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Sample records for intercalated ironii ironiii

  1. Oxidation of Dodecanoate Intercalated Iron(II)–Iron(III) Layered Double Hydroxide to Form 2D Iron(III) (Hydr)oxide Layers

    DEFF Research Database (Denmark)

    Huang, Li‐Zhi; Ayala‐Luis, Karina B.; Fang, Liping

    2013-01-01

    hydroxide planar layer were preserved during the oxidation, as shown by FTIR spectroscopy. The high positive charge in the hydroxide layer produced by the oxidation of iron(II) to iron(III) is partially compensated by the deprotonation of hydroxy groups, as shown by X‐ray photoelectron spectroscopy...... between the alkyl chains of the intercalated dodecanoate anions play a crucial role in stabilizing the structure and hindering the collapse of the iron(II)–iron(III) (hydr)oxide structure during oxidation. This is the first report describing the formation of a stable planar layered octahedral iron......(III) (hydr)oxide. oxGRC12 shows promise as a sorbent and host for hydrophobic reagents, and as a possible source of single planar layers of iron(III) (hydr)oxide....

  2. The preparation of magnetite from iron(III) and iron(II) salt solutions

    International Nuclear Information System (INIS)

    Segal, D.L.

    1980-10-01

    Methods are described for the preparation of magnetite from iron(III) and iron(II) salt solutions at temperatures between 295 to 373 K. The effect of the reagent concentration, a chelating agent and different alkali-metal cations on the formation of magnetite has been investigated. The magnetite samples have been examined by X-ray diffraction, transmission electron microscopy, adsorption of nitrogen, emission spectroscopy, X-ray photoelectron spectroscopy and by determination of the point of zero charge. A review of previous work on the preparation of magnetite in an aqueous environment is also included. This work is relevant to the corrosion processes which can occur in the water coolant circuits of nuclear reactors. (author)

  3. Multisensor system for determination of iron(II), iron(III) and uranium(VI) in complex solutions

    International Nuclear Information System (INIS)

    Legin, A.V.; Seleznev, B.L.; Rudnitskaya, A.M.; Vlasov, Yu.G.

    1998-01-01

    The aim of the present paper is the development and analytical evaluation of a multisensor system for determination of low content of iron(II), iron(III) and uranium(VI) in complex aqueous media. Sensor array included sensors on the basis of chalcogenide vitreous materials with redox and ionic cross-sensitivities, crystalline silver sulphide electrode, noble metal electrodes Pt, Au, Ag and redox sensor on the basis of oxide glass. Potentiometric measurements have been taken in a conventional electrochemical cell vs. a standard Ag/AgCl reference electrode. All measurements have been taken at room temperature. Calibration solutions contained UO 2 (NO 3 ) 2 in concentration range 10 -6 -1,610 -5 mol/L, K 3 Fe(CN) 6 and K 4 Fe(CN) 6 or FeSO 4 (NH 4 ) 2 SO 4 and FeCl 3 , with the ratio of Fe(II)/Fe(III) concentration from 100:1 to 1:100, the total concentration of Fe was 10 -4 and 10 -5 mol/L. All solutions have been made on the background electrolyte of calcium and magnesium chlorides and sulphates with the fixed content of 5-27 mmol/L of each component which is a typical one for groundwater or mining water. Sensor potentials have been processed by a back-propagation artificial neural net. Average error of determination of Fe(II) and Fe(III) is about 20 %, of uranium(VI) - 40 %. It was found that sensitivity of the sensor array to iron and uranium is irrespective of the chemical form of these species

  4. Multisensor system for determination of iron(II), iron(III), uranium(VI) and uranium(IV) in complex solutions

    International Nuclear Information System (INIS)

    Legin, A.V.; Seleznev, B.L.; Rudnitskaya, A.M.; Vlasov, Yu.G.; Tverdokhlebov, S.V.; Mack, B.; Abraham, A.; Arnold, T.; Baraniak, L.; Nitsche, H.

    1999-01-01

    Development and analytical evaluation of a multisensor system based on the principles of 'electronic tongue' for the determination of low contents of uranium(VI), uranium(IV), iron(II) and iron(III) in complex aqueous media have been carried out. A set of 29 different chemical sensors on the basis of all- solid-state crystalline and vitreous materials with enhanced electronic conductivity and redox and ionic cross-sensitivity have been incorporated into the sensor array. Multidimensional data have been processed by pattern recognition methods such as artificial neural networks and partial least squares. It has been demonstrated that Fe(II) and Fe(III) contents in the range from 10 -7 to 10 -4 mol L -1 of total iron concentration can be determined with the average precision of about 25 %. U(VI) and U(IV) contents can been determined with the average precision of 10-40% depending on the concentration. The developed multisensor system can be applied in future for the analysis of mining and borehole waters as well other contaminated natural media, including on-site measurements. (author)

  5. A highly sensitive amperometric sensor for oxygen based on iron(II) tetrasulfonated phthalocyanine and iron(III) tetra-(N-methyl-pyridyl)-porphyrin multilayers

    International Nuclear Information System (INIS)

    Duarte, Juliana C.; Luz, Rita C.S.; Damos, Flavio S.; Tanaka, Auro A.; Kubota, Lauro T.

    2008-01-01

    The development of a highly sensitive sensor for oxygen is proposed using a glassy carbon (GC) electrode modified with alternated layers of iron(II) tetrasulfonated phthalocyanine (FeTsPc) and iron(III) tetra-(N-methyl-pyridyl)-porphyrin (FeT4MPyP). The modified electrode showed excellent catalytic activity for the oxygen reduction. The reduction potential of the oxygen was shifted about 330 mV toward less negative values with this modified electrode, presenting a peak current much higher than those observed on a bare GC electrode. Cyclic voltammetry and rotating disk electrode (RDE) experiments indicated that the oxygen reduction reaction involves 4 electrons with a heterogenous rate constant (k obs ) of 3 x 10 5 mol -1 L s -1 . A linear response range from 0.2 up to 6.4 mg L -1 , with a sensitivity of 4.12 μA L mg -1 (or 20.65 μA cm -2 L mg -1 ) and a detection limit of 0.06 mg L -1 were obtained with this sensor. The repeatability of the proposed sensor, evaluated in terms of relative standard deviation (R.S.D.) was 2.0% for 10 measurements of a solution of 6.4 mg L -1 oxygen. The sensor was applied to determine oxygen in pond and tap water samples showing to be a promising tool for this purpose

  6. Arsenic removal with iron(II) and iron(III) in waters with high silicate and phosphate concentrations.

    Science.gov (United States)

    Roberts, Linda C; Hug, Stephan J; Ruettimann, Thomas; Billah, Morsaline; Khan, Abdul Wahab; Rahman, Mohammad Tariqur

    2004-01-01

    Arsenic removal by passive treatment, in which naturally present Fe(II) is oxidized by aeration and the forming iron(III) (hydr)oxides precipitate with adsorbed arsenic, is the simplest conceivable water treatment option. However, competing anions and low iron concentrations often require additional iron. Application of Fe(II) instead of the usually applied Fe(III) is shown to be advantageous, as oxidation of Fe(II) by dissolved oxygen causes partial oxidation of As(III) and iron(III) (hydr)oxides formed from Fe(II) have higher sorption capacities. In simulated groundwater (8.2 mM HCO3(-), 2.5 mM Ca2+, 1.6 mM Mg2+, 30 mg/L Si, 3 mg/L P, 500 ppb As(III), or As(V), pH 7.0 +/- 0.1), addition of Fe(II) clearly leads to better As removal than Fe(III). Multiple additions of Fe(II) further improved the removal of As(II). A competitive coprecipitation model that considers As(III) oxidation explains the observed results and allows the estimation of arsenic removal under different conditions. Lowering 500 microg/L As(III) to below 50 microg/L As(tot) in filtered water required > 80 mg/L Fe(III), 50-55 mg/L Fe(II) in one single addition, and 20-25 mg/L in multiple additions. With As(V), 10-12 mg/L Fe(II) and 15-18 mg/L Fe(III) was required. In the absence of Si and P, removal efficiencies for Fe(II) and Fe(III) were similar: 30-40 mg/L was required for As(II), and 2.0-2.5 mg/L was required for As(V). In a field study with 22 tubewells in Bangladesh, passive treatment efficiently removed phosphate, but iron contents were generally too low for efficient arsenic removal.

  7. Characterization of a tricationic trigonal bipyramidal iron(IV) cyanide complex, with a very high reduction potential, and its iron(II) and iron(III) congeners.

    Science.gov (United States)

    England, Jason; Farquhar, Erik R; Guo, Yisong; Cranswick, Matthew A; Ray, Kallol; Münck, Eckard; Que, Lawrence

    2011-04-04

    Currently, there are only a handful of synthetic S = 2 oxoiron(IV) complexes. These serve as models for the high-spin (S = 2) oxoiron(IV) species that have been postulated, and confirmed in several cases, as key intermediates in the catalytic cycles of a variety of nonheme oxygen activating enzymes. The trigonal bipyramidal complex [Fe(IV)(O)(TMG(3)tren)](2+) (1) was both the first S = 2 oxoiron(IV) model complex to be generated in high yield and the first to be crystallographically characterized. In this study, we demonstrate that the TMG(3)tren ligand is also capable of supporting a tricationic cyanoiron(IV) unit, [Fe(IV)(CN)(TMG(3)tren)](3+) (4). This complex was generated by electrolytic oxidation of the high-spin (S = 2) iron(II) complex [Fe(II)(CN)(TMG(3)tren)](+) (2), via the S = 5/2 complex [Fe(III)(CN)(TMG(3)tren)](2+) (3), the progress of which was conveniently monitored by using UV-vis spectroscopy to follow the growth of bathochromically shifting ligand-to-metal charge transfer (LMCT) bands. A combination of X-ray absorption spectroscopy (XAS), Mössbauer and NMR spectroscopies was used to establish that 4 has a S = 0 iron(IV) center. Consistent with its diamagnetic iron(IV) ground state, extended X-ray absorption fine structure (EXAFS) analysis of 4 indicated a significant contraction of the iron-donor atom bond lengths, relative to those of the crystallographically characterized complexes 2 and 3. Notably, 4 has an Fe(IV/III) reduction potential of ∼1.4 V vs Fc(+/o), the highest value yet observed for a monoiron complex. The relatively high stability of 4 (t(1/2) in CD(3)CN solution containing 0.1 M KPF(6) at 25 °C ≈ 15 min), as reflected by its high-yield accumulation via slow bulk electrolysis and amenability to (13)C NMR at -40 °C, highlights the ability of the sterically protecting, highly basic peralkylguanidyl donors of the TMG(3)tren ligand to support highly charged high-valent complexes.

  8. Synthesis of linear alkylbenzene sulphonate intercalated iron(II) iron(III) hydroxide sulphate (green rust) and adsorption of carbon tetrachloride

    DEFF Research Database (Denmark)

    Ayala Luis, Karina Barbara; Kaldor, D.K.; Bender Koch, Christian

    2007-01-01

    ) into the interlayer space of synthetic sulphate green rust, GR . Mössbauer analysis of GRLAS indicates that the structure of the organo-GR is very similar to SO4 that of the initial GR with regard to the FeII/FeIII ratio and local coordination of Fe atoms. X-ray SO4 diffraction demonstrates that the GRLAS formed...

  9. Polypyridyl iron(II) complexes showing remarkable photocytotoxicity ...

    Indian Academy of Sciences (India)

    reported a high spin (S=5/2) ternary iron(III) complex. [Fe(BHA)(L)Cl] of a ... designed low-spin iron(II) complexes as a new class of ..... They were moderately soluble in methanol, ethanol and .... Cell permeable DCFDA on oxidation by cel-.

  10. Nonanuclear Spin-Crossover Complex Containing Iron(II) and Iron(III) Based on a 2,6-Bis(pyrazol-1-yl)pyridine Ligand Functionalized with a Carboxylate Group.

    Science.gov (United States)

    Abhervé, Alexandre; Recio-Carretero, María José; López-Jordà, Maurici; Clemente-Juan, Juan Modesto; Canet-Ferrer, Josep; Cantarero, Andrés; Clemente-León, Miguel; Coronado, Eugenio

    2016-09-19

    The synthesis and magnetostructural characterization of [Fe(III)3(μ3-O)(H2O)3[Fe(II)(bppCOOH)(bppCOO)]6](ClO4)13·(CH3)2CO)6·(solvate) (2) are reported. This compound is obtained as a secondary product during synthesis of the mononuclear complex [Fe(II)(bppCOOH)2](ClO4)2 (1). The single-crystal X-ray diffraction structure of 2 shows that it contains the nonanuclear cluster of the formula [Fe(III)3(μ3-O)(H2O)3[Fe(II)(bppCOOH)(bppCOO)]6](13+), which is formed by a central Fe(III)3O core coordinated to six partially deprotonated [Fe(II)(bppCOOH)(bppCOO)](+) complexes. Raman spectroscopy studies on single crystals of 1 and 2 have been performed to elucidate the spin and oxidation states of iron in 2. These studies and magnetic characterization indicate that most of the iron(II) complexes of 2 remain in the low-spin (LS) state and present a gradual and incomplete spin crossover above 300 K. On the other hand, the Fe(III) trimer shows the expected antiferromagnetic behavior. From the structural point of view, 2 represents the first example in which bppCOO(-) acts as a bridging ligand, thus forming a polynuclear magnetic complex.

  11. Iron(II) and Iron(III) Spin Crossover: Toward an Optimal Density Functional

    DEFF Research Database (Denmark)

    Siig, Oliver S; Kepp, Kasper P.

    2018-01-01

    Spin crossover (SCO) plays a major role in biochemistry, catalysis, materials, and emerging technologies such as molecular electronics and sensors, and thus accurate prediction and design of SCO systems is of high priority. However, the main tool for this purpose, density functional theory (DFT......), is very sensitive to applied methodology. The most abundant SCO systems are Fe(II) and Fe(III) systems. Even with average good agreement, a functional may be significantly more accurate for Fe(II) or Fe(III) systems, preventing balanced study of SCO candidates of both types. The present work investigates....../precise, inaccurate/imprecise) are observed. More generally, our work illustrates the importance not only of overall accuracy but also of balanced accuracy for systems likely to occur in context....

  12. Redox process catalysed by growing crystal-strengite, FePO4,2H2O, crystallizing from solution with iron(II) and hydroxylamine

    Science.gov (United States)

    Lundager Madsen, Hans Erik

    2014-09-01

    In an attempt to grow pure crystals of the iron(II) phosphate vivianite, Fe3(PO4)2,8H2O, from a solution of Mohr's salt, Fe(NH4)2(SO4)2,6H2O, added to a solution of ammonium phosphate, hydroxylammonium chloride, NH3OHCl, was added to the iron(II) stock solution to eliminate oxidation of iron(II) by oxygen from the air. However, the effect turned out to be the opposite of the expected: whereas hydroxylamine reduces iron(III) in bulk solution, it acted as a strong oxidant in the presence of growing iron phosphate crystals, causing the crystallization of the iron(III) phosphate strengite, FePO4,2H2O, as the only solid phase. Evidently the crystal surface catalyses oxidation of iron(II) by hydroxylamine. The usual composite kinetics of spiral growth and surface nucleation was found. The surface-nucleation part yielded edge free energy λ in the range 12-45 pJ/m, virtually independent of temperature and in the range typical for phosphates of divalent metals. The scatter of values for λ presumably arises from contributions from different crystal forms to the overall growth rate. The low mean value points to strong adsorption of iron(II), which is subsequently oxidized at the crystal surface, forming strengite. The state of the system did not tend to thermodynamic equilibrium, but to a metastable state, presumably controlled by the iron(II) rich surface layer of the crystal. In addition to crystal growth, it was possible to measure nucleation kinetics by light scattering (turbidimetry). A point of transition from heterogeneous to homogeneous nucleation was found, and from the results for the homogeneous domain a rather precise value of crystal surface free energy γ=55 mJ/m2 was found. This is a relatively low value as well, indicating that the redox process plays a role already at the nucleation stage.

  13. Mononuclear non-heme iron(III)

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 123; Issue 2. Mononuclear non-heme iron(III) complexes of linear and tripodal tridentate ligands as functional models for catechol dioxygenases: Effect of -alkyl substitution on regioselectivity and reaction rate. Mallayan Palaniandavar Kusalendiran Visvaganesan.

