of approximately 100 mA h g{sup −1}, thereby indicating its excellent high power performance. The sample also shows enhanced cycling performance with 88.5%, 79.9% and 90.5% of capacity retention after 100 cycles at 0.5, 5 and 10 C rates, respectively. Besides, 84.5% of initial capacity is retained even after 200 cycles at 10 C. Consequently, the fascinating electrochemical performance may facilitate the coralline-like LMNCO composite to be a promising alternative cathode for LIBs with a high application potential.

  14. 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.

  15. 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.

  16. The Facile Hydrothermal Preparation of Orthorhombic WO3 With (001) Facet and Its Photocatalytic Performance.

    Science.gov (United States)

    Deng, Xiaoyan; Dou, Jinbiao; Li, Fenfen; Gao, Hongtao; Liu, Guangjun

    2015-12-01

    The orthorhombic WO3 nanoplates with (001) facet were fabricated via a facile hydrothermal process, using HBF4 as the acid source. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) and UV-vis diffused reflectance spectroscopy (DRS), respectively. It indicated that the obtained product was orthorhombic WO3 (JCPDS No. 20-1324). And the energy gap was estimated to be 2.52 eV by the intersection point of the tangent of the absorption edge and the baseline. It was affirmed that WO3 crystalline grew along the (001) direction, indicating the product was exposed with (001) facet. The photocatalytic activity of (001) WO3 nanoplates was investigated on the degradation of Rhodamine B (RhB). It demonstrated that photocatalysts exhibited obvious photocatalytic performance under visible light irradiation. The degradation rate of RhB with the typical product reached 95% after being irradiated for 5 h. It indicated that the photocatalytic efficiency of WO3 could be improved by controlling the crystal growth and its morphology.

  17. Optimization of process condition of nanosilica production by hydrothermal method

    Science.gov (United States)

    Qisti, N.; Indrasti, N. S.; Suprihatin

    2016-11-01

    Bagasse ashes have high silica content thus it can be used in nanosilicaproduction to increase its benefit value. This study aimed to get the best time for synthesis and to determine the optimum synthesis time and temperature. This study used the hydrothermal method, a simple method with relatively low reaction temperature and provide a good chemical homogeneity. Time varieties in synthesizing silica were 8,10 and 12 hours, at the temperature of 150 °C. But the results were not as expected. Moreover, optimization of synthesis temperature and time used 4 hours at the temperature of 150 °C based on previous studies. Optimization was conducted using the Response Surface Methodology (RSM). Later, a testusing PSA (Particle Size Analyzer) was performed to obtain particle sizes and PDI values (Polydispersity Index). The results showed that the prediction model of temperature synthesis was 152.67 °C synthesis time of 6 hours, particle size of 276.288 nm and PDI value of 0.189642. The tests showed that the size of particle obtained was 330.39 nm and PDI value at 0.3580. Actual results and predicted results were not significant different.

  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. Effects of pH and temperature on photocatalytic activity of PbTiO3 synthesized by hydrothermal method

    Science.gov (United States)

    Li, Yongyu; Sun, Haijie; Wang, Ning; Fang, Wenxue; Li, Zhongjun

    2014-11-01

    PbTiO3 photocatalyst was synthesized successfully by facile hydrothermal method. The effects of the hydrothermal reaction temperatures and the pH values of the systems on the photocatalytic activities of PbTiO3 were investigated in detail. The photocatalytic activities of samples were evaluated by the degradation of methyl orange (MO) aqueous solution under simulated solar irradiation. The as-obtained PbTiO3 sample exhibits anisotropical growth along the (0 0 1) plane, and its photocatalytic activity is about 3 times higher than that of PbTiO3 prepared by precipitation method. Moreover, the as-prepared PbTiO3 has high stability during photocatalytic oxidation process, and does not cause secondary pollution.

  20. Magnetic ferrites synthesised using the microwave-hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Melo, R.S.; Silva, F.C.; Moura, K.R.M. [Department of Chemistry, Federal University of Maranhão, Campus of Bacanga, São Luís 65080-805 (Brazil); Menezes, A.S. de [Department of Physics, Federal University of Maranhão, Campus of Bacanga, São Luís 65080-805 (Brazil); Sinfrônio, F.S.M., E-mail: kjvida@mac.com [Department of Electrical Engineering, Federal University of Maranhão, Campus of Bacanga, São Luís 65080-805 (Brazil)

    2015-05-01

    Ceramic spinel-based ferrites of Cobalt, Nickel, Copper and Zinc were prepared using the hydrothermal method assisted with microwave. All samples were characterised using EDS, WDXRF, XRD, SEM, FTIR, Raman and VSM techniques. The structural, compositional, phonic and magnetic properties indicate that the evaluated method can produce magnetic materials. The EDS and WDXRF analyses suggest the materialisation of Co{sub 1.0}Fe{sub 2.0}O{sub 4}, Ni{sub 0.9}Fe{sub 2.1}O{sub 4}, Cu{sub 1.1}Fe{sub 1.9}O{sub 4} and Zn{sub 1.1}Fe{sub 1.9}O{sub 4} ferrites. XRD measurements indicate the formation of monophasic Cobalt, Nickel and Zinc cubic inverse-spinel-based structures, whereas Cooper ferrite was structured as body-centred tetragonal distorted inverse-spinel and cubic phase, which was contaminated with monoclinic CuO. The estimated average crystallite sizes using Rietveld refinement were approximately 163 nm (Co{sub 1.0}Fe{sub 2.0}O{sub 4}), 187 nm (Ni{sub 0.9}Fe{sub 2.1}O{sub 4}), 21 nm (Cu{sub 1.1}Fe{sub 1.9}O{sub 4}) and 226 nm (Zn{sub 1.1}Fe{sub 1.9}O{sub 4}). Infrared spectra exhibit characteristic modes at approximately 574–581 cm{sup −1} [ν(Co–O)]{sub Td}, 568–603 cm{sup −1} [ν(N–O)]{sub Td}, 607–661 cm{sup −1} [ν(Cu–O)]{sub Td} and 578–598 cm{sup −1} [ν(Zn–O)]{sub Td}. The Raman spectra for Co{sub 1.0}Fe{sub 2.0}O{sub 4} exhibit vibrational modes at 172 (T{sub 2g}), 304 (E{sub g}) 460 (A{sub 1g}) and 620–680 cm{sup −1} (A{sub 1g}), whereas Ni{sub 0.9}Fe{sub 2.1}O{sub 4} exhibits T{sub 2g} (477 cm{sup −1}) A{sub 1g} (690 cm{sup −1}) modes. Cu{sub 1.1}Fe{sub 1.9}O{sub 4} shows vibrational modes at approximately 148 (F{sub 2g}), 447 (F{sub 2g}), 552 (F{sub 2g}) and 671 cm{sup −1} (A{sub 1g}), and Zn{sub 1.1}Fe{sub 1.9}O{sub 4} has another four distinct modes at approximately 248, 348, 486 and 651, which are assigned to E{sub g}, T{sub 2g} and A{sub 1g} symmetries. Several obtained ferrites exhibit soft magnetisation with

  1. 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.

  2. Facile hydrothermal growth graphene/ZnO nanocomposite for development of enhanced biosensor.

    Science.gov (United States)

    Low, Sze Shin; Tan, Michelle T T; Loh, Hwei-San; Khiew, Poi Sim; Chiu, Wee Siong

    2016-01-15

    Graphene/zinc oxide nanocomposite was synthesised via a facile, green and efficient approach consisted of novel liquid phase exfoliation and solvothermal growth for sensing application. Highly pristine graphene was synthesised through mild sonication treatment of graphite in a mixture of ethanol and water at an optimum ratio. The X-ray diffractometry (XRD) affirmed the hydrothermal growth of pure zinc oxide nanoparticles from zinc nitrate hexahydrate precursor. The as-prepared graphene/zinc oxide (G/ZnO) nanocomposite was characterised comprehensively to evaluate its morphology, crystallinity, composition and purity. All results clearly indicate that zinc oxide particles were homogenously distributed on graphene sheets, without any severe aggregation. The electrochemical performance of graphene/zinc oxide nanocomposite-modified screen-printed carbon electrode (SPCE) was evaluated using cyclic voltammetry (CV) and amperometry analysis. The resulting electrode exhibited excellent electrocatalytic activity towards the reduction of hydrogen peroxide (H2O2) in a linear range of 1-15 mM with a correlation coefficient of 0.9977. The sensitivity of the graphene/zinc oxide nanocomposite-modified hydrogen peroxide sensor was 3.2580 μAmM(-1) with a limit of detection of 7.4357 μM. An electrochemical DNA sensor platform was then fabricated for the detection of Avian Influenza H5 gene based on graphene/zinc oxide nanocomposite. The results obtained from amperometry study indicate that the graphene/zinc oxide nanocomposite-enhanced electrochemical DNA biosensor is significantly more sensitive (P < 0.05) and efficient than the conventional agarose gel electrophoresis.

  3. A Novel Eco-Friendly Vanadium Precipitation Method by Hydrothermal Hydrogen Reduction Technology

    Directory of Open Access Journals (Sweden)

    Guobin Zhang

    2017-09-01

    Full Text Available In view of the serious pollution problems caused by the traditional vanadium precipitation process, the eco-friendly technology of hydrothermal hydrogen reduction was first applied to precipitate phase pure vanadium sesquioxide (V2O3 products from stripped pentavalent vanadium (V (V solution extracted from vanadium-bearing shale. Thermodynamic analysis demonstrate the method of hydrothermal hydrogen reduction is feasible for precipitating V2O3 from V (V solution at a suitable pH range, and the reduction should better be carried out at a lower pH under the pH range in which V2O3 can exist stably. The V2O3 products of 99.92% in purity and a high vanadium precipitation percentage of 99.25% were achieved under a facile reaction condition of initial solution pH of 6, reaction temperature of 523 K, H2 partial pressure of 4 MPa and reaction time of 2 h. Based on the analysis of XRD and FE-SEM with EDS for the precipitation products obtained at serial reaction times, the phase transformation mechanism was summarized to serial reductions with the phase transformation of HxVyOz(2z−x−5y− → NaV2O5 → VO2(H2O0.5 → VOOH → V2O3. Compared with the two-step traditional method of precipitating vanadium with ammonium salt and roast-reduction (react at above 773 K for more than 3 h for preparing V2O3, this method only experiences one-step reduction under a green atmosphere of H2 gas with a lower reaction temperature of 523 K and a shorter reaction time of 2h. Therefore, this method for vanadium precipitation is characterized by being eco-friendly, having a short process and being low-energy consumption, which has great significance for the sustainable development of vanadium industry.

  4. 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.

  5. Synthesis of Graphene-CdSe Composite by a Simple Hydrothermal Method and Its Photocatalytic Degradation of Organic Dyes

    Institute of Scientific and Technical Information of China (English)

    OH Won-Chun; CHEN Mingliang; CHO Kwangyoun; KIM Cheolkyu; MENG Zeda; ZHULei

    2011-01-01

    A graphene-CdSe composite was synthesized by a facile hydrothermal method,and characterized by X-ray diffiraction,scanning electron microscopy with energy dispersive X-ray analysis,transmission electron microscopy and UV-vis diffuse reflectance spectrophotometry.The graphene-CdSe composite efficiently catalyzed the photodegradation of methylene blue (MB),methyl orange (MO) and rhodamine B (Rh.B) in aqueous solution under UV or visible light irradiation.The graphene-CdSe composite exhibited a higher photocatalytic activity for the MB solution.

  6. 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.)

  7. 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.

  8. Methods and apparatus for catalytic hydrothermal gasification of biomass

    Science.gov (United States)

    Elliott, Douglas C.; Butner, Robert Scott; Neuenschwander, Gary G.; Zacher, Alan H.; Hart, Todd R.

    2012-08-14

    Continuous processing of wet biomass feedstock by catalytic hydrothermal gasification must address catalyst fouling and poisoning. One solution can involve heating the wet biomass with a heating unit to a temperature sufficient for organic constituents in the feedstock to decompose, for precipitates of inorganic wastes to form, for preheating the wet feedstock in preparation for subsequent separation of sulfur contaminants, or combinations thereof. Treatment further includes separating the precipitates out of the wet feedstock, removing sulfur contaminants, or both using a solids separation unit and a sulfur separation unit, respectively. Having removed much of the inorganic wastes and the sulfur that can cause poisoning and fouling, the wet biomass feedstock can be exposed to the heterogeneous catalyst for gasification.

  9. Application of Hyperspectral Methods in Hydrothermal Mineral System Studies

    Science.gov (United States)

    Laukamp, Carsten; Cudahy, Thomas; Gessner, Klaus; Haest, Maarten; Cacetta, Mike; Rodger, Andrew; Jones, Mal; Thomas, Matilda

    2010-05-01

    hyperspectral mineral mapping of contaminating, carbonate- or clay-rich zones helped to better constrain the ore zones and the genesis of the mineral system. Airborne hyperspectral data covering about 2500 km2 were obtained from the Eastern Goldfields Superterrane (Yilgarn Craton, Western Australia), which is highly prospective for Archean Au as well as komatiite associated Fe-Ni sulphide mineralisation. In this project hyperspectral airborne data allowed not only the remote mapping of mafic and ultramafic rocks, which are among the main host rocks for Archean Au deposits in the study area, but also the remote mapping of hydrothermal alteration patterns and various geochemical signatures related to the structurally controlled Au mineralisation down to a 4.5 m pixel size. We can reconstruct fluid pathways and their intersections with steep physicochemical gradients, where Au deposition presumably took place, by combining hyperspectral remote sensing with hyperspectral drill core data in 3D mineral maps. White mica mineral maps as well as mineral maps based on the abundance and composition of MgOH and FeOH bearing silicates are the main products for a semi-quantitative assessment of the key alteration minerals in this project. In the southern Selwyn Range, Mount Isa Inlier, Queensland, hyperspectral mineral maps, such as "ferric oxide abundance", "white mica abundance" and "white mica composition", were integrated with geophysical datasets (total magnetic intensity, ternary radiometric imagery). The integration of the datasets enabled us to construct a comprehensive fluid flow model contributing to our understanding of iron-oxide Cu-Au deposits in this region, identifying the source, pathway and depositional sites, which are in good accordance with known deposits. 3D mineral maps derived from hyperspectral methods can distinctly improve our understanding of mineral systems. The advantages of hyperspectral techniques over conventional exploration methods include: (1) the fast and

  10. Dye-Sensitized Solar Cells with Anatase TiO2 Nanorods Prepared by Hydrothermal Method

    OpenAIRE

    Ming-Jer Jeng; Yi-Lun Wung; Liann-Be Chang; Lee Chow

    2013-01-01

    The hydrothermal method provides an effective reaction environment for the synthesis of nanocrystalline materials with high purity and well-controlled crystallinity. In this work, we started with various sizes of commercial TiO2 powders and used the hydrothermal method to prepare TiO2 thin films. We found that the synthesized TiO2 nanorods were thin and long when smaller TiO2 particles were used, while larger TiO2 particles produced thicker and shorter nanorods. We also found that TiO2 films ...

  11. Graphene oxide assisted facile hydrothermal synthesis of LiMn0.6Fe0.4PO4 nanoparticles as cathode material for lithium ion battery

    Institute of Scientific and Technical Information of China (English)

    Changchang Xu; Li Li; Fangyuan Qiu; Cuihua An; Yanan Xu; Ying Wang; Yijing Wang; Lifang Jiao; Huatang Yuan

    2014-01-01

    Assisted by graphene oxide (GO), nano-sized LiMn0.6Fe0.4PO4 with excellent electrochemical performance was prepared by a facile hy-drothermal method as cathode material for lithium ion battery. SEM and TEM images indicate that the particle size of LiMn0.6Fe0.4PO4 (S2) was about 80 nm in diameter. The discharge capacity of LiMn0.6Fe0.4PO4 nanoparticles was 140.3 mAh·g-1 in the first cycle. It showed that graphene oxide was able to restrict the growth of LiMn0.6Fe0.4PO4 and it in situ reduction of GO could improve the electrical conductivity of LiMn0.6Fe0.4PO4 material.

  12. Preparation and characterization of WO3 from ammonium paratungstate via hydrothermal method

    Institute of Scientific and Technical Information of China (English)

    Li Xiancai; Cao Xiaohua; Wang Wenjuan; Yang Yifeng; Rao Guohua

    2006-01-01

    Tungsten trioxide powder has been prepared from ammonium paratungstate via hydrothermal method using orthogonal and mono-level design of experiments.The effects of preparation process on particle size,specific surface area,crystal form and crystalline morphology of the tungsten trioxide was investigated by TEM and XRD etc.It was found that the optimum conditions of the preparation are hydrothermal crystallization for 8 h at 180℃,followed by vacuum drying at 45℃ and calcination at 500℃ for 2 h.The blank reference experiment shows that hydrothermal crystallization treatment favors the formation of hexagonal tungsten trioxide,and the tungsten trioxide powder sample prepared by this method has a high degree of crystallinity.

  13. 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.

  14. Facile hydrothermal preparation of recyclable S-doped graphene sponge for Cu{sup 2+} adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Lianqin; Yu, Baowei [College of Chemistry and Environment Protection Engineering, Southwest University for Nationalities, Chengdu 610041 (China); Xue, Fumin [Shandong Provincial Analysis and Tester Center, Shandong Academy of Science, Jinan 250014 (China); Xie, Jingru; Zhang, Xiaoliang; Wu, Ruihan; Wang, Ruijue; Hu, Zhiyan [College of Chemistry and Environment Protection Engineering, Southwest University for Nationalities, Chengdu 610041 (China); Yang, Sheng-Tao, E-mail: yangst@pku.edu.cn [College of Chemistry and Environment Protection Engineering, Southwest University for Nationalities, Chengdu 610041 (China); Luo, Jianbin, E-mail: luojb1971@163.com [College of Chemistry and Environment Protection Engineering, Southwest University for Nationalities, Chengdu 610041 (China)

    2015-04-09

    Graphical abstract: S-doped graphene sponge was prepared via hydrothermal treatment, where S-doped graphene sponge had an adsorption capacity of 228 mg/g for Cu{sup 2+}. - Highlights: • S-doped graphene sponge was prepared by hydrothermal treatment for heavy metal adsorption. • S-doped graphene sponge had a huge adsorption capacity for Cu{sup 2+}, which was 40 times higher than that of active carbon. • S-doped graphene sponge could be easily regenerated by washing with acidic thiourea. - Abstract: Graphene sponge (GS) has been widely employed for water purification, but adsorption capacity loss frequently occurs during the formation of spongy structure. In this study, we reported the hydrothermal preparation of S-doped GS for the removal of Cu{sup 2+} with a huge adsorption capacity of 228 mg/g, 40 times higher than that of active carbon. The adsorption isotherm could be well fitted into the Freundlich model with a K{sub F} value of 36.309 (L/mg){sup 1/n}. The equilibrium adsorption could be fully achieved in the first 5 min. In the thermodynamics study, the negative ΔG indicated that the adsorption was spontaneous and physisorption in nature. The positive ΔH implied that the adsorption was endothermic. The changes of both pH and ionic strength had no apparent influence on the adsorption. S-doped GS could be easily regenerated by washing with acidic thiourea. Moreover, S-doped GS could be used for the adsorption of other heavy metal ions, too. The implication to the applications of S-doped GS in water treatment is discussed.

  15. 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.

  16. Study on Modification of Ultra-Stable Zeolite Prepared by Hydrothermal Method

    Institute of Scientific and Technical Information of China (English)

    Zhang Weilin; Zhou Lingping; Shen Shimin; Li Zheng; Zhu Yuxia; Tian Huiping; Long Jun

    2007-01-01

    The ultra-stable zeolite DASY-0.0 was prepared by hydrothermal method in commercial scale.Its structure was further modified via the treatment for cleaning of pores(CP).The zeolite samples before and after CP treating were analyzed and characterized by XRF,XRD,NMR,IR,BET and DTA.The results showed that,in comparison with the conventional ultra-stable zeolite DASY-0.0 prepared by the hydrothermal process,the CP-modified zeolite SOY0 exhibited a higher relative crystallinity.a larger surface area and pore volume,a higher thermal stability and contained less amorphous non-framework Al.

  17. A Facile Synthetic Method for Biphenyltetracarboxylic Dianhydrides

    Institute of Scientific and Technical Information of China (English)

    Xue E WU; Chang Lu GAO; Meng Xian DING; Suo Bo ZHANG; Lian Xun GAO

    2004-01-01

    We report a facile and high-yielding procedure for preparing biphenyltetracarboxylic dianhydrides (BPDAs). This method relies on a nickel-catalyzed electroreductive coupling reaction of dimethyl 3-chorophthalate (3-DMCP) and/or dimethyl 4-chorophthalate (4-DMCP) with subsequent hydrolysis of tetra-ester and dehydration of tetra-acid.

  18. 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).

  19. Selective hydrothermal method to create patterned and photoelectrochemically effective Pt/WO3 Interfaces

    NARCIS (Netherlands)

    Zoontjes, Michel G.C.; Huijben, Mark; Baltrusaitis, Jonas; Wiel, van der Wilfred G.; Mul, Guido

    2013-01-01

    A hydrothermal method based on the use of hydrogen peroxide is described to grow a homogeneous layer of tungsten oxide (WO3) on a platinum (Pt) film supported on a silicon wafer. WO3 growth is highly selective for Pt when present on silicon in a patterned arrangement, demonstrating that Pt catalyzes

  20. Optical characteristics of ZnO single crystal grown by the hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Chen, G. Z.; Yin, J. G., E-mail: gzhchen@siom.ac.cn, E-mail: yjg@siom.ac.cn; Zhang, L. H.; Zhang, P. X.; Wang, X. Y.; Liu, Y. C. [Chinese Academy of Sciences, Key Laboratory of High Power Laser Materials, Shanghai Institute of Optics and Fine Mechanics (China); Zhang, C. L. [Guilin Research Institute of Geology for Mineral Resources (China); Gu, S. L. [Nanjing University, Department of Physics (China); Hang, Y., E-mail: yhang@siom.ac.cn [Chinese Academy of Sciences, Key Laboratory of High Power Laser Materials, Shanghai Institute of Optics and Fine Mechanics (China)

    2015-12-15

    ZnO single crystals have been grown by the hydrothermal method. Raman scattering and Photoluminescence spectroscopy (PL) have been used to study samples of ZnO that were unannealed or annealed in different ambient gases. It is suggested that the green emission may originate from defects related to copper in our samples.

  1. Facile hydrothermal preparation of titanium dioxide decorated reduced graphene oxide nanocomposite

    Science.gov (United States)

    Chang, Betty Yea Sze; Huang, Nay Ming; An’amt, Mohd Nor; Marlinda, Abdul Rahman; Norazriena, Yusoff; Muhamad, Muhamad Rasat; Harrison, Ian; Lim, Hong Ngee; Chia, Chin Hua

    2012-01-01

    A simple single-stage approach, based on the hydrothermal technique, has been introduced to synthesize reduced graphene oxide/titanium dioxide nanocomposites. The titanium dioxide nanoparticles are formed at the same time as the graphene oxide is reduced to graphene. The triethanolamine used in the process has two roles. It acts as a reducing agent for the graphene oxide as well as a capping agent, allowing the formation of titanium dioxide nanoparticles with a narrow size distribution (~20 nm). Transmission electron micrographs show that the nanoparticles are uniformly distributed on the reduced graphene oxide nanosheet. Thermogravimetric analysis shows the nanocomposites have an enhanced thermal stability over the original components. The potential applications for this technology were demonstrated by the use of a reduced graphene oxide/titanium dioxide nanocomposite-modified glassy carbon electrode, which enhanced the electrochemical performance compared to a conventional glassy carbon electrode when interacting with mercury(II) ions in potassium chloride electrolyte. PMID:22848166

  2. Facile hydrothermal preparation of titanium dioxide decorated reduced graphene oxide nanocomposite

    Directory of Open Access Journals (Sweden)

    Chang BYS

    2012-07-01

    Full Text Available Betty Yea Sze Chang,1 Nay Ming Huang,1 Mohd Nor An' amt,2 Abdul Rahman Marlinda,1 Yusoff Norazriena,1 Muhamad Rasat Muhamad,3 Ian Harrison,4 Hong Ngee Lim,5 Chin Hua Chia61Low Dimensional Materials Research Center, Physics Department, University of Malaya, Kuala Lumpur; 2Faculty of Agro Industry and Natural Resources (FASA, Universiti Malaysia Kelantan, Kota Bharu, Kelantan; 3The Chancellery Building, Multimedia University, Persiaran Multimedia, Cyberjaya, Selangor; 4School of Chemical and Environmental Engineering, The University of Nottingham Malaysia Campus, Semenyih, Selangor; 5Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, Serdang, Selangor, Malaysia; 6School of Applied Physics, Universiti Kebangsaan Malaysia, Bangi, Selangor, MalaysiaAbstract: A simple single-stage approach, based on the hydrothermal technique, has been introduced to synthesize reduced graphene oxide/titanium dioxide nanocomposites. The titanium dioxide nanoparticles are formed at the same time as the graphene oxide is reduced to graphene. The triethanolamine used in the process has two roles. It acts as a reducing agent for the graphene oxide as well as a capping agent, allowing the formation of titanium dioxide nanoparticles with a narrow size distribution (~20 nm. Transmission electron micrographs show that the nanoparticles are uniformly distributed on the reduced graphene oxide nanosheet. Thermogravimetric analysis shows the nanocomposites have an enhanced thermal stability over the original components. The potential applications for this technology were demonstrated by the use of a reduced graphene oxide/titanium dioxide nanocomposite-modified glassy carbon electrode, which enhanced the electrochemical performance compared to a conventional glassy carbon electrode when interacting with mercury(II ions in potassium chloride electrolyte.Keywords: graphene oxide, titanium oxide, hydrothermal, nanocomposite

  3. A study of thermal properties of sodium titanate nanotubes synthesized by microwave-assisted hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Preda, Silviu, E-mail: predas01@yahoo.co.uk [Institute of Physical Chemistry “Ilie Murgulescu”, 202 Splaiul Independentei, 060021 Bucharest (Romania); Rutar, Melita [Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); Jožef Stefan International Postgraduate School, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); Umek, Polona [Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); Zaharescu, Maria [Institute of Physical Chemistry “Ilie Murgulescu”, 202 Splaiul Independentei, 060021 Bucharest (Romania)

    2015-11-15

    Highlights: • The microwave-assisted hydrothermal route was used for titanate nanotubes synthesis. • Conversion to single-phase nanotube morphology completes after 8 h reaction time. • The nanotube morphology is stable up to 600 °C, as determined by in-situ XRD and SEM. • Sodium ions migrate to the surface due to thermal motion and structure condensation. - Abstract: Sodium titanate nanotubes (NaTiNTs) were synthesized by microwave-assisted hydrothermal treatment of commercial TiO{sub 2}, at constant temperature (135 °C) and different irradiation times (15 min, 1, 4, 8 and 16 h). The products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, differential scanning calorimetry and specific surface area measurements. The irradiation time turned out to be the key parameter for morphological control of the material. Nanotubes were observed already after 15 min of microwave irradiation. The analyses of the products irradiated for 8 and 16 h confirm the complete transformation of the starting TiO{sub 2} powder to NaTiNTs. The nanotubes are open ended with multi-wall structures, with the average outer diameter of 8 nm and specific surface area up to 210 m{sup 2}/g. The morphology, surface area and crystal structure of the sodium titanate nanotubes synthesized by microwave-assisted hydrothermal method were similar to those obtained by conventional hydrothermal method.

  4. Synthesis of thorn-like Ca2B2O5.H2O by hydrothermal method

    Indian Academy of Sciences (India)

    Guowei Zhao; Laiping Zhang; Jilin Wang; Jie Li; Qiongli Qian; Xinye Pan; Yunle Gu

    2011-10-01

    Thorn-like polycrystalline Ca2B2O5.H2O microspheres with nano-sized slices were synthesized using boric acid and calcium hydroxide as reactants by a facile catalyst-free hydrothermal method at low temperature. The products were characterized by means of X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The XRD pattern reveals that the Ca2B2O5.H2O is a monoclinic phase polycrystalline with cell parameters = 0.6702, = 0.5419 and = 0.3558 nm. SEM also reveals that the monoclinic phase polycrystalline are thornlike microspheres composed of many flakes with an average thickness of <100 nm. Possible reaction and growth mechanism were also discussed.

  5. Payment methods for outpatient care facilities

    Science.gov (United States)

    Yuan, Beibei; He, Li; Meng, Qingyue; Jia, Liying

    2017-01-01

    Background Outpatient care facilities provide a variety of basic healthcare services to individuals who do not require hospitalisation or institutionalisation, and are usually the patient's first contact. The provision of outpatient care contributes to immediate and large gains in health status, and a large portion of total health expenditure goes to outpatient healthcare services. Payment method is one of the most important incentive methods applied by purchasers to guide the performance of outpatient care providers. Objectives To assess the impact of different payment methods on the performance of outpatient care facilities and to analyse the differences in impact of payment methods in different settings. Search methods We searched the Cochrane Central Register of Controlled Trials (CENTRAL), 2016, Issue 3, part of the Cochrane Library (searched 8 March 2016); MEDLINE, OvidSP (searched 8 March 2016); Embase, OvidSP (searched 24 April 2014); PubMed (NCBI) (searched 8 March 2016); Dissertations and Theses Database, ProQuest (searched 8 March 2016); Conference Proceedings Citation Index (ISI Web of Science) (searched 8 March 2016); IDEAS (searched 8 March 2016); EconLit, ProQuest (searched 8 March 2016); POPLINE, K4Health (searched 8 March 2016); China National Knowledge Infrastructure (searched 8 March 2016); Chinese Medicine Premier (searched 8 March 2016); OpenGrey (searched 8 March 2016); ClinicalTrials.gov, US National Institutes of Health (NIH) (searched 8 March 2016); World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (searched 8 March 2016); and the website of the World Bank (searched 8 March 2016). In addition, we searched the reference lists of included studies and carried out a citation search for the included studies via ISI Web of Science to find other potentially relevant studies. We also contacted authors of the main included studies regarding any further published or unpublished work. Selection criteria Randomised

  6. Preparation and Photocatalytic of Nanoneedle Bi/ZnWO₄by Two-Step Hydrothermal Method.

    Science.gov (United States)

    Chen, Haifeng; Guo, Lingmei; Zhang, Dandan; Li, Jingxin; Liu, Shipin; Li, Bin

    2016-01-01

    Nanoneedle Bi/ZnWO₄ photocatalysts were successfully synthesized using a two-step hydrothermal method. In the first hydrothermal experiment ZnO/ZnWO₄ nanoneedle crystals were synthesized from NaWO₄· 2H₂O and Zn(NO₃)₂· 6H₂O, using polyacrylamide (PAM) as a template in a hydrothermal environment. Bi cations were then reduced by t-BuONa in a second hydrothermal experiment, adding nanoneedle ZnO/ZnWO₄. The catalysts were then characterized by powder X-ray diffraction (XRD), scanning electron microcopy (SEM), energy dispersive spectrometer (EDS) and UV-vis diffuse reflectance spectrum (DRS). The results show that by adding Bi nanoparticles, the composition of the mixture gradually changed from that of ZnO/ZnWO₄ to Bi/ZnWO₄. The nanoneedle Bi/ZnWO₄samples displayed better UV light photocatalysis than the nanoneedle ZnO/ZnWO₄ samples. The optimum concentration of Bi was investigated using a photocatalytic experiment. A "blue shift" was observed when the molar ratio of Bi was increased.

  7. 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.

  8. 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.

  9. Facile hydrothermal preparation of recyclable S-doped graphene sponge for Cu2+ adsorption.

    Science.gov (United States)

    Zhao, Lianqin; Yu, Baowei; Xue, Fumin; Xie, Jingru; Zhang, Xiaoliang; Wu, Ruihan; Wang, Ruijue; Hu, Zhiyan; Yang, Sheng-Tao; Luo, Jianbin

    2015-04-09

    Graphene sponge (GS) has been widely employed for water purification, but adsorption capacity loss frequently occurs during the formation of spongy structure. In this study, we reported the hydrothermal preparation of S-doped GS for the removal of Cu(2+) with a huge adsorption capacity of 228 mg/g, 40 times higher than that of active carbon. The adsorption isotherm could be well fitted into the Freundlich model with a KF value of 36.309(L/mg)(1/n). The equilibrium adsorption could be fully achieved in the first 5 min. In the thermodynamics study, the negative ΔG indicated that the adsorption was spontaneous and physisorption in nature. The positive ΔH implied that the adsorption was endothermic. The changes of both pH and ionic strength had no apparent influence on the adsorption. S-doped GS could be easily regenerated by washing with acidic thiourea. Moreover, S-doped GS could be used for the adsorption of other heavy metal ions, too. The implication to the applications of S-doped GS in water treatment is discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. PREPARATION OF MULTI-WALLED CARBON NANOTUBES USING NiO CATALYST SYNTHESIZED BY HYDROTHERMAL METHOD

    Institute of Scientific and Technical Information of China (English)

    Y.J. Zhu; Y.L. Chen; X.M. Xue; Y.M. Chen; C.Y. Wu; T.C. Kuang; S.H. Li; H. Y. Zhang

    2003-01-01

    The Ni(OH)2/SiO2 binary colloid was prepared using Ni(NO3)2.6H2O and (C2H5 O)4SiO4 as starting materials and was used to form NiO/SiO2 composite powder by hydrothermal method and desiccant method in open air respectively. Multiwalled carbon nanotubes (MWCNTs) were synthesized respectively by chemical vapor deposition using the NiO/SiO2 catalyst prepared by different methods. The phase and morphology of the catalysts and the morphology, output yield and purity of MWCNTs were compared by XRD, TEM and SEM. The results show that the catalyst powder prepared by hydrothermal method, compared with that by desiccant method, is smaller, better dispersion and has stronger catalytic activity. Pure MWCNTs with smaller tube diameter and narrow range could be obtained at a high yield using that NiO/SiO.2 powder prepared by hydrothermal method as catalyst.

  11. 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.

  12. Studies on the Properties of ZnO Crystal Plane Grown by the Innovated Hydrothermal Method

    Institute of Scientific and Technical Information of China (English)

    WANG Yong-Hao; CHEN Da-Gui; LI Wei; HUANG Jia-Kui; WANG Guo-Hong; LIN Zhang; HUANG Feng

    2008-01-01

    ZnO single crystals were grown by the innovated hydrothermal method. The crystal surfaces were polished, and then studied by atom force microscope (AFM) and wet-chemical etching (WCE). It was found that the Zn polar plane was smoother than O polar plane under the same polishing conditions. The etch pit density of Zn polar plane is 4.3×103 cm-2,which is consistent with the previous report, while the density of etch pit of O polar plane is more than 103 cm-2. After annealing treatment, the density of etch pit of Zn plane reduces to 5.8×102 cm-2 and is superior to the current report. This investigation reveals that the high quality ZnO single crystals with fine Zn polar plane can be obtained by the innovated hydrothermal method.

  13. Preparation of CdS nanoparticles by hydrothermal method in microemulsion

    Institute of Scientific and Technical Information of China (English)

    ZANG Jinxin; ZHAO Gaoling; HAN Gaorong

    2007-01-01

    CdS nanoparticles with good crystallinity were prepared by hydrothermal method in microemulsion composed of polyoxyethylene laurylether/water/cyclohexane/butanol.The structure and the size of the CdS nanoparticles were analyzed by TEM and XRD.The UV-Vis optical absorption of the samples was also investigated.The results show that hydrothermal treatment is an effective method to prepare CdS nanoparticles of hexagonal structure at lower temperature.The particles were in dimensional uniformity.The diameter of the CdS nanoparticles decreased with the increase of the molar ratio of water to surfactant.The minimum diameter of the CdS nanoparticles prepared in this work was about 10 nm.Obvious blue shift appeared in the UV-Vis absorption spectra.

  14. Facile method for fabrication of surfactant-free concentrated CeO2 sols

    Science.gov (United States)

    Shcherbakov, Alexander B.; Teplonogova, Maria A.; Ivanova, Olga S.; Shekunova, Taisiya O.; Ivonin, Ivan V.; Baranchikov, Alexander Ye; Ivanov, Vladimir K.

    2017-05-01

    We report a facile method for fabrication of highly concentrated electrostatically stabilized colloidal solutions containing ultra-small cerium (IV) oxide crystallites having a narrow size distribution (3-5 nm according to x-ray diffraction, and 10-30 nm according to dynamic light scattering). The proposed method comprises hydrothermal treatment of ceric ammonium nitrate aqueous solutions having concentrations over 0.2 M, in the temperature range of 80-100 °C, and the formation of nanoceria sediments, which can be easily peptized in both protic (water, isopropanol) and aprotic (DMF) media, forming stable and transparent CeO2 sols.

  15. The Optical Properties of Crystalline Zn3Nb2O8 Nanomaterials Obtained by Hydrothermal Method

    OpenAIRE

    Mihaela Birdeanu; Mirela Vaida; Eugenia Fagadar-Cosma

    2015-01-01

    The present study is focused on the obtaining of the Zn3Nb2O8 nanomaterial using the hydrothermal method and its characterization through different techniques. X-ray diffraction at room temperature revealed that a novel crystalline form of the nanomaterial forms at 1100°C belonging to monoclinic space group C2/c. Field-emission scanning electron microscopy evidenced the columnar morphology of the particle’s agglomeration and the high resolution electron transmission microscopy confirms the me...

  16. Effect of Preparation Parameters on Photoactivity of BiVO4 by Hydrothermal Method

    OpenAIRE

    Qingyun Chen; Miao Zhou; Di Ma; Dengwei Jing

    2012-01-01

    Bismuth vanadate (BiVO4) was synthesized from a mixture of aqueous Bi(NO3)3 and NH4VO3 solutions by using hydrothermal method. Via conducting the orthogonal experiments and single-factor experiments, the best synthetic parameters were determined. The physical and photophysical properties of the as-obtained samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and UV-Vis diffusion reflectance spectroscopy (UV-Vis). Th...

  17. A facile growth mechanism, structural, optical, dielectric and electrical properties of ZnSe nanosphere via hydrothermal process

    Science.gov (United States)

    Javed, Qurat-Ul-Ain; Baqi, Sabah; Abbas, Hussain; Bibi, Maryam

    2017-02-01

    Hydrothermal method was chosen as a convenient method to fabricate zinc selenide (ZnSe) nanoparticle materials. The prepared nanospheres were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM), where its different properties were observed using UV-visible spectroscopy and LCR meter. It was found that the pure ZnSe nanoparticles have a Zinc blende structure with crystallite size 10.91 nm and in a spherical form with average diameter of 35 nm (before sonication) and 18 nm (after sonication) with wide band gap of 4.28 eV. It was observed that there is inverse relation of frequency with dielectric constant and dielectric loss while AC conductivity grows up by increasing frequency. Such nanostructures were determined to be effectively used in optoelectronic devices as UV detector and in those devices where high-dielectric constant materials are required.

  18. Dye-Sensitized Solar Cells with Anatase TiO2 Nanorods Prepared by Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Ming-Jer Jeng

    2013-01-01

    Full Text Available The hydrothermal method provides an effective reaction environment for the synthesis of nanocrystalline materials with high purity and well-controlled crystallinity. In this work, we started with various sizes of commercial TiO2 powders and used the hydrothermal method to prepare TiO2 thin films. We found that the synthesized TiO2 nanorods were thin and long when smaller TiO2 particles were used, while larger TiO2 particles produced thicker and shorter nanorods. We also found that TiO2 films prepared by TiO2 nanorods exhibited larger surface roughness than those prepared by the commercial TiO2 particles. It was found that a pure anatase phase of TiO2 nanorods can be obtained from the hydrothermal method. The dye-sensitized solar cells fabricated with TiO2 nanorods exhibited a higher solar efficiency than those fabricated with commercial TiO2 nanoparticles directly. Further, triple-layer structures of TiO2 thin films with different particle sizes were investigated to improve the solar efficiency.

  19. Payment methods for outpatient care facilities.

    Science.gov (United States)

    Yuan, Beibei; He, Li; Meng, Qingyue; Jia, Liying

    2017-03-03

    Outpatient care facilities provide a variety of basic healthcare services to individuals who do not require hospitalisation or institutionalisation, and are usually the patient's first contact. The provision of outpatient care contributes to immediate and large gains in health status, and a large portion of total health expenditure goes to outpatient healthcare services. Payment method is one of the most important incentive methods applied by purchasers to guide the performance of outpatient care providers. To assess the impact of different payment methods on the performance of outpatient care facilities and to analyse the differences in impact of payment methods in different settings. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), 2016, Issue 3, part of the Cochrane Library (searched 8 March 2016); MEDLINE, OvidSP (searched 8 March 2016); Embase, OvidSP (searched 24 April 2014); PubMed (NCBI) (searched 8 March 2016); Dissertations and Theses Database, ProQuest (searched 8 March 2016); Conference Proceedings Citation Index (ISI Web of Science) (searched 8 March 2016); IDEAS (searched 8 March 2016); EconLit, ProQuest (searched 8 March 2016); POPLINE, K4Health (searched 8 March 2016); China National Knowledge Infrastructure (searched 8 March 2016); Chinese Medicine Premier (searched 8 March 2016); OpenGrey (searched 8 March 2016); ClinicalTrials.gov, US National Institutes of Health (NIH) (searched 8 March 2016); World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (searched 8 March 2016); and the website of the World Bank (searched 8 March 2016).In addition, we searched the reference lists of included studies and carried out a citation search for the included studies via ISI Web of Science to find other potentially relevant studies. We also contacted authors of the main included studies regarding any further published or unpublished work. Randomised trials, non-randomised trials, controlled before

  20. Facile Hydrothermal Synthesis of Monodispersed MoS2 Ultrathin Nanosheets Assisted by Ionic Liquid Brij56

    Directory of Open Access Journals (Sweden)

    Guan-Qun Han

    2015-01-01

    Full Text Available Monodispersed MoS2 ultrathin nanosheets have been successfully fabricated by a facile hydrothermal process assisted by ionic liquid Brij56. The effect of Brij56 on the morphology and structure of MoS2 has been obviously observed. XRD shows that the as-prepared MoS2 assisted by Brij56 has the weak and broad peak of (002 planes, which implies the small size and well dispersed structure of MoS2 nanosheets. TEM and SEM images reveal that MoS2 ultrathin nanosheets have small size and few stacking layers with the adding of Brij56. HRTEM images prove that MoS2 appears to have a highly monodispersed morphology and to be monolayer ultrathin nanosheets with the length about 5–8 nm, which can provide more exposed rims and edges as active sites for hydrogen evolution reaction. Brij56 has played a crucial role in preparing monodispersed MoS2 ultrathin nanosheets as excellent electrocatalysts. The growth mechanism of monodispersed MoS2 has been discussed in detail.

  1. Effect of PVP Additive on Properties of Cobalt Ferrite Nanoparticles Prepared by Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    P. Razmjouee

    2015-05-01

    Full Text Available In this investigation, the effect of Polyvinylpyrrolidone (PVP additive on microstructure, morphology and magnetic properties of cobalt ferrite nanoparticles prepared by hydrothermal method was studied. X-ray diffraction (XRD studies in different synthesis conditions showed the formation of cobalt ferrite and cobalt oxide. Comparing IR spectrum of PVP additive, sol prepared before hydrothermal process and C-0.1PVP3, 190 obtained by FTIR spectroscopy indicated the formation of bond between PVP and surface of metallic hydroxide and cobalt ferrite particles, which prevented them from growing and coarsening. Scanning electron microscope (SEM was used to study the morphology of samples. According to vibration sample magnetometer (VSM results, as PVP amount increases from 0.1 to 0.3 volume percent, coercive field increases from 298 to 684 Oe and saturation magnetization decreases from 58 to 51 emu/g.

  2. Preparation of scandia stabilized zirconia powder using microwave-hydrothermal method

    Institute of Scientific and Technical Information of China (English)

    敖红敏; 刘向生; 张赫; 周静; 黄小卫; 冯宗玉; 徐宏

    2015-01-01

    Scandia stabilized zirconia powder (ScSZ) was first synthesized by a microwave-hydrothermal method. The crystalline and aggregated particle sizes were investigated by means of X-ray diffraction (XRD), Raman, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Weakly agglomerated and well crystallized ScSZ powder was prepared by micro-wave-heating to 150 ºC and 2.5 h. The structure of the ScSZ powder changed from a tetragonal to a cubic phase, and accordingly, the powder conductivity was increased from 90.55 to 120.56 ms/cm by the introduction of the mineralizer solutions (KOH+K2CO3) dur-ing the microwave-hydrothermal processing.

  3. BIMORPH-TYPE PIEZOELECTRIC THIN FILM BENDING ACTUATORS SYNTHESIZED BY HYDROTHERMAL METHOD

    Institute of Scientific and Technical Information of China (English)

    Du Liqun; Arai Fumihito; Fukuda Toshio; Kwon Guiryong

    2004-01-01

    Lead zirconate titanium solid-solution (PZT) thin films with various thickness are synthesized on titanium substrates by repeated hydrothermal treatments.Young modulus,electric-field- induced displacement and the density of the PZT film are measured respectively.Bimorph- type bending actuators are fabricated using these films.The model,which is used to analyze the driving ability of bimorph-type bending actuators by hydrothermal method,is set up.It can be seen that the driving ability of bimorph-type bending actuators can be greatly improved by optimizing the thickness of PZT thin film and substrate from the theoretical analysis results.The measured values are expected to agree with the theoretical values calculated by the above model.

  4. Y2O3:Eu nanocrystals as biomarkers prepared by a microwave hydrothermal method

    Science.gov (United States)

    Kaszewski, Jarosław; Godlewski, Michał M.; Witkowski, Bartłomiej S.; Słońska, Anna; Wolska-Kornio, Ewelina; Wachnicki, Łukasz; Przybylińska, Hanka; Kozankiewicz, Bolesław; Szal, Anna; Domino, Małgorzata A.; Mijowska, Ewa; Godlewski, Marek

    2016-09-01

    Microwave hydrothermal growth of Y2O3 crystallites results in needle-shaped aggregates of μm length. Thermal treatment has little influence on the material microstructure, but significant impact on the nanometric level. Nanoparticles doped with europium show an intense red luminescence, related to the 5D0 → 7F2 transition of Eu3+ ions. The luminescence intensity increases with the calcination temperature and is accompanied by increasing size of Y2O3:Eu crystallites. EPR studies show the absence of Eu2+ related signals in the material. Y2O3:Eu nanoparticles crystallized via a microwave hydrothermal method were employed as luminescent biomarkers in mice. The initial tests confirmed their applicability as biological markers. Persorption of the Y2O3:Eu nanoparticles after IG in the adult mouse duodenum, brain and liver is reported.

  5. Fabrication and characterization of nanostructured titanate materials by the hydrothermal treatment method.

    Science.gov (United States)

    Doong, Ruey-an; Kao, I-ling

    2008-01-01

    The synthesis and characterization of one-dimensional (1-D) tubular and fibrous nanostructured materials have recently received highly attention. Various morphologies of 1-D nanostructured titanate materials including nanosheets, nanotubes, nanowires, and nanoribbons have recently been successfully synthesized using the alkaline hydrothermal method. In spite of the controversy of the chemical structures and formation mechanisms, titanate nanostructures have attracted much attention on applications of dye-sensitized solar cell, hydrogen sensing, lithium storage and photocatalysis because of their unique features of high specific surface area, ion-exchange capacity and aspect ratio, and unique optical and electrochemical properties. The morphology and microstructure of titanate nanostructures are highly dependent on the preparation conditions. In this review, we highlight the synthesis of TiO(2)-derived nanomaterials under various hydrothermal conditions. The patents for fabrication of various morphologies of nanostructures are also introduced. Effects of preparation parameters including hydrothermal temperature, duration, alkaline concentration, starting materials, and post-treatment on the morphology and microstructure of titanate nanomaterials are reviewered. In addition, the microwave-assisted method for fabrication of 1-D titanate nanostructures is discussed and compared. The applications of titanate nanomaterials in photocatalysis, ion-exchange, and lithium storages are also introduced.

  6. 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.

  7. 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.

  8. TiO2 Nanowire dye-sensitized solar cells Fabricated by Hydrothermal Method

    Science.gov (United States)

    Xu, Yang; Gu, Haoshuang; Xia, Huating; Hu, Mingzhe

    2011-02-01

    TiO2 nanowire dye-sensitized solar cells were fabricated by using hydrothermal method. The synthesizing of TiO2 nanowire/nanorod arrays directly on FTO substrate would cause a high conducting loss to solar cells. Through la minating a compact layer between FTO substrate and photonic anode layer, the conducting loss could be effectively prevented. Results indicated that using different concentration of titanium tetrabutoxide would affect the photoelectric conversion efficiency and different producing methods of the compact layer also played an important role to the conversion efficiency.

  9. A facile one-pot hydrothermal synthesis of β-MnO2 nanopincers and their catalytic degradation of methylene blue

    Science.gov (United States)

    Cheng, Gao; Yu, Lin; Lin, Ting; Yang, Runnong; Sun, Ming; Lan, Bang; Yang, Lili; Deng, Fangze

    2014-09-01

    Branched β-MnO2 bipods with novel nanopincer morphology were prepared by a facile one-pot hydrothermal method via a redox reaction between NaClO3 and MnSO4 in sulfuric acid solution without using any surfactants or templates. The products were characterized in detail by various techniques including X-ray powder diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, surface area analyzer, field emission scanning electron microscopy and transmission electron microscopy. Results show that the obtained β-MnO2 nanopincers consist of two sharp nanorods with a diameter of 100-200 nm and a length of 1-2 μm. The concentration of H2SO4 solution plays an important role in controlling the crystal phase and morphology of the final product. A possible formation mechanism for the β-MnO2 nanopincers was proposed. Moreover, these β-MnO2 nanostructures exhibited better catalytic performance than the commercial MnO2 particles to decompose methyl blue (MB) in the presence of H2O2.

  10. Preparation of meta-stable phases of barium titanate by Sol-hydrothermal method

    Directory of Open Access Journals (Sweden)

    Mahalakshmi Selvaraj

    2015-11-01

    Full Text Available Two low-cost chemical methods of sol–gel and the hydrothermal process have been strategically combined to fabricate barium titanate (BaTiO3 nanopowders. This method was tested for various synthesis temperatures (100 °C to 250 °C employing barium dichloride (BaCl2 and titanium tetrachloride (TiCl4 as precursors and sodium hydroxide (NaOH as mineralizer for synthesis of BaTiO3 nanopowders. The as-prepared BaTiO3 powders were investigated for structural characteristics using x-ray diffraction (XRD, scanning electron microscopy (SEM and transmission electron microscopy (TEM. The overall analysis indicates that the hydrothermal conditions create a gentle environment to promote the formation of crystalline phase directly from amorphous phase at the very low processing temperatures investigated. XRD analysis showed phase transitions from cubic - tetragonal - orthorhombic - rhombohedral with increasing synthesis temperature and calculated grain sizes were 34 – 38 nm (using the Scherrer formula. SEM and TEM analysis verified that the BaTiO3 nanopowders synthesized by this method were spherical in shape and about 114 - 170 nm in size. The particle distribution in both SEM and TEM shows that as the reaction temperature increases from 100 °C to 250 °C, the particles agglomerate. Selective area electron diffraction (SAED shows that the particles are crystalline in nature. The study shows that choosing suitable precursor and optimizing pressure and temperature; different meta-stable (ferroelectric phases of undoped BaTiO3 nanopowders can be stabilized by the sol-hydrothermal method.

  11. Photocatalytic properties of hierarchical ZnO flowers synthesized by a sucrose-assisted hydrothermal method

    Science.gov (United States)

    Lv, Wei; Wei, Bo; Xu, Lingling; Zhao, Yan; Gao, Hong; Liu, Jia

    2012-10-01

    In this work, hierarchical ZnO flowers were synthesized via a sucrose-assisted urea hydrothermal method. The thermogravimetric analysis/differential thermal analysis (TGA-DTA) and Fourier transform infrared spectra (FTIR) showed that sucrose acted as a complexing agent in the synthesis process and assisted combustion during annealing. Photocatalytic activity was evaluated using the degradation of organic dye methyl orange. The sucrose added ZnO flowers showed improved activity, which was mainly attributed to the better crystallinity as confirmed by X-ray photoelectron spectroscopy (XPS) analysis. The effect of sucrose amount on photocatalytic activity was also studied.

  12. Multiple objective optimization of hydro-thermal systems using Ritz's method

    Directory of Open Access Journals (Sweden)

    L. Bayón Arnáu

    2000-01-01

    Full Text Available This paper examines the applicability of the Ritz method to multi-objective optimization of hydro-thermal systems. The algorithm proposed is aimed to minimize an objective functional that incorporates the cost of energy losses, the conventional fuel cost and the production of atmospheric emissions such as NOx and SO2 caused by the operation of fossil-fueled thermal generation. The formulation includes a general layout of hydro-plants that may form multi-chains of reservoir network.

  13. Preparation of lithium fast ionic conductor by sol-gel-hydrothermal method

    Institute of Scientific and Technical Information of China (English)

    Wang Qinghua; Wang Bengen; Xu Yan; Liu Hongyu

    2006-01-01

    The solid fast ionic conductor was synthesized by the sol-gel-hydrothermal method.The influences of the dispersion reagent,the alkalinity and the calcination temperature on the surface morphology of nanopowders,and the electric conductivity were discussed.When PEG 12000 was used as the dispersion reagent,the alkalinity was 1.0% and the calcination temperature was 550℃; the electric conductivity at ambience temperature of the inorganic nanopowder of lithium fast ionic conductor synthesized was 2.59 ±10-3 S·cm-1.

  14. Growth Mechanism of Different Morphologies of ZnO Crystals Prepared by Hydrothermal Method

    Institute of Scientific and Technical Information of China (English)

    Hu Wang; Juan Xie; Kangping Yan; Ming Duan

    2011-01-01

    Different morphologies of zinc oxide (ZnO), including microrods, hexagonal pyramid-like rods and flower-like rod aggregates, had been synthesized, respectively, on glass substrates by controlling the reaction conditions (such as precursor concentration, reaction time and pH value) of hydrothermal method. The morphologies of the as-obtained ZnO were observed with scanning electron microscopy and transmission electron microscopy. Also, the crystalline natures of different ZnO crystals were analyzed with X-ray diffraction. The possible growth mechanism of ZnO crystals with different morphologies was discussed.

  15. Preparation and Self-assembly of Zirconia Nanoparticles via Hydrothermal Method

    Institute of Scientific and Technical Information of China (English)

    LI Guang-Hui; HONG Zhang-Lian; YANG Hui

    2008-01-01

    Zirconia nanoparticles were synthesized via hydrothermal method without any additives. This work focuses on the effect of preparation conditions such as the precursor preparation condition and crystallization time of nanocrystallite in autoclave on the properties of as-prepared products. The results indicated that the amount of tetragonal zirconia varied with the preparation conditions. It increased with the increase of the concentration of KOH solution in precursor producing process and reduced with the prolongation of crystallization time. At the same time, the particle size and morphology were also affected by the preparation conditions. In addition,the self-assembled spindle- like aggregates were observed in present works.

  16. Boehmite nanostructures preparation by hydrothermal method from anodic aluminium oxide membrane.

    Science.gov (United States)

    Yang, X; Wang, J Y; Pan, H Y

    2009-02-01

    Boehmite nanostructures were successfully synthesized from porous anodic aluminium oxide (AAO) membrane by a simple and efficient hydro-thermal method. The experiment used high purity alumina as raw material, and the whole reaction process avoided superfluous impurities to be introduced. Thus, the purity of Boehmite products was ensured. The examinations of the morphology and structure were carried out by atomic force microscope (AFM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Composition of the specimens was analyzed using energy dispersive X-ray spectroscope (EDX) and X-ray diffraction (XRD). Based on these observations the growth process was analyzed.

  17. Photocatalytic properties of ZnO micromaterials prepared by hydrothermal method

    Science.gov (United States)

    Gao, Junshan; Huang, Shaofu; Luo, Pengfei; Huang, Shuanghe

    2016-12-01

    ZnO microrods were prepared by a simple and inexpensive hydrothermal method. The structure, morphology and optical properties of the micromaterials were characterized by XRD, FE-SEM and UV-Vis spectroscopy. The FE-SEM micrographs indicated that the sizes of the microrods were 0.2-1 μm in width and 2-5 μm in length. With methyl orange as a model degradation target, photocatalytic performance of the microrods under ultraviolet radiation was evaluated. The results indicate that the photocatalytic activity of ZnO microrods was satisfactory even under low power ultraviolet irradiation.

  18. 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

    pharmaceutical, biotechnological and biomedical applications. Discussion Aloe vera extract was processed using a green and facile method. This was a hydrothermal method to reduce silver nitrate to AgNPs@AV. Varying the hydrothermal temperature provided the fine spherical shaped nanoparticles. The size of the nanomaterial was affected by its thermal preparation. The particle size of AgNPs could be tuned by varying both time and temperature. A process using a pure AG phase could go to completion in 6 h at 200 oC, whereas reactions at lower temperatures required longer times. Moreover, the antibacterial effect of this hybrid nanomaterial was sufficient that it could be used to inhibit pathogenic bacteria since silver release was dependent upon its particle size. The high activity of the largest AgNPs might have resulted from a high concentration of aloe vera compounds incorporated into the AgNPs during hydrothermal synthesis.

  19. 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

    utilized in pharmaceutical, biotechnological and biomedical applications. Discussion Aloe vera extract was processed using a green and facile method. This was a hydrothermal method to reduce silver nitrate to AgNPs@AV. Varying the hydrothermal temperature provided the fine spherical shaped nanoparticles. The size of the nanomaterial was affected by its thermal preparation. The particle size of AgNPs could be tuned by varying both time and temperature. A process using a pure AG phase could go to completion in 6 h at 200 oC, whereas reactions at lower temperatures required longer times. Moreover, the antibacterial effect of this hybrid nanomaterial was sufficient that it could be used to inhibit pathogenic bacteria since silver release was dependent upon its particle size. The high activity of the largest AgNPs might have resulted from a high concentration of aloe vera compounds incorporated into the AgNPs during hydrothermal synthesis.

  20. 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

    , biotechnological and biomedical applications. Aloe vera extract was processed using a green and facile method. This was a hydrothermal method to reduce silver nitrate to AgNPs@AV. Varying the hydrothermal temperature provided the fine spherical shaped nanoparticles. The size of the nanomaterial was affected by its thermal preparation. The particle size of AgNPs could be tuned by varying both time and temperature. A process using a pure AG phase could go to completion in 6 h at 200 (o)C, whereas reactions at lower temperatures required longer times. Moreover, the antibacterial effect of this hybrid nanomaterial was sufficient that it could be used to inhibit pathogenic bacteria since silver release was dependent upon its particle size. The high activity of the largest AgNPs might have resulted from a high concentration of aloe vera compounds incorporated into the AgNPs during hydrothermal synthesis.

  1. 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.

  2. 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.

  3. Photoluminescence properties of PZT 52/48 synthesized by microwave hydrothermal method using PVA with template

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, G.F., E-mail: guilmina@hotmail.com [Instituto de Quimica, Universidade Estadual Paulista, Departamento de Bioquimica e Tecnologia Quimica, Rua Francisco Degni s/n, Quitandinha, 14800-900 Araraquara, SP (Brazil); Gasparotto, G. [Instituto de Quimica, Universidade Estadual Paulista, Departamento de Bioquimica e Tecnologia Quimica, Rua Francisco Degni s/n, Quitandinha, 14800-900 Araraquara, SP (Brazil); Paris, E.C. [Empresa Brasileira de Pesquisa Agropecuaria, Embrapa Instrumentacao, Rua XV de novembro, 1452, Centro, 13.569-970 Sao Carlos, SP (Brazil); Zaghete, M.A.; Longo, E.; Varela, J.A. [Instituto de Quimica, Universidade Estadual Paulista, Departamento de Bioquimica e Tecnologia Quimica, Rua Francisco Degni s/n, Quitandinha, 14800-900 Araraquara, SP (Brazil)

    2012-01-15

    Lead Titanate Zirconate (PZT) perovskite powders were synthesized by microwave hydrothermal method (M-H) at 180 {sup o}C for different time periods (2, 4, 8 and 12 h) with the presence of aqueous polyvinyl alcohol (PVA) solution 0.36 g L{sup -1}. The X-Ray diffraction (XRD), SE-FEG as well as the measurements of photoluminescence (PL) emission were used for monitoring the formation of a perovskite phase with random polycrystalline distortion in the structure. Emission spectra with fixed excitation wavelength of 350 nm showed higher value for the powder obtained after undergoing 8 h of treatment. A theoretical model derived from previous calculations allows us to discuss the origin of photoluminescence emission in the powders, which can be further related to the local disorder in the network of both ZrO{sub 6} and TiO{sub 6} octahedral, and dodecahedral PbO{sub 12}. The new morphology initially observed from the PZT perovskite crystal growth bearing the shape of fine plates is found to be directly related to photoluminescence emission with energy lower than that present in the PZT with cube-like morphology that emits in 560 nm. - Highlights: > This work details the efficiency of microwave hydrothermal synthesis in obtaining PZT powders. > PVA is used as a crystallization agent of PZT particles. > PZT particles presented photoluminescent (PL) behavior. > There aren't previous reports of photoluminescent PZT obtained by microwave hydrothermal synthesis. > Photoluminescence is one more interesting property for technological applications this material.

  4. Facile hydrothermal synthesis of TiO2-Bi2WO6 hollow superstructures with excellent photocatalysis and recycle properties.

    Science.gov (United States)

    Hou, Ya-Fei; Liu, Shu-Juan; Zhang, Jing-huai; Cheng, Xiao; Wang, You

    2014-01-21

    One-dimensional mesoporous TiO2-Bi2WO6 hollow superstructures are prepared using a hydrothermal method and their photocatalysis and recycle properties are investigated. Experimental results indicate that anatase TiO2 nanoparticles are coupled with hierarchical Bi2WO6 hollow tubes on their surfaces. The TiO2-Bi2WO6 structure has a mesoporous wall and the pores in the wall are on average 21 nm. The hierarchical TiO2-Bi2WO6 heterostructures exhibit the highest photocatalytic activity in comparison with P25, pure Bi2WO6 hollow tube and mechanical mixture of Bi2WO6 tube and TiO2 nanoparticle in the degradation of rhodamine B (RhB) under simulated sunlight irradiation. The as-prepared TiO2-Bi2WO6 heterostructures can be easily recycled through sedimentation and they retains their high photocatalytic activity during the cycling use in the simulated sunlight-driving photodegradation process of RhB. The prepared mesoporous TiO2-Bi2WO6 with hollow superstructure is therefore a promising candidate material for water decontamination use.