  14. Moessbauer spectroscopic evidence for iron(III) complexation and reduction in acidic aqueous solutions of indole-3-butyric acid

    International Nuclear Information System (INIS)

    Kovacs, K.; Kuzmann, E.; Vertes, A.; Kamnev, A.A.; Shchelochkov, A.G.; Medzihradszky-Schweiger, H.; Mink, J.; Hungarian Academy of Sciences, Budapest

    2004-01-01

    Moessbauer spectroscopic studies were carried out in acidic (pH 2.3) 57 Fe III nitrate containing aqueous solutions of indole-3-butyric acid (IBA), rapidly frozen in liquid nitrogen at various periods of time after mixing the reagents. The data obtained show that in solution in the presence of IBA, iron(III) forms a complex with a dimeric structure characterised by a quadrupole doublet, whereas without IBA under similar conditions iron(III) exhibits a broad spectral feature due to a slow paramagnetic spin relaxation which, at liquid nitrogen temperature, results in a large anomalous line broadening (or, at T = 4.2 K, in a hyperfine magnetic splitting). The spectra of 57 Fe III +IBA solutions, kept at ambient temperature under aerobic conditions for increasing periods of time before freezing, contained a gradually increasing contribution of a component with a higher quadrupole splitting. The Moessbauer parameters for that component are typical for iron(II) aquo complexes, thus showing that under these conditions gradual reduction of iron(III) occurs, so that the majority (85%) of dissolved iron(III) is reduced within 2 days. The Moessbauer parameters for the iron(III)-IBA complex in aqueous solution and in the solid state (separated from the solution by filtration) were found to be similar, which may indicate that the dissolved and solid complexes have the same composition and/or iron(III) coordination environment. For the solid complex, the data of elemental analysis suggest the following composition of the dimer: [L 2 Fe-(OH) 2 -FeL 2 ] (where L is indole-3-butyrate). This structure is also in agreement with the data of infrared spectroscopic study of the complex reported earlier, with the side-chain carboxylic group in indole-3-butyrate as a bidentate ligand. The Moessbauer parameters for the solid 57 Fe III -IBA complex at T = 80 K and its acetone solution rapidly frozen in liquid nitrogen were virtually identical, which indicates that the complex retains its

  15. Determination of plutonium in nitric acid solutions - Method by oxidation by cerium(IV), reduction by iron(II) ammonium sulfate and amperometric back-titration with potassium dichromate

    International Nuclear Information System (INIS)

    1987-01-01

    This International Standard specifies a precise and accurate analytical method for determining plutonium in nitric acid solutions. Plutonium is oxidized to plutonium(VI) in a 1 mol/l nitric acid solution with cerium(IV). Addition of sulfamic acid prevents nitrite-induced side reactions. The excess of cerium(IV) is reduced by adding a sodium arsenite solution, catalysed by osmium tetroxide. A slight excess of arsenite is oxidized by adding a 0.2 mol/l potassium permanganate solution. The excess of permanganate is reduced by adding a 0.1 mol/l oxalic acid solution. Iron(III) is used to catalyse the reduction. A small excess of oxalic acid does not interfere in the subsequent plutonium determination. These reduction and oxidation stages can be followed amperometrically and the plutonium is left in the hexavalent state. The sulfuric acid followed by a measured amount of standardized iron(II) ammonium sulfate solution in excess of that required to reduce the plutonium(VI) to plutonium(IV) is added. The excess iron(II) and any plutonium(III) formed to produce iron(III) and plutonium(IV) is amperometrically back-titrated using a standard potassium dichromate solution. The method is almost specifically for plutonium. It is suitable for the direct determination of plutonium in materials ranging from pure product solutions, to fast reactor fuel solutions with a uranium/plutonium ratio of up to 10:1, either before or after irradiation

  16. Toxicological studies and antimicrobial properties of some Iron(III ...

    African Journals Online (AJOL)

    Two iron(III) complexes of Ciprofloxacin were synthesized by reaction of the ligand with iron(III) chloride hexahydrate in different solutions. The nature of bonding of the ligands and the structure of the isolated metal complexes were elucidated on the basis of their physical and spectroscopic studies. The infrared spectra ...

  17. Moessbauer study of iron(III) salicylates

    Energy Technology Data Exchange (ETDEWEB)

    Mahesh, K; Sharma, N D; Gupta, D C [Kurukshetra Univ. (India). Dept. of Physics; Puri, D M [Kurukshetra Univ. (India). Dept. of Chemistry

    1979-07-01

    Moessbauer infrared and magnetic studies of different basic salicylates of iron(III) are reported. Comparison of observed isomer shift and quadrupole splitting with the earlier work allows to assign the trinuclear chain structure to the complexes wherein the central iron atom in the chain is considered to be octahedrally coordinated in case of salicylate and 4-aminosalicylate derivatives, and pentacoordinated for the thiosalicylate with the terminal iron atom in tetrahedral symmetry. The Moessbauer parameters and ..mu..sub(eff)-value indicate the high spin state of the central iron atom and low spin state for the terminal ones.

  18. Iron(III) species formed during iron(II) oxidation and iron-core formation in bacterioferritin of Escherichia coli

    International Nuclear Information System (INIS)

    Hawkins, C.; Treffry, A.; Mackey, J.; Williams, J.M.; Andrews, S.C.; Guest, J.R.; Harrison, P.M.

    1996-01-01

    This paper describes a preliminary investigation of the mechanisms of Fe(II) oxidation and storage of Fe(III) in the bacterioferritin of Escherichia coli (EcBFR). Using Moessbauer spectroscopy to examine the initial oxidation of iron by EcBFR it is confirmed that this ferritin exhibits 'ferroxidase' activity and is shown that dimeric and monomeric iron species are produced as intermediates. The characteristics of ferroxidase activity in EcBFR is compare d with those of human H-chain ferritin (HuHF) and discuss the different Moessbauer parameters of their dimeric iron with reference to the structures of their di-metal sites. In addition, it is presented preliminary findings suggesting that after an initial 'burst', the rate of oxidation is greatly reduced, possibly due to blockage of the ferroxidase centre by bound iron. A new component, not found in HuHF and probably representing a small cluster of Fe(III) atoms, is reported

  19. Polypyridyl iron(II) complexes showing remarkable photocytotoxicity ...

    Indian Academy of Sciences (India)

    aditya

    Polypyridyl iron(II) complexes showing remarkable photocytotoxicity in visible light. ADITYA GARAI a. , UTTARA BASU a. , ILA PANT b. , PATURU KONDAIAH*. ,b. AND. AKHIL R. CHAKRAVARTY*. ,a a. Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore. 560012, India. E-mail: ...

  20. Toxicological studies and antimicrobial properties of some Iron(III ...

    African Journals Online (AJOL)

    SERVER

    2007-12-17

    Dec 17, 2007 ... Two iron(III) complexes of Ciprofloxacin were synthesized by reaction of the ... The infrared spectra suggest that two classes of compounds were obtained: molecular complex in .... Soluble in H2O, MeOH, EtOH; Mol. cond.

  1. Measuring marine iron(III) complexes by CLE-AdSV

    NARCIS (Netherlands)

    Town, R.M.; Leeuwen, van H.P.

    2005-01-01

    Iron(iii) speciation data, as determined by competitive ligand exchange?adsorptive stripping voltammetry (CLE-AdSV), is reconsidered in the light of the kinetic features of the measurement. The very large stability constants reported for iron(iii) in marine ecosystems are shown to be possibly due to

  2. Kinetics and mechanism of oxidation of glycine by iron(III)

    Indian Academy of Sciences (India)

    Kinetics and mechanism of oxidation of glycine by iron(III)-1,10-phenanthroline complex has been studied in perchloric acid medium. The reaction is first order with respect to iron(III) and glycine. An increase in (phenanthroline) increases the rate, while increase in [H+] decreases the rate. Hence it can be inferred that the ...

  3. Effect of iron(III) ion on moso bamboo pyrolysis under microwave irradiation.

    Science.gov (United States)

    Dong, Qing; Li, Xiangqian; Wang, Zhaoyu; Bi, Yanhong; Yang, Rongling; Zhang, Jinfeng; Luo, Hongzhen; Niu, Miaomiao; Qi, Bo; Lu, Chen

    2017-11-01

    The effect of iron(III) ion on microwave pyrolysis of moso bamboo was investigated. Hydrofluoric acid washing was used as a pilot process to demineralize moso bamboo in order to eliminate the influences of the other inorganics contained in moso bamboo itself. The results indicated that the addition of iron(III) ion increased the maximal reaction temperatures under microwave condition dependent on the amount of the added iron(III) ion. The production of the non-condensable gases was promoted by the addition of iron(III) ion mainly at the expense of liquid products. Iron(III) ion exhibited the positive effect for syngas production and inhibited the formation of CO 2 and CH 4 . The formation of Fe 2 O 3 and Fe 3 O 4 was found during microwave pyrolysis and the mechanism of the two metallic oxides formation was described in this work. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Spin-crossover behavior of polymeric iron(III) complexes

    International Nuclear Information System (INIS)

    Maeda, Yonezo; Miyamoto, Makoto; Takashima, Yoshimasa; Oshio, Hiroaki

    1989-01-01

    Polymeric spin-crossover iron(III) complexes possessing poly(4-vinylpyridine), poly(N-vinylimidazole) or poly(octylmethacrylate-co-4-vinylpyridine) as ligand are prepared. In this experience enriched 57 Fe was used to get strong Moessbauer absorption. The enriched behavior of the complexes were examined by magnetic susceptibilities measurement, and Moessbauer and esr spectroscopies. Some of them show spin-state behavior over a wide range of temperature. Some of them show rapid spin-state interexchange compared to the Moessbauer time scale and others not. Spin-crossover behavior of polymeric complexes is characterized of wide spin-state transition temperature range

  5. Sorption of small amounts of europium(III) on iron(III) hydroxide and oxide

    International Nuclear Information System (INIS)

    Music, S.; Gessner, M.; Wolf, R.H.H.

    1979-01-01

    The sorption of small amounts of europium(III) on iron(III) hydroxide and oxide has been studied as a function of pH. The mechanism of sorption is discussed. Optimum conditions have been found for the preconcentration of small or trace amounts of europium(III) by iron(III) hydroxide and oxide. The influence of complexing agents (EDTA, oxalate, tartrate and 5-sulfosalicylic acid) on the sorption of small amounts of europium(III) on iron(III) oxide has also been studied. (author)

  6. Superconductivity in graphite intercalation compounds

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Robert P. [Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Weller, Thomas E.; Howard, Christopher A. [Department of Physics & Astronomy, University College of London, Gower Street, London WCIE 6BT (United Kingdom); Dean, Mark P.M. [Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Rahnejat, Kaveh C. [Department of Physics & Astronomy, University College of London, Gower Street, London WCIE 6BT (United Kingdom); Saxena, Siddharth S. [Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Ellerby, Mark, E-mail: mark.ellerby@ucl.ac.uk [Department of Physics & Astronomy, University College of London, Gower Street, London WCIE 6BT (United Kingdom)

    2015-07-15

    Highlights: • Historical background of graphite intercalates. • Superconductivity in graphite intercalates and its place in the field of superconductivity. • Recent developments. • Relevant modeling of superconductivity in graphite intercalates. • Interpretations that pertain and questions that remain. - Abstract: The field of superconductivity in the class of materials known as graphite intercalation compounds has a history dating back to the 1960s (Dresselhaus and Dresselhaus, 1981; Enoki et al., 2003). This paper recontextualizes the field in light of the discovery of superconductivity in CaC{sub 6} and YbC{sub 6} in 2005. In what follows, we outline the crystal structure and electronic structure of these and related compounds. We go on to experiments addressing the superconducting energy gap, lattice dynamics, pressure dependence, and how these relate to theoretical studies. The bulk of the evidence strongly supports a BCS superconducting state. However, important questions remain regarding which electronic states and phonon modes are most important for superconductivity, and whether current theoretical techniques can fully describe the dependence of the superconducting transition temperature on pressure and chemical composition.

  7. Superconductivity in graphite intercalation compounds

    International Nuclear Information System (INIS)

    Smith, Robert P.; Weller, Thomas E.; Howard, Christopher A.; Dean, Mark P.M.; Rahnejat, Kaveh C.; Saxena, Siddharth S.; Ellerby, Mark

    2015-01-01

    Highlights: • Historical background of graphite intercalates. • Superconductivity in graphite intercalates and its place in the field of superconductivity. • Recent developments. • Relevant modeling of superconductivity in graphite intercalates. • Interpretations that pertain and questions that remain. - Abstract: The field of superconductivity in the class of materials known as graphite intercalation compounds has a history dating back to the 1960s (Dresselhaus and Dresselhaus, 1981; Enoki et al., 2003). This paper recontextualizes the field in light of the discovery of superconductivity in CaC 6 and YbC 6 in 2005. In what follows, we outline the crystal structure and electronic structure of these and related compounds. We go on to experiments addressing the superconducting energy gap, lattice dynamics, pressure dependence, and how these relate to theoretical studies. The bulk of the evidence strongly supports a BCS superconducting state. However, important questions remain regarding which electronic states and phonon modes are most important for superconductivity, and whether current theoretical techniques can fully describe the dependence of the superconducting transition temperature on pressure and chemical composition

  8. Electrochemistry of Nanostructured Intercalation Hosts

    International Nuclear Information System (INIS)

    Smyrl, William H.

    2009-01-01

    We have shown that: (1) Li+ ions are inserted reversibly, without diffusion control, up to the level of at least 4 moles Li+ ions per mole for V2O5, in the aerogel (ARG) form (500 m2/g specific surface area) and aerogel-like (ARG-L) form (200 m2/g specific surface area)(6,7,1,2); (2) polyvalent cations (Al+3, Mg+2, Zn+2) may be intercalated reversibly into V2O5 (ARG) with high capacity (approaching 4 equivalents/mole V2O5 (ARG)) for each (5); (3) dopant cations such as Ag+ and Cu+2 increase the conductivity of V2O5 (XRG) up to three orders of magnitude(3), they are electrochemically active - showing reduction to the metallic-state in parallel to intercalation of Li+ ions - but are not released to the electrolyte upon oxidation and Li+ ion release (Cu+2 ions are reduced to Cu metal and reoxidized to Cu+2 in Li+ ion insertion/release cycles, but the copper ions are not released to the electrolyte over more than 400 cycles of the XRG form); (4) we have shown that Cu+2 ion (dopant) and Zn+2 ions (chemical insertion and dopant) occupy the same intercalation site inV2O5 xerogel and aerogel(4); and (5) the reversible intercalation of Zn+2, Mg+2, and Al+3 in the ARG(11) indicates that these cations are 'mobile', but that Cu+2 ions and Ag+ ions are 'immobile' in the xerogel, i.e., the latter ions are not exchanged with the electrolyte in Li+ ion intercalation cycling(3).

  9. INTERACTION OF IRON(II MIXED-LIGAND COMPLEXES WITH DNA: BASE-PAIR SPECIFICITY AND THERMAL DENATURATION STUDIES

    Directory of Open Access Journals (Sweden)

    Mudasir Mudasir

    2010-06-01

    Full Text Available A research about base-pair specificity of the DNA binding of [Fe(phen3]2+, [Fe(phen2(dip]2+ and [Fe(phen(dip2]2+ complexes and the effect of calf-thymus DNA (ct-DNA binding of these metal complexes on thermal denaturation of ct-DNA has been carried out. This research is intended to evaluate the preferential binding of the complexes to the sequence of DNA (A-T or G-C sequence and to investigate the binding strength and mode upon their interaction with DNA. Base-pair specificity of the DNA binding of the complexes was determined by comparing the equilibrium binding constant (Kb of each complex to polysynthetic DNA that contain only A-T or G-C sequence. The Kb value of the interaction was determined by spectrophotometric titration and thermal denaturation temperature (Tm was determined by monitoring the absorbance of the mixture solution of each complex and ct-DNA at λ =260 nm as temperature was elevated in the range of 25 - 100 oC. Results of the study show that in general all iron(II complexes studied exhibit a base-pair specificity in their DNA binding to prefer the relatively facile A-T sequence as compared to the G-C one. The thermal denaturation experiments have demonstrated that Fe(phen3]2+ and [Fe(phen2(dip]2+ interact weakly with double helical DNA via electrostatic interaction as indicated by insignificant changes in melting temperature, whereas [Fe(phen2(dip]2+  most probably binds to DNA in mixed modes of interaction, i.e.: intercalation and electrostatic interaction. This conclusion is based on the fact that the binding of [Fe(phen2(dip]2+ to ct-DNA moderately increase the Tm value of ct- DNA   Keywords: DNA Binding, mixed-ligand complexes

  10. HALLOYSITE INTERCALATION OF NORTHWEST ANATOLIA

    Directory of Open Access Journals (Sweden)

    Bülent BAŞARA

    2015-11-01

    Full Text Available In this study, the representative samples were taken from the halloysite deposits located in Çanakkale-Balıkesir regions, in NW Anatolia. At first, the dehydration temperatures of the samples were determined after sample preparation and characterization studies. It was found that halloysite samples began to lose their interlayer waters at 50°C and continued up to 70°C. The intercalation studies were carried out on dehydrated samples by using ethylene glycol, potassium acetate, dimethyl sulfoxide and formamide. Although there were negative results by ethylene glycol and potassium acetate, the satisfactory results were obtained by dimethyl sulfoxide and formamide. It was understood that the most effective reagent in terms of intercalation was formamide.