  5. Multiple objective optimization of hydro-thermal systems using Ritz's method

    Directory of Open Access Journals (Sweden)

    Arnáu L. Bayón

    1999-01-01

    Full Text Available This paper examines the applicability of the Ritz method to multi-objective optimization of hydro-thermal systems. The algorithm proposed is aimed to minimize an objective functional that incorporates the cost of energy losses, the conventional fuel cost and the production of atmospheric emissions such as NO x and SO 2 caused by the operation of fossil-fueled thermal generation. The formulation includes a general layout of hydro-plants that may form multi-chains of reservoir network. Time-delays are included and the electric network is considered by using the active power balance equation. The volume of water discharge for each hydro-plant is a given constant amount from the optimization interval. The generic minimization algorithm, which is not difficult to construct on the basis of the Ritz method, has certain advantages in comparison with the conventional methods.

  6. 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...

  7. Nonlinear approximation method in Lagrangian relaxation-based algorithms for hydrothermal scheduling

    Energy Technology Data Exchange (ETDEWEB)

    Guan, X. [Pacific Gas and Electric, San Francisco, CA (United States); Luh, P.B.; Zhang, L. [Univ. of Connecticut, Storrs, CT (United States). Dept. of Electrical and Systems Engineering

    1995-05-01

    When the Lagrangian relaxation technique is used to solve hydrothermal scheduling problems, many subproblems have linear stage-wise cost functions. A well recognized difficulty is that the solutions to these subproblems may oscillate between maximum and minimum generations with slight changes of the multipliers. Furthermore, the subproblem solutions may become singular, i.e., they are un-determined when the linear coefficients become zero. This may result in large differences between subproblem solutions and the optimal primal schedule. In this paper, a nonlinear approximation method is presented which utilizes nonlinear functions, quadratic in this case, to approximate relevant linear cost functions. The analysis shows that the difficulty associated with solution oscillation is reduced, and singularity is avoided. Extensive testing based on Northeast Utilities data indicates that the method consistently generates better schedules than the standard Lagrangian relaxation method.

  8. Short Time and Low Temperature Reaction between Metal Oxides through Microwave-Assisted Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    S. M. V. Novais

    2016-01-01

    Full Text Available This work demonstrates the possibility of synthesis of cadmium tungstate at low temperatures using oxide precursors. Cadmium tungstate (CdWO4 scintillator was produced via microwave-assisted hydrothermal reaction using the precursors CdO and WO3. The methodology was based on microwave radiation for heating, which is remarkably faster than the solid-state route or conventional hydrothermal procedure. CdWO4 monoclinic (wolframite structure was successfully obtained at 120°C for synthesis times as short as 20 min. This route does not require the use of templates or surfactants and yields self-assembled nanorods with size of around 24 ± 9 nm width and 260 ± 47 nm length. The growth mechanism for the formation of CdWO4 involves microwave-induced dissociation of the reagents and solvation of Cd2+ and WO42- ions, which are free to move and start the nucleation process. The luminescence properties of the produced nanoparticles were investigated, presenting a broad emission band at around 500 nm, which is comparable to that observed for samples produced using other chemical routes. This result highlights the great potential of the proposed method as a low-cost and time saving process to fabricate luminescent oxide nanoparticles.

  9. Preparation of hydroxyapatite whiskers by hydrothermal method; Suinetsuho ni yoru hidorokishi apataito hoisuka no gosei

    Energy Technology Data Exchange (ETDEWEB)

    Asaoka, N. [Mitsubishi Materials Corp., Tokyo (Japan). Electronics Technology Research Center; Suda, H. [National Inst. of Materials and Chemical Research, Tsukuba (Japan); Yoshimura, M. [Tokyo Inst. of Technology, Tokyo (Japan). Research Lab. of Engineering Materials

    1995-01-10

    In order to make good use of crystallographic anisotropy of hydroxyapatite (HAp : Ca10(PO4)6(OH)2) positively, synthesizing method for whiskery HAp crystals which are elongated along the C-axis has been investigated. Adding suitable amounts of citric acid (Cit.) on HAp slurries with two different concentrations of 1.7 and 4.4 wt%, these slurries became clear solutions. Each solution of 1.0L was hydrothermally treated respectively in an autoclave at a temperature 200{degree}C for 0,1,2,3,5 and 10h. As a result, no HAp whiskers could be obtained from the solutions containing 4.4 wt% of HAp. From the solutions containing 1.7% of HAp, whiskers could be obtained only when the Cit. /HAp ratio was more than 14.8 and the time of hydrothermal treatment was more than 3h. The whiskers were from 10 to 30{mu}m in length and about 0.5{mu}m in diameter. Excepting the above conditions, plate-like calcium hydrogenphosphate (monetite) was obtained in return. This writer took into consideration about the reason on the rise and fall of obtaining the whiskers. 17 refs., 8 figs.

  10. Preparation of ZnO nanosheets by a novel microemulsion-based hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Junying [College of Chemistry and Ecological Engineering, Guangxi University for Nationalities, Nanning 530006 (China); Wenshan Middle School, Weifang 261300 (China); Huang Zaiyin, E-mail: zaiyinhuang2010@163.com [College of Chemistry and Ecological Engineering, Guangxi University for Nationalities, Nanning 530006 (China); Tan Shengwei; Li Yanfen; Wang Guotao; Tan Xuecai [College of Chemistry and Ecological Engineering, Guangxi University for Nationalities, Nanning 530006 (China)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer We synthesized ZnO nanosheets via a novel hydrothermal method. Black-Right-Pointing-Pointer The ZnO nanosheets exhibited a clearly electrocatalytic response. Black-Right-Pointing-Pointer The ZnO nanosheets exhibited an intense green-yellow luminescence. Black-Right-Pointing-Pointer We discussed the formation mechanism of the prepared ZnO nanosheets. - Abstract: ZnO nanosheets have been successfully synthesized via a novel microemulsion-mediated hydrothermal route at 80 Degree-Sign C for 12 h. The compositions and morphologies of the as-prepared nanosheets were characterized by X-ray power diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and selected-area electron diffraction analysis (SAED). Electrochemical (EA) and photoluminescence analysis (PL) were employed to study their electrochemical behaviors and optical properties. It was found that these ZnO nanosheets had a single crystal hexagonal wurtzite structure with lattice constants of a = 0.3249 nm and c = 0.5205 nm. And they exhibited a clearly electrocatalytic response, indicating that the ZnO nanosheets could accelerate electron transfer of the electrochemical probe. The PL spectrum of ZnO nanosheets exhibited an intense green-yellow luminescence at the wavelength of 569 nm, which can be ascribed to the defects related to oxygen vacancies. The formation mechanism of the nanostructures was also proposed and discussed.

  11. Effects of La3+ doping on MnZn ferrite nanoscale particles synthesized by hydrothermal method

    Institute of Scientific and Technical Information of China (English)

    古映莹; 谭小平; 梁叔全; 桑商斌

    2004-01-01

    MnZn ferrite nanoscale particles were synthesized by hydrothermal method. The effects of amount of addition La3+ on the products were discussed. The product was characterized by X-ray diffraction (XRD) and transmission electron microscope (TEM). The results show that the sample with 0.2% La3+(mass fraction) or without La3+ has only spinel phase, but the sample with mass fraction of La3+ exceeding 0.4% posses second phase besides the spinel one; and the nano-MnZn ferrites change from cube to hexagon when the mass fractions of La3+ is up to 1.2%. TEM image of the sample with 1.2% La3+ indicates that the homogeneous hexagonal crystal is obtained and the particles are larger than those of undoped; the addition of La3+ has great influence on the crystallization of hydrothermal process and can change the shape of particles and improve their growth. The saturation magnetization of the sample with 1.2% La3+ (2.64 A·m2·kg-1) is lower than that of undoped (17.54 A·m2·kg-1) and it behaves superparamagnetically.

  12. Size effect of Raman scattering on CeO2 nanocrystal by hydrothermal method

    Science.gov (United States)

    Hattori, Takashi; Kobayashi, Katsutoshi; Ozawa, Masakuni

    2017-01-01

    In this study, we prepared surface-modified CeO2 nanocrystals (NCs) by a hydrothermal method, and calcined CeO2 NCs at various temperatures between 400 and 1000 °C for 3 h in air to obtain crystal-size-controlled CeO2 NCs. We investigated the correlation between the Raman spectra and the crystal sizes of the CeO2 powder. The peak position of the F2g mode of CeO2 was shifted to lower energies as the crystal size decreased and the peak broadened. The present hydrothermally driven CeO2 NCs showed no change in lattice constant depending on crystal size after heat treatment. The Raman peak position of the F2g mode as a function of inverse CeO2 crystal size corresponded to the models for phonon confinement without the combination of strain and defect effects. Moreover, it was also suggested that the Raman peak width of CeO2 NCs without strain also showed dependence on particle size.

  13. Ultrafast hydrothermal synthesis of high quality magnetic core phenol-formaldehyde shell composite microspheres using the microwave method.

    Science.gov (United States)

    You, Li-Jun; Xu, Shuai; Ma, Wan-Fu; Li, Dian; Zhang, Yu-Ting; Guo, Jia; Hu, Jack J; Wang, Chang-Chun

    2012-07-17

    An ultrafast, facile, and efficient microwave hydrothermal approach was designed to fabricate magnetic Fe(3)O(4)/phenol-formaldehyde (PF) core-shell microspheres for the first time. The structure of the Fe(3)O(4)/PF core-shell microspheres could be well controlled by the in situ polycondensation of phenol and formaldehyde with magnetic Fe(3)O(4) clusters as the seeds in an aqueous solution without any surfactants. The effect of synthetic parameters, such as the feeding amounts of phenol, the dosages of formaldehyde, the reaction temperatures, and the microwave heating time, on the morphologies and sizes of the Fe(3)O(4)/PF microspheres were investigated in details. The phenol-formaldehyde shell is found to be evenly coated on Fe(3)O(4) clusters within 10 min of the irradiation. The as-prepared microspheres were highly uniform in morphology, and the method was found to allow the shell thickness to be finely controlled in the range of 10-200 nm. The properties of the composite microspheres were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetic analysis (TGA), Fourier transform infrared (FT-IR) spectra, X-ray diffraction (XRD), and vibrating sample magnetometer (VSM). The as-prepared Fe(3)O(4)/PF microspheres were monodisperse and highly dispersible in water, ethanol, N,N-dimethyformamide, and acetone, a beneficial quality for the further functionalization and applications of the Fe(3)O(4)/PF microspheres.

  14. Effect of lattice strain on structural and optical properties of ZnO nanorods grown by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Gautam, Khyati, E-mail: khyati34@gmail.com; Nirwal, Varun Singh; Singh, Joginder; Peta, Koteswara Rao; Bhatnagar, P. K. [Department of Electronic Science, University of Delhi South Campus, Benito Juarez Road, New Delhi-110021 (India); Singh, Inderpreet [Department of Electronics, SGTB KhalsaCollege, University of Delhi, Delhi-110007 (India)

    2016-05-06

    In this work, we have synthesized ZnO nanorods over ZnO seeds/ITO/glass substrate by the facile hydrothermal method. ZnO seeds are grown at different temperatures ranging from 150°C to 550°C in steps of 100°C. We have studied the effect of strain on the structural and optical properties of ZnO nanorods. It was observed that the growth temperature of seed layer has an influence over the lattice strain present in the nanorods. The as synthesized nanorods were characterized by scanning electron microscope (SEM), x-ray diffraction (XRD) and photoluminescence (PL). SEM images confirm the formation of dense arrays of vertically aligned nanorods on seeds which are grown at 350°C. In addition to this, XRD patterns reveal that these ZnO nanorods are preferentially oriented along (002) direction. The strain analysis based on the XRD results reveals that the minimum value of strain is obtained at 350°C which is attributed to the improved crystalline quality of the interface of seed layer and nanorods leading to their c-axis alignment and enhancement of ultraviolet emission as observed in the PL spectra.

  15. Ion beam analysis of zeolites type Li-ABW synthesized by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, E.; De Lucio, O. G.; Solis, C.; Zavala, E. P.; Cruz, J. [UNAM, Instituto de Fisica, Circuito Exterior, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Alfaro, S.; Rodriguez, C.; Valenzuela, M. A. [IPN, Escuela Superior de Ingenieria Quimica e Industrias Extractivas, Laboratorio de Catalisis y Materiales, Zacantenco, 07738 Mexico D. F. (Mexico); Rocha, M. F. [IPN, Escuela Superior de Ingenieria Mecanica y Electrica, Av. Instituto Politecnico Nacional s/n, Col. Lindavista, 07738 Mexico D. F. (Mexico); Murillo, G.; Policroniades, R. [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico)

    2010-02-15

    This work reports a method to synthesize and characterize Li-ABW zeolites by a hydrothermal method. These materials are good candidates for CO{sub 2} capture because of the high reactivity between the Li{sup +} with CO{sub 2} to form Li{sub 2}CO{sub 3}. We performed and elemental profile concentration using ion beam analysis. The elastic backscattered proton energy spectra from the Al, Si, O and Li nuclei, in combination with the {alpha} particles from the {sup 7}Li ({rho}, {alpha}){sup 4}He nuclear reaction energy spectra, were employed for this task. X-ray diffraction was also applied to determine the crystalline structure. (Author)

  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. Controllable preparation of flower-like brookite TiO{sub 2} nanostructures via one-step hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Yunling [School of Chemical Engineering, Tianjin University, Tianjin 300072 (China); College of Science, Civil Aviation University of China, Tianjin 300300 (China); Tan, Xin [School of Science, Tibet University, Lhasa 850000 (China); Yu, Tao, E-mail: yutao@tju.edu.cn [School of Chemical Engineering, Tianjin University, Tianjin 300072 (China); Li, Yan; Li, Yimei; Wang, Ru; Xue, Lingqian [College of Science, Civil Aviation University of China, Tianjin 300300 (China)

    2016-08-15

    Highlights: • Flower-like brookite TiO{sub 2} structures were prepared by hydrothermal method. • PVP not only acted as a dispersant but also stabilized the layered structure. • The resulted brookite TiO{sub 2} showed high photocatalytic activity under UV irradiation. - Abstract: Flower-like brookite TiO{sub 2} nanostructures were controllable prepared by a one-step hydrothermal method by changing experimental conditions, such as hydrothermal temperature, reaction time and the amount of polyvinylpyrrolidone. The photocatalytic activities of the samples were investigated by degradation of methylene blue (MB) in aqueous solution under UV light irradiation. It was found that the formation of brookite TiO{sub 2} nanostructures with various morphologies could be well controlled by the adjustment of hydrothermal temperature, reaction time and the amount of surfactant, and the morphology of the products changed from spindle-like structures to flower-like structures with the increase of hydrothermal temperature, reaction time and the amount of surfactant. The photocatalytic tests indicate that the flower-like brookite TiO{sub 2} nanostructures shows high photocatalytic activity in degradation of methylene blue (MB) under UV light irradiation. The formation mechanism of flower-like brookite TiO{sub 2} nanostructures was also discussed in detail based on the above investigations.

  18. 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.

  19. Temperature dependent morphology variation of red emitting microcrystalline YPO4:Eu3+ fabricated by hydrothermal method

    Science.gov (United States)

    Cybińska, Joanna

    2017-03-01

    Phosphor materials based on the orthophosphates have been widely investigated in the past as crystals, bulk, or nanomaterials. These non-hydroscopic matrices are able to accommodate high concentrations of lanthanide ions without suffering of concentration quenching of the luminescence. One of the most important issue, which is necessary to overcome to use these materials as a phosphors it is to find a synthesis route giving a control over the products morphology, what allows to manage their spectroscopic properties. The investigated YPO4:Eu3+ samples doped with 5 mol % of optically active ions were prepared by the classic hydrothermal method. By changing the temperature of the synthesis it is possible to control the shape and the size of the particles. Based on the results obtained from the electron microscopy studies (TEM and SEM) the morphology of the obtained materials has been correlated with their optical properties such as decay times or emission quantum yields.

  20. 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.

  1. Flower-like CuO synthesized by CTAB-assisted hydrothermal method

    Indian Academy of Sciences (India)

    Yunling Zou; Yan Li; Nan Zhang; Xiulin Liu

    2011-07-01

    Flower-like CuO nanostructures have been synthesized by cetyltrimethylammonium bromide (CTAB)-assisted hydrothermal method. Here, CuCl2.2H2O was used as copper raw material, and sodium hydroxide was used as precipitate. The resulting CuO powders were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). X-ray diffraction (XRD) pattern exhibited the nanocrystalline nature with monoclinic structure for the as-synthesized nanostructures. FESEM images indicated that the flower-like CuO nanostructures are composed of many interconnected nanosheets in size of several micrometres in length and width and 60–80 nm in thickness. The possible formation mechanism of flower-like CuO nanostructures was discussed.

  2. 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.

  3. Influence of Heat Treatment on Photocatalytic Performance of BiVO4 Synthesized by Hydrothermal Method

    Science.gov (United States)

    Shen, Yi; Wang, Xiaomin; Zuo, Guifu; Li, Fengfeng; Meng, Yanzhi

    2016-10-01

    Monoclinic BiVO4 photocatalyst was successfully synthesized by hydrothermal method under appropriate temperature. The photocatalytic performance of BiVO4 was improved by calcining at appropriate temperature. The structural and morphological properties of the synthesized BiVO4 photocatalysts were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. It is confirmed that the photocatalytic activity of the prepared catalysts was evaluated by the photodegradation of RhB under visible-light irradiation. BiVO4 calcined under appropriate temperature exhibited higher photocatalytic activity than uncalcined BiVO4 under visible light irradiation because calcination might effectively increases the purity of monoclinic bismuth vanadate.

  4. Stable Electron Field Emission from CeO2 Nanowires by Hydrothermal Method

    Institute of Scientific and Technical Information of China (English)

    FU Xing-Qiu; FENG Ping; WANG Chong; WANG Tai-Hong

    2007-01-01

    @@ CeO2 nanowires are successful synthesized by hydrothermal method and their field emission (FE) properties are investigated. The turn-on electric field is 5.8 V/μm at an emitter-anode spacing of 700μm. The FE current is stable and the current fluctuations are less than 3% over 5 h. All the plotted Fowler-Nordheim curves yield straight lines, which are in agreement with the Fowler-Nordheim theory. The relationship between the field enhancement factorβ and the emitter-anode spacing d follows a universal equation. Our results imply that the CeO2 nanowires are promising materials for fabricating FE cathodes.

  5. A controllable hydrothermal method to prepare La(OH)3 nanorods using new precursors

    Institute of Scientific and Technical Information of China (English)

    Mehdi Mousavi-Kamazani; Sakineh Alizadeh; Fateme Ansari; Masoud Salavati-Niasari

    2015-01-01

    Using the hydrothermal method, lanthanum hydroxide nanorods were synthesized by the reaction of LaCl3·7H2O, ethyl-enediamine, and hydrazine. According to SEM results, ethylenediamine and hydrazine with pH management could control the parti-cle growth and played an important role in formation of lanthanum hydroxide nanorods. The morphology and microstructure of the obtained products were characterized by X-ray diffraction (XRD) spectra, energy-dispersive X-ray spectroscopy (EDX), Fourier transformed infrared (FTIR) spectrum, transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Further-more, the effects of the molar ratio of the precursors as well as the reaction temperature and time on the morphology and particle size of the products were investigated.

  6. The gas sensing properties of TiO2 nanotubes synthesized by hydrothermal method

    Institute of Scientific and Technical Information of China (English)

    Yan Li Wang; Shun Tan; Jia Wang; Zhi Jin Tan; Qiu Xia Wu; Zheng Jiao; Ming Hong Wu

    2011-01-01

    In this paper, the TiO2 nanotubes were synthesized by hydrothermal method usinga 10 mol/LNaOH aqueous solution at 150 ℃. The structure of prepared materials was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscope (SEM) and Brunauer-Emmett-Teller (BET). The prepared TiO2 nanotubes were used to prepare thick film gas sensors and the gas sensing properties to various gases were tested. Results show the prepared TiO2 nanotube gas sensors responses to ethanol under dry condition at 450 ℃. This could be attributed to the fact that it had high porous morphology and a higher pore volume, which can promote the diffusion of ethanol deep inside the films and improve the sensor response. Moreover, the gas sensor made with nanotubes exhibit high selective response towards ethanol gas compared with H2, CO, acetone.

  7. 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.

  8. Novel bismuth tri-iodide nanostructures obtained by the hydrothermal method and electron beam irradiation

    Science.gov (United States)

    Aguiar, Ivana; Olivera, Alvaro; Mombrú, Maia; Bentos Pereira, Heinkel; Fornaro, Laura

    2017-01-01

    Bismuth tri-iodide is a layered compound semiconductor which has suitable properties as material for ionizing radiation detection devices. Monocrystals and polycrystalline thin films have been studied for this application, but only recently, the development of nanostructures of this compound has emerged as an interesting alternative for using such nanostructures in new types of radiation detectors or for including them in other applications. Considering this, we present in this work BiI3 nanoparticles successfully synthesized by the hydrothermal method, using a Teflon-lined stainless steel autoclave, at a temperature of 180 °C during 8-20 h, with BiCl3 and NaI as source materials. We characterized the nanoparticles by X-ray diffraction (XRD), transmission electron microscopy (TEM) and electron dispersive spectroscopy (EDS). We obtained small rounded or hexagonal particles (10-20 nm in size) and larger structures. The maximum orientation of the nanostructures is along the (0 0 l) family planes and occurs after 16 h of synthesis, which arises as the best condition for obtaining BiI3 oriented nanostructures. When a 100 kV TEM electron beam was converged on the larger structures, we obtained highly oriented BiI3 hexagonal and rod shaped nanostructures. We found that particles' shape does not depend on the synthesis time. In addition, results were compared with the ones obtained for nanoparticles synthesized from solution. The present work is an advance in the synthesis of BiI3 nanostructures by the hydrothermal method, and is also the first step on seeking the amenable control of morphology and size of such structures using electron beam irradiation. This last process may be particularly appropriate for producing nanostructures for future applications in new devices.

  9. 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.

  10. Photocatalytic Degradation of Rhodamine B Dye with High Purity Anatase Nano-TiO2 Synthesized by a Hydrothermal Method

    Institute of Scientific and Technical Information of China (English)

    SHI Xiaoliang; YANG Xingyong; WANG Shuwei; WANG Sheng; ZHANG Qiaoxin; WANG Yufu

    2011-01-01

    High purity anatase nano-TiO2 powders with high photocatalytic activity were prepared by a hydrothermal synthesis method.X-ray diffraction(XRD),field emission transmission electron microscopy (FETEM),ultraviolet-visible(UV-Vis)light absorption spectrum and photoluminescence(PL)spectrum were adopted to characterize the catalyst.Effects of temperature,time and sol concentration of hydrothermal synthesis on particle size and phases were investigated.Photocatalytic activities in the degradation of Rhodamine B Dye were studied.The experimental results indicated that photocatalytic activity of the nano-TiO2 powers was much higher than that of P25(Degussa).

  11. 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.

  12. The Growth of TiO2 Nanostructures Prepared by Anodization in Combination with Hydrothermal Method on the Ti Foil

    OpenAIRE

    Mekla Vatcharinkorn; Juisuwannathat Charuwan; Tipparach Udom

    2015-01-01

    We have investigated TiO2 nanostructures prepared by anodization in conjunction with hydrothermal method using Ti metal plates. The TiO2 nanoporus were fabricated by electrochemical anodization in a NH4F/EG4/H2O electrolyte system. Ultrasonic wave was used to clean the surface of TiO2 nanoporus in the medium of water after completing the anodization. After drying in air, the nanoporusarrays were calcined at 450 °C for 2 h in air. The TiO2 nanostructures were converted by hydrothermal in air.T...

  13. Photocatalysis of WO3 Nanoplates Synthesized by Conventional-Hydrothermal and Microwave-Hydrothermal Methods and of Commercial WO3 Nanorods

    Directory of Open Access Journals (Sweden)

    Jarupat Sungpanich

    2014-01-01

    Full Text Available The degradation of methylene blue (MB dye by tungsten oxide (WO3 photocatalyst synthesized by the 200°C conventional-hydrothermal (C-H and 270 W microwave-hydrothermal (M-H methods and commercial WO3 was studied under UV light irradiation for 360 min. The photocatalysts were characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM, transmission electron microscopy (TEM, Fourier transform infrared (FTIR spectroscopy, Raman spectrophotometry, and UV visible spectroscopy to determine phase, morphology, vibration mode, and optical property. The BET analysis revealed the specific surface area of 29.74, 37.25, and 33.56 m2/g for the C-H WO3 nanoplates, M-H WO3 nanoplates, and commercial WO3 nanorods, respectively. In this research, the M-H WO3 nanoplates have the highest photocatalytic efficiency of 90.07% within 360 min, comparing to the C-H WO3 nanoplates and even commercial WO3 nanorods.

  14. An iron molybdate catalyst for methanol to formaldehyde conversion prepared by a hydrothermal method and its characterization

    NARCIS (Netherlands)

    Beale, A.M.; Jacques, S.D.M.; Sacaliuc-Parvulescu, E.; O'Brien, M.G.; Barnes, P.; Weckhuysen, B.M.

    2009-01-01

    A one-step, low-temperature hydrothermal method has been successfully employed to prepare iron molybdate catalysts with Mo:Fe ratios ranging from 1.5:1 to 3.0:1. The resulting materials were characterized using a number of techniques including: XRD, Raman, N2 adsorption, SEM/EDX, DTA, EDXRD and comb

  15. An integrated lean-methods approach to hospital facilities redesign.

    Science.gov (United States)

    Nicholas, John

    2012-01-01

    Lean production methods for eliminating waste and improving processes in manufacturing are now being applied in healthcare. As the author shows, the methods are appropriate for redesigning hospital facilities. When used in an integrated manner and employing teams of mostly clinicians, the methods produce facility designs that are custom-fit to patient needs and caregiver work processes, and reduce operational costs. The author reviews lean methods and an approach for integrating them in the redesign of hospital facilities. A case example of the redesign of an emergency department shows the feasibility and benefits of the approach.

  16. Research progress in preparation of nano - oxides by hydrothermal method%水热法制备纳米氧化物的研究进展

    Institute of Scientific and Technical Information of China (English)

    郑兴芳

    2009-01-01

    简述了水热法的原理和特点.介绍了水热晶化法、水热氧化法、水热还原法、水热沉淀法、水热分解法、水热合成法制备纳米氧化物的特点和现状,并介绍了水热法与其他方法的联合应用,如:微波-水热法、微乳液-水热法、溶胶(凝胶)-水热法等制备纳米氧化物的研究进展.最后对水热法制备纳米氧化物进行了展望.%Principle and characteristics of hydrothermal method were briefly introduced.Characteristics and present situ - ation of hydrothermal methods,including hydrothermal - crystallization,oxidation,reduction,precipitation,decomposition,and synthesis - methods,of nano - oxides were reviewed.Research progress in combination of hydrothermal method with other synthetic methods,such as microwave-hydrothermal,microemulsion-hydrothermal,and sol(gel)-hydrothermal,which were applied in preparation of nano - oxides were also discussed.At last,preparation of nano - oxides by hydrothermal method was also prospected.

  17. Controlled growth of well-aligned ZnO nanorod arrays by hydrothermal method

    Science.gov (United States)

    Mihailova, I.; Gerbreders, V.; Bulanovs, A.; Tamanis, E.; Sledevskis, E.; Ogurcovs, A.; Sarajevs, P.

    2014-10-01

    The application prospect of zinc oxide (ZnO) nanostructures largely relies on the ability to grow nanoobjects with necessary geometry. In this study well-aligned ZnO nanorod arrays with a high density and uniformity were successfully synthesized on the glass substrates by a hydrothermal method at low-temperature. The aqueous solutions of zinc nitrate hexahydrate and hexamethylenetetramine was used. The effect of seed layer (obtained by electrochemical method and by vacuum deposition method) on the alignment of ZnO nanorods has been investigated. The morphological properties of the ZnO nanorods were also examined in accordance with varying the magnetron sputtering angle for ZnO seeds deposition. It is also shown that the electric field can control the direction of the growth of ZnO nanorods. Morphological, structural and compositional characterizations of obtained films were carried out by scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction analysis methods.

  18. Facilities and methods for radioactive ion beam production

    CERN Document Server

    Blumenfeld, Y; Van Duppen, P

    2013-01-01

    Radioactive ion beam facilities are transforming nuclear science by making beams of exotic nuclei with various properties available for experiments. New infrastructures and development of existing installations enlarges the scientific scope continuously. An overview of the main production, separation and beam handling methods with focus on recent developments is done, as well as a survey of existing and forthcoming facilities world-wide.

  19. Vertically aligned ZnO nanorod grown by hydrothermal based chemical method on glass substrate

    Science.gov (United States)

    Srivastava, R.; Majumdar, S.; Bhunia, S.

    2012-06-01

    A low-temperature and effective precursor-based method has been demonstrated to synthesize nanostructured ZnO. It is found that the morphology of ZnO precursors has a strong dependence on the reaction conditions that include the molar ratio of reagents, solvent, and reaction temperature. In this work, ZnO nanostructures were synthesized via hydrothermal based chemical method. Zinc acetate dehydrate [Zn(Ac)2 2H2O] and 1-propanol(C3H8O) were adopted for a seed layer growth on glass substrate via spin coating technique. Zinc nitrate hexahydrate [Zn(NO3)2 6H2O], hexamethylenetetramine(C6H12N4) and diethylamine(C4H11N) were adopted as synthesis precursors. The ZnO nanostructures obtained were characterized by scanning electronic microscopy (SEM) and the PL method. The SEM image of the sample showed that the thin film of ZnO on glass substrate has, predominantly, a nanometric rod-like morphology with hexagonal wurtzite structure.

  20. Preparation and magnetic properties of nano size nickel ferrite particles using hydrothermal method

    Directory of Open Access Journals (Sweden)

    Nejati Kamellia

    2012-03-01

    Full Text Available Abstract Background Nickel ferrite, a kind of soft magnetic materials is one of the most attracting class of materials due to its interesting and important properties and has many technical applications, such as in catalysis, sensors and so on. In this paper the synthesis of NiFe2O4 nanoparticles by the hydrothermal method is reported and the inhibition of surfactant (Glycerol or Sodium dodecyl sulfate on the particles growth is investigated. Methods For investigation of the inhibition effect of surfactant on NiFe2O4 particles growth, the samples were prepared in presence of Glycerol and Sodium dodecyl sulfate. The X-ray powder diffraction (XRD, transmission electron microscopy (TEM, Fourier transform infrared spectroscopy (FT-IR, vibrating sample magnetometer (VSM and inductively coupled plasma atomic emission spectrometer (ICP-AES techniques were used to characterize the samples. Results The results of XRD and ICP-AES show that the products were pure NiFe2O4 and also nanoparticles grow with increasing the temperature, while surfactant prevents the particle growth under the same condition. The average particle size was determined from the Scherrer's equation and TEM micrographs and found to be in the range of 50-60 nm that decreased up to 10-15 nm in presence of surfactant. The FT-IR results show two absorption bands near to 603 and 490 cm-1 for the tetrahedral and octahedral sites respectively. Furthermore, the saturated magnetization and coercivity of NiFe2O4 nanoparticles were in the range of 39.60 emu/g and 15.67 Qe that decreased for samples prepared in presence of surfactant. As well as, the nanoparticles exhibited a superparamagnetic behavior at room temperature. Conclusions Nanosized nickel ferrite particles were synthesized with and without surfactant assisted hydrothermal methods. The results show that with increasing of temperature, the crystallinity of nanoparticles is increased. In the presence of surfactants, the crystallinity of

  1. Facile one-step hydrothermal synthesis toward strongly coupled TiO2/graphene quantum dots photocatalysts for efficient hydrogen evolution

    Science.gov (United States)

    Min, Shixiong; Hou, Jianhua; Lei, Yonggang; Ma, Xiaohua; Lu, Gongxuan

    2017-02-01

    The coupling of semiconductor photocatalysts with graphene quantum dots (GQDs) has been proven to be an effective strategy to enhance the photocatalytic and photoelectrical conversion performances of the resulted composites; however, the preparation of semiconductor/GQDs composites usually involves several time-inefficient and tedious post-treatment steps. Herein, we present a facile one-step hydrothermal route for the preparation of GQDs coupled TiO2 (TiO2/GQDs) photocatalysts using 1,3,6-trinitropyrene (TNP) as the sole precursor of GQDs. During the hydrothermal process, TNP molecules undergo an intramolecular fusion to form GQDs, which simultaneously decorate on the surface of TiO2 nanoparticles, leading to a strong surface interaction between the two components. The effective coupling of GQDs on TiO2 can effectively extend the light absorption of the TiO2 to visible region and enhance the charge separation efficiency of TiO2/GQDs composites as a result of GQDs acting as a photosensitizer and an excellent electron acceptor. These key advances make the TiO2/GQDs photocatalyst highly active towards the H2 evolution reaction, resulting in 7 and 3 times higher H2 evolution rate and photocurrent response at optimal GQDs content than TiO2 alone, respectively. This study provides a new methodology for the development of high-performance GQDs modified semiconductor photocatalysts for energy conversion applications.

  2. Synthesis of High-Density Poinsettia-Like Microstructure of CuO by the Hydrothermal Method and Its Ethanol Sensing Properties

    Science.gov (United States)

    Hien, Vu Xuan; Minh, Vu Duy; Phuoc, Luong Huu; Vuong, Dang Duc; Heo, Young-Woo; Chien, Nguyen Duc

    2017-06-01

    Highly uniform and dense poinsettia-like microstructures of CuO were synthesized by a facile hydrothermal method. The effect of the treatment time on the growth of the CuO microstructures was investigated. The CuO microflowers with diameters in the range 3-5 μm were composed of many interconnected nanoleaves (1-2 μm in diameter and 20-30 nm in thickness). A plausible growth mechanism for the formation of the CuO microstructures has been proposed and discussed. In addition, the ethanol sensing properties of the CuO microflowers were characterized at 150-350°C. The poinsettia-like microstructures of CuO exhibited better response to ethanol when compared to the sensing properties of the CuO nanoleaves. The sensing mechanism based on the models of carrier transport and leaf-to-leaf contact has been proposed and discussed.

  3. A facile approach to the elucidation of magnetic parameters of CuFe2O4 nanoparticles synthesized by hydrothermal route

    Science.gov (United States)

    Kurian, Jessyamma; Jacob Mathew, M.

    2017-04-01

    Pure pseudo cubic shaped copper ferrite nanoparticles with narrow size distribution in the range 6-17 nanometer are prepared by hydrothermal method under various synthesis conditions namely, hydrothermal temperature, heating time, and pH. The structural and morphological studies are carried out in detail using XRD and TEM analysis. The crystallite size and particle size are calculated from different characterization techniques. The distribution of cations among the tetrahedral and octahedral sites is determined from the XRD intensity calculation. Compositional features are determined from EDS analysis. Magnetic studies are carried out using VSM at room temperature and the important magnetic parameters are extracted from it. Contributions due to various types of magnetization to the total magnetization are determined from the theoretical fitting of the magnetization curve. Excellent fits are obtained for all samples prepared under various conditions. The ferromagnetic, superparamagnetic and paramagnetic contributions to the magnetization are determined from the analysis of fitted M-H curve. It is observed that the hydrothermal reaction time and temperature has little effect on the structural and magnetic parameters of the material. However, pH plays a crucial role in the physical properties of nanoparticles. Optimized synthesis conditions are identified for changing the soft ferrimagnetic nature of copper ferrite nanoparticles to superparamagnetic nature.

  4. Systematic study on surface and magnetostructural changes in Mn-substituted dysprosium ferrite by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Rekha, G. [Department of Physics, College of Engineering Guindy, Anna University, Sardar Patel Road, Chennai 600025 (India); Tholkappiyan, R. [Department of Physics, College of Engineering Guindy, Anna University, Sardar Patel Road, Chennai 600025 (India); Department of Physics, College of Science, UAE University, Al-Ain 15551 (United Arab Emirates); Vishista, K., E-mail: raovishista@gmail.com [Department of Physics, College of Engineering Guindy, Anna University, Sardar Patel Road, Chennai 600025 (India); Hamed, Fathalla [Department of Physics, College of Science, UAE University, Al-Ain 15551 (United Arab Emirates)

    2016-11-01

    Highlights: • Garnet type Dy{sub 3}Fe{sub 5-x}Mn{sub x}O{sub 12} (x = 0–0.06) nanoparticles of 88.4–86.8 nm were synthesized by hydrothermal method. • The Dy, Mn, Fe and O elements in the ferrites were confirmed from XPS. • The multiple oxidation states of Fe and Mn ions, bonding energy and cationic distributions of the samples were examined by XPS. • The magnetic property shows ferromagnetic behavior from VSM technique. • The results from these studies are correlated with respect to Mn dopant. - Abstract: Dysprosium iron garnets are of scientific importance because of the wide range of magnetic properties that can be obtained in substituting dysprosium by a rare earth metal. In the present work, the effect of Mn substitution on magnetostructural changes in dysprosium ferrite nanoparticles is studied. Highly crystalline pure and Mn doped dysprosium ferrite nanoparticles were synthesized by hydrothermal method. The samples were calcined at 1100 °C for 2 h in air atmosphere which is followed by characterization using XRD, FT-IR analysis, SEM, XPS and VSM. The average crystallite size of synthesized samples were calculated by X-ray diffraction falls in the range of 88.4–86.8 nm and was found to be in cubic garnet structure. For further investigation of the structure and corresponding changes in the tetrahedral and octahedral stretching vibrational bonds, FT-IR was used. The synthesized samples consist of multiple oxidation (Fe{sup 3+} and Fe{sup 2+}) states for Fe ions and (Mn{sup 3+} and Mn{sup 2+}) Mn ions analyzed in three ways of Fe 2p and Mn 2p spectra from the XPS analysis. With respect to Mn dopant in Dy{sub 3}Fe{sub 5}O{sub 12}, the cationic distributions of elements were discussed from high resolution XPS spectra by peak position and shift, area, width. To find out the porous/void surface morphology of the sample, scanning electron microscopy was used. From XPS analysis, the presence of elements (Dy, Mn, Fe and O) and their composition in the

  5. Morphology and wettability of ZnO nanostructures prepared by hydrothermal method on various buffer layers

    Science.gov (United States)

    Li, Bao-jia; Huang, Li-jing; Zhou, Ming; Ren, Nai-fei

    2013-12-01

    Zinc oxide (ZnO) nanostructures were prepared by hydrothermal method on glass substrates with various buffer layers: Ag, Al, aluminum-doped zinc oxide (AZO) and tin-doped indium oxide (ITO). The structure, morphology and wettability of the ZnO nanostructured surfaces were investigated by using X-ray diffraction, scanning electron microscopy and water contact angle (WCA) analysis methods, respectively. All the nanostructures grown on glass with various buffer layers exhibited strong growth orientation along the (1 0 1) plane. The nature of the buffer layer was found to have remarkable effect on the morphology and wettability of the ZnO nanostructures. Whether the buffer layers were hydrophilic or low hydrophobic, all the ZnO nanostructures grown on the various buffer layers showed high hydrophobic property, and that grown on the AZO buffer layer even exhibited superhydrophobicity with a WCA of 151.1°. This work may provide a scientific basis for self-cleaning ZnO-based optoelectronic device applications.

  6. Immobilization of nanoparticle titanium dioxide membrane on polyamide fabric by low temperature hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Hui, E-mail: hzhangw532@xpu.edu.cn; Yang Lu

    2012-07-01

    A thin layer of nanoparticle titanium dioxide was immobilized on polyamide 6 (PA6) fiber using titanium sulfate and urea at low temperature hydrothermal condition. The titanium dioxide loaded fabric was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry and thermal gravimetry techniques. The optical and mechanical properties, water absorption and degradation of methylene blue dye under ultraviolet (UV) irradiation of the PA6 fabric before and after treatments were also examined. It was found that when PA6 fabric was treated in titanium sulfate and urea aqueous solution, anatase nanocrystalline titanium dioxide was synthesized and simultaneously adhered onto the fiber surface. The average crystal size of titanium dioxide nanoparticles was about 13.2 nm. The thermal behavior of PA6 fiber distinctly changed and the onset decomposition temperature decreased. As compared with the untreated fabric, the protection against UV radiation was improved. The water absorbency increased slightly. As the fabric dimensions were reduced in warp and weft directions, the breaking load and tensile strain increased to some extent. The titanium dioxide coated fabric could degradate methylene blue dye under UV irradiation. - Highlights: Black-Right-Pointing-Pointer We employed a method to immobilize TiO{sub 2} nanoparticle on polyamide fiber. Black-Right-Pointing-Pointer We fabricated the TiO{sub 2}-coated polyamide fabric with the photocatalytic activity. Black-Right-Pointing-Pointer The modification method may be suitable for the potential applications.

  7. Magnetic properties of cobalt oxide nanoparticles synthesised by a continuous hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Moro, Fabrizio, E-mail: fabrizio.moro@manchester.ac.uk [School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Yu Tang, Selina Vi [Department of Chemical and Environmental Engineering, Faculty of Engineering, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Promethean Particles Ltd, 6 Faraday Building, Nottingham Science Park, University Boulevard, Nottingham NG7 2QP (United Kingdom); Tuna, Floriana [EPSRC National UK EPR Facility, Photon Science Institute, University of, Manchester, Manchester M13 9PL (United Kingdom); School of Chemistry, University of Manchester, Manchester M13 9PL (United Kingdom); Lester, Edward, E-mail: Edward.Lester@nottingham.ac.uk [Department of Chemical and Environmental Engineering, Faculty of Engineering, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Promethean Particles Ltd, 6 Faraday Building, Nottingham Science Park, University Boulevard, Nottingham NG7 2QP (United Kingdom)

    2013-12-15

    We use a Nozzle reactor, for the rapid and simple synthesis of antiferromagnetic Co{sub 3}O{sub 4} nanoparticles with tailored structural and magnetic properties based on continuous-flow hydrothermal method. XRD and TEM studies show that the as-synthesised nanoparticles possess cubic morphology, high degree of crystallinity and an average size of 7 nm. Furthermore, SQUID and electron spin resonance (ESR) studies reveal interesting magnetic properties for practical applications such as weak ferromagnetism, spin canting, exchange bias effect at low temperatures and superparamagnetic behaviour at room temperature. The Nozzle reactor has also been successfully increased from bench-scale (grams/hour) to commercial scale (tonnes/annum) production of nanomaterials with good reproducibility, demonstrating the feasibility of developing Co{sub 3}O{sub 4} nanoparticles for commercial applications. - Highlights: • We apply a novel continuous method for the synthesis of magnetic nanoparticles with tailored structural and magnetic properties. • Cubic Co{sub 3}O{sub 4} nanoparticles were synthesised with an average size of 7 nm. • Superparamagnetic behaviour was found at room temperature. • Weak ferromagnetism appears at low temperatures. • Observed exchange bias effect.

  8. Degradation of Tetracycline with BiFeO3 Prepared by a Simple Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Zhehua Xue

    2015-09-01

    Full Text Available BiFeO3 particles (BFO were prepared by a simple hydrothermal method and characterized. BFO was pure, with a wide particle size distribution, and was visible light responsive. Tetracycline was chosen as the model pollutant in this study. The pH value was an important factor influencing the degradation efficiency. The total organic carbon (TOC measurement was emphasized as a potential standard to evaluate the visible light photocatalytic degradation efficiency. The photo-Fenton process showed much better degradation efficiency and a wider pH adaptive range than photocatalysis or the Fenton process solely. The optimal residual TOC concentrations of the photocatalysis, Fenton and photo-Fenton processes were 81%, 65% and 21%, while the rate constants of the three processes under the same condition where the best residual TOC was acquired were 9.7 × 10−3, 3.2 × 10−2 and 1.5 × 10−1 min−1, respectively. BFO was demonstrated to have excellent stability and reusability. A comparison among different reported advanced oxidation processes removing tetracycline (TC was also made. Our findings showed that the photo-Fenton process had good potential for antibiotic-containing waste water treatment. It provides a new method to deal with antibiotic pollution.

  9. Abnormal room temperature ferromagnetism in CuO/ZnO nanocomposites via hydrothermal method

    Science.gov (United States)

    Lu, Ping; Zhou, Wei; Li, Ying; Wang, Jianchun; Wu, Ping

    2017-03-01

    CuO/ZnO nanocomposites have been successfully synthesized by a one-step hydrothermal method with different phase ratios. Field emission scanning electron microscopy and transmission electron microscopy results show that the obtained products of nanosheets are composed of small primary particles with an average size of about 20 nm. With the increasing proportion of CuO phase, nanosheets have significant collapse and the amount of small sheets increases obviously. The abnormal room temperature ferromagnetism was discovered at the interface between diamagnetic ZnO and antiferromagnetic CuO, which can be tuned by changing the phase ratios. Optical spectra indicate that the interaction between ZnO and CuO modifies the electronic structure of nanocomposites. XPS results verify the valence change of Cu ions and the presence of oxygen vacancies, which are ultimately responsible for the observed ferromagnetism. The indirect double-exchange model was employed to explain the origin of magnetism. Our study suggests that magnetically functional interfaces exhibit very appealing properties for novel devices.

  10. 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.

  11. The Optical Properties of Crystalline Zn3Nb2O8 Nanomaterials Obtained by Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Mihaela Birdeanu

    2015-01-01

    Full Text Available The present study is focused on the obtaining of the Zn3Nb2O8 nanomaterial using the hydrothermal method and its characterization through different techniques. X-ray diffraction at room temperature revealed that a novel crystalline form of the nanomaterial forms at 1100°C belonging to monoclinic space group C2/c. Field-emission scanning electron microscopy evidenced the columnar morphology of the particle’s agglomeration and the high resolution electron transmission microscopy confirms the measured interplanar distances calculated from the X-ray diffraction experiments. Using the UV-VIS spectrum and Kubelka-Munk equations, the absorbance and the band gap for the Zn3Nb2O8 nanomaterial were calculated. PL spectrum reveals a single peak at 465 nm corresponding to the blue color fluorescence. The novel crystalline nanomaterial might find applications in fluorescence covering of technical devices, due to its capacity to preserve blue fluorescence both in acrylic based paint and after embedding in isopropyl alcohol.

  12. Void Structures in Regularly Patterned ZnO Nanorods Grown with the Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Yu-Feng Yao

    2014-01-01

    Full Text Available The void structures and related optical properties after thermal annealing with ambient oxygen in regularly patterned ZnO nanrorod (NR arrays grown with the hydrothermal method are studied. In increasing the thermal annealing temperature, void distribution starts from the bottom and extends to the top of an NR in the vertical (c-axis growth region. When the annealing temperature is higher than 400°C, void distribution spreads into the lateral (m-axis growth region. Photoluminescence measurement shows that the ZnO band-edge emission, in contrast to defect emission in the yellow-red range, is the strongest under the n-ZnO NR process conditions of 0.003 M in Ga-doping concentration and 300°C in thermal annealing temperature with ambient oxygen. Energy dispersive X-ray spectroscopy data indicate that the concentration of hydroxyl groups in the vertical growth region is significantly higher than that in the lateral growth region. During thermal annealing, hydroxyl groups are desorbed from the NR leaving anion vacancies for reacting with cation vacancies to form voids.

  13. Characterization and Photocatalytic Activity of Enhanced Copper-Silica-Loaded Titania Prepared via Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Ramarao Poliah

    2011-01-01

    Full Text Available TiO2 nanopowder, loaded with SiO2 and Cu-SiO2, was prepared under both acidic and basic environments via the hydrothermal method. The morphology and structure of TiO2 were studied by XRD, TEM, and FT-IR. The photocatalytic activity of samples was studied by monitoring the degradation of methyl orange, using a UV-visible spectrophotometer. The effect of Ti/Si ratio, pH, and Cu2+ addition on the formation of TiO2 and its photocatalytic activity was investigated in detail. The results show that a large surface area and a high surface acidity were important factors to achieve good TiO2 performance. The presence of Ti-O-Si bonding enhanced surface acidity, which improved its ability to adsorb more hydroxyl radicals and increased its surface area. The addition of 0.1 mol% concentration of Cu2+ and 25 mol% SiO2 in TiO2 induced the formation of new states close to the conduction band, which narrowed the band gap energy and enhanced the photodegradation efficiency.

  14. 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.

  15. 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.

  16. Biocompatibility and antimicrobial activity of zinc(II doped hydroxyapatite, synthesized by hydrothermal method

    Directory of Open Access Journals (Sweden)

    Kojić Vesna

    2012-01-01

    Full Text Available In order to obtain multifunctional materials with good biocompatibility and antimicrobial effect, hydroxyapatite (HAp doped with Zn2+ was synthesized by hydrothermal method. Powders with different content of zinc ions were synthesized and compared with undoped HAp to investigation of Zn2+ ion influence on the antimicrobial activity of HAp. Analyses of undoped and Zn2+-doped powders before and after thermal treatment at 1200ºC were performed by SEM and XRD. Antimicrobial effects of powders were examined in relation to Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans in liquid medium. The results showed that the obtained powders have good antimicrobial activity, but higher antimicrobial activities of powders doped with Zn2+ were observed after annealing at 1200°C. For powders annealed at 1200°C in vitro biocompatibility tests MTT and DET with MRC-5 fibroblast cells in liquid medium were carried out. Based on MTT and DET tests it was shown that powders do not have a significant cytotoxic effect, which was confirmed by SEM analysis of MRC-5 fibroblast cells after theirs in vitro contact with powders. [Projekat Ministarstva nauke Republike Srbije, br. III 45019 and FP7-REGPOT-2009-1 NANOTECH FTM

  17. Effect of Preparation Parameters on Photoactivity of BiVO4 by Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Qingyun Chen

    2012-01-01

    Full Text Available Bismuth vanadate (BiVO4 was synthesized from a mixture of aqueous Bi(NO33 and NH4VO3 solutions by using hydrothermal method. Via conducting the orthogonal experiments and single-factor experiments, the best synthetic parameters were determined. The physical and photophysical properties of the as-obtained samples were characterized by scanning electron microscopy (SEM, transmission electron microscopy (TEM, X-ray diffraction (XRD, and UV-Vis diffusion reflectance spectroscopy (UV-Vis. The result showed that the best experimental parameters of monoclinic BiVO4 were pH=7, T=195 °C, and    t=6 h. The catalytic performance of BiVO4 was evaluated by reducing carbon dioxide to methane under visible light irradiation. It was found that the methane production reached 145 μg/g-cat after 5 h irradiation with the catalyst dosage of 0.15 g in 200 mL mixed solution of 0.1 M NaOH and 0.1 M Na2SO3.

  18. Effects of precursor concentrations and thermal annealing on ZnO nanorods grown by hydrothermal method.

    Science.gov (United States)

    Cho, Min Young; Kim, Min Su; Yim, Kwang Gug; Lee, Dong-Yul; Kim, Jong Su; Kim, Jin Soo; Leem, Jae-Young

    2011-08-01

    ZnO nanorods were grown on spin-coated ZnO seed layers by hydrothermal method. The ZnO nanorods were grown with various precursor concentrations ranging from 0.01 to 0.3 M. Field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and photoluminescence (PL) were carried out to investigate the structural and optical properties of the ZnO nanorods. The average diameter and length of the ZnO nanorods is increased as the precursor concentration increased from 0.01 to 0.3 M. From XRD, the intensity of ZnO (002) peak is increased and full width at half maximum (FWHM) of ZnO (002) decreased as the precursor concentration increased. The FWHM of near-band-edge emission (NBE) decreased and intensity ratio of the NBE to the deep-level emission (DLE) increased as the precursor concentration increased which indicated the optical property is improved. The DLE is red-shifted from yellow- to red-emission and its intensity is increased as the annealing temperature increased due to thermal diffusion process.

  19. Gas sensing properties of graphene–WO{sub 3} composites prepared by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Chu, Xiangfeng, E-mail: xfchu99@ahut.edu.cn [School of Chemistry and Chemical Engineering, Anhui University of Technology, Maanshan 243002 (China); Hu, Tao [School of Chemistry and Chemical Engineering, Anhui University of Technology, Maanshan 243002 (China); Gao, Feng [Department of Materials Science and Engineering, Nanjing University, Nanjing 210093 (China); Dong, Yongping; Sun, Wenqi; Bai, Linshan [School of Chemistry and Chemical Engineering, Anhui University of Technology, Maanshan 243002 (China)

    2015-03-15

    Graphical abstract: - Highlights: • The amount of graphene had an effect on the morphology of graphene–WO{sub 3} composites. • The optimum temperature of 0.1 wt% graphene–WO{sub 3} sensor to acetaldehyde was 100 °C. • 0.1 wt% graphene–WO{sub 3} sensor exhibited good selectivity to acetaldehyde at 100 °C. - Abstract: Graphene–WO{sub 3} composites mixed with different amounts of graphene (0, 0.1, 0.5, 1 and 3 wt%) were prepared by hydrothermal method at 180 °C for 24 h. The as-prepared graphite oxide, graphene and graphene–WO{sub 3} composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectra (FT-IR) and Raman spectroscopy, respectively. The effect of the amount of graphene in the composites on the gas-sensing responses and the gas-sensing selectivity of the materials was investigated. The experimental results revealed that the sensor based on 0.1 wt% graphene–WO{sub 3} composite exhibited high response and good selectivity to acetaldehyde vapor at 100 °C, the optimum operating temperature of this sensor to 1000 ppm acetaldehyde vapor decreased from 180 °C to 100 °C comparing with that of pure WO{sub 3}. The response time and the recovery time for 100 ppm acetaldehyde vapor were 250 s and 225 s, respectively.

  20. Effect of anneal temperature on fluorine doped tin oxide (FTO) nanostructured fabricated using hydrothermal method

    Science.gov (United States)

    Ahmad, M. K.; Marzuki, N. A.; Soon, C. F.; Nafarizal, N.; Sanudin, R.; Suriani, A. B.; Mohamed, A.; Shimomura, M.; Murakami, K.; Mamat, M. H.; Malek, M. F.

    2017-01-01

    FTO thin films were prepared by the hydrothermal method at anneal temperature of 100°C-400°C using pentahydrate stannic chloride (SnCl4.5H2O) and ammonium fluoride (NH4F) as precursors, and a mixture of DI water, acetone and hydrochloride as a solvent. The X-ray diffraction studies confirmed the tetragonal structure with polycrystalline nature. The preferred directions of crystal growth appeared in the diffractogram of FTO thin films prepared with different anneal temperature were correspond to the reflection from the (101), (200) and (211) planes, respectively. The electrical study reveals that the films have degenerate and exhibit n-type electrical conductivity. For films prepared at 400°C, the relatively higher transmittance of about 85-90% at 800nm has been observed. The transmission attained in this study is greater than the values reported for tin oxide films prepared at anneal temperature 400°C, from an aqueous solution of SnCl4.5H2O precursor. Resistivity is smaller than the value reported. The obtained results revealed that the structures and properties of the films were greatly affected by anneal temperature

  1. P-doped TiO2 with superior visible-light activity prepared by rapid microwave hydrothermal method

    Science.gov (United States)

    Niu, Jinfen; Lu, Pan; Kang, Mei; Deng, Kunfa; Yao, Binghua; Yu, Xiaojiao; Zhang, Qian

    2014-11-01

    Phosphorous-doped anatase TiO2 powders (P-TiO2) were prepared by rapid microwave hydrothermal method. The resulting materials were characterized by XRD, SEM, XPS, DRS and N2 adsorption. P-doping decreased the band gap and enlarged the surface area of P-doped samples than that of undoped TiO2 samples. Therefore, the photocatalytic degradation of methyl blue (MB) and tetracycline hydrochloride (Tc) experiments showed that the P-TiO2 catalysts, especially the two-steps-controlling products P-TiO2-2, exhibited higher degradation efficiency than the undoped TiO2 and commercial P25 under visible-light irradiation. Hydroxyl radicals (rad OH) have been confirmed to be the active species during the photocatalytic oxidation reaction. The microwave hydrothermal method confirms to be very suitable for the synthesis of superior visible-light activity P-doped samples.

  2. Mid-long Term Optimal Dispatching Method of Hydro-thermal Power System Considering Scheduled Maintenance

    Institute of Scientific and Technical Information of China (English)

    GE Xiaolin; SHU Jun; ZHANG Lizi

    2012-01-01

    Mid-long term hydro-thermal optimal dispatching plays an important role in mid-long term electric power and energy balance, and it also can bring significant economic benefits. This topic has been discussed in many literatures and some progress has been achieved, but there are still two problems that need to be solved. First, the modeling approach needs to be improved. When a multi-scenario model is adopted in hydro-thermal optimal dispatching, the existing modeling approaches will probably suffer from the dimensionality problem. Second, the construction of the mathematical model is not comprehensive. Generally, the existing model only considers the power balance;

  3. Effects of hydrothermal annealing on characteristics of CuInS2 thin films by SILAR method

    Science.gov (United States)

    Shi, Yong; Xue, Fanghong; Li, Chunyan; Zhao, Qidong; Qu, Zhenping; Li, Xinyong

    2012-07-01

    CuInS2 thin films have been deposited by successive ionic layer absorption and reaction (SILAR) method, then annealed in a Na2S solution (denoted as hydrothermal annealing) at 200 °C for different time. The effect of hydrothermal annealing on the properties of the films was studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and optical absorption spectroscopy. The XRD, TEM and SEM results indicate that well-crystallized CuInS2 films could be obtained after annealing in 0.1 mol/L Na2S solution for 1.5 h. The annealed CuInS2 films were slightly S-rich and the direct band gap varied from 1.32 to 1.58 eV as the annealing time increased from 0.5 h to 2 h.

  4. Preparation of SiO2 nanowires from rice husks by hydrothermal method and the RNA purification performance

    Science.gov (United States)

    Huang, Meiyan; Cao, Jianping; Meng, Xing; Liu, Yangsi; Ke, Wei; Wang, Jialiang; Sun, Ling

    2016-10-01

    In this study, SiO2 nanowires were prepared by using rice husks as silicon source via a hydrothermal method. The microstructure, thermal stability and morphology of SiO2 nanowires were characterized by X-ray diffraction, infrared spectroscopy, thermal gravimetric analysis and scanning electron microscope. SiO2 nanowires with a diameter of 30-100 nm were obtained and the formation mechanism of SiO2 nanowires during the hydrothermal reaction was proposed. The SiO2 nanowires were introduced into membrane spin columns to isolate RNA and the values of A260/280 and A260/230 were 2.0-2.1 and 1.8-2.0, respectively, which shows the SiO2 nanowires were effective for RNA purification.

  5. Preparation of Co3O4 Nanostructures via a Hydrothermal- Assisted Thermal Treatment Method by Using of New Precursors

    Science.gov (United States)

    Gholamrezaei, Sousan; Salavati-Niasari, Masoud; Hadadzadeh, Hassan; Behnamfar, Mohammad Taghi

    2017-02-01

    Co3O4 nanostructures have been synthesized via a hydrothermal-assisted thermal treatment process. A new complex formulated as [Co(py)2(H2O)2(NO3)2] was synthesized, and then used to prepare Co3O4 nanostructures. Cubic phase of spinel Co3O4 nanostructures with particle size of about 39 nm could be produced after calcination of the Co(OH)2 materials prepared with hydrothermal method at 160 °C for 15 h. Using of inorganic precursors decreased the time and temperature of Co3O4 preparation. The effect of pH on the morphology of the product s synthesized by hydrothermal reactions was investigated. It was found that the best morphology was achieved on pH=8, where was not prepared any precipitation. In this method, we could decrease the reaction temperature in synthetic rout to fabricate Co3O4 nanostructures. Nanostructures were characterized by SEM, TEM, X-ray diffraction (XRD), UV-visible, Fourier transformed infrared (FT-IR) spectroscopy and Nuclear magnetic resonance (1H-NMR).

  6. Facile phase control for hydrothermal synthesis of anatase-rutile TiO{sub 2} with enhanced photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hong [Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China); Shen, Xiaojun [Faculty of Chemistry & Material Engineering, Wenzhou University, 276 Xueyuan Road, Zhejiang Province, Wenzhou 325027 (China); Liu, Yongdi [State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China); Wang, Lingzhi [Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China); Lei, Juying, E-mail: leijuying@ecust.edu.cn [State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China); Zhang, Jinlong, E-mail: jlzhang@ecust.edu.cn [Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China)

    2015-10-15

    Mixed-phase TiO{sub 2} photocatalysts with different proportions of anatase and rutile have been successfully synthesized in an acidic hydrothermal system, using tartaric acid (C{sub 4}H{sub 6}O{sub 6}) as a phase content regulator and titanium trichloride (TiCl{sub 3}) as the titanium source. The obtained samples were characterized by X-ray diffraction spectroscopy (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM) and so on. The phase contents of anatase and rutile in the TiO{sub 2} particles were successfully controlled by simply adjusting the molar ratio of C{sub 4}H{sub 6}O{sub 6} to TiCl{sub 3}. And the regulation degree could be further controlled by the concentration of sodium chloride (NaCl) in the reaction system. In addition, the effect of the reaction time, hydrothermal temperature and acidity on the phase structure of as-prepared products have also been investigated. A mechanism was proposed to interpret the evolution of the phases based on the experimental results. Finally, the photocatalytic activity of the prepared TiO{sub 2} were evaluated by the degradation of Rhodamine B (RhB) and methyl orange (MO) in aqueous solutions. The mixed-phase TiO{sub 2} exhibited higher activity than pure phase TiO{sub 2}, and the catalyst containing 77% anatase and 23% rutile had the highest photocatalytic activity. The enhanced photocatalytic activity could be explained by the mixed-phase effect between anatase and rutile. - Highlights: • Mixed-phase TiO{sub 2} with tunable proportions of anatase and rutile were obtained. • C{sub 4}H{sub 6}O{sub 4} as phase content regulator and TiCl{sub 3} as the titanium source. • The ratio of anatase and rutile were controlled by tuning ratio of C{sub 4}H{sub 6}O{sub 6} to TiCl{sub 3}. • The regulation degree could be further controlled by the concentration of NaCl. • The mixed-phase TiO{sub 2} exhibited higher activity than pure phase TiO{sub 2}.

  7. Microstructure, morphology and magnetic properties of Ni nanoparticles synthesized by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Bouremana, A. [LPM, Faculty of Sciences, USTHB, BP 32, El-Alia, Bab Ezzouar, Algiers (Algeria); Guittoum, A., E-mail: aguittoum@gmail.com [Nuclear Research Centre of Algiers, 02 Bd Frantz Fanon, BP 399, Alger-Gare, Algiers (Algeria); Hemmous, M. [Nuclear Research Centre of Algiers, 02 Bd Frantz Fanon, BP 399, Alger-Gare, Algiers (Algeria); Martínez-Blanco, D. [SCTs, University of Oviedo, EPM, 33600 Mieres (Spain); Gorria, Pedro [Department of Physics & IUTA, EPI, University of Oviedo, 33203 Gijón (Spain); Blanco, J.A. [Department of Physics, University of Oviedo, Calvo Sotelo St., 33007 Oviedo (Spain); Benrekaa, N. [LPM, Faculty of Sciences, USTHB, BP 32, El-Alia, Bab Ezzouar, Algiers (Algeria)

    2015-06-15

    Powder samples containing high purity nickel nanoparticles (NPs) were prepared by hydrothermal method from Ni(II) chloride hexahydrate (NiCl{sub 2}·6H{sub 2}O) under the presence of sodium hydroxide (NaOH) with different concentrations between 5 and 25 mol/L. The synthesis of the NPs occurs through chemical reduction at relatively low temperature (140 °C). The Ni NPs have a face-centred cubic (fcc) crystal structure with a lattice parameter value close to that of pure Ni (a = 3.52 Å). The average crystallite size determined from x-ray diffraction is around 20 nm, except for the sample synthesized under the highest NaOH concentration (25 mol/L), which has the largest average size (>30 nm). The powder morphology at the sub-micrometre length scale looks like agglomerates of Ni-NPs that drastically changes their shape depending on the NaOH concentration, from flower (5 mol/L) to a dendritic-like (25 mol/L). All the samples are ferromagnetic at room temperature with saturation magnetization values between 50 and 52emu/g, and a coercive field that increases with the NaOH concentration from around 135 (5 mol/L) up to 180Oe (25 mol/L). - Highlights: • Pure Nickel nanoparticles have been synthesized by a chemical reaction process. • Different morphologies were observed with the change of NaOH concentration. • The coercive field increases with increasing the NaOH concentration and depends on the shape of nanoparticles.