  11. Intercalation behavior of barium phenylphosphonate

    Czech Academy of Sciences Publication Activity Database

    Beneš, L.; Melánová, Klára; Svoboda, Jan; Zima, Vítězslav

    2010-01-01

    Roč. 71, č. 4 (2010), s. 530-533 ISSN 0022-3697. [15th International Symposium on Intercalation Compounds. Beijing, 11.05.2009-15.05.2009] R&D Projects: GA ČR GA203/08/0208 Institutional research plan: CEZ:AV0Z40500505 Keywords : inorganic compounds * organic compounds * X-ray diffraction Subject RIV: CA - Inorganic Chemistry Impact factor: 1.384, year: 2010

  12. Ammonia from iron(II) reduction of nitrite and the Strecker synthesis: do iron(II) and cyanide interfere with each other?

    Science.gov (United States)

    Summers, D. P.; Lerner, N.

    1998-01-01

    The question of whether the production of ammonia, from the reduction of nitrite by iron(II), is compatible with its use in the Strecker synthesis of amino acids, or whether the iron and the cyanide needed for the Strecker synthesis interfere with each other, is addressed. Results show that the presence of iron(II) appears to have little, or no, effect on the Strecker synthesis. The presence of cyanide does interfere with reduction of nitrite, but the reduction proceeds at cyanide/iron ratios of less than 4:1. At ratios of about 2:1 and less there is only a small effect. The reduction of nitrite and the Strecker can be combined to proceed in each other's presence, to yield glycine from a mixture of nitrite, Fe+2, formaldehyde, and cyanide.

  13. Reaction path sampling of the reaction between iron(II) and hydrogen peroxide in aqueous solution

    NARCIS (Netherlands)

    Ensing, B.; Baerends, E.J.

    2002-01-01

    Previously, we have studied the coordination and dissociation of hydrogen peroxide with iron(II) in aqueous solution by Car-Parrinello molecular dynamics at room temperature. We presented a few illustrative reaction events, in which the ferryl ion ([Fe(IV)O

  14. Photoenhanced Oxidative DNA Cleavage with Non-Heme Iron(II) Complexes

    NARCIS (Netherlands)

    Li, Qian; Browne, Wesley R.; Roelfes, Gerard

    2010-01-01

    The DNA cleavage activity of iron(II) complexes of a series of monotopic pentadentate N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl)methylamine (N4Py)-derived ligands (1-5) was investigated under laser irradiation at 473, 400.8, and 355 nm in the absence of a reducing agent and compared to that under

  15. Interesting properties of some iron(II), copper(I) and copper(II ...

    Indian Academy of Sciences (India)

    Administrator

    Tridendate ligands with nitrogen centers, generally well-known as the tripod ligands, have been of considerable interest to inorganic chemists dealing with the preparation of model compounds for hemocyanin, tyrosinase etc. We have found that such ligands when complexed with iron(II) and copper(II) and copper(I) ions ...

  16. NHC Versus Pyridine: How “Teeth” Change the Redox Behavior of Iron(II) Complexes

    KAUST Repository

    Weiss, Daniel T.; Anneser, Markus R.; Haslinger, Stefan; Pö thig, Alexander; Cokoja, Mirza; Basset, Jean-Marie; Kü hn, Fritz E.

    2015-01-01

    A series of octahedral iron(II) complexes with tetradentate NHC/pyridine hybrid ligands containing up to three pyridyl units was designed to study the influence of NHC and pyridine donors on the electronic structure of the metal center. Structural

  17. Synthesis of thin film containing 4-amino-1,2,4-triazole iron(II) complexes

    Energy Technology Data Exchange (ETDEWEB)

    Onggo, Djulia, E-mail: djulia@Chem.itb.ac.id [Inorganic and Physical Chemistry Research Group, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10 Bandung 40132 (Indonesia)

    2014-03-24

    The Iron(II) complex with 4-amino-1,2,4 triazole (NH{sub 2}-trz) ligand has potential applications as smart material since the compounds show a distinct color change from lilac at low temperature to colorless at high temperature. The lilac color of the complex represent the diamagnetic low spin state while the colorless correspond to the paramagnetic high spin state of iron(II). The transition between the two states could be tuned by changing the anionic group. Generally, the complex was synthesized directly from aqueous solution of iron(II) salt with considerable amounts of NH{sub 2}-trz solution produced solid powder compound. For application as an electronic molecular device, the complex should be obtained as a thin film. The transparent [Fe(NH{sub 2}trz){sub 3}]-Nafion film has been successfully obtained, however, no anion variation can be produced since the nafion is an anionic resin. In this work, the [Fe(NH{sub 2}trz){sub 3}]-complexes with several anions have been synthesized inside nata de coco membrane that commonly used as a medium for deposition metal nano-particles. After drying the membrane containing the complex became a thin film. At room temperature, the film containing iron(II) complexes of sulphate and nitrate salts show lilac color, similar to that of the original complexes in the powder form. On heating, the color of the complex film changed to colorless and this color change was observed reversibly. In contrast, the films containing perchlorate and tetrafluoroborate iron(II) complexes are colorless at room temperature and changed to lilac on cooling. The significant color changing of the iron(II)complexes in the nata de coco film can be used for demonstration thermo chromic effect of smart materials with relatively small amount of the compounds.

  18. Moessbauer spectroscopic studies of alkylammonium iron(III) complexes

    International Nuclear Information System (INIS)

    Katada, M.; Kozawa, S.; Nakajima, Y.

    2006-01-01

    Alkylammonium iron(III) complexes, [(n-C n H 2n+1 )mNH 4-m ] 3 [Fe(CN) 6 ] were prepared and studied by Moessbauer spectroscopy, XRD, and DSC. In the complexes with m=2, the temperature dependences of the area intensity of Moessbauer are correlated to the motion of alkyl chains. The temperature dependence of the complex with n=4 was linear and smaller than that of other complexes. Especially in the complex with n=6, the deviation from the linear was the largest in the complexes observed. This result is attributed to the structural difference of the complex. The complexes with n≥8 consist of two-dimensional layer structure. The temperature dependence of the area intensity was similar to each other. This means that the motion of alkyl chain in these complexes are almost the same. The values of quadrupole splitting for the complexes were larger those that of the complexes (m=1). This indicates that the form of [Fe(CN) 6 ] 3- ion is affected by the differences of the number of alkyl groups. (author)

  19. Intercalation chemistry of zirconium 4-sulfophenylphosphonate

    International Nuclear Information System (INIS)

    Svoboda, Jan; Zima, Vítězslav; Melánová, Klára; Beneš, Ludvík; Trchová, Miroslava

    2013-01-01

    Zirconium 4-sulfophenylphosphonate is a layered material which can be employed as a host for the intercalation reactions with basic molecules. A wide range of organic compounds were chosen to represent intercalation ability of zirconium 4-sulfophenylphosphonate. These were a series of alkylamines from methylamine to dodecylamine, 1,4-phenylenediamine, p-toluidine, 1,8-diaminonaphthalene, 1-aminopyrene, imidazole, pyridine, 4,4′-bipyridine, poly(ethylene imine), and a series of amino acids from glycine to 6-aminocaproic acid. The prepared compounds were characterized by powder X-ray diffraction, thermogravimetry analysis and IR spectroscopy and probable arrangement of the guest molecules in the interlayer space of the host is proposed based on the interlayer distance of the prepared intercalates and amount of the intercalated guest molecules. - Graphical abstract: Nitrogen-containing organic compounds can be intercalated into the interlayer space of zirconium 4-sulfophenylphosphonate. - Highlights: • Zirconium 4-sulfophenylphosphonate was examined as a host material in intercalation chemistry. • A wide range of nitrogen-containing organic compounds were intercalated. • Possible arrangement of the intercalated species is described

  20. Intercalated compounds of niobium and tantalum dicalcogenides

    International Nuclear Information System (INIS)

    Wypych, F.

    1988-01-01

    The synthesis of niobium and tantalum lamellar compounds and its intercalated derivatives is described. The intercalated compounds with lithium, with alkaline metal and with metals of the first-row transition are studied, characterized by X-ray diffraction. (C.G.C.) [pt

  1. Carbon fibers and composites modified by intercalation

    International Nuclear Information System (INIS)

    Macherzynska, B.; Blazewicz, S.

    2002-01-01

    The aim of this paper was to describe ability to intercalation of laboratory prepared carbon composites and their constituents. In work the following materials were tested; pinch-based fibres of P-120 and K-1100 manufacturer's designations, carbon matrix and resulting composites. To prepare a matrix of composites, phenol-formaldehyde resin (Z) and pinch-based precursor (PAK) were used. After initial carbonization, the carbon matrix was heated to 2150 o C i to improve ability to the future intercalation. Three kinds of composites (P/Z, K/Z and K/PAK), with two directional reinforcement (2D), were prepared. All carbon samples were intercalated with copper chloride(II). To study the structure of all materials, before and after intercalation, X-ray diffraction method was used. It enabled to measure microstructure parameters (L c and L a ), interplanar distance (d 002 ) thickness of an intercalation layer (d i ). Before intercalation, graphite fibers are characterized by well developed graphite structure of three-dimensional order, different than carbon turbostratic structures. Graphite fibres show a tendency to intercalation, however this process proceeds harder than in a synthetic graphite, which is testified by diffraction spectra with visible complex stages of intercalation. Comparison of two kinds of graphite fibres show s that their structure significantly affects intercalation process. In the case of composite matrix, a better structure ordering was observed for carbon obtained from PAK than for carbon originating from Z precursor. During production of composites, after the heat treatment (2150 o C), carbon obtained from pyrolysis of Z precursor crystallises on the fibre surface, building a well-developed structure of matrix. The same process occurs during carbonization of pinch-based precursor in presence of graphite fibres. In both cases the composites contain well crystallized graphite phases. The study of carbon composite intercalation shows that the process

  2. Intercalation of lanthanide trichlorides in graphite

    International Nuclear Information System (INIS)

    Stumpp, E.; Nietfeld, G.

    1979-01-01

    The reactions of the whole series of lanthanide trichlorides with graphite have been investigated. Intercalation compounds have been prepared with the chlorides of Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sc, Y whereas LaCl 3 , CeCl 3 , PrCl 3 and NdCl 3 do not intercalate. The compounds were characterized by chemical and X-ray analysis. The amount of c-axis increase is consistent with the assumption that the chlorides are intercalated in form of a chloride layer sandwich resmbling the sheets in YCl 3 . The chlorides which do not intercalate crystallize in the UCl 3 structure having 3 D arrangements of ions. Obviously, these chlorides cannot form sheets between the carbon layers. The ability of AlCl 3 to volatilize lanthanide chlorides through complex formation in the gas phase can be used to increase the intercalation rate strikingly. (author)

  3. Study of Ascorbic Acid as Iron(III Reducing Agent for Spectrophotometric Iron Speciation

    Directory of Open Access Journals (Sweden)

    Antesar Elmagirbi

    2012-10-01

    Full Text Available The study of ascorbic acid as a reducing agent for iron(III has been investigated in order to obtain an alternative carcinogenic reducing agent, hydroxylamine, used in spectrophotometric standard method based on the formation of a red-orange complex of Fe(II-o-phenanthroline. The study was optimised with regards to ascorbic acid concentration as well as pH solution. The results showed that ascorbic acid showed maximum capacity as reducing agent of iron(III under concentration of 4.46.10-4 M and pH solution of 1-4.Under these conditions, ascorbic acid reduced iron(III proportionally and performed similarly to that of hydroxylamine.  The method gave result to linear calibration over the range of 0.2-2 mg/L withhigh accuracy of 97 % and relative standard deviation of less than 2 %. This method was successfully applied to assay iron speciation in water samples.

  4. Large magnetoresistance in intercalated Cu oxides

    OpenAIRE

    Grigoryan, L.; Furusawa, M.; Hori, H.; Tokumoto, M.

    1997-01-01

    Magnetism and electrical resistance as a function of magnetic field, temperature, and chemical composition are studied in Cu oxides intercalated with metal phthalocyanines MPc, where M is Fe or Ni, and Pc is C_H_N_. An unusually large positive magnetoresistance (MR) of ~ 1200% is observed in FePc-intercalated Bi_Sr_Ca_Cu_O_ samples with two Cu-O layers in the unit cell (n=2). The magnitude of the MR decreased to 40% and ~ 0% in the FePc-intercalated n=3 and n=4 samples, respectively, and to ~...

  5. X-ray diffraction study of phase transitions in iron(II) trisnioximate hexadecylboronate clathrochelate complex

    International Nuclear Information System (INIS)

    Vorontsov, I.I.; Antipin, M.Yu.; Dubovik, I.I.; Papkov, V.S.; Potekhin, K.A.; Voloshin, Ya.Z.; Stash, A.I.; Belsky, V.K.

    2001-01-01

    Crystals of the iron(II) nioximate hexadecylboronate clathrochelate complex-FeNx 3 (BHd ) 2 [tris(μ-1,2-cyclohexanedionedioximato-O:O ' )di-n-hexadecyldiborato(2-) - N,'''N''',N''',N''',N''',N ' ]iron(II) - are investigated by differential scanning calorimetry and X-ray diffraction. Two structural phase transitions are revealed at T cr1 = 290(3) K and T cr2 = 190(3) K. The crystal structures of phases I, II, and III are determined by X-ray diffraction analysis at 303, 243, and 153 K, respectively. It is demonstrated that the I ↔ II phase transition is due to a change in the system of translations, and the II ↔ III phase transition is accompanied only by a jumpwise change in the unit cell parameters. The possible mechanisms of phase transitions are discussed in terms of geometry and molecular packing of FeNx 3 (BHd) 2 in all three phases

  6. Iron(II) porphyrins induced conversion of nitrite into nitric oxide: A computational study.

    Science.gov (United States)

    Zhang, Ting Ting; Liu, Yong Dong; Zhong, Ru Gang

    2015-09-01

    Nitrite reduction to nitric oxide by heme proteins was reported as a protective mechanism to hypoxic injury in mammalian physiology. In this study, the pathways of nitrite reduction to nitric oxide mediated by iron(II) porphyrin (P) complexes, which were generally recognized as models for heme proteins, were investigated by using density functional theory (DFT). In view of two type isomers of combination of nitrite and Fe(II)(P), N-nitro- and O-nitrito-Fe(II)-porphyrin complexes, and two binding sites of proton to the different O atoms of nitrite moiety, four main pathways for the conversion of nitrite into nitric oxide mediated by iron(II) porphyrins were proposed. The results indicate that the pathway of N-bound Fe(II)(P)(NO2) isomer into Fe(III)(P)(NO) and water is similar to that of O-bound isomer into nitric oxide and Fe(III)(P)(OH) in both thermodynamical and dynamical aspects. Based on the initial computational studies of five-coordinate nitrite complexes, the conversion of nitrite into NO mediated by Fe(II)(P)(L) complexes with 14 kinds of proximal ligands was also investigated. Generally, the same conclusion that the pathways of N-bound isomers are similar to those of O-bound isomer was obtained for iron(II) porphyrin with ligands. Different effects of ligands on the reduction reactions were also found. It is notable that the negative proximal ligands can improve reactive abilities of N-nitro-iron(II) porphyrins in the conversion of nitrite into nitric oxide compared to neutral ligands. The findings will be helpful to expand our understanding of the mechanism of nitrite reduction to nitric oxide by iron(II) porphyrins. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Bromine intercalated graphite for lightweight composite conductors

    KAUST Repository

    Amassian, Aram; Patole, Archana

    2017-01-01

    A method of fabricating a bromine-graphite/metal composite includes intercalating bromine within layers of graphite via liquid-phase bromination to create brominated-graphite and consolidating the brominated-graphite with a metal nanopowder via a

  8. Fabrication of Li-intercalated bilayer graphene

    Directory of Open Access Journals (Sweden)

    K. Sugawara

    2011-06-01

    Full Text Available We have succeeded in fabricating Li-intercalated bilayer graphene on silicon carbide. The low-energy electron diffraction from Li-deposited bilayer graphene shows a sharp 3×3R30° pattern in contrast to Li-deposited monolayer graphene. This indicates that Li atoms are intercalated between two adjacent graphene layers and take the same well-ordered superstructure as in bulk C6Li. The angle-resolved photoemission spectroscopy has revealed that Li atoms are fully ionized and the π bands of graphene are systematically folded by the superstructure of intercalated Li atoms, producing a snowflake-like Fermi surface centered at the Γ point. The present result suggests a high potential of Li-intercalated bilayer graphene for application to a nano-scale Li-ion battery.