  8. Studies on ZnO Nanorods Synthesized by Hydrothermal Method and their Characterization

    Directory of Open Access Journals (Sweden)

    B.H. Soni

    2014-01-01

    Full Text Available ZnO nanorods, with a wide band gap of 3.37 eV have been attracting much attention due to its wide range of applications. Looking to this aspect in the present paper, ZnO nanorods were synthesized by hydrothermal method at 120 C for 2 hrs in an autoclave by using zinc acetate and sodium hydroxide as the starting materials. The final product obtained was then characterized by Energy Dispersive analysis of X-rays (EDAX, X-ray powder diffraction (XRD, transmission electron microscopy (TEM, selected area electron diffraction (SAED and Raman Spectroscopy. X-ray diffraction and Raman spectra showed that ZnO nanorods are belonging to wurtzite structure without any impurity phases. The ZnO nanorods shows polycrystalline behaviour as observed from SAED pattern and the calculated lattice parameters from this pattern which matches with the XRD results.The optical properties of the ZnO nanorods were then further studied with the help of absorption, photoluminescence (PL and FTIR spectra. The optical energy band gap determined from the absorption spectra comes about 3.33 eV. In the photoluminescence spectra of ZnO nanorods the UV emission appears at 380 nm and strong blue emission appears at 445 nm. FTIR spectra indicate the existence of distinct characteristic absorption peak at 520 cm – 1 for ZnO stretching modes. The potential toxicity of nanosized ZnO nanorods were investigated using Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, Serratia marceseus and Proteus vulgaris bacteria as test organism.

  9. Co3O4–ZnO hierarchical nanostructures by electrospinning and hydrothermal methods

    DEFF Research Database (Denmark)

    Kanjwal, Muzafar Ahmed; Sheikh, Faheem A.; Barakat, Nasser A.M.

    2011-01-01

    A new hierarchical nanostructure that consists of cobalt oxide (Co3O4) and zinc oxide (ZnO) was produced by the electrospinning process followed by a hydrothermal technique. First, electrospinning of a colloidal solution that consisted of zinc nanoparticles, cobalt acetate tetrahydrate and poly...

  10. 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.

  11. Resistive Switching Memory of TiO2 Nanowire Networks Grown on Ti Foil by a Single Hydrothermal Method

    Science.gov (United States)

    Xiao, Ming; Musselman, Kevin P.; Duley, Walter W.; Zhou, Norman Y.

    2017-04-01

    The resistive switching characteristics of TiO2 nanowire networks directly grown on Ti foil by a single-step hydrothermal technique are discussed in this paper. The Ti foil serves as the supply of Ti atoms for growth of the TiO2 nanowires, making the preparation straightforward. It also acts as a bottom electrode for the device. A top Al electrode was fabricated by e-beam evaporation process. The Al/TiO2 nanowire networks/Ti device fabricated in this way displayed a highly repeatable and electroforming-free bipolar resistive behavior with retention for more than 104 s and an OFF/ON ratio of approximately 70. The switching mechanism of this Al/TiO2 nanowire networks/Ti device is suggested to arise from the migration of oxygen vacancies under applied electric field. This provides a facile way to obtain metal oxide nanowire-based ReRAM device in the future.

  12. The Scottish Structural Proteomics Facility: targets, methods and outputs

    DEFF Research Database (Denmark)

    Oke, Muse; Carter, Lester G; Johnson, Kenneth A;

    2010-01-01

    The Scottish Structural Proteomics Facility was funded to develop a laboratory scale approach to high throughput structure determination. The effort was successful in that over 40 structures were determined. These structures and the methods harnessed to obtain them are reported here. This report ...

  13. A facile and efficient method for hydroxylation of azabenzanthrone compounds

    Institute of Scientific and Technical Information of China (English)

    Fang Xian Ning; Xiang Weng; Shi Liang Huang; Li Jun Gu; Zhi Shu Huang; Lian Quan Gu

    2011-01-01

    A novel and facile method of introducing 4-hydroxyl group into the aromatic ring of azabenzanthrone compounds was carded out by reacting azabenzanthrone compounds with hydrazine hydrate or hydroxylamine hydrochloride and sodium hydroxide in diethylene glycol(DEG) solvent.The mechanism of reaction may involve an amino intermediate and follow a hydroxyl substitution process.

  14. 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.

  15. 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.

  16. 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.

  17. A green and facile hydrothermal approach for the synthesis of high-quality semi-conducting Sb2S3 thin films

    Science.gov (United States)

    Liu, Meng; Gong, Yongshuai; Li, Zhilin; Dou, Meiling; Wang, Feng

    2016-11-01

    High-quality semi-conducting antimony sulfide (Sb2S3) thin films were directly deposited on the indium tin oxide (ITO) substrates by a green and facile one-step approach based on a hydrothermal reaction and post-annealing process without any assistance of complexing agents. The obtained Sb2S3 films possessed a relatively ideal S/Sb atomic ratio and a compact and continuous surface as the grain size of Sb2S3 was increased by high temperature annealing. The Sb2S3 film annealed at 450 °C exhibited the improved optical and electrical performances, with a narrow band gap of 1.63 eV, an electrical resistivity of 1.3 × 104 Ω cm, a carrier concentration of 7.3 × 1013 cm-3 and a carrier mobility of 6.4 cm2 V-1 s-1. This environmentally friendly synthetic route is promising for the preparation of high-quality Sb2S3 films to be used as absorber layer materials for high-performance solar cells.

  18. Growth Mechanism of γ-MnS Nanorod-Arrays by Hydrothermal Method on Anodic Aluminum Oxide Template

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Jianming; Liu, Weifeng; Lv, Yong; Yao, Lianzeng [Chinese Academy of Science, Hefei, Anhui (China)

    2010-09-15

    Hydrothermal method is a general, low-cost and convenience method which was utilized for synthesis of nanomaterials. Our research group has reported that oriented MnS nanorods on anodic aluminum oxide template were synthesized under a hydrothermal condition and demonstrated the effect of precursor content on the morphology evolution of as-samples. In order to research the growth mechanism of the arrays, herein we synthesized MnS nanorod arrays by combination of anodic aluminum oxide template and hydrothermal method on different substrates. Through-hole anodic aluminum oxide templates were prepared using Al foil (99.999%) via a two-step anodization process as described in literature. To investigate the effect of different substrates on the morphology of the-products, different substrates including anodic aluminum oxide template (sample A), one-step anodization Al foil (sample B, which was prepared by first anodizing Al foil for 10h and then removing the alumina layer with the mixed acid (0.6 M H{sub 3}PO{sub 4} and 0.15 M H{sub 2}CrO{sub 4}), where the foil still kept the close-packed concave nano-pits consistently with the nanopole of anodic aluminum oxide template), Al foil (sample C, dipped in HNO{sub 3} solution and covered by a compact alumina layer), Si wafer (sample D) respectively were put into Teflon-lined stainless steel autoclaves of 20 mL capacity filled with 16 mL mixed solution consisting of 2 mol/L MnCl{sub 4} and 2 mol/L thiourea. We kept the reaction at 150 .deg. C for 20 h. When reactions completed the products were washed three times with distilled water and absolute ethanol, respectively. Then the products were dried in an oven at 60 .deg. C.

  19. Photocatalytic Degradation of Rhodamine B Dye with MWCNT/TiO2/C60 Composites by a Hydrothermal Method

    Institute of Scientific and Technical Information of China (English)

    SHI Xiaoliang; YANG Xingyong; WANG Shuwei; WANG Sheng; ZHANG Qiaoxin; WANG Yufu

    2011-01-01

    Multi-walled carbon nanotube (MWCNT)/TiO2/C60 composite catalysts were prepared by hydrothermal method. TiO2 was deposited on the MWCNT surface. Their photocatalytic activities for degradation of Rhodamine B dye were studied. X-ray diffraction, field emission transmission electron microscopy, ultraviolet-visible light absorption spectrum and photoluminescence spectrum were carried out to characterize the composite catalysts. The results indicated that MWCNTs and C6o could greatly enhance the photocatalytic activity of TiO2.

  20. Reduction of Tb4+ions in luminescent Y2O3:Tb nanorods prepared by microwave hydrothermal method

    Institute of Scientific and Technical Information of China (English)

    Jarosaw Kaszewski; Bartomiej S Witkowski; ukasz Wachnicki; Hanka Przybyliska; Bolesaw Kozankiewicz; Ewa Mijowska; Marek Godlewski

    2016-01-01

    Terbium doped yttrium oxide was prepared with the microwave hydrothermal method. The Y2O3:Tb nanomaterial crystal-lized as needle-like grains. Bright luminescence in the green region was observed. Significant luminescence intensity increase was obtained after thermal treatment. Reduction of terbium ions was observed after heating in the air atmosphere. Tb4+ions were found to be stabilized by crystal impurities. Hydroxyl species were found to have impact on vacancies elimination. The terbium ions were used as optical and magnetic indicator of the material properties.

  1. 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.

  2. Facile Hydrothermal Synthesis of VS2/Graphene Nanocomposites with Superior High-Rate Capability as Lithium-Ion Battery Cathodes.

    Science.gov (United States)

    Fang, Wenying; Zhao, Hongbin; Xie, Yanping; Fang, Jianhui; Xu, Jiaqiang; Chen, Zhongwei

    2015-06-17

    In this study, a facile one-pot process for the synthesis of hierarchical VS2/graphene nanosheets (VS2/GNS) composites based on the coincident interaction of VS2 and reduced graphene oxide (rGO) sheets in the presence of cetyltrimethylammonium bromide is developed for the first time. The nanocomposites possess a hierarchical structure of 50 nm VS2 sheets in thickness homogeneously anchored on graphene. The VS2/GNS nanocomposites exhibit an impressive high-rate capability and good cyclic stability as a cathode material for Li-ion batteries, which retain 89.3% of the initial capacity 180.1 mAh g(-1) after 200 cycles at 0.2 C. Even at 20 C, the composites still deliver a high capacity of 114.2 mAh g(-1) corresponding to 62% of the low-rate capacity. Expanded studies show that VS2/GNS, as an anode material, also has a good reversible performance with 528 mAh g(-1) capacity after 100 cycles at 200 mA g(-1). The excellent electrochemical performance of the composites for reversible Li+ storage should be attributed to the exceptional interaction between VS2 and GNS that enabled fast electron transport between graphene and VS2, facile Li-ion diffusion within the electrode. Moreover, GNS provides a topological and structural template for the nucleation and growth of two-dimensional VS2 nanosheets and acted as buffer matrix to relieve the volume expansion/contraction of VS2 during the electrochemical charge/discharge, facilitating improved cycling stability. The VS2/GNS composites may be promising electrode materials for the next generation of rechargeable lithium ion batteries.

  3. Effect of precursor concentration on the structural and optical properties of ZnO nanorods prepared by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Lestari, Amie [Pusat Teknologi Material BPPT, Gd. 224 Kawasan PUSPIPTEK Serpong, Tangerang Selatan 15310 (Indonesia); Departemen Fisika, FMIPA, Universitas Indonesia, Kampus UI Depok (Indonesia); Iwan, S. [Jurusan Fisika, Fakultas MIPA, Universitas Negeri Jakarta, Jl. Pemuda No. 10 Rawamangun, Jakarta 13220 (Indonesia); Departemen Fisika, FMIPA, Universitas Indonesia, Kampus UI Depok (Indonesia); Djuhana, Dede; Imawan, Cuk; Harmoko, Adhi; Fauzia, Vivi, E-mail: vivi@sci.ui.ac.id [Departemen Fisika, FMIPA, Universitas Indonesia, Kampus UI Depok (Indonesia)

    2016-04-19

    Zinc oxide (ZnO) nanorods has attractive properties for nanoscale optoelectronic applications, such as optical sensors, ultraviolet laser diodes, and photodetectors. ZnO nanorods, can be fabricated by simple and low cost chemical approach, such as hydrothermal method. In this method, the morphology, microstructure, optical and electrical properties of ZnO nanorods are highly determined by process parameters such as solvent, deposition time, deposition temperature as well as annealing condition. In this paper we report the fabrication of ZnO nanorods that were grown on transparent conducting indium tin oxide coated glass substrates. Initially, ZnO seed layers were deposited on heated substrates with temperature of 450 °C using ultrasonic spray pyrolysis method with frequency of 1.7 MHz and then grown by hydrothermal method with three different precursor concentrations, namely 0.02 M, 0.06 M, and 0.1 M. The surface morphology and structure were investigated by field emission scanning electron microscope (FESEM) and x-ray diffraction (XRD), while the optical properties were observed by photoluminescence (PL) and and UV VIS reflectance spectroscopy.

  4. A new method on hydrothermal scheduling optimization in electric power market

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The hydrothermal scheduling in the electric power market becomes difficult because of introducing competition and considering sorts of constraints. An augmented Lagrangian approach is adopted to solve the problem, which adds to the standard Lagrangian function a quadratic penalty term without changing its dual property, and reduces the oscillation in iterations. According to the theory of large system coordination and decomposition, the problem is divided into hydro sub-problem and thermal sub-problem, which are coordinated by updating the Lagrangian multipliers, then the optimal solution is obtained. Our results for a test system show that the augmented Lagrangian approach can make the problem converge into the optimal solution quickly.

  5. Novel hydrothermal method for effective doping of N and F into nano Titania for both, energy and environmental applications

    Energy Technology Data Exchange (ETDEWEB)

    Jyothi, M.S.; D’Souza Laveena, P.; Shwetharani, R.; Balakrishna, Geetha R., E-mail: geethabalakrishna@yahoo.co.in

    2016-02-15

    Highlights: • Novel method to synthesize N, F doped TiO{sub 2} via hydrothermal method is discussed. • Change in bandgap of TiO{sub 2} upon doping makes a photocatalyst visible active. • 94% of degradation of EtBr was achieved within a less time of 90 min. • The doped titania also showed good efficiency as photo anodic material for solar cell. - Abstract: A novel and an efficient hydrothermal method for the preparation of an effective doped titania photocatalyst is reported. The crystal phase, binding energy, elemental composition, morphology, optical and electronic structure analyses were done by various techniques. The doped titania proved as an efficient electrode material and photocatalyst for solar cells and water treatment respectively. The photocatalyst is able to degrade the most potent mutagen ethidium bromide under sunlight with an enhancement of 1.6 times over its undoped analogue. As photo-anode material, showed an improved open circuit potential and fill factor. The created electron states in the doped sample act as charge carrier traps suppressing recombination which later detraps the same to the surface of the catalyst causing enhanced interfacial charge transfer. Surface acidity caused by F induction and lowered band gap energy that can respond to visible light facilitates improved energy harvesting and energy transfer leading to better photo activity.

  6. Defect study of TiO{sub 2} nanorods grown by a hydrothermal method through photoluminescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Rajabi, M., E-mail: Rajabi_m1@yahoo.com [Institute of Advanced Materials and Renewable Energies, Iranian Research Organization for Science and Technology (IROST), Tehran 3353136846 (Iran, Islamic Republic of); Shogh, S.; Iraji zad, A. [Department of Physics, Sharif University of Technology, Tehran 1136511155 (Iran, Islamic Republic of)

    2015-01-15

    This paper describes the photoluminescence study of titanium dioxide (TiO{sub 2}) nanorods grown by a hydrothermal synthesis method on the surface of fluorine doped tin oxide (FTO) coated glass. The effects of growth conditions including: reaction time, precursor concentration and adding NaCl to hydrothermal solution on the structural and optical properties of productions are examined by using SEM, XRD, TEM and room temperature photoluminescence measurements. Also, the performance of the TiO{sub 2} nanorods as a photoanode of dye sensitized solar cells is investigated. The different excitation energies and intensities are chosen to verify the discrete electronic state of radiative recombination centers in nanorods. The photoluminescence studies show the profound effect of the excitation light energy and intensity on the emission spectra. The nanorods have extended emission spectra from UV to visible region. The near band edge emission is observed at 3.04±0.01 eV. Also, the spectra consist of high emission peaks around at 3.44 and 3.14 eV and other emissions at 2.90±0.01, 2.83±0.02, 2.70±0.01, 2.56, 2.36±0.03, 2.30±0.02, 2.03, and 1.66 eV. The photoluminescence study of TiO{sub 2} nanorods and photoconversion efficiency of dye sensitized solar cells indicate a correlation among some PL emission peaks, the aspect ratio and efficiency of photoanode based solar cells. - Highlights: • TiO{sub 2} nanorods were grown directly on fluorine doped tin oxide coated glass by a hydrothermal synthesis method. • The effect of adding NaCl to hydrothermal solution for limiting the diameter growth of nanorods was studied. • The radiative recombination processes were investigated by photoluminescence spectroscopy under different excitation energies and intensities. • The performance of TiO{sub 2} nanorods as photoanode of dye sensitized solar cells was examined. • A correlation among aspect ratio of nanorods, photovoltaic properties of dye sensitized solar cells and

  7. Photoactivity enhancement of Zn-doped CdWO{sub 4} prepared with a hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Song, Xu Chun, E-mail: songxuchunfj@163.com [Department of Chemistry, Fujian Normal University, Fuzhou 350007 (China); Cui, Xia [Department of Chemistry, Fujian Normal University, Fuzhou 350007 (China); Huang, Wan Zhen [Research Center of Analysis and Measurement, Zhejiang University of Technology, Hangzhou 310014 (China); Zhang, Yong [Hangzhou Area Military Representative Office, Hangzhou, 310011 (China); Yin, Hao Yong [Institute of Environmental Science and Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); Zheng, Yi Fan [Research Center of Analysis and Measurement, Zhejiang University of Technology, Hangzhou 310014 (China)

    2015-07-15

    Graphical abstract: - Highlights: • The zinc-doped CdWO{sub 4} photocatalyst was synthesized by a hydrothermal process. • The Zn-doped CdWO{sub 4} exhibited excellent photocatalytic efficiency. • Zinc effect on photocatalytic activity and photodegradation mechanism were investigated. - Abstract: The zinc-doped CdWO{sub 4} photocatalyst was successfully synthesized by a hydrothermal process. The influences of zinc doping on the phase structures, optical properties, morphologies and photocatalytic activities of the CdWO{sub 4} catalyst were investigated. The results showed that the zinc-doping can enhance the photocatalytic efficiency of CdWO{sub 4} with the highest activity obtained on the Zn-doped CdWO{sub 4} (Zn/Cd ratio of 0.1) for degradation of rhodamine B(RhB) under simulated solar light irradiation. The enhancement of photocatalytic activity may be attributed to the zinc doping which can change the band gap of the catalyst and subsequently inhibit the recombination of photogenerated electrons and holes.

  8. Electronic structure and magnetic properties of FeWO{sub 4} nanocrystals synthesized by the microwave-hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, M.A.P. [INCTMN-DQ-Universidade Federal de Sao Carlos, Sao Carlos, P.O. Box 676, 13565-905, SP (Brazil); Cavalcante, L.S., E-mail: laeciosc@bol.com.br [INCTMN-Universidade Estadual, Paulista, P.O. Box 355, 14801-907, Araraquara, SP (Brazil); Morilla-Santos, C.; Filho, P.N. Lisboa [MAv-Universidade Estadual, Paulista, P.O. Box 473, 17033-360, Bauru, SP (Brazil); Beltran, A.; Andres, J.; Gracia, L. [Department de Quimica Fisica i Analitica, Universitat Jaume I, E-12071 Castello (Spain); Longo, E. [INCTMN-DQ-Universidade Federal de Sao Carlos, Sao Carlos, P.O. Box 676, 13565-905, SP (Brazil); INCTMN-Universidade Estadual, Paulista, P.O. Box 355, 14801-907, Araraquara, SP (Brazil)

    2012-11-15

    This communication reports that FeWO{sub 4} nanocrystals were successfully synthesized by the microwave-hydrothermal method at 443 K for 1 h. The structure and shape of these nanocrystals were characterized by X-ray diffraction, Rietveld refinement, and transmission electron microscopy. The experimental results and first principles calculations were combined to explain the electronic structure and magnetic properties. Experimental data were obtained by magnetization measurements for different applied magnetic fields. Theoretical calculations revealed that magnetic properties of FeWO{sub 4} nanocrystals can be assigned to two magnetic orderings with parallel or antiparallel spins in adjacent chains. These factors are crucial to understanding of competition between ferro- and antiferromagnetic behavior. Highlights: Black-Right-Pointing-Pointer Monophasic FeWO{sub 4} nanocrystals were synthesized by the microwave-hydrothermal method. Black-Right-Pointing-Pointer Rietveld refinement and clusters model for monoclinic structure Black-Right-Pointing-Pointer Magnetic properties of FeWO{sub 4} nanocrystals at different temperatures.

  9. 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.

  10. Fabrication and characterization of ZnO nanorods on polished titanium substrate using electrochemical–hydrothermal methods

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, Yih-Min [WuFeng University No. 117, Sec 2, Chiankuo Rd, Minhsiung, Chiayi County 62153, Taiwan, ROC (China); Chen, Hsiang, E-mail: hchen@ncnu.edu.tw [National Chi Nan University No. 1 University Road, Puli, Nantou County 54561, Taiwan, ROC (China)

    2013-10-01

    ZnO nanorods were deposited on the polished Ti substrate using electrochemical–hydrothermal methods. The titanium substrate was first electro-polished to remove the oxide and obtain an ideal flat surface. Subsequently, a seed layer of ZnO was electrochemically deposited in both Zn(NO{sub 3}){sub 2} and ZnCl{sub 2} solutions. On top of the seed layer, ZnO nanorods were hydrothermally deposited in Zn(NO{sub 3}){sub 2} and hexamethylenetetramine solution. To examine the polishing and growth conditions, atomic force microscope, X-ray diffraction analysis, and optical images under a microscope were used to measure the surface roughness, crystalline structure, and film morphology. Well-crystallized nanorods can be grown on top of the Ti substrate with a suitable polishing voltage and sufficient growth time. - Highlights: ► ZnO nanorods were fabricated with hydrothermal–electrochemical methods. ► The nanorods on the polished and unpolished Ti substrates were examined. ► The seed layers were electrodeposited in different solutions. ► Material and optical properties of the films were investigated.

  11. Experimental facility and void fraction calibration methods for impedance probes

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Fernando L. de; Rocha, Marcelo S., E-mail: floliveira@ipen.br, E-mail: msrocha@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    An experimental facility was designed and constructed with aims of to calibrate a capacitance probe for gas-liquid flow void fraction measurements. The facility is composed of a metallic hack with a vertical 2,300 mm high glass tube with 38 mm ID with stagnant water and compressed air bubbling system simulating the gas phase (vapor). At the lower part, a mixing section with a porous media element releases the air bubbles into the water, and the compressed air flow is measured by two calibrated rotameters. At the upper part a stagnant water tank separates the liquid and gas. Two pressure taps are located near the lower and upper sides of the glass tube for pressure difference measurement. The pressure difference is used for low void fraction values (0-15%) calibration methods, as described in the work. Two electrically controlled quick closing valves are installed between the porous media element and the upward separation tank for high void fraction values measurement (15-50%) used to calibrate the capacitance probe. The experimental facility design, construction, capacitance probe calibration methods and results, as well as flow pattern visualization, are presented. Finally, the capacitance probe will be installed on a natural circulation circuit mounted at the Nuclear Engineering Center (CEN/IPEN/CNEN-SP) for measurement of the instantaneous bulk void. Instantaneous signals generated by the capacitance probe will allow the determination of natural circulation loop global energy balance. (author)

  12. A comparative study on heat dissipation, morphological and magnetic properties of hyperthermia suitable nanoparticles prepared by co-precipitation and hydrothermal methods

    Indian Academy of Sciences (India)

    Md Shariful Islam; Yoshihumi Kusumoto; Junichi Kurawaki; Md Abdulla-Al-Mamun; Hirotaka Manaka

    2012-12-01

    Magnetite (Fe3O4) nanoparticles were prepared by co-precipitation and hydrothermal methods and their phase transfer was done successfully to compare their performances in different aspects. Synthesized nanoparticles were characterized for XRD, FE–SEM, TEM, UV-Vis absorption (reflectance) spectra, magnetic hysteresis loops and a.c. magnetic field induced hyperthermia. The magnetic nanoparticles prepared by the co-precipitation method show superior performances in respect of heat dissipation capability, saturation of magnetization values and particle size when compared to those prepared by the hydrothermal method.

  13. Synthesis and electrochemical performance of LiCoPO4 micron-rods by dispersant-aided hydrothermal method for lithium ion batteries

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yujuan; WANG Suijun; ZHAO Chunsong; XIA Dingguo

    2009-01-01

    LiCoPO4 micron-rods with an average diameter of about 500 nm and length of about 5 μm were synthesized by dispersant-aided hydrother mal method. Poly(n-vinylpyrrolidone) (PVP) was used as dispersant in the hydrothermal method. The starting solution and the concentration of dispersant have significant influences on the morphology of LiCoPO4, and the electrochemical performance is improved via controlling the particle size and morphology by the hydrothermal method. The cell using smaller particle LiCoPO4 as cathode delivers a larger capacity and lower cell polarization.

  14. New methods of researching healthcare facility users: the nursing workspace

    Directory of Open Access Journals (Sweden)

    Karen Keddy

    2012-10-01

    Full Text Available This study is entitled Embodied Professionalism: The relationship between the physicalnature of nursing work and nursing space. The analysis is based in a critical examination of existing approaches, assumptions, and attitudes in the research literature about who, what, and how to study the person-environment relationship in healthcare facilities. New methods of studying how nurses experience their work, their workplace and the objects in their workspace are needed in order to address important issues of this person-environment relationship. Nursing work is re-conceptualized asembodied professionalism which acknowledges the interconnections between the physical labor ofprofessional nursing work, time, and space. This is a qualitative case study of nursing activities on a surgical unit that are invisible, marginalized, and unaccounted for in the research literature. Instead of studying how nurses’ efficiency and productivity could be increased through design interventions, this study examines the physical nature of nursing work and the physical setting from the nurses’ perspective. Instead of viewing the healthcare facility as solely a place for healing, this approach views the healthcare facility as a place for working. A nurse’s goal can simply be the desire to ‘get the workdone.’ A qualitative research methodology and a mixed method approach is used in this study. The methods include structured interviews, location mapping, photo-documentation, architectural inventories, place-centered behavioral mapping, and focused observations. In order to get a better understanding of how nurses experience their workspace, an image-based visual research method, theexperiential collage, was designed. The findings from using these methods reveal the significant rolethat the physical activities of moving, searching, and recovering play in gaining insights into nurses’ socio-spatial experience of the nursing workspace.

  15. Effects of hydrothermal annealing on characteristics of CuInS{sub 2} thin films by SILAR method

    Energy Technology Data Exchange (ETDEWEB)

    Shi Yong, E-mail: sys-99@163.com [Key Laboratory of Industrial Ecology and Environmental Engineering and State Key Laboratory of Fine Chemical, School of Environmental Sciences and Technology, Dalian University of Technology, Dalian 116024 (China); Xue Fanghong [Key Laboratory of Industrial Ecology and Environmental Engineering and State Key Laboratory of Fine Chemical, School of Environmental Sciences and Technology, Dalian University of Technology, Dalian 116024 (China); Li Chunyan [School of Materials, Dalian University of Technology, Dalian 116024 (China); Zhao Qidong; Qu Zhenping; Li Xinyong [Key Laboratory of Industrial Ecology and Environmental Engineering and State Key Laboratory of Fine Chemical, School of Environmental Sciences and Technology, Dalian University of Technology, Dalian 116024 (China)

    2012-07-15

    CuInS{sub 2} thin films have been deposited by successive ionic layer absorption and reaction (SILAR) method, then annealed in a Na{sub 2}S solution (denoted as hydrothermal annealing) at 200 Degree-Sign C for different time. The effect of hydrothermal annealing on the properties of the films was studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and optical absorption spectroscopy. The XRD, TEM and SEM results indicate that well-crystallized CuInS{sub 2} films could be obtained after annealing in 0.1 mol/L Na{sub 2}S solution for 1.5 h. The annealed CuInS{sub 2} films were slightly S-rich and the direct band gap varied from 1.32 to 1.58 eV as the annealing time increased from 0.5 h to 2 h.

  16. Preparation of perpendicular oriented TiO2 films via hydrothermal method: phase selection and growth control

    Science.gov (United States)

    Gao, Yun; Guo, Meilan; Xia, Xiaohong; Shao, Guosheng

    2013-03-01

    Either rutile or anatase vertical orientated TiO2 array films were synthesized successfully on FTO (F: SnO2) substrate via hydrothermal method through controlling the concentration of Cl- and SO42- . The density of nanorods can be adjusted by varying the volume ratio of ethanol/water, and the degree of orientation and crystallinity of TiO2 nanofilms were enhanced with increasing dosage of ethanol. Meanwhile, completely dense anatase films with [004] oriented growth appear within a very narrow concentration window when adding sulfuric acid into precursor. Besides, other alcohols such as methanol, n-propanol and n-butyl were also used as solvent to examine the role of alcohol type during hydrothermal process for both two phase films. The growth rate and degree of perpendicular orientation declined as the alkyl length of solvents increases. Hydrogen sensing characteristics of dense films of both rutile and anatase phases showed that there was a remarkable improvement of sensitivity response over reported data. It was found that rutile films have higher sensitivity while anatase films have faster response. This work is supported by Ministry of Education of China (211108) and Science and Technology of Wuhan (2010CDA024, 201110821251).

  17. Characterization and adsorption performance of Pb(II) on CuO nanorods synthesized by the hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Arfaoui, Lobna; Kouass, Salah [Laboratoire des matériaux utiles, Institut National de Recherche et d' Analyse Physico-Chimique (INRAP) Sidi Thabet, 2020 Tunis (Tunisia); Dhaouadi, Hassouna, E-mail: dhaouadihassouna@yahoo.fr [Laboratoire Matériaux Traitement et Analyse, Institut National de Recherche et d' Analyse Physico-Chimique (INRAP) Sidi Thabet, 2020 Tunis (Tunisia); Jebali, Raouf [Laboratoire des matériaux utiles, Institut National de Recherche et d' Analyse Physico-Chimique (INRAP) Sidi Thabet, 2020 Tunis (Tunisia); Touati, Fathi [Laboratoire Matériaux Traitement et Analyse, Institut National de Recherche et d' Analyse Physico-Chimique (INRAP) Sidi Thabet, 2020 Tunis (Tunisia)

    2015-10-15

    Highlights: • The nanorods of CuO were synthesized by a hydrothermal route without any surfactant. • X-ray diffraction showed monoclinic structure with space group C{sub 2/c}. • The nanorods show relatively high adsorption capacity for the removal of Pb(II). • The adsorption kinetics could be fitted well by the pseudo-second-order model. • The equilibrium data can be fitted well using the Langmuir isotherm model - Abstract: Copper oxide (CuO) nanorods were synthesized by hydrothermal method. The detailed structural, compositional and optical characterization of this material was also evaluated with XRD, FT-IR, EDS, and UV–vis spectroscopy, which confirmed that the obtained nanorods are well-crystallized CuO and possess good optical properties. SEM and TEM studies revealed that the as-synthesized CuO nanorods are uniform with an average diameter of 17 nm. The adsorption activity of the CuO nanostructures was studied. The adsorption results showed that the CuO nanorods are an effective and efficient adsorbent for the removal of Pb(II) ions. The influence of various operational parameters such as the pH of the solution, the contact time and the initial concentrations were also studied and the results were discussed. The estimated maximum lead ion adsorption capacity of the CuO nanorods was found to be 188.67 mg g{sup −1} at an optimum pH of 6.

  18. Methods for sulfate removal in liquid-phase catalytic hydrothermal gasification of biomass

    Science.gov (United States)

    Elliott, Douglas C; Oyler, James

    2013-12-17

    Processing of wet biomass feedstock by liquid-phase catalytic hydrothermal gasification must address catalyst fouling and poisoning. One solution can involve heating the wet biomass with a heating unit to a pre-treatment temperature sufficient for organic constituents in the feedstock to decompose, for precipitates of inorganic wastes to form, for preheating the wet feedstock in preparation for subsequent removal of soluble sulfate contaminants, or combinations thereof. Processing further includes reacting the soluble sulfate contaminants with cations present in the feedstock material to yield a sulfate-containing precipitate and separating the inorganic precipitates and/or the sulfate-containing precipitates out of the wet feedstock. Having removed much of the inorganic wastes and the sulfate contaminants that can cause poisoning and fouling, the wet biomass feedstock can be exposed to the heterogenous catalyst for gasification.

  19. CO2 Reforming of CH4 over Ni/CeO2-ZrO2-Al2O3 Prepared by Hydrothermal Synthesis Method

    Institute of Scientific and Technical Information of China (English)

    Chunlin Li; Yilu Fu; Guozhu Bian; Tiandou Hu; Yaning Xie; Jing Zhan

    2003-01-01

    The Ni/CeO2-ZrO2-Al2O3 catalyst with different Al2O3 and NiO contents were prepared by hydrothermal synthesis method. The catalytic performance for CO2 reforming of CH4 reaction, the interaction among components and the relation between Ni content and catalyst surface basicity were investigated. Results show that the interaction between NiO and Al2O3 is stronger than that between NiO and CeO2-ZrO2. The addition of Al2O3 can prevent the formation of large metallic Ni ensembles, increase the dispersion of Ni, and improve catalytic activity, but excess Al2O3 causes the catalyst to deactivate easily. The interaction between NiO and CeO2 results in more facile reduction of surface CeO2. The existence of a small amount of metallic Ni can increase the number of basic sites. As metallic Ni may preferentially reside on the strong basic sites, increasing Ni content can weaken the catalyst basicity.

  20. Effects of Mn dope on morphological, structural and optical properties of ZnO nanorods grown by a hydrothermal method

    Science.gov (United States)

    Putri, N. A.; Febrianti, Y.; Sugihartono, I.; Fauzia, V.; Handoko, D.

    2017-07-01

    ZnO nanorods were grown on glass substrate has been systematically investigated by varying Mn doping concentrations. The nanorods have been developed by a simple hydrothermal method on the ZnO seed layers which were deposited by ultrasonic spray pyrolysis method. The influences of Mn on the morphological, structural and optical behavior were observed by measuring Scanning Electron Microscope, X-Ray Diffraction, and UV-Vis spectrophotometer, respectively. It is found that the nanorods growth without any orientation. Interestingly, all the nanorods under investigated exhibit a polycrystalline hexagonal wurtzite structure with strong absorption in UV region and a high transparency in the visible region suggesting that optical properties of ZnO nanorods have been modified by Mn doping.

  1. 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.

  2. Synthesis of lead-free piezoelectric powders by ultrasonic-assisted hydrothermal method and properties of sintered (K0.48Na0.52)NBO3 ceramics.

    Science.gov (United States)

    Isobe, Gaku; Maeda, Takafumi; Bornmann, Peter; Hemsel, Tobias; Morita, Takeshi

    2014-02-01

    (K,Na)NbO3 ceramics have attracted much attention as lead-free piezoelectric materials with high piezoelectric properties. High-quality (K,Na)NbO3 ceramics can be sintered using KNbO3 and NaNbO3 powders synthesized by a hydrothermal method. In this study, to enhance the quality factor of the ceramics, high-power ultrasonic irradiation was employed during the hydrothermal method, which led to a reduction in the particle size of the resultant powders.

  3. Optical and morphological properties of ZnO- and TiO2-derived nanostructures synthesized via a microwave-assisted hydrothermal method

    CSIR Research Space (South Africa)

    Moloto, N

    2012-01-01

    Full Text Available A microwave-assisted hydrothermal method was used to synthesize ZnO and TiO2 nanostructures. The experimental results show that the method resulted in crystalline monodispersed ZnO nanorods that have pointed tips with hexagonal crystal phase. TiO2...

  4. Effect of organic additives on characteristics of carbon-coated LiCoPO4 synthesized by hydrothermal method

    Science.gov (United States)

    Maeyoshi, Yuta; Miyamoto, Shohei; Noda, Yusaku; Munakata, Hirokazu; Kanamura, Kiyoshi

    2017-01-01

    Carbon-coated LiCoPO4 particles are synthesized by one-pot hydrothermal process using three different organic additives (carboxymethylcellulose sodium salt (CMC), glucose, and ascorbic acid). The effect of the organic additives on particle size, morphology, nature of carbon coating, and electrochemical property of the resulting LiCoPO4 is investigated. CMC plays important roles to decrease the particle size and form well-covered carbon coating on the surface. Carbon-coated LiCoPO4 prepared using CMC delivers higher initial discharge capacity of 135 mA h g-1 at 0.1 C, and shows superior rate capability and cyclic performance than the other samples. The improved electrochemical characteristics are attributed to not only the fine particle which allows facile electronic and ionic transport, but also the high coverage of carbon coating which improves the electrical conductivity and prevents the irreversible reactions of the charged LiCoPO4 with electrolyte.

  5. 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.

  6. 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.

  7. Magnetic and Structural Properties of Cobalt- and Zinc-Substituted Nickel Ferrite Synthesized by Microwave-Assisted Hydrothermal Method

    Science.gov (United States)

    Sinfrônio, F. S. M.; Santana, P. Y. C.; Coelho, S. F. N.; Silva, F. C.; de Menezes, A. S.; Sharma, S. K.

    2017-02-01

    Ceramic spinel-based ferrites of cobalt, nickel and zinc were prepared by means of the microwave-assisted hydrothermal method. All samples were thoroughly characterized using different techniques for their structural, compositional, phonic and magnetic properties. The Rietveld analysis of x-ray powder diffraction data revealed the crystallinity as well single-phase partially inverse spinel structure. Wavelength dispersive x-ray fluorescence measurement indicates a good correlation between the empirical stoichiometry. The estimated average crystallite size varies between 9 nm and 13 nm (XRPD) and 6 and 14 nm for high-resolution transmission electron microscopy measurements. In addition, the observed micro-strain varies in the range of 0.01-0.6%. All samples show a quasi-spherical morphology and slight agglomeration. Infrared and Raman data spectra exhibit characteristic modes for spinel-based ferrites. Direct current magnetic measurements indicate behavior typical of magnetically soft materials system at 300 K.

  8. Carbon/Clay nanostructured composite obtained by hydrothermal method; Compositos nanoestruturados carbono/argila obtidos por metodo hidotermico

    Energy Technology Data Exchange (ETDEWEB)

    Barin, G.B.; Bispo, T.S.; Gimenez, I.F.; Barreto, L.S., E-mail: gabriela.borin@gmail.co [Universidade Federal de Sergipe (UFS), Aracaju, SE (Brazil). Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais; Souza Filho, A.G. [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil). Dept. de Fisica

    2010-07-01

    The development of strategies for converting biomass into useful materials, more efficient energy carrier and / or hydrogen storage is shown a key issue for the present and future. Carbon nanostructure can be obtained by severe processing techniques such as arc discharge, chemical deposition and catalyzed pyrolysis of organic compounds. In this study we used hydrothermal methods for obtaining nanostructured composites of carbon / clay. To this end, we used coir dust and special clays. The samples were characterized by infrared spectroscopy, X-ray diffraction and Raman. The presence of the D band at 1350 cm{sup -1} in the Raman spectrum shows the formation of amorphous carbon with particle size of about 8.85 nm. (author)

  9. Enhanced Visible-Light Photocatalytic Activity of C/Ce-Codoped ZnO Nanoellipsoids Synthesized by Hydrothermal Method

    Science.gov (United States)

    Ha, Luu Thi Viet; Dai, Luu Minh; Nhiem, Dao Ngoc; Van Cuong, Nguyen

    2016-08-01

    C/Ce-codoped ZnO nanomaterial has been synthesized by a hydrothermal method and its physical properties and characterization investigated using thermogravimetric and differential thermal analysis (TG-DTA), x-ray diffraction (XRD) analysis, Fourier-transform infrared (FTIR) spectroscopy, energy-dispersive x-ray (EDX) spectroscopy, UV-Vis diffuse reflectance spectroscopy, and scanning electron microscopy (SEM). The photocatalytic activity of the nanomaterial was examined using methylene blue as organic dye under visible-light source. The results show that the C/Ce-codoped ZnO nanomaterial exhibited higher photocatalytic activity under visible-light irradiation compared with undoped ZnO, Ce-doped ZnO or C-doped ZnO nanomaterials. Such enhancement of the photocatalytic activity of C/Ce-codoped ZnO under visible-light irradiation suggests that these nanoparticles might have good applications in optoelectronics and wastewater treatment.

  10. 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.

  11. Development of a hydrothermal method to synthesize spherical ZnSe nanoparticles: Appropriate templates for hollow nanostructures

    Directory of Open Access Journals (Sweden)

    S. Gharibe

    2014-01-01

    Full Text Available Hydrothermal method was used to synthesize pure ZnSe nanosphere materials. The effects of the reducing agent amount, the reaction time and temperature were investigated on the purity of ZnSe. Also, the effects of surfactants such as sodium dodecyl sulfate (SDS (anionic and cetyl trimethylammonium bromide (CTAB (cationic were studied on the morphology of ZnSe. The prepared nanospheres were characterized using XRD, SEM, TEM and UV-Vis spectroscopy. Through these techniques, it was found that the pure ZnSe nanoparticles have a zinc blend structure and in a spherical form with average diameter of 30 nm. DOI: http://dx.doi.org/10.4314/bcse.v28i1.5

  12. The directed preparation of TiO2 nanotubes film on FTO substrate via hydrothermal method for gas sensing application

    Directory of Open Access Journals (Sweden)

    Pham Van Viet

    2016-04-01

    Full Text Available In this research, we directly synthesized TiO2 nanotubes film on Fluorine doped Tin oxide (FTO substrate via hydrothermal method from commercial TiO2 in NaOH solution at 135 ℃ for 24 hours. The samples were characterized by X-ray diffraction (XRD pattern, field emission scanning electron microscopy (FESEM and transmitting electron microscopy (TEM. The average diameter of TiO2 nanotubes (TNTs is about 10–12 nm and their length is about a few hundred nanometers. The sensitivity ability of TNTs increases as the gas concentration increases and developing to the highest sensitivity of TNTs is 2.4 at 700 ppm of the ethanol concentration. The same as the gas concentration, the sensitivity of TNTs increases when the temperature increases. Besides, the sensitivity of samples at 250 ℃ is doubled compared to samples determined at 100 ℃.

  13. Carbon/Clay nanostructured composite obtained by hydrothermal method; Compositos nanoestruturados carbono/argila obtidos por metodo hidotermico

    Energy Technology Data Exchange (ETDEWEB)

    Barin, G.B.; Bispo, T.S.; Gimenez, I.F.; Barreto, L.S., E-mail: gabriela.borin@gmail.co [Universidade Federal de Sergipe (UFS), Aracaju, SE (Brazil). Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais; Souza Filho, A.G. [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil). Dept. de Fisica

    2010-07-01

    The development of strategies for converting biomass into useful materials, more efficient energy carrier and / or hydrogen storage is shown a key issue for the present and future. Carbon nanostructure can be obtained by severe processing techniques such as arc discharge, chemical deposition and catalyzed pyrolysis of organic compounds. In this study we used hydrothermal methods for obtaining nanostructured composites of carbon / clay. To this end, we used coir dust and special clays. The samples were characterized by infrared spectroscopy, X-ray diffraction and Raman. The presence of the D band at 1350 cm{sup -1} in the Raman spectrum shows the formation of amorphous carbon with particle size of about 8.85 nm. (author)

  14. Mechanochemical Effects on the Synthesis of Copper Orthophosphate and cyclo-Tetraphosphate Bulks by the Hydrothermal Hot Pressing Method

    Directory of Open Access Journals (Sweden)

    Isao Tanaka

    2009-01-01

    Full Text Available Copper orthophosphate, Cu3(PO42, and cyclo-tetraphosphates, Cu2P4O12, were synthesized using phosphoric acid and basic copper carbonate, and then treated with a planetary mill for up to 360 minutes. The un-milled and milled samples were characterized by X-ray diffraction (XRD and Fourier transform infrared (FT-IR spectroscopy. SEM images, particle size distribution, specific surface area, UV-Vis reflectance spectra were also used to evaluate the materials. The un-milled and milled materials were used to fabricate copper phosphate bulks by a hydrothermal hot pressing method. The influence of powder condition on the sintering behavior of the copper phosphates was studied.

  15. Temperature and reaction time effects on the structural properties of titanium dioxide nanopowders obtained via the hydrothermal method

    Directory of Open Access Journals (Sweden)

    G. C. Collazzo

    2011-06-01

    Full Text Available An investigation was carried out on the synthesis of titanium dioxide nanopowders via the hydrothermal method, examining the influence of temperature (150ºC and 200ºC and reaction time (6 to 36 h. The resulting powders were characterized by X-ray diffraction, infrared absorption spectrophotometry, transmission electron micrographs and surface area. The X-ray diffraction revealed that there was formation of a pure crystalline phase, consisting only of anatase for all conditions of synthesis. Both temperature and reaction time proved to have a slight influence on the crystallite size (from 9 to 17 nm and a significant influence on the surface area (from 86 to 168 m².g-1.

  16. Morphology and magnetic properties of α-Fe2O3 particles prepared by octadecylamine-assisted hydrothermal method

    Institute of Scientific and Technical Information of China (English)

    Zhong Liu; Baoliang Lv; Dong Wu; Yuhan Sun

    2012-01-01

    α-Fe2O3 particles with various morphologies,including micro-doublesphere,tetrakaidecahedron and nanoparticles-aggregated micro-ellipsoid,were successfully synthesized via an octadecylamine-assisted hydrothermal method.The products were characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM).The results indicate that the presence of octadecylamine played a crucial role in morphology evolution by selective crystal adsorption,The protonated octadecylamine increased the pH value that accelerated nucleation,and the long alkyl groups of octadecylamine acted as an adsorption inhibitor to retard the growth of nanoparticles.The as-prepared α-Fe2O3 particles exhibited higher remanent magnetization and coercivity than other α-Fe2O3 particles of similar size.These properties should be attributed to the superstructure and the shape anisotropy of the synthesized particles.

  17. 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.

  18. Preparation and characterization of ZnO/ZnS hybrid photocatalysts via microwave-hydrothermal method

    Institute of Scientific and Technical Information of China (English)

    Jinglian ZHAO; Liang ZHAO; Xinping WANG

    2008-01-01

    The photocatalytic performance of ZnO/ZnS hybrid nanocomposite was largely higher than that of the mere ZnO or ZnS nanoparticles, but the complicated procedure and misdistribution of final products limited its large-scale productions. The exploration of a novel syn-thesis route of ZnO/ZnS hybrid photocatalysts with high catalytic performance is becoming a crucial step for the large-scale application of ZnO/ZnS hybrid photocatalytic technique. Preparation and characterization of nanosized ZnO/ZnS hybrid photocatalysts were studied in this paper. The photocatalysts were obtained via microwave-hydrothermal crystallization with the help of sodium cit-rate. The products were characterized by X-ray diffrac-tion (XRD), transmission electron microscopy (TEM), particle size distribution (PSD), and Fourier transformed infrared spectroscopy (FT-IR). The results indicated that so-synthesized ZnO/ZnS samples consisted of the high pure cubic (sphalerite) ZnS and hexagonal ZnO nanocrys-tallines with a narrow particle size distribution. The pos-sible formation mechanisms of ZnO/ZnS nanocrystallines were mainly attributed to the superficially protective effect of citrate. The photocatalytic experiments demon-strated that the ZnO/ZnS photocatalysts exhibited a higher catalytic activity for the degradation of acid fuchs-ine than other monocomponents.

  19. Fabrication and Magnetic Properties of Sn-Doped ZnO Microstructures via Hydrothermal Method.

    Science.gov (United States)

    Farooq, M Hassan; Hussain, Riaz; Iqbal, M Zubair; Shah, M W; Rana, Usman Ali; Khan, Salah Ud-Din

    2016-01-01

    Pure zinc oxide (ZnO) and Sn-doped ZnO hexagonal sheets were synthesized by template free hydrothermal growth mechanism with controlled morphology by using zinc acetate dihydrate (Zn(CH₃COO)₂· 2H₂O), tin chloride pentahydrate (SnCl₄ · 5H₂O), Polyvinylpyrrolidone (PVP) and H₂O as precursors. The structural, physical, chemical, and magnetic characteristics were investigated by X-ray diffraction, field-emission scanning electron microscopy, energy dispersive X-ray spectroscopy and alternating gradient magnetometer (AGM), respectively. The average crystalline size of hexagonal phase of ZnO sheets was calculated to be about 34 nm from XRD patterns. Energy dispersive spectroscopy provided the compositional analysis of pure and Sn-doped ZnO. Room temperature ferromagnetism (RTFM) was observed by AGM for pure and Sn-doped ZnO hexagonal plates. RTFM increases monotonically for Sn doping and reaches maximum saturation magnetization 0.045 emu/g for 3% Sn-doped ZnO.

  20. Electronic microscopy analysis of HAP single crystals prepared by hydrothermal method

    Institute of Scientific and Technical Information of China (English)

    王友法; 闫玉华; 李美娟; 张宏泉

    2003-01-01

    H ydroxyapatite(HAP, Ca10 (PO4)6 (OH)2) is one of the quite important bone implant materials. Thehydroxyapatite crystals were synthesized under hydrothermal condition. The specimen was verified to be HAP crys-tal by the X-ray powder diffractometry(XRD). Then the specimen was distinguished single crystal from polycrystalby the use of the transmission electron microscope(TEM). The diffraction pattern of the specimen is neatly arrangeddiffraction spots, that verified the crystals were single crystals. The interplanar distance d calculated from diffrac-tion spot is coincided with that of HAP's JCPDS card. Moreover, crystal face angles calculated from crystal face in-dex are coincided with the values by measuring on the pattern. The HAP crystals are needle-like in shape with about3 μm in diameter and 180 μm in length. Most of the crystals are separate whiskers. Their length/diameter ratio ran-ges from 40 to 100. The average ratio is about 60.

  1. Synthesis and optical characteristics of yttrium-doped zinc oxide nanorod arrays grown by hydrothermal method.

    Science.gov (United States)

    Park, Hyunggil; Kim, Younggyu; Ji, Iksoo; Lee, Sang-Heon; Kim, Jin Soo; Kim, Jin Soo; Leem, Jae-Young

    2014-11-01

    Yttrium-doped ZnO (YZO) nanorods were synthesized by hydrothermal growth on a quartz substrate with various post-annealing temperatures. To investigate the effects of post-annealing on the optical properties and parameters of the nanorods, X-ray diffractometry (XRD), photoluminescence (PL) measurement, and ultraviolet (UV)-visible spectroscopy were used. From the XRD investigation, the full width at half maximum (FWHM) and the dislocation density of the nanorods was found to increase with an increase in the post-annealing temperature. In the PL spectra, the intensity of the near band edge (NBE) emission peak in the UV region also increases with an increase in the temperature of post-annealing. The deep level emission (DLE) peak in the visible region changes with various post-annealing temperatures, and its intensity increases remarkably with post-annealing at 800 degrees C. In this paper, changes in the optical parameters of the nanorods caused by variation in the behavior of Y during post-annealing was investigated, with properties such as absorption coefficients, refractive indices, and dispersion parameters being obtained from transmittance and reflectance analysis.

  2. 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).

  3. 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.

  4. Preparation and electrochemical performance of nanosized Co3O4 via hydrothermal method

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The hydrotalcite-type cobalt compounds were prepared through oxidation of Co(OH)2 gel using NH4OH as precipitating agent and H2O2 as oxidant. These hydrotalcite-type cobalt compounds were transformed into Co3O4 through hydrothermal decomposition with nanostructural deformation. The precursor and product were characterized by Fourier-transform infrared(FT-IR)spectrum, X-ray diffractometry(XRD) and transmission electron microscopy(TEM). The electrochemical performances of as-prepared nanosized Co3O4 as anode materials in lithium-ion batteries were tested by charge-discharge test in the voltage range of 0-3.0 V. The influence of morphology of Co3O4 particle on the capacity and cycling performance was studied. The results show that the shape and size of the final product can be controlled by altering cobalt sources. The irregular cubic Co3O4 with the average particle size of about 10 nm shows the best electrochemical performance. After 10 charge-discharge cycles, the specific charge capacity retains 555 mA·h/g.

  5. Facile hydrothermal synthesis and characterization of Co2GeO4/r-GO@C ternary nanocomposite as negative electrode for Li-ion batteries.

    Science.gov (United States)

    Subramanian, Yuvaraj; Kaliyappan, Karthikeyan; Ramakrishnan, Kalai Selvan

    2017-07-15

    Ternary nanocomposite of Co2GeO4/r-GO@C is synthesized by single step hydrothermal method followed by calcination. The XRD analysis reveals the formation of cubic structured Co2GeO4 and their corresponding functional groups identified through Raman analysis. The TEM analysis assures that uniform distribution of Co2GeO4 nanoparticles on the r-GO layers. The Galvanostatic charge-discharge (GCD) curve demonstrates that the initial discharge capacity of pristine Co2GeO4, Co2GeO4/r-GO and Co2GeO4/r-GO@C composite is 1400, 1284 and 1594mAhg(-1) at 50mAg(-1), respectively. The cycling stability curve shows the specific capacity of 609, 970 and 1180mAhg(-1) for pristine, Co2GeO4/r-GO and Co2GeO4/r-GO@C composite, respectively over 15 cycles. The ternary composite of Co2GeO4/r-GO@C delivers the discharge capacity of 323mAhg(-1) at high current density of 1Ag(-1) over 500 cycles with capacity retention of 71%. The rate capability curve indicates that Co2GeO4/r-GO@C composite shows the better rate capability. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Facile hydrothermal synthesis of cubic spinel AB2O4 type MnFe2O4 nanocrystallites and their electrochemical performance

    Science.gov (United States)

    Kwon, JongMyeong; Kim, Jae-Hong; Kang, Soon-Hyung; Choi, Cheol-Jong; Rajesh, John Anthuvan; Ahn, Kwang-Soon

    2017-08-01

    Cubic spinel MnFe2O4 nanoparticles were synthesized using a simple hydrothermal method followed by post-annealing. The effects of the reaction temperature on the crystallinity, morphology, and electrochemical performance were studied. The reaction temperature played an important role in the synthesis of highly crystalline MnFe2O4 nanoparticles. At low reaction temperatures (product contained a secondary inactive Fe2O3 phase as well as MnFe2O4 nanoparticles. In contrast, pure MnFe2O4 nanoparticles were obtained at temperatures above 180 °C. Furthermore, the crystallinity of the MnFe2O4 nanoparticles was enhanced significantly by increasing the reaction temperature to 200 °C. The cubic spinel MnFe2O4 nanoparticles synthesized at 200 °C delivered a maximum specific capacitance of 282.4 F g-1 at a current density of 0.5 A g-1 in a 2 M aqueous KOH solution, and exhibited long-term cyclic stability of 85.8% capacitance retention after 2000 cycles. This was attributed to the cubic spinel ferrite nanocrystallite particles not only providing the more active sites for OH- ion diffusion but also reducing the path lengths for OH- ion diffusion. These results show that the synthesized MnFe2O4 nanoparticles are promising candidates for pseudocapacitors and other electrochemical applications.

  7. 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.

  8. Preparation of highly dispersed W/Al2O3 hydrodesulfurization catalysts via a microwave hydrothermal method: Effect of oxalic acid

    Directory of Open Access Journals (Sweden)

    Hao Wang

    2016-01-01

    Full Text Available A novel microwave hydrothermal method was developed to prepare highly dispersed W/Al2O3 catalysts, in which WO3 was deposited on alumina via precipitation between tungstate and nitric acid under microwave hydrothermal environment and oxalic acid was used as an additive. Moreover, the role of oxalic acid was investigated by varying its amount and the addition method. It is found that the catalysts show higher WO3 dispersion and weaker W–Al interaction than that prepared by the conventional impregnation method. The hydrothermal period can be extremely reduced to a few minutes, and highly dispersed WO3 can be achieved even without oxalic acid. When oxalic acid was added after the formation of H2WO4, it mainly acts as a modifier for reacting with the hydroxyl groups on alumina and has little effect on WO3 dispersion. When oxalic acid was divided into two parts, one for pretreating alumina and the remains for preventing the aggregation of H2WO4, it may effectively act as both dispersant and modifier, leading to further increased WO3 dispersion and weakened W–Al interaction. The catalysts prepared by the microwave hydrothermal method show superior dibenzothiophene hydrodesulfurization activity. This method provides rapidity, convenience and cost effectiveness for preparing active hydrotreating catalysts.

  9. 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

  10. Hydrothermal processes above the Yellowstone magma chamber: Large hydrothermal systems and large hydrothermal explosions

    Science.gov (United States)

    Morgan, L.A.; Shanks, W.C. Pat; Pierce, K.L.

    2009-01-01

    Hydrothermal explosions are violent and dramatic events resulting in the rapid ejection of boiling water, steam, mud, and rock fragments from source craters that range from a few meters up to more than 2 km in diameter; associated breccia can be emplaced as much as 3 to 4 km from the largest craters. Hydrothermal explosions occur where shallow interconnected reservoirs of steam- and liquid-saturated fluids with temperatures at or near the boiling curve underlie thermal fields. Sudden reduction in confi ning pressure causes fluids to fl ash to steam, resulting in signifi cant expansion, rock fragmentation, and debris ejection. In Yellowstone, hydrothermal explosions are a potentially signifi cant hazard for visitors and facilities and can damage or even destroy thermal features. The breccia deposits and associated craters formed from hydrothermal explosions are mapped as mostly Holocene (the Mary Bay deposit is older) units throughout Yellowstone National Park (YNP) and are spatially related to within the 0.64-Ma Yellowstone caldera and along the active Norris-Mammoth tectonic corridor. In Yellowstone, at least 20 large (>100 m in diameter) hydrothermal explosion craters have been identifi ed; the scale of the individual associated events dwarfs similar features in geothermal areas elsewhere in the world. Large hydrothermal explosions in Yellowstone have occurred over the past 16 ka averaging ??1 every 700 yr; similar events are likely in the future. Our studies of large hydrothermal explosion events indicate: (1) none are directly associated with eruptive volcanic or shallow intrusive events; (2) several historical explosions have been triggered by seismic events; (3) lithic clasts and comingled matrix material that form hydrothermal explosion deposits are extensively altered, indicating that explosions occur in areas subjected to intense hydrothermal processes; (4) many lithic clasts contained in explosion breccia deposits preserve evidence of repeated fracturing

  11. A Facile Method for Synthesis of Polygonal Silver Nanopartilces

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The synthesis of nanosized powders and their assembly is of considerable importance to the microelectronics industry because of the pervasive drive to miniaturize components. In this work, silver (Ag) nanoparticls was syntheized. Polygonal silver nanoparticls were synthesized by reacting AgNO3 with hydroquinone, in the presence of poly-(vinylpyrrolidone) (PVP) and an ionic liquid 1-n-butyl-3-methylimidazolium hexafluoroborate ([BMIM]·PF6) at ambient temperature. XRD shows that the crystal structure of the nanoparticles is face-centered cubic. TEM measurements display the silver particles with uniform size and narrow particle size distributions. The UV-Vis spectra of the nanoplates distinguish from those of the samples prepared in the absence of PVP and/or ILs. This method is facile and the as-prepared silver nanoparticls are also stable in some solvents, such as ethanol and water.

  12. Facile Method for Preparation of Silica Coated Monodisperse Superparamagnetic Microspheres

    Directory of Open Access Journals (Sweden)

    Xuan-Hung Pham

    2016-01-01

    Full Text Available This paper presents a facile method for preparation of silica coated monodisperse superparamagnetic microsphere. Herein, monodisperse porous polystyrene-divinylbenzene microbeads were prepared by seeded emulsion polymerization and subsequently sulfonated with acetic acid/H2SO4. The as-prepared sulfonated macroporous beads were magnetized in presence of Fe2+/Fe3+ under alkaline condition and were subjected to silica coating by sol-gel process, providing water compatibility, easily modifiable surface form, and chemical stability. FE-SEM, TEM, FT-IR, and TGA were employed to characterize the silica coated monodisperse magnetic beads (~7.5 μm. The proposed monodisperse magnetic beads can be used as mobile solid phase particles candidate for protein and DNA separation.

  13. Facile colorimetric methods for the quantitative determination of tetramisole hydrochloride

    Science.gov (United States)

    Amin, A. S.; Dessouki, H. A.

    2002-10-01

    A facile, rapid and sensitive methods for the determination of tetramisole hydrochloride in pure and in dosage forms are described. The procedures are based on the formation of coloured products with the chromogenic reagents alizarin blue BB (I), alizarin red S (II), alizarin violet 3R (III) and alizarin yellow G (IV). The coloured products showed absorption maxima at 605, 468, 631 and 388 nm for I-IV, respectively. The colours obtained were stable for 24 h. The colour system obeyed Beer's law in the concentration range 1.0-36, 0.8-32, 1.2-42 and 0.8-30 μg ml -1, respectively. The results obtained showed good recoveries with relative standard deviations of 1.27, 0.96, 1.13 and 1.35%, respectively. The detection and determination limits were found to be 1.0 and 3.8, 1.2 and 4.2, 1.0 and 3.9 and finally 1.4 and 4.8 ng ml -1 for I-IV complexes, respectively. Applications of the method to representative pharmaceutical formulations are represented and the validity assessed by applying the standard addition technique, which is comparable with that obtained using the official method.

  14. Synthesis of nanostructured and microstructured ZnO and Zn(OH)2 on activated carbon cloth by hydrothermal and microwave-assisted chemical bath deposition methods

    Science.gov (United States)

    Mosayebi, Elham; Azizian, Saeid; Hajian, Ali

    2015-05-01

    Nanostructured and microstructured ZnO and Zn(OH)2 loaded on activated carbon cloth were synthesized by microwave-assisted chemical bath deposition and hydrothermal methods. By hydrothermal method the deposited sample on carbon fiber is pure ZnO with dandelion-like nanostructures. By microwave-assisted chemical bath method the structure and composition of deposited sample depends on solution pH. At pH = 9.8 the deposited sample on carbon fiber is pure ZnO with flower-like microstructure; but at pH = 10.8 the sample is a mixture of ZnO and Zn(OH)2 with flower-like and rhombic microstructures, respectively. The mechanism of crystal grow by microwave-assisted chemical bath method was investigated by SEM method at both pH.

  15. 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.

  16. Enhanced Photocatalytic Degradation of Methylene Blue Using ZnFe2O4/MWCNT Composite Synthesized by Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Sonal Singhal

    2013-01-01

    Full Text Available Multiwalled carbon nanotubes (MWCNTs were synthesized using arc discharge method at a magnetic field of 430 G and purified using HNO3/H2O2. Transmission electron micrographs revealed that MWCNTs had inner and outer diameter of ~2 nm and ~4 nm, respectively. Raman spectroscopy confirmed formation of MWCNTs showing G-band at 1577 cm−1. ZnFe2O4 and ZnFe2O4/MWCNT were produced using one step hydrothermal method. Powder X-ray diffraction (XRD confirmed the formation of cubic spinel ZnFe2O4 as well as incorporation of MWCNT into ZnFe2O4. Visible light photocatalytic degradation of methylene blue (MB was studied using pure ZnFe2O4 and ZnFe2O4/MWCNT. The results showed that ZnFe2O4/MWCNT composite had higher photocatalytic activity as compared to pure ZnFe2O4. After irradiation for 5 hours in the visible light, MB was almost 84% degraded in the presence of ZnFe2O4 photocatalyst, while 99% degradation was observed in case of ZnFe2O4/MWCNT composite. This enhancement in the photocatalytic activity of composite may be attributed to the inhibition of recombination of photogenerated charge carriers.

  17. Optical parameters of Al-doped ZnO nanorod array thin films grown via the hydrothermal method.

    Science.gov (United States)

    Kim, Soaram; Kim, Min Su; Nam, Giwoong; Park, Hyunggil; Yoon, Hyunsik; Leem, Jae-Young

    2013-09-01

    ZnO seed layers were deposited onto a quartz substrate using the sol--gel method, and Al-doped ZnO (AZO) nanorod array thin films with different Al concentrations that ranged from 0 to 2.0 at. % were grown on the ZnO seed layers via the hydrothermal method. Optical parameters, including the optical band gap, the absorption coefficient, the Urbach energy, the refractive index, the dispersion parameter, and the optical conductivity, were studied to investigate the effects of Al doping on the optical properties of AZO nanorod array thin films. The optical band gaps of the ZnO and AZO nanorod array thin films were 3.206 at 0 at.%, 3.214 at 0.5 at.%, 3.226 at 1.5 at.%, and 3.268 at 2.0 at.%. The Urbach energy gradually decreased from 126 meV (0 at.%) to 70 meV (2.0 at.%) as the Al concentration was increased. The dispersion energy, the single-oscillator energy, the average oscillator wavelength, the average oscillator strength, the refractive index, and the optical conductivity of the AZO nanorod array thin films were all affected by Al doping.

  18. Mapping deep-sea hydrothermal deposits with an in-loop transient electromagnetic method: Insights from 1D forward and inverse modeling

    Science.gov (United States)

    Jang, Hangilro; Kim, Hee Joon

    2015-12-01

    In transient electromagnetic (TEM) measurements, secondary fields that contain information on conductive targets such as hydrothermal mineral deposits in the seafloor can be measured in the absence of strong primary fields. A TEM system using a loop source is useful to the development of compact, autonomous instruments, which are well suited to submersible-based surveys. In this paper, we investigate the possibility of applying an in-loop TEM system to the detection of marine hydrothermal deposits through a one-dimensional modeling and inversion study. We examine step-off responses for a layered model and compare the characteristics of horizontal and vertical loop systems for detecting hydrothermal deposits. The feasibility study shows that TEM responses are very sensitive to a highly conductive layer. Time-domain target responses are larger and appear earlier in horizontal magnetic fields than in vertical ones, although the vertical field has 2-3 times larger magnitude than the horizontal one. An inverse problem is formulated with the Gauss-Newton method and solved with the damped and smoothness-constrained least-squares approach. The test example for a marine hydrothermal TEM survey demonstrated that the depth extent, conductivity and thickness of the highly conductive layer are well resolved.

  19. Structural and optical study of CaF2 nanoparticles produced by a microwave-assisted hydrothermal method

    Science.gov (United States)

    Bezerra, Claudiane dos S.; Valerio, Mário E. G.

    2016-11-01

    CaF2 nanoparticles were synthesized by the microwave-assisted hydrothermal method. With the addition of the ethylenediamine (EDA) as chelating agent, the size of the particles was reduced. The CaF2 exhibit single phase identified for X-ray diffraction (XRD) and confirmed by Rietveld refinement. Scanning electron microscopy (SEM) images showed nanoparticles with non-uniform morphology and statistical analysis of collections of particles reviewed that the EDA decreases both the average particle size and average aspect ratio of the particles. The chemical composition of the surface of the particles was investigated by X-ray Photoelectron Spectroscopy (XPS) and the results indicated the presence of reasonable amounts of hydroxyl groups and oxygen ions in the samples produced with EDA. Radioluminescence (RL) measurements showed that both types of nanoparticles presented intrinsic scintillation emission formed by two main bands and that the CaF2 samples produced without EDA presented higher emission intensity. The broad RL band centered at approximately 293 nm is related to self-trapped exciton (STE) emission of calcium fluoride, while the band at 428 nm can be due to the presence of F centers. The STE excitation and optical band gap were measured through photoluminescent excitation spectra in the VUV range.

  20. Adsorption and photocatalytic degradation of methylene blue using high surface area titanate nanotubes (TNT) synthesized via hydrothermal method

    Science.gov (United States)

    Subramaniam, M. N.; Goh, P. S.; Abdullah, N.; Lau, W. J.; Ng, B. C.; Ismail, A. F.

    2017-06-01

    Removal of methylene blue (MB) via adsorption and photocatalysis using titanate nanotubes (TNTs) with different surface areas were investigated and compared to commercial titanium dioxide (TiO2) P25 Degussa nanoparticles. The TNTs with surface area ranging from 20 m2/g to 200 m2/g were synthesized via hydrothermal method with different reaction times. TEM imaging confirmed the tubular structure of TNT while XRD spectra indicated all TNTs exhibited anatase crystallinity. Batch adsorption rate showed linearity with surface properties of TNTs, where materials with higher surface area showed higher adsorption rate. The highest MB adsorption (70%) was achieved by TNT24 in 60 min whereas commercial TiO2 exhibited the lowest adsorption of only 10% after 240 min. Adsorption isotherm studies indicated that adsorption using TNT is better fitted into Langmuir adsorption isotherm than Freundlich isotherm model. Furthermore, TNT24 was able to perform up to 90% removal of MB within 120 min, demonstrating performance that is 2-fold better compared to commercial TiO2. The high surface area and surface Bronsted acidity are the main reasons for the improvement in MB removal performance exhibited by TNT24. The improvement in surface acidity enhanced the adsorption properties of all the nanotubes prepared in this study.

  1. Structural and room temperature ferromagnetic properties of Ni doped ZnO nanoparticles via low-temperature hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Kun; Liu, Changzhen, E-mail: liuchangzhen94@163.com; Chen, Rui; Fang, Xiaoxiang; Wu, Xiuling; Liu, Jie

    2016-12-01

    A series of Zn{sub 1−x}Ni{sub x}O (x=0, 1%, 3%, 5%) nanoparticles have been synthesized via a low-temperature hydrothermal method. Influence of Ni doping concentration on the structure, morphology, optical properties and magnetism of the samples was investigated by means of X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, UV–vis spectrophotometer and vibrating sample magnetometer instruments. The results show that the undoped and doped ZnO nanoparticles are both hexagonal wurtzite structures. The surface analysis was performed using X-ray photoelectron spectroscopic studies. The images of SEM reveal that the structure of pure ZnO and Ni doped samples are nanoparticles which intended to form flakes with thickness of few nanometers, being overlain with each one to develop the network with some pores and voids. Based on the ultraviolet–visible (UV–vis) spectroscopy analysis, it indicates that the band gap energy decreases with the increasing concentration of Ni. Furthermore, The Ni doped ZnO samples didn't exhibit higher ultraviolet-light-driven photocatalytic activity compared to the undoped ZnO sample. Vibrating sample magnetometer was used for the magnetic property investigations, and the result indicates that room temperature ferromagnetism property of 3% Ni doped sample is attributed to oxygen vacancy and interaction between doped ions.

  2. Structural and room temperature ferromagnetic properties of Ni doped ZnO nanoparticles via low-temperature hydrothermal method

    Science.gov (United States)

    Xu, Kun; Liu, Changzhen; Chen, Rui; Fang, Xiaoxiang; Wu, Xiuling; Liu, Jie

    2016-12-01

    A series of Zn1-xNixO (x=0, 1%, 3%, 5%) nanoparticles have been synthesized via a low-temperature hydrothermal method. Influence of Ni doping concentration on the structure, morphology, optical properties and magnetism of the samples was investigated by means of X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, UV-vis spectrophotometer and vibrating sample magnetometer instruments. The results show that the undoped and doped ZnO nanoparticles are both hexagonal wurtzite structures. The surface analysis was performed using X-ray photoelectron spectroscopic studies. The images of SEM reveal that the structure of pure ZnO and Ni doped samples are nanoparticles which intended to form flakes with thickness of few nanometers, being overlain with each one to develop the network with some pores and voids. Based on the ultraviolet-visible (UV-vis) spectroscopy analysis, it indicates that the band gap energy decreases with the increasing concentration of Ni. Furthermore, The Ni doped ZnO samples didn't exhibit higher ultraviolet-light-driven photocatalytic activity compared to the undoped ZnO sample. Vibrating sample magnetometer was used for the magnetic property investigations, and the result indicates that room temperature ferromagnetism property of 3% Ni doped sample is attributed to oxygen vacancy and interaction between doped ions.

  3. Synthesis and characterization of PbTe micro/nanostructures through hydrothermal method by using a novel capping agent

    Indian Academy of Sciences (India)

    Shahla Ahmadian-Fard-Fini; Masoud Salavati-Niasari; Fatemeh Mohandes

    2014-06-01

    For the first time, a Schiff base compound derived from 1,8-diamino-3,6-dioxaoctane and 2-hydroxybenzophenone marked as (2-HBP)-(DaDo) was synthesized, characterized and then used as capping agent for the preparation of PbTe micro/nanostructures. Besides the as-synthesized Schiff base compound, Pb(NO3)2 and Te powders were applied as lead and telluride precursors. In addition, effect of preparation parameters like reaction time and temperature in hydrothermal synthesis on the morphology of the final products was tested. The products were analysed with the aid of SEM, XRD, FT–IR and EDS. Based on the obtained results, it was found that pure cubic phased PbTe has been obtained by this method. According to SEM images, it was found that uniform PbTe micro/nanocubes have been obtained at 180°C for 12 h. On the other hand, by increasing the reaction temperature from 3 to 24 h, the production of cubic-like shapes increased.

  4. Self-Etching-Induced Morphological Evolution of ZnO Microrods Grown on FTO Glass by Hydrothermal Method

    Science.gov (United States)

    Hsu, Wen-Dung; Tsai, Jenn-Kai; Meen, Teen-Hang; Wu, Tian-Chiuan; He, Yan-Kuan; Lai, Yu-Da

    2015-10-01

    In this research, the zinc oxide (ZnO) microrods were grown by hydrothermal method on fluorine-doped tin oxide (FTO) glass functionalized by self-assembled monolayer of octadecyltrimethoxysilane (ODS; CH3(CH2)17Si(OCH3)3). The sharp-tip or polygonal shape with specific facets at the top end of ZnO microrods can be obtained by post retention at low temperature. The morphologies were characterized by the field-emission scanning electron microscope (FESEM) and transmission electron microscopy (TEM). The results confirm that the morphology change at the top end is due to self-etching. The mechanism responsible for the formation of various top-end morphologies was proposed. The specific facets that left after 6-h retention were identified. The room-temperature micro-photoluminescence spectra showed a strong ultraviolet emission at 387 nm, and a broad emission at a range of from 500 to 700 nm. The morphology change also influences the photoluminescence (PL) spectra. A satellite peak in the UV emission spectra was observed. The peak may be attributed to the morphology effect of the microrods.

  5. Degradation of Rhodamine B Dye by TiO2 Nanotubes Photocatalyst Synthesized via Alkaline Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    T Mazlina Mat Darus

    2015-01-01

    Full Text Available Titanium dioxide (TiO2 nanotubes have successfully been synthesized by using one step approach of hydrothermal method. Commercial TiO2 (anatase powder was used as precursor to synthesize the TiO2 nanotubes. The TiO2 nanotubes were synthesized at 120 °C/20 hrs in an alkaline solution of NaOH. The photocatalytic study of the as-synthesized samples was conducted by analyzing the degradation of Rhodamine B (Rh B dye under UV light irradiation. Rh B is a toxic dye which is commonly used in textile industry. It is the one of the most common pollutants in the effluents and highly soluble in water. A comparison study was carried out in order to investigate the photocatalytic activity between the synthesized TiO2 nanotubes and the commercial TiO2 nanoparticles. Results show that the TiO2 nanotubes exhibits better photocatalytic activity in the degradation of Rh B as compared to the TiO2 nanoparticles.

  6. Adsorption of Pb(II) and Cd(II) from aqueous solutions using titanate nanotubes prepared via hydrothermal method.

    Science.gov (United States)

    Xiong, Lin; Chen, Cheng; Chen, Qing; Ni, Jinren

    2011-05-30

    Titanate nanotubes (TNs) with specific surface areas of 272.31 m(2)g(-1) and pore volumes of 1.264 cm(3)g(-1) were synthesized by alkaline hydrothermal method. The TNs were investigated as adsorbents for the removal of Pb(II) and Cd(II) from aqueous solutions. The FT-IR analysis indicated that Pb(II) and Cd(II) adsorption were mainly ascribed to the hydroxyl groups in the TNs. Batch experiments were conducted by varying contact time, pH and adsorbent dosage. It was shown that the initial uptake of each metal ion was very fast in the first 5 min, and adsorption equilibrium was reached after 180 min. The adsorption of Pb(II) and Cd(II) were found to be maximum at pH in the range of 5.0-6.0. The adsorption kinetics of both metal ions followed the pseudo-second-order model. Equilibrium data were best fitted with the Langmuir isotherm model, and the maximum adsorption capacities of Pb(II) and Cd(II) were determined to be 520.83 and 238.61 mg g(-1), respectively. Moreover, more than 80% of Pb(II) and 85% of Cd(II) adsorbed onto TNs can be desorbed with 0.1M HCl after 3h. Thus, TNs were considered to be effective and promising materials for the removal of both Pb(II) and Cd(II) from wastewater.

  7. MnO2 prepared by hydrothermal method and electrochemical performance as anode for lithium-ion battery.

    Science.gov (United States)

    Feng, Lili; Xuan, Zhewen; Zhao, Hongbo; Bai, Yang; Guo, Junming; Su, Chang-Wei; Chen, Xiaokai

    2014-01-01

    Two α-MnO2 crystals with caddice-clew-like and urchin-like morphologies are prepared by the hydrothermal method, and their structure and electrochemical performance are characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), galvanostatic cell cycling, cyclic voltammetry, and electrochemical impedance spectroscopy (EIS). The morphology of the MnO2 prepared under acidic condition is urchin-like, while the one prepared under neutral condition is caddice-clew-like. The identical crystalline phase of MnO2 crystals is essential to evaluate the relationship between electrochemical performances and morphologies for lithium-ion battery application. In this study, urchin-like α-MnO2 crystals with compact structure have better electrochemical performance due to the higher specific capacity and lower impedance. We find that the relationship between electrochemical performance and morphology is different when MnO2 material used as electrochemical supercapacitor or as anode of lithium-ion battery. For lithium-ion battery application, urchin-like MnO2 material has better electrochemical performance.

  8. MnO2 prepared by hydrothermal method and electrochemical performance as anode for lithium-ion battery

    Science.gov (United States)

    2014-01-01

    Two α-MnO2 crystals with caddice-clew-like and urchin-like morphologies are prepared by the hydrothermal method, and their structure and electrochemical performance are characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), galvanostatic cell cycling, cyclic voltammetry, and electrochemical impedance spectroscopy (EIS). The morphology of the MnO2 prepared under acidic condition is urchin-like, while the one prepared under neutral condition is caddice-clew-like. The identical crystalline phase of MnO2 crystals is essential to evaluate the relationship between electrochemical performances and morphologies for lithium-ion battery application. In this study, urchin-like α-MnO2 crystals with compact structure have better electrochemical performance due to the higher specific capacity and lower impedance. We find that the relationship between electrochemical performance and morphology is different when MnO2 material used as electrochemical supercapacitor or as anode of lithium-ion battery. For lithium-ion battery application, urchin-like MnO2 material has better electrochemical performance. PMID:24982603

  9. Synthesis of TiO2 nanorods from titania and titanyl sulfate produced from ilmenite dissolution by hydrothermal method

    Science.gov (United States)

    Wahyuningsih, S.; Ramelan, A. H.; Munifa, R. M. I.; Saputri, L. N. M. Z.; Chasanah, U.

    2016-11-01

    TiO2 powder has been synthesized through hydrolysis-condensation of titanyl sulfate solution to a starting material of TiO2 nanorods formation. This processing was conducted by the solid separation of TiO2 from ilmenite by roasting ilmenite, acidic leaching (hydrolysis), and co-precipitation (condensation). Roasting of ilmenite was carried out by the addition of Na2S at a temperature of 800°C. While the acidic leaching process was conducted by sulfuric acid at a various concentrations of 3, 3.5, 4.5, 6, and 9 M. The result shown that the solubility optimum occurs in H2SO4 6 M condition. Separation of Fe impurities of TiO2 gel from titanyl sulfate (TiOSO4) solution was done through complexation using KCNS addition. The characteristic of TiO2 obtained using X-Ray Fluorescence (XRF) and X-Ray Diffraction (XRD) showed good crystallinity and purity. Further treatment of the TiO2 is the formation of one-dimensional nano-size (1-D nanorods) through a hydrothermal method under basic condition NaOH 12M solution. TiO2 nanorods were confirmed by Transmission Electron Microscope (TEM) which indicated that the diameter of TiO2 nanorods was about 7.02 nm in size.

  10. Synthesis of Sub-micrometer Lithium Iron Phosphate Particles for Lithium Ion Battery by Using Supercritical Hydrothermal Method

    Institute of Scientific and Technical Information of China (English)

    张艳洁; 杨艳芳; 王学勇; 李帅三

    2014-01-01

    A supercritical hydrothermal method was employed to prepare sub-micrometer LiFePO4 particles with high purity and crystallinity. The structure and morphology of LiFePO4 particles were characterized by X-ray dif-fraction and scanning electron microscope. The electrochemical tests were carried out to determine the reversible capacity, rate and cycling performance of the LiFePO4 particles as cathode material for lithium ion battery. Experi-mental results show that solvent and calcining time have significant effects on purity, size and morphology of LiFePO4 particles. Mixed solvent contained deionized water and ethanol is conducive to synthesize smaller and more uniform particles. The size of LiFePO4 particles as-prepared is about 100-300 nm. The specific discharge ca-pacities of the LiFePO4 particles are 151.3 and 128.0 mA·h·g-1 after first cycle at the rates of 0.1 and 1.0 C, respec-tively. It retains 95.0%of the initial capacity after 100 cycles at 1.0 C.

  11. Preparation and characterization of PVA–I complex doped mesoporous TiO{sub 2} by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Qian [School of Chemistry and Material Science, Nanjing Normal University, Nanjing 210097 (China); Jiang, Caiyun [Department of Engineering and Technology, Jiangsu Institute of Economic and Trade Technology, Nanjing 210007 (China); Wang, Yuping, E-mail: wangyuping@njnu.edu.cn [School of Chemistry and Material Science, Nanjing Normal University, Nanjing 210097 (China); Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, Nanjing University of Science and Technology, 210093 (China); Yang, Weiben; Yang, Chun [School of Chemistry and Material Science, Nanjing Normal University, Nanjing 210097 (China)

    2013-05-15

    Polyvinyl alcohol [PVA]–iodine complex doped mesoporous TiO{sub 2} (PIT) and iodine doped (IT) catalysts were prepared by hydrothermal method, using tetrabutyl titanate as precursor, potassium iodate and iodine as iodine sources. The as-prepared PIT and IT catalysts were characterized by UV–vis, XRD, FESEM, BET, TG/DTA, XPS and photoluminescence (PL) spectroscopy. Production of ·OH radicals on the surface of photocatalyst was detected by the PL technique using terephthalic acid as a probe molecule. The influences of calcinated temperature on the structure and properties of the catalysts were investigated. The photocatalytic activity of catalysts was evaluated through photocatalytic decolorization of methylene blue (MB) aqueous solution. The results showed that PIT samples were anatase mesoporous TiO{sub 2} and their iodine content and mesoporous structure were influenced by calcinated temperature. Particle size of PIT samples was smaller than that of IT as a result of the PVA skeleton and regular structure. Because of the complexation of iodine and PVA, thermostability of iodine is improved and the amount of iodine in PIT calcinated at 200 °C (PIT-200) is higher than that of IT calcinated at same temperature. Light absorption range and intensity of PIT-200 has been greatly improved due to the synergy of iodine and carbon. The efficiency of photocatalysis for MB is greatly improved with TiO{sub 2} modified by PVA–I complex under simulated sun light irradiation.

  12. Facile preparation method for rare earth phosphate hollow spheres and their photoluminescence properties.

    Science.gov (United States)

    Guan, Mingyun; Tao, Feifei; Sun, Jianhua; Xu, Zheng

    2008-08-01

    We have developed a template-free hydrothermal method of constructing rare earth phosphate hollow spheres using H(6)P(4)O(13) as the PO(4) (3-) source. The mechanism of hollow spheres formation was proposed on the basis of Ostwald ripening. The resulting hollow spheres, especially with the aid of doping of other lanthanide cations, exhibit emission spanning the whole UV-visible wavelength range.

  13. Fast preparation of LiFePO4 nanoparticles for lithium batteries by microwave-assisted hydrothermal method.

    Science.gov (United States)

    Yang, Gang; Ji, Hongmei; Liu, Haidong; Huo, Kaifu; Fu, Jijiang; Chu, Paul K

    2010-02-01

    Nanomaterial for lithium batteries can decrease mechanical strain upon lithium intercalation/ deintercalation from lattice, and lead to high rate capability. The currently available microwave technology permits the development and implantation of a temperature-controlled microwave-assisted hydrothermal synthesis (TCMH) of nano-sized cathode material for lithium batteries. Unlike in previous reported traditional hydrothermal synthesis of cathode material LiFePO4, the pure phase of LiFePO4 can be simply and rapidly synthesized for 5 minutes in water under hydrothermal treatment with microwave irradiation. The homogeneous effects induced by microwave irradiation could create a uniform seeding condition. The colloid precursor Li3PO4 plays the key role to be the nucleation center for the new phase while the formation energy for LiFePO4 would be decreased during the following microwave irradiation. The as-prepared pristine LiFePO4 without carbon coating are characterized by X-ray diffraction, Raman, scanning and transmission electron microscopy, and tested as the cathode in lithium batteries. The particle sizes of pristine LiFePO4 are dependent on hydrothermal and microwave-assisted hydrothermal condition and the electrochemical performance are relatively determined.

  14. Photocatalytic properties of h-WO3 nanoparticles obtained by annealing and h-WO3 nanorods prepared by hydrothermal method

    Science.gov (United States)

    Boyadjiev, Stefan I.; Nagy-Kovács, Teodóra; Lukács, István; Szilágyi, Imre M.

    2016-03-01

    In the present study, two different methods for preparing hexagonal WO3 (h-WO3) photocatalysts were used - controlled thermal decomposition and hydrothermal synthesis. WO3 nanoparticles with hexagonal structure were obtained by annealing (NH4)xWO3-y at 500 °C in air. WO3 nanorods were prepared by a hydrothermal method using sodium tungstate Na2WO4, HCl, (COOH)2 and NaSO4 precursors at 200 °C. The formation, morphology, structure and composition of the as-prepared nanoparticles and nanorods were studied by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy combined with energy-dispersive X-ray spectroscopy (SEM-EDX). The photocatalytic activity of the h-WO3 nanoparticles and nanorods was studied by decomposing methyl orange in aqueous solution under UV light irradiation.

  15. Upconversion Luminescence Properties of Ho3+, Tm3+, Yb3+ Co-Doped Nanocrystal NaYF4 Synthesized by Hydrothermal Method

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Nanocrystal of upconversion (UC) phosphor Ho3+, Tm3+, and Yb3+ co-doped NaYF4 was prepared by the hydrothermal method in the presence of the complexing agent EDTA. Under 980 nm diode laser excitation, the impact of different concentrations of Ho3+ ion on the UC luminescence intensity was discussed. The law of luminescence intensity versus pump power shows that the 474 nm blue emission, 538 nm green emission, and 642 nm red emission are all due to the two-photon process, while the 450 nm blue emission is a three-photon process. The UC mechanism and processes were also analyzed. The sample was characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The result shows that Ho3+, Tm3+, and Yb3+ co-doped NaYF4 prepared by the hydrothermal method exhibits a hexagonal nanocrystal.

  16. Characterisation of ZnO nanorod arrays grown by a low temperature hydrothermal method

    Science.gov (United States)

    Kahraman, S.; Çetinkara, H. A.; Bayansal, F.; Çakmak, H. M.; Güder, H. S.

    2012-06-01

    In this paper, growth steps of well defined ZnO nanorod arrays deposited on seeded substrates were investigated. To obtain ZnO seed layer on glass substrates, a successive ionic layer adsorption and reaction (SILAR) method was used and then ZnO nanorods were grown on seed layer using a chemical bath deposition (CBD) method. The effects of seed layer and deposition time on morphology, crystallographic structure (e.g. grain size, microstrain and dislocation density) and electrical characteristics of ZnO nanorods were studied. From the SEM micrographs, it could be seen that the ZnO nanorods densely covered the substrate and were nearly perpendicular to the substrate surface. The XRD patterns showed that the ZnO nanorod arrays had a hexagonal wurtzite structure with a preferred orientation along the (002) plane. An increase in deposition time resulted in an increase in the intensity of the preferred orientation and grain size, but a decrease in microstrain and dislocation density. Electrical activation energies of the structures were calculated as 0.15-0.85 eV from current-temperature characteristics. It was concluded that the morphologies of the structures obtained in this study via a simple and fast solution method can provide high surface areas which are important in area-dependent applications, such as solar cells, hydrogen conversion devices, sensors, etc.

  17. Electromagnetic properties of nanocrystalline Al$^{3+}$ substituted MgCuMn ferrites synthesized by microwave hydrothermal method

    Indian Academy of Sciences (India)

    T RAMESH; S R MURTHY

    2016-10-01

    The effect of Al$^{3+}$ substitution on electromagnetic properties has been studied for nanocrystalline Mg$_{0.8}$Cu$_{0.2}Mn$_{0.05}$Al$_x$Fe$_{1.95−x}$O$_4$ ferrites, wherein $x$ varies from 0 to 0.4 in steps of 0.1. These ferrites were synthesizedby using microwave hydrothermal method and then characterized using X-ray diffractometer (XRD), Fourier transform infrared and transmission electron microscopy. The synthesized powders were densified using microwavesintering method at 950◦C/50 min. Structural and surface morphology of sintered samples were characterized using XRD and atomic force microscopy, respectively. The complex permittivity and permeability properties were measuredover a frequency range 100 Hz–1.8 GHz. The temperature variation of magnetic properties were measured in the temperature range of 300–650 K. The electrical and magnetization studies inferred that the values of d.c. resistivity increases by 27%, whereas saturation magnetization decreases linearly from 38.6 to 23.0 emu g$^{−1}$ and Curie temperature was found to be decreased from 628 to 513 K with an increase of Al$^{3+}$ ions. The low dielectric, magnetic losses, moderate saturation magnetization and high-temperature stability properties exhibited by Al$^{3+}$ substituted MgCuMn ferrites make them find applications in microwave devices, such as circulators and isolators etc. The applicability of present samples formicrowave devices has been tested by the measurement of ferromagnetic resonance linewidth at K$_a$ band.

  18. Photocatalytic properties of titanate nanotube powders prepared by alkaline hydrothermal method.

    Science.gov (United States)

    Lee, Heon; Park, Sung Hoon; Kim, Sun-Jae; Kim, Byung Hoon; Chung, Minchul; Ahn, Ho-Geun; Kim, Sang-Chai; Jung, Sang-Chul

    2011-08-01

    This paper reports the photocatalytic activities of titanate nanotubes (TNTs) synthesized using different methods and compares them with that of P25. Rhodamine B was selected as the organic compound to be decomposed by the microwave/UV/photocatalyst hybrid process. The as-prepared TNT had titanate crystalline structure, whereas the TNT calcined at 723 K was phase-transformed into anatase structure. When the as-prepared TNT was ion-exchanged using HCl, Na+ content was reduced from 8.36 wt% to 0.03 wt%. The ion-exchanged TNT showed the highest photocatalytic activity among the TNTs tested in this study, but it was lower than that of P25.

  19. Mimicking natural fibrous structures of opals by means of a microemulsion-mediated hydrothermal method.

    Science.gov (United States)

    Hassan, Natalia; Verdinelli, Valeria; Ruso, Juan M; Messina, Paula V

    2011-07-19

    Silica-based nanomaterials are of great interest because of their potential applications in constructing electronic and optoelectronic nanodevices. Especially significant are those that combine the properties of photonic crystal with a fibrous semiconductor structure. Here we report the use of microemulsion droplet systems as a simple and controllable route for the synthesis of 3D opals materials with an unusual fibrous microstructure similar to those that exist in nature. By this method, we demonstrate the creation of very long fibrils of 30-50 nm diameter and more than 20 μm length showing simultaneous short and long wavelength light emissions and band gap values (5.50 and 4.41 eV) comparable to those obtained for silicon-based metal oxide semiconductors.

  20. Hydrothermal minerals

    Digital Repository Service at National Institute of Oceanography (India)

    Nath, B.N.

    -floor hydrothermal processes involving free circulation of seawater through ocean crust as convection. Heat flow, seafloor fracturing, permeability and fluid composition are the parameters governing the type and extent of mineralization. The chimney like... stream_size 23365 stream_content_type text/plain stream_name Refresher_Course_Mar_Geol_Geophys_2007_Lecture_Notes_78.pdf.txt stream_source_info Refresher_Course_Mar_Geol_Geophys_2007_Lecture_Notes_78.pdf.txt Content-Encoding UTF-8...

  1. Hydrothermal liquefaction of biomass

    DEFF Research Database (Denmark)

    Toor, Saqib; Rosendahl, Lasse; Hoffmann, Jessica

    2014-01-01

    Biomass is one of the most abundant sources of renewable energy, and will be an important part of a more sustainable future energy system. In addition to direct combustion, there is growing attention on conversion of biomass into liquid en-ergy carriers. These conversion methods are divided...... into liquid biofuels, with the aim of describing the current status and development challenges of the technology. During the hydrothermal liquefaction process, the biomass macromolecules are first hydrolyzed and/or degraded into smaller molecules. Many of the produced molecules are unstable and reactive...... into biochemical/biotechnical methods and thermochemical methods; such as direct combustion, pyrolysis, gasification, liquefaction etc. This chapter will focus on hydrothermal liquefaction, where high pressures and intermediate temperatures together with the presence of water are used to convert biomass...

  2. Hydrothermal liquefaction of biomass

    DEFF Research Database (Denmark)

    Toor, Saqib; Rosendahl, Lasse; Hoffmann, Jessica

    2014-01-01

    Biomass is one of the most abundant sources of renewable energy, and will be an important part of a more sustainable future energy system. In addition to direct combustion, there is growing attention on conversion of biomass into liquid en-ergy carriers. These conversion methods are divided...... into biochemical/biotechnical methods and thermochemical methods; such as direct combustion, pyrolysis, gasification, liquefaction etc. This chapter will focus on hydrothermal liquefaction, where high pressures and intermediate temperatures together with the presence of water are used to convert biomass...... into liquid biofuels, with the aim of describing the current status and development challenges of the technology. During the hydrothermal liquefaction process, the biomass macromolecules are first hydrolyzed and/or degraded into smaller molecules. Many of the produced molecules are unstable and reactive...

  3. Modelling of Thermal Advective Reactive Flow in Hydrothermal Mineral Systems Using an Implicit Time-stepped Finite Element Method.

    Science.gov (United States)

    Hornby, P. G.

    2005-12-01

    Understanding chemical and thermal processes taking place in hydrothermal mineral deposition systems could well be a key to unlocking new mineral reserves through improved targeting of exploration efforts. To aid in this understanding it is very helpful to be able to model such processes with sufficient fidelity to test process hypotheses. To gain understanding, it is often sufficient to obtain semi-quantitative results that model the broad aspects of the complex set of thermal and chemical effects taking place in hydrothermal systems. For example, it is often sufficient to gain an understanding of where thermal, geometric and chemical factors converge to precipitate gold (say) without being perfectly precise about how much gold is precipitated. The traditional approach is to use incompressible Darcy flow together with the Boussinesq approximation. From the flow field, the heat equation is used to advect-conduct the heat. The flow field is also used to transport solutes by solving an advection-dispersion-diffusion equation. The reactions in the fluid and between fluid and rock act as source terms for these advection-dispersion equations. Many existing modelling systems that are used for simulating such systems use explicit time marching schemes and finite differences. The disadvantage of this approach is the need to work on rectilinear grids and the number of time steps required by the Courant condition in the solute transport step. The second factor can be particularly significant if the chemical system is complex, requiring (at a minimum) an equilibrium calculation at each grid point at each time step. In the approach we describe, we use finite elements rather than finite differences, and the pressure, heat and advection-dispersion equations are solved implicitly. The general idea is to put unconditional numerical stability of the time integration first, and let accuracy assume a secondary role. It is in this sense that the method is semi-quantiative. However

  4. Rapid Hydrothermal Synthesis of Zinc Oxide Nanowires by Annealing Methods on Seed Layers

    Directory of Open Access Journals (Sweden)

    Jang Bo Shim

    2011-01-01

    Full Text Available Well-aligned zinc oxide (ZnO nanowire arrays were successfully synthesized on a glass substrate using the rapid microwave heating process. The ZnO seed layers were produced by spinning the precursor solutions onto the substrate. Among coatings, the ZnO seed layers were annealed at 100°C for 5 minutes to ensure particle adhesion to the glass surface in air, nitrogen, and vacuum atmospheres. The annealing treatment of the ZnO seed layer was most important for achieving the high quality of ZnO nanowire arrays as ZnO seed nanoparticles of larger than 30 nm in diameter evolve into ZnO nanowire arrays. Transmission electron microscopy analysis revealed a single-crystalline lattice of the ZnO nanowires. Because of their low power (140 W, low operating temperatures (90°C, easy fabrication (variable microwave sintering system, and low cost (90% cost reduction compared with gas condensation methods, high quality ZnO nanowires created with the rapid microwave heating process show great promise for use in flexible solar cells and flexible display devices.

  5. Liquid Glass: A Facile Soft Replication Method for Structuring Glass.

    Science.gov (United States)

    Kotz, Frederik; Plewa, Klaus; Bauer, Werner; Schneider, Norbert; Keller, Nico; Nargang, Tobias; Helmer, Dorothea; Sachsenheimer, Kai; Schäfer, Michael; Worgull, Matthias; Greiner, Christian; Richter, Christiane; Rapp, Bastian E

    2016-06-01

    Liquid glass is a photocurable amorphous silica nanocomposite that can be structured using soft replication molds and turned into glass via thermal debinding and sintering. Simple polymer bonding techniques allow the fabrication of complex microsystems in glass like microfluidic chips. Liquid glass is a step toward prototyping of glass microstructures at low cost without requiring cleanroom facilities or hazardous chemicals.

  6. Linear facility location in three dimensions - Models and solution methods

    DEFF Research Database (Denmark)

    Brimberg, Jack; Juel, Henrik; Schöbel, Anita

    2002-01-01

    We consider the problem of locating a line or a line segment in three-dimensional space, such that the sum of distances from the facility represented by the line (segment) to a given set of points is minimized. An example is planning the drilling of a mine shaft, with access to ore deposits through...

  7. Linear facility location in three dimensions - Models and solution methods

    DEFF Research Database (Denmark)

    Brimberg, Jack; Juel, Henrik; Schöbel, Anita

    2002-01-01

    We consider the problem of locating a line or a line segment in three-dimensional space, such that the sum of distances from the facility represented by the line (segment) to a given set of points is minimized. An example is planning the drilling of a mine shaft, with access to ore deposits through...

  8. Effect of ammonia on morphology, wettability and photoresponse of ZnO nanorods grown by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Jianguo; Yan, Pengpeng [School of Electronic and Information Engineering, Hefei Normal University, Hefei 230601 (China); Zhao, Min, E-mail: zhaomin@hftc.edu.cn [School of Electronic and Information Engineering, Hefei Normal University, Hefei 230601 (China); Sun, Yue; Shang, Fengjiao [School of Electronic and Information Engineering, Hefei Normal University, Hefei 230601 (China); He, Gang, E-mail: hegang@ahu.edu.cn [School of Physics and Material Science, Anhui University, Hefei 230039 (China); Zhang, Miao [School of Physics and Material Science, Anhui University, Hefei 230039 (China); Sun, Zhaoqi, E-mail: szq@ahu.edu.cn [School of Physics and Material Science, Anhui University, Hefei 230039 (China)

    2015-11-05

    ZnO nanorods were prepared on glass at the temperature of 95° using a hydrothermal method. Microstructure, surface morphology, optical properties, wettability and UV photoreponse of the ZnO nanorods were measured by X-ray diffractometry, scanning electron microscopy, UV–vis spectrophotometer, laser micro-Raman spectrometer, home-made water contact angle apparatus and interactive source meter instrument. The results indicate that the ZnO nanorods appear hexagonal wurtzite structure with a preferred orientation along c-axis. The surface morphology changes from flat hexagonal crystallographic plane to tapered tip, which may be attributed to a dynamic equilibrium between ZnO formation and dissolution. Shift of the absorption edge could be attributed to synergy of the surface morphology and Burstein-Moss effect. The intensity ratio of the visible emission to the UV emission decreases with increasing ammonia additive. Enhanced hydrophobicity and the light-induced reversible wettability of the samples could be attributed to the decrease of surface area fraction of solid and interspaces between ZnO nanorods. The sample with ammonia additive of 2.4 mL has the faster photoresponse, which could be attributed to decrease of the structural point defects. - Highlights: • ZnO nanorods have hexagonal structure with a preferential c-axis orientation. • Shape of ZnO nanorods changes from flat planes to tapered tip. • Wettability could be reversibly switched from hydrophobicity to hydrophilicity. • The faster photoresponse could be attributed to the decrease of point defects.

  9. Rapid synthesis of Ti-MCM-41 by microwave-assisted hydrothermal method towards photocatalytic degradation of oxytetracycline.

    Science.gov (United States)

    Chen, Hanlin; Peng, Yen-Ping; Chen, Ku-Fan; Lai, Chia-Hsiang; Lin, Yung-Chang

    2016-06-01

    This study employed microwave-assisted hydrothermal method to synthesize Ti-MCM-41, which are mesoporous materials with a high surface area and excellent photocatalytic ability. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and ultraviolet-visible spectroscopy (UV-Vis) were employed. The XRD findings showed that Ti-MCM-41 exhibited a peak at 2θ of 2.2°, which was attributed to the hexagonal MCM-41 structure. The BET (Brunauer-Emmett-Teller) results agreed with the TEM findings that Ti-MCM-41 has a pore size of about 3-5nm and a high surface area of 883m(2)/g. FTIR results illustrated the existence of Si-O-Si and Si-O-Ti bonds in Ti-MCM-41. The appearance of Ti 2p peaks in the XPS results confirmed the FTIR findings that the Ti was successfully doped into the MCM-41 structure. Zeta (ζ)-potential results indicated that the iso-electric point (IEP) of Ti-MCM-41 was at about pH3.02. In this study, the photocatalytic degradation of oxytetracycline (OTC) at different pH was investigated under Hg lamp irradiation (wavelength 365nm). The rate constant (K'obs) for OTC degradation was 0.012min(-1) at pH3. Furthermore, TOC (total organic carbon) and high resolution LC-MS (liquid chromatography-mass spectrometry) analyses were conducted to elucidate the possible intermediate products and degradation pathway for OTC. The TOC removal efficiency of OTC degradation was 87.0%, 74.4% and 50.9% at pH3, 7 and 10, respectively. LC-MS analysis results showed that the degradation products from OTC resulted from the removal of functional groups from the OTC ring.

  10. Characterization and magnetic properties of SrTi1-xNixO3 nanoparticles prepared by hydrothermal method

    Science.gov (United States)

    Karaphun, Attaphol; Hunpratub, Sitchai; Phokha, Sumalin; Putjuso, Thanin; Swatsitang, Ekaphan.

    2017-01-01

    SrTi1-xNixO3 (x=0, 0.05, 0.10 and 0.15) nanoparticles were prepared by the hydrothermal method. All as-prepared samples were annealed at 800 °C for 3 h in argon to study the annealing effect on their magnetic properties. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray absorption near edge spectroscopy (XANES), X-ray photoelectron spectroscopy (XPS) and vibrating sample magnetometry (VSM) were used to study the crystalline structure, morphology, oxidation state and magnetic properties of samples. XRD results indicate a cubic perovskite structure of all samples with the impurity phase of SrCO3 in all as-prepared samples and Ni metal in annealed samples of x=0.10 and 0.15. SEM and TEM images confirmed a cubic shape for all samples with decreasing average particle sizes from 136.8±4.7 to 126.2±6.9 nm for annealed samples upon Ni doping. XANES results revealed the existence of Ni metal in sample of x=0.05 with the oxidation state of +2 for Ni ion in a SrTi0.95Ni0.05O3 sample. XPS results indicated the promotion of oxygen vacancies. VSM results revealed a paramagnetic behavior at room temperature of all as-prepared samples. Ni-doped samples exhibited ferromagnetic behavior after annealing in argon with the Curie temperature (TC) above 380 K for a sample with x=0.05 as shown by field cooling (FC) and zero-field cooling (ZFC) measurements. The room temperature ferromagnetism (RT-FM) of ferromagnetic samples was suggested to be originated from Ni metal and F-center exchange (FCE) mechanism due to the promotion of oxygen vacancies in the perovskite structure.

  11. Shape-control by microwave-assisted hydrothermal method for the synthesis of magnetite nanoparticles using organic additives

    Energy Technology Data Exchange (ETDEWEB)

    Rizzuti, Antonino [Politecnico di Bari, Dipartimento di Ingegneria Civile, Ambientale, del Territorio, Edile e di Chimica (Italy); Dassisti, Michele [Politecnico di Bari, Dipartimento di Meccanica, Management e Matematica (Italy); Mastrorilli, Piero, E-mail: p.mastrorilli@poliba.it [Politecnico di Bari, Dipartimento di Ingegneria Civile, Ambientale, del Territorio, Edile e di Chimica (Italy); Sportelli, Maria C.; Cioffi, Nicola; Picca, Rosaria A. [Università di Bari, Dipartimento di Chimica (Italy); Agostinelli, Elisabetta; Varvaro, Gaspare [Consiglio Nazionale delle Ricerche, Istituto di Struttura della Materia (Italy); Caliandro, Rocco [Consiglio Nazionale delle Ricerche, Istituto di Cristallografia (Italy)

    2015-10-15

    A simple and fast microwave-assisted hydrothermal method is proposed for the synthesis of magnetite nanoparticles. The addition of different surfactants (polyvinylpyrrolidone, oleic acid, or trisodium citrate) was studied to investigate the effect on size distribution, morphology, and functionalization of the magnetite nanoparticles. Microwave irradiation at 150 °C for 2 h of aqueous ferrous chloride and hydrazine without additives resulted in hexagonal magnetite nanoplatelets with a facet-to-facet distance of 116 nm and a thickness of 40 nm having a saturation magnetization of ∼65 Am{sup 2} kg{sup −1}. The use of polyvinylpyrrolidone led to hexagonal nanoparticles with a facet-to-facet distance of 120 nm and a thickness of 53 nm with a saturation magnetization of ∼54 Am{sup 2} kg{sup −1}. Additives such as oleic acid and trisodium citrate yielded quasi-spherical nanoparticles of 25 nm in size with a saturation magnetization of ∼70 Am{sup 2} kg{sup −1} and spheroidal nanoparticles of 60 nm in size with a saturation magnetization up to ∼82 Am{sup 2} kg{sup −1}, respectively. A kinetic control of the crystal growth is believed to be responsible for the hexagonal habit of the nanoparticles obtained without additive. Conversely, a thermodynamic control of the crystal growth, leading to spheroidal nanoparticles, seems to occur when additives which strongly interact with the nanoparticle surface are used. A thorough characterization of the materials was performed. Magnetic properties were investigated by Superconducting Quantum Interference Device and Vibrating Sample magnetometers. Based on the observed magnetic properties, the magnetite obtained using citrate appears to be a promising support for magnetically transportable catalysts.

  12. A Method for Detection of Trace Concentrations of Underivatized Amino Acid in Hydrothermal Fluids by Ion-Pairing Reversed-Phase UPLC-ESI-QTOF-MS

    OpenAIRE

    Konn, Cecile; Magner, Jörgen; Charlou, Jean-luc; Holm, Nils G.; Alsberg, Tomas

    2015-01-01

    Investigation of amino acids in hydrothermal systems is of prime importance for the understanding of geochemistry and microbiology of hydrothermal vents and plumes, for carbon and metals global cycles, for metabolism of some hydrothermal microorganisms and for the origin of life issue. Extensive theoretical and experimental work on amino acids behaviour in hydrothermal fluids has been done, conversely only few data exist on natural samples. Because each hydrothermal vent is unique, the more d...

  13. Hydrothermal Treatment (HTT) of Microalgae: Evaluation of the Process As Conversion Method in an Algae Biorefinery Concept

    NARCIS (Netherlands)

    Garcia Alba, L.; Torri, C.; Samori, C.; Spek, van der J.J.; Fabbri, D.; Kersten, S.R.A.; Brilman, D.W.F.

    2012-01-01

    The hydrothermal treatment (HTT) technology is evaluated for its potential as a process to convert algae and algal debris into a liquid fuel, within a sustainable algae biorefinery concept in which, next to fuels (gaseous and liquid), high value products are coproduced, nutrients and water are recyc

  14. Hydrothermal Treatment (HTT) of Microalgae: Evaluation of the Process As Conversion Method in an Algae Biorefinery Concept

    NARCIS (Netherlands)

    Garcia Alba, Laura; Torri, C.; Samori, C.; van der Spek, J.J.; Fabbri, D.; Kersten, Sascha R.A.; Brilman, Derk Willem Frederik

    2012-01-01

    The hydrothermal treatment (HTT) technology is evaluated for its potential as a process to convert algae and algal debris into a liquid fuel, within a sustainable algae biorefinery concept in which, next to fuels (gaseous and liquid), high value products are coproduced, nutrients and water are

  15. Characterization methods for an accelerator based fast-neutron facility

    Science.gov (United States)

    Franklyn, C.; Daniels, G. C.

    2012-02-01

    A fast neutron facility provides a number of complexities in both detection and shielding, the latter arising not only due to uncertainty in the behaviour of the scattered radiation (neutron and gamma-rays) from a fast neutron source, but also on shielding requirements that have to take into account internal and external factors, such as dose limitations, space availability for implementing bulky shielding and secondary interactions of the radiation with materials. This has possible influence on experimental measurements with a low signal to noise ratio. This paper reports on some of the investigations performed at a RFQ accelerator facility generating > 1011 neutrons per second with energies up to 14 MeV, which are used to perform fast neutron radiography studies. Areas highlighted are the neutron cross section libraries, where important data needs to be reviewed or updated.

  16. Microstructure and magnetic properties of MFe{sub 2}O{sub 4} (M = Co, Ni, and Mn) ferrite nanocrystals prepared using colloid mill and hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wei, E-mail: wangwei@mail.buct.edu.cn; Ding, Zui; Zhao, Xiruo [State Key Laboratory of Chemical Resource Engineering and School of Science, Beijing University of Chemical Technology, Beijing 100029 (China); Beijing Key Laboratory of Environmentally Harmful Chemical Analysis, Beijing University of Chemical Technology, Beijing 100029 (China); Wu, Sizhu [State Key Laboratory of Organic–Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Li, Feng [State Key Laboratory of Chemical Resource Engineering and School of Science, Beijing University of Chemical Technology, Beijing 100029 (China); Yue, Ming [College of Materials Science and Engineering, Beijing University of Technology, Beijing 100022 (China); Liu, J. Ping [Department of Physics, University of Texas at Arlington, Arlington, Texas 76019 (United States)

    2015-05-07

    Three kinds of spinel ferrite nanocrystals, MFe{sub 2}O{sub 4} (M = Co, Ni, and Mn), are synthesized using colloid mill and hydrothermal method. During the synthesis process, a rapid mixing and reduction of cations with sodium borohydride (NaBH{sub 4}) take place in a colloid mill then through a hydrothermal reaction, a slow oxidation and structural transformation of the spinel ferrite nanocrystals occur. The phase purity and crystal lattice parameters are estimated by X-ray diffraction studies. Scanning electron microscopy and transmission electron microscopy images show the morphology and particle size of the as-synthesized ferrite nanocrystals. Raman spectrum reveals active phonon modes at room temperature, and a shifting of the modes implies cation redistribution in the tetrahedral and octahedral sites. Magnetic measurements show that all the obtained samples exhibit higher saturation magnetization (M{sub s}). Meanwhile, experiments demonstrate that the hydrothermal reaction time has significant effects on microstructure, morphologies, and magnetic properties of the as-synthesized ferrite nanocrystals.

  17. Controlled synthesis of Ce(OH)CO3 flowers by a hydrothermal method and their thermal conversion to CeO2 flowers

    Institute of Scientific and Technical Information of China (English)

    Dongen Zhang; Feng Li; Jian Gu; Qing Xie; Shanzhong Li; Xiaobo Zhang; Guiquan Han; Ailing Ying; Zhiwei Tong

    2012-01-01

    Highly uniform Ce(OH)CO3 flowers were successfully prepared in large quantities using a facile hydrothermal approach from the reaction of Ce(NH4)(NO3)4 with CO(NH2)2 at 160 ℃ in a water-N2H4 complex,The influences of the N2H4 content and temperature on flower formation were discussed.CeO2 flowers were prepared by thermal conversion of Ce(OH)CO3 flowers at 500 ℃ in air.Both Ce(OH)CO3 and CeO2 flowers were characterized by X-ray powder diffraction (XRD),and scanning electron microscopy (SEM),The UV-vis adsorption spectrum of the CeO2 flowers showed that the band gap energy (Eg) is 2.66 eV,which is lower than that of bulk ceria.

  18. Optical and Morphological Properties of ZnO- and TiO2-Derived Nanostructures Synthesized via a Microwave-Assisted Hydrothermal Method

    OpenAIRE

    2012-01-01

    A microwave-assisted hydrothermal method was used to synthesize ZnO and TiO2 nanostructures. The experimental results show that the method resulted in crystalline monodispersed ZnO nanorods that have pointed tips with hexagonal crystal phase. TiO2 nanotubes were also formed with minimum bundles. The mechanism for the formation of the tubes was validated by HRTEM results. The optical properties of both ZnO and TiO2 nanostructures showed characteristics of strong quantum confinement regime. The...

  19. Optical and Morphological Properties of ZnO- and TiO2-Derived Nanostructures Synthesized via a Microwave-Assisted Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Nosipho Moloto

    2012-01-01

    Full Text Available A microwave-assisted hydrothermal method was used to synthesize ZnO and TiO2 nanostructures. The experimental results show that the method resulted in crystalline monodispersed ZnO nanorods that have pointed tips with hexagonal crystal phase. TiO2 nanotubes were also formed with minimum bundles. The mechanism for the formation of the tubes was validated by HRTEM results. The optical properties of both ZnO and TiO2 nanostructures showed characteristics of strong quantum confinement regime. The photoluminescence spectrum of TiO2 nanotubes shows good improvement from previously reported data.

  20. Method for Standardizing Sonic-Boom Model Pressure Signatures Measured at Several Wind-Tunnel Facilities

    Science.gov (United States)

    Mack, Robert J.

    2007-01-01

    Low-boom model pressure signatures are often measured at two or more wind-tunnel facilities. Preliminary measurements are made at small separation distances in a wind tunnel close at hand, and a second set of pressure signatures is measured at larger separation distances in a wind-tunnel facility with a larger test section. In this report, a method for correcting and standardizing the wind-tunnel-measured pressure signatures obtained in different wind tunnel facilities is presented and discussed.

  1. 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.

  2. 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.

  3. Preparation and Characterization of Novel Fe2O3-Flaky Coated Carbon Fiber by Electrospinning and Hydrothermal Methods

    Directory of Open Access Journals (Sweden)

    Qing-Yun Chen

    2014-01-01

    Full Text Available A novel hierarchical nanostructure of Fe2O3-flaky coated carbon fibers was produced by the electrospinning process followed by a hydrothermal technique. First, electrospinning of a colloidal solution that consisted of ferric nitrate and polyacrylonitrile (PAN was performed to produce PAN nanofibers. Then electrospun nanofiber was stabilized and calcinated in nitrogen at 800°C for 2 h to produce carbon nanofibers (CNFs which were exploited to produce Fe2O3-flaky structure using hydrothermal technique. The as-obtained products were characterized by scanning electron microscopy (SEM and X-ray diffraction (XRD. The results revealed that Fe2O3 flakes were successfully grown on the CNFs substrates, and the coverage of Fe2O3 flakes could be controlled by simply adjusting the hydrothermal pH value and time. Fe2O3-flaky coated carbon fibers displayed high photocatalytic activity toward degradation of methyl orange (MO under visible light irradiation.

  4. Synthesis of Mg{sub 2}SiO{sub 4}:Dy{sup 3+} nanoparticles by hydrothermal method and investigation of their thermo and photo luminescence properties

    Energy Technology Data Exchange (ETDEWEB)

    Ghahari, M., E-mail: maghahari@icrc.ac.ir [Department of Nanomaterials & Nanocoatings, Institute for Color Science and Technology (ICST), Tehran (Iran, Islamic Republic of); Mostafavi, K. [Department of Materials Engineering, Science and Research branch, Islamic Azad University, Tehran (Iran, Islamic Republic of)

    2016-05-15

    Highlights: • Mg{sub 2}SiO{sub 4}:Dy{sup 3+} nanoparticles have been prepared by hydrothermal and combustion methods. • Thermo and photo luminescent behavior of Mg{sub 2}SiO{sub 4}:Dy{sup 3+} was studied. • The effect of synthesis method on TL properties of Mg{sub 2}SiO{sub 4}:Dy{sup 3+} was investigated. • The optimal dopant concentration for thermo-luminescent property was obtained. - Abstract: In this study, photo and thermo-luminescent properties of Nano crystalline Mg{sub 2}SiO{sub 4}:Dy{sup 3+} prepared by a hydrothermal method were studied and compared to those of nanoparticles prepared by combustion method. The synthesized sample was characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy and photoluminescence spectroscopy. The effect of Dy concentration on photo and thermoluminescent intensities was studied. The X-ray diffraction (XRD) patterns of the samples revealed that forsterite was formed as a major phase for all the samples. The crystallite size was found to be in the range of 20–50 nm. The thermo luminescent glow curve indicated that the hydrothermal sample was more efficient than the combustion sample. Two prominent TL bands located at 200 nm and 320 nm were recorded. The prepared nanoparticles exhibited a roughly linear dose response to absorbed dose of 1000 Gy received from 60Co gamma source, suggesting that nanomaterial could be a good candidate for high dose dosimetry.

  5. Classification and methodical features of fitness and wellness facilities

    Directory of Open Access Journals (Sweden)

    Beliak Yu. I.

    2014-11-01

    Full Text Available Purpose : health and fitness use a large arsenal of different sports and physical activity. Development of fitness industry promotes its expansion and requires classification and methodological features that lead to the use of appropriate fitness programs. Material : more than 60 literature and video of 42 prestigious international fitness - conventions lessons were analyzed. Results : the evolution of species fitness and wellness, as well as the character used in those funds. Conclusions : as a means of improving classification attribute fitness appropriate to use their orientation, according to which they are divided into aerobic, strength exercises that promote flexibility and psychomotor coordination. The main methodological features fitness facilities are highlighted: the variety and interchangeability, clear regulation, the ability to transform, to exercise a selective effect on the body, the ability to solve a wide range of tasks, innovation.

  6. Early test facilities and analytic methods for radiation shielding: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Ingersoll, D T [comp.; Oak Ridge National Lab., TN (United States); Ingersoll, J K [comp.; Tec-Com, Knoxville, TN (United States)

    1992-11-01

    This report represents a compilation of eight papers presented at the 1992 American Nuclear Society/European Nuclear Society International Meeting. The meeting is of special significance since it commemorates the fiftieth anniversary of the first controlled nuclear chain reaction. The papers contained in this report were presented in a special session organized by the Radiation Protection and Shielding Division in keeping with the historical theme of the meeting. The paper titles are good indicators of their content and are: (1) The origin of radiation shielding research: The Oak Ridge experience, (2) Shielding research at the hanford site, (3) Aircraft shielding experiments at General Dynamics Fort Worth, 1950-1962, (4) Where have the neutrons gone , a history of the tower shielding facility, (5) History and evolution of buildup factors, (6) Early shielding research at Bettis atomic power laboratory, (7) UK reactor shielding: then and now, (8) A very personal view of the development of radiation shielding theory.

  7. Preparation of Artificial Zeolite from Fly Ash by Two-step Hydrothermal Method%粉煤灰两步水热法制备人工沸石

    Institute of Scientific and Technical Information of China (English)

    王海龙; 徐中慧; 吴丹丹; 谭钦文; 谢羽佳; 李春林

    2013-01-01

    Artificial zeolite was prepared by two-step hydrothermal method using fly ash as raw material.The analysis results of SEM,XRD and X-ray fluorescence spectrometry show that:The artificial zeolite product is pure,its structure is mainly Na-A type and a few 13X type,its major chemical compositions are SiO2 and A12O3.This indicates that the two-step hydrothermal method can overcome the shortcomings of traditional hydrothermal method with lots of impurities.The simulated wastewater with 50.00 mg/L of Mn2+ mass concentration was treated with the artificial zeolite product.After 125 min of adsorption,the Mn2+removal rate is 98.19% and the mass concentration of Mn2+ in the treated wastewater is 0.90 mg/L.%以粉煤灰为原料,采用两步水热法制备人工沸石.SEM、XRD、X射线荧光光谱分析结果表明:制得的人工沸石纯度较高,主要为Na-A型沸石和少量13X型沸石,主要化学成分为SiO2和A12O3.说明采用两步法制备人工沸石克服了传统水热法杂质含量高的缺陷.采用人工沸石处理初始Mn2+质量浓度为50.00 mg/L的模拟含锰废水,吸附125 min后,Mn2+去除率达98.19%,模拟废水中剩余Mn2+质量浓度为0.90 mg/L.

  8. A facile and green method for synthesis of reduced graphene oxide/Ag hybrids as efficient surface enhanced Raman scattering platforms.

    Science.gov (United States)

    Huang, Qingli; Wang, Jiaming; Wei, Wenxian; Yan, Qiuxiang; Wu, Changle; Zhu, Xiashi

    2015-01-01

    Reduced graphene oxide/Ag nanoparticles hybrids (rGO/AgNPs) were fabricated via a green and facile hydrothermal method. The as-synthesized materials were characterized in detail using various spectroscopic and microscopic techniques. Under a suitable dosage of silver ions, well-dispersed AgNPs on the reduced graphene oxide sheets were obtained. The surface plasmon resonance properties of AgNPs on graphene show that there is an interaction between AgNPs and graphene. Trace detection of organic dyes is studied based on rGO/AgNPs hybrids as efficient surface enhanced Raman scattering platforms. It has been found that the suitable experiment parameter is crucial to trace detection of organic dyes molecules. This work is of importance in the practical application in device-design based on the SERS effect of noble metal/reduced oxide graphene (or oxide graphene) hybrids. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. 系列纳米结构锰氧化物的水热合成%Synthesis of Various Nanostructured Manganese Oxides via Facile Hydrothermal Reaction

    Institute of Scientific and Technical Information of China (English)

    杨则恒; 周晨旭; 宋新民; 张卫新; 张娜

    2008-01-01

    以KMnO4为锰源、抗坏血酸(AA)为还原剂,采用水热法制备系列纳米结构锰氧化物.通过调节反应物的物质的量的比、水溶液的pH值、反应温度和反应时间,制备出了不同纳米结构的锰氧化物,包括Mn3O4纳米粒子、MnOOH、α-MnO2和β-MnO2纳米棒.采用XRD和TEM测试技术对合成产物进行了表征,同时对其反应机理进行了探讨.%A versatile hydrothermal reaction between KMnO4 and ascorbic acid (AA) was developed to synthesizemanganese compounds. A variety of nanostructured manganese oxides including Mn3O4 nanoparticles, MnOOH, α-MnO2 and β-MnO2 nanorods have been prepared through adjusting the molar ratio of the reactants, pH value of theaqueous solution, reaction temperature and reaction time. The products were characterized by X-ray powderdiffraction(XRD) and transmission electron microscopy(TEM). The possible reaction mechanism was discussed.

  10. 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.

  11. Facile hydrothermal synthesis of dendritic Cu2S nanostructures using novel starting reagents and investigation of their behavior in solar cells

    Science.gov (United States)

    Shobeiri, Seyed Amin; Mousavi-Kamazani, Mehdi; Rahmatolahzadeh, Reza; Motevalli, Kourosh

    2017-05-01

    In the present study, dendritic Cu2S nanostructures were successfully synthesized via a simple hydrothermal route using cysteine as a capping agent, sulfide source, and reducing agent for converting Cu2+ to Cu+ and [Cu(en)2(H2O)2]Cl2 complex as a new copper precursor. The effect of temperature, reaction time, and cysteine concentration on the morphology and particle size was also investigated. Moreover, efficiency of as-synthesized Cu2S nanostructures in thin-film solar cells was evaluated. The results showed that particle size and morphology have salient effect on solar cells efficiency and dendritic Cu2S nanostructures have higher efficiency compared to spherical and rod-like Cu2S nanostructures. In addition, depositing of dendritic Cu2S on Cu2S nanoparticles led to obtaining 3.02% cell efficiency that in comparison with sole dendritic nanostructures (2.15%) and sole nanoparticles (1.62%), efficiency improvements of 40 and 86% were, respectively, achieved.