  9. Magnetic resonance studies of intercalation compounds

    International Nuclear Information System (INIS)

    Miller, G.R.

    1990-01-01

    During the last three or four years, nearly tow hundred papers have been published that used NMR or ESR spectroscopy to study compounds formed by the intercalation of molecules or ions into the van der Waals gap of a layered hast compound. The host lattices have ranged from the simple, such as graphite, to the complex, such as clay. In many cases, magnetic resonance techniques now enable one to obtain quite detailed information on even fairly complex intercalated species, on the nature of the changes in the host lattice accompanying intercalation, and on the nature of the interactions between the intercalant species and the host lattice. Magnetic resonance is used in conunction with many other techniques to obtain a fuller picture of these interesting systems, but this review will limit its focus to the use of NMR and ESR techniques. (author). 51 refs

  10. Mononuclear non-heme iron(III) complexes of linear and tripodal ...

    Indian Academy of Sciences (India)

    The rate of oxygenation depends on the solvent and the. Lewis acidity of iron(III) ... has been achieved by non-heme iron enzymes and their ..... oxygen atoms of nitrate ion (figure 3). ... enhanced covalency of iron-catecholate interaction and.

  11. Reply to Comments on Measuring marine iron(III) complexes by CLE-AdSV

    NARCIS (Netherlands)

    Town, R.M.; Leeuwen, van H.P.

    2005-01-01

    The interpretation of CLE-AdSV based iron(iii) speciation data for marine waters has been called into question in light of the kinetic features of the measurement. The implications of the re-think may have consequences for understanding iron biogeochemistry and its impact on ecosystem functioning.

  12. Mechanism of oxidation of L-methionine by iron(III)-1,10 ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Kinetics and mechanism of oxidation of L-methionine by iron(III)–1,10- phenanthroline complex have been studied in perchloric acid medium. The reaction is first order each in iron(III) and methionine. Increase in [phenanthroline] increases the rate while increase in [HClO4] decreases it. While the reactive species ...

  13. Mechanism of oxidation of L-methionine by iron(III)

    Indian Academy of Sciences (India)

    phenanthroline complex have been studied in perchloric acid medium. The reaction is first order each in iron(III) and methionine. Increase in [phenanthroline] increases the rate while increase in [HClO4] decreases it. While the reactive species of the ...

  14. Stabilization through precipitation in a system of colloidal iron(III) pyrophosphate salts

    NARCIS (Netherlands)

    van Leeuwen, Y.M.; Velikov, K.P.; Kegel, W.K.

    2012-01-01

    The ionic strength of a solution decreases during the precipitation of an insoluble salt, which can cause an initially unstable colloidal system to stabilize during its formation. We show this effect in the precipitation and aging of colloidal iron(III) pyrophosphate, where we observe two distinct

  15. Experimental and Computational Evidence for the Mechanism of Intradiol Catechol Dioxygenation by Non-Heme Iron(III) Complexes

    Science.gov (United States)

    Jastrzebski, Robin; Quesne, Matthew G; Weckhuysen, Bert M; de Visser, Sam P; Bruijnincx, Pieter C A

    2014-01-01

    Catechol intradiol dioxygenation is a unique reaction catalyzed by iron-dependent enzymes and non-heme iron(III) complexes. The mechanism by which these systems activate dioxygen in this important metabolic process remains controversial. Using a combination of kinetic measurements and computational modelling of multiple iron(III) catecholato complexes, we have elucidated the catechol cleavage mechanism and show that oxygen binds the iron center by partial dissociation of the substrate from the iron complex. The iron(III) superoxide complex that is formed subsequently attacks the carbon atom of the substrate by a rate-determining C=O bond formation step. PMID:25322920

  16. Ternary iron(II) complex with an emissive imidazopyridine arm from Schiff base cyclizations and its oxidative DNA cleavage activity

    OpenAIRE

    Mukherjee, Arindam; Dhar, Shanta; Nethaji, Munirathinam; Chakravarty, Akhil R

    2005-01-01

    The ternary iron(II) complex [Fe(L')(L")] $(PF_6)_3(1)$ as a synthetic model for the bleomycins, where L' and L" are formed from metal-mediated cyclizations of N,N -(2-hydroxypropane-1,3-diyl)bis(pyridine-2-aldimine)(L), is synthesized and structurally characterized by X-ray crystallography. In the six-coordinate iron(II) complex, ligands L' and L" show tetradentate and bidentate chelating modes of bonding. Ligand L' is formed from an intramolecular attack of the alcoholic OH group of L to o...

  17. Sulphate analysis in uranium leach iron(III) chloride solutions by inductively coupled argon plasma spectrometry

    International Nuclear Information System (INIS)

    Nirdosh, I.; Lakhani, S.; Yunus, M.Z.M.

    1993-01-01

    Inductively coupled Argon Plasma Spectrometry is used for the indirect determination of sulphate in iron(III) chloride leach solution of Elliot Lake uranium ores via addition of a known amount of barium ions and analyzing for excess of barium. The ore contains ∼ 7 wt% pyrite, FeS 2 , as the major mineral which oxidizes to generate sulphate during leaching with Fe(III). The effects of pH, the concentrations of Fe(III) and chloride ions and for presence of ethanol in the test samples on the accuracy of analysis are studied. It is found that unlike the Rhodizonate method, removal of iron(III) from or addition of ethanol to the test sample prior to analysis are not required. Linear calibration curves are obtained. (author)

  18. Quasi-freestanding graphene on Ni(111) by Cs intercalation

    KAUST Repository

    Alattas, Maha Hassan Mohssen; Schwingenschlö gl, Udo

    2016-01-01

    A possible approach to achieve quasi-freestanding graphene on a substrate for technological purpose is the intercalation of alkali metal atoms. Cs intercalation between graphene and Ni(111) therefore is investigated using density functional theory

  19. Quasi-freestanding graphene on Ni(111) by Cs intercalation

    KAUST Repository

    Alattas, Maha Hassan Mohssen; Schwingenschlö gl, Udo

    2017-01-01

    It is of technological interest to achieve quasi-freestanding graphene on a substrate. A possible approach is the intercalation of alkali metal atoms. Cs intercalation between graphene and Ni(111) is investigated using density functional theory

  20. Moessbauer study of some iron(II) complexes with methyl isocyanide, bipyridine and phenanthroline

    Energy Technology Data Exchange (ETDEWEB)

    Calogero, S [Consiglio Nazionale delle Ricerche, Padua (Italy). Lab. di Chimica e Tecnologia dei Radioelementi; Russo, U [Padua Univ. (Italy). Istituto di Chimica Generale ed Inorganica e di Chimica Inorganica Industriale; Fragala, I [Catania Univ. (Italy). Istituto di Chimica Generale

    1979-06-01

    Moessbauer parameters for hexacoordinate iron(II) complexes of the type (Fe(N-N)sub(n)(CNMe)sub(m)) (ClO/sub 4/)/sub 2/(m=6, 4, 2 or 0; n=0, 1, 2 or 3; N-N=2.2'-bipyridine or 1.10-phenanthroline) have been determined. Treatment by a point-charge model including distortions has been carried out in order to rationalize the quadrupole splittings. A computer program has been developed to handle variable geometry systems.

  1. Biomimetic oxidation of piperine and piplartine catalyzed by iron(III) and manganese(III) porphyrins.

    Science.gov (United States)

    Schaab, Estela Hanauer; Crotti, Antonio Eduardo Miller; Iamamoto, Yassuko; Kato, Massuo Jorge; Lotufo, Letícia Veras Costa; Lopes, Norberto Peporine

    2010-01-01

    Synthetic metalloporphyrins, in the presence of monooxygen donors, are known to mimetize various reactions of cytochrome P450 enzymes systems in the oxidation of drugs and natural products. The oxidation of piperine and piplartine by iodosylbenzene using iron(III) and manganese(III) porphyrins yielded mono- and dihydroxylated products, respectively. Piplartine showed to be a more reactive substrate towards the catalysts tested. The structures of the oxidation products were proposed based on electrospray ionization tandem mass spectrometry.

  2. Microbial dissimilatory iron(III) reduction: Studies on the mechanism and on processes of environmental relevance

    OpenAIRE

    Jahn, Michael

    2005-01-01

    Many microbes are able to respire aerobically oxygen or anaerobically other electron acceptors for example sulphate, nitrate, manganese(IV) or Fe(III). As iron minerals are widespread in nature, dissimilatory iron(III) reduction by different microorganisms is a very important process of anaerobic respiration. The general goal of this work was to improve the knowledge of processes, in which iron-reducing microbes are said to play an important role. For this purpose, in one part the focus wa...

  3. Ion-Selective Electrode for the Determination of Iron(III in Vitamin Formulations

    Directory of Open Access Journals (Sweden)

    Teixeira Marcos Fernando de S.

    1998-01-01

    Full Text Available A coated graphite-epoxy ion-selective electrode for iron(III, based on the ion-pair formed between [Fe(citrate2]3- and the tricaprylylmethylammonium cation (Aliquat 336 in a poly(vinylchloride (PVC matrix has been constructed. A thin membrane film of this ion-pair, dibutylphthalate (DBPh in PVC was deposited directly onto a Perspex® tube, which contained a graphite-epoxy conductor substrate. The coating solution was prepared by dissolving 30% (w/w of PVC in 10 mL of tetrahydrofuran following addition of 65% (w/w DBPh and 5% (w/w of the ionic pair. The effect of pH, citrate concentration and some cations on the electrode response has been investigated. The E(mV vs. log [Fe(citrate2]3- electrode response was linear for iron(III concentration from 1.0 x 10-3 mol/L to 1.0 x 10-1 mol/L in 1.0 mol/L citrate medium, with a slope of 19.3 ± 0.5 mV/decade and a useful lifetime of at least six months (more than 800 determinations for each polymeric membrane used. The detection limit was 7.5 x 10-4 mol/L and the relative standard deviation was less than 3% for a solution containing 5.0 x 10-3 mol/L of iron(III (n = 10. The application of this electrode for iron(III determination in samples of vitamin formulations is described. The results obtained with this procedure are in close agreement with those obtained using AA spectrophotometry (r = 0.9999.

  4. Application of sorption method on hydroxides for purification of some reactive from iron(III) markings

    International Nuclear Information System (INIS)

    Rakhmonberdiev, A.D.; Khamidov, B.O.

    1986-01-01

    The method of purification of solutions of citric acid, tartaric acid and their salts, potassium hydroxide, potassium nitrate and chloride, sodium perchlorate from iron (III) impurities by means of sorption method on zirconium hydroxide is elaborated. The control of iron(III) content in solutions is conducted by inversion voltammetry method with mercury-graphite electrode. It is defined that complete sorption of iron (III) ions achieves at ph =4÷14.

  5. Disproportionation of hydroxylamine by water-soluble iron(III) porphyrinate compounds.

    Science.gov (United States)

    Bari, Sara E; Amorebieta, Valentín T; Gutiérrez, María M; Olabe, José A; Doctorovich, Fabio

    2010-01-01

    The reactions of hydroxylamine (HA) with several water-soluble iron(III) porphyrinate compounds, namely iron(III) meso-tetrakis-(N-ethylpyridinium-2yl)-porphyrinate ([Fe(III)(TEPyP)](5+)), iron(III) meso-tetrakis-(4-sulphonatophenyl)-porphyrinate ([Fe(III)(TPPS)](3-)), and microperoxidase 11 ([Fe(III)(MP11)]) were studied for different [Fe(III)(Porph)]/[HA] ratios, under anaerobic conditions at neutral pH. Efficient catalytic processes leading to the disproportionation of HA by these iron(III) porphyrinates were evidenced for the first time. As a common feature, only N(2) and N(2)O were found as gaseous, nitrogen-containing oxidation products, while NH(3) was the unique reduced species detected. Different N(2)/N(2)O ratios obtained with these three porphyrinates strongly suggest distinctive mechanistic scenarios: while [Fe(III)(TEPyP)](5+) and [Fe(III)(MP11)] formed unknown steady-state porphyrinic intermediates in the presence of HA, [Fe(III)(TPPS)](3-) led to the well characterized soluble intermediate, [Fe(II)(TPPS)NO](4-). Free-radical formation was only evidenced for [Fe(III)(TEPyP)](5+), as a consequence of a metal centered reduction. We discuss the catalytic pathways of HA disproportionation on the basis of the distribution of gaseous products, free radicals formation, the nature of porphyrinic intermediates, the Fe(II)/Fe(III) redox potential, the coordinating capabilities of each complex, and the kinetic analysis. The absence of NO(2)(-) revealed either that no HAO-like activity was operative under our reaction conditions, or that NO(2)(-), if formed, was consumed in the reaction milieu.

  6. Radiochemical study of the sorption of iodate ions on iron(III) hydroxide precipitate

    International Nuclear Information System (INIS)

    Music, S.; Sipalo-Zuljevic, J.; Wolf, R.H.H.

    1980-01-01

    The sorption of iodate ions on iron(III) hydroxide in dependence on the pH, the aging time of the precipitate and the duration of the contact between the sorbate and the sorbent have been studied. Na 131 IO 3 was used as a radioactive indicator. The sorption mechanism has been discussed in terms of electrostatic and ion-exchange processes at the solid/liquid interface. (author)

  7. Reactivity of tris(acetylacetonato) iron(III) with tridentate [ONO] donor Schiff base as an access to newer mixed-ligand iron(III) complexes

    Science.gov (United States)

    Bhattacharjee, Chira R.; Goswami, Pankaj; Pramanik, Harun A. R.; Paul, Pradip C.; Mondal, Paritosh

    2011-05-01

    Two new mixed-ligand iron(III) complexes, [Fe(L n)(acac)(C 2H 5OH)] incorporating coordinated ethanol from the reaction solvent were accessed from the reaction of [Fe(acac) 3] with [ONO] donor dibasic tridentate unsymmetrical Schiff base ligands derived from condensation of 2-hydroxy-1-napthaldehyde with 2-aminophenol (H 2L 1) or 2-aminobenzoic acid (H 2L 2). The thermal study (TGA-DTA) provided evidence for weakly bound ethanol which is readily substituted by neutral N-donor molecule imidazole, benzimidazole or pyridine to produce an array of newer complexes, [Fe(L n)(acac)X] ( n = 1, 2; X = Im, Bim, Py). The compounds were characterized by elemental analyses, FT-IR, UV-vis, solution electrical conductivity, FAB mass, 1H and 13C NMR spectroscopy. Room temperature magnetic susceptibility measurements ( μeff ˜ 5.8 B.M.) are consistent with spin-free octahedral iron(III) complexes. Cyclic voltammetry of ethanol complexes revealed a quasi-reversible one electron redox response (Δ Ep > 100 mV) for the Fe(III)/Fe(II) couple. Low half wave redox potential ( E1/2) values suggested easy redox susceptibility. The ground state geometries of the ethanol and imidazole complexes have been ascertained to be distorted octahedral by density functional theory using DMol3 program at BLYP/DNP level.