  12. Structural and electrical properties of TiO{sub 2}/ZnO core–shell nanoparticles synthesized by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Vlazan, P.; Ursu, D.H. [National Institute for Research and Development in Electrochemistry and Condensed Matter, Department of Condensed Matter, 1 Plautius Andronescu St., 300224 Timisoara (Romania); Irina-Moisescu, C. [Faculty of Industrial Chemistry and Environmental Engineering, “Politehnica” University of Timisoara, 6 Vasile Parvan Avenue, 300223 Timisoara (Romania); Miron, I., E-mail: mironiasmina@gmail.com [National Institute for Research and Development in Electrochemistry and Condensed Matter, Department of Condensed Matter, 1 Plautius Andronescu St., 300224 Timisoara (Romania); Sfirloaga, P. [National Institute for Research and Development in Electrochemistry and Condensed Matter, Department of Condensed Matter, 1 Plautius Andronescu St., 300224 Timisoara (Romania); Faculty of Physics, West University of Timisoara, 4 Vasile Parvan Avenue, 300223 Timisoara (Romania); Rusu, E. [Institute of Electronic Engineering and Nanotechnologies, “D. Ghiţu” of the Academy of Sciences of Moldova, Academiei str. 3, Chisinau MD-2028, Academiei str. 3, Chisinau MD-2028 (Moldova, Republic of)

    2015-03-15

    TiO{sub 2}/ZnO core–shell nanoparticles were successfully synthesized by hydrothermal method in two stages: first stage is the hydrothermal synthesis of ZnO nanoparticles and second stage the obtained ZnO nanoparticles are encapsulated in TiO{sub 2}. The obtained ZnO, TiO{sub 2} and TiO{sub 2}/ZnO core–shell nanoparticles were investigated by means of X-ray diffraction, transmission electron microscopy, Brunauer, Emmett, Teller and resistance measurements. X-ray diffraction analysis revealed the presence of both, TiO{sub 2} and ZnO phases in TiO{sub 2}/ZnO core–shell nanoparticles. According to transmission electron microscopy images, ZnO nanoparticles have hexagonal shapes, TiO{sub 2} nanoparticles have a spherical shape, and TiO{sub 2}/ZnO core–shell nanoparticles present agglomerates and the shape of particles is not well defined. The activation energy of TiO{sub 2}/ZnO core–shell nanoparticles was about 101 meV. - Graphical abstract: Display Omitted - Highlights: • TiO{sub 2}/ZnO core–shell nanoparticles were synthesized by hydrothermal method. • TiO{sub 2}/ZnO core–shell nanoparticles were investigated by means of XRD, TEM and BET. • Electrical properties of TiO{sub 2}/ZnO core–shell nanoparticles were investigated. • The activation energy of TiO{sub 2}/ZnO core–shell nanoparticles was about E{sub a} = 101 meV.

  13. Spectroscopic and structural properties of Na{sub 3}RE(PO{sub 4}){sub 2}:Yb orthophosphates synthesised by hydrothermal method (RE = Y, Gd)

    Energy Technology Data Exchange (ETDEWEB)

    Godlewska, P.; Matraszek, A. [Wrocław University of Economics, Faculty of Chemistry and Food Technology, ul. Komandorska 118/120, 53-345 Wrocław (Poland); Macalik, L., E-mail: L.Macalik@int.pan.wroc.pl [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, ul. Okólna 2, 50-422 Wrocław (Poland); Hermanowicz, K.; Ptak, M.; Tomaszewski, P.E. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, ul. Okólna 2, 50-422 Wrocław (Poland); Hanuza, J. [Wrocław University of Economics, Faculty of Chemistry and Food Technology, ul. Komandorska 118/120, 53-345 Wrocław (Poland); Institute of Low Temperature and Structure Research, Polish Academy of Sciences, ul. Okólna 2, 50-422 Wrocław (Poland); Szczygieł, I. [Wrocław University of Economics, Faculty of Chemistry and Food Technology, ul. Komandorska 118/120, 53-345 Wrocław (Poland)

    2015-04-15

    Highlights: • Na{sub 3}RE(PO{sub 4}){sub 2}, RE = Y or Gd, doped with Yb{sup 3+} were synthesised by the hydrothermal method. • As-synthesised samples crystallise in the trigonal modification. • After calcination at 500 °C they transform to monoclinic (Y) or orthorhombic (Gd) symmetry. • Morphology of the particles for all samples is similar and resembles rice grains. • The decay time of Yb{sup 3+} increases when the orthophosphate precursor is calcined at 700 °C. - Abstract: Na{sub 3}RE(PO{sub 4}){sub 2} orthophosphates, where RE = Y and Gd, doped with Yb{sup 3+} ions were synthesised by hydrothermal method and characterised by X-ray diffraction, microscopic, IR and Raman techniques. The emission, excitation spectra were recorded at room temperature and fluorescence decay time was determined. As-synthesised samples crystallise in a trigonal modification and during calcination at 500 °C they transform to a monoclinic or orthorhombic symmetry (for yttrium and gadolinium compounds, respectively). Finally, the samples calcined at 700 °C do not reveal the trigonal symmetry. The morphology of particles for all samples is similar and resembles rice grains. All the obtained for the studied orthophosphates data were compared to those previously reported for the same compounds synthesised by Pechini method.

  14. Hydrothermal Biogeochemistry

    Science.gov (United States)

    Shock, E.; Havig, J.; Windman, T.; Meyer-Dombard, D.; Michaud, A.; Hartnett, H.

    2006-12-01

    Life in hot spring ecosystems is confronted with diverse challenges, and the responses to those challenges have dynamic biogeochemical consequences over narrow spatial and temporal scales. Within meters along hot spring outflow channels at Yellowstone, temperatures drop from boiling, and the near-boiling conditions of hot chemolithotrophic communities, to those that permit photosynthesis and on down to conditions where nematodes and insects graze on the edges of photosynthetic mats. Many major and trace element concentrations change only mildly in the water that flows through the entire ecosystem, while concentrations of other dissolved constituents (oxygen, sulfide, ammonia, total organic carbon) increase or decrease dramatically. Concentrations of metals and micronutrients range from toxic to inadequate for enzyme synthesis depending on the choice of hot spring. Precipitation of minerals may provide continuous growth of microbial niches, while dissolution and turbulent flow sweeps them away. Consequently, microbial communities change at the meter scale, and even more abruptly at the photosynthetic fringe. Isotopic compositions of carbon and nitrogen in microbial biomass reflect dramatic and continuous changes in metabolic strategies throughout the system. Chemical energy sources that support chemolithotrophic communities can persist at abundant or useless levels, or change dramatically owing to microbial activity. The rate of temporal change depends on the selection of hot spring systems for study. Some have changed little since our studies began in 1999. Others have shifted by two or more units in pH over several years, with corresponding changes in other chemical constituents. Some go through daily or seasonal desiccation cycles, and still others exhibit pulses of changing temperature (up to 40°C) within minutes. Taken together, hydrothermal ecosystems provide highly manageable opportunities for testing how biogeochemical processes respond to the scale of

  15. Non-enzymatic hydrogen peroxide biosensor based on rose-shaped FeMoO{sub 4} nanostructures produced by convenient microwave-hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hongying, E-mail: liuhongying@hdu.edu.cn [College of Life Information Science & Instrument Engineering, Hangzhou Dianzi University, Zhejiang, Hangzhou 310018 (China); Gu, Chunchuan [Department of Clinical Laboratory, Hangzhou Cancer Hospital, Zhejiang, Hangzhou 310002 (China); Li, Dujuan; Zhang, Mingzhen [College of Life Information Science & Instrument Engineering, Hangzhou Dianzi University, Zhejiang, Hangzhou 310018 (China)

    2015-04-15

    Graphical abstract: A non-enzymatic H{sub 2}O{sub 2} sensor with high selectivity and sensitivity based on rose-shaped FeMoO{sub 4} synthesized by the convenient microwave-assisted hydrothermal method, was fabricated. - Highlights: • Rose-shaped FeMoO{sub 4} is synthesized within 10 min via microwave-assisted hydrothermal approach. • Non-enzymatic hydrogen peroxide biosensor based on FeMoO{sub 4} nanomaterials is fabricated. • The biosensor exhibits good performance. - Abstract: In this work, we demonstrated a simple, rapid and reliable microwave-assisted hydrothermal approach to synthesize the uniform rose-shaped FeMoO{sub 4} within 10 min. The morphologies of the synthesized materials were characterized by X-ray powder diffraction and scanning electron microscopy. Moreover, a non-enzymatic amperometric sensor for the detection of hydrogen peroxide (H{sub 2}O{sub 2}) was fabricated on the basis of the FeMoO{sub 4} as electrocatalysis. The resulting FeMoO{sub 4} exhibited high sensitivity and good stability for the detection of H{sub 2}O{sub 2}, which may be attributed to the rose-shaped structure of the material and the catalytic property of FeMoO{sub 4}. Amperometric response showed that the modified electrode had a good response for H{sub 2}O{sub 2} with a linear range from 1 μM to 1.6 mM, a detection limit of 0.5 μM (S/N = 3), high selectivity and short response time. Additionally, good recoveries of analytes in real milk samples confirm the reliability of the prepared sensor in practical applications.

  16. Polarization reversal in BaTiO{sub 3} nanostructures synthesized by microwave-assisted hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Velasco-Davalos, Ivan; Ambriz-Vargas, Fabian [Centre Énergie, Matériaux et Télécommunications, INRS, 1650 Lionel-Boulet, Varennes, Québec J3X1S2 (Canada); Gómez-Yáñez, Carlos [Departamento de Ingeniería en Metalurgia y Materiales, ESIQIE, Instituto Politécnico Nacional, UPALM, Zacatenco, CP 07738 DF, México (Mexico); Thomas, Reji, E-mail: reji.thomas@emt.inrs.ca [Centre Énergie, Matériaux et Télécommunications, INRS, 1650 Lionel-Boulet, Varennes, Québec J3X1S2 (Canada); Ruediger, Andreas, E-mail: ruediger@emt.inrs.ca [Centre Énergie, Matériaux et Télécommunications, INRS, 1650 Lionel-Boulet, Varennes, Québec J3X1S2 (Canada)

    2016-05-15

    Ferroelectric BaTiO{sub 3} nanostructures and thin films were deposited by a microwave assisted hydrothermal process at low temperatures (<250 °C) on metallic Pt/Al{sub 2}O{sub 3}/SiO{sub 2}/Si and Nb:SrTiO{sub 3} (100) substrates. TiO{sub 2} nanoparticles dispersed in the Ba(OH){sub 2} alkaline solution are used as the precursors without any mineralizers. The incorporation of H{sub 2}O{sub 2} into precursor solution served as a strong oxidant and catalyst for the uniform nucleation of BaTiO{sub 3} on the substrate surface. The polycrystalline and epitaxial nature of the films were confirmed by atomic force microscopy and x-ray diffraction studies. We report the ferroelectric behavior of BaTiO{sub 3} films on Nb:SrTiO{sub 3} (100) substrates by piezoresponse force microscopy. - Highlights: • Microwave assisted hydrothermal deposition of highly ordered BaTiO{sub 3} thin films on single crystal substrates. • Fast growth without the needof any mineralizers. • Moderate addition of H{sub 2}O{sub 2} significantly improves the surface coverage. • H{sub 2}O{sub 2} substantially reduces hydrogen incorporation into the film and the associated leakage current. • Out-of-plane polarization reversal demonstrated locally.

  17. LPG sensing properties of SnO2 nanoparticles doped with several metal oxides by a hydrothermal method

    Science.gov (United States)

    Hien Vu, Xuan; Ly, Tu Huy Anh; Khuc, Quang Trung; Vuong Dang, Duc; Chien Nguyen, Duc

    2010-06-01

    CuO, Al2O3, Ag2O and La2O3 doped on SnO2 nanoparticles were successfully fabricated by a hydrothermal route at 200 °C for 3 h. The morphology and composition were characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and energy dispersive x-ray analysis (EDX). The results showed that the particle size is 6-8 nm without other impurities. The influence of CuO with a concentration of 0.5-3wt%, which was doped on sol SnO2 5wt% by hydrothermal and vibration technique, was discussed. In addition, the gas sensitivity experiment of samples to 1% LPG in the temperature range of 230-430 °C indicated the improvement in sensitivity and response time. In particular, the SnO2 sol suspension 5wt% doped with CuO 2wt% showed the best sensitivity at 330 °C.

  18. Hydrothermal treatment and enzymatic hydrolysis of Tamarix ramosissima: evaluation of the process as a conversion method in a biorefinery concept.

    Science.gov (United States)

    Xiao, Ling-Ping; Shi, Zheng-Jun; Xu, Feng; Sun, Run-Cang

    2013-05-01

    The present work investigated the effects of hydrothermal treatment (HTT) of Tamarix ramosissima by determination of sugar and inhibitor formation in the liquid fraction, and chemical and morphological changes of the pretreated solid material coupled with an evaluation of enzymatic hydrolysis. HTT was carried out in a batch reactor system at a maximal temperature (TMAX 180-240 °C) and evaluated for severities logRo ranging from 2.40 to 4.17. The liquid fractions were analyzed by HPLC, GPC, and GC-MS. The morphology and composition of the solid residues were characterized using an array of techniques, such as SEM, XRD, BET surface area, and CP/MAS (13)C NMR. Using a variety of tools, we have developed a better understanding of how HTT process affects biomass structure and cellulose properties that impact on its digestibility. These results provided new insights into the factors limiting enzymatic digestibility and mechanism of biomass deconstruction during hydrothermal process. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  19. Temperature Effect of Crystalinity in Cellulose Nanocrystal from Oil Palm Empty Fruit Bunch (OPEFB using Sonication-Hydrothermal Methods

    Directory of Open Access Journals (Sweden)

    Zulnazri

    2017-01-01

    Full Text Available Production of cellulose nanocrystals (CNCs from cellulose of oil palm empty fruit bunches (OPEFB have been done. The delignification of OPEFB was mixed with 17,5% NaOH and carried out in the three-neck flask with refluxed for 2 hour at 80oC. Further the suspension was bleached with NaOCl 2% for 1 hour at 70oC. Then, to produce CNCs, Cellulose was firstly sonicated for 30 minutes at 40oC. After that cellulose was hydrolized at hydrothermal reactor for 0,1,2,3,4,5, hours at 110 and 120oC respectively. After filtration and washing, CNCs was analyzed by X-Ray Diffraction and the result shows that the grade of the highest CNCs crystalinity at consentration of HCL 2 M at a temperature of 110oC with reaction time of 2 hours is equal to 75.87%. It can be concluded that sonication-hydrothermal can increase the grade of crystalinity of cellulose nanocrystal.

  20. Effect of the H2 plasma treatment of a seed layer on the synthesis of ZnO nanorods using a microwave hydrothermal method

    Science.gov (United States)

    Koo, Horng-Show; Lin, Ching-Cheng; Chen, Yao-Ju; Peng, Cheng-Hsiung; Chen, Mi

    2014-01-01

    The effect of H2 plasma treatment of a seed layer on the synthesis and characterization of zinc oxide (ZnO) nanorods is determined. Using an Al-doped ZnO (AZO) thin film as a seed layer, well-aligned ZnO nanorods are rapidly grown on an indium tin oxide (ITO)-coated glass substrate using a microwave hydrothermal method. The deposited AZO substrate was previously treated with H2 plasma. The effect of H2 plasma treatment of the seed layer on the alignment, growth rate, and crystallinity of the ZnO nanorods is determined. It is shown that the alignment and growth rate of the ZnO nanorods depend on the characteristics and roughness of the seed layer, which are improved by H2 plasma treatment. Various characterization methods such as X-ray diffraction (XRD), cathodoluminescence (CL), transmission electron microscopy (TEM), and X-ray photoemission spectroscopy (XPS) are used to determine the characteristic quality of the ZnO nanorods. A fundamental model of the effect of H2 plasma treatment on the seed layer and ZnO growth using a microwave hydrothermal process is also presented.

  1. Using the hydrothermal method to grow p-type ZnO nanowires on Al-doped ZnO thin film to fabricate a homojunction diode.

    Science.gov (United States)

    Tseng, Yung-Kuan; Hung, Meng-Chun; Su, Shun-Lung; Li, Sheng-Kai

    2014-10-01

    In this study, the hydrothermal method is used to grow phosphorus-doped ZnO nanowires on Si/SiO2 substrates deposited with Al-doped ZnO thin film. This structure forms a homogeneous p-n junction. In this study, we are the pioneers to use ammonium hypophosphite (NH4H2PO2) as a source of phosphorus to prepare the precursor solution. Ammonium hypophosphite of different concentration levels is used to observe its effects on the growth of nanowires. The results show that the precursor solution prepared from ammonium hypophosphite can produce good crystalline ZnO nanowires while there is no linear relationship between the amounts and concentration levels of phosphorus doped into the nanowires. Whether the phosphorus-doped ZnO nanowires have the characteristics of a p-type semiconductor is indirectly verified by measuring whether the p-n junction made up of Al-doped ZnO thin film and phosphorus-doped ZnO nanowires shows rectifying behavior. I-V measurements are made on the specimens. The results show good rectifying behavior, proving that the phosphorus-doped ZnO nanowires and Al-doped AZO films have p-type and n-type semiconductor properties, constituting a good p-n junction. This result also proves that ammonium hypophosphite is a better source of phosphorus in the hydrothermal method to synthesize phosphorus-doped ZnO nanowires.

  2. Lithium manganese oxide (LiMn2O4) nanoparticles synthesized by hydrothermal method as adsorbent of lithium recovery process from geothermal fluid of Lumpur Sidoarjo

    Science.gov (United States)

    Noerochim, Lukman; Sapputra, Gede Panca Ady; Widodo, Amien

    2016-04-01

    Lumpur Sidoarjo is one of geothermal fluid types which has a great potential as source of lithium. Adsorption method with Lithium Manganese Oxide (LiMn2O4) as an adsorbent has been chosen for lithium recovery process due to low production cost and environmental friendly. LiMn2O4 was synthesized by hydrothermal method at 200 °C for 24 hrs, 48 hrs, and 72 hrs. As prepared LiMn2O4 powder is treated by acid treatment with 0.5 M HCl solution for 24 hrs. XRD test result reveals that all of as-prepared samples are indexed as spinel structure of LiMn2O4 (JCPDS card no 35-0782) with no impurity peaks detected. SEM images show that LiMn2O4 has nanoparticles morphology with particle size around 25 nm. The highest adsorption efficiency of adsorbent is obtained by sample hydrothermal for 72 hrs with 42.76%.

  3. Magnetic Properties for the Single-domain CoFe2O4 Nano-particles Synthesized by the Hydrothermal Method

    Institute of Scientific and Technical Information of China (English)

    YANG Zhi; ZHANG Yue; SONG Yu; WANG Jiawei; CHEN Yuang; ZHANG Zhe; DUAN Nian; RUAN Xuefeng

    2015-01-01

    The aim of this work was to investigate the size-related magnetism for the single-domain CoFe2O4 nano-particles synthesized using the hydrothermal method. The effects of the reaction temperature and the reaction time on the lattice constants, particle morphologies, and the room-temperature magnetic properties were studied from the X-ray diffraction, the transmission electron microscope, and the vibrating-sample magnetometer. The experimental results show that the samples are composed of CoFe2O4 nano-particles with an average crystallite size (D) smaller than 40 nm, and the magnetic properties of the samples can be manipulated in a wide range:the MS values vary from smaller than 50 emu/g to close to 80 emu/g, and the HC values are between about 200 Oe and 2000 Oe. Additionally, the relationship between HC and 1/D3/2 satisifes linearship, showing the characteristic of single-domain structure. These results indicate that the single-domain CoFe2O4 nano-particles with size controlled between the superparamagnetic critical size and single-domain critical size can be easily prepared using this hydrothermal method.

  4. One-pot fabrication of Co{sub 3}O{sub 4} microspheres via hydrothermal method at low temperature for high capacity supercapacitor

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Chao; Zhang, Jinfeng [State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China); Deng, Yida, E-mail: yida.deng@tju.edu.cn [School of Material Science and Engineering, Tianjin University, Tianjin 300072 (China); Zhong, Cheng [School of Material Science and Engineering, Tianjin University, Tianjin 300072 (China); Liu, Lei [State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China); Hu, Wenbin [State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China); School of Material Science and Engineering, Tianjin University, Tianjin 300072 (China)

    2015-09-15

    Highlights: • Take full advantage of the easily oxidized feature of cobalt (II) complexes ammonia. • Low temperature method was applied with absence of subsequent calcination process. • The Co{sub 3}O{sub 4} microspheres possess extraordinary electrochemical properties. - Abstract: Co{sub 3}O{sub 4} microspheres were successfully produced with one-step low temperature hydrothermal method and their electrochemical properties have been investigated. By means of utilizing easily oxidized characteristic of cobalt complexes ammonia, the Co{sub 3}O{sub 4} microspheres were synthesized for the first time with an extremely low hydrothermal temperature (100 °C). In the absent case of surfactant, these Co{sub 3}O{sub 4} microspheres with a diameter of ca. 500 nm and smooth surface were prepared with the assistance of nitrate. Influences concerning about temperature and concentration of nitrate on morphology and size distribution were thoroughly discussed. Electrochemical characterization indicated that the Co{sub 3}O{sub 4} microspheres exhibited high specific capacitance of 850, 780, 700, 630 F/g at current densities of 1, 2, 4, 8 A/g, respectively. And after 1000 cycles, the devices with Co{sub 3}O{sub 4} microspheres showed high charge/discharge reversibility with an efficiency of 90.8% at a current density of 2 A/g.

  5. Morphologically tuned 3D/1D rutile TiO2 hierarchical hybrid microarchitectures engineered by one-step surfactant free hydrothermal method

    Science.gov (United States)

    Maria John, Maria Angelin Sinthiya; Ramamurthi, K.; Sethuraman, K.; Ramesh Babu, R.

    2017-05-01

    Present investigation reports on the surfactant free hydrothermal synthesize of the morphologically tuned hierarchical hybrid rutile titanium oxide (TiO2) microarchitectures showing three dimensional microflower structures and cook pine tree like structures on the one dimensional nanorods formed over TiO2 seed layer coated glass substrates by tuning growth temperature. TiO2 seed layer of ∼100 nm thick was coated on the glass substrates employing sol-gel spin coating method and then rutile TiO2 microarchitectures were synthesized on the TiO2 seed layer by one-step surfactant free hydrothermal method. Deposited samples were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, UV-vis spectroscopy and photoluminescence spectroscopy techniques. Influence of the growth temperature on the crystallinity, morphology and optical properties along with the growth mechanism to achieve hierarchical microarchitectures was investigated. Present work revealed that the structural, morphological and optical properties of the TiO2 hierarchical microarchitectures strongly depend on the growth temperature. Further we proposed a model for the cause to effect possible morphological changes of rutile TiO2 microarchitectures as a function of growth temperatures on the TiO2 seeded glass substrates.

  6. Experimental optimization of a landmine detection facility using PGNAA method

    Institute of Scientific and Technical Information of China (English)

    Hashem MIRI-HAKIMABAD; Hamed PANJEH; Alireza VEJDANI-NOGHREIYAN

    2008-01-01

    The optimum moderator geometry increases the performance of prompt gamma neutron activation analysis (PGNAA) method considerably. In this work an 241Am-Be source was used in the moderator geometry for detecting buried landmines by PGNAA method. Experiments were done to find the best moderator geometry for the moderated 241 Am-Be source, by replacing the mine with a neutron detector and counting the thermal neutron flux. The flux of thermal neutrons at the place of mine was used as a determining factor to introduce the best moderator geometry.

  7. Facile Preparation Method for Inclusion Complexes between Amylose and Polytetrahydrofurans

    NARCIS (Netherlands)

    Rachmawati, Rachmawati; Woortman, Albert J. J.; Loos, Katja

    Several methods were used to investigate the possibility of preparing inclusion complexes between amylose and polytetrahydrofurans (PTHF) via direct mixing. Potato amylose (M-v similar to 200 kg/mol) and synthetic amylose (M-n 42 kg/mol) were complexed with PTHF having different molecular weights

  8. A Facile Spectrophotometric Method for the Determination of Iodate ...

    African Journals Online (AJOL)

    NJD

    2006-12-06

    Dec 6, 2006 ... thyroid hormones that play an important role in the develop- ment of brain .... of iodate. The proposed method, which is simple and rapid, ... 1 A.G. Gilman, L.S. Goodman, T.W. Rad and F. Murad, The Pharmacologi- cal Basis of ...

  9. Preparation of nanocrystalline composite TiO2-SnO2 powders using sol-gel method combined with hydrothermal treatment

    Directory of Open Access Journals (Sweden)

    Anna Marzec

    2016-12-01

    Full Text Available The paper describes the process of TiO2-SnO2 nanocomposites manufacturing utilizing two-step sol-gel method combined with calcination (in the case of titanium hydroxide gel or hydrothermal treatment (in the case of tin hydroxide. Phase composition of the obtained nanopowders and average crystallite sizes were determined using XRD analysis. Measurements of the specific surface area were performed using sorption method based on determination of physical adsorption isotherm (BET. Morphology of the nanopowders was observed using transmission electron microscope. The presented synthesis method enables to obtain composites nanopowders from TiO2-SnO2 system with known and controlled chemical and phase compositions, and distinctly diversified TiO2 and SnO2 particle sizes.

  10. Hydrothermal route to Eu doped LuO(OH) and Lu2O3 nanorods

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A facile method was developed to synthesize Eu doped LuO(OH) nanorods through hydrothermal processing and Lu2O3 nanorods by subsequent calcining.The microstructural morphologies of the Lu-based nanostructures could be controlled by simply varying the concentration of NaOH in hydrothermal processing as mineralizer.TEM observation revealed that the obtained LuO(OH) nanorods after hydrothermal processing had a uniform diameter of 10-25 nm and a length around 100 nm.After heat treatment at 600-700°C for 2 h,the high length/diameter ratio was sustained in the obtained Lu2O3 nanorods with different sizes depending on the calcining temperatures.

  11. A facile and efficient synthetic method for 4-phenylethynylphthalic anhydride

    Institute of Scientific and Technical Information of China (English)

    Di Feng Wu; Mei Jia Yang; Yang Wang; Guo Wei Gao; Jian Men

    2011-01-01

    A novel approach to the synthesis of 4-phenylethynylphthalic anhydride has been described. The target compound was synthesized by Pd/Cu catalyzed Sonogashira coupling reaction between phenylacetylene and 4-bromophthalic acid which was for the first time employed as start material, followed by dehydration of 4-phenylethynylphthalic acid. Compared with traditional synthetic routes, this method provides several advantages such as readily available raw materials, convenient manipulation and high yield. The products were characterized by IR, 1H NMR, 13C NMR, MS and elemental analysis, respectively.

  12. Composite titanium nitride layers produced on the AZ91D magnesium alloy by a hybrid method including hydrothermal modification of the layer

    Science.gov (United States)

    Tacikowski, M.; Grzonka, J.; Płociński, T.; Jakieła, R.; Pisarek, M.; Wierzchoń, T.

    2015-08-01

    The microstructure and properties of the composite TiN-Ti-Al type titanium nitride surface layer with a sub-layer of titanium and aluminium produced on AZ91D magnesium alloy using a hybrid PVD method including final sealing by hydrothermal treatment were investigated. The results were analysed in terms of the microstructure-properties correlation, to approach the role of the sub-layers and the mechanisms involved in the properties improvement. The microstructure investigations indicate that the composite titanium nitride layers are tight and have nano-crystalline, diffusive character and multi zone microstructure of the type TixOy-TiN-Ti-Al-Al3Mg2-Al12Mg17. The significant corrosion resistance improvement of the AZ91D alloy obtained using the sealed composite titanium nitride layers was found to be the result of a synergistic mechanism which combined hydrothermal treatment of the layer with an action of aluminium sub-layer which is critical to make the sealing effective. The diffusive bonding via Mg-Al zone improves adhesion and the load bearing capacity of titanium nitride layers in wear conditions.

  13. Reduced graphene oxide wrapped ZnS–Ag{sub 2}S ternary composites synthesized via hydrothermal method: Applications in photocatalyst degradation of organic pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Amaranatha Reddy, D.; Ma, Rory [Department of Chemistry and Chemical Institute for Functional Materials, Pusan National University, Busan 609-735 (Korea, Republic of); Choi, Myong Yong, E-mail: mychoi@gnu.ac.kr [Department of Chemistry and Research Institute of Natural Sciences, Gyeongsang National University, Jinju 660-701 (Korea, Republic of); Kim, Tae Kyu, E-mail: tkkim@pusan.ac.kr [Department of Chemistry and Chemical Institute for Functional Materials, Pusan National University, Busan 609-735 (Korea, Republic of)

    2015-01-01

    Highlights: • Hydrothermal synthesis of ternary ZnS–Ag{sub 2}S–RGO nanostructures without any additives. • Significant improvement of the photocatalytic activity in RGO wrapped composites. • Near white light emission and stable cycling can lead these composites to find application in near UV-white LEDs and environmental protection issues. - Abstract: In this work, we have successfully synthesized ternary nanohybrid composite, ZnS–Ag{sub 2}S wrapped with reduced graphene oxide (RGO) using hydrothermal method without any surfactant. We have accessed the photocatalytic ability of ZnS–Ag{sub 2}S–RGO nanocomposite using the oxidation of Rhodamine B (RhB) under simulated sunlight irradiation. The superior photocatalytic ability of ZnS–Ag{sub 2}S–RGO compared to bare ZnS, was ascribed to an efficient charge transfer from ZnS to Ag{sub 2}S and graphene sheets. The recyclability results also demonstrated the excellent stability and reliability of the ZnS–Ag{sub 2}S–RGO. In addition to the excellent photocatalytic degradation properties, the synthesized ZnS–Ag{sub 2}S–RGO nanocomposite exhibited near white light emission, which implies that careful design and control of the composition could be lead to find application in near UV-white LEDs. The present work provides new insights into the synthesis and characterizations of ternary ZnS–Ag{sub 2}S–RGO nanocomposites and its wide applications in the environmental protection issues.

  14. Synthesis of BiFeO3 thin films on single-terminated Nb : SrTiO3 (111 substrates by intermittent microwave assisted hydrothermal method

    Directory of Open Access Journals (Sweden)

    Ivan Velasco-Davalos

    2016-06-01

    Full Text Available We report on a simple and fast procedure to create arrays of atomically flat terraces on single crystal SrTiO3 (111 substrates and the deposition of ferroelectric BiFeO3 thin films on such single-terminated surfaces. A microwave-assisted hydrothermal method in deionized water and ammonia solution selectively removes either (SrO34− or Ti4+ layers to ensure the same chemical termination on all terraces. Measured step heights of 0.225 nm (d111 and uniform contrast in the phase image of the terraces confirm the single termination in pure and Nb doped SrTiO3 single crystal substrates. Multiferroic BiFeO3 thin films were then deposited by the same microwave assisted hydrothermal process on Nb : SrTiO3 (111 substrates. Bi(NO33 and Fe(NO33 along with KOH served as the precursors solution. Ferroelectric behavior of the BiFeO3 films on Nb : SrTiO3 (100 substrates was verified by piezoresponse force microscopy.

  15. Growth of raspberry-, prism- and flower-like ZnO particles using template-free low-temperature hydrothermal method and their application as humidity sensors

    Science.gov (United States)

    Pál, Edit; Hornok, Viktória; Kun, Robert; Chernyshev, Vladimir; Seemann, Torben; Dékány, Imre; Busse, Matthias

    2012-08-01

    Zinc oxide particles with different morphologies were prepared by hydrothermal method at 60-90 °C. The structure formation was controlled by the addition rate and temperature of hydrolyzing agent, while the particles size (10 nm-2.5 μm) was influenced by the preparation (hydrothermal) temperature. Scanning electron microscopy studies showed that raspberry-, prism- and flower-like ZnO particles were prepared, whose average size decreased with increasing reaction temperature. X-ray diffraction investigations confirmed that ZnO particles with hexagonal crystal structure formed in all syntheses. The raspberry-, prism- and flower-like ZnO particles showed a weak UV-emission in the range of 390-395 nm and strong visible emission with a maximum at 586, 593 and 598 nm, respectively. Morphology effect on electrical and water vapour sensing properties of ZnO samples was investigated by impedance spectroscopy and quartz crystal microbalance, respectively. The absolute impedance of raspberry-, prism- and flower-like ZnO particles was found to be strong dependent on the morphology. Space-charge-limited conductivity transport mechanism was proved by the oscillatory behaviour of impedance. Humidity sensor tests also revealed morphology and specific surface area dependency on the sensitivity and water vapour adsorption property.

  16. Growth of raspberry-, prism- and flower-like ZnO particles using template-free low-temperature hydrothermal method and their application as humidity sensors

    Energy Technology Data Exchange (ETDEWEB)

    Pal, Edit, E-mail: edit.pal@uni-bremen.de [University of Bremen, Faculty of Production Engineering, FB 4, Near Net Shape Technologies (Germany); Hornok, Viktoria [Supramolecular and Nanostructured Materials Research Group of the Hungarian Academy of Sciences (Hungary); Kun, Robert; Chernyshev, Vladimir [University of Bremen, Faculty of Production Engineering, FB 4, Near Net Shape Technologies (Germany); Seemann, Torben [Fraunhofer Institute for Manufacturing Technology and Advanced Materials Research (IFAM) (Germany); Dekany, Imre [Supramolecular and Nanostructured Materials Research Group of the Hungarian Academy of Sciences (Hungary); Busse, Matthias [University of Bremen, Faculty of Production Engineering, FB 4, Near Net Shape Technologies (Germany)

    2012-08-15

    Zinc oxide particles with different morphologies were prepared by hydrothermal method at 60-90 Degree-Sign C. The structure formation was controlled by the addition rate and temperature of hydrolyzing agent, while the particles size (10 nm-2.5 {mu}m) was influenced by the preparation (hydrothermal) temperature. Scanning electron microscopy studies showed that raspberry-, prism- and flower-like ZnO particles were prepared, whose average size decreased with increasing reaction temperature. X-ray diffraction investigations confirmed that ZnO particles with hexagonal crystal structure formed in all syntheses. The raspberry-, prism- and flower-like ZnO particles showed a weak UV-emission in the range of 390-395 nm and strong visible emission with a maximum at 586, 593 and 598 nm, respectively. Morphology effect on electrical and water vapour sensing properties of ZnO samples was investigated by impedance spectroscopy and quartz crystal microbalance, respectively. The absolute impedance of raspberry-, prism- and flower-like ZnO particles was found to be strong dependent on the morphology. Space-charge-limited conductivity transport mechanism was proved by the oscillatory behaviour of impedance. Humidity sensor tests also revealed morphology and specific surface area dependency on the sensitivity and water vapour adsorption property.

  17. Influence of Li doping on the optical and magnetic properties of ZnO nanorods synthesized by low temperature hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Kung, C.Y., E-mail: cykung@dragon.nchu.edu.tw [Department of Electrical Engineering, National Chung Hsing University, Taichung 40227, Taiwan (China); Lin, C.C. [Department of Electrical Engineering, National Chung Hsing University, Taichung 40227, Taiwan (China); Young, S.L., E-mail: slyoung@mail.hust.edu.tw [Department of Electronic Engineering, Hsiuping University of Science and Technology, Taichung 41280, Taiwan (China); Horng, Lance; Shih, Y.T. [Department of Physics, National Changhua University of Education, Changhua 50007, Taiwan (China); Kao, M.C.; Chen, H.Z. [Department of Electronic Engineering, Hsiuping University of Science and Technology, Taichung 41280, Taiwan (China); Lin, H.H. [Department and Graduate School of Electrical Engineering, Hsiuping University of Science and Technology, Taichung 41280, Taiwan (China); Lin, J.H.; Wang, S.J.; Li, J.M. [Department of Electronic Engineering, Hsiuping University of Science and Technology, Taichung 41280, Taiwan (China)

    2013-02-01

    Well-defined pure Zn{sub 1−x}Li{sub x}O (x = 0, 0.05 and 0.1) nanorods were hydrothermally synthesized at the low temperature of 90 °C. The X-ray diffraction patterns of all three compositions with a single diffraction peak (0002) showed the same wurtzite hexagonal structure due to the similar radius of Zn and Li. The optical and magnetic properties were influenced by the oxygen vacancies induced by Li doping in the ZnO nanorods. The Raman shift spectrum indicated a slight increasement of oxygen vacancies which enhanced the green emission and ferromagnetism by the doping of Li in the ZnO nanorods. Besides, p-type ZnO:Li semiconductor nanorods were obtained by Li doping. The characteristics of the UV photodetector with p-ZnO:Li nanorod/n-Si structure were also measured. - Highlights: ► Zn{sub 1−x}Li{sub x}O nanorods have grown by hydrothermal method at a low temperature of 90 °C. ► Doping of Li increases the doping-induced defects. ► Saturation magnetization increases as Li content increases. ► ZnO-based UV photodetector with nanorod structure is achieved.

  18. An Integrated Intuitionistic Fuzzy Multi Criteria Decision Making Method for Facility Location Selection

    OpenAIRE

    BORAN, Fatih

    2011-01-01

    The facility location selection, which is one of the important activities in strategic planning for a wide range of private and public companies, is a multi-criteria decision making problem including both quantitative and qualitative criteria. Traditional methods for facility location selection can not be effectively handled because information can not be represented by precise information under many conditions. This paper proposes the integration of intuitionistic fuzzy preference relation a...

  19. Facile stamp patterning method for superhydrophilic/superhydrophobic surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Lyu, Sungnam, E-mail: blueden@postech.ac.kr; Hwang, Woonbong, E-mail: whwang@postech.ac.kr [Department of Mechanical Engineering, POSTECH, Pohang 680-749 (Korea, Republic of)

    2015-11-16

    Patterning techniques are essential to many research fields such as chemistry, biology, medicine, and micro-electromechanical systems. In this letter, we report a simple, fast, and low-cost superhydrophobic patterning method using a superhydrophilic template. The technique is based on the contact stamping of the surface during hydrophobic dip coating. Surface characteristics were measured using scanning electron microscopy and energy-dispersive X-ray spectroscopic analysis. The results showed that the hydrophilic template, which was contacted with the stamp, was not affected by the hydrophobic solution. The resolution study was conducted using a stripe shaped stamp. The patterned line was linearly proportional to the width of the stamp line with a constant narrowing effect. A surface with regions of four different types of wetting was fabricated to demonstrate the patterning performance.

  20. A facile method to modify bentonite nanoclay with silane

    Science.gov (United States)

    Abeywardena, Sujani B. Y.; Perera, Srimala; Nalin de Silva, K. M.; Tissera, Nadeeka P.

    2017-07-01

    Immobilization of smectite clay onto a desirable surface has received much attention, since its nanospace can be utilized for many applications in material science. Here, we present an efficient method to functionalize surface of bentonite nanoclay (BNC) through the grafting of 3-aminotriethoxysilane (APTES). Infrared spectroscopy and elemental analysis confirmed the presence of organic chains and amine groups in modified nanoclay. XRD analysis confirmed grafting of APTES on the surface of bentonite nanoclay without intercalation. The accomplishment of the surface modification was quantitatively proved by TGA analysis. Modified BNC can covalently couple with different material surfaces, allowing its nanospace to be utilized for intercalation of cations, bio-molecules, and polymeric materials, to be used in advanced military aerospace, pharmaceuticals, and many other commercial applications.

  1. A facile method for imparting superoleophobicity to polymer substrates

    Science.gov (United States)

    Ren, Guina; Zhang, Zhaozhu; Zhu, Xiaotao; Ge, Bo; Wang, Kun; Xu, Xianghui; Men, Xuehu; Zhou, Xiaoyan

    2014-03-01

    A new method was presented to impart polymer substrate with superoleophobic properties. Aluminum/polymer composite was created by a hot-pressing process, and rough surface textures needed to establish superoleophobicity were created by HCl etching and boiling water treatment. After surface fluorination, the surface became super-repellent towards water and several organic liquids, such as hexadecane. The effect of geometrical structure on hydrophobicity and oleophobicity was investigated, and the result showed that the synergistic action of microterraces and nanoflakes played a key role in establishing oleophobicity. A waterfall/jet test demonstrated that the obtained surface can keep its superoleophobicity after a long time exposure to water. Moreover, the obtained surface did not lose the superoleophobicity after placing it under cold condition for 7 days.

  2. The role of Mg dopant on the morphological, structural and optical properties of Mg doped zinc oxide grown through hydrothermal method

    Science.gov (United States)

    Susetyo, P.; Fauzia, V.; Sugihartono, I.

    2017-04-01

    ZnO nanorods is a low cost II-VI semiconductor compound with huge potential to be applied in optoelectronic devices i.e. light emitting diodes, solar cells, gas sensor, spintronic devices and lasers. In order to improve the electrical and optical properties, group II, III and IV elements were widely investigated as dopand elements on ZnO. In this work, magnesium (Mg) was doped into ZnO nanorods. Samples were prepared firstly by deposition of undoped ZnO seed layer on indium thin oxide coated glass substrates by ultrasonic spray pyrolysis method and then followed by the growth of ZnO nanorods doped by three different Mg concentrations by hydrothermal method. Based on the morphological, microstructural and optical characterizations results, it is concluded that the increase of magnesium concentration tends to reduce the diameter of ZnO nanorods, increases the bandgap energy and decreases the UV absorption the luminescence in UV and visible range.

  3. 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.

  4. BCT phase formation in synthesis via microwave assisted hydrothermal method; Limite da concentracao de Ca na formacao da fase BCT em sintese via metodo hidrotermico assistido por microondas

    Energy Technology Data Exchange (ETDEWEB)

    Barra, B.C.; Souza, A.E.; Teixeira, S.R.; Santos, G.T.A.; Lanzi, C.A.C. [Universidade Estadual Paulista Julio de Mesquita Filho (FCT/DFQB/UNESP), Presidente Prudente, SP (Brazil). Fac. de Ciencia e Tecnologia. Dept. de Fisica, Quimica e Biologia; Longo, E. [Universidade Estadual Paulista Julio de Mesquita Filho (IQ/UNESP/), Araraquara, SP (Brazil); Instituto Nacional de Ciencias e Tecnologia de Materiais em Nanotecnologia (INCTMN), Araraquara, SP (Brazil)

    2012-07-01

    In previous work, samples of barium and calcium titanate (Ba1-xCaxTiO3 (BCT x = 0- 1) were prepared using the microwave assisted hydrothermal method in conditions of relatively short time and temperature. To the sample with 75wt% of Ca no BCT phase was formed but the photoluminescent emission was improved. In the present study, these titanates were synthesized by the same method with other concentrations of Ca, Ba1-xCaxTiO3 (x = 0, 0.20, 0.40, 0. 60, 0.80 and 1) to evaluate the limit of BCT phase formation. Results of X-ray diffraction showed that the phase BCT is formed between zero and 50wt%-Ca, in Ba substitution. Above this concentration, was observed only the formation of carbonates, and to x = 1 there was carbonate formation together with CaTiO3. These results were confirmed by micro Raman spectroscopy. (author)

  5. 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.

  6. 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.

  7. Enhanced visible-light-responsive photodegradation of bisphenol A by Cu, N-codoped titanate nanotubes prepared by microwave-assisted hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Doong, Ruey-an, E-mail: radoong@nctu.edu.tw [Institute of Environmental Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan (China); Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Liao, Chun-Yi [Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

    2017-01-15

    Highlights: • The Cu, N-codoped TNTs were prepared by microwave assisted hydrothermal method. • The Cu(0) in codoped TNTs can serve as electron donors as well as electron meditors. • The surface normalized rate constants for BPA removal by Cu, N-TNT were 1.5–4.3 times higher than that of P25 TiO{sub 2}. • The Cu, N-codoped TNTs prolonged the generation of radicals for at least 5 min. - Abstract: In this study, a rapid and effective microwave-assisted hydrothermal method was developed for the synthesis of Cu, N-codoped titanate nanotubes (Cu, N-TNTs) to enhance the photocatalytic degradation efficiency and rate of bisphenol A (BPA) under UV and visible light irradiations. The TNTs were first synthesized at 150 °C for 3 h under microwave heating conditions followed by the calcination at 450 °C in the presence of 6 wt% Cu ions and N{sub 2}/NH{sub 3} to fabricate Cu, N-TNTs composites. The Cu, N-TNTs exhibited excellent photocatalytic activity toward BPA degradation under UV and visible light irradiations. The X-ray photoelectron spectra indicated that Cu species in Cu, N-TNTs were mainly in zerovalent form and could serve as the electron donors as well as shuttling species to accelerate the photodegradation of BPA. In addition, the nitrogen atoms were incorporated into the anatase lattices to increase the visible-light-responsive capability. The surface normalized reaction rate constants for BPA degradation were 4.3 and 1.5 times higher than those of Degussa P25 TiO{sub 2} under UV and visible light irradiations, respectively. The electron spin resonance spectra showed that Cu, N-codoped TNTs prolonged the generation of oxygen-containing radicals for at least 5 min, resulting in the significant enhancement of photodegradation efficiency and rate of BPA. Results obtained in this study open a new avenue by using simple and effective microwave-assisted hydrothermal method to fabricate low dimensional codoped TNTs which can be potentially applied in a wide

  8. Enhancement of zinc vacancies in room-temperature ferromagnetic Cr–Mn codoped ZnO nanorods synthesized by hydrothermal method under high pulsed magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Min [Laboratory for Microstructures/School of Materials Science and Engineering, Shanghai University, 149 Yanchang Road, 200072 Shanghai (China); Li, Ying, E-mail: liying62@shu.edu.cn [Laboratory for Microstructures/School of Materials Science and Engineering, Shanghai University, 149 Yanchang Road, 200072 Shanghai (China); Hu, Yemin; Zhu, Mingyuan; Li, Wenxian; Jin, Hongmin; Wang, Shiwei [Laboratory for Microstructures/School of Materials Science and Engineering, Shanghai University, 149 Yanchang Road, 200072 Shanghai (China); Li, Yibing; Zhao, Huijun [Centre for Clean Environment and Energy, Griffith School of Environment, Griffith University, Gold Coast Campus, QLD 4222 (Australia)

    2015-10-25

    Room-temperature ferromagnetic Cr–Mn codoped ZnO diluted magnetic semiconductor was synthesized by pulse magnetic field-assisted hydrothermal method. X-ray diffraction and Raman spectra analysis reveal that all the samples have hexagonal wurtzite structure. High resolution transmission electron microscopy and Energy-dispersive spectroscopy measurements ensure that the Cr and Mn ions are incorporated into the wurtzite host matrix without any detectable impurity phase. X-ray photoelectron spectroscopy confirms that Mn and Cr ions are doped into the ZnO wurtzite host matrix with divalent states in the sample without magnetic field processing. Cr ions became trivalent states in ZnO synthesized with high pulsed magnetic field, while Mn keeps its divalent state. The presence of Cr{sup 3+} is attributed to hole doping in ZnO with zinc vacancies induced by the field. Magnetization measurements reveal the appearance of ferromagnetism for the magnetic field processed sample. Comparing with oxygen vacancies, zinc vacancies (hole doping) is more effectively to stabilized ferromagnetism in Mn-doped ZnO diluted magnetic semiconductors. - Graphical abstract: This figure shows the magnetization versus magnetic field curves for ZnO–Cr–Mn-0T and ZnO–Cr–Mn-4T at 290 K. The 4 T sample was well-defined hysteresis loops, which is indicative of room-temperature ferromagnetic behavior. But for 0 T sample, no ferromagnetic response at 290 K is observed. The hole doping enhanced by high pulsed magnetic field is crucial to stabilize ferromagnetism in Mn-doped ZnO diluted magnetic semiconductor. And the presence of Cr{sup 3+} in 4 T sample is a possible signature of hole doping induced by zinc vacancies. - Highlights: • Cr–Mn codoped ZnO nanorods were synthesized by hydrothermal method. • High pulsed magnetic field was applied during the hydrothermal method. • The valence state of doped elements was investigated by XPS. • High pulsed magnetic field enhances the

  9. Hydrothermal precipitation of artificial violarite

    DEFF Research Database (Denmark)

    Jørgensen, W. H.; Toftlund, H.; Warner, T. E.

    2012-01-01

    The nonstoichiometric nickel-ore mineral, violarite, (Ni,Fe)3S4 was prepared as a phase-pure fine powder by a comparatively quick hydrothermal method from an aqueous solution of iron(II) acetate, nickel(II) acetate and DL-penicillamine in an autoclave at 130 °C for 45 h. Powder-XRD showed...

  10. Hydrothermal precipitation of artificial violarite

    DEFF Research Database (Denmark)

    Jørgensen, W. H.; Toftlund, H.; Warner, T. E.

    2012-01-01

    The nonstoichiometric nickel-ore mineral, violarite, (Ni,Fe)3S4 was prepared as a phase-pure fine powder by a comparatively quick hydrothermal method from an aqueous solution of iron(II) acetate, nickel(II) acetate and DL-penicillamine in an autoclave at 130 °C for 45 h. Powder-XRD showed that th...

  11. Synthesis of uniform and size-controllable carbon nanospheres by a simple hydrothermal method and fabrication of carbon nanosphere super-hydrophobic surface

    Energy Technology Data Exchange (ETDEWEB)

    Joula, Mohsen Heidari; Farbod, Mansoor, E-mail: farbod_m@scu.ac.ir

    2015-08-30

    Highlights: • A simple hydrothermal method was used to produce carbon nanospheres (CNSs). • The size of CNSs was controlled by the concentration of initial sucrose solution. • The size of CNSs was reduced to 100 nm by post-annealing of the CNSs. • A glass substrate was coated with CNSs thick film using spin coating method. • Contact angle of a water droplet was 153° indicating the film is super-hydrophobic. - Abstract: A simple hydrothermal method was used to produce high yield, monodisperse and tightly controllable size of carbon nanospheres (CNSs) by adjusting the concentration of initial sucrose solution in a sealed autoclave at 170 °C for 8 h. By changing the solution concentration from 0.5 to 0.1 mol l{sup −1}, the sizes of carbon spheres (CS) were reduced from about 2500 to about 300 nm. Also by increasing the solution volume to the vessel volume ratio (V{sub s}/V{sub v}) from 5/6 to 11/13, the yield of CS was increased from 25% up to about 55% of initial raw materials. It was found that by post-annealing of the 300 nm CNSs at 435 °C for 30 min, their diameters were reduced to 100 nm. Moreover, annealing in air atmosphere had a noticeable influence on the surface functional groups and bonds of CNSs. In addition, CNSs were used to fabricate hydrophobic surfaces by coating their ethanolic colloidal solution on glass substrates. The measured contact angle (CA) of a water droplet was about 153°, indicating that the CNSs thick layers were super-hydrophobic. The size dependence of CNSs on the different parameters has been discussed.

  12. Methods of sampling airborne fungi in working environments of waste treatment facilities

    Directory of Open Access Journals (Sweden)

    Kristýna Černá

    2016-06-01

    Full Text Available Objectives: The objective of the present study was to evaluate and compare the efficiency of a filter based sampling method and a high volume sampling method for sampling airborne culturable fungi present in waste sorting facilities. Material and Methods: Membrane filters method was compared with surface air system method. The selected sampling methods were modified and tested in 2 plastic waste sorting facilities. Results: The total number of colony-forming units (CFU/m3 of airborne fungi was dependent on the type of sampling device, on the time of sampling, which was carried out every hour from the beginning of the work shift, and on the type of cultivation medium (p < 0.001. Detected concentrations of airborne fungi ranged 2×102–1.7×106 CFU/m3 when using the membrane filters (MF method, and 3×102–6.4×104 CFU/m3 when using the surface air system (SAS method. Conclusions: Both methods showed comparable sensitivity to the fluctuations of the concentrations of airborne fungi during the work shifts. The SAS method is adequate for a fast indicative determination of concentration of airborne fungi. The MF method is suitable for thorough assessment of working environment contamination by airborne fungi. Therefore we recommend the MF method for the implementation of a uniform standard methodology of airborne fungi sampling in working environments of waste treatment facilities.

  13. Microwave-assisted Facile and Ultrafast Growth of ZnO Nanostructures and Proposition of Alternative Microwave-assisted Methods to Address Growth Stoppage

    Science.gov (United States)

    Rana, Abu Ul Hassan Sarwar; Kang, Mingi; Kim, Hyun-Seok

    2016-04-01

    The time constraint in the growth of ZnO nanostructures when using a hydrothermal method is of paramount importance in contemporary research, where a long fabrication time rots the very essence of the research on ZnO nanostructures. In this study, we present the facile and ultrafast growth of ZnO nanostructures in a domestic microwave oven within a pressurized environment in just a few minutes. This method is preferred for the conventional solution-based method because of the ultrafast supersaturation of zinc salts and the fabrication of high-quality nanostructures. The study of the effect of seed layer density, growth time, and the solution’s molar concentration on the morphology, alignment, density, and aspect ratio of ZnO nanorods (ZNRs) is explored. It is found in a microwave-assisted direct growth method that ~5 mins is the optimum time beyond which homogeneous nucleation supersedes heterogeneous nucleation, which results in the growth stoppage of ZNRs. To deal with this issue, we propound different methods such as microwave-assisted solution-replacement, preheating, and PEI-based growth methods, where growth stoppage is addressed and ZNRs with a high aspect ratio can be grown. Furthermore, high-quality ZnO nanoflowers and ZnO nanowalls are fabricated via ammonium hydroxide treatment in a very short time.

  14. Study on the Influencing Factors of Preparing Bismuth-doped Zinc Oxide Nano-powders by Hydrothermal Method%水热法制备纳米铋掺杂氧化锌的影响因素研究

    Institute of Scientific and Technical Information of China (English)

    乐小芳; 谭艳; 陈燕梅; 万谦; 马粉波; 吕维忠

    2012-01-01

    以氯化锌、硝酸铋为主要原料,氢氧化钠为沉淀剂,采用水热法制备了纳米铋掺杂氧化锌粉体。研究了pH值对产物成分的影响,分析了水热时间和水热温度对产物形貌的影响。结果表明pH为9,水热温度为240℃,水热时间为25 h时可以得到微观形貌良好的纳米铋掺杂氧化锌粉体。%Bismuth-doped zinc oxide(BZO) nano-particles were prepared by hydrothermal method using ZnCl2 and Bi(NO3)3·5H2O as precursors and NaOH as precipitant.The effects of hydrothermal temperature,hydrothermal time,and pH value were mainly studied.The results showed that hydrothermal time of 25 h,hydrothermal temperature of 240 ℃ and terminal pH of 7 can produce bismuth doped zinc oxide as nearly as expected.

  15. Structure and optical properties of pure and Eu3+ doped SrTiO3 by the polymeric precursor and hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Silva, M.G.N.; Gasparotto, G.; Cebim, M. A.; Zaghete, M.A.; Varela, J.A. [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Araraquara, SP (Brazil). Instituto de Quimica

    2009-07-01

    Full text: SrTiO3 (ST) has a simple cubic perovskite structure and is a semiconductor with an indirect band gap usually ranging from 3.2 to 3.4 eV. By modifying ST structurally, this material can be made to show a variety of physical properties. In this work, we report the preparation and characterization of pure and europium(III)-doped SrTiO3 obtained via the polymeric precursor and hydrothermal method. Samples were prepared containing different quantities of Eu3{sup +} ions in order to evaluate their effect on the structure property of the material. The analysis of X-ray diffraction results indicated that it was possible to obtain the SrTiO3 phase at 190 deg C free of secondary phases. We have also analyzed the powders by diffuse reflectance spectroscopy and evaluated the bandgap of the compounds using the Kubelka-Munk approximation. (author)

  16. One-step mild hydrothermal method to prepare low valent sodium vanadium(III) monohydrogenphosphate: NaV(HPO4)2

    Science.gov (United States)

    Abeysinghe, Dileka; Smith, Mark D.; zur Loye, Hans-Conrad

    2017-07-01

    Green colored single crystals of a reduced sodium vanadium(III) monohydrogenphosphate, NaV(HPO4)2, were grown using a one-step mild hydrothermal method. The in situ reduction of V5+ to V3+ was performed using copper acetate as the reducing agent. The title compound crystalizes in the monoclinic space group Cc and exhibits a three-dimensional crystal structure that consists of distorted VO6 octahedra connected to PO3(OH) tetrahedra that are further connected via Na cations. The compound exhibits simple paramagnetic behavior at high temperatures and a discontinuity near 5 K is likely due to the onset of magnetic coupling. The compound was also characterized by TGA, IR and UV-vis spectroscopies.

  17. 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.

  18. Synthesis of morphology-controlled ZnO microstructures via a microwave-assisted hydrothermal method and their gas-sensing property.

    Science.gov (United States)

    Liang, Sa; Zhu, Lianfeng; Gai, Guosheng; Yao, Youwei; Huang, Jue; Ji, Xuewen; Zhou, Xiaoming; Zhang, Dongyun; Zhang, Peixin

    2014-07-01

    Controllable ZnO architectures with flower-like and rod-like morphologies were synthesized via a microwave-assisted hydrothermal method. By adjusting the concentration of Zn(2+) in the aqueous precursors, different morphologies of ZnO microstructures were obtained. The size of ZnO was uniform after ultrasonic treatment. The growth process of ZnO in solution was studied by monitoring the intermediate products, which were extracted at different stages of the reactions: (i) precursor preparation, (ii) microwave irradiation heating, (iii) natural cooling. Studies of the SEM images and XRD data revealed that the formation of ZnO occurred via in situ assembly or dissolution-reprecipitation of zinc hydroxide complexes. The morphology-dependent ethanol sensing performance was observed; the seven-spine ZnO structures exhibit the highest activity.

  19. Structural, morphological and magnetic properties of Zn1-x Co x O prepared by sol—gel and hydrothermal method combined

    Science.gov (United States)

    Yongde, Hao; Legui, Zhou; Jun, Li; Zuoqi, Hu

    2016-11-01

    Cobalt-doped ZnO powder samples were prepared by sol—gel and hydrothermal method combined. The prepared powder samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), electron paramagnetic resonance (EPR) and vibrating sample magnetometry (VSM). XRD patterns show that all the samples have a single pure phase with wurtzite structure suggesting that Co2+ occupied Zn2+ sites in the ZnO crystal lattice. SEM images show that crystal grains of cobalt-doped ZnO are hexagonal cone or spheroidal. EPR pattern shows that all of the samples possess oxygen vacancy. Measurement of magnetism indicates that all the samples exhibit room temperature ferromagnetism (RTFM) embedded in a dominant diamagnetic or paramagnetic signal. The dominant signal turns from diamagnetic to paramagnetic with the increase of Co concentration. The magnetic behavior can attribute to defects and Co doping. Project supported by the 46th Institute of China Electronics Technology Group Corporation (No. 0231182346).

  20. Synthesis and Characterization of SnO2-TiO2 Nanocomposite with Rutile-phase via Hydrothermal Method at Low Temperature

    Institute of Scientific and Technical Information of China (English)

    WANG Yuan-rui; LI Wen-yan; ZHOU Bing; ZHAO Xu

    2013-01-01

    With Ti(SO4)2,SnCl4·5H2O and urea as raw materials,SnO2-TiO2 nanocomposites were synthesized via low temperature hydrothermal method at 80-100 ℃ in aqueous solutions.The morphologies of the products were altered systematically by varying the Ti/Sn molar ratio of the reactants,and rutile-phase particles were obtained with an average diameter of about 52.2 nm at a molar ratio of Ti/Sn=7.5.The surface composition of the composite was revealed by X-ray photoelectron spectroscopy(XPS) and X-ray diffraction(XRD) to be solely TiO2 with a rutile structure.This new composite material exhibits a high ultraviolet absorption capacity,and its photocatalytic activity for phenol oxidation is much lower than that of the commercial titania nanoparticles(P25).

  1. A Simple and Efficient Method for Synthesizing Te Nanowires from CdTe Nanoparticles with EDTA as Shape Controller under Hydrothermal Condition

    Directory of Open Access Journals (Sweden)

    Fangfang Xue

    2012-01-01

    Full Text Available We developed a simple and efficient method for synthesizing Te nanowires from CdTe nanoparticles with ethylenediaminetetraacetic acid disodium salt dehydrate (EDTA as shape controller under hydrothermal condition. The system could both complete the transformation to Te and reduce the interference of CdTeS by adjusting the concentration of EDTA, which was proved by inductively coupled plasma mass spectrometry, X-ray diffraction patterns, and Raman spectra. It was found that the as-prepared Te nanowires display strong fluorescence emission in the blue-violet region. The nanowires exhibit a pretty good morphology with the average diameter of ca. 30 nm and a length up to micrometer scale. Moreover, a possible transformation mechanism of CdTe nanoparticles into Te nanowires is also discussed.

  2. The Effect of Sodium Dodecyl Sulfate (SDS and Cetyltrimethylammonium Bromide (CTAB on the Properties of ZnO Synthesized by Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Yun Hin Taufiq-Yap

    2012-10-01

    Full Text Available ZnO nanostructures were synthesized by hydrothermal method using different molar ratios of cetyltrimethylammonium bromide (CTAB and Sodium dodecyl sulfate (SDS as structure directing agents. The effect of surfactants on the morphology of the ZnO crystals was investigated by field emission scanning electron microscopy (FESEM and transmission electron microscopy (TEM techniques. The results indicate that the mixture of cationic-anionic surfactants can significantly modify the shape and size of ZnO particles. Various structures such as flakes, sheets, rods, spheres, flowers and triangular-like particles sized from micro to nano were obtained. In order to examine the possible changes in other properties of ZnO, characterizations like powder X-ray diffraction (PXRD, thermogravimetric and differential thermogravimetric analysis (TGA-DTG, FTIR, surface area and porosity and UV-visible spectroscopy analysis were also studied and discussed.

  3. Ionic Liquid-Assisted Hydrothermal Method Synthesis of Flower-Like MoS2 and Their Electrochemical Performances.

    Science.gov (United States)

    Li, Maohua; Yang, Bo; Hao, Junying; Lu, Yi; Long, Zerong; Liu, Yumei

    2016-06-01

    Molybdenum disulfide (MoS2) was prepared successfully via hydrothermal reaction at 200 degrees C in water/ethanol (1:1) solvent system using the ammonium molybdate and sodium thiosulfate as the molybdenum sources and sulfur sources, 1-butyl-3-methylimidazolium chloride salt [BMIM][Cl] as the additive agent. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to examine the morphology and structure of flower-like products. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy spectrum analysis results show that the as-prepared product is a pure phase of MoS2. The prepared products are used as electrode materials for Li-ion batteries and showed excellent cycle stability and high Coulombic efficiency at a current density of 200 mA x g(-1) in the voltage range of 0.01 - 3.00 V (vs. Li/Li+). In addition, this paper also examined the influence of the reaction time and the amount of template agent on morphology, and discussed the reaction mechanism of the formation of flower-like morphology.

  4. Morphology and phase transformations of tin oxide nanostructures synthesized by the hydrothermal method in the presence of dicarboxylic acids

    Science.gov (United States)

    Zima, Tatyana.; Bataev, Ivan

    2016-11-01

    A new approach to the synthesis of non-stoichiometric tin oxide structures with different morphologies and the phase compositions has been evaluated. The nanostructures were synthesized by hydrothermal treatment of the mixtures of dicarboxylic acids ― aminoterephthalic or oxalic ― with nanocrystalline SnO2 powder, which was obtained via the sol-gel technology. The products were characterized by Raman and IR spectroscopy, SEM, HRTEM, and XRD analysis. It was shown that the controlled addition of a dicarboxylic acid leads not only to a change in the morphology of the nanostructures, but also to SnO2-SnO2/Sn3O4-Sn3O4-SnO phase transformations. A single-phase Sn3O4 in the form of the well-separated hexagonal nanoplates and mixed SnO2/Sn3O4 phases in the form of hierarchical flower-like structures were obtained in the presence of organic additives. The effects of concentration, redox activity of the acids and heat treatment on the basic characteristics of the synthesized tin oxide nanostructures and phase transformations in the synthesized materials are discussed.

  5. Methods of sampling airborne fungi in working environments of waste treatment facilities.

    Science.gov (United States)

    Černá, Kristýna; Wittlingerová, Zdeňka; Zimová, Magdaléna; Janovský, Zdeněk

    2016-01-01

    The objective of the present study was to evaluate and compare the efficiency of a filter based sampling method and a high volume sampling method for sampling airborne culturable fungi present in waste sorting facilities. Membrane filters method was compared with surface air system method. The selected sampling methods were modified and tested in 2 plastic waste sorting facilities. The total number of colony-forming units (CFU)/m3 of airborne fungi was dependent on the type of sampling device, on the time of sampling, which was carried out every hour from the beginning of the work shift, and on the type of cultivation medium (p method, and 3×102-6.4×104 CFU/m3 when using the surface air system (SAS) method. Both methods showed comparable sensitivity to the fluctuations of the concentrations of airborne fungi during the work shifts. The SAS method is adequate for a fast indicative determination of concentration of airborne fungi. The MF method is suitable for thorough assessment of working environment contamination by airborne fungi. Therefore we recommend the MF method for the implementation of a uniform standard methodology of airborne fungi sampling in working environments of waste treatment facilities. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

  6. Fabrication of Li{sub 2}TiO{sub 3} pebbles with small grain size via hydrothermal and improved dry-rolling methods

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wen; Zhou, Qilai; Xue, Lihong, E-mail: xuelh@mail.hust.edu.cn; Yan, Youwei

    2015-09-15

    Highlights: • The fabricated pebbles can be densified (81% T.D.) at a low sintering temperature (850 °C). • The pebbles’ size can be controlled during the fabrication process. • Average grain size of the Li{sub 2}TiO{sub 3} pebbles is less than 1 μm (0.82 μm). • The molar ratio of Li to Ti of the pebbles sintered at 850 °C keeps the value of 1.97 after sintering. - Abstract: Lithium titanate (Li{sub 2}TiO{sub 3}) ceramic pebbles were successfully fabricated by using hydrothermal and improved dry-rolling method. In the present work, ultra-fine Li{sub 2}TiO{sub 3} powder of high reactivity was prepared via hydrothermal reaction, using anatase titania and lithium hydroxide as raw materials. The as-synthesized Li{sub 2}TiO{sub 3} powder exhibits an average crystalline size as small as 100 nm. Improved dry-rolling method was employed to fabricate Li{sub 2}TiO{sub 3} pebbles. The green pebbles can be well-sintered (81% T.D.) at a temperature as low as 850 °C for 3 h. The pebbles have good sphericity (1.08) and narrow diameter distribution (1.0–1.2 mm) with a crush load of 35 N. Scanning electron microscope (SEM) observations of pebbles showed that the ceramic grain size was below 1 μm and atomic emission spectrometer fitted with inductively coupled plasma (ICP-AES) results confirmed that atomic ratio of Li to Ti in the fabricated pebbles was 1.97.

  7. In situ deposition of graphene nanosheets on wood surface by one-pot hydrothermal method for enhanced UV-resistant ability

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Caichao, E-mail: wancaichaojy@163.com; Jiao, Yue, E-mail: yjiao123@126.com; Li, Jian, E-mail: lijiangroup@tom.com

    2015-08-30

    Graphical abstract: - Highlights: • The graphene/wood nanocomposites were fabricated via a mild fast one-pot hydrothermal method. • Graphene nanosheets were in situ deposited on the surface of the wood matrix. • The incorporation of graphene nanosheets results in the improvement in the thermal stability of the graphene/wood. • The graphene/wood exhibits superior UV resistance performance. - Abstract: Graphene nanosheets were successfully in situ deposited on the surface of the wood matrix via a mild fast one-pot hydrothermal method, and the resulting hybrid graphene/wood (GW) were characterized by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Raman spectroscopy, and thermogravimetric analysis (TGA). According to the results, the wood matrix was evenly coated by dense uninterrupted multilayer graphene membrane structure, which was formed by layer-by-layer self-assembly of graphene nanosheets. Meanwhile, the graphene coating also induced significant improvement in the thermal stability of GW in comparison with that of the original wood (OW). Accelerated weathering tests were employed to measure and determine the UV-resistant ability of OW and GW. After about six hundred hours of experiments, the surface color change of GW was much less than that of OW; besides, the Fourier transform infrared spectroscopy (FTIR) analysis also proved the less significant changes in surface chemical compositions of GW. The results both indicated that the graphene coating effectively protected wood surface from UV damage. Therefore, this class of GW composite might be expected to be served as high-performance wooden building material for outdoor or some particular harsh environments like strong UV radiation regions use.

  8. LiFePO4 Nanostructures Fabricated from Iron(III) Phosphate (FePO4 x 2H2O) by Hydrothermal Method.

    Science.gov (United States)

    Saji, Viswanathan S; Song, Hyun-Kon

    2015-01-01

    Electrode materials having nanometer scale dimensions are expected to have property enhancements due to enhanced surface area and mass/charge transport kinetics. This is particularly relevant to intrinsically low electronically conductive materials such as lithium iron phosphate (LiFePO4), which is of recent research interest as a high performance intercalation electrode material for Li-ion batteries. Many of the reported works on LiFePO4 synthesis are unattractive either due to the high cost of raw materials or due to the complex synthesis technique. In this direction, synthesis of LiFePO4 directly from inexpensive FePO4 shows promise.The present study reports LiFePO4 nanostructures prepared from iron (III) phosphate (FePO4 x 2H2O) by precipitation-hydrothermal method. The sintered powder was characterized by X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), Inductive coupled plasma-optical emission spectroscopy (ICP-OES), and Electron microscopy (SEM and TEM). Two synthesis methods, viz. bulk synthesis and anodized aluminum oxide (AAO) template-assisted synthesis are reported. By bulk synthesis, micro-sized particles having peculiar surface nanostructuring were formed at precipitation pH of 6.0 to 7.5 whereas typical nanosized LiFePO4 resulted at pH ≥ 8.0. An in-situ precipitation strategy inside the pores of AAO utilizing the spin coating was utilized for the AAO-template-assisted synthesis. The template with pores filled with the precipitate was subsequently subjected to hydrothermal process and high temperature sintering to fabricate compact rod-like structures.

  9. 水热法制备高纯超细CeO2-ZrO2复合氧化物%Preparation of High Purity and Superfine CeO2-ZrO2 by Hydrothermal Method

    Institute of Scientific and Technical Information of China (English)

    郑育英; 黄慧民; 邓淑华; 李大光; 余双平

    2005-01-01

    Superfine composite powders of CeO2-ZrO2 (CZ) and CeO2-ZrO2-La2O3 (CZL) were prepared by hydrothermal method. The effects of pH ,temperature and time for hydrothermal process on the performance of the resulting powders were studied. The optimized reaction parameters were on follows: the precursor's pH≈9.0, hydrothermal temperature of 200 ℃ holding for 2 h. Thermal stable powders with average particle size smaller than 10 nm and specific surface area of 171 m2·g-1 were obtained. A BET specific surface area was still at 44 m2·g-1 after calcination at 1 000 ℃ for 6 hours.

  10. Validation of cleaning method for various parts fabricated at a Beryllium facility

    Energy Technology Data Exchange (ETDEWEB)

    Davis, Cynthia M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-12-15

    This study evaluated and documented a cleaning process that is used to clean parts that are fabricated at a beryllium facility at Los Alamos National Laboratory. The purpose of evaluating this cleaning process was to validate and approve it for future use to assure beryllium surface levels are below the Department of Energy’s release limits without the need to sample all parts leaving the facility. Inhaling or coming in contact with beryllium can cause an immune response that can result in an individual becoming sensitized to beryllium, which can then lead to a disease of the lungs called chronic beryllium disease, and possibly lung cancer. Thirty aluminum and thirty stainless steel parts were fabricated on a lathe in the beryllium facility, as well as thirty-two beryllium parts, for the purpose of testing a parts cleaning method that involved the use of ultrasonic cleaners. A cleaning method was created, documented, validated, and approved, to reduce beryllium contamination.

  11. Electricity generation from hydrothermal vents

    Science.gov (United States)

    Aryadi, Y.; Rizal, I. S.; Fadhli, M. N.

    2016-09-01

    Hydrothermal vent is a kind of manifestation of geothermal energy on seabed. It produces high temperature fluid through a hole which has a diameter in various range between several inches to tens of meters. Hydrothermal vent is mostly found over ocean ridges. There are some 67000 km of ocean ridges, 13000 of them have been already studied discovering more than 280 sites with geothermal vents. Some of them have a thermal power of up to 60 MWt. These big potential resources of energy, which are located over subsea, have a constraint related to environmental impact to the biotas live around when it becomes an object of exploitation. Organic Rankine Cycle (ORC) is a method of exploiting heat energy to become electricity using organic fluid. This paper presents a model of exploitation technology of hydrothermal vent using ORC method. With conservative calculation, it can give result of 15 MWe by exploiting a middle range diameter of hydrothermal vent in deep of 2000 meters below sea level. The technology provided here really has small impact to the environment. With an output energy as huge as mentioned before, the price of constructing this technology is low considering the empty of cost for drilling as what it should be in conventional exploitation. This paper also presents the comparison in several equipment which is more suitable to be installed over subsea.

  12. Improved Electrochemical Performance of Orthorhombic LiMn1-xCrxO2 Synthesized by Hydrothermal Method

    Institute of Scientific and Technical Information of China (English)

    Xiaoyan TU; Guanglie LU; Yuewu ZENG

    2006-01-01

    Single phase chromium-substituted orthorhombic LiMn1-xCrxO2 (0≤x≤0.05) were successfully synthesized by hydrothermal treatment of Mn2O3, Cr2O3 and lithium hydroxide aqueous solution. Structure and morphologies of the o-LiMn1-xCrxO2 were characterized by X-ray diffraction and transmission electron microscopy.Compared to the particle size of o-LiMnO2 ranging from 50 to 150 nm, the Cr-doped one is larger with about 500 nm, which is agglomerated by small grains. There are high stacking faults in nanosized grains that cause easier phase transformation from the orthorhombic to the spinel-like structure on cycling. High-resolution transmission electron microscopy image analysis of electrochemically cycled o-LiMn1-xCrxO2 (x=0, 0.05)samples showed that the nanodomain structure in o-LiMn0.95Cr0.05O2 was comparatively perfect to that in o-LiMnO2. Particle agglomeration and the relatively perfect crystal structure are two key factors for improving cycle performance of o-LiMn0.95Cr0.05O2. The obtained o-LiMn0.95Cr0.05O2 can reach a maximum discharge capacity of 174 mA·h·g-1 at 0.1 C rate in seventh cycle. The discharge capacity fade rate of the samples decreased with increasing Cr amount. Furthermore, o-LiMn0.95Cr0.05O2 gives a highest discharge capacity of 150 mA·h·g-1 at a high current rate of 0.5 C, and retains 130 mA·h·g-1 after 40 cycles.

  13. [REDUCTION OF THE CONTENT OF AFLATOXIN-FORMING FUNGI IN CONTAMINATED GRAINS BY METHODS OF HYDROTHERMAL TREATMENT].

    Science.gov (United States)

    Shentsova, E S; Lytkina, L I; Shevtsov, A A

    2015-01-01

    Microscopic fungi affecting grain and products of its processing, under certain conditions, are capable of producing over 100 mycotoxins, some of which are carcinogenic. Mycotoxins are falled to the most dangerous contaminants of food and compound animal feedstuff, they possess toxicity, mutagenic and carcinogenic properties. The most toxic and dangerous carcinogens are aflatoxins which affect on virtually all cells of the body of the human and agricultural animals, provoking the occurrence of diseases--aflatoxicoses. Aflatoxins give rise to encephalopathy and fatty degeneration of internal organs. The World Health Organization mentions aflatoxins as a cause of the origin of cancer. Currently in Russia there is a real danger of the negative impact of mycotoxins on farm animals in feeding grain affected by aflatoxins. The gain in the number of aflatoxicoses is a serious hygienic problem. This is related with the wide spread of producers of aflatoxins in nature and also with the intensive trade of grain and products of its processing between countries, a lack of control over their content. Detoxification of the affected products is an actual task, because its use causes irreparable harm to human health andfarm animals. Currently there are known several ways of inactivation of aflatoxins in the grain, based on the use of hydrothermal treatment. IR heat treatment, ultraviolet irradiation and extrusion were established to be the most rational approaches, providing the reduction offungi in the grain of aflatoxin-forming fungi by 80 ... 100%, aflatoxin B1--by the 76... 100% and a decrease in the degree of toxicity by 2.3 times. There are presented experimental data of various ways of disinfecting grain and appropriateness of their application in practice.

  14. Low-Temperature NH3–SCR of NO on Mesoporous Mn0.6Fe0.4/TiO2 Prepared by a Hydrothermal Method

    DEFF Research Database (Denmark)

    Schill, Leonhard; Putluru, Siva Sankar Reddy; Fehrmann, Rasmus

    2014-01-01

    Mesoporous 30 wt% Mn0.6Fe0.4/TiO2 has been prepared by a novel hydrothermal method using a structure directing agent and characterized by N2 adsorption, SEM, XRD, EDX, H2-TPR and the catalytic activity for the selective catalytic reduction (SCR) of NO by ammonia was measured under power plant flu...

  15. Ionic liquid-based hydrothermal synthesis of Lu2O3 and Lu2O3:Eu3+ microcrysals

    Science.gov (United States)

    Li, Yinyan; Xu, Shiqing

    2016-09-01

    Uniform and well-defined Lu2O3 and Lu2O3:Eu3+ microarchitectures have been successfully synthesized via a green and facile ionic liquid-based hydrothermal method followed by a subsequent calcination process. Novel 3D micro-rodbundles and 1D microrods of Lu2O3 and Lu2O3:Eu3+ were controllably obtained through this method. X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy and photoluminescence spectra were used to characterize the micromaterials. The proposed formation mechanisms have been investigated on the basis of a series of SEM studies of the products obtained at different hydrothermal durations. The results indicated that hydrothermal temperature and the ionic liquid-tetrabutylammonium hydroxide were two key factors for the formation as well as the morphology control of the Lu2O3 and Lu2O3:Eu3+ microarchitectures.

  16. Preventing introduction and spread of Dermanyssus gallinae in poultry facilities using the HACCP method

    NARCIS (Netherlands)

    Mul, M.F.; Koenraadt, C.J.M.

    2009-01-01

    Preventing the establishment of ectoparasitic poultry red mite (Dermanyssus gallinae) populations is key in ensuring welfare and egg production of laying hens and absence of allergic reactions of workers in poultry facilities. Using the Hazard Analysis and Critical Control Point method, a panel of e

  17. Lidar Based Emissions Measurement at the Whole Facility Scale: Method and Error Analysis

    Science.gov (United States)

    Particulate emissions from agricultural sources vary from dust created by operations and animal movement to the fine secondary particulates generated from ammonia and other emitted gases. The development of reliable facility emission data using point sampling methods designed to characterize regiona...

  18. A cross-monotonic cost sharing method for the facility location game with service installation costs

    Institute of Scientific and Technical Information of China (English)

    XU DaChuan

    2009-01-01

    In this paper, we consider the metric uncapacitated facility location game with service installation costs. Our main result is an 11-approximate cross-monotonic cost-sharing method under the assumption that the installation cost depends only on the service type.

  19. A cross-monotonic cost sharing method for the facility location game with service installation costs

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    In this paper,we consider the metric uncapacitated facility location game with service installation costs. Our main result is an 11-approximate cross-monotonic cost-sharing method under the assumption that the installation cost depends only on the service type.

  20. 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.

  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. Preventing introduction and spread of Dermanyssus gallinae in poultry facilities using the HACCP method.

    Science.gov (United States)

    Mul, Monique F; Koenraadt, Constantianus J M

    2009-06-01

    Preventing the establishment of ectoparasitic poultry red mite (Dermanyssus gallinae) populations is key in ensuring welfare and egg production of laying hens and absence of allergic reactions of workers in poultry facilities. Using the Hazard Analysis and Critical Control Point method, a panel of experts identified hazards and associated risks concerning the introduction and spread of this mite in poultry facilities. Together we provide an overview of possible corrective actions that can be taken to prevent population establishment. Additionally, a checklist of the most critical control points has been devised as management tool for poultry farmers. This list was evaluated by Dutch and British poultry farmers. They found the checklist feasible and useful.

  3. Measurements of methane emissions from natural gas gathering facilities and processing plants: measurement methods

    Directory of Open Access Journals (Sweden)

    J. R. Roscioli

    2014-12-01

    Full Text Available Increased natural gas production in recent years has spurred intense interest in methane (CH4 emissions associated with its production, gathering, processing, transmission and distribution. Gathering and processing facilities (G&P facilities are unique in that the wide range of gas sources (shale, coal-bed, tight gas, conventional, etc. results in a wide range of gas compositions, which in turn requires an array of technologies to prepare the gas for pipeline transmission and distribution. We present an overview and detailed description of the measurement method and analysis approach used during a 20-week field campaign studying CH4 emissions from the natural gas G&P facilities between October 2013 and April 2014. Dual tracer flux measurements and onsite observations were used to address the magnitude and origins of CH4 emissions from these facilities. The use of a second tracer as an internal standard revealed plume-specific uncertainties in the measured emission rates of 20–47%, depending upon plume classification. Combining downwind methane, ethane (C2H6, carbon monoxide (CO, carbon dioxide (CO2, and tracer gas measurements with onsite tracer gas release allows for quantification of facility emissions, and in some cases a more detailed picture of source locations.

  4. Thermochemical parameters of minerals from oxygen-buffered hydrothermal equilibrium data: Method, application to annite and almandine

    Science.gov (United States)

    Zen, E.-A.

    1973-01-01

    Reversed univariant hydrothermal phase-equilibrium reactions, in which a redox reaction occurs and is controlled by oxygen buffers, can be used to extract thermochemical data on minerals. The dominant gaseous species present, even for relatively oxidizing buffers such as the QFM buffer, are H2O and H2; the main problem is to calculate the chemical potentials of these components in a binary mixture. The mixing of these two species in the gas phase was assumed by Eugster and Wones (1962) to be ideal; this assumption allows calculation of the chemical potentials of the two components in a binary gas mixture, using data in the literature. A simple-mixture model of nonideal mixing, such as that proposed by Shaw (1967), can also be combined with the equations of state for oxygen buffers to permit derivation of the chemical potentials of the two components. The two mixing models yield closely comparable results for the more oxidizing buffers such as the QFM buffer. For reducing buffers such as IQF, the nonideal-mixing correction can be significant and the Shaw model is better. The procedure of calculation of mineralogical thermochemical data, in reactions where hydrogen and H2O simultaneously appear, is applied to the experimental data on annite, given by Wones et al. (1971), and on almandine, given by Hsu (1968). For annite the results are: Standard entropy of formation from the elements, Sf0 (298, 1)=-283.35??2.2 gb/gf, S0 (298, 1) =+92.5 gb/gf. Gf0 (298, 1)=-1148.2??6 kcal, and Hf0 (298, 1)=-1232.7??7 kcal. For almandine, the calculation takes into account the mutual solution of FeAl2O4 (Hc) in magnetite and of Fe3O4 (Mt) in hercynite and the temperature dependence of this solid solution, as given by Turnock and Eugster (1962); the calculations assume a regular-solution model for this binary spinel system. The standard entropy of formation of almandine, Sf,A0 (298, 1) is -272.33??3 gb/gf. The third law entropy, S0 (298, 1) is +68.3??3 gb/gf, a value much less than the

  5. Bi2Fe4O9 Nanoparticles: Preparation by Hydrothermal Method and Characterization%Bi2Fe4O9纳米粉体:水热法制备及表征

    Institute of Scientific and Technical Information of China (English)

    于志伟; 苗鸿雁; 谈国强

    2008-01-01

    Bi2Fe4O9 nanoparticles were prepared at low temperature via a facile, one-step hydrothermal synthesis starting materials and sodium hydroxide (NaOH) as the precipitant and mineralizer. XRD results indicate that the as-prepared nanoparticles are pure Bi2Fe4O9. SEM images reveal that the as-prepared Bi2Fe4O9 nanoparticles have a sheet-like morphology. The Bi2Fe5O9 nanoparticles thus obtained are paramagnetic at room temperature as shown by magnetic measurements.

  6. A facile hydrothermal recovery of nano sealed MnO2 particle from waste batteries: An advanced material for electrochemical and environmental applications

    Science.gov (United States)

    Mylarappa, M.; Venkata Lakshmi, V.; Vishnu Mahesh, K. R.; Nagaswarupa, H. P.; Raghavendra, N.

    2016-09-01

    This work deliberates a method for manganese (Mn) recovery as manganese oxide obtained by leaching of waste batteries with 3M sulphuric acid. The Experimental test for the recovery of Mn present within the waste dry cell batteries were carried out by a reductive leachant. Elemental composition of leached sample was confirmed by Energy Dispersive X-ray analysis (EDAX), and Surface morphology of the recovered MnO2 was examined by using Scanning Electron microscopy (SEM). Phase composition was confirmed from X-ray Diffractro meter (XRD). The obtained leached solution was treated with 4M NaOH, yielded to Manganese Dioxide with high extraction degree, while it do not touches the Zn content within the solutions. The recovered samples were characterized using XRD, EDAX, SEM and Fourier transform infrared spectrometry (FTIR). The electrochemical properties of the as-recovered sample from leached solution was examined used cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Remarkably, the 80 wt.% MnO2 displays reversibility, diffusion constant, smaller equivalent series resistance and charge transfer resistance in 0.5M NaOH showed superior results as compared to alternative electrolytes. The ideal capacitive behaviour of MnO2 electrode and nano particle was applied to photocatalytic degradation of dyes.

  7. 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.

  8. Ag{sub 2}O/Ag{sub 3}VO{sub 4}/Ag{sub 4}V{sub 2}O{sub 7} heterogeneous photocatalyst prepared by a facile hydrothermal synthesis with enhanced photocatalytic performance under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ran, Rong; McEvoy, Joanne Gamage [Department of Chemical and Biological Engineering, University of Ottawa, Ottawa, Ontario, K1N 6N5 (Canada); Centre for Catalysis Research and Innovation, University of Ottawa, Ottawa, Ontario, K1N 6N5 (Canada); Zhang, Zisheng, E-mail: zzhang@uottawa.ca [Department of Chemical and Biological Engineering, University of Ottawa, Ottawa, Ontario, K1N 6N5 (Canada); Centre for Catalysis Research and Innovation, University of Ottawa, Ottawa, Ontario, K1N 6N5 (Canada)

    2016-02-15

    Highlights: • The photocatalyst was hydrothermally prepared by adjusting the ratio of Ag to V. • Multi-phase Ag{sub 2}O/Ag{sub 3}VO{sub 4}/Ag{sub 4}V{sub 2}O{sub 7} obtained exhibited multi-morphological features. • The photocatalyst exhibited strong visible light driven photoactivity towards RhB. - Abstract: A novel Ag{sub 2}O/Ag{sub 3}VO{sub 4}/Ag{sub 4}V{sub 2}O{sub 7} photocatalyst was synthesized by adjusting the molar ratio of silver–vanadium (Ag–V) in a facile hydrothermal method to obtain multi-phase Ag{sub 2}O/Ag{sub 3}VO{sub 4}/Ag{sub 4}V{sub 2}O{sub 7} photocatalyst. The photocatalytic activity of the prepared samples was quantified by the degradation of Rhodamine B (RhB) model organic pollutant under visible light irradiation. Compared to pure Ag{sub 3}VO{sub 4}, Ag{sub 4}V{sub 2}O{sub 7} and P25 TiO{sub 2}, respectively, the as-synthesized multi-phase Ag{sub 2}O/Ag{sub 3}VO{sub 4}/Ag{sub 4}V{sub 2}O{sub 7} powders gave rise to a significantly higher photocatalytic activity, achieving up to 99% degradation of RhB in 2 h under visible light. This enhanced photocatalytic performance was attributed to the effect of the multi-phase Ag{sub 2}O/Ag{sub 3}VO{sub 4}/Ag{sub 4}V{sub 2}O{sub 7} photocatalyst and the surface plasmon resonance (SPR) of the incorporated metallic silver (Ag{sup 0}) nanoparticles (NPs) generated during the photocatalysis, as evidenced by post-use characterization, resulting in improved visible light absorption and electron-hole (e{sup −}-h{sup +}) separation. A mechanism was proposed for the photocatalytic degradation of RhB on the surface of Ag{sub 2}O/Ag{sub 3}VO{sub 4}/Ag{sub 4}V{sub 2}O{sub 7}.

  9. Photocatalytic hydrogen generation over porous ZnIn{sub 2}S{sub 4} microspheres synthesized via a CPBr-assisted hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Xuefeng, E-mail: bxuefeng@163.net [Institute of Petrochemistry, Heilongjiang Academy of Sciences, Harbin 150040 (China); School of Chemistry and Materials, Heilongjiang University, Harbin 150070 (China); Li, Jinshu [School of Chemistry and Materials, Heilongjiang University, Harbin 150070 (China)

    2011-07-15

    Graphical abstract: ZnIn{sub 2}S{sub 4} porous microspheres were synthesized via a cetylpyridinium bromide (CPBr)-assisted hydrothermal method. It could be seen from the SEM image that the flowerlike microspheres were composed of numerous nanosheets. Many slit-like pores were formed among the curved nanosheets. The porous structure benefited the adsorption of reactants, the diffuseness of products, the charge separation on surface, the transfer of the interfacial charge carriers and the charge carrier trapping. And porous ZnIn{sub 2}S{sub 4} photocatalyst exhibited higher photocatalytic activity than nonporous ZnIn{sub 2}S{sub 4} material. Highlights: {yields} A series of unique flower-like porous ZnIn{sub 2}S{sub 4} microspheres of hexagonal crystal phase as efficient visible-light photocatalysts have been synthesized through CPBr-assisted hydrothermal method. {yields} The CPBr addition would visibly influence the self-assemble growing and the crystal structure including the position and intensity of some peaks. {yields} We also found that the pH value plays a crucial role in the formation of ZnIn{sub 2}S{sub 4} porous microspheres and the influence of the pH on the structure of product has been first reported in our paper. {yields} The results showed that our as-synthesized porous ZnIn{sub 2}S{sub 4} microspheres possessed a specific surface area of 165.4 m{sup 2} g{sup -1} and performed higher visible-light photocatalytic activity than bulk ZnIn{sub 2}S{sub 4} for hydrogen evolution. The maximum H{sub 2} evolution rate of ZnIn{sub 2}S{sub 4} reaches 1544.8 {mu}mol/(h g). -- Abstract: Hexagonal ZnIn{sub 2}S{sub 4} porous microspheres were synthesized via a cetylpyridinium bromide (CPBr)-assisted hydrothermal method. The structure, morphology and optical property of these prepared products were characterized by wide angle X-ray diffraction (WAXRD), small angle X-ray diffraction (SAXRD), UV-Vis diffusive reflectance spectroscopy (DRS), field emission scanning

  10. 微波水热法制备CdS纳米晶体的研究%Semiconductor Nanocrystals CdS Synthesized by Microwave-Hydrothermal Method

    Institute of Scientific and Technical Information of China (English)

    王悦虹; 刘岩

    2012-01-01

    利用微波水热技术合成CdS半导体纳米晶体,可以克服有机合成方法毒性大,成本高等问题,通过XRD、TEM表征,产物CdS半导体纳米晶体具有立方晶相,纯度较高。通过紫外吸收光谱和荧光光谱分析,发现该方法制备出的半导体CdS纳米晶体具有良好的光致发光性质,证明水相同样适合高质量CdS半导体纳米晶体的生长。%CdS semiconductor nanocrystals(NCs) were synthesized by microwave-hydrothermal method in water solution.In comparison,with the synthesis of NCs in organic solvents,the growth surroundings of aqueous NCs were more poisonous and costly.The XRD and TEM provided direct evidence for a cubic zinc blende structure of bulk CdS crystal.Moreover,the CdS NCs had excellent photoluminescence properties by the characterizations of absorption spectra and luminescence spectra.This method proved that CdS NCs suited to grow in aqueous condition.

  11. Structural studies of BaTiO3:Er3+and BaTiO3:Yb3+powders synthesized by hydrothermal method

    Institute of Scientific and Technical Information of China (English)

    Garrido-Hernndez A; Garca-Murillo A; Carrillo-Romo Fde J; Cruz-Santiago LA; Chadeyron G; Morales-Ramrez Ade J; Velumani S

    2014-01-01

    Erbium and ytterbium doped barium titanate nanopowders were prepared using the hydrothermal method. A barium titan-ate structure doped with rare earth ions manifested new characteristics and improved the field of application of optical devices such as trichromatic tubes, LCD displays, lamps, and infrared lasers. In this work, BaTiO3:Er3+and BaTiO3:Yb3+were prepared using barium chloride [BaCl2], titanium butoxide [C16H36O4Ti], erbium chloride [ErCl3] and ytterbium chloride [YbCl3] as precursors. Anhydrous methanol was employed as a solvent. Metallic potassium was used to promote solubility in the system and increase the pH to 13. This method yielded the formation of a predominantly cubic structure in both Er3+and Yb3+doped BaTiO3 powders. Characteristic bond-ings of BaTiO3 were observed with FT-IR spectroscopy. The predominantly cubic structure was confirmed by X-ray diffraction and micro-Raman analyses. The particle size (∼30 nm) was estimated using the Scherrer equation and X-ray diffraction data. The results were presented and discussed.

  12. Facile and green synthesis of (La0.95Eu0.052O2S red phosphors with sulfate-ion pillared layered hydroxides as a new type of precursor: controlled hydrothermal processing, phase evolution and photoluminescence

    Directory of Open Access Journals (Sweden)

    Xuejiao Wang

    2014-01-01

    Full Text Available This study presents a facile and green route for the synthesis of (La0.95Eu0.052O2S red phosphors of controllable morphologies, with the sulfate-type layered hydroxides of Ln2(OH4SO4centerdot2H2O (Ln = La and Eu as a new type of precursor. The technique takes advantage of the fact that the precursor has had the exact Ln:S molar ratio of the targeted phosphor, thus saving the hazardous sulfurization reagents indispensable to traditional synthesis. Controlled hydrothermal processing at 120 °C yielded phase-pure Ln2(OH4SO4centerdot2H2O crystallites in the form of either nanoplates or microprisms, which can both be converted into Ln2O2S phosphor via a Ln2O2SO4 intermediate upon annealing in flowing H2 at a minimum temperature of ~ 700 °C. The nanoplates collapse into relatively rounded Ln2O2S particles while the microprisms retain well their initial morphologies at 1 200 °C, thus yielding two types of red phosphors. Photoluminescence excitation (PLE studies found two distinct charge transfer (CT excitation bands of O2− → Eu3+ at ~ 270 nm and S2− → Eu3+ at ~ 340 nm for the Ln2O2S phosphors, with the latter being stronger and both significantly stronger than the intrinsic intra-f transitions of Eu3+. The two types of phosphors share high similarities in the positions of PLE/PL (photoluminescence bands and both show the strongest red emission at 627 nm (5D0 → 7F2 transition of Eu3+ under S2− → Eu3+ CT excitation at 340 nm. The PLE/PL intensities show clear dependence on particle morphology and calcination temperature, which were investigated in detail. Fluorescence decay analysis reveals that the 627 nm red emission has a lifetime of ~ 0.5 ms for both types of the phosphors.

  13. Applications versus properties of Mg–Al layered double hydroxides provided by their syntheses methods: Alkoxide and alkoxide-free sol–gel syntheses and hydrothermal precipitation

    KAUST Repository

    Chubar, Natalia

    2013-12-01

    A tremendous number of studies have examined layered double hydroxides (LDH) for their technological applications in the ion exchange removal of toxic ions, recovery of valuable substances, catalysis, CO2 capture, as a layered host for storage/delivery of biologically active molecules, additives to plastics and building materials, and other functions. Numerous publications always conclude that the materials (prepared, as a rule, using the oldest synthesis method) are very promising for each investigated application; however, the main chemical industries producing these materials advertise them mainly (or only) as plastic additives. The authors performed extensive research using many of the appropriate methods to compare the structure, surface and adsorptive properties of three Mg-Al LHDs produced by advanced synthesis methods. One industrial sample (by Sasol, Germany) prepared by the alkoxide sol-gel method and two novel Mg-Al LDHs synthesised in-house by alkoxide-free sol-gel and hydrothermal precipitation approaches were investigated. Reasons for the very different adsorptive selectivity of the three LDHs towards arsenate, selenate, phosphate, arsenite and selenite have been provided, highlighting the role of speciation of the interlayer carbonate, aluminium, magnesium, interlayer hydration and moisture content in the adsorptive selectivity towards each toxic anion. This work is the first report presenting the regularities of the LDHs structure, surface and anion exchange properties as a function of their syntheses method. It establishes the links to potential technological applications of each investigated LDH and explains the necessary properties required to make the technological application cost-effective and efficient. The paper might accelerate industrial applications of these advanced materials. © 2013 Elsevier B.V.

  14. Effect of nickel salt precursors on morphology, size, optical property and type of products (NiSe or Se) in hydrothermal method

    Science.gov (United States)

    Salavati-Niasari, Masoud; Sobhani, Azam

    2013-03-01

    NiSe micro/nanocrystals with multiform morphologies, including particles, rods and flowers were prepared by hydrothermal method from different Ni salts: NiBr2, Ni(ClO4)2ṡ6H2O, NiCl2ṡ6H2O and NiSO4ṡ6H2O. Se nanorods were produced simply by varying the nickel salts to Ni(CH3COO)2ṡH2O and Ni(NO3)2ṡ6H2O. The process was performed at 180 °C for 12 h and cetyltrimethyl ammonium bromide (CTAB) and hydrazine hydrate (N2H4ṡH2O) used as surfactant and reductant, respectively. The samples were analyzed by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electronic diffraction (SAED) and X-ray energy dispersive spectroscopy (EDS). The synthesis was performed conveniently and safely.

  15. 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)

  16. Effect of calcination temperatures on the electrochemical performances of nickel oxide/reduction graphene oxide (NiO/RGO) composites synthesized by hydrothermal method

    Science.gov (United States)

    Chen, Gang; Guan, Hongtao; Dong, Chengjun; Xiao, Xuechun; Wang, Yude

    2016-11-01

    A series of NiO/RGO composites based on NiO nanoparticles anchored on layered RGO surfaces were proposed by the same hydrothermal method combined with different calcination temperatures (250, 300, 400 and 500 °C). The effects of calcination temperatures on the capacitive behaviors have been discussed by investigating the components, morphologies, surface conditions of the NiO/RGO composites. The specific capacitance values of NiO/RGO composites calcined at 250, 300, 400 and 500 °C are 950, 553, 375 and 205 F/g at the current density of 1 A/g and the corresponding capacitance retention are 91.3%, 83.9%, 71.9% and 67.3% after 1000 cycles at the current density of 10 A/g. The results suggest the calcination temperature plays an important role in the electrochemical performances of NiO/RGO composites and the electrochemical performances were deteriorated with the increasing calcination temperatures.

  17. Synthesis and Characterization of Pyrochlore Bi2Sn2O7 Doping with Praseodymium by Hydrothermal Method and Its Photocatalytic Activity Study

    Directory of Open Access Journals (Sweden)

    Weicheng Xu

    2013-01-01

    Full Text Available Praseodymium doped Bi2Sn2O7 (BSO, as a visible-light responsive photocatalyst, was prepared by a hydrothermal method with different dopant contents. The as-prepared photocatalysts were investigated by X-ray diffraction (XRD, scanning electron microscope (SEM, transmission electron microscope (TEM, N2 adsorption-desorption isotherm, X-ray photoelectron spectroscopy analysis (XPS, and UV-Vis diffuse reflectance spectroscopy (DRS. The photocatalytic activity of prepared catalysts was evaluated by the degradation of Rhodamine Bextra (RhB and 2,4-dichlorophenol (2,4-DCP in aqueous solution under visible light irradiation. It was found that Pr doping inhibited the growth of crystalline size and the as-prepared materials were small in size (10–20 nm. In our experiments, Pr-doped BSO samples exhibited enhanced visible-light photocatalytic activity compared to the undoped BSO, and the optimal dopant amount of Pr was 1.0 mol% for the best photocatalytic activity. On the basis of the calculated PL spectra, the mechanism of enhanced photocatalytic activity has been discussed.

  18. Vacancy-induced room-temperature ferromagnetism in ZnO rods synthesized by Ni-doped solution and hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Yu Zhenhua [Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou 730000 (China); Ge Shihui, E-mail: gesh@lzu.edu.cn [Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou 730000 (China); Zuo Yalu; Wang Guowei; Zhang Feng [Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou 730000 (China)

    2010-08-01

    Pure ZnO and Ni-doped ZnO rods have been prepared by hydrothermal method at a temperature of 120 deg. C. The morphological, structural, magnetic and optical properties of the as-prepared rods were investigated by means of field emission scanning electron microscopy, X-ray diffraction, vibrating sample magnetometer and photoluminescence. All the samples are radial-grown hexagon rods with diameter from 470 to 720 nm and length of 4-6 {mu}m. X-ray diffraction shows that the rods have single crystalline wurtzite structure without other impurity phases. The pure ZnO rods and Ni-doped ZnO rods have ferromagnetism at room temperature, and the special saturation magnetization deduces with the increasing diameter of rods. These results reveal that the saturation magnetization of the ZnO rods depends on the surface-to-volume ratio of rods rather than the Ni doping concentrations. The photoluminescence spectra studies show the same diameter dependences of oxygen vacancies as that of magnetization, which demonstrates that oxygen vacancies at surface of rods play an important role in introducing ferromagnetism. The annealing in rich oxygen and reducing atmospheres confirms this argument further.

  19. Effects of post-heated ZnO seed layers on structural and optical properties of ZnO nanostructures grown by hydrothermal method

    Science.gov (United States)

    Kim, Soaram; Nam, Giwoong; Yim, Kwang Gug; Lee, Jewon; Kim, Yangsoo; Leem, Jae-Young

    2013-05-01

    ZnO nanostructures were grown by the hydrothermal method on ZnO seed layers post-heated in the range 350°C-500°C. The effects of the post-heated ZnO seed layers on the structural and optical properties of the ZnO nanostructures were investigated by scanning electron microscopy (SEM), x-ray diffraction (XRD) spectroscopy, and photoluminescence (PL) spectroscopy. The average grain sizes in the ZnO seed layers increased with increasing post-heating temperature, and nano-fibrous structures were observed on the surface of the ZnO seed layers post-heated at 450°C. The ZnO seed layers post-heated in the range 350°C-500°C affected the residual stress, lattice distortion in the ZnO nanostructures and the intensity, positions, and full widths at half maximum of 2 θ and PL peaks in the XRD and PL spectra for the ZnO nanostructures.

  20. Magnetic Properties of Co0.5Zn0.5Fe2O4 Nanoparticles Synthesized by a Template-Assisted Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    H. Y. He

    2011-01-01

    Full Text Available In the present paper, nickel cobalt ferrite (Co0.5Zn0.5Fe2O4 nanoparticles were synthesized using a template-assisted hydrothermal method. Carboxymethyl cellulose was used as the templating agent for controlling the morphology of the Co0.5Zn0.5Fe2O4 nanoparticles. The synthesized nanoparticles were characterized using X-ray diffraction, scanning electron microscopy, and a vibrating sample magnetometer. The results indicated that the morphology of the nanoparticles changed from granular and superparamagnetic to platelike and ferromagnetic with the addition of the template. The Co0.5Zn0.5Fe2O4 nanoparticles synthesized without the template exhibited a saturation magnetization and coercivity 2.81 T and 0.2 kA⋅m−1, while when the template was used, the saturation magnetization and coercivity increased to 3.13 T and 76.6 kA⋅m−1 as the template proportion increased to 0.3.

  1. Structure and photoluminescence properties of Ce0.5Zr0.5O2:Eu3+ nanoparticles synthesized by hydrothermal method

    Science.gov (United States)

    Ozawa, Masakuni; Yoshimura, Yusuke; Kobayashi, Katsutoshi

    2017-01-01

    Eu3+-doped Ce0.5Zr0.5O2 nanocrystals were prepared by a hydrothermal method. The structural and optical properties of the samples were characterized by X-ray diffraction, Raman scattering and photoluminescence spectra. No luminescence was observed for Ce0.5Zr0.5O2, while Ce0.5Zr0.5O2:Eu3+ nanoparticles as-prepared and calcined at 400 °C showed emission due to Eu3+. The emission spectrum of the Eu3+ site shows that the total intensity decreases with increasing concentration of Eu3+ from 1 to 10% in Ce0.5Zr0.5O2. The broad band in the excitation spectrum of calcined Ce0.5Zr0.5O2:Eu3+ originates from the charge transfer (CT) transition. The local distortion and the asymmetry factor around the Eu3+ centers were discussed with the Raman and photoluminescence spectra. The present study provides both knowledge expected to lead to novel nanocrystal phosphor materials and a useful measure for analyzing the catalytic properties of nanocrystalline Ce0.5Zr0.5O2.

  2. The Preparation of Porous Sol-Gel Silica with Metal Organic Framework MIL-101(Cr) by Microwave-Assisted Hydrothermal Method for Adsorption Chillers

    Science.gov (United States)

    Uma, Kasimayan; Pan, Guan-Ting; Yang, Thomas C.-K.

    2017-01-01

    Metal organic framework (MOF) of MIL-101(Cr)-Silica (SiO2) composites with highly mesoporous and uniform dispersions were synthesized by a microwave-assisted hydrothermal method followed by the sol-gel technique. Water vapor adsorption experiments were conducted on the MIL-101(Cr)-SiO2 composites for industrial adsorption chiller applications. The effects of MIL-101(Cr)-SiO2 mixing ratios (ranging from 0% to 52%), the surface area and amount of Lewis and Brønsted sites were comprehensively determined through water vapor adsorption experiments and the adsorption mechanism is also explained. The BET and Langmuir results indicate that the adsorption isotherms associated with the various MIL-101(Cr)-SiO2 ratios demonstrated Type I and IV adsorption behavior, due to the mesoporous structure of the MIL-101(Cr)-SiO2. It was observed that the increase in the amount of Lewis and Brønsted sites on the MIL-101(Cr)-SiO2 composites significantly improves the water vapor adsorption efficiency, for greater stability during the water vapor adsorption experiments. PMID:28772969

  3. Effect of HNO3 Concentration on the Morphologies and Properties of Bi2WO6 Photocatalyst Synthesized by a Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Wenjie Wang

    2016-07-01

    Full Text Available Bi2WO6 samples were prepared by a hydrothermal method using Bi(NO33·5H2O and Na2WO4·2H2O as raw materials. X-ray diffraction (XRD, field-emission scanning electron microscopy (FESEM, Raman and Brunauer–Emmett–Teller (BET were employed for sample characterization. The photocatalytic activity of the samples was evaluated by the degradation of Rhodamine B under visible-light irradiation. The photocatalytic activity of Bi2WO6, as well as the effect of varying HNO3 concentrations on the morphologies of Bi2WO6, was investigated. The HNO3 concentration significantly affected the structure and morphology of the Bi2WO6. The photocatalytic performance varied with the structure, morphology, and surface area of the Bi2WO6 samples. The results indicated that the H10 sample exhibits uniform morphology and excellent photocatalytic performance; using this sample, the degradation of Rhodamine B reached 96% in 90 min under visible-light irradiation.

  4. PREPARATION OF BaF2 POWDERS BY HYDROTHERMAL METHOD%水热法制备BaF2粉体材料

    Institute of Scientific and Technical Information of China (English)

    李红; 赵星

    2012-01-01

    以销酸钡和氟化铵为原料,以柠檬酸为络合剂,采用水热法合成了BaF2粉体。用扫描电子显微镜(SEM)和X射线衍射仪(XRD)对产物的形貌和结构进行了表征,结果表明反应温度及pH值对产物的形状和尺寸有很大影响,可以通过改变温度和pH值调控产物的形貌。%BaF2 powders were synthesized by hydrothermal methods. For this preparation, Ba(NO3)2 and NH4F as the starting materials and citric acid served as chelator. The morphology and the structure was characterized by scanning electron microscopy (SEM) and X-ray diffraction. The results show that the temperature and pH value of the reaction have significant effects on the particle size and shape. The morphology could be controlled synthesized by the temperature and pH value.

  5. Synthesis of LiFePO4/Li2SiO3/reduced Graphene Oxide (rGO) Composite via Hydrothermal Method

    Science.gov (United States)

    Arifin, M.; Iskandar, F.; Aimon, A. H.; Munir, M. M.; Nuryadin, B. W.

    2016-08-01

    LiFePO4 is a type of cathode active material used for lithium ion batteries. It has a high electrochemical performance. However, it suffers from certain disadvantages such as a very low intrinsic electronic conductivity and low ionic diffusion. This study was conducted to increase the conductivity of LiFePO4. We have investigated the addition of Li2SiO3 and reduced graphene oxide (rGO) to LiFePO4. The objective of this research was to synthesize LiFePO4/Li2SiO3/rGO via hydrothermal method. Fourier transform infrared spectroscopy (FTIR) measurement showed that the peaks corresponded to the vibration of LiFePO4/Li2SiO3. Further, X-ray diffraction (XRD) measurement confirmed a single phase of LiFePO4. Finally, scanning electron microscopy (SEM) images showed that rGO was distributed on the LiFePO4/Li2SiO3 structure.

  6. Structure and photoluminescence properties of fishbone-like PbMoO4 nanostructures obtained via the surfactant-assisted hydrothermal method

    Institute of Scientific and Technical Information of China (English)

    Runping Jia; Kangsheng Zheng

    2012-01-01

    Fishbone-like PbMoO4 nanostructures are successfully obtained via the surfactant-assisted hydrothermal method at 160 ℃.Polyethylene glycol (PEG2000) is used as the template agent.The nanostructures are characterized via X-ray diffraction,field-emission scanning electron microscopy,Fourier transform infrared spectroscopy,ultraviolet-visible light (UV-Vis) spectroscopy,and photoluminescence (PL) measurements.The PbMoO4 morphology is highly associated with the molecular nature of PEG2000.PbMoO4 nanoparticles obtained from PEG2000 have a fishbone-shaped,scheelite-type tetragonal structure,in which numerous secondary branches vertically grow on both sides of the main stem.The structures exhibit broad PL emission bands with the maximum at 306 and 390 nm when excited at 250 nm.In addition,the UV-Vis absorption edge of the structures is in the 280 to 310 nm region,and the band gap is 4.07 eV.A plausible formation mechanism for the fishbone-like PbMoO4 nanostructures is also discussed.

  7. One-pot synthesis of carbon-coated SnO2 nano-composite using hydrothermal method for lithium ion battery application.

    Science.gov (United States)

    Lee, Hye Rim; Kim, Hwan Jin; Park, Jong Hyeok; Yoon, Dae Ho

    2013-06-01

    Carbon-coated SnO2 nano-composite was synthesized by using a hydrothermal method in a one step process with sizes of 1 to 3 microm. The carbon-coated SnO2 nano-composite was easily obtained by changing firing atmosphere from air to argon (600 degrees C for 3 hours). The carbon-coating thickness and size of the SnO2 nanoparticles in carbon-coated SnO2 nano-composite were confirmed through a high-resolution transmission electron microscopy (HRTEM) as 40 and 5 nm, respectively. Carbon-coating and particle size affect to the capacity retention property. Carbon-coated and non carbon-coated samples were investigated as anode materials. It was confirmed that the non carbon-coated SnO2 nano-composite had a 718 mA h/g initial charge capacity, 91% reached to theoretical value of SnO2 (790 mA h/g), while the carbon-coated SnO2 nano-composite had an excellent capacity retention of 89.6% after 70 cycles (10.88% for non carbon-coated SnO2 nano-composite).

  8. Photocatalytic Degradation of Rhodamine B Dye over Novel Porous TiO2-SnO2 Nanocomposites Prepared by Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Yan Wang

    2014-01-01

    Full Text Available The photocatalytic degradation of Rhodamine B dye was successfully carried out under UV irradiation over porous TiO2-SnO2 nanocomposites with various molar ratios of Ti/Sn (4–12 synthesized by hydrothermal method using polystyrene microspheres as template. The combination of TiO2 with SnO2 can obtain high quantum yield of TiO2, and then achieve the high photocatalytic activity. And its porous structure can provide large surface area, leading to more adsorption and fast transfer of dye pollutant. Structural and textural features of the samples were investigated by X-ray diffraction (XRD, transmission electron microscopy (TEM, and N2 sorption techniques. Both adsorption and UV irradiation contribute to decolorization of about 100% of Rhodamine B dye over the sample TiSn10 after 30 min of the photocatalytic reaction, while the decomposition of Rhodamine B dye is only 62% over pure titania (Degussa P25.

  9. Synthesis of nanoparticles of barium strontium titanate using hydrothermal microwave method; Sintese de nanoparticulas de titanato de bario estroncio utilizando o metodo hidrotermal assistido por microondas

    Energy Technology Data Exchange (ETDEWEB)

    Silva, R.A.; Souza, A.E.; Teixeira, S.R. [Universidade Estadual Paulista (DFQB/FCT/UNESP), Presidente Prudente, SP (Brazil). Fac. de Ciencia e Tecnologia. Dept. de Fisica, Quimica e Biologia; Moreira, M.L.; Volanti, D.P. [Universidade Federal de Sao Carlos (LiEC/UFSCAR), SP (Brazil). Lab. Interdisciplinar de Eletroquimica e Ceramica; Longo, E. [Universidade Estadual Paulista (UNESP/LiEC), Araraquara, SP (Brazil). Lab. Interdisciplinar de Eletroquimica e Ceramica

    2009-07-01

    Nanoparticles of barium strontium titanate Ba{sub x}Sr{sub 1}-{sub x}TiO{sub 3} (BST) had been prepared, with x = 0.5, using the hydrothermal method attended by microwaves (HTMW). A solution was prepared using deionized water, barium chloride (BaCl{sub 2}.2H{sub 2}O), strontium chloride (SrCl{sub 2}.6H{sub 2}O), titanium (IV) isopropoxide (C{sub 12}H28O{sub 4}Ti) and potassium hydroxide (KOH). Afterward the solution was heated to 140 deg C in a microwave oven, at a heating rate of 140 deg C/min, and maintained at this temperature for 40 min, under a pressure of 3 to 4 bar. X-ray diffraction (DRX) and field emission scanning electron microscopy (FE-SEM) had been used in the particles characterization. DRX was used to identify the crystallized phases and the images taken from (FE-SEM) show that the material has a wide particle-size distribution with most of them between 10 and 30 nm. (author)

  10. EXAFS analysis of cations distribution in structure of Co1-xNixFe2O4 nanoparticles obtained by hydrothermal method in aloe vera extract solution

    Science.gov (United States)

    Wongpratat, Unchista; Maensiri, Santi; Swatsitang, Ekaphan

    2016-09-01

    Effect of cations distribution upon EXAFS analysis on magnetic properties of Co1-xNixFe2O4 (x = 0, 0.25, 0.50, 0.75 and 1.0) nanoparticles prepared by the hydrothermal method in aloe vera extract solution were studied. XRD analysis confirmed a pure phase of cubic spinel ferrite of all samples. Changes in lattice parameter and particle size depended on the Ni content with partial substitution and site distributions of Co2+, Ni2+ ions of different ionic radii at both tetrahedral and octahedral sites in the crystal structure. Particle sizes of samples estimated by TEM images were found to be in the range of 10.87-62.50 nm. The VSM results at room temperature indicated the ferrimagnetic behavior of all samples. Superparamagnetic behavior was observed in NiFe2O4 sample. The coercivity (Hc) and remanance (Mr) values were related to the particle sizes of samples. The saturation magnetization (Ms) was increased by a factor of 1.4 to a value of 57.57 emu/g, whereas the coercivity (Hc) was decreased by a factor of 20 to a value of 63.15 Oe for a sample with x = 0.75. In addition to the cations distribution, the increase of aspect ratio (surface to volume ratio) due to the decrease of particle size could significantly affect the magnetic properties of the materials.

  11. The Mistreatment of Women during Childbirth in Health Facilities Globally: A Mixed-Methods Systematic Review

    Science.gov (United States)

    Bohren, Meghan A.; Vogel, Joshua P.; Hunter, Erin C.; Lutsiv, Olha; Makh, Suprita K.; Souza, João Paulo; Aguiar, Carolina; Saraiva Coneglian, Fernando; Diniz, Alex Luíz Araújo; Tunçalp, Özge; Javadi, Dena; Oladapo, Olufemi T.; Khosla, Rajat; Hindin, Michelle J.; Gülmezoglu, A. Metin

    2015-01-01

    Background Despite growing recognition of neglectful, abusive, and disrespectful treatment of women during childbirth in health facilities, there is no consensus at a global level on how these occurrences are defined and measured. This mixed-methods systematic review aims to synthesize qualitative and quantitative evidence on the mistreatment of women during childbirth in health facilities to inform the development of an evidence-based typology of the phenomenon. Methods and Findings We searched PubMed, CINAHL, and Embase databases and grey literature using a predetermined search strategy to identify qualitative, quantitative, and mixed-methods studies on the mistreatment of women during childbirth across all geographical and income-level settings. We used a thematic synthesis approach to synthesize the qualitative evidence and assessed the confidence in the qualitative review findings using the CERQual approach. In total, 65 studies were included from 34 countries. Qualitative findings were organized under seven domains: (1) physical abuse, (2) sexual abuse, (3) verbal abuse, (4) stigma and discrimination, (5) failure to meet professional standards of care, (6) poor rapport between women and providers, and (7) health system conditions and constraints. Due to high heterogeneity of the quantitative data, we were unable to conduct a meta-analysis; instead, we present descriptions of study characteristics, outcome measures, and results. Additional themes identified in the quantitative studies are integrated into the typology. Conclusions This systematic review presents a comprehensive, evidence-based typology of the mistreatment of women during childbirth in health facilities, and demonstrates that mistreatment can occur at the level of interaction between the woman and provider, as well as through systemic failures at the health facility and health system levels. We propose this typology be adopted to describe the phenomenon and be used to develop measurement tools

  12. Facile preparation of Ni{sub 2}P/ZnO core/shell composites by a chemical method and its photocatalytic performance

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Shuling, E-mail: shulingliu@aliyun.com [Key Laboratory of Auxiliary Chemistry & Technology for Chemical Industry, Ministry of Education, Shaanxi University of Science & Technology, Xi’an, Shaanxi 710021 (China); College of Chemistry & Chemical Engineering, Shaanxi University of Science & Technology, Xi’an, Shaanxi 710021 (China); Ma, Lanbing; Zhang, Hongzhe; Ma, Chenlu [Key Laboratory of Auxiliary Chemistry & Technology for Chemical Industry, Ministry of Education, Shaanxi University of Science & Technology, Xi’an, Shaanxi 710021 (China); College of Chemistry & Chemical Engineering, Shaanxi University of Science & Technology, Xi’an, Shaanxi 710021 (China)

    2016-05-15

    Graphical abstract: The typical SEM images and the schematic illustration of photocatalytic mechanism of as-prepared Ni{sub 2}P/ZnO core/shell composites. - Highlights: • Ni{sub 2}P/ZnO composites have been synthesized via a facile chemical precipitation method. • The effect of the amount of Zn{sup 2+} has been discussed. • Ni{sub 2}P/ZnO composite exhibits an enhanced photocatalytic degradation activity. • A mechanism about the enhanced photocatalytic activity is proposed. - Abstract: Ni{sub 2}P/ZnO core/shell composites were fabricated basing on combining hydrothermal route with a facile chemical precipitation method. The characterization results show that the composites are comprised of the hexagonal Ni{sub 2}P microspheres and hexagonal ZnO nanoparticles. In which, ZnO nanoparticles coat on the surfaces of Ni{sub 2}P microspheres and some of them even assemble to worm-like structure. During the coating process, Zn{sup 2+} was absorbed on the surface of Ni{sub 2}P microspheres by electrostatic interaction and then formed ZnO shell. But excessive Zn{sup 2+} can affect the crystalline and formation of core-shell structure of Ni{sub 2}P/ZnO composites, so it is necessary to control the amount of Zn{sup 2+}. Choosing Methylene Blue (MB) as a typical organic dye, the as-prepared Ni{sub 2}P/ZnO core/shell composites show the enhanced photocatalytic degradation activity, which may be due to its better adsorption ability and the effective separation of photogenerated electron–hole pairs.

  13. The analysis and selection of methods and facilities for cutting of naturally-deficit materials

    Science.gov (United States)

    Akhmetov, I. D.; Zakirova, A. R.; Sadykov, Z. B.

    2016-06-01

    The comparison of perspective methods is done in the article, such as laser, plasma and combined electro-diamond methods of hard processed materials cutting. There are the review and analysis of naturally-deficit materials cutting facilities. A new electrode-tool for the combined cutting of naturally-deficit materials is suggested. This electrode-tool eliminates electrical contact between the cutting electrode-tool and side surfaces of the channel of cutting workpiece cut, which allows to obtain coplanar channels of cut.

  14. Preparation of hollow silica nanospheres in O/W microemulsion system by hydrothermal temperature changes

    Science.gov (United States)

    Wang, Dandan; Li, Xiuyan; Liu, Zuohua; Shi, Xue; Zhou, Guowei

    2017-01-01

    Hollow silica nanospheres with wrinkled or smooth surfaces were successfully fabricated through a hydrothermal method. In this method, oil-in-water microemulsion (composed of cyclohexane, water, ethanol, and cetyltrimethylammonium bromide), and polyvinylpyrrolidone were utilized as template and capping agent, respectively. In such a facile synthesis, we can well realize the morphological transformation of spheres with radially oriented mesochannels to hollow structures of silica nanoparticle only by regulating the hydrothermal temperature from 100 °C to 200 °C. Synthesized samples with different mesostructures were then used as supports to immobilize Candida rugosa lipase (CRL). The immobilized CRL was employed as a new biocatalyst for biodiesel production through the esterification of heptanoic acid with ethanol. The conversion ratio of heptanoic acid with ethanol catalyzed by the immobilized CRL was also evaluated. Results of this study suggest that the prepared samples have potential applications in biocatalysis.

  15. A Facile Method to In-Situ Synthesize Porous Ni₂GeO₄ Nano-Sheets on Nickel Foam as Advanced Anode Electrodes for Li-Ion Batteries.

    Science.gov (United States)

    Ma, Delong; Shi, Xiaomin; Hu, Anming

    2016-11-19

    A strategy for growth of porous Ni₂GeO₄ nanosheets on conductive nickel (Ni) foam with robust adhesion as a high-performance electrode for Li-ion batteries is proposed and realized, through a facile two-step method. It involves the low temperature hydro-thermal synthesis of bimetallic (Ni, Ge) hydroxide nanosheets precursor on Ni foam substrates and subsequent thermal transformation to porous Ni₂GeO₄ nanosheets. The as-prepared Ni₂GeO₄ nanosheets possess many interparticle mesopores with a size range from 5 to 15 nm. The hierarchical structure of porous Ni₂GeO₄ nanosheets supported by Ni foam promises fast electron and ion transport, large electroactive surface area, and excellent structural stability. The efficacy of the specially designed structure is demonstrated by the superior electrochemical performance of the generated Ni₂GeO₄ nanosheets including a high capacity of 1.8 mA·h·cm(-2) at a current density of 50 μA·cm(-2), good cycle stability, and high power capability at room temperature. Because of simple conditions, this fabrication strategy may be easily extended to other mixed metal oxides (MxGeOy).

  16. Hydrothermal liquefaction of biomass

    DEFF Research Database (Denmark)

    Toor, Saqib; Rosendahl, Lasse; Rudolf, Andreas

    2011-01-01

    This article reviews the hydrothermal liquefaction of biomass with the aim of describing the current status of the technology. Hydrothermal liquefaction is a medium-temperature, high-pressure thermochemical process, which produces a liquid product, often called bio-oil or bi-crude. During...... the hydrothermal liquefaction process, the macromolecules of the biomass are first hydrolyzed and/or degraded into smaller molecules. Many of the produced molecules are unstable and reactive and can recombine into larger ones. During this process, a substantial part of the oxygen in the biomass is removed...... by dehydration or decarboxylation. The chemical properties of bio-oil are highly dependent of the biomass substrate composition. Biomass constitutes of various components such as protein; carbohydrates, lignin and fat, and each of them produce distinct spectra of compounds during hydrothermal liquefaction...

  17. One-Step Synthesis of High-Quality Water-Soluble CdSe Quantum Dots Capped by N-Acetyl-L-cysteine via Hydrothermal Method and Their Characterization

    OpenAIRE

    Chunjin Wei; Jinyu Li; Fang Gao; Shuxia Guo; Yongcui Zhou; Dan Zhao

    2015-01-01

    Novel water-soluble CdSe quantum dots (QDs) have been prepared with N-acetyl-L-cysteine as new stabilizer through a one-step hydrothermal route. The influence of experimental conditions, including reaction time, molar ratio of reactants, and pH value, on the luminescent properties of the obtained CdSe QDs has been systematically investigated. The characterization of as-prepared QDs was carried out through different methods. In particular, we realized qualitative and semiquantitative studies o...

  18. Pretreatment methods to obtain pumpable high solid loading wood–water slurries for continuous hydrothermal liquefaction systems

    DEFF Research Database (Denmark)

    Dãrãbana, Iulia-Maria; Rosendahl, Lasse Aistrup; Pedersen, Thomas Helmer

    2015-01-01

    Feedstock pretreatment is a prerequisite step for continuous processing of lignocellulosic biomass through HTL, in order to facilitate the pumpability of biomass aqueous slurries. Until now, HTL feedstock pumpability could only be achieved at solid mass content below 15%. In this work, two...... pretreatment methods to obtain wood-based slurries with more than 20% solid mass content, for continuous processing in HTL systems, are proposed. The effect of biomass particle size and pretreatment method on the feedstock pumpability is analyzed. The experimental results show that pumpable wood-based slurries...... containing 20% solids can be prepared using recycle HTL biocrude as carrier fluid, if particles smaller than 0.125 mm are used. The recycle biocrude concentration used for slurry make-up is strongly affected by the sawdust size distribution. A second pretreatment option is feedstock thermal treatment...