  8. Superlattice Effects in Graphite Intercalation Compounds.

    Science.gov (United States)

    1986-04-15

    away from ;le[ Isy.st,.mns (r lin( nl :; atars ) and look for nonlinear dynamical effects -. m,,5,: U~ i,: ,1 : s y’t, rns, a3iioh m i Josephson...Intercalation Coaanm, Chemistry Dept., Northeast(.rn,, February 25, 1935. ( iv) "Giant Magnetic Interaction and Domain Dynamics in Twe -. "Dimensions," hoston

  9. Selective coal mining of intercalated lignite deposits

    Energy Technology Data Exchange (ETDEWEB)

    Zunic, R [Kolubara-Projekt, Lazarevac (Yugoslavia)

    1991-01-01

    Describes selective coal mining in the Tamnava-Istocno Polje coal surface coal mine (Yugoslavia), designed for an annual coal production of 11.4 Mt. Until 1991, this mine exploited one thick lignite seam, without spoil intercalations, using a bucket wheel excavator-conveyor-spreader system both for coal mining and removal of overburden. In the future, several spoil intercalations of up to 1.0 m and thicker will appear with a total volume of 22 million m{sup 3}. These intercalations have to be selectively excavated in order to guarantee the calorific value of coal for the Nikola Tesla power plant. Computer calculations were carried out to determine the decrease in excavator coal production due to selective mining of spoil strata. Calculations found that the annual surface mine capacity will be lower by at most 9%, depending on thickness of spoil intercalations. The useful operation time of excavators will be reduced by 98 hours per year. The planned annual coal production will nevertheless be fulfilled. 3 refs.

  10. clay nanocomposite by solution intercalation technique

    Indian Academy of Sciences (India)

    Polymer–clay nanocomposites of commercial polystyrene (PS) and clay laponite were prepared via solution intercalation technique. Laponite was modified suitably with the well known cationic surfactant cetyltrimethyl ammonium bromide by ion-exchange reaction to render laponite miscible with hydrophobic PS.

  11. Hydrothermal synthesis of a new ethylenediammonium intercalated ...

    Indian Academy of Sciences (India)

    Unknown

    Vanadyl phosphate; hydrothermal synthesis; intercalation; single crystal ... presence of 'en'.7–15 In all these solids en molecules occur in suitable ... all the cases, the mixture was transferred to a 45 ml Teflon lined Parr acid digestion .... position cannot be fully occupied at the same time as it will lead to a P-P distance of.

  12. Intercalation of Toluidines into Alpha - Zirconium Hydrogenphosphate

    Czech Academy of Sciences Publication Activity Database

    Beneš, L.; Melánová, Klára; Svoboda, Jan; Zima, Vítězslav

    2006-01-01

    Roč. 55, č. 3-4 (2006), s. 289-293 ISSN 0923-0750 R&D Projects: GA ČR(CZ) GA203/05/2306 Institutional research plan: CEZ:AV0Z40500505 Keywords : intercalation Subject RIV: CA - Inorganic Chemistry Impact factor: 1.251, year: 2006

  13. Bromine intercalated graphite for lightweight composite conductors

    KAUST Repository

    Amassian, Aram

    2017-07-20

    A method of fabricating a bromine-graphite/metal composite includes intercalating bromine within layers of graphite via liquid-phase bromination to create brominated-graphite and consolidating the brominated-graphite with a metal nanopowder via a mechanical pressing operation to generate a bromine-graphite/metal composite material.

  14. Preservation of iron(II) by carbon-rich matrices in a hydrothermal plume

    Energy Technology Data Exchange (ETDEWEB)

    Toner, Brandy M.; Fakra, Sirine C.; Manganini, Steven J.; Santelli, Cara M.; Marcus, Matthew A.; Moffett, James W.; Rouxel, Olivier; German, Christopher R.; Edwards, Katrina J.

    2008-09-20

    Hydrothermal venting associated with mid-ocean ridge volcanism is globally widespread. This venting is responsible for a dissolved iron flux to the ocean that is approximately equal to that associated with continental riverine runoff. For hydrothermal fluxes, it has long been assumed that most of the iron entering the oceans is precipitated in inorganic forms. However, the possibility of globally significant fluxes of iron escaping these mass precipitation events and entering open-ocean cycles is now being debated, and two recent studies suggest that dissolved organic ligands might influence the fate of hydrothermally vented metals. Here we present spectromicroscopic measurements of iron and carbon in hydrothermal plume particles at the East Pacific Rise mid-ocean ridge. We show that organic carbon-rich matrices, containing evenly dispersed iron(II)-rich materials, are pervasive in hydrothermal plume particles. The absence of discrete iron(II) particles suggests that the carbon and iron associate through sorption or complexation. We suggest that these carbon matrices stabilize iron(II) released from hydrothermal vents in the region, preventing its oxidation and/or precipitation as insoluble minerals. Our findings have implications for deep-sea biogeochemical cycling of iron, a widely recognized limiting nutrient in the oceans.

  15. Mechanism of redox reactions induced by light and electron pulse in solutions of mixed ligand iron(II) complex cyanides

    International Nuclear Information System (INIS)

    Horvath, A.; Szoeke, J.; Wojnarovits, L.

    1991-01-01

    Redox reactions induced by light and electron pulse have been studied in aqueous solutions of mixed ligand iron(II) complex cyanides. The short lived intermediates have been identified by time resolved specroscopy, the results of detailed kinetic analysis have been discussed. (author) 6 refs.; 3 figs.; 2 tabs

  16. Inorganic arsenic and iron(II) distributions in sediment porewaters investigated by a combined DGTcolourimetric DET technique

    DEFF Research Database (Denmark)

    Bennett, William W.; Teasdale, Peter R.; Welsh, David T.

    2012-01-01

    A new approach for investigating the biogeochemistry of inorganic arsenic and iron(II) in freshwater, estuarine and marine sediments is reported. The recently developed Metsorb diffusive gradients in thin films (DGT) technique for the measurement of total inorganic arsenic and the colourimetric d...... highly representative assessment of the biogeochemical status of arsenic and iron in a variety of natural sediments, including groundwater sediments where mobilised arsenic is responsible for significant human health risks.......A new approach for investigating the biogeochemistry of inorganic arsenic and iron(II) in freshwater, estuarine and marine sediments is reported. The recently developed Metsorb diffusive gradients in thin films (DGT) technique for the measurement of total inorganic arsenic and the colourimetric...... diffusive equilibration in thin films (DET) technique for the measurement of iron(II), were utilised in combination to determine co-located depth profiles of both solutes in sediment porewaters. DGT-measured porewater arsenic concentrations were typically less than 40nM, whereas iron(II) concentrations...

  17. Synthesis, characterization, and reactivity of furan- and thiophene-functionalized bis(n-heterocyclic carbene) complexes of iron(II)

    KAUST Repository

    Rieb, Julia; Raba, Andreas; Haslinger, Stefan; Kaspar, Manuel; Pö thig, Alexander; Cokoja, Mirza; Basset, Jean-Marie; Kü hn, Fritz

    2014-01-01

    The synthesis of iron(II) complexes bearing new heteroatom-functionalized methylene-bridged bis(N-heterocyclic carbene) ligands is reported. All complexes are characterized by single-crystal X-ray diffraction (SC-XRD), nuclear magnetic resonance

  18. Adsorption Characteristics of Different Adsorbents and Iron(III Salt for Removing As(V from Water

    Directory of Open Access Journals (Sweden)

    Josip Ćurko

    2016-01-01

    Full Text Available The aim of this study is to determine the adsorption performance of three types of adsorbents for removal of As(V from water: Bayoxide® E33 (granular iron(III oxide, Titansorb® (granular titanium oxide and a suspension of precipitated iron(III hydroxide. Results of As(V adsorption stoichiometry of two commercial adsorbents and precipitated iron(III hydroxide in tap and demineralized water were fitted to Freundlich and Langmuir adsorption isotherm equations, from which adsorption constants and adsorption capacity were calculated. The separation factor RL for the three adsorbents ranged from 0.04 to 0.61, indicating effective adsorption. Precipitated iron(III hydroxide had the greatest, while Titansorb had the lowest capacity to adsorb As(V. Comparison of adsorption from tap or demineralized water showed that Bayoxide and precipitated iron(III hydroxide had higher adsorption capacity in demineralized water, whereas Titansorb showed a slightly higher capacity in tap water. These results provide mechanistic insights into how commonly used adsorbents remove As(V from water.

  19. Chemical state analysis of iron(III) compounds precipitated homogeneously from solutions containing urea by means of Moessbauer spectrometry and x-ray diffractometry

    International Nuclear Information System (INIS)

    Ujihira, Yusuke; Ohyabu, Matashige; Murakami, Tetsuro; Horie, Tsuyoshi.

    1978-01-01

    Chemical states of iron(III) compounds, precipitated homogeneously by heating the iron(III) salt solution at 363 K in the presence of urea, was studied by means of Moessbauer spectrometry and X-ray diffractometry. The pH-time relation of urea hydrolysis revealed that the precipitation process from homogeneous solution is identical to the hydrolysis of iron(III) ion at pH around 2 under the homogeneous supply of OH - ion, which is generated by hydrolysis of urea. Accordingly, iron(III) oxide hydroxide or similar compounds to the hydrolysis products of iron(III) ion was precipitated by the precipitation from homogeneous solution methods. Akaganeite (β-FeOOH) was crystallized from 0.1 M iron(III) chloride solution. Goethite(α-FeOOH) and hematite(α-Fe 2 O 3 ) was precipitated from 0.1 M iron(III) nitrate solution, vigorous liberation of OH - ion favoring the crystallization of hematite. The addition of chloride ion to the solution resulted in the formation of akaganeite. Basic salt of iron sulfate[NH 4 Fe 3 (OH) 6 (SO 4 ) 2 ] and goethite were formed from 0.1 M iron(III) sulfate solution, the former being obtained in the more moderate condition of the urea hydrolysis ( 363 K). (author)

  20. Oxygen reduction reaction at MWCNT-modified nanoscale iron(II) tetrasulfophthalocyanine: remarkable performance over platinum and tolerance toward methanol in alkaline medium

    CSIR Research Space (South Africa)

    Fashedemi, OO

    2015-04-01

    Full Text Available A nanoscale iron(II) tetrasulfophthalocyanine (nanoFeTSPc) catalyst obtained by co-ordinating with hexadecyltrimethylammonium bromide and subsequently anchored onto multi-walled carbon nanotubes (MWCNTs) for oxygen reduction reaction (ORR) has been...

  1. Phonon studies of intercalated conductive polymers

    Energy Technology Data Exchange (ETDEWEB)

    Prassides, K; Bell, C J [School of Chemistry and Molecular Sciences, Univ. of Sussex, Brighton (United Kingdom); Dianoux, A J [Inst. Laue-Langevin, 38 - Grenoble (France); Chunguey, Wu; Kanatzidis, M G [Dept. of Chemistry, Michigan State Univ., East Lansing (United States)

    1992-06-01

    The phonon density-of-states of FeOCl, the conductive form of polyaniline and the intercalation compound (polyaniline)[sub 0.20]FeOCl(I) have been measured by the neutron time-of-flight technique. The results are discussed in the light of the conducting and structural properties of the materials. Compound I is oxidised by standing in air and the neutron measurements reveal substantial changes in the inorganic host skeleton. (orig.).

  2. Different arsenate and phosphate incorporation effects on the nucleation and growth of iron(III) (Hydr)oxides on quartz.

    Science.gov (United States)

    Neil, Chelsea W; Lee, Byeongdu; Jun, Young-Shin

    2014-10-21

    Iron(III) (hydr)oxides play an important role in the geochemical cycling of contaminants in natural and engineered aquatic systems. The ability of iron(III) (hydr)oxides to immobilize contaminants can be related to whether the precipitates form heterogeneously (e.g., at mineral surfaces) or homogeneously in solution. Utilizing grazing incidence small-angle X-ray scattering (GISAXS), we studied heterogeneous iron(III) (hydr)oxide nucleation and growth on quartz substrates for systems containing arsenate and phosphate anions. For the iron(III) only system, the radius of gyration (Rg) of heterogeneously formed precipitates grew from 1.5 to 2.5 (± 1.0) nm within 1 h. For the system containing 10(-5) M arsenate, Rg grew from 3.6 to 6.1 (± 0.5) nm, and for the system containing 10(-5) M phosphate, Rg grew from 2.0 to 4.0 (± 0.2) nm. While the systems containing these oxyanions had more growth, the system containing only iron(III) had the most nucleation events on substrates. Ex situ analyses of homogeneously and heterogeneously formed precipitates indicated that precipitates in the arsenate system had the highest water content and that oxyanions may bridge iron(III) hydroxide polymeric embryos to form a structure similar to ferric arsenate or ferric phosphate. These new findings are important because differences in nucleation and growth rates and particle sizes will impact the number of available reactive sites and the reactivity of newly formed particles toward aqueous contaminants.

  3. Theological Implications of Markan Interpretative Intercalations

    Directory of Open Access Journals (Sweden)

    Mateusz Kusio

    2015-09-01

    Full Text Available This paper aims at evidencing the thesis that Markan interpretative intercalations are a narrative structure that manifests profound theological engagement of the evangelist. This device is defined as an entanglement of two storylines in the A1–B–A2 pattern which by using the notions of simultaneity, contrast, irony, similarity, etc. offers a wholly novel meaning of the stories. Six intercalations of the St Mark’s gospel – 3 : 20–35; 5 : 21–43; 6 : 7–31; 11 : 12–23; 14 : 1–11, 53–72 – merge different episodes with distinct theological purposes and as such cannot be reduced to the rank of a literary or redactional device. All of them are concerned with the most essential topics of the Markan theology, such as Christology, especially in relation to suffering, requirements of true discipleship, vision of the future ecclesiastical community. St Mark in his intercalations reveals his elaborated, clear-cut theology, as well as narrative ingenuity and mastery.

  4. Structure and Magnetic Properties of a Dodecanuclear Twisted-Ring Iron(III) Cluster.

    Science.gov (United States)

    Caneschi, Andrea; Cornia, Andrea; Fabretti, Antonio C; Gatteschi, Dante

    1999-05-03

    An unprecedented nonplanar structure characterizes the complex [Fe(OCH 3 ) 2 (dbm)] 12 (on the left in the picture), which contains the largest cyclic ferric cluster yet reported with chemically equivalent bridging units. It is made up of twelve high-spin, antiferromagnetically coupled iron(III) centers and neatly reacts with Na I or Li I templates in organic solution to give hexairon(III) coronates (right). Fe=•, O=○, NaI or LiI=• Hdbm=dibenzoylmethane. © 1999 WILEY-VCH Verlag GmbH, Weinheim, Fed. Rep. of Germany.

  5. Sorption of microamount of colloidal silver iodide on hydrated iron(III) oxide

    International Nuclear Information System (INIS)

    Kepak, F.; Nova, J.

    1975-01-01

    Sorption of a microamount of colloidal silver iodide labelled with 131 I on hydrated iron/III/ oxide suspension was studied. The sorption dependence upon pH, sorbent amount, and inert electrolyte concentration has revealed that sorption of silver iodide reaches no more than 63%. The sorption lasted one hour during which the maximum value was reached. Desorption time was one hour, as well. Except for measuring the sorption dependence on pH, the sorption pH was 7.0, temperature 24+-2 0 C. (F.G.)

  6. Saline-water bioleaching of chalcopyrite with thermophilic, iron(II)- and sulfur-oxidizing microorganisms.

    Science.gov (United States)

    Watling, Helen R; Collinson, David M; Corbett, Melissa K; Shiers, Denis W; Kaksonen, Anna H; Watkin, Elizabeth L J

    2016-09-01

    The application of thermoacidophiles for chalcopyrite (CuFeS2) bioleaching in hot, acidic, saline solution was investigated as a possible process route for rapid Cu extraction. The study comprised a discussion of protective mechanisms employed for the survival and/or adaptation of thermoacidophiles to osmotic stress, a compilation of chloride tolerances for three genera of thermoacidophiles applied in bioleaching and an experimental study of the activities of three species in a saline bioleaching system. The data showed that the oxidation rates of iron(II) and reduced inorganic sulfur compounds (tetrathionate) were reduced in the presence of chloride levels well below chloride concentrations in seawater, limiting the applicability of these microorganisms in the bioleaching of CuFeS2 in saline water. Copyright © 2016. Published by Elsevier Masson SAS.

  7. Determination of plutonium by secondary coulometric titration with internally generated iron(II) Pt. 2

    International Nuclear Information System (INIS)

    Chitnis, R.T.; Talnikar, S.G.; Thakur, V.A.; Paranjape, A.H.