  19. Heat and mass flux estimation of modern seafloor hydrothermal activity

    Institute of Scientific and Technical Information of China (English)

    ZHAI Shikui; WANG Xingtao; YU Zenghui

    2006-01-01

    Research on heat and mass flux yielded by modern seafloor hydrothermal activity is very important, because it is involved not only in the base of ocean environment research, but also in the historical evolution of seawater properties. Currently, estimating heat flux is based on the observation data of hydrothermal smokers, low-temperature diffusive flow and mid-ocean ridge mainly. But there are some faults, for example, there is lack of a concurrent conductive item in estimating the heat flux by smokers and the error between the half-space cooling model and the observation data is too large. So, three kinds of methods are applied to re-estimating the heat flux of hydrothermal activity resepectively, corresponding estimation is 97.359 GW by hydrothermal smoker and diffusive flow, 84.895 GW by hydrothermal plume, and 4.11 TW by exponential attenuation method put forward by this paper. Research on mass flux estimation is relatively rare, the main reason for this is insufficient field observation data. Mass fluxes of different elements are calculated using hydrothermal vent fluid data from the TAG hydrothermal area on the Mid-Atlantic Ridge for the first time. Difference of estimations by different methods reflects the researching extent of hydrothermal activity, and systematically in-situ observation will help to estimate the contribution of hydrothermal activity to ocean chemical environment, ocean circulation and global climate precisely.

  20. Hydrothermal pretreatment of palm oil empty fruit bunch

    Science.gov (United States)

    Simanungkalit, Sabar Pangihutan; Mansur, Dieni; Nurhakim, Boby; Agustin, Astrid; Rinaldi, Nino; Muryanto, Fitriady, Muhammad Ariffudin

    2017-01-01

    Hydrothermal pretreatment methods in 2nd generation bioethanol production more profitable to be developed, since the conventional pretreatment, by using acids or alkalis, is associated with the serious economic and environmental constraints. The current studies investigate hydrothermal pretreatment of palm oil empty fruit bunch (EFB) in a batch tube reactor system with temperature and time range from 160 to 240 C and 15 to 30 min, respectively. The EFB were grinded and separated into 3 different particles sizes i.e. 10 mesh, 18 mesh and 40 mesh, prior to hydrothermal pretreatment. Solid yield and pH of the treated EFB slurries changed over treatment severities. The chemical composition of EFB was greatly affected by the hydrothermal pretreatment especially hemicellulose which decreased at higher severity factor as determined by HPLC. Both partial removal of hemicellulose and migration of lignin during hydrothermal pretreatment caused negatively affect for enzymatic hydrolysis. This studies provided important factors for maximizing hydrothermal pretreatment of EFB.

  1. Testing of the Defense Waste Processing Facility Cold Chemical Dissolution Method in Sludge Batch 9 Qualification

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Pareizs, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Coleman, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Young, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Brown, L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-05-10

    For each sludge batch that is processed in the Defense Waste Processing Facility (DWPF), the Savannah River National Laboratory (SRNL) tests the applicability of the digestion methods used by the DWPF Laboratory for elemental analysis of Sludge Receipt and Adjustment Tank (SRAT) Receipt samples and SRAT Product process control samples. DWPF SRAT samples are typically dissolved using a method referred to as the DWPF Cold Chemical or Cold Chem Method (CC), (see DWPF Procedure SW4- 15.201). Testing indicates that the CC method produced mixed results. The CC method did not result in complete dissolution of either the SRAT Receipt or SRAT Product with some fine, dark solids remaining. However, elemental analyses did not reveal extreme biases for the major elements in the sludge when compared with analyses obtained following dissolution by hot aqua regia (AR) or sodium peroxide fusion (PF) methods. The CC elemental analyses agreed with the AR and PF methods well enough that it should be adequate for routine process control analyses in the DWPF after much more extensive side-by-side tests of the CC method and the PF method are performed on the first 10 SRAT cycles of the Sludge Batch 9 (SB9) campaign. The DWPF Laboratory should continue with their plans for further tests of the CC method during these 10 SRAT cycles.

  2. An improved method for lifting and transporting anesthetized pigs within an animal facility

    DEFF Research Database (Denmark)

    Schumacher-Petersen, Camilla; Hammelev, Karsten Pharao; Flescher, Jens Erik

    2014-01-01

    Transporting anesthetized pigs in a laboratory setting often requires strenuous manual lifting, posing a hazard to the safety of animal care personnel and to the welfare of the pigs. The authors developed an improved approach to lifting and transporting anesthetized pigs weighing up to 350 kg using...... mechanical lifts. Different equipment was used to accommodate pigs of different sizes as well as the building designs of three animal facilities. Using the lifts, anesthetized pigs are carried on sheets to maintain their comfort while being transported. The approach refines previous methods for handling...

  3. Facile method to enhance the adhesion of TiO₂ nanotube arrays to Ti substrate.

    Science.gov (United States)

    Yu, Dongliang; Zhu, Xufei; Xu, Zhen; Zhong, Xiaomin; Gui, Qunfang; Song, Ye; Zhang, Shaoyu; Chen, Xiaoyuan; Li, Dongdong

    2014-06-11

    The weak adhesion of anodic TiO2 nanotube arrays (TNTAs) to the underlying Ti substrate compromises many promising applications. In this work, a compact oxide layer between TNTAs and Ti substrate is introduced by employing an additional anodization in a fluoride-free electrolyte. The additional anodization results in an about 200 nm thick compact layer near the nanotube bottoms. Scratch test demonstrates that the critical load of TNTAs with the compact oxide layer is a more than threefold increase in comparison with those without the compact layer. Moreover, this facile method can also improve the photoactivity and supercapacitor performances of TNTAs markedly.

  4. A facile method for reversibly linking a recombinant protein to DNA.

    Science.gov (United States)

    Goodman, Russell P; Erben, Christoph M; Malo, Jonathan; Ho, Wei M; McKee, Mireya L; Kapanidis, Achillefs N; Turberfield, Andrew J

    2009-06-15

    We present a facile method for linking recombinant proteins to DNA. It is based on the nickel-mediated interaction between a hexahistidine tag (His(6)-tag) and DNA functionalized with three nitrilotriacetic acid (NTA) groups. The resulting DNA-protein linkage is site-specific. It can be broken quickly and controllably by the addition of a chelating agent that binds nickel. We have used this new linker to bind proteins to a variety of DNA motifs commonly used in the fabrication of nanostructures by DNA self-assembly.

  5. A facile method for the preparation of Eu{sup 2+}-doped nanocrystalline BaFCl

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xianglei; Liu, Zhiqiang [School of Physical, Environmental and Mathematical Sciences, The University of New South Wales, UNSW Canberra (ADFA), Canberra, ACT 2600 (Australia); Stevens-Kalceff, Marion A. [School of Physics and Electron Microscope Unit, Mark Wainwright Analytical Centre, The University of New South Wales, Sydney, NSW 2052 (Australia); Riesen, Hans, E-mail: h.riesen@adfa.edu.au [School of Physical, Environmental and Mathematical Sciences, The University of New South Wales, UNSW Canberra (ADFA), Canberra, ACT 2600 (Australia)

    2013-10-15

    Graphical abstract: - Highlights: • A facile co-precipitation method for the preparation of Eu{sup 2+}-doped BaFCl. • Reduction of Eu{sup 3+} to Eu{sup 2+} by zinc granular under nitrogen flow. • Photoluminescence and cathodoluminescence spectroscopy of the as-prepared BaFCl:Eu{sup 2+}. • Temperature dependent photoluminescence properties of Eu{sup 2+} ions in BaFCl. - Abstract: A facile method for the preparation of Eu{sup 2+}-doped BaFCl is reported. The method is based on the co-precipitation of aqueous solutions of BaCl{sub 2} and NH{sub 4}F to yield BaFCl. The doping by europium in the 2+ oxidation state is realized by the reduction of Eu{sup 3+} to Eu{sup 2+} employing granular zinc in the BaCl{sub 2} solution under nitrogen. Powder X-ray diffraction and electron microscopy have been used to confirm the BaFCl phase and photoluminescence, in the temperature range of 2.5–290 K, and room-temperature cathodoluminescence spectra have been measured to characterize the Eu{sup 2+} ions in the sample.

  6. Electrical and photocatalytic properties of boron-doped ZnO nanostructure grown on PET-ITO flexible substrates by hydrothermal method.

    Science.gov (United States)

    Wang, Wei; Ai, Taotao; Yu, Qi

    2017-02-13

    Boron-doped zinc oxide sheet-spheres were synthesized on PET-ITO flexible substrates using a hydrothermal method at 90 °C for 5 h. The results of X-ray diffraction and X-ray photoelectron spectroscopy indicated that the B atoms were successfully doped into the ZnO lattice, the incorporation of B led to an increase in the lattice constant of ZnO and a change in its internal stress. The growth mechanism of pure ZnO nanorods and B-doped ZnO sheet-spheres was specifically investigated. The as-prepared BZO/PET-ITO heterojunction possessed obvious rectification properties and its positive turn-on voltage was 0.4 V. The carrier transport mechanisms involved three models such as hot carrier tunneling theory, tunneling recombination, and series-resistance effect were explored. The BZO/PET-ITO nanostructures were more effective than pure ZnO to degrade the RY 15, and the degradation rate reached 41.45%. The decomposition process with BZO nanostructure followed first-order reaction kinetics. The photocurrent and electrochemical impedance spectroscopy revealed that the B-doping could promote the separation of photo-generated electron-hole pairs, which was beneficial to enhance the photocatalytic activity. The photocurrent density of B-doped and pure ZnO/PET-ITO were 0.055 mA/cm(2) and 0.016 mA/cm(2), respectively. The photocatalytic mechanism of the sample was analyzed by the energy band theory.

  7. Electrical and photocatalytic properties of boron-doped ZnO nanostructure grown on PET–ITO flexible substrates by hydrothermal method

    Science.gov (United States)

    Wang, Wei; Ai, Taotao; Yu, Qi

    2017-02-01

    Boron-doped zinc oxide sheet-spheres were synthesized on PET–ITO flexible substrates using a hydrothermal method at 90 °C for 5 h. The results of X-ray diffraction and X-ray photoelectron spectroscopy indicated that the B atoms were successfully doped into the ZnO lattice, the incorporation of B led to an increase in the lattice constant of ZnO and a change in its internal stress. The growth mechanism of pure ZnO nanorods and B-doped ZnO sheet-spheres was specifically investigated. The as-prepared BZO/PET–ITO heterojunction possessed obvious rectification properties and its positive turn-on voltage was 0.4 V. The carrier transport mechanisms involved three models such as hot carrier tunneling theory, tunneling recombination, and series-resistance effect were explored. The BZO/PET–ITO nanostructures were more effective than pure ZnO to degrade the RY 15, and the degradation rate reached 41.45%. The decomposition process with BZO nanostructure followed first-order reaction kinetics. The photocurrent and electrochemical impedance spectroscopy revealed that the B-doping could promote the separation of photo-generated electron-hole pairs, which was beneficial to enhance the photocatalytic activity. The photocurrent density of B-doped and pure ZnO/PET–ITO were 0.055 mA/cm2 and 0.016 mA/cm2, respectively. The photocatalytic mechanism of the sample was analyzed by the energy band theory.

  8. Characterization and applications of as-grown {beta}-Fe{sub 2}O{sub 3} nanoparticles prepared by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, Mohammed M., E-mail: mmrahmanh@gmail.com; Jamal, Aslam; Khan, Sher Bahadar; Faisal, Mohd [Najran University, Department of Chemistry, Faculty of Sciences and Arts (Saudi Arabia)

    2011-09-15

    The production of low-dimensional nanoparticles (NPs) with appropriate surface modification has attracted increasing attention in biological, biochemical, and environmental applications including chemical sensing, photocatalytic degradation, separation, and purification of toxic molecules from the matrices. In this study, iron oxide NPs have been prepared by hydrothermal method using ferric chloride and urea in aqueous medium under alkaline condition (pH 9 {approx} 10). As-grown low-dimensional NPs have been characterized by UV-vis spectroscopy, FT-IR, X-ray diffraction, Field emission scanning electron microscopy, Raman spectroscopy, High-resolution Transmission electron microscopy, and Electron Diffraction System. The uniformity of the NPs size was measured by the scanning electron microscopy, while the single phase of the nanocrystalline {beta}-Fe{sub 2}O{sub 3} was characterized using powder X-ray diffraction technique. As-grown NPs were extensively applied for the photocatalytic degradation of acridine orange (AO) and electrochemical sensing of ammonia in liquid phase. Almost 50% photo-catalytic degradation with AO was observed in the presence of UV sources (250 W) with NPs. {beta}-Fe{sub 2}O{sub 3} NP-coated gold electrodes (GE, surface area 0.0216 cm{sup 2}) have enhanced ammonia-sensing performances in their electrical response (I-V characterization) for detecting ammonia in liquid phase. The performances of chemical sensor were investigated, and the results exhibited that the sensitivity, stability, and reproducibility of the sensor improved significantly using {beta}-Fe{sub 2}O{sub 3} NPs on GE surface. The sensitivity was approximately 0.5305 {+-} 0.02 {mu}Acm{sup -2}mM{sup -1}, with a detection limit of 21.8 {+-} 0.1 {mu}M, based on a signal/noise ratio of 3 with short response time.

  9. Characterization and magnetic properties of SrTi{sub 1−x}Ni{sub x}O{sub 3} nanoparticles prepared by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Karaphun, Attaphol [Integrated Nanotechnology Research Center, Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Hunpratub, Sitchai; Phokha, Sumalin [Department of Physics, Faculty of Science, Rajabhat Udon Thani University, Udon Thani 41000 (Thailand); Putjuso, Thanin [Rajamangala University of Technology Rattanakosin Wang Klai Kangwon Campus, Prachuap Khiri Khan 77110 (Thailand); Swatsitang, Ekaphan, E-mail: ekaphan@kku.ac.th [Integrated Nanotechnology Research Center, Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Nanotec-KKU Center of Excellence on Advanced Nanomaterials for Energy Production and Storage, Khon Kaen 40002 (Thailand)

    2017-01-01

    SrTi{sub 1−x}Ni{sub x}O{sub 3} (x=0, 0.05, 0.10 and 0.15) nanoparticles were prepared by the hydrothermal method. All as-prepared samples were annealed at 800 °C for 3 h in argon to study the annealing effect on their magnetic properties. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray absorption near edge spectroscopy (XANES), X-ray photoelectron spectroscopy (XPS) and vibrating sample magnetometry (VSM) were used to study the crystalline structure, morphology, oxidation state and magnetic properties of samples. XRD results indicate a cubic perovskite structure of all samples with the impurity phase of SrCO{sub 3} in all as-prepared samples and Ni metal in annealed samples of x=0.10 and 0.15. SEM and TEM images confirmed a cubic shape for all samples with decreasing average particle sizes from 136.8±4.7 to 126.2±6.9 nm for annealed samples upon Ni doping. XANES results revealed the existence of Ni metal in sample of x=0.05 with the oxidation state of +2 for Ni ion in a SrTi{sub 0.95}Ni{sub 0.05}O{sub 3} sample. XPS results indicated the promotion of oxygen vacancies. VSM results revealed a paramagnetic behavior at room temperature of all as-prepared samples. Ni-doped samples exhibited ferromagnetic behavior after annealing in argon with the Curie temperature (T{sub C}) above 380 K for a sample with x=0.05 as shown by field cooling (FC) and zero-field cooling (ZFC) measurements. The room temperature ferromagnetism (RT-FM) of ferromagnetic samples was suggested to be originated from Ni metal and F-center exchange (FCE) mechanism due to the promotion of oxygen vacancies in the perovskite structure.

  10. A systematic method for identifying vital areas at complex nuclear facilities.

    Energy Technology Data Exchange (ETDEWEB)

    Beck, David Franklin; Hockert, John

    2005-05-01

    Identifying the areas to be protected is an important part of the development of measures for physical protection against sabotage at complex nuclear facilities. In June 1999, the International Atomic Energy Agency published INFCIRC/225/Rev.4, 'The Physical Protection of Nuclear Material and Nuclear Facilities.' This guidance recommends that 'Safety specialists, in close cooperation with physical protection specialists, should evaluate the consequences of malevolent acts, considered in the context of the State's design basis threat, to identify nuclear material, or the minimum complement of equipment, systems or devices to be protected against sabotage.' This report presents a structured, transparent approach for identifying the areas that contain this minimum complement of equipment, systems, and devices to be protected against sabotage that is applicable to complex nuclear facilities. The method builds upon safety analyses to develop sabotage fault trees that reflect sabotage scenarios that could cause unacceptable radiological consequences. The sabotage actions represented in the fault trees are linked to the areas from which they can be accomplished. The fault tree is then transformed (by negation) into its dual, the protection location tree, which reflects the sabotage actions that must be prevented in order to prevent unacceptable radiological consequences. The minimum path sets of this fault tree dual yield, through the area linkage, sets of areas, each of which contains nuclear material, or a minimum complement of equipment, systems or devices that, if protected, will prevent sabotage. This method also provides guidance for the selection of the minimum path set that permits optimization of the trade-offs among physical protection effectiveness, safety impact, cost and operational impact.

  11. Nanoplate-like tungsten trioxide (hydrate) films prepared by crystal-seed-assisted hydrothermal reaction

    Science.gov (United States)

    Wang, P.; Yang, L.; Dai, B.; Yang, Z.; Guo, S.; Zhu, J.

    2017-07-01

    Vertically-aligned WO3 nanoplates on transparent conducting fluorine-doped tin oxide (FTO) glass were prepared by a facile template-free crystal-seed-assisted hydrothermal method. The effects of the hydrothermal temperature and reaction time on the crystal structure and morphology of the products were investigated by XRD and SEM. The XRD results showed that the as-prepared thin films obtained below 150∘C comprised orthorhombic WO3 ṡ H2O and completely converted to monoclinic WO3 at 180∘C. It was also noted that there was a phase transformation from orthorhombic to monoclinic by increasing the reaction time from 1 to 12 h. SEM analysis revealed that WO3 thin films are composed of plate-like nanostructures.

  12. Hydrothermal Fabrication of WO3 Hierarchical Architectures: Structure, Growth and Response

    Directory of Open Access Journals (Sweden)

    Chuan-Sheng Wu

    2015-07-01

    Full Text Available Recently hierarchical architectures, consisting of two-dimensional (2D nanostructures, are of great interest for potential applications in energy and environmental. Here, novel rose-like WO3 hierarchical architectures were successfully synthesized via a facile hydrothermal method. The as-prepared WO3 hierarchical architectures were in fact assembled by numerous nanosheets with an average thickness of ~30 nm. We found that the oxalic acid played a significant role in governing morphologies of WO3 during hydrothermal process. Based on comparative studies, a possible formation mechanism was also proposed in detail. Furthermore, gas-sensing measurement showed that the well-defined 3D WO3 hierarchical architectures exhibited the excellent gas sensing properties towards CO.

  13. Analysis of Unit Process Cost for an Engineering-Scale Pyroprocess Facility Using a Process Costing Method in Korea

    National Research Council Canada - National Science Library

    Sungki Kim; Wonil Ko; Sungsig Bang

    2015-01-01

    ...) metal ingots in a high-temperature molten salt phase. This paper provides the unit process cost of a pyroprocess facility that can process up to 10 tons of pyroprocessing product per year by utilizing the process costing method...

  14. Catalytic Hydrothermal Gasification

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, Douglas C.

    2015-05-31

    The term “hydrothermal” used here refers to the processing of biomass in water slurries at elevated temperature and pressure to facilitate the chemical conversion of the organic structures in biomass into useful fuels. The process is meant to provide a means for treating wet biomass materials without drying and to access ionic reaction conditions by maintaining a liquid water processing medium. Typical hydrothermal processing conditions are 523-647K of temperature and operating pressures from 4-22 MPa of pressure. The temperature is sufficient to initiate pyrolytic mechanisms in the biopolymers while the pressure is sufficient to maintain a liquid water processing phase. Hydrothermal gasification is accomplished at the upper end of the process temperature range. It can be considered an extension of the hydrothermal liquefaction mechanisms that begin at the lowest hydrothermal conditions with subsequent decomposition of biopolymer fragments formed in liquefaction to smaller molecules and eventually to gas. Typically, hydrothermal gasification requires an active catalyst to accomplish reasonable rates of gas formation from biomass.

  15. METHODS FOR DETERMINING AGITATOR MIXING REQUIREMENTS FOR A MIXING & SAMPLING FACILITY TO FEED WTP (WASTE TREATMENT PLANT)

    Energy Technology Data Exchange (ETDEWEB)

    GRIFFIN PW

    2009-08-27

    The following report is a summary of work conducted to evaluate the ability of existing correlative techniques and alternative methods to accurately estimate impeller speed and power requirements for mechanical mixers proposed for use in a mixing and sampling facility (MSF). The proposed facility would accept high level waste sludges from Hanford double-shell tanks and feed uniformly mixed high level waste to the Waste Treatment Plant. Numerous methods are evaluated and discussed, and resulting recommendations provided.

  16. Synthesis and Characterization of Bismuth-doped Zinc Oxide Nano-powders by Hydrothermal Method%铋掺杂氧化锌纳米粉体水热法制备及其表征

    Institute of Scientific and Technical Information of China (English)

    乐小芳; 谭艳; 陈燕梅; 万谦; 马粉波,; 吕维忠

    2012-01-01

    以氯化锌、硝酸铋为卡要原料,氢氧化钠为沉淀剂,采用水热法在水热温度为240℃,水热时间25h,pH为9的条件下制备了BZO粉体。刘粉末的前驱体进行了综合热分析,通过XRD物相分析和SEM分析可知,粉体成份为ZnO和Bi203的混合物,为颗粒状微粒.犬小均匀,微粒直径在100-200nm。%Bismuth-doped zinc oxide(BZO) nano-particles were prepared by hydrothermal method using ZnCI2 and Bi(NO3)3-5H2O as precursors and NaOH as precipitant, with the condition of 25 h hydrothermal time, 240℃ hydrothermal temperature, terminal pH of 7. The BZO precursors were studied by means of TG-DTA. The product particles were analyzed by means of X-ray diffraction (XRD) and scanning electron microscopy(SEM). The particles are tiny granular mixtures of ZnO and Bi203, and show well-defined crystallographic faces. The length is about 100-200 nm.

  17. Histidine-containing peptide catalysts developed by a facile library screening method.

    Science.gov (United States)

    Akagawa, Kengo; Sakai, Nobutaka; Kudo, Kazuaki

    2015-02-02

    Although peptide catalysts have a high potential for the use as organocatalysts, the optimization of peptide sequences is laborious and time-consuming. To address this issue, a facile screening method for finding efficient aminocatalysts from a peptide library has been developed. In the screening for the Michael addition of a malonate to an enal, a dye-labeled product is immobilized on resin-bound peptides through reductive amination to visualize active catalysts. This procedure allows for the monitoring of the reactivity of entire peptides without modifying the resin beads beforehand. Peptides containing histidine at an appropriate position were identified by this method. A novel function of the histidyl residue, which enhances the binding of a substrate to the catalyst by capturing an iminium intermediate, was indicated.

  18. 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.

  19. Hydrothermally reduced graphene oxide as a supercapacitor

    Science.gov (United States)

    Johra, Fatima Tuz; Jung, Woo-Gwang

    2015-12-01

    The supercapacitance behavior of hydrothermally reduced graphene oxide (RGO) was investigated for the first time. The capacitive behavior of RGO was characterized by using cyclic voltammetry and galvanostatic charge-discharge methods. The specific capacitance of hydrothermally reduced RGO at 1 A/g was 367 F/g in 1 M H2SO4 electrolyte, which was higher than that of RGO synthesized via the hydrazine reduction method. The RGO-modified glassy carbon electrode showed excellent stability. After 1000 cycles, the supercapacitance was 107.7% of that achieved in the 1st cycle, which suggests that RGO has excellent electrochemical stability as a supercapacitor electrode material. The energy density of hydrothermal RGO reached 44.4 W h/kg at a power density of 40 kW/kg.

  20. The Lassen hydrothermal system

    Science.gov (United States)

    Ingebritsen, Steven E.; Bergfeld, Deborah; Clor, Laura; Evans, William C.

    2016-01-01

    The active Lassen hydrothermal system includes a central vapor-dominated zone or zones beneath the Lassen highlands underlain by ~240 °C high-chloride waters that discharge at lower elevations. It is the best-exposed and largest hydrothermal system in the Cascade Range, discharging 41 ± 10 kg/s of steam (~115 MW) and 23 ± 2 kg/s of high-chloride waters (~27 MW). The Lassen system accounts for a full 1/3 of the total high-temperature hydrothermal heat discharge in the U.S. Cascades (140/400 MW). Hydrothermal heat discharge of ~140 MW can be supported by crystallization and cooling of silicic magma at a rate of ~2400 km3/Ma, and the ongoing rates of heat and magmatic CO2 discharge are broadly consistent with a petrologic model for basalt-driven magmatic evolution. The clustering of observed seismicity at ~4–5 km depth may define zones of thermal cracking where the hydrothermal system mines heat from near-plastic rock. If so, the combined areal extent of the primary heat-transfer zones is ~5 km2, the average conductive heat flux over that area is >25 W/m2, and the conductive-boundary length system or owe to various geologic events such as the eruption of Lassen Peak at 27 ka, deglaciation beginning ~18 ka, the eruptions of Chaos Crags at 1.1 ka, or the minor 1914–1917 eruption at the summit of Lassen Peak. However, there is a rich record of intermittent hydrothermal measurement over the past several decades and more-frequent measurement 2009–present. These data reveal sensitivity to climate and weather conditions, seasonal variability that owes to interaction with the shallow hydrologic system, and a transient 1.5- to twofold increase in high-chloride discharge in response to an earthquake swarm in mid-November 2014.

  1. 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

  2. Facility and Methods Developed for Simulated Space Vacuum Ultraviolet Exposure Testing of Polymer Films

    Science.gov (United States)

    Dever, Joyce A.; Pietromica, Anthony J.; Stueber, Thomas J.; Sechkar, Edward A.; Messer, Russell K.

    2002-01-01

    Vacuum ultraviolet (VUV) radiation of wavelengths between 115 and 200 nm produced by the Sun in the space environment can degrade polymer films, producing changes in their optical, mechanical, and chemical properties. These effects are particularly important for thin polymer films being considered for ultralightweight space structures, because, for most polymers, VUV radiation is absorbed in a thin surface layer. The NASA Glenn Research Center has developed facilities and methods for long-term ground testing of polymer films to evaluate space environmental VUV radiation effects. VUV exposure can also be used as part of combined or sequential simulated space environmental exposures to determine combined damaging effects with other aspects of the space environment, which include solar ultraviolet radiation, solar flare x-rays, electron and proton radiation, atomic oxygen (for low-Earth-orbit missions), and temperature effects. Because the wavelength sensitivity of VUV damage is not well known for most materials, Glenn's VUV facility uses a broad-spectrum deuterium lamp with a magnesium fluoride window that provides output between 115 and 200 nm. Deuterium lamps of this type were characterized by the National Institute of Standards and Technology and through measurements at Glenn. Spectral irradiance measurements show that from approximately 115 to 160 nm, deuterium lamp irradiance can be many times that of air mass zero solar irradiance, and as wavelength increases above approximately 160 nm, deuterium lamp irradiance decreases in comparison to the Sun. The facility is a cryopumped vacuum chamber that achieves a system pressure of approximately 5310(exp -6) torr. It contains four individual VUV-exposure compartments in vacuum, separated by water-cooled copper walls to minimize VUV radiation and any sample contamination cross interactions between compartments. Each VUV-exposure compartment contains a VUV deuterium lamp, a motor-controlled sample stage coupled with a

  3. Preparation of multi-functional superhydrophobic lanthanum surface on carbon steel via facile electrochemical method

    Science.gov (United States)

    Chen, Xi; He, Yi; Fan, Yi; Yang, Qiangbin; Li, Han

    2016-12-01

    We have constructed a superhydrophobic surface with lanthanum palmitate on carbon steel via a facile one-step electrodeposition. The morphology and chemical composition of the superhydrophobic surface were characterized by field-emission scanning electron microscopy with attached energy dispersive X-ray spectrum, Fourier transform infrared spectra and X-ray photoelectron spectroscopy, respectively. The as-prepared surface with hierarchical structure has a largest contact angle of 160° ± 0.5° and a lowest sliding angle of 2° ± 0.5°. We found that both high electrodeposition potential and high concentrations lanthanum nitrate can accelerate the formation of superhydrophobic film. The electrochemical measurements demonstrated that the superhydrophobic surface exhibited excellent anti-corrosion performance in 3.5 wt% NaCl solution. Moreover, we also investigated the chemical stability, self-cleaning and oil/water separation of the superhydrophobic film. We believe that the facile fabrication method provides a promising strategy to fabricate multi-functional superhydrophobic surface with lanthanide series rare-earth elements on kinds of substrates.

  4. Hydrothermal Growth and Hydrogen Selective Sensing of Nickel Oxide Nanowires

    Directory of Open Access Journals (Sweden)

    Thi Thanh Le Dang

    2015-01-01

    Full Text Available Low cost synthesis of nanostructured metal oxides for gas sensing application at low temperature is nowadays of crucial importance in many fields. Herein, NiO p-type semiconducting nanowires with polycrystalline structure were prepared by a facile and scalable hydrothermal method. Morphology and crystal structure of the NiO nanowires were investigated by scan electron microscopy, X-ray diffraction, and transmission electron microscopy. The nanostructured material was then tested as hydrogen sensor showing very good performance in terms of sensor response, stability, absence of drifts, and speed of response and recovery. The selectivity of the NiO sensor to hydrogen towards other gases (ethanol, ammonia, and liquefied petroleum gas was found to be good.

  5. A facile method for electrospinning of Ag nanoparticles/poly (vinyl alcohol)/carboxymethyl-chitosan nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yinghui; Zhou, Ying [Beijing Key Laboratory for Solid Waste Utilization and Management, College of Engineering, Peking University, Beijing 100871 (China); Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Wu, Xiaomian [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Department of Orthodontics College of Stomatology, Chongqing Medical University, Chongqing 401147 (China); Wang, Lu [Beijing Key Laboratory for Solid Waste Utilization and Management, College of Engineering, Peking University, Beijing 100871 (China); Xu, Ling, E-mail: lingxu@pku.edu.cn [Beijing Key Laboratory for Solid Waste Utilization and Management, College of Engineering, Peking University, Beijing 100871 (China); Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); PKU-HKUST ShenZhen-HongKong Institution, Shenzhen 518057 (China); Wei, Shicheng, E-mail: sc-wei@pku.edu.cn [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Department of Oral and Maxillofacial Surgery, School and Hospital of Stomatology, Peking University, Beijing 100081 (China)

    2012-09-01

    Highlights: Black-Right-Pointing-Pointer AgNPs/PVA/CM-chitosan nanofibers were prepared via electrospinning method. Black-Right-Pointing-Pointer AgNPs were in situ synthesized in electrospinning solution via a facile method. Black-Right-Pointing-Pointer AgNPs distributed homogeneously on the surface of nanofibers. Black-Right-Pointing-Pointer The prepared nanofibers possessed certain antibacterial ability against Escherichia coli. Black-Right-Pointing-Pointer The AgNPs containing nanofibers had potential as antibacterial biomaterial. - Abstract: A facile method to prepare silver nanoparticles (AgNPs) containing nanofibers via electrospinning has been demonstrated. AgNPs were in situ synthesized in poly (vinyl alcohol) (PVA)/carboxymethyl-chitosan (CM-chitosan) blend aqueous solution before electrospinning. UV-vis spectra, viscosity and conductivity of the electrospinning solution were measured to investigate their effects on the electrospinning procedure. The morphology of AgNPs/PVA/CM-chitosan nanofibers was observed by Field Emission Scanning Electron Microscopy. The formation and morphology of AgNPs were investigated by Transmission Electron Microscopy and X-ray Photoelectron Spectroscopy. The resulted nanofibers have smooth surface and uniform diameters ranging from 295 to 343 nm. The diameters of AgNPs mainly distributed in the range of 4-14 nm, and the electrostatic interaction between AgNPs and fibers was observed. Finally, in vitro Ag release from the nanofibers was measured and the antibacterial behavior of the nanofibers against Escherichia coli was studied by bacterial growth inhibition halos and bactericidal kinetic testing. The AgNPs/PVA/CM-chitosan nanofibers possessed certain antibacterial ability, which makes them capable for antibacterial biomaterials.

  6. [Simultaneous Removal of Cd (II) and Phenol by Titanium Dioxide-Titanate Nanotubes Composite Nanomaterial Synthesized Through Alkaline-Acid Hydrothermal Method].

    Science.gov (United States)

    Lei, Li; Jin, Yin-jia; Wang, Ting; Zhao, Xiao; Yan, You; Liu, Wen

    2015-07-01

    A composite nanomaterial, TiO2/TNTs, was synthesized by TiO2 (P25) through alkaline and acid hydrothermal reaction, which possessed both titanate nanotubes (TNTs) and TiO2 phase. It was found that the adsorption kinetics of Cd(II) onto TiO2/TNTs was very quick, and the adsorption could reach the equilibrium within 30 min. In addition, the maximum adsorption capacity of Cd(II) was as large as 120. 34 mg.g-1 calculated from Langmuir isotherm model. The adsorption mechanism of Cd(II) was ion-exchange between Cd2+ and Na+/H+ located in the interlayers of TNTs. However, the adsorption capacity of phenol on TiO2/TNTs was so small that the photocatalysis for phenol degradation was needed. In the adsorption-photocatalysis system, the removal efficiencies of Cd(II) and phenol could reach up to 99. 6% and 99.7%, respectively. Especially, removal of Cd(II) was attributed to adsorption by TNTs of the composite nanomaterial, while removal of phenol was resulted from photocatalytic reaction by the TiO2 phase. Moreover, the co-existing Cd(II) enhanced the photocatalytic degradation of phenol due to the enhancement on photocatalytic activity of TiO2/TNTs after Cd(II) was adsorbed. Co-existing Na+ did not show obvious effect on the co-removal of Cd(II) and phenol by TiO2/TNTs, but adsorption of Cd(II) was inhibited in the presence of Ca2+ as it could compete for the adsorption sites and enhance the aggregation of the material. Furthermore, TiO2/TNTs could be efficiently reused after desorption via HNO3 and regeneration via NaOH, and the removal efficiencies of Cd(II) and phenol were still as high as 91. 7% and 98. 1% even after three cycles. This study proposed a method to synthesize a material which had both adsorptive and photocatalytic performance, and it was of great importance for application of nanomaterials in the simultaneous removal of heavy metals and organic pollutants.

  7. 水热活化法提取粉煤灰中的氧化铝%Extracting alumina from fly ash by hydrothermal activation method

    Institute of Scientific and Technical Information of China (English)

    董宏; 张文广

    2014-01-01

    The pre-fired fly ash was dissolved with sodium hydroxide by the high-pressure hydrothermal acti-vation method .The influence factors on the dissolution rate of alumina were discussed , including the mole ratio of calcium to silicon , alkali concentration , the ratio of solid to liquid , caustic ratio , reaction temperature , reaction time, etc.Considering the dissolution rate of alumina , reaction cost and others, the optimum conditions of alumina dissolution were recognized .The results show that under condition of alkali-soluble the best experimental parame-ters include the ratio of calcium silicon molar as 1.0, the alkali concentration as 350 g/L, the ratio of solid to liq-uid as 10∶1, the caustic ratio 14, the reaction temperature as 280℃, and with the activation time of 2 h.Through optimizing the conditions of alumina dissolution process , the alumina extraction could reach more than 95% in ratio.%采用高压水热活化法对预先烧制的粉煤灰进行碱溶实验,探讨钙硅摩尔比、碱液浓度、液固比、苛性比、反应温度、反应时间等影响因素对于氧化铝溶出率的影响。考虑到氧化铝溶出率及反应成本等各方面因素,得出氧化铝溶出的适宜条件。结果表明:碱溶条件下,钙硅摩尔比为1.0,溶液碱浓度为350 g/L,液固比为10∶1,苛性比为14,反应温度280℃,活化时间为2 h。通过氧化铝溶出工艺条件的优化,可使氧化铝提取率达到95%以上。

  8. A novel, efficient and facile method for the template removal from mesoporous materials

    KAUST Repository

    Chen, Lu

    2014-11-12

    © 2014, Jilin University, The Editorial Department of Chemical Research in Chinese Universities and Springer-Verlag GmbH. A new catalytic-oxidation method was adopted to remove the templates from SBA-15 and MCM-41 mesoporous materials via Fenton-like techniques under microwave irradiation. The mesoporous silica materials were treated with different Fenton agents based on the template’s property and textural property. The samples were characterized by powder X-ray diffraction(XRD) measurement, N2 adsorption-desorption isotherms, infrared spectroscopy, 29Si MAS NMR and thermo gravimetric analysis(TGA). The results reveal that this is an efficient and facile approach to the thorough template-removal from mesoporous silica materials, as well as to offering products with more stable structures, higher BET surface areas, larger pore volumes and larger quantity of silanol groups.

  9. Facile method for liquid-exfoliated graphene size prediction by UV-visible spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, Zulhelmi, E-mail: helmie83@hotmail.com [Faculty of Manufacturing Engineering, Universiti Malaysia Pahang, 26600 Pekan, Pahang (Malaysia); Yusoh, Kamal, E-mail: kamal@ump.edu.my [Faculty of Chemical Engineering and Natural Resources, Universiti Malaysia Pahang, Lebuhraya Tun Razak, 26300 Kuantan, Pahang (Malaysia)

    2016-07-19

    In this work, an application of UV spectroscopy for facile prediction of liquid –exfoliated graphene size is discussed. Dynamic light scattering method was used to estimate the graphene flake size ( whilst UV spectroscopy measurement was carried out for extinction coefficient value (ε) determination. It was found that the value of (ε) decreased gradually as the graphene size was further reduced after intense sonication time (7h). This observation showed the influence of sonication time on electronic structure of graphene. A mathematical equation was derived from log-log graph for correlation between () and (ε) value. Both values can be expressed in a single equation as ( = (3.4 × 10{sup −2}) ε{sup 1.2}).

  10. A Facile Synthesis of Silver-Coated Composite Particles by Swelling Surface Method

    Institute of Scientific and Technical Information of China (English)

    LIU Jun-Bing; LI Neng; WANG Si-Zhen; ZHANG Jian-Hui; WANG Zhen-Lin

    2005-01-01

    @@ We report a facile and rapid method for fabrication of composite particles consisting of a polystyrene (PS) core and a uniform silver shell.The process involves the PS colloid surface swelling, the anchoring of silver ions and nanoparticles onto the surfaces, and the subsequent growth of metal seeds in a short period.The present approach has the advantages of simplicity and high efficiency.The TEM images show the morphology of the obtained PS core-silver shell particles, and their chemical composition and crystallinity are analysed by x-ray diffraction.To our knowledge, this is the first study based on swelling PS surface for synthesis of silver-coated PS particles and may be implemented for preparing other metal-coated PS particles.

  11. Evaluation of a Virtual Citizen Science Facility: A Comprehensive Mixed-Methods Approach

    Science.gov (United States)

    Bracey, G.

    2014-07-01

    The CosmoQuest Virtual Citizen Science Facility allows the public to participate in scientific research, learning opportunities, and community activities. Evaluation efforts include an online survey of users' attitudes about and use of the CosmoQuest website and their motivations for participation. Pre/post-participation assessments examine learning of science content. Along with these quantitative assessments we seek a deeper level of understanding through qualitative methods. Formative and summative evaluations use semi-structured interviews and open-ended survey questions. Participant responses are analyzed using an iterative process of open coding, allowing patterns to emerge inductively from the data. Triangulation of data increases the validity of findings. This approach gives a more rigorous look at the motivations, behaviors, and learning of participants, and a more complete and in-depth understanding of project impact.

  12. A facile method for fabricating TiO2@mesoporous carbon and three-layered nanocomposites.

    Science.gov (United States)

    Liu, Yong; Jin, Haibao; Zhu, Shenmin; Liu, Yunchun; Long, Mingce; Zhou, Yongfeng; Yan, Deyue

    2012-08-17

    Herein, we report a new and facile method for fabricating TiO(2)@mesoporous carbon hybrid materials. Uniform polydopamine (PDA) layers were coated onto the surface of titanate nanotubes (TNTs) and TiO(2) nanorods (TNDs) through the spontaneous adhesion and self-polymerization of dopamine during the dipping process. Core-shell mesoporous carbon nanotubes with TiO(2) nanorods or nanoparticles encapsulated inside (TiO(2)@MC) were then obtained by transforming PDA layers into carbonaceous ones through calcination in nitrogen at 800 °C. The thickness of the mesoporous carbon layers is tens of nanometers and can be controlled by adjusting the coated PDA layers through the self-polymerization reaction time. In addition, three-layered nanocomposites of TiO(2)@MC@MO (MO, metal oxide) can be readily prepared by utilizing PDA layers in TNTs@PDA or TNDs@PDA to adsorb the metal ions, followed by the calcination process.

  13. Facile Synthetic Method and Crystal Structure of 2, 3, 3', 4'-Biphenyltetracarboxylic Dianhydride

    Institute of Scientific and Technical Information of China (English)

    YI Shi-xu; GAO Guo-wei; YANG Mei-jia; CHEN Hua; WU Di-feng; MEN Jian

    2012-01-01

    A facile method for the synthesis of 2,3,3',4'-biphenyltetracarboxylic dianhydride(a-BPDA)was reported,which comprises the steps of the dehalogenative coupling of dimethyl 4-chlorophthalate(4-DMCP)and dimethyl3-chlorophthalate(3-DMCP)catalyzed by low-cost(Ph3P)2NiCl2,the hydrolysis of tetra-ester and the dehydration of tetra-acid.In contrast to the conventional methods,this method has the advantage of low cost,convenient manipulation,available condition,high purity and good overall yield.Moreover,the single crystal structure of a-BPDA was analyzed by X-ray diffraction method.The X-ray data suggest that a-BPDA is a rigid,non-coplanar and non-linear structure.It contains three crystallographically independent molecules,in which the dihedral angles of the two linked phenyl rings are 44.75(4)°,46.37(3)° and 42.32(3)°,respectively.The title molecule is governed by a stronger intermolecular interaction in contrast to van der Waals interaction because of the special positions of anhydride groups.

  14. Hydrothermal conversion of biomass

    NARCIS (Netherlands)

    Knezevic, Dragan

    2009-01-01

    This thesis presents research of hydrothermal conversion of biomass (HTC). In this process, hot compressed water (subcritical water) is used as the reaction medium. Therefore this technique is suitable for conversion of wet biomass/ waste streams. By working at high pressures, the evaporation of wat

  15. Hydrothermal Reactivity of Amines

    Science.gov (United States)

    Robinson, K.; Shock, E.; Hartnett, H. E.; Williams, L. B.; Gould, I.

    2013-12-01

    The reactivity of aqueous amines depends on temperature, pH, and redox state [1], all of which are highly variable in hydrothermal systems. Temperature and pH affect the ratio of protonated to unprotonated amines (R-NH2 + H+ = R-NH3+), which act as nucleophiles and electrophiles, respectively. We hypothesize that this dual nature can explain the pH dependence of reaction rates, and predict that rates will approach a maximum at pH = pKa where the ratio of protonated and unprotonated amines approaches one and the two compounds are poised to react with one another. Higher temperatures in hydrothermal systems allow for more rapid reaction rates, readily reversible reactions, and unique carbon-nitrogen chemistry in which water acts as a reagent in addition to being the solvent. In this study, aqueous benzylamine was used as a model compound to explore the reaction mechanisms, kinetics, and equilibria of amines under hydrothermal conditions. Experiments were carried out in anoxic silica glass tubes at 250°C (Psat) using phosphate-buffered solutions to observe changes in reaction rates and product distributions as a function of pH. The rate of decomposition of benzylamine was much faster at pH 4 than at pH 9, consistent with the prediction that benzylamine acts as both nucleophile and an electrophile, and our estimate that the pKa of benzylamine is ~5 at 250°C and Psat. Accordingly, dibenzylamine is the primary product of the reaction of two benzylamine molecules, and this reaction is readily reversible under hydrothermal conditions. Extremely acidic or basic pH can be used to suppress dibenzylamine production, which also suppresses the formation of all other major products, including toluene, benzyl alcohol, dibenzylimine, and tribenzylamine. This suggests that dibenzylamine is the lone primary product that then itself reacts as a precursor to produce the above compounds. Analog experiments performed with ring-substituted benzylamine derivatives and chiral

  16. Depolymerization of sulfated polysaccharides under hydrothermal conditions.

    Science.gov (United States)

    Morimoto, Minoru; Takatori, Masaki; Hayashi, Tetsuya; Mori, Daiki; Takashima, Osamu; Yoshida, Shinichi; Sato, Kimihiko; Kawamoto, Hitoshi; Tamura, Jun-ichi; Izawa, Hironori; Ifuku, Shinsuke; Saimoto, Hiroyuki

    2014-01-30

    Fucoidan and chondroitin sulfate, which are well known sulfated polysaccharides, were depolymerized under hydrothermal conditions (120-180°C, 5-60min) as a method for the preparation of sulfated polysaccharides with controlled molecular weights. Fucoidan was easily depolymerized, and the change of the molecular weight values depended on the reaction temperature and time. The degree of sulfation and IR spectra of the depolymerized fucoidan did not change compared with those of untreated fucoidan at reaction temperatures below 140°C. However, fucoidan was partially degraded during depolymerization above 160°C. Nearly the same depolymerization was observed for chondroitin sulfate. These results indicate that hydrothermal treatment is applicable for the depolymerization of sulfated polysaccharides, and that low molecular weight products without desulfation and deformation of the initial glycan structures can be obtained under mild hydrothermal conditions.

  17. A new and facile method for measurement of apparent density of monodisperse polymer beads.

    Science.gov (United States)

    Zhang, Qi; Srinivasan, Balasubramanian; Li, Yuanpeng; Jing, Ying; Xing, Chengguo; Chang, Jin; Wang, Jian-Ping

    2010-03-15

    The apparent density, an intrinsic physical property of polymer beads, plays an important role in the application of beads in micro-total analysis systems and separation. Here we have developed a new, facile and milligram-scale method to describe the motion of beads in aqueous solution and further detect the apparent density of beads. The motion of beads in solutions is determined by the viscosity of solutions and the density difference between beads and solutions. In this study, using various glycerol aqueous solutions with certain viscosities and densities, the motion time (i.e. floating or sedimentation time) of hybrid polymer beads was experimentally measured and theoretically deduced, and consequently, the apparent density of monodisperse beads can be quickly and easily calculated. The results indicated that the present method provided a more precise way to predict the movement of hybrid beads in aqueous solution compared with the approach for commercial use. This new method can be potentially employed in flow cytometry, suspension stability, and particle analysis systems.

  18. Hydrothermal growth of ZnO nanostructures - revew article

    Directory of Open Access Journals (Sweden)

    Sunandan Baruah and Joydeep Dutta

    2009-01-01

    Full Text Available One-dimensional nanostructures exhibit interesting electronic and optical properties due to their low dimensionality leading to quantum confinement effects. ZnO has received lot of attention as a nanostructured material because of unique properties rendering it suitable for various applications. Amongst the different methods of synthesis of ZnO nanostructures, the hydrothermal method is attractive for its simplicity and environment friendly conditions. This review summarizes the conditions leading to the growth of different ZnO nanostructures using hydrothermal technique. Doping of ZnO nanostructures through hydrothermal method are also highlighted.

  19. Quantification of porosity evolution from unaltered to propylitic-altered granites: the 14C-PMMA method applied on the hydrothermal system of Lavras do Sul, Brazil

    Directory of Open Access Journals (Sweden)

    Everton M. Bongiolo

    2007-09-01

    Full Text Available This work is an application of the 14C-Polymethylmethacrylate method to compare the porosity evolution between unaltered and propylitic-altered granites, using samples from Lavras do Sul region, Brazil. This method, when coupled with optical and electronic petrography has the advantage over other methods to provide the quantification and identification of total and local porosity of rocks. From petrographic observations, different kinds of porous zones were identified and quantified (microfractures, grain boundaries, alteration of minerals, etc. Results show that unaltered granites have 0.5 to 0.6% porosity and propylitic-altered ones have 1.7 to 1.8% porosity, even between samples with different textures. Porosity of altered rocks increases mainly due to higher porosity of neoformed chlorite, calcite, sericite and microfractures. Field observations show that later phyllic alteration halos are wider in equigranular than in porphyritic granites, which could not be explained by different original porosity between those rocks. The observed differences of phyllic halos diffusion were controlled by structural and fluid/rock ratio variations between the equigranular and porphyritic granitic facies during the later hydrothermal stage.Este trabalho é uma aplicação do método 14C-polimetilmetacrilato na comparação da evolução da porosidade entre granitos não alterados e propilitizados, utilizando amostras da região de Lavras do Sul, Brasil. Este método, quando associado a análises por petrografia ótica, eletrônica e processamento digital de imagens tem a vantagem de fornecer, além da porosidade total, a quantificação e identificação da porosidade em locais específicos das rochas. A partir da petrografia foi possível identificar e quantificar os diferentes tipos de poros presentes nas rochas (microfraturas, limites de grãos, alteração de minerais, etc. Os resultados mostram que granitos não alterados têm porosidade de 0,5 a 0,6% e

  20. A Facile Method for the Synthesis of 4- Acetylaminobenzo[15]crown-5

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yan-qing; WEI Tai-bao; ZHANG You-ming; ZONG Guo-qiang

    2004-01-01

    The 4-acetylaminobenzo[15]crown-5 is an important intermediate in the synthesis of crown ether cyanine dyes1, in addition, the acetylamino can easily be hydrolyzed to be amine2, to our knowledge which also is an usful intermediate3,4, The classical procedure for the synthesis of 4-acetylaminobenzo[15]crown-5 involves several steps2,5: typically nitration of the benzo[15]crown-5, followed by reduction of the introduced nitro group to form amine, and finally,acylation of the amine to give the amide. In the classical procedure, the reduction of the nitro group is usually proceeded under N2 atmosphere and catalysts such as palladium, Raney Ni are usually employed, which constitute a particular inconvenience.We now report a facile one-pot reaction which can be conducted under mild conditions and avoid the time-consuming nitration step and the inconvenient reduction step.The reaction starts with para-selective C-acylation of the benzo[15]crown-5, which is followed by oxime formation and Beckmann rearrangement in situ. The reaction is proceeded by stirring at moderate temperature, a mixture of polyphosphonic acid, benzo[15]crown-5, glacial acetic acid and hydroxylamine hydrochloride (Scheme I), herein polyphosphonic acid act as catalyst.In conclusion, we have found a facile and convenient method for the synthesis of 4-acetylaminobenzo[15]crown-5, with the advantage of mild conditions, simple operation, short reaction time and less pollution compared with the classical procedure. It is a novel procedure for the synthesis of 4- acetylaminobenzo[15]crown-5.

  1. Future carbon beams at SPIRAL1 facility: Which method is the most efficient?

    Energy Technology Data Exchange (ETDEWEB)

    Maunoury, L., E-mail: maunoury@ganil.fr; Delahaye, P.; Dubois, M.; Dupuis, M.; Frigot, R.; Grinyer, J.; Jardin, P.; Leboucher, C. [GANIL, CEA/CNRS, Bd Henri Becquerel, BP 55027, 14076 Caen Cedex 5 (France); Angot, J.; Lamy, T. [LPSC, Université Joseph Fourier Grenoble 1, Grenoble INP, 53 rue des martyrs, 38026 Grenoble Cedex (France)

    2014-02-15

    Compared to in-flight facilities, Isotope Separator On-Line ones can in principle produce significantly higher radioactive ion beam intensities. On the other hand, they have to cope with delays for the release and ionization which make the production of short-lived isotopes ion beams of reactive and refractory elements particularly difficult. Many efforts are focused on extending the capabilities of ISOL facilities to those challenging beams. In this context, the development of carbon beams is triggering interest [H. Frånberg, M. Ammann, H. W. Gäggeler, and U. Köster, Rev. Sci. Instrum. 77, 03A708 (2006); M. Kronberger, A. Gottberg, T. M. Mendonca, J. P. Ramos, C. Seiffert, P. Suominen, and T. Stora, in Proceedings of the EMIS 2012 [Nucl. Instrum. Methods Phys. Res. B Production of molecular sideband radioisotope beams at CERN-ISOLDE using a Helicon-type plasma ion source (to be published)]: despite its refractory nature, radioactive carbon beams can be produced from molecules (CO or CO{sub 2}), which can subsequently be broken up and multi-ionized to the required charge state in charge breeders or ECR sources. This contribution will present results of experiments conducted at LPSC with the Phoenix charge breeder and at GANIL with the Nanogan ECR ion source for the ionization of carbon beams in the frame of the ENSAR and EMILIE projects. Carbon is to date the lightest condensable element charge bred with an ECR ion source. Charge breeding efficiencies will be compared with those obtained using Nanogan ECRIS and charge breeding times will be presented as well.

  2. Future carbon beams at SPIRAL1 facility: Which method is the most efficient?

    Science.gov (United States)

    Maunoury, L.; Delahaye, P.; Angot, J.; Dubois, M.; Dupuis, M.; Frigot, R.; Grinyer, J.; Jardin, P.; Leboucher, C.; Lamy, T.

    2014-02-01

    Compared to in-flight facilities, Isotope Separator On-Line ones can in principle produce significantly higher radioactive ion beam intensities. On the other hand, they have to cope with delays for the release and ionization which make the production of short-lived isotopes ion beams of reactive and refractory elements particularly difficult. Many efforts are focused on extending the capabilities of ISOL facilities to those challenging beams. In this context, the development of carbon beams is triggering interest [H. Frånberg, M. Ammann, H. W. Gäggeler, and U. Köster, Rev. Sci. Instrum. 77, 03A708 (2006); M. Kronberger, A. Gottberg, T. M. Mendonca, J. P. Ramos, C. Seiffert, P. Suominen, and T. Stora, in Proceedings of the EMIS 2012 [Nucl. Instrum. Methods Phys. Res. B Production of molecular sideband radioisotope beams at CERN-ISOLDE using a Helicon-type plasma ion source (to be published)]: despite its refractory nature, radioactive carbon beams can be produced from molecules (CO or CO2), which can subsequently be broken up and multi-ionized to the required charge state in charge breeders or ECR sources. This contribution will present results of experiments conducted at LPSC with the Phoenix charge breeder and at GANIL with the Nanogan ECR ion source for the ionization of carbon beams in the frame of the ENSAR and EMILIE projects. Carbon is to date the lightest condensable element charge bred with an ECR ion source. Charge breeding efficiencies will be compared with those obtained using Nanogan ECRIS and charge breeding times will be presented as well.

  3. 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.

  4. 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.

  5. 9 CFR 71.7 - Means of conveyance, facilities, premises, and cages and other equipment; methods of cleaning and...

    Science.gov (United States)

    2010-01-01

    ..., premises, and cages and other equipment; methods of cleaning and disinfecting. 71.7 Section 71.7 Animals... TRANSPORTATION OF ANIMALS (INCLUDING POULTRY) AND ANIMAL PRODUCTS GENERAL PROVISIONS § 71.7 Means of conveyance, facilities, premises, and cages and other equipment; methods of cleaning and disinfecting. (a) Railroad cars...

  6. Superhydrophobic hBN-Regulated Sponges with Excellent Absorbency Fabricated Using a Green and Facile Method

    Science.gov (United States)

    Zhou, Ying; Wang, Yao; Liu, Tengfei; Xu, Gang; Chen, Guangming; Li, Huayi; Liu, Lichun; Zhuo, Qiqi; Zhang, Jiaoxia; Yan, Chao

    2017-03-01

    The world faces severe environmental, human and ecological problems when major oil spills and organic discharges are released into the environment. And so it is imperative to develop tools and high performance innovative materials that can efficiently absorb these organic discharges. Furthermore, green, facile methods to produce these advanced materials are also needed. In this paper, we demonstrate a novel porous supersponge based on melamine coated with hBN. This superhydrophobic sponge (with a contact angle >150°) exhibits excellent absorption performance for oils and organic solvents, including good selectivity, high capacity (up to 175 g·g-1) and extraordinary recyclability (less than 20% decline after 30 cycles of absorption/squeezing). The synthetic procedure required only ultrasonication and immersion of the sponge in aqueous hBN solution, being a green, cost-effective and scalable production methodology. By virtue of the straightforward and cost-effective fabrication method, along with the excellent absorption performance, hBN-decorated sponges have great promise for real world practical application in the field of oil spills and organic leakage cleanup.

  7. Methods for characterizing x-ray detectors for use at the National Ignition Facility.

    Science.gov (United States)

    Khan, S F; Benedetti, L R; Hargrove, D R; Glenn, S M; Simanovskaia, N; Holder, J P; Barrios, M A; Hahn, D; Nagel, S R; Bell, P M; Bradley, D K

    2012-10-01

    Gated and streaked x-ray detectors generally require corrections in order to counteract instrumental effects in the data. The method of correcting for gain variations in gated cameras fielded at National Ignition Facility (NIF) is described. Four techniques for characterizing the gated x-ray detectors are described. The current principal method of characterizing x-ray instruments is the production of controlled x-ray emission by laser-generated plasmas as a dedicated shot at the NIF. A recently commissioned pulsed x-ray source has the potential to replace the other characterization systems. This x-ray source features a pulsed power source consisting of a Marx generator, capacitor bank that is charged in series and discharged in parallel, producing up to 300 kV. The pulsed x-ray source initially suffered from a large jitter (∼60 ns), but the recent addition of a pulsed laser to trigger the spark gap has reduced the jitter to ∼5 ns. Initial results show that this tool is a promising alternative to the other flat fielding techniques.

  8. Superhydrophobic hBN-Regulated Sponges with Excellent Absorbency Fabricated Using a Green and Facile Method

    Science.gov (United States)

    Zhou, Ying; Wang, Yao; Liu, Tengfei; Xu, Gang; Chen, Guangming; Li, Huayi; Liu, Lichun; Zhuo, Qiqi; Zhang, Jiaoxia; Yan, Chao

    2017-01-01

    The world faces severe environmental, human and ecological problems when major oil spills and organic discharges are released into the environment. And so it is imperative to develop tools and high performance innovative materials that can efficiently absorb these organic discharges. Furthermore, green, facile methods to produce these advanced materials are also needed. In this paper, we demonstrate a novel porous supersponge based on melamine coated with hBN. This superhydrophobic sponge (with a contact angle >150°) exhibits excellent absorption performance for oils and organic solvents, including good selectivity, high capacity (up to 175 g·g−1) and extraordinary recyclability (less than 20% decline after 30 cycles of absorption/squeezing). The synthetic procedure required only ultrasonication and immersion of the sponge in aqueous hBN solution, being a green, cost-effective and scalable production methodology. By virtue of the straightforward and cost-effective fabrication method, along with the excellent absorption performance, hBN-decorated sponges have great promise for real world practical application in the field of oil spills and organic leakage cleanup. PMID:28332612

  9. A facile and green method towards coal-based fluorescent carbon dots with photocatalytic activity

    Science.gov (United States)

    Hu, Shengliang; Wei, Zhijia; Chang, Qing; Trinchi, Adrian; Yang, Jinlong

    2016-08-01

    One of the most widely used methods for exfoliating crystalline nanocarbon is via strong oxidizing acid treatment of bulk carbon sources, such as graphite, carbon black and coal. Not only is such method dangerous and accompanied by the liberation of toxic gases, it is also plagued by issues of purity, requiring the thorough and costly removal of the excess oxidizing acids and salts formed during the process. Herein we report a facile, green and inexpensive top-down strategy towards fluorescent carbon dots (CDs) from coal without incurring the burden of tedious or inefficient post-processing steps and facing the danger of highly toxic gas liberation. The presented approach shows a high yield and great potential for carbon dot production scale-up using coal, one of our most abundant and low-cost resources. The prepared CDs demonstrate photocatalytic behavior capable of rapidly degrading organic dyes under visible light. Our findings may lead to alternative uses of coal, particularly for applications including the treatment of environmental pollution, solar energy conversion or storage, and highlight coal's applicability in areas other than energy producing via burning of this great resource.

  10. Facile time-of-flight methods for characterizing pulsed superfluid helium droplet beams

    Energy Technology Data Exchange (ETDEWEB)

    He, Yunteng; Zhang, Jie; Li, Yang; Freund, William M.; Kong, Wei, E-mail: wei.kong@oregonstate.edu [Department of Chemistry, Oregon State University, Corvallis, Oregon 97331 (United States)

    2015-08-15

    We present two facile time-of-flight (TOF) methods of detecting superfluid helium droplets and droplets with neutral dopants. Without an electron gun and with only a heated filament and pulsed electrodes, the electron impact ionization TOF mass spectrometer can resolve ionized helium clusters such as He{sub 2}{sup +} and He{sub 4}{sup +}, which are signatures of superfluid helium droplets. Without ionizing any helium atoms, multiphoton non-resonant laser ionization of CCl{sub 4} doped in superfluid helium droplets at 266 nm generates complex cluster ions of dopant fragments with helium atoms, including (He){sub n}C{sup +}, (He){sub n}Cl{sup +}, and (He){sub n}CCl{sup +}. Using both methods, we have characterized our cryogenic pulsed valve—the Even-Lavie valve. We have observed a primary pulse with larger helium droplets traveling at a slower speed and a rebound pulse with smaller droplets at a faster speed. In addition, the pickup efficiency of dopant is higher for the primary pulse when the nozzle temperature is higher than 13 K, and the total time duration of the doped droplet pulse is only on the order of 20 μs. These results stress the importance of fast and easy characterization of the droplet beam for sensitive measurements such as electron diffraction of doped droplets.

  11. Facile time-of-flight methods for characterizing pulsed superfluid helium droplet beams.

    Science.gov (United States)

    He, Yunteng; Zhang, Jie; Li, Yang; Freund, William M; Kong, Wei

    2015-08-01

    We present two facile time-of-flight (TOF) methods of detecting superfluid helium droplets and droplets with neutral dopants. Without an electron gun and with only a heated filament and pulsed electrodes, the electron impact ionization TOF mass spectrometer can resolve ionized helium clusters such as He2(+) and He4(+), which are signatures of superfluid helium droplets. Without ionizing any helium atoms, multiphoton non-resonant laser ionization of CCl4 doped in superfluid helium droplets at 266 nm generates complex cluster ions of dopant fragments with helium atoms, including (He)(n)C(+), (He)(n)Cl(+), and (He)(n)CCl(+). Using both methods, we have characterized our cryogenic pulsed valve—the Even-Lavie valve. We have observed a primary pulse with larger helium droplets traveling at a slower speed and a rebound pulse with smaller droplets at a faster speed. In addition, the pickup efficiency of dopant is higher for the primary pulse when the nozzle temperature is higher than 13 K, and the total time duration of the doped droplet pulse is only on the order of 20 μs. These results stress the importance of fast and easy characterization of the droplet beam for sensitive measurements such as electron diffraction of doped droplets.