    1979-01-01

    Determination of plutonium by secondary coulometry involving the controlled potential technique for the generation of an iron(II) mediator, is reported in Part I. In this paper, the same determination is reported using constant current coulometry for the generation of the mediator, and zero current potentiometry for end-point detection. The factors affecting the current efficiency, viz. current density and supporting electrolyte composition have been checked in order to define the appropriate conditions for obtaining 100% current efficiency. The original method of Carson et al. suffers from the disadvantage that it involves complicated sample treatment. Introduction of perchloric acid treatment as a method for the oxidation of plutonium and the pretitration of the supporting electrolyte to the end-point potential prior to sample addition, have considerably helped to improve the precision and accuracy of the method. Exhaustive analytical data are reported covering plutonium quantities ranging from 25 micrograms to 5 milligrams, which establishes the scope of the method. (author)

  8. NHC Versus Pyridine: How “Teeth” Change the Redox Behavior of Iron(II) Complexes

    KAUST Repository

    Weiss, Daniel T.

    2015-10-06

    A series of octahedral iron(II) complexes with tetradentate NHC/pyridine hybrid ligands containing up to three pyridyl units was designed to study the influence of NHC and pyridine donors on the electronic structure of the metal center. Structural analysis of the iron complexes by NMR spectroscopy and single-crystal X-ray diffraction reveals different coordination modes of the ligand depending on the linkage of the different donor moieties. The oxidation potentials of all complexes correlate linearly with the number of NHC moieties coordinated to iron, as shown by cyclic voltammetry. The influence, although minor, of structural properties on the oxidation potential and (in one case) the influence of the oxidation state of the coordination geometry of the hybrid ligand are also demonstrated.

  9. Charge carrier density in Li-intercalated graphene

    KAUST Repository

    Kaloni, Thaneshwor P.

    2012-05-01

    The electronic structures of bulk C 6Li, Li-intercalated free-standing bilayer graphene, and Li-intercalated bilayer and trilayer graphene on SiC(0 0 0 1) are studied using density functional theory. Our estimate of Young\\'s modulus suggests that Li-intercalation increases the intrinsic stiffness. For decreasing Li-C interaction, the Dirac point shifts to the Fermi level and the associated band splitting vanishes. For Li-intercalated bilayer graphene on SiC(0 0 0 1) the splitting at the Dirac point is tiny. It is also very small at the two Dirac points of Li-intercalated trilayer graphene on SiC(0 0 0 1). For all the systems under study, a large enhancement of the charge carrier density is achieved by Li intercalation. © 2012 Elsevier B.V. All rights reserved.

  10. Synthesis and stability of Br2, ICl and IBr intercalated pitch-based graphite fibers

    Science.gov (United States)

    Wessbecher, Dorothy E.; Forsman, William C.; Gaier, James R.

    1988-01-01

    The intercalation of halogens in pitch-based fiber is studied as well as the stability of the resultant intercalation compounds. It is found that IBr intercalates P-100 to yield a high-sigma GIC with attractive stability properties. During ICl intercalation, the presence of O2 interferes with the reaction and necessitates a higher threshold pressure for intercalation.

  11. The intercalation chemistry of layered iron chalcogenide superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Vivanco, Hector K.; Rodriguez, Efrain E., E-mail: efrain@umd.edu

    2016-10-15

    The iron chalcogenides FeSe and FeS are superconductors composed of two-dimensional sheets held together by van der Waals interactions, which makes them prime candidates for the intercalation of various guest species. We review the intercalation chemistry of FeSe and FeS superconductors and discuss their synthesis, structure, and physical properties. Before we review the latest work in this area, we provide a brief background on the intercalation chemistry of other inorganic materials that exhibit enhanced superconducting properties upon intercalation, which include the transition metal dichalcogenides, fullerenes, and layered cobalt oxides. From past studies of these intercalated superconductors, we discuss the role of the intercalates in terms of charge doping, structural distortions, and Fermi surface reconstruction. We also briefly review the physical and chemical properties of the host materials—mackinawite-type FeS and β-FeSe. The three types of intercalates for the iron chalcogenides can be placed in three categories: 1.) alkali and alkaline earth cations intercalated through the liquid ammonia technique; 2.) cations intercalated with organic amines such as ethylenediamine; and 3.) layered hydroxides intercalated during hydrothermal conditions. A recurring theme in these studies is the role of the intercalated guest in electron doping the chalcogenide host and in enhancing the two-dimensionality of the electronic structure by spacing the FeSe layers apart. We end this review discussing possible new avenues in the intercalation chemistry of transition metal monochalcogenides, and the promise of these materials as a unique set of new inorganic two-dimensional systems.

  12. Reaction of nitriles intercalation in tantalum pentachloride complexes with amines

    International Nuclear Information System (INIS)

    Glushkova, M.A.; Chumaevskij, N.A.; Khmelevskaya, L.V.; Ershova, M.M.; Buslaev, Yu.A.

    1987-01-01

    Data on the study of aceto-, propio- and benzonitrile intercalation in TaCl 5 complexes with diethyl- and triethylamines in CCl 4 solution are discussed. Using the methods of IR and Raman spectroscopy it has been established that it is the nature of ligand, and not nitrile intercalated in the complex, that affects greatly the composition of final products. In contrast to acetonitrile, intercalation in the complex of propio- and benzonitriles is observed already at room temperature. On the basis of spectral data a supposition is made that carbon tetrachloride used as a solvent accelerates the reaction of nitrile intercalation and promotes their deprotonation in the presence of aprotonic amine

  13. Superconductivity of TiNCl intercalated with diamines

    International Nuclear Information System (INIS)

    Yamanaka, Shoji; Umemoto, Keita

    2010-01-01

    Intercalation compounds of TiNCl with ethylenediamine (EDA) and hexamethylenediamine (HDA) were prepared. The basal spacing of TiNCl increased by 3.3-3.9 A upon intercalation, implying that the molecules are lying with the alkyl chains parallel to the TiNCl layers in both compounds. The intercalated compounds showed superconductivity with transition temperatures (T c s) of 10.5 and 15.5 K for EDA and HDA, respectively, which are higher than 8.6 K of pyridine (Py) intercalated compound, Py 0.25 TiNCl.

  14. Superconductivity of TiNCl intercalated with diamines

    Energy Technology Data Exchange (ETDEWEB)

    Yamanaka, Shoji, E-mail: syamana@hiroshima-u.ac.j [Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima 739-8527 (Japan); Umemoto, Keita [Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima 739-8527 (Japan)

    2010-12-15

    Intercalation compounds of TiNCl with ethylenediamine (EDA) and hexamethylenediamine (HDA) were prepared. The basal spacing of TiNCl increased by 3.3-3.9 A upon intercalation, implying that the molecules are lying with the alkyl chains parallel to the TiNCl layers in both compounds. The intercalated compounds showed superconductivity with transition temperatures (T{sub c}s) of 10.5 and 15.5 K for EDA and HDA, respectively, which are higher than 8.6 K of pyridine (Py) intercalated compound, Py{sub 0.25}TiNCl.

  15. Direct synthesis of magnetite nanoparticles from iron(II) carboxymethylcellulose and their performance as NMR contrast agents

    Energy Technology Data Exchange (ETDEWEB)

    Gomes da Silva, Delmarcio; Hiroshi Toma, Sergio; Menegatti de Melo, Fernando [Instituto de Química, Universidade de São Paulo, São Paulo, SP (Brazil); Carvalho, Larissa Vieira C.; Magalhães, Alvicler; Sabadini, Edvaldo [Instituto de Química, Universidade Estadual de Campinas – UNICAMP, Campinas, SP (Brazil); Domingues dos Santos, Antônio [Instituto de Física, Universidade de São Paulo, São Paulo, SP (Brazil); Araki, Koiti [Instituto de Química, Universidade de São Paulo, São Paulo, SP (Brazil); Toma, Henrique E., E-mail: henetoma@iq.usp.br [Instituto de Química, Universidade de São Paulo, São Paulo, SP (Brazil)

    2016-01-01

    Iron(II) carboxymethylcellulose (CMC) has been successfully employed in the synthesis of hydrophylic magnetite nanoparticles stabilized with a biopolymer coating, aiming applications in NMR imaging. The new method encompasses a convenient one-step synthetic procedure, allowing a good size control and yielding particles of about 10 nm (core size). In addition to the biocompatibility, the nanoparticles have promoted a drastic reduction in the transverse relaxation time (T{sub 2}) of the water protons. The relaxivity rates have been investigated as a function of the nanoparticles concentration, showing a better performance in relation to the common NMR contrast agents available in the market. - Highlights: • Stable, hydrophylic magnetic nanoparticles have been obtained. • Direct use of iron(II) carboxymethylcellulose improves the synthesis. • The magnetic nanoparticles exhibit high spin–spin relaxivity. • The particles promote dark contrast by decreasing the T{sub 2} relaxation time.

  16. Hydrogen-Bonding Interactions Trigger a Spin-Flip in Iron(III) Porphyrin Complexes**

    Science.gov (United States)

    Sahoo, Dipankar; Quesne, Matthew G; de Visser, Sam P; Rath, Sankar Prasad

    2015-01-01

    A key step in cytochrome P450 catalysis includes the spin-state crossing from low spin to high spin upon substrate binding and subsequent reduction of the heme. Clearly, a weak perturbation in P450 enzymes triggers a spin-state crossing. However, the origin of the process whereby enzymes reorganize their active site through external perturbations, such as hydrogen bonding, is still poorly understood. We have thus studied the impact of hydrogen-bonding interactions on the electronic structure of a five-coordinate iron(III) octaethyltetraarylporphyrin chloride. The spin state of the metal was found to switch reversibly between high (S=5/2) and intermediate spin (S=3/2) with hydrogen bonding. Our study highlights the possible effects and importance of hydrogen-bonding interactions in heme proteins. This is the first example of a synthetic iron(III) complex that can reversibly change its spin state between a high and an intermediate state through weak external perturbations. PMID:26109743

  17. Experimental and Computational Evidence for the Mechanism of Intradiol Catechol Dioxygenation by Non- Heme Iron(III) Complexes

    NARCIS (Netherlands)

    Jastrzebski, Robin; Quesne, Matthew G.; Weckhuysen, Bert M.; de Visser, Sam P.; Bruijnincx, Pieter C. A.

    2014-01-01

    Catechol intradiol dioxygenation is a unique reaction catalyzed by iron-dependent enzymes and nonheme iron(III) complexes. The mechanism by which these systems activate dioxygen in this important metabolic process remains controversial. Using a combination of kinetic measurements and computational

  18. Separation of valence forms of chromium(III) and chromium(VI) by coprecipitation with iron(III) hydroxide

    International Nuclear Information System (INIS)

    Nazirmadov, B.; Khamidov, B.O.; Egorova, L.A.

    1989-01-01

    The sorption of 9.62·10 -5 M of Cr (III) and Cr (VI) with iron hydroxide in 1 M potassium nitrate and potassium chloride was investigated in relation to the pH of the medium. Experimental data on the sorption of chromium(III) and chromium(VI) with iron(III) hydroxide made it possible to determine the region of practically complete concentration of Cr (III) and Cr (VI) (pH = 3-6.5). The results from spectrophotometric investigations, calculated data on the distribution of the hydroxocationic forms of chromium(III) and the anions of chromium(IV), and their sorption by iron-(III) hydroxide made it possible to characterize the sorbability of the cationic and anionic forms of chromium in various degrees of oxidation. On this basis a method was developed for the separation of chromium(III) and chromium(VI) by coprecipitation on iron(III) hydroxide and their separation from the iron(III) hydroxide support

  19. Lithium ion intercalation into thin film anatase

    International Nuclear Information System (INIS)

    Kundrata, I.; Froehlich, K.; Ballo, P.

    2015-01-01

    The aim of this work is to find the optimal parameters for thin film TiO 2 anatase grown by Atomic layer deposition (ALD) for use as electrode in lithium ion batteries. Two parameters, the optimal film thickness and growth conditions are aimed for. Optimal film thickness for achieving optimum between capacity gained from volume and capacity gained by changing of the intercalation constant and optimal growth conditions for film conformity on structured substrates with high aspect ratio. Here we presents first results from this ongoing research and discuss future outlooks. (authors)

  20. Effect of Phosphorylation and Copper(II or Iron(II Ions Enrichment on Some Physicochemical Properties of Spelt Starch

    Directory of Open Access Journals (Sweden)

    Jacek Rożnowski

    Full Text Available ABSTRACT: This paper provides an assessment of the effect of saturation of spelt starch and monostarch phosphate with copper or iron ions on selected physicochemical properties of the resulting modified starches. Native and modified spelt starch samples were analyzed for selected mineral element content using Atomic Absorption Spectroscopy (AAS. Thermodynamic properties were measured using DSC, and pasting properties by RVA. Flow curves of 5% pastes were plotted and described using the Herschel-Bulkley model. The structure recovery ratio was measured. AAS analysis established the presence of iron(II and copper(II ions in the samples of modified starches and that potassium and magnesium ions had leached from them. In comparison to unfortified samples, enriching native starch with copper(II ions decreases value of all temperatures of phase transformation about 1.3-2.7 °C, but in case of monostarch phosphates bigger changes (2.8-3.7 °C were observed. Fortified native spelt starch with copper(II ions caused increasing the final viscosity of paste from 362 to 429 mPa·s. However, presence iron(II ions in samples caused reduced its final viscosity by 170 (spelt starch and 103 mPa·s (monostarch phosphate. Furthermore, enriching monostarch phosphate contributed to reduce degree of structure recovery of pastes from 70.9% to 66.6% in case of copper(II ions and to 59.9% in case of iron(II ions.

  1. Mechanism of Si intercalation in defective graphene on SiC

    KAUST Repository

    Kaloni, Thaneshwor P.; Cheng, Yingchun; Schwingenschlö gl, Udo; Upadhyay Kahaly, M.

    2012-01-01

    Previously reported experimental findings on Si-intercalated graphene on SiC(0001) seem to indicate the possibility of an intercalation process based on the migration of the intercalant through atomic defects in the graphene sheet. We employ density

  2. Hybrid n-Alkylamine Intercalated Layered Titanates for Solid Lubrication

    NARCIS (Netherlands)

    Gonzalez Rodriguez, P.; Yuan, H.; van den Nieuwenhuijzen, Karin Jacqueline Huberta; Lette, W.; Schipper, Dirk J.; ten Elshof, Johan E.

    2016-01-01

    The intercalation of different primary n-alkylamines in the structure of a layered titanate of the lepidocrocite type (H1.07Ti1.73O4) for application in high-temperature solid lubrication is reported. The intercalation process of the amines was explored by means of in situ small-angle X-ray

  3. Silica intercalated crystalline zirconium phosphate-type materials

    NARCIS (Netherlands)

    1988-01-01

    The present invention relates to intercalated crystalline zirconium phosphate-types compositions wherein the interlayers of said composition have been intercalated with three-dimensional silicon oxide pillars whereby the pillars comprise at least two silicon atom layers parallel to the clay

  4. Charge carrier density in Li-intercalated graphene

    KAUST Repository

    Kaloni, Thaneshwor P.; Cheng, Yingchun; Kahaly, M. Upadhyay; Schwingenschlö gl, Udo

    2012-01-01

    The electronic structures of bulk C 6Li, Li-intercalated free-standing bilayer graphene, and Li-intercalated bilayer and trilayer graphene on SiC(0 0 0 1) are studied using density functional theory. Our estimate of Young's modulus suggests that Li

  5. On lunisolar calendars and intercalation schemes in Southeast Asia

    Science.gov (United States)

    Gislén, Lars

    2018-04-01

    This is a survey of different calendar intercalation schemes, mainly in Southeast Asia. The Thai and Burmese Calendars, superficially very similar, are shown to have quite different and interesting intercalation schemes. We also investigate similarities between the original Burmese Calendar and the Romakasiddhânta from India.

  6. Polysulfide intercalated layered double hydroxides for metal capture applications

    Energy Technology Data Exchange (ETDEWEB)

    Kanatzidis, Mercouri G.; Ma, Shulan

    2017-04-04

    Polysulfide intercalated layered double hydroxides and methods for their use in vapor and liquid-phase metal capture applications are provided. The layered double hydroxides comprise a plurality of positively charged host layers of mixed metal hydroxides separated by interlayer spaces. Polysulfide anions are intercalated in the interlayer spaces.