  12. Development of a facile method for high throughput screening with reporter gene assays.

    Science.gov (United States)

    Goetz, A S; Andrews, J L; Littleton, T R; Ignar, D M

    2000-10-01

    This report describes a facile methodology for high throughput screening with stable mammalian cell reporter gene assays. We have adapted a 96-well adherent cell method to an assay in which cells propagated in suspension are dispensed into 96- or 384-well plates containing test compounds in 100% DMSO. The validation of a stable CHO cell line that expresses 6xCRE-luciferase for use as a reporter gene host cell line is described. The reporter gene, when expressed in this particular CHO cell line, appears to respond specifically to modulation of cAMP levels, thus the cell line is appropriate for screening and pharmacological analysis of Galpha(s)- and Galpha(i)-coupled seven-transmembrane receptors. The development of the new suspension cell assay in both 96- and 384-well formats was performed using a derivative of the CHO host reporter cell line that was stably transfected with human melanocortin-1 receptor. The response of this cell line to NDP-alpha-melanocyte-stimulating hormone and forskolin was nearly identical between the adherent and suspension methods. The new method offers improvements in cost, throughput, cell culture effort, compound stability, accuracy of compound delivery, and hands-on time. The 384-well assay can be performed at high capacity in any laboratory without the use of expensive automation systems such that a single person can screen 100 plates per day with 3.5-4 h hands-on time. Although the system has been validated using Galpha(s)-coupled receptor-mediated activation of a cAMP response element, the method can be applied to other types of targets and/or transcriptional response elements.

  13. A facile method to prepare superparamagnetic iron oxide and hydrophobic drug-encapsulated biodegradable polyurethane nanoparticles.

    Science.gov (United States)

    Cheng, Kuo-Wei; Hsu, Shan-Hui

    2017-01-01

    Superparamagnetic iron oxide nanoparticles (SPIO NPs) have a wide range of biomedical applications such as in magnetic resonance imaging, targeting, and hyperthermia therapy. Aggregation of SPIO NPs can occur because of the hydrophobic surface and high surface energy of SPIO NPs. Here, we developed a facile method to encapsulate SPIO NPs in amphiphilic biodegradable polymer. Anionic biodegradable polyurethane nanoparticles (PU NPs) with ~35 nm size and different chemistry were prepared by waterborne processes. SPIO NPs were synthesized by chemical co-precipitation. SPIO NPs were then added to the aqueous dispersion of PU NPs, followed by application of high-frequency (~20 kHz) ultrasonic vibration for 3 min. This method rendered SPIO-PU hybrid NPs (size ~110 nm) suspended in water. SPIO-PU hybrid NPs contained ~50-60 wt% SPIO and retained the superparamagnetic property (evaluated by a magnetometer) as well as high contrast in magnetic resonance imaging. SPIO-PU NPs also showed the ability to provide cell hyperthermic treatment. Using the same ultrasonic method, hydrophobic drug (Vitamin K3 [VK3]) or (9-(methylaminomethyl) anthracene [MAMA]) could also be encapsulated in PU NPs. The VK3-PU or MAMA-PU hybrid NPs had ~35 nm size and different release profiles for PUs with different chemistry. The encapsulation efficiency for VK3 and MAMA was high (~95%) without burst release. The encapsulation mechanism may be attributed to the low glass transition temperature (Tg) and good mechanical compliance of PU NPs. The new encapsulation method involving waterborne biodegradable PU NPs is simple, rapid, and effective to produce multimodular NP carriers.

  14. A facile method to prepare superparamagnetic iron oxide and hydrophobic drug-encapsulated biodegradable polyurethane nanoparticles

    Directory of Open Access Journals (Sweden)

    Cheng K

    2017-03-01

    Full Text Available Kuo-Wei Cheng, Shan-hui Hsu Institute of Polymer Science and Engineering, College of Engineering, National Taiwan University, Taipei, Taiwan, Republic of China Abstract: Superparamagnetic iron oxide nanoparticles (SPIO NPs have a wide range of biomedical applications such as in magnetic resonance imaging, targeting, and hyperthermia therapy. Aggregation of SPIO NPs can occur because of the hydrophobic surface and high surface energy of SPIO NPs. Here, we developed a facile method to encapsulate SPIO NPs in amphiphilic biodegradable polymer. Anionic biodegradable polyurethane nanoparticles (PU NPs with ~35 nm size and different chemistry were prepared by waterborne processes. SPIO NPs were synthesized by chemical co-precipitation. SPIO NPs were then added to the aqueous dispersion of PU NPs, followed by application of high-frequency (~20 kHz ultrasonic vibration for 3 min. This method rendered SPIO-PU hybrid NPs (size ~110 nm suspended in water. SPIO-PU hybrid NPs contained ~50–60 wt% SPIO and retained the superparamagnetic property (evaluated by a magnetometer as well as high contrast in magnetic resonance imaging. SPIO-PU NPs also showed the ability to provide cell hyperthermic treatment. Using the same ultrasonic method, hydrophobic drug (Vitamin K3 [VK3] or (9-(methylaminomethylanthracene [MAMA] could also be encapsulated in PU NPs. The VK3-PU or MAMA-PU hybrid NPs had ~35 nm size and different release profiles for PUs with different chemistry. The encapsulation efficiency for VK3 and MAMA was high (~95% without burst release. The encapsulation mechanism may be attributed to the low glass transition temperature (Tg and good mechanical compliance of PU NPs. The new encapsulation method involving waterborne biodegradable PU NPs is simple, rapid, and effective to produce multimodular NP carriers. Keywords: superparamagnetic iron oxide, polyurethane, drug release, hybrid nanoparticles

  15. A facile method to prepare superparamagnetic iron oxide and hydrophobic drug-encapsulated biodegradable polyurethane nanoparticles

    Science.gov (United States)

    Cheng, Kuo-Wei; Hsu, Shan-hui

    2017-01-01

    Superparamagnetic iron oxide nanoparticles (SPIO NPs) have a wide range of biomedical applications such as in magnetic resonance imaging, targeting, and hyperthermia therapy. Aggregation of SPIO NPs can occur because of the hydrophobic surface and high surface energy of SPIO NPs. Here, we developed a facile method to encapsulate SPIO NPs in amphiphilic biodegradable polymer. Anionic biodegradable polyurethane nanoparticles (PU NPs) with ~35 nm size and different chemistry were prepared by waterborne processes. SPIO NPs were synthesized by chemical co-precipitation. SPIO NPs were then added to the aqueous dispersion of PU NPs, followed by application of high-frequency (~20 kHz) ultrasonic vibration for 3 min. This method rendered SPIO-PU hybrid NPs (size ~110 nm) suspended in water. SPIO-PU hybrid NPs contained ~50–60 wt% SPIO and retained the superparamagnetic property (evaluated by a magnetometer) as well as high contrast in magnetic resonance imaging. SPIO-PU NPs also showed the ability to provide cell hyperthermic treatment. Using the same ultrasonic method, hydrophobic drug (Vitamin K3 [VK3]) or (9-(methylaminomethyl) anthracene [MAMA]) could also be encapsulated in PU NPs. The VK3-PU or MAMA-PU hybrid NPs had ~35 nm size and different release profiles for PUs with different chemistry. The encapsulation efficiency for VK3 and MAMA was high (~95%) without burst release. The encapsulation mechanism may be attributed to the low glass transition temperature (Tg) and good mechanical compliance of PU NPs. The new encapsulation method involving waterborne biodegradable PU NPs is simple, rapid, and effective to produce multimodular NP carriers. PMID:28280341

  16. Evaluation of Legionella Air Contamination in Healthcare Facilities by Different Sampling Methods: An Italian Multicenter Study.

    Science.gov (United States)

    Montagna, Maria Teresa; De Giglio, Osvalda; Cristina, Maria Luisa; Napoli, Christian; Pacifico, Claudia; Agodi, Antonella; Baldovin, Tatjana; Casini, Beatrice; Coniglio, Maria Anna; D'Errico, Marcello Mario; Delia, Santi Antonino; Deriu, Maria Grazia; Guida, Marco; Laganà, Pasqualina; Liguori, Giorgio; Moro, Matteo; Mura, Ida; Pennino, Francesca; Privitera, Gaetano; Romano Spica, Vincenzo; Sembeni, Silvia; Spagnolo, Anna Maria; Tardivo, Stefano; Torre, Ida; Valeriani, Federica; Albertini, Roberto; Pasquarella, Cesira

    2017-06-22

    Healthcare facilities (HF) represent an at-risk environment for legionellosis transmission occurring after inhalation of contaminated aerosols. In general, the control of water is preferred to that of air because, to date, there are no standardized sampling protocols. Legionella air contamination was investigated in the bathrooms of 11 HF by active sampling (Surface Air System and Coriolis(®)μ) and passive sampling using settling plates. During the 8-hour sampling, hot tap water was sampled three times. All air samples were evaluated using culture-based methods, whereas liquid samples collected using the Coriolis(®)μ were also analyzed by real-time PCR. Legionella presence in the air and water was then compared by sequence-based typing (SBT) methods. Air contamination was found in four HF (36.4%) by at least one of the culturable methods. The culturable investigation by Coriolis(®)μ did not yield Legionella in any enrolled HF. However, molecular investigation using Coriolis(®)μ resulted in eight HF testing positive for Legionella in the air. Comparison of Legionella air and water contamination indicated that Legionella water concentration could be predictive of its presence in the air. Furthermore, a molecular study of 12 L. pneumophila strains confirmed a match between the Legionella strains from air and water samples by SBT for three out of four HF that tested positive for Legionella by at least one of the culturable methods. Overall, our study shows that Legionella air detection cannot replace water sampling because the absence of microorganisms from the air does not necessarily represent their absence from water; nevertheless, air sampling may provide useful information for risk assessment. The liquid impingement technique appears to have the greatest capacity for collecting airborne Legionella if combined with molecular investigations.

  17. High activity of Ag-doped Cd0.1Zn0.9S photocatalyst prepared by the hydrothermal method for hydrogen production under visible-light irradiation

    Directory of Open Access Journals (Sweden)

    Leny Yuliati

    2014-05-01

    Full Text Available Background: The hydrothermal method was used as a new approach to prepare a series of Ag-doped Cd0.1Zn0.9S photocatalysts. The effect of Ag doping on the properties and photocatalytic activity of Cd0.1Zn0.9S was studied for the hydrogen production from water reduction under visible light irradiation.Results: Compared to the series prepared by the co-precipitation method, samples prepared by the hydrothermal method performed with a better photocatalytic activity. The sample with the optimum amount of Ag doping showed the highest hydrogen production rate of 3.91 mmol/h, which was 1.7 times higher than that of undoped Cd0.1Zn0.9S. With the Ag doping, a red shift in the optical response was observed, leading to a larger portion of the visible light absorption than that of without doping. In addition to the larger absorption in the visible-light region, the increase in photocatalytic activity of samples with Ag doping may also come from the Ag species facilitating electron–hole separation.Conclusion: This study demonstrated that Ag doping is a promising way to enhance the activity of Cd0.1Zn0.9S photocatalyst.

  18. A method for comparison testing of window accessories: The AMSCO thermal test facility

    Energy Technology Data Exchange (ETDEWEB)

    Lexen, T.C.; Muldary, P.F.

    1985-01-01

    A test facility has been developed for the comparison of the thermal performance of window accessories. The facility is presented as a developmental tool, allowing direct comparison testing of prototypes and new products, under controlled interior and real weather conditions. Nighttime U-value testing is emphasized; testing options and limitations are discussed, along with future plans.

  19. A facile method to fabricate hydrogels with microchannel-like porosity for tissue engineering.

    Science.gov (United States)

    Hammer, Joshua; Han, Li-Hsin; Tong, Xinming; Yang, Fan

    2014-02-01

    Hydrogels are widely used as three-dimensional (3D) tissue engineering scaffolds due to their tissue-like water content, as well as their tunable physical and chemical properties. Hydrogel-based scaffolds are generally associated with nanoscale porosity, whereas macroporosity is highly desirable to facilitate nutrient transfer, vascularization, cell proliferation and matrix deposition. Diverse techniques have been developed for introducing macroporosity into hydrogel-based scaffolds. However, most of these methods involve harsh fabrication conditions that are not cell friendly, result in spherical pore structure, and are not amenable for dynamic pore formation. Human tissues contain abundant microchannel-like structures, such as microvascular network and nerve bundles, yet fabricating hydrogels containing microchannel-like pore structures remains a great challenge. To overcome these limitations, here we aim to develop a facile, cell-friendly method for engineering hydrogels with microchannel-like porosity using stimuli-responsive microfibers as porogens. Microfibers with sizes ranging 150-200 μm were fabricated using a coaxial flow of alginate and calcium chloride solution. Microfibers containing human embryonic kidney (HEK) cells were encapsulated within a 3D gelatin hydrogel, and then exposed to ethylenediaminetetraacetic acid (EDTA) solution at varying doses and duration. Scanning electron microscopy confirmed effective dissolution of alginate microfibers after EDTA treatment, leaving well-defined, interconnected microchannel structures within the 3D hydrogels. Upon release from the alginate fibers, HEK cells showed high viability and enhanced colony formation along the luminal surfaces of the microchannels. In contrast, HEK cells in non-EDTA treated control exhibited isolated cells, which remained entrapped in alginate microfibers. Together, our results showed a facile, cell-friendly process for dynamic microchannel formation within hydrogels, which may

  20. Evaluation of environmental sampling methods and rapid detection assays for recovery and identification of Listeria spp. from meat processing facilities.

    Science.gov (United States)

    Kovacević, Jovana; Bohaychuk, Valerie M; Barrios, Pablo Romero; Gensler, Gary E; Rolheiser, Deana L; McMullen, Lynn M

    2009-04-01

    Studies that isolated Listeria spp. from the environment of two meat processing facilities were conducted. Samples were collected in the processing environment of the facilities with three different sampling methods (cotton swab, sterile sponge, and composite-ply tissues) to evaluate their ability to recover Listeria spp. A total of 240 samples for each sampling method were collected and tested. The cotton swab method of sampling was significantly (P 0.05) in their ability to recover Listeria spp. The specificity and sensitivity of four detection methods (conventional culture, Petrifilm Environmental Listeria Plates [ELP], lateral-flow immunoprecipitation [LFI], and automated PCR) were evaluated for identification of Listeria spp. Facilities were visited until a minimum of 100 positive and 100 negative samples per detection method were collected. The LFI and PCR methods were highly sensitive (95.5 and 99.1%, respectively) and specific (100%) relative to the culture method. The ELP method was significantly less efficient (P < 0.01) than LFI and PCR in detection of Listeria spp., with lower sensitivity (50.6%) and specificity (91.5%). Kappa values indicated excellent agreement of the LFI and PCR assays and moderate agreement of the ELP method to the culture method. Overall, ELP was easy to use but less efficient in detection of Listeria spp. from environmental samples, while the LFI and PCR methods were found to be excellent alternatives to culture, considering performance and time and labor inputs.

  1. 水热法合成钛酸盐(MTiO3)超细粉体%Preparation of Ultrafine Titanates Powder by Hydrothermal Method

    Institute of Scientific and Technical Information of China (English)

    刘春英; 柳云骐; 安长华; 王淑涛; 薛颖

    2011-01-01

    The ultrafine titanates (BaTiO3, PbTiO3, SrTiO3 ) powder was prepared under milder hydrothermal method condition in this paper. Uing Ba (OH)2 and Ti ( OC4 H9 )4 as raw materrials, the cubic BaTiO3 powder with 20-80 nm was prepared at 150℃ for 48 h; the tetragonal BaTiO3 powder with 50-80 nm particle size was prepared at 180℃ for 48 h with high NH3 · H2O concentrations. Uing Pb (CH3COO)2 and Ti(OC4H9)4 as raw materials, the tetragonal PbTiO3 powder with 100-130 nm was prepared at 180℃ for 20 h with 1.0 mol/L NaOH. Using Sr( NO3 )2 and Ti (OC4H9 )4 as raw materials,the SrTiO3 powder with 40-90 nm was prepared at 180℃ for 2 h with 0.2 mol/L KOH. The well dispersed, uniform and pure powers of titanates were obtained.%本文采用水热法在温和条件下制备出钛酸盐(BaTiO3、PbTiO3、SrTiO3)超细粉体.以Ba(OH)2和钛酸四丁酯为原料,强碱性条件下,水热反应温度150℃、48 h时制备出粒径为20~80 nm的立方相BaTiO3;反应温度为180℃、48 h时制备出粒径为50~80 nm的四方相BaTiO3.以钛酸四丁酯和醋酸铅为原料,在180℃、20h条件下,碱度为c(NaOH)=1.O mol/L时,制备出粒径在100~130 nm之间的四方相PbTiO3粉体.以钛酸四丁酯和硝酸锶为原料,在180℃、2 h条件下,碱度为c(KOH)=0.2 mol/L时,制备的SrTiO3粉体粒径在40~90nm之间.通过控制反应条件制得的钛酸盐粉体分散性好、均匀、纯度高.

  2. A method for studying the development pattern of urban commercial service facilities based on customer reviews from social media

    Directory of Open Access Journals (Sweden)

    Y. D. Wang

    2016-06-01

    Full Text Available Urbanization is one of the most important human social activities in the 21st century (Chaolin et al., 2012. With an increasing number of people visiting cities, the provision of adequate urban service facilities, including public and commercial service facilities, in locations where people live has become an important guarantee of the success of urbanization. Exploring the commercial service facilities in a specific area of a city can help us understand the progress and trends of urban renewal in the area, provide a quantitative basis for evaluating the rationality of planning implementation, and facilitate an analysis of the effects of different factors on the regional development of a city (Schor et al. 2003. In this paper, we proposed a data processing and analysis method for studying the distribution and development pattern of urban commercial facilities based on customer reviews. In addition, based on road network constraints, we explored the patterns contained in customer reviews data, including patterns for the spatial distribution and spatial-temporal evolution of facilities as well as the number of facilities and degree of satisfaction.

  3. A method for studying the development pattern of urban commercial service facilities based on customer reviews from social media

    Science.gov (United States)

    Wang, Y. D.; Jiang, B. T.; Ye, X. Y.

    2016-06-01

    Urbanization is one of the most important human social activities in the 21st century (Chaolin et al., 2012). With an increasing number of people visiting cities, the provision of adequate urban service facilities, including public and commercial service facilities, in locations where people live has become an important guarantee of the success of urbanization. Exploring the commercial service facilities in a specific area of a city can help us understand the progress and trends of urban renewal in the area, provide a quantitative basis for evaluating the rationality of planning implementation, and facilitate an analysis of the effects of different factors on the regional development of a city (Schor et al. 2003). In this paper, we proposed a data processing and analysis method for studying the distribution and development pattern of urban commercial facilities based on customer reviews. In addition, based on road network constraints, we explored the patterns contained in customer reviews data, including patterns for the spatial distribution and spatial-temporal evolution of facilities as well as the number of facilities and degree of satisfaction.

  4. Characterization and Photocatalytic Activity ofMixed Nanocrystalline TiO2 Powders Prepared by Xerogel-Hydrothermal Method in Different Acid Solutions

    Institute of Scientific and Technical Information of China (English)

    刘翠萍; 于涛; 谭欣

    2016-01-01

    TiO2 nanoparticles(NPs)were prepared via the hydrothermal route of TiO2 xerogel in nitric acid, hy-drochloric acid and acetic acid. The physico-chemical properties of the powders were characterized by X-ray dif-fraction(XRD)and N2 adsorption desorption techniques. The effects of the different acids on the structure(crystal phase)and texture(primary particle size and porosity)of the TiO2 powders were explored. Results indicated that acetic acid facilitated the formation and stability of pure anatase phase. On the other hand, nitric acid and hydro-chloric acid led to the transformation from anatase to rutile. The catalyst synthesized via the hydrothermal route of TiO2 xerogel in the low concentration hydrochloric acid solution(Ti-HCl-0.15)had the highest photocatalytic activ-ity than the catalysts obtained in the other two acid solutions. The effects of the different acids were discussed in terms of acid strength, chelating effect and the thermal stability of the adsorbed acidic anions.

  5. ZnO-doped LiFePO{sub 4} cathode material for lithium-ion battery fabricated by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Yemin, E-mail: huyemin@shu.edu.cn [Laboratory for Microstructures/School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Yao, Jun; Zhao, Zhe; Zhu, Mingyuan; Ying Li,; Jin, Hongming [Laboratory for Microstructures/School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Zhao, Huijun [Centre for Clean Environment and Energy, Griffith School of Environment, Griffith University, Queensland 4222 (Australia); Wang, Jiazhao [Institute for Superconducting and Electronic Materials, Innovation Campus, University of Wollongong, NSW 2500 (Australia)

    2013-09-16

    LiFePO{sub 4} particles doped with zinc oxide was synthesized via a hydrothermal route and used as cathode material for lithium-ion battery. Sample of preferable shape and structure was obtained by a concise and efficient process. ZnO doping into the LiFePO{sub 4} matrix was positively confirmed by the results of X-ray diffraction (XRD); high-resolution transmission electron microscopy (HRTEM); energy dispersive spectrometer (EDS), and X-ray photoelectron spectroscopy (XPS). LiFePO{sub 4} doped with ZnO tends to form nanometer-size and homogeneous particles, which can improve markedly the performance and stability of charge-discharge cycle. A specific discharge capacity of ZnO-doped LiFePO{sub 4} at 132.3 mAh g{sup −1} was achieved, with 1.8% decrease after 100 cycles. Based on the cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) results, it has further shown that ZnO doping effectively reduces the impacts of polarization and transfer resistance during electrochemical processes. - Highlights: • Zinc source is added into LiFePO{sub 4} precursor in the form of Zn(OH){sub 2} solution. • ZnO help LiFePO{sub 4} form fine and even particles in the hydrothermal condition. • ZnO particles and Zn{sup 2+} ions act on the electrochemical performance of LiFePO{sub 4} together.

  6. Fault detection and analysis in nuclear research facility using artificial intelligence methods

    Energy Technology Data Exchange (ETDEWEB)

    Ghazali, Abu Bakar, E-mail: Abakar@uniten.edu.my [Department of Electronics & Communication, College of Engineering, Universiti Tenaga Nasional, 43009 Kajang, Selangor (Malaysia); Ibrahim, Maslina Mohd [Instrumentation Program, Malaysian Nuclear Agency, Bangi (Malaysia)

    2016-01-22

    In this article, an online detection of transducer and actuator condition is discussed. A case study is on the reading of area radiation monitor (ARM) installed at the chimney of PUSPATI TRIGA nuclear reactor building, located at Bangi, Malaysia. There are at least five categories of abnormal ARM reading that could happen during the transducer failure, namely either the reading becomes very high, or very low/ zero, or with high fluctuation and noise. Moreover, the reading may be significantly higher or significantly lower as compared to the normal reading. An artificial neural network (ANN) and adaptive neuro-fuzzy inference system (ANFIS) are good methods for modeling this plant dynamics. The failure of equipment is based on ARM reading so it is then to compare with the estimated ARM data from ANN/ ANFIS function. The failure categories in either ‘yes’ or ‘no’ state are obtained from a comparison between the actual online data and the estimated output from ANN/ ANFIS function. It is found that this system design can correctly report the condition of ARM equipment in a simulated environment and later be implemented for online monitoring. This approach can also be extended to other transducers, such as the temperature profile of reactor core and also to include other critical actuator conditions such as the valves and pumps in the reactor facility provided that the failure symptoms are clearly defined.

  7. A facile method to compare EFTEM maps obtained from materials changing composition over time

    KAUST Repository

    Casu, Alberto

    2015-10-31

    Energy Filtered Transmission Electron Microscopy (EFTEM) is an analytical tool that has been successfully and widely employed in the last two decades for obtaining fast elemental maps in TEM mode. Several studies and efforts have been addressed to investigate limitations and advantages of such technique, as well as to improve the spatial resolution of compositional maps. Usually, EFTEM maps undergo post-acquisition treatments by changing brightness and contrast levels, either via dedicated software or via human elaboration, in order to maximize their signal-to-noise ratio and render them as visible as possible. However, elemental maps forming a single set of EFTEM images are usually subjected to independent map-by-map image treatment. This post-acquisition step becomes crucial when analyzing materials that change composition over time as a consequence of an external stimulus, because the map-by-map approach doesn\\'t take into account how the chemical features of the imaged materials actually progress, in particular when the investigated elements exhibit very low signals. In this article, we present a facile procedure applicable to whole sets of EFTEM maps acquired on a sample that is evolving over time. The main aim is to find a common method to treat the images features, in order to make them as comparable as possible without affecting the information there contained. Microsc. Res. Tech. 78:1090–1097, 2015. © 2015 Wiley Periodicals, Inc.

  8. Size-controlled fluorescent nanodiamonds: a facile method of fabrication and color-center counting.

    Science.gov (United States)

    Mahfouz, Remi; Floyd, Daniel L; Peng, Wei; Choy, Jennifer T; Loncar, Marko; Bakr, Osman M

    2013-12-07

    We present a facile method for the production of fluorescent diamond nanocrystals (DNCs) of different sizes and efficiently quantify the concentration of emitting defect color centers (DCCs) of each DNC size. We prepared the DNCs by ball-milling commercially available micrometer-sized synthetic (high pressure, high temperature (HPHT)) diamonds and then separated the as-produced DNCs by density gradient ultracentrifugation (DGU) into size-controlled fractions. A protocol to enhance the uniformity of the nitrogen-vacancy (NV) centers in the diamonds was devised by depositing the DNCs as a dense monolayer on amino-silanized silicon substrates and then subjecting the monolayer to He(+) beam irradiation. Using a standard confocal setup, we analyzed the average number of NV centers per crystal, and obtained a quantitative relationship between the DNC particle size and the NV number per crystal. This relationship was in good agreement with results from previous studies that used more elaborate setups. Our findings suggest that nanocrystal size separation by DGU may be used to control the number of defects per nanocrystal. The efficient approaches described herein to control and quantify DCCs are valuable to researchers as they explore applications for color centers and new strategies to create them.

  9. Size-controlled fluorescent nanodiamonds: a facile method of fabrication and color-center counting

    Science.gov (United States)

    Mahfouz, Remi; Floyd, Daniel L.; Peng, Wei; Choy, Jennifer T.; Loncar, Marko; Bakr, Osman M.

    2013-11-01

    We present a facile method for the production of fluorescent diamond nanocrystals (DNCs) of different sizes and efficiently quantify the concentration of emitting defect color centers (DCCs) of each DNC size. We prepared the DNCs by ball-milling commercially available micrometer-sized synthetic (high pressure, high temperature (HPHT)) diamonds and then separated the as-produced DNCs by density gradient ultracentrifugation (DGU) into size-controlled fractions. A protocol to enhance the uniformity of the nitrogen-vacancy (NV) centers in the diamonds was devised by depositing the DNCs as a dense monolayer on amino-silanized silicon substrates and then subjecting the monolayer to He+ beam irradiation. Using a standard confocal setup, we analyzed the average number of NV centers per crystal, and obtained a quantitative relationship between the DNC particle size and the NV number per crystal. This relationship was in good agreement with results from previous studies that used more elaborate setups. Our findings suggest that nanocrystal size separation by DGU may be used to control the number of defects per nanocrystal. The efficient approaches described herein to control and quantify DCCs are valuable to researchers as they explore applications for color centers and new strategies to create them.

  10. A Facile Method for Preparing Transparent, Conductive, and Paper-Like Silver Nanowire Films

    Directory of Open Access Journals (Sweden)

    Yajie Wang

    2011-01-01

    Full Text Available Transparent, conductive, and flexible silver nanowire (AgNW films have been fabricated by a facile two-step method. Firstly, the well-dispersed AgNW suspension is vacuum filtered using mixed esters of cellulose (MCE membranes as filters. Then, the AgNW-MCE films are treated with acetone vapor. After the infiltration of acetone vapor, the white and porous MCE membranes change into transparent and pore-free, and AgNW-MCE films are obtained with extraordinary optical, conductive, and mechanical properties. An optimal result is obtained with transmittance of 85% at 550 nm and sheet resistance about 50 Ohm/sq. The flexibility of AgNW-MCE films is remarkable, which is comparable to that of the AgNW film on flexible polyethylene terephthalate (PET. More important, AgNW-MCE films show an excellent adhesion to the substrate, which causes a stable electrical conductivity even after scotch tape test and finger friction test. As a result of improved adhesion to the substrate, the sheet resistance of AgNW-MCE films is about 20% smaller than that of AgNW-PET films.

  11. A facile method for preparation superhydrophobic paper with enhanced physical strength and moisture-proofing property.

    Science.gov (United States)

    Li, Hui; Yang, Jin; Li, Pan; Lan, Tianqing; Peng, Lincai

    2017-03-15

    We proposed a green and facile method to fabricate superhydrophobic paper in this study, which is layer-by-layer (LBL) deposition of TiO2 nanoparticles/sodium alginate (ALG) multilayers on paper surface followed by an adsorption treatment of colloidal carnauba wax. The formation of TiO2/ALG multilayers on paper surface was characterized by X-ray photoelectron spectroscopy (XPS), zeta potential measurement, scanning electron microscopy (SEM) and atomic force microscopy (AFM), respectively. The wetting property of modified paper was investigated by water contact angle (WCA) measurement. Moreover, the modified paper tensile strength has been evaluated. The results showed that WCA of paper modified with a wax-treated (TiO2/ALG)3.5 multilayer reached up to 151.5°, and this obtained superhydrophobic paper exhibited improved tensile strength (increased by 4.1% compared to the pristine paper), excellent moisture-proofing property and high strength stability under high relative humidity condition, which might has a great potential for use in the liquid paper packaging and moisture-proof paper packaging.

  12. A facile method for fabricating TiO2@mesoporous carbon and three-layered nanocomposites

    Science.gov (United States)

    Liu, Yong; Jin, Haibao; Zhu, Shenmin; Liu, Yunchun; Long, Mingce; Zhou, Yongfeng; Yan, Deyue

    2012-08-01

    Herein, we report a new and facile method for fabricating TiO2@mesoporous carbon hybrid materials. Uniform polydopamine (PDA) layers were coated onto the surface of titanate nanotubes (TNTs) and TiO2 nanorods (TNDs) through the spontaneous adhesion and self-polymerization of dopamine during the dipping process. Core-shell mesoporous carbon nanotubes with TiO2 nanorods or nanoparticles encapsulated inside (TiO2@MC) were then obtained by transforming PDA layers into carbonaceous ones through calcination in nitrogen at 800 °C. The thickness of the mesoporous carbon layers is tens of nanometers and can be controlled by adjusting the coated PDA layers through the self-polymerization reaction time. In addition, three-layered nanocomposites of TiO2@MC@MO (MO, metal oxide) can be readily prepared by utilizing PDA layers in TNTs@PDA or TNDs@PDA to adsorb the metal ions, followed by the calcination process.

  13. Iron pyrite: Phase and shape control by facile hot injection method

    Science.gov (United States)

    Trinh, Thanh Kieu; Pham, Viet Thanh Hau; Truong, Nguyen Tam Nguyen; Kim, Chang Duk; Park, Chinho

    2017-03-01

    Pure phases of cubic and spherical FeS2 nanocrystals (NCs) with the mean size of 80 nm and 30 nm, respectively, were obtained using trioctylamine and oleylamine as the solvents to dissolve the sulfur source via a facile and efficient hot injection method. The pure phase formation and shape control were strongly dependent on the concentration of active sulfur source (H2S) that could be formed by the reaction between the elemental sulfur and a primary amine. The chemically active sulfur source could facilitate the formation of a pure FeS2 phase from a FeS phase via a Fe3S4 phase. In addition, the active sulfur concentration is believed to be the main factor to drive the orientation attachment to obtain different shapes of FeS2 NCs. The obtained FeS2 pyrite NCs with excellent phase purity and good optical properties are believed to have potential applications to various energy devices including low-cost photovoltaics.

  14. Size-controlled fluorescent nanodiamonds: A facile method of fabrication and color-center counting

    KAUST Repository

    Mahfouz, Remi

    2013-01-01

    We present a facile method for the production of fluorescent diamond nanocrystals (DNCs) of different sizes and efficiently quantify the concentration of emitting defect color centers (DCCs) of each DNC size. We prepared the DNCs by ball-milling commercially available micrometer-sized synthetic (high pressure, high temperature (HPHT)) diamonds and then separated the as-produced DNCs by density gradient ultracentrifugation (DGU) into size-controlled fractions. A protocol to enhance the uniformity of the nitrogen-vacancy (NV) centers in the diamonds was devised by depositing the DNCs as a dense monolayer on amino-silanized silicon substrates and then subjecting the monolayer to He+ beam irradiation. Using a standard confocal setup, we analyzed the average number of NV centers per crystal, and obtained a quantitative relationship between the DNC particle size and the NV number per crystal. This relationship was in good agreement with results from previous studies that used more elaborate setups. Our findings suggest that nanocrystal size separation by DGU may be used to control the number of defects per nanocrystal. The efficient approaches described herein to control and quantify DCCs are valuable to researchers as they explore applications for color centers and new strategies to create them. © 2013 The Royal Society of Chemistry.

  15. 237 Np analytical method using 239 Np tracers and application to a contaminated nuclear disposal facility

    Energy Technology Data Exchange (ETDEWEB)

    Snow, Mathew S.; Morrison, Samuel S.; Clark, Sue B.; Olson, John E.; Watrous, Matthew G.

    2017-06-01

    Environmental 237Np analyses are challenged by low 237Np concentrations and lack of an available yield tracer; we report a rapid, inexpensive 237Np analytical approach employing the short lived 239Np (t1/2 = 2.3 days) as a chemical yield tracer followed by 237Np quantification using inductively coupled plasma-mass spectrometry. 239Np tracer is obtained via separation from a 243Am stock solution and standardized using gamma spectrometry immediately prior to sample processing. Rapid digestions using a commercial, 900 watt “Walmart” microwave and Parr microwave vessels result in 99.8 ± 0.1% digestion yields, while chromatographic separations enable Np/U separation factors on the order of 106 and total Np yields of 95 ± 4% (2σ). Application of this method to legacy soil samples surrounding a radioactive disposal facility (the Subsurface Disposal Area at Idaho National Laboratory) reveal the presence of low level 237Np contamination within 600 meters of this site, with maximum 237Np concentrations on the order of 103 times greater than nuclear weapons testing fallout levels.

  16. A facile method for electrospinning of Ag nanoparticles/poly (vinyl alcohol)/carboxymethyl-chitosan nanofibers

    Science.gov (United States)

    Zhao, Yinghui; Zhou, Ying; Wu, Xiaomian; Wang, Lu; Xu, Ling; Wei, Shicheng

    2012-09-01

    A facile method to prepare silver nanoparticles (AgNPs) containing nanofibers via electrospinning has been demonstrated. AgNPs were in situ synthesized in poly (vinyl alcohol) (PVA)/carboxymethyl-chitosan (CM-chitosan) blend aqueous solution before electrospinning. UV-vis spectra, viscosity and conductivity of the electrospinning solution were measured to investigate their effects on the electrospinning procedure. The morphology of AgNPs/PVA/CM-chitosan nanofibers was observed by Field Emission Scanning Electron Microscopy. The formation and morphology of AgNPs were investigated by Transmission Electron Microscopy and X-ray Photoelectron Spectroscopy. The resulted nanofibers have smooth surface and uniform diameters ranging from 295 to 343 nm. The diameters of AgNPs mainly distributed in the range of 4-14 nm, and the electrostatic interaction between AgNPs and fibers was observed. Finally, in vitro Ag release from the nanofibers was measured and the antibacterial behavior of the nanofibers against Escherichia coli was studied by bacterial growth inhibition halos and bactericidal kinetic testing. The AgNPs/PVA/CM-chitosan nanofibers possessed certain antibacterial ability, which makes them capable for antibacterial biomaterials.

  17. Fault detection and analysis in nuclear research facility using artificial intelligence methods

    Science.gov (United States)

    Ghazali, Abu Bakar; Ibrahim, Maslina Mohd

    2016-01-01

    In this article, an online detection of transducer and actuator condition is discussed. A case study is on the reading of area radiation monitor (ARM) installed at the chimney of PUSPATI TRIGA nuclear reactor building, located at Bangi, Malaysia. There are at least five categories of abnormal ARM reading that could happen during the transducer failure, namely either the reading becomes very high, or very low/ zero, or with high fluctuation and noise. Moreover, the reading may be significantly higher or significantly lower as compared to the normal reading. An artificial neural network (ANN) and adaptive neuro-fuzzy inference system (ANFIS) are good methods for modeling this plant dynamics. The failure of equipment is based on ARM reading so it is then to compare with the estimated ARM data from ANN/ ANFIS function. The failure categories in either `yes' or `no' state are obtained from a comparison between the actual online data and the estimated output from ANN/ ANFIS function. It is found that this system design can correctly report the condition of ARM equipment in a simulated environment and later be implemented for online monitoring. This approach can also be extended to other transducers, such as the temperature profile of reactor core and also to include other critical actuator conditions such as the valves and pumps in the reactor facility provided that the failure symptoms are clearly defined.

  18. Preparing hydrophobic nanocellulose-silica film by a facile one-pot method.

    Science.gov (United States)

    Le, Duy; Kongparakul, Suwadee; Samart, Chanatip; Phanthong, Patchiya; Karnjanakom, Surachai; Abudula, Abuliti; Guan, Guoqing

    2016-11-20

    Hydrophobic nanocellulose-silica film was successfully prepared by a facile one-pot method using tetraethoxysilane (TEOS) and dodecyl triethoxylsilane (DTES). Morphological characterization of the hydrophobic nanocellulose-silica (NC-SiO2-DTES) film showed well self-assembled DTES modified silica spherical nanoparticles with the particle sizes in the range of 88-126nm over the nanocellulose film. The hydrophobicity of the NC-SiO2-DTES film was achieved owing to the improvement of roughness of the nanocellulose film by coating dodecyl- terminated silica nanoparticles. An increase in DTES loading amount and reaction time increased the hydrophobicity of the film, and the optimum condition for NC-SiO2-DTES film preparation was achieved at DTES/TEOS molar ratio of 2.0 for 8h reaction time. Besides, the NC-SiO2-DTES film performed superoleophilic property with octane and hexadecane contact angles of 0°. It also showed an excellent hydrophobic property over all pH values ranged from 1 to 14.

  19. 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 ...

  20. Vapor-phase hydrothermal transformation of HTiOF3 intermediates into {001} faceted anatase single-crystalline nanosheets.

    Science.gov (United States)

    Liu, Porun; Wang, Yun; Zhang, Haimin; An, Taicheng; Yang, Huagui; Tang, Zhiyong; Cai, Weiping; Zhao, Huijun

    2012-12-07

    For the first time, a facile, one-pot hydrofluoric acid vapor-phase hydrothermal (HF-VPH) method is demonstrated to directly grow single-crystalline anatase TiO(2) nanosheets with 98.2% of exposed {001} faceted surfaces on the Ti substrate via a distinctive two-stage formation mechanism. The first stage produces a new intermediate crystal (orthorhombic HTiOF(3) ) that is transformed into anatase TiO(2) nanosheets during the second stage. The findings reveal that the HF-VPH reaction environment is unique and differs remarkably from that of liquid-phase hydrothermal processes. The uniqueness of the HF-VPH conditions can be readily used to effectively control the nanostructure growth.

  1. 230Th/238U dating of hydrothermal sulfides from Duanqiao hydrothermal field, Southwest Indian Ridge

    Science.gov (United States)

    Yang, Weifang; Tao, Chunhui; Li, Huaiming; Liang, Jin; Liao, Shili; Long, Jiangping; Ma, Zhibang; Wang, Lisheng

    2016-11-01

    Duanqiao hydrothermal field is located between the Indomed and Gallieni fracture zones at the central volcano, at 50°28'E in the ultraslow-spreading Southwest Indian Ridge (SWIR). Twenty-eight subsamples from a relict chimney and massive sulfides were dated using the 230Th/238U method. Four main episodes of hydrothermal activity were determined according to the restricted results: 68.9-84.3, 43.9-48.4, 25.3-34.8, and 0.7-17.3 kyrs. Hydrothermal activity of Duanqiao probably started about 84.3 (±0.5) kyrs ago and ceased about 0.737 (±0.023) kyrs ago. The periodic character of hydrothermal activity may be related to the heat source provided by the interaction of local magmatism and tectonism. The estimated mean growth rate of the sulfide chimney is Dragon Flag field is much more recent than that of Duanqiao or Mt. Jourdanne fields. The massive sulfides are younger than the sulfides from other hydrothermal fields such as Rainbow, Sonne and Ashadze-2. The preliminarily estimated reserves of sulfide ores of Duanqiao are approximately 0.5-2.9 million tons.

  2. Short run hydrothermal coordination with network constraints using an interior point method Coordinación hidrotérmica de corto plazo con restricciones de red usando un método de punto interior

    Directory of Open Access Journals (Sweden)

    Jesús María López Lezama

    2008-12-01

    Full Text Available This paper presents a lineal optimization model to solve the hydrothermal coordination problem. The main contribution of this work is the inclusion of the network constraints to the hydrothermal coordination problem and its solution using an interior point method. The proposed model allows working with a system that can be completely hydraulic, thermal or mixed. Results are presented on the IEEE 14 bus test system.En este artículo se presenta un modelo de optimización lineal para resolver el problema de la coordinación hidrotérmica. El principal aporte de este trabajo es la inclusión de las restricciones de red al problema de coordinación hidrotérmica y su solución usando un método de punto interior. El modelo propuesto permite manejar un sistema completamente hídrico, completamente térmico o un sistema mixto. Se presentan resultados para el sistema de prueba IEEE de 14 barras.

  3. Synthesis of BiFeO{sub 3} thin films on single-terminated Nb : SrTiO{sub 3} (111) substrates by intermittent microwave assisted hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Velasco-Davalos, Ivan; Ambriz-Vargas, Fabian; Kolhatkar, Gitanjali; Thomas, Reji, E-mail: ruediger@emt.inrs.ca, E-mail: reji.thomas@emt.inrs.ca; Ruediger, Andreas, E-mail: ruediger@emt.inrs.ca, E-mail: reji.thomas@emt.inrs.ca [Centre Énergie, Matériaux et Télécommunications, INRS, 1650 Lionel-Boulet, Varennes, Québec, J3X1S2 (Canada)

    2016-06-15

    We report on a simple and fast procedure to create arrays of atomically flat terraces on single crystal SrTiO{sub 3} (111) substrates and the deposition of ferroelectric BiFeO{sub 3} thin films on such single-terminated surfaces. A microwave-assisted hydrothermal method in deionized water and ammonia solution selectively removes either (SrO{sub 3}){sup 4−} or Ti{sup 4+} layers to ensure the same chemical termination on all terraces. Measured step heights of 0.225 nm (d{sub 111}) and uniform contrast in the phase image of the terraces confirm the single termination in pure and Nb doped SrTiO{sub 3} single crystal substrates. Multiferroic BiFeO{sub 3} thin films were then deposited by the same microwave assisted hydrothermal process on Nb : SrTiO{sub 3} (111) substrates. Bi(NO{sub 3}){sub 3} and Fe(NO{sub 3}){sub 3} along with KOH served as the precursors solution. Ferroelectric behavior of the BiFeO{sub 3} films on Nb : SrTiO{sub 3} (100) substrates was verified by piezoresponse force microscopy.

  4. Decoration of ZnO Nanorods with Coral Reefs like NiO Nanostructures by the Hydrothermal Growth Method and Their Luminescence Study

    Directory of Open Access Journals (Sweden)

    Mazhar Ali Abbasi

    2014-01-01

    Full Text Available Composite nanostructures of coral reefs like p-type NiO/n-type ZnO were synthesized on fluorine-doped tin oxide glass substrates by hydrothermal growth. Structural characterization was performed by field emission scanning electron microscopy, high-resolution transmission electron microscopy, and X-ray diffraction techniques. This investigation shows that the adopted synthesis leads to high crystalline quality nanostructures. The morphological study shows that the coral reefs like nanostructures are densely packed on the ZnO nanorods. Cathodoluminescence (CL spectra for the synthesized composite nanostructures are dominated mainly by a broad interstitial defect related luminescence centered at ~630 nm. Spatially resolved CL images reveal that the luminescence of the decorated ZnO nanostructures is enhanced by the presence of the NiO.

  5. Synthesis and characterization of high-quality water-soluble CdMnTe quantum dots capped by N-acetyl-L-cysteine through hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Fang; Li, Jiaotian; Wang, Fengxue; Yang, Tanming; Zhao, Dan, E-mail: wqzhdpai@163.com

    2015-03-15

    High-quality water-soluble Mn{sup 2+} doped CdTe quantum dots (QDs) with N-acetyl-L-cysteine (NAC) as capping reagent have been synthesized through hydrothermal route, allowing a rapid preparation time (<1 h), tunable emitting peaks (from 530 to 646 nm) and excellent quantum yields (approximately 50%). The influences of various experimental variables, including Mn-to-Cd ratio, Te-to-Cd ratio, pH value, and reaction time on the growth rate and luminescent properties of the obtained QDs have been systematically investigated. And the optimum reaction conditions (Cd:Mn:NAC:Te=1.0:1.0:2.4:0.2, pH=9.5, 35 min, 200 °C) are found out. The optical features and structure of the obtained CdMnTe QDs have been characterized through fluorescence spectroscopy, UV absorption spectroscopy and TEM. In particular, we realized qualitative, semi-quantitative and quantitative studies on the doping of Mn to CdTe QDs through XPS, EDS, and AAS. The actual molar ratio of Mn to Cd in CdMnTe QDs (551 nm) is 1.166:1.00, very close to the feed ratios (1:1). - Highlights: • Mn doped CdTe QDs have been synthesized through one-pot hydrothermal route. • The prepared QDs possess excellent quantum yields as high as 63.1% and tunable emitting peaks from 530 to 646 nm. • We found out that the enhancement of Mn:Cd will decrease the QY of the prepared QDs and lead to the blueshift of emission peaks. • The QDs have been characterized through TEM, EDS, XPS, and AAS.

  6. Synthesis and characterization of hybrid nanostructures produced in the presence of the titanium dioxide and bioactive organic substances by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Zima, Tatyana, E-mail: Zima@solid.nsc.ru [Institute of Solid State Chemistry and Mechanochemistry SB RAS, 18 Kutateladze, Novosibirsk 630128 (Russian Federation); Baklanova, Natalya [Institute of Solid State Chemistry and Mechanochemistry SB RAS, 18 Kutateladze, Novosibirsk 630128 (Russian Federation); Bataev, Ivan [Novosibirsk State Technical University, 20 K. Marx Prospect, Novosibirsk 630092 (Russian Federation)

    2013-02-15

    Hybrid nanostructures produced by hydrothermal treatment of TiO{sub 2} in the presence of bioactive organic substances such as chitosan, aminoterephthalic acid and their mixture have been investigated. Sodium polytitanates as one-dimensional elongated structures with lengths of several hundred of nanometers were obtained in the presence of chitosan and aminoterephthalic acid. With chitosan the elongated nanostructures are formed by successive superposition of structural fragments-nanostrips with well-ordered multilayered morphology and increased distance between successive layers to 1.2 nm. Quite different amorphous products as agglomerates with roundest and rhomboid morphology are formed when the mixture of chitosan and aminoterephthalic acid is added to the reaction system. One can propose that main reason of such behavior is a low rate of diffusion of dissolved Ti(IV) ions in the high viscous mixed chitosan-aminoterephthalic system. An effect of organic substances on the formation, morphology and transformation of various titanates is discussed. - Graphical abstract: The typical images of hybrid nanostructures produced by hydrothermal treatment of TiO{sub 2} in the presence chitosan and mixed chitosan with aminoterephthalic acid. Highlights: Black-Right-Pointing-Pointer Various shapes of TiO{sub 2} based structures can be produced in the presence of organic. Black-Right-Pointing-Pointer An addition of chitosan results in the formation of the elongated nanostructures. Black-Right-Pointing-Pointer These structures have multilayered morphology and increased distance between layers. Black-Right-Pointing-Pointer Different agglomerates are formed when chitosan and aminoterephthalic acid are mixed.

  7. A facile method to prepare a high performance solid-state flexible paper-based supercapacitor

    Energy Technology Data Exchange (ETDEWEB)

    Shieh, Jen-Yu; Zhang, Sheng-Hui; Wu, Cheng-Hung [Institute of Electro-Optical and Materials Science, National Formosa University, 64 Wenhua Road, Huwei, Yunlin 63208, Taiwan (China); Yu, Hsin Her, E-mail: hhyu@nfu.edu.tw [Department of Biotechnology, National Formosa University, 64 Wenhua Road, Huwei, Yunlin 63208, Taiwan (China)

    2014-09-15

    Graphical abstract: A flexible paper-based supercapacitor was assembled into a sandwich structure, which exhibits well-retained triangular-shaped curves. The cycle life stability of this device still retains about 96% of the initial capacitance after 2000 cycles at a scan rate of 400 mV/s. An as-fabricated paper-based supercapacitor could light a red LED well after charging at constant potential of 3 V. - Highlights: • A facile approach is proposed to fabricate paper-based supercapacitors. • Apple pectin is an excellent dispersant for MWCNTs. • Paper provides a strong binding and flexible characteristic for electrode. • A paper-based supercapacitor could light a red LED after charging. • This device shows excellent electrochemical performance and cycling stability. - Abstract: We propose a low cost and simple method to prepare a paper-based supercapacitor in this study. Multi-walled carbon nanotubes (MWCNTs) were dispersed with a pectin solution under an ultrasonic homogenizer. Carbon nanotube suspension was prepared using a centrifuge to eliminate impurities. The dispersed MWCNTs suspension was dropped and dried onto the shallow surface of commercial copy paper. A paper-based conductive paper was formed as the electrodes. The electrical conductivity and dispersed morphology of the paper-based conductive paper were examined by four probes, atomic force microscope (AFM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The solid-state electrolyte was prepared by casting a solution of phosphoric acid and polyvinyl alcohol onto a glass plate. The paper-based supercapacitor was constructed with one solid-state electrolyte inserted between two electrodes, which were assembled into a sandwich structure by hot press. The specific capacitance and cycle-life stability of the paper-based supercapacitor was investigated by cyclic voltammetry analysis.

  8. Analysis Methods for Extracting Knowledge from Large-Scale WiFi Monitoring to Inform Building Facility Planning

    DEFF Research Database (Denmark)

    Ruiz-Ruiz, Antonio; Blunck, Henrik; Prentow, Thor Siiger

    2014-01-01

    realistic data to inform facility planning. In this paper, we propose analysis methods to extract knowledge from large sets of network collected WiFi traces to better inform facility management and planning in large building complexes. The analysis methods, which build on a rich set of temporal and spatial...... features, include methods for noise removal, e.g., labeling of beyond building-perimeter devices, and methods for quantification of area densities and flows, e.g., building enter and exit events, and for classifying the behavior of people, e.g., into user roles such as visitor, hospitalized or employee...... noise removal of beyond building perimeter devices. We furthermore present detailed statistics from our analysis regarding people’s presence, movement and roles, and example types of visualizations that both highlight their potential as inspection tools for planners and provide interesting insights...

  9. Tuning photoluminescence of organic rubrene nanoparticles through a hydrothermal process

    Directory of Open Access Journals (Sweden)

    Jung Hyunjung

    2011-01-01

    Full Text Available Abstract Light-emitting 5,6,11,12-tetraphenylnaphthacene (rubrene nanoparticles (NPs prepared by a reprecipitation method were treated hydrothermally. The diameters of hydrothermally treated rubrene NPs were changed from 100 nm to 2 μm, depending on hydrothermal temperature. Photoluminescence (PL characteristics of rubrene NPs varied with hydrothermal temperatures. Luminescence of pristine rubrene NPs was yellow-orange, and it changed to blue as the hydrothermal temperature increased to 180°C. The light-emitting color distribution of the NPs was confirmed using confocal laser spectrum microscope. As the hydrothermal temperature increased from 110°C to 160°C, the blue light emission at 464 to approximately 516 nm from filtered-down NPs was enhanced by H-type aggregation. Filtered-up rubrene NPs treated at 170°C and 180°C exhibited blue luminescence due to the decrease of intermolecular excimer densities with the rapid increase in size. Variations in PL of hydrothermally treated rubrene NPs resulted from different size distributions of the NPs.

  10. 基于生物质甘蔗渣的荧光碳量子点制备%Facile synthesis of fluorescent carbon nanodots derived from biomass bagasse by hydrothermal treatment

    Institute of Scientific and Technical Information of China (English)

    陈文新; 阳运华; 刘应亮; 曹喜民

    2015-01-01

    本实验以富含纤维素的废弃生物质甘蔗渣为原料,采用水热法合成了具有荧光性能的碳量子点。对碳量子点进行了表征,其粒径大小约为5~10 nm;在紫外灯照射下发蓝色荧光,对其荧光性能进行了研究,发现其具有多元激发、多元发射的性质。对其细胞毒性进行了研究,结果表明是一种生物相容性良好的标记材料。%We developed a hydrothermal carbonization route to prepare carbon quantum dots (CQDs) by using sugarcane bagasse-an agricultural waste as carbon precursor.The obtained CQDs had a size dis-tribution of 5 ~10 nm.The fluorescence property of the CQDs was the same as the other carbon dots, having multiple excitation and multiple emission.

  11. Methods of Dust Air Flows Reduction at Ore Transfer Facilities of Mining and Processing Plants

    Directory of Open Access Journals (Sweden)

    Gulmira K. Saparova

    2013-01-01

    Full Text Available The article describes the most typical schemes of ore stationary transfers. Aspirate units, depending on dust intensity are divided into three groups. Typical schemes of stationary transfers were presented. On the ground of the research, the classification of ore transfer facilities types at mining and processing plants was offered

  12. Methods for using computer training facilities in studies of special disciplines

    Directory of Open Access Journals (Sweden)

    O.L. Tashlykov

    2016-12-01

    The use of the analytical simulator is illustrated by a laboratory research project entitled “BN-800 Reactor Power Maneuvering”, which investigates the reactor facility power control modes in a power range of 100–80–100% of the rated power.

  13. 42 CFR 412.632 - Method of payment under the inpatient rehabilitation facility prospective payment system.

    Science.gov (United States)

    2010-10-01

    ... rehabilitation facility's preparation and submittal of bills to the intermediary beyond its normal billing cycle... costs for each discharge only following submission of a discharge bill. (b) Periodic interim payments—(1... outlier payments are made based on the submission of a discharge bill and represent final payment....

  14. A method for targeting air samplers for facility monitoring in an urban environment

    Science.gov (United States)

    Bieringer, Paul E.; Longmore, Scott; Bieberbach, George; Rodriguez, Luna M.; Copeland, Jeff; Hannan, John

    2013-12-01

    /Exceedence spatial maps for prescribed concentration thresholds or standards. The method is flexible and can be tuned to allow the detailed characterization of Probability of Detection (POD) for a given sampler detection threshold and sampling period (e.g. sampling duration, season, time of day). An example of this methodology is illustrated for a single facility in an urban location surrounded by numerous multi-story buildings.

  15. A novel and facile synthesis of carbon quantum dots via salep hydrothermal treatment as the silver nanoparticles support: Application to electroanalytical determination of H2O2 in fetal bovine serum.

    Science.gov (United States)

    Jahanbakhshi, Mojtaba; Habibi, Biuck

    2016-07-15

    A simple, low-cost, and green process was used for the synthesis of carbon quantum dots (CQDs) through the hydrothermal treatment of salep as a novel bio-polymeric carbon source in presence of only pure water. The silver nanoparticles (AgNPs) were embedded on the surface of CQDs by ultra-violate (UV) irradiation to the CQDs and silver nitrate mixture solution. The as-synthesized CQDs and AgNPs decorated CQDs nanohybrid (AgNPs/CQDs) were characterized by UV-vis and photoluminescence spectroscopy, Fourier transform-infrared spectroscopy, transmission electron microscopy, atomic force microcopy, X-ray diffraction, and field emission scanning electron microscopy. Then, the AgNPs/CQDs nanohybrid was casted on the glassy carbon electrode in order to prepare an amperometric hydrogen peroxide (H2O2) sensor. The electrochemical investigations show that the AgNPs/CQDs nanohybrid possesses an excellent performance toward the H2O2 reduction. In the optimum condition, the linear range of H2O2 determination was achieved from 0.2 to 27.0μM with high sensitivity (1.5μA/µM) and the limit of detection was obtained about 80nM (S/N=3). Finally, the prepared nanohybrid modified electrode was effectively applied to the H2O2 detection in the disinfected fetal bovine serum samples, and the recovery was obtained about 98%. The achieved results indicate that the AgNPs/CQDs nanohybrid with high reproducibility, repeatability, and stability has a favorable capability in electrochemical sensors improvement.

  16. One-Step Synthesis of High-Quality Water-Soluble CdSe Quantum Dots Capped by N-Acetyl-L-cysteine via Hydrothermal Method and Their Characterization

    Directory of Open Access Journals (Sweden)

    Chunjin Wei

    2015-01-01

    Full Text Available Novel water-soluble CdSe quantum dots (QDs have been prepared with N-acetyl-L-cysteine as new stabilizer through a one-step hydrothermal route. The influence of experimental conditions, including reaction time, molar ratio of reactants, and pH value, on the luminescent properties of the obtained CdSe QDs has been systematically investigated. The characterization of as-prepared QDs was carried out through different methods. In particular, we realized qualitative and semiquantitative studies on CdSe QDs through X-ray photoelectron spectroscopy and electron diffraction spectroscopy. The results show that the as-prepared CdSe QDs exhibit a high quantum yield (up to 26.7%, high stability, and monodispersity and might be widely used in biochemical detection and biochemical research.

  17. Synthesis and luminescence properties of red long-lasting phosphor Y{sub 2}O{sub 2}S:Eu{sup 3+}, Zn{sup 2+}, Ti{sup 4+} nanotubes via hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Ping; Liu, Dan; Jiang, Guowei [Taiyuan University of Technology, College of Physics and Optoelectronics, Taiyuan (China); Cui, Cai E.; Wang, Lei [Taiyuan University of Technology, College of Physics and Optoelectronics, Taiyuan (China); Taiyuan University of Technology, Observation and Control Technology Research Institute, Taiyuan (China)

    2014-08-15

    Red long-lasting phosphor Y{sub 2}O{sub 2}S:Eu{sup 3+}, Zn{sup 2+}, Ti{sup 4+} nanotubes were prepared by hydrothermal method. Powder X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence and thermoluminescence spectra (TL) were used to characterize the long-lasting phosphor. XRD investigation revealed that the product synthesised under 750 C for 6 h was a pure phase of Y{sub 2}O{sub 2}S. SEM observation showed that the sulfuretted phosphor inherited the tube-like shape from the precursor. Under 325 nm UV excitation, the result indicated the strongest red-emission lines at 627 nm, corresponded to the transition from {sup 5}D{sub 0} to {sup 7}F{sub 2} level of Eu{sup 3+} ion. Both the afterglow decay curves and TL curves revealed that the phosphor had efficient luminescent and excellent long-lasting properties. (orig.)

  18. Fabrication of TiO2 nanorods/nanosheets photoelectrode on Ti mesh by hydrothermal method for degradation of methylene blue:influence of calcination temperature

    Science.gov (United States)

    Deng, Xiaoyong; Ma, Qiuling; Cui, Yuqi; Cheng, Xiuwen; Cheng, Qingfeng

    2017-10-01

    In the study, Using the strategy of hydrothermal reaction followed by annealing at different temperatures, TiO2 nanorods/nanosheets (NRs/NSs) photoelectrodes with diverse microcosmic morphologies and crystal structures were successfully fabricated. Moreover, all samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and Ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS). Meanwhile the photoelectrochemical (PECH) properties were recorded through open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) curves. The photocatalytic (PC) activity of TiO2 NRs/NSs photoelectrodes were further measured by methylene blue (MB) degradation. Results suggest that the nanosheets possessed the width and thickness in the range of 100-400 and 10-20 nm, and the nanorods possessed the diameter in the range of around 10-20 nm, respectively. Also, the TiO2 NRs/NSs photoelectrode calcined at 500 °C exhibited the best proportion of both nanosheets and nanorods and higher photocatalytic activity (73.56%) than those of other TiO2 NRs/NSs photoelectrodes within 150 min under visible light illumination, which was ascribed to higher photoproduction electrons-holes (e/h+) pairs separation and visible light absorption. Therefore, the calcination temperature plays a significant role in altering the morphology and crystal structure of TiO2 NRs/NSs photoelectrode, and then enhanced PC performance.

  19. Growth behavior and electrical performance of Ga-doped ZnO nanorod/p-Si heterojunction diodes prepared using a hydrothermal method.

    Science.gov (United States)

    Park, Geun Chul; Hwang, Soo Min; Lim, Jun Hyung; Joo, Jinho

    2014-01-01

    The incorporation of foreign elements into ZnO nanostructures is of significant interest for tuning the structure and optical and electrical properties in nanoscale optoelectronic devices. In this study, Ga-doped 1-D ZnO nanorods were synthesized using a hydrothermal route, in which the doping content of Ga was varied from 0% to 10%. The pn heterojunction diodes based on the n-type Ga-doped ZnO nanorod/p-type Si substrates were constructed, and the effect of the Ga doping on the morphology, chemical bonding structure, and optical properties of the ZnO nanorods was systematically investigated as well as the diode performance. With increasing Ga content, the average diameter of the ZnO nanorods was increased, whereas the amount of oxygen vacancies was reduced. In addition, the Ga-doped ZnO nanorod/p-Si diodes showed a well-defined rectifying behavior in the I-V characteristics and an improvement in the electrical conductivity (diode performance) by the Ga doping, which was attributed to the increased charge carrier (electron) concentration and the reduced defect states in the nanorods by incorporating Ga. The results suggest that Ga doping is an effective way to tailor the morphology, optical, electronic, and electrical properties of ZnO nanorods for various applications such as field-effect transistors (FETs), light-emitting diodes (LEDs), and laser diodes (LDs).

  20. Synthesis of monodisperse spherical core-shell SiO2-SrAl2Si2 O8:Eu2+ phosphors by hydrothermal homogeneous precipitation method

    Directory of Open Access Journals (Sweden)

    Yidong Li, Liyuan Xiao, Yingliang Liu, Pengfei Ai and Xiaobo Chen

    2010-01-01

    Full Text Available Nanocrystalline SrAl2Si2 O8 :Eu2+ phosphor layers were coated on nonaggregated, monodisperse and spherical SiO2 particles using a hydrothermal homogeneous precipitation. After annealing at 1100 °C, core-shell SiO2@SrAl2 Si2 O8 :Eu2+ particles were obtained. They were characterized with x-ray diffraction (XRD, scanning electron microscopy, transmission electron microscopy and photoluminescence techniques. XRD analysis confirmed the formation of SiO2 @SrAl2 Si2 O8 :Eu2+ particles; it indicated that the SrAl2 Si2 O8 :Eu2+ shells on SiO2 particles consisted of hexagonal crystallites. The core-shell phosphors obtained are well-dispersed submicron spherical particles with a narrow size distribution. The thickness of the coated layer is approximately 20–40 nm. Under ultraviolet excitation (361 nm, the particles emit blue light at about 440 nm due to the Eu2+ ions in their shells.