  7. PYRENE INTERCALATING NUCLEIC ACIDS WITH A CARBON LINKER

    DEFF Research Database (Denmark)

    Østergaard, Michael E.; Wamberg, Michael Chr.; Pedersen, Erik Bjerregaard

    2011-01-01

    geminally attached. Fluorescence studies of this intercalating nucleic acid with the pyrene moieties inserted as a bulge showed formation of an excimer band. When a mismatch was introduced at the site of the intercalator, an excimer band was formed for the destabilized duplexes whereas an exciplex band...

  8. Quasi-freestanding graphene on Ni(111) by Cs intercalation

    KAUST Repository

    Alattas, Maha Hassan Mohssen

    2016-05-26

    A possible approach to achieve quasi-freestanding graphene on a substrate for technological purpose is the intercalation of alkali metal atoms. Cs intercalation between graphene and Ni(111) therefore is investigated using density functional theory, incorporating van der Waals corrections. It is known that direct contact between graphene and Ni(111) perturbs the Dirac states. We find that Cs intercalation restores the linear dispersion characteristic of Dirac fermions, which agrees with experiments, but the Dirac cone is shifted to lower energy, i.e., the graphene sheet is n-doped. Cs intercalation therefore decouples the graphene sheet from the substrate except for a charge transfer. On the other hand, the spin polarization of Ni(111) does not extend through the intercalated atoms to the graphene sheet, for which we find virtually spin-degeneracy.

  9. K-intercalated carbon systems: Effects of dimensionality and substrate

    KAUST Repository

    Kaloni, Thaneshwor P.

    2012-06-01

    Density functional theory is employed to investigate the electronic properties of K-intercalated carbon systems. Young\\'s modulus indicates that the intercalation increases the intrinsic stiffness. For K-intercalated bilayer graphene on SiC(0001) the Dirac cone is maintained, whereas a trilayer configuration exhibits a small splitting at the Dirac point. Interestingly, in contrast to many other intercalated carbon systems, the presence of the SiC(0001) substrate does not suppress but rather enhances the charge carrier density. Reasonably high values are found for all systems, the highest carrier density for the bilayer. The band structure and electron-phonon coupling of free-standing K-intercalated bilayer graphene points to a high probability for superconductivity in this system. © 2012 Europhysics Letters Association.

  10. Quasi-freestanding graphene on Ni(111) by Cs intercalation

    KAUST Repository

    Alattas, Maha Hassan Mohssen

    2017-01-08

    It is of technological interest to achieve quasi-freestanding graphene on a substrate. A possible approach is the intercalation of alkali metal atoms. Cs intercalation between graphene and Ni(111) is investigated using density functional theory, incorporating van der Waals corrections. It is known that direct contact between graphene and Ni(111) perturbs the Dirac states. Cs intercalation restores the linear dispersion characteristic of Dirac fermions, which is in agreement with experiments1, but the Dirac cone is shifted to lower energy, i.e., the graphene sheet is n-doped. Cs intercalation therefore effectively decouples the graphene sheet from the substrate except for a charge transfer. On the other hand, the spin polarization of Ni(111) does not extend through the intercalated atoms to the graphene sheet, for which we find virtually spin-degeneracy.

  11. Intercalation studies of zinc hydroxide chloride: Ammonia and amino acids

    Science.gov (United States)

    Arízaga, Gregorio Guadalupe Carbajal

    2012-01-01

    Zinc hydroxide chloride (ZHC) is a layered hydroxide salt with formula Zn5(OH)8Cl2·2H2O. It was tested as intercalation matrix for the first time and results were compared with intercalation products of the well-known zinc hydroxide nitrate and a Zn/Al layered double hydroxide. Ammonia was intercalated into ZHC, while no significant intercalation occurred in ZHN. Aspartic acid intercalation was only achieved by co-precipitation at pH=10 with ZHC and pH=8 with zinc hydroxide nitrate. Higher pH resistance in ZHC favored total deprotonation of both carboxylic groups of the Asp molecule. ZHC conferred more thermal protection against Asp combustion presenting exothermic peaks even at 452 °C while the exothermic event in ZHN was 366 °C and in the LDH at 276 °C.

  12. High-Temperature Wide Thermal Hysteresis of an Iron(II Dinuclear Double Helicate

    Directory of Open Access Journals (Sweden)

    Shiori Hora

    2017-07-01

    Full Text Available Two new dinuclear iron(II complexes (1·PF6 and 1·AsF6 of the general formula [FeII2(L2C32](X4·nH2O·mMeCN (X = PF6, n = m = 1.5 for 1·PF6 and X = AsF6, n = 3, m = 1 for 1·AsF6 have been prepared and structurally characterized, where L2C3 is a bis-1,2,3-triazolimine type Schiff-base ligand, 1,1′-[propane-1,3-diylbis(1H-1,2,3-triazole-1,4-diyl]bis{N-[2-(pyridin-2-ylethyl]methanimine}. Single crystal X-ray structure analyses revealed that 1·PF6 and 1·AsF6 are isostructural. The complex-cation [FeII2(L2C32]4+ of both has the same dinuclear double helicate architecture, in which each iron(II center has an N6 octahedral coordination environment. Neighboring helicates are connected by intermolecular π–π interactions to give a chiral one-dimensional (1D structure, and cationic 1D chains with the opposite chirality exist in the crystal lattice to give a heterochiral crystal. Magnetic and differential scanning calorimetry (DSC studies were performed only for 1·AsF6, since the thermal stability in a high-temperature spin crossover (SCO region of 1·PF6 is poorer than that of 1·AsF6. 1·AsF6 shows an unsymmetrical hysteretic SCO between the low-spin–low-spin (LS–LS and high-spin–high-spin (HS–HS states at above room temperature. The critical temperatures of warming (Tc↑ and cooling (Tc↓ modes in the abrupt spin transition area are 485 and 401 K, respectively, indicating the occurrence of 84 K-wide thermal hysteresis in the first thermal cycle.

  13. Spectrophotometric Determination of Iron(II after Solid Phase Extraction of Its 2,2′ Bipyridine Complex on Silica Gel-Polyethylene Glycol

    Directory of Open Access Journals (Sweden)

    Nahid Pourreza

    2013-01-01

    Full Text Available A new solid phase extraction procedure was developed for preconcentration of iron(II using silica gel-polyethylene glycol (silica-PEG as an adsorbent. The method is based on retention of iron(II as 2,2′ bipyridine complex on silica-PEG. The retained complex is eluted by 1.0 mol L−1 of sulfuric acid-acetone mixture (1:2 and its absorbance is measured at 518 nm, spectrophotometrically. The effects of different parameters such as pH, concentration of the reagent, eluting reagent, sample volume, amount of adsorbent, and interfering ions were investigated. The calibration graph was linear in the range of 1–60 ng mL−1 of iron(II. The limit of detection based on 3Sb was 0.57 ng mL−1 and relative standard deviations (R.S.D for ten replicate measurements of 12 and 42 ng mL−1 of iron(II were 2.4 and 1.7%, respectively. The method was applied to the determination of of iron(II in water, multivitamin tablet, and spinach samples.

  14. High pressure measurement of the uniaxial stress of host layers on intercalants and staging transformation of intercalation compounds

    CERN Document Server

    Park, T R; Kim, H; Min, P

    2002-01-01

    A layered double-hydroxide intercalation compound was synthesized to measure the uniaxial stress the host layers exert on the intercalants. To measure the uniaxial stress, we employed the photoluminescence (PL) from the intercalated species, the Sm ion complex, as it is sensitive to the deformation of the intercalants. Of the many PL peaks the Sm ion complex produces, the one that is independent of the counter-cation environment was chosen for the measurement since the Sm ion complexes are placed under a different electrostatic environment after intercalation. The peak position of the PL was redshifted linearly with increasing hydrostatic pressure on the intercalated sample. Using this pressure-induced redshifting rate and the PL difference at ambient pressure between the pre-intercalation and the intercalated ions, we found that, in the absence of external pressure, the uniaxial stress exerted on the samarium ion complexes by the host layers was about 13.9 GPa at room temperature. Time-resolved PL data also ...

  15. Novel spin transition between S = 5/2 and S = 3/2 in highly saddled iron(III) porphyrin complexes at extremely low temperatures.

    Science.gov (United States)

    Ohgo, Yoshiki; Chiba, Yuya; Hashizume, Daisuke; Uekusa, Hidehiro; Ozeki, Tomoji; Nakamura, Mikio

    2006-05-14

    A novel spin transition between S = 5/2 and S = 3/2 has been observed for the first time in five-coordinate, highly saddled iron(III) porphyrinates by EPR and SQUID measurements at extremely low temperatures.

  16. Complexation equilibria and spectrophotometric determination of iron(III) with 1-amino-4-hydroxyanthraquinone.

    Science.gov (United States)

    Abu-Bakr, M S; Sedaira, H; Hashem, E Y

    1994-10-01

    The complex equilibria of iron(III) with 1-amino-4-hydroxyanthraquinone (AMHA) were studied spectrophotometrically in 40% (v/v) ethanol and an ionic strength of 0.1M (NaClO(4)). The complexation reactions were demonstrated and characterized using graphical logarithmic analysis of the absorbance-pH graphs. A simple, rapid, selective and sensitive method for the spectrophotometric determination of trace amounts of Fe(III) is developed based on the formation of Fe(AMHA) complex at pH 2.5 (lambda(max) = 640 nm, epsilon approximately = 2.1 x 10(4) L. mol(-1) . cm(-1)) in the presence of a large number of foreign ions. Interferences caused by palladium(II) was masked by the addition of cyanide ions. The method has been applied to the determination of iron in some synthetic samples and polymetallic iron ores.

  17. Aquachloridobis[5-(2-pyridyl-1H-tetrazolato-κN1]iron(III

    Directory of Open Access Journals (Sweden)

    Bo Wang

    2009-08-01

    Full Text Available The title compound, [Fe(C6H4N52Cl(H2O], was synthesized by hydrothermal reaction of FeCl3 with 2-(1H-tetrazol-5-ylpyridine. The iron(III metal centre exhibits a distorted octahedral coordination geometry provided by four N atoms from two bidentate organic ligands, one water O atom and one chloride anion. The pyridine and tetrazole rings are nearly coplanar [dihedral angles = 4.32 (15 and 5.04 (14°]. In the crystal structure, intermolecular O—H...N hydrogen bonds link the complex molecules into a two-dimensional network parallel to (100.

  18. N-butylamine functionalized graphene oxide for detection of iron(III) by photoluminescence quenching.

    Science.gov (United States)

    Gholami, Javad; Manteghian, Mehrdad; Badiei, Alireza; Ueda, Hiroshi; Javanbakht, Mehran

    2016-02-01

    An N-butylamine functionalized graphene oxide nanolayer was synthesized and characterized by ultraviolet (UV)-visible spectrometry, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. Detection of iron(III) based on photoluminescence spectroscopy was investigated. The N-butylamine functionalized graphene oxide was shown to specifically interact with iron (III), compared with other cationic trace elements including potassium (I), sodium (I), calcium (II), chromium (III), zinc (II), cobalt (II), copper (II), magnesium (II), manganese (II), and molybdenum (VI). The quenching effect of iron (III) on the luminescence emission of N-butylamine functionalized graphene oxide layer was used to detect iron (III). The limit of detection (2.8 × 10(-6)  M) and limit of quantitation (2.9 × 10(-5)  M) were obtained under optimal conditions. Copyright © 2015 John Wiley & Sons, Ltd.

  19. Isolation of microorganisms involved in reduction of crystalline iron(III) oxides in natural environments.

    Science.gov (United States)

    Hori, Tomoyuki; Aoyagi, Tomo; Itoh, Hideomi; Narihiro, Takashi; Oikawa, Azusa; Suzuki, Kiyofumi; Ogata, Atsushi; Friedrich, Michael W; Conrad, Ralf; Kamagata, Yoichi

    2015-01-01

    Reduction of crystalline Fe(III) oxides is one of the most important electron sinks for organic compound oxidation in natural environments. Yet the limited number of isolates makes it difficult to understand the physiology and ecological impact of the microorganisms involved. Here, two-stage cultivation was implemented to selectively enrich and isolate crystalline iron(III) oxide reducing microorganisms in soils and sediments. Firstly, iron reducers were enriched and other untargeted eutrophs were depleted by 2-years successive culture on a crystalline ferric iron oxide (i.e., goethite, lepidocrocite, hematite, or magnetite) as electron acceptor. Fifty-eight out of 136 incubation conditions allowed the continued existence of microorganisms as confirmed by PCR amplification. High-throughput Illumina sequencing and clone library analysis based on 16S rRNA genes revealed that the enrichment cultures on each of the ferric iron oxides contained bacteria belonging to the Deltaproteobacteria (mainly Geobacteraceae), followed by Firmicutes and Chloroflexi, which also comprised most of the operational taxonomic units (OTUs) identified. Venn diagrams indicated that the core OTUs enriched with all of the iron oxides were dominant in the Geobacteraceae while each type of iron oxides supplemented selectively enriched specific OTUs in the other phylogenetic groups. Secondly, 38 enrichment cultures including novel microorganisms were transferred to soluble-iron(III) containing media in order to stimulate the proliferation of the enriched iron reducers. Through extinction dilution-culture and single colony isolation, six strains within the Deltaproteobacteria were finally obtained; five strains belonged to the genus Geobacter and one strain to Pelobacter. The 16S rRNA genes of these isolates were 94.8-98.1% identical in sequence to cultured relatives. All the isolates were able to grow on acetate and ferric iron but their physiological characteristics differed considerably in

  20. Reconstruction of Extracellular Respiratory Pathways for Iron(III Reduction in Shewanella oneidensis strain MR-1

    Directory of Open Access Journals (Sweden)

    Dan eCoursolle

    2012-02-01

    Full Text Available Shewanella oneidensis strain MR-1 is a facultative anaerobic bacterium capable of respiring a multitude of electron acceptors, many of which require the Mtr respiratory pathway. The core Mtr respiratory pathway includes a periplasmic c-type cytochrome (MtrA, an integral outer membrane β-barrel protein (MtrB and an outer membrane-anchored c-type cytochrome (MtrC. Together, these components facilitate transfer of electrons from the c-type cytochrome CymA in the cytoplasmic membrane to electron acceptors at and beyond the outer membrane. The genes encoding these core proteins have paralogs in the S. oneidensis genome (mtrB and mtrA each have four while mtrC has three and some of the paralogs of mtrC and mtrA are able to form functional Mtr complexes. We demonstrate that of the additional three mtrB paralogs found in the S. oneidensis genome, only MtrE can replace MtrB to form a functional respiratory pathway to soluble iron(III citrate. We also evaluate which mtrC / mtrA paralog pairs (a total of 12 combinations are able to form functional complexes with endogenous levels of mtrB paralog expression. Finally, we reconstruct all possible functional Mtr complexes and test them in a S. oneidensis mutant strain where all paralogs have been eliminated from the genome. We find that each combination tested with the exception of MtrA / MtrE / OmcA is able to reduce iron(III citrate at a level significantly above background. The results presented here have implications towards the evolution of anaerobic extracellular respiration in Shewanella and for future studies looking to increase the rates of substrate reduction for water treatment, bioremediation, or electricity production.

  1. Intercalation and controlled release properties of vitamin C intercalated layered double hydroxide

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Xiaorui, E-mail: gxr_1320@sina.com [College of Science, Hebei University of Engineering, Handan 056038 (China); School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189 (China); Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA (United Kingdom); Lei, Lixu [School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189 (China); O' Hare, Dermot [Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA (United Kingdom); Xie, Juan [College of Science, Hebei University of Engineering, Handan 056038 (China); Gao, Pengran [School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189 (China); Chang, Tao [College of Science, Hebei University of Engineering, Handan 056038 (China)

    2013-07-15

    Two drug-inorganic composites involving vitamin C (VC) intercalated in Mg–Al and Mg–Fe layered double hydroxides (LDHs) have been synthesized by the calcination–rehydration (reconstruction) method. Powder X-ray diffraction (XRD), Fourier transform infrared (FTIR), and UV–vis absorption spectroscopy indicate a successful intercalation of VC into the interlayer galleries of the LDH host. Studies of VC release from the LDHs in deionised water and in aqueous CO{sub 3}{sup 2−} solutions imply that Mg{sub 3}Al–VC LDH is a better controlled release system than Mg{sub 3}Fe–VC LDH. Analysis of the release profiles using a number of kinetic models suggests a solution-dependent release mechanism, and a diffusion-controlled deintercalation mechanism in deionised water, but an ion exchange process in CO{sub 3}{sup 2−} solution. - Graphical abstract: Vitamin C anions have been intercalated in the interlayer space of layered double hydroxide and released in CO{sub 3}{sup 2−} solution and deionised water. - Highlights: • Vitamin C intercalated Mg–Al and Mg–Fe layered double hydroxides were prepared. • Release property of vitamin C in aqueous CO{sub 3}{sup 2−} solution is better. • Avrami-Erofe’ev and first-order models provide better fit for release results. • Diffusion-controlled and ion exchange processes occur in deionised water. • An ion exchange process occurs in CO{sub 3}{sup 2−} solution.

  2. Synthesis, spectroscopy, and hydrogen/deuterium exchange in high-spin iron(II) hydride complexes.

    Science.gov (United States)

    Dugan, Thomas R; Bill, Eckhard; MacLeod, K Cory; Brennessel, William W; Holland, Patrick L

    2014-03-03

    Very few hydride complexes are known in which the metals have a high-spin electronic configuration. We describe the characterization of several high-spin iron(II) hydride/deuteride isotopologues and their exchange reactions with one another and with H2/D2. Though the hydride/deuteride signal is not observable in NMR spectra, the choice of isotope has an influence on the chemical shifts of distant protons in the dimers through the paramagnetic isotope effect on chemical shift. This provides the first way to monitor the exchange of H and D in the bridging positions of these hydride complexes. The rate of exchange depends on the size of the supporting ligand, and this is consistent with the idea that H2/D2 exchange into the hydrides occurs through the dimeric complexes rather than through a transient monomer. The understanding of H/D exchange mechanisms in these high-spin iron hydride complexes may be relevant to postulated nitrogenase mechanisms.

  3. Intercalation compounds involving inorganic layered structures

    Directory of Open Access Journals (Sweden)

    CONSTANTINO VERA R. L.

    2000-01-01

    Full Text Available Two-dimensional inorganic networks can shown intracrystalline reactivity, i.e., simple ions, large species as Keggin ions, organic species, coordination compounds or organometallics can be incorporated in the interlayer region. The host-guest interaction usually causes changes in their chemical, catalytic, electronic and optical properties. The isolation of materials with interesting properties and making use of soft chemistry routes have given rise the possibility of industrial and technological applications of these compounds. We have been using several synthetic approaches to intercalate porphyrins and phthalocyanines into inorganic materials: smectite clays, layered double hydroxides and layered niobates. The isolated materials have been characterized by elemental and thermal analysis, X-ray diffraction, surface area measurements, scanning electronic microscopy, electronic and resonance Raman spectroscopies and EPR. The degree of layer stacking and the charge density of the matrices as well their acid-base nature were considered in our studies on the interaction between the macrocycles and inorganic hosts.

  4. Renal intercalated cells and blood pressure regulation

    Directory of Open Access Journals (Sweden)

    Susan M. Wall

    2017-12-01

    Full Text Available Type B and non-A, non-B intercalated cells are found within the connecting tubule and the cortical collecting duct. Of these cell types, type B intercalated cells are known to mediate Cl⁻ absorption and HCO₃⁻ secretion largely through pendrin-dependent Cl⁻/HCO₃⁻ exchange. This exchange is stimulated by angiotensin II administration and is also stimulated in models of metabolic alkalosis, for instance after aldosterone or NaHCO₃ administration. In some rodent models, pendrin-mediated HCO₃⁻ secretion modulates acid-base balance. However, the role of pendrin in blood pressure regulation is likely of more physiological or clinical significance. Pendrin regulates blood pressure not only by mediating aldosterone-sensitive Cl⁻ absorption, but also by modulating the aldosterone response for epithelial Na⁺ channel (ENaC-mediated Na⁺ absorption. Pendrin regulates ENaC through changes in open channel of probability, channel surface density, and channels subunit total protein abundance. Thus, aldosterone stimulates ENaC activity through both direct and indirect effects, the latter occurring through its stimulation of pendrin expression and function. Therefore, pendrin contributes to the aldosterone pressor response. Pendrin may also modulate blood pressure in part through its action in the adrenal medulla, where it modulates the release of catecholamines, or through an indirect effect on vascular contractile force. This review describes how aldosterone and angiotensin II-induced signaling regulate pendrin and the contributory role of pendrin in distal nephron function and blood pressure.

  5. Design and synthesis of a tetradentate '3-amine-1-carboxylate' ligand to mimic the metal binding environment at the non-heme iron(II) oxidase active site.

    Science.gov (United States)

    Dungan, Victoria J; Ortin, Yannick; Mueller-Bunz, Helge; Rutledge, Peter J

    2010-04-07

    Non-heme iron(II) oxidases (NHIOs) catalyse a diverse array of oxidative chemistry in Nature. As part of ongoing efforts to realize biomimetic, iron-mediated C-H activation, we report the synthesis of a new 'three-amine-one-carboxylate' ligand designed to complex with iron(II) and mimic the NHIO active site. The tetradentate ligand has been prepared as a single enantiomer in nine synthetic steps from N-Cbz-L-alanine, pyridine-2,6-dimethanol and diphenylamine, using Seebach oxazolidinone chemistry to control the stereochemistry. X-Ray crystal structures are reported for two important intermediates, along with variable temperature NMR experiments to probe the hindered interconversion of conformational isomers of several key intermediates, 2,6-disubstituted pyridine derivatives. The target ligand and an N-Cbz-protected precursor were each then complexed with iron(II) and tested for their ability to promote alkene dihydroxylation, using hydrogen peroxide as the oxidant.

  6. Optimization of colorimetric DET technique for the in situ, two-dimensional measurement of iron(II) distributions in sediment porewaters

    DEFF Research Database (Denmark)

    Bennett, William W.; Teasdale, Peter R.; Welsh, David T.

    2012-01-01

    The recently developed colorimetric diffusive equilibration in thin films (DET) technique for the in situ, high-resolution measurement of iron(II) in marine sediments is optimized to allow measurement of the higher iron concentrations typical of freshwater sediment porewaters. Computer imaging...... the sensitivity of the assay as required; by processing the image with different color channel filters, the sensitivity of the assay can be optimized for lower concentrations (up to 100 μmol L -1) or higher concentrations (up to 2000 μmol L -1) of iron(II), depending on the specific site characteristics......(II) in sediment porewaters. The detection limit of the optimized technique was 4.1 ± 0.3 μmol L -1 iron(II) and relative standard deviations were less than 6%....

  7. Intercalation studies of zinc hydroxide chloride: Ammonia and amino acids

    International Nuclear Information System (INIS)

    Arízaga, Gregorio Guadalupe Carbajal

    2012-01-01

    Zinc hydroxide chloride (ZHC) is a layered hydroxide salt with formula Zn 5 (OH) 8 Cl 2 ·2H 2 O. It was tested as intercalation matrix for the first time and results were compared with intercalation products of the well-known zinc hydroxide nitrate and a Zn/Al layered double hydroxide. Ammonia was intercalated into ZHC, while no significant intercalation occurred in ZHN. Aspartic acid intercalation was only achieved by co-precipitation at pH=10 with ZHC and pH=8 with zinc hydroxide nitrate. Higher pH resistance in ZHC favored total deprotonation of both carboxylic groups of the Asp molecule. ZHC conferred more thermal protection against Asp combustion presenting exothermic peaks even at 452 °C while the exothermic event in ZHN was 366 °C and in the LDH at 276 °C. - Graphical abstract: The zinc hydroxide chloride (ZHC) with formula Zn 5 (OH) 8 Cl 2 ·2H 2 O was tested as intercalation matrix. In comparison with the well-known zinc hydroxide nitrate (ZHN) and layered double hydroxides (LDH), ZHC was the best matrix for thermal protection of Asp combustion, presenting exothermic peaks even at 452 °C, while the highest exothermic event in ZHN was at 366 °C, and in the LDH it was at 276 °C. Highlights: ► Zinc hydroxide chloride (ZHC) was tested as intercalation matrix for the first time. ► ZHC has higher chemical and thermal stability than zinc hydroxide nitrate and LDH. ► NH 3 molecules can be intercalated into ZHC. ► The amino group of amino acids limits the intercalation by ion-exchange.

  8. Prediction of superconductivity in Li-intercalated bilayer phosphorene

    International Nuclear Information System (INIS)

    Huang, G. Q.; Xing, Z. W.; Xing, D. Y.

    2015-01-01

    It is shown that bilayer phosphorene can be transformed from a direct-gap semiconductor to a BCS superconductor by intercalating Li atoms. For the Li-intercalated bilayer phosphorene, we find that the electron occupation of Li-derived band is small and superconductivity is intrinsic. With increasing the intercalation of Li atoms, both increased metallicity and strong electron-phonon coupling are favorable for the enhancement of superconductivity. The obtained electron-phonon coupling λ can be larger than 1 and the superconducting temperature T c can be increased up to 16.5 K, suggesting that phosphorene may be a good candidate for a nanoscale superconductor

  9. Prediction of superconductivity in Li-intercalated bilayer phosphorene

    Energy Technology Data Exchange (ETDEWEB)

    Huang, G. Q. [Department of Physics, Nanjing Normal University, Nanjing 210023 (China); National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Xing, Z. W., E-mail: zwxing@nju.edu.cn [National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Xing, D. Y. [National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Collaborative Innovation Center of Advanced Microstructures and Department of Physics, Nanjing University, Nanjing 210093 (China)

    2015-03-16

    It is shown that bilayer phosphorene can be transformed from a direct-gap semiconductor to a BCS superconductor by intercalating Li atoms. For the Li-intercalated bilayer phosphorene, we find that the electron occupation of Li-derived band is small and superconductivity is intrinsic. With increasing the intercalation of Li atoms, both increased metallicity and strong electron-phonon coupling are favorable for the enhancement of superconductivity. The obtained electron-phonon coupling λ can be larger than 1 and the superconducting temperature T{sub c} can be increased up to 16.5 K, suggesting that phosphorene may be a good candidate for a nanoscale superconductor.

  10. Strain Lattice Imprinting in Graphene by C60 Intercalation at the Graphene/Cu Interface

    NARCIS (Netherlands)

    Monazami, Ehsan; Bignardi, Luca; Rudolf, Petra; Reinke, Petra

    2015-01-01

    Intercalation of C60 molecules at the graphene-substrate interface by annealing leads to amorphous and crystalline intercalated structures. A comparison of topography and electronic structure with wrinkles and moiré patterns confirms intercalation. The intercalated molecules imprint a local

  11. Determination of silver in fresh water by atomic absorption spectrometry following flotation preconcentration by iron(III) collectors

    Energy Technology Data Exchange (ETDEWEB)

    Cundeva, K.; Stafilov, T. [Institute of Chemistry, Faculty of Science, St. Cyril and Methodius University, Skopje (Yugoslavia)

    1997-08-01

    Colloid precipitate flotation of silver from fresh water is applied for preconcentration and separation. Optimal conditions using hydrated iron(III) oxide and iron(III) tetramethylenedithiocarbamate as collectors were investigated. Various factors affecting the silver recovery, including collector mass, nature of the supporting electrolyte, pH of the working medium, electrokinetic potential of the collector particle surfaces, type of surfactant, induction time etc., were checked. Within the optimal pH range (5.5-6.5) silver was separated quantitatively (94.9- 100.0%) with 30 mg Fe(III) as collector. The content of silver was determined by electrothermal atomic absorption spectrometry and compared to that from inductively coupled plasma-atomic emission spectrometry. The detection limit of silver by the method described is 0.01 {mu}g/L. (orig.) With 2 figs., 3 tabs.

  12. Iron(iii) bis(pyrazol-1-yl)acetate based decanuclear metallacycles: synthesis, structure, magnetic properties and DFT calculations.

    Science.gov (United States)

    Gajewska, Małgorzata J; Bieńko, Alina; Herchel, Radovan; Haukka, Matti; Jerzykiewicz, Maria; Ożarowski, Andrzej; Drabent, Krzysztof; Hung, Chen-Hsiung

    2016-09-27

    The synthesis, structural aspects, magnetic interpretation and theoretical rationalizations for a new member of the ferric wheel family, a decanuclear iron(iii) complex with the formula [Fe 10 (bdtbpza) 10 (μ 2 -OCH 3 ) 20 ] (1), featuring the N,N,O tridentate bis(3,5-di-tert-butylpyrazol-1-yl)acetate ligand, are reported. The influence of the steric effect on both the core geometry and coordination mode is observed. Temperature dependent (2.0-300 K range) magnetic susceptibility studies carried out on complexes 1 established unequivocally antiferromagnetic (AF) interactions between high-spin iron(iii) centers (S = 5/2), leading to a ground state S = 0. The mechanism of AF intramolecular coupling was proved using a broken-symmetry approach within the density functional method at the B3LYP/def2-TZVP(-f)/def2-SVP level of theory.

  13. Extracellular polymeric substances mediate bioleaching/biocorrosion via interfacial processes involving iron(III) ions and acidophilic bacteria.

    Science.gov (United States)

    Sand, Wolfgang; Gehrke, Tilman

    2006-01-01

    Extracellular polymeric substances seem to play a pivotal role in biocorrosion of metals and bioleaching, biocorrosion of metal sulfides for the winning of precious metals as well as acid rock drainage. For better control of both processes, the structure and function of extracellular polymeric substances of corrosion-causing or leaching bacteria are of crucial importance. Our research focused on the extremophilic bacteria Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans, because of the "simplicity" and knowledge about the interactions of these bacteria with their substrate/substratum and their environment. For this purpose, the composition of the corresponding extracellular polymeric substances and their functions were analyzed. The extracellular polymeric substances of both species consist mainly of neutral sugars and lipids. The functions of the exopolymers seem to be: (i) to mediate attachment to a (metal) sulfide surface, and (ii) to concentrate iron(III) ions by complexation through uronic acids or other residues at the mineral surface, thus, allowing an oxidative attack on the sulfide. Consequently, dissolution of the metal sulfide is enhanced, which may result in an acceleration of 20- to 100-fold of the bioleaching process over chemical leaching. Experiments were performed to elucidate the importance of the iron(III) ions complexed by extracellular polymeric substances for strain-specific differences in oxidative activity for pyrite. Strains of A. ferrooxidans with a high amount of iron(III) ions in their extracellular polymeric substances possess greater oxidation activity than those with fewer iron(III) ions. These data provide insight into the function of and consequently the advantages that extracellular polymeric substances provide to bacteria. The role of extracellular polymeric substances for attachment under the conditions of a space station and resulting effects like biofouling, biocorrosion, malodorous gases, etc. will be discussed.

  14. Iodometric determination of peroxydiphosphate in the presence of copper(II) or iron(II) as catalyst.

    Science.gov (United States)

    Kapoor, S; Sharma, P D; Gupta, Y K

    1975-09-01

    Peroxydiphosphate can be determined iodometrically in the presence of a large excess of potassium iodide with copper(II) or iron(II) as catalyst through the operation of the Cu(II)/Cu(I) or Fe(II)/Fe(III) cycle. The method is applicable in HClO(4), H(2)SO(4), HCl and CH(3)COOH acid media in the range 0.1-1.0M studied. Nickel, manganese(II), cobalt(II), silver, chloride and phosphate are without effect.

  15. Syntheses, structure and intercalation properties of low-dimensional ...

    Indian Academy of Sciences (India)

    Unknown

    Successful intercalation reactions of compounds 1 and 2 with primary n- alkyl amines have ... and hexavalent metal phenylphosphonates12–17 with ..... Similarly potassium. (3) and ..... ponds to loss of one water molecule, whereas the stage at ...

  16. Lithium isotope effect accompanying electrochemical intercalation of lithium into graphite

    CERN Document Server

    Yanase, S; Oi, T

    2003-01-01

    Lithium has been electrochemically intercalated from a 1:2 (v/v) mixed solution of ethylene carbonate (EC) and methylethyl carbonate (MEC) containing 1 M LiClO sub 4 into graphite, and the lithium isotope fractionation accompanying the intercalation was observed. The lighter isotope was preferentially fractionated into graphite. The single-stage lithium isotope separation factor ranged from 1.007 to 1.025 at 25 C and depended little on the mole ratio of lithium to carbon of the lithium-graphite intercalation compounds (Li-GIC) formed. The separation factor increased with the relative content of lithium. This dependence seems consistent with the existence of an equilibrium isotope effect between the solvated lithium ion in the EC/MEC electrolyte solution and the lithium in graphite, and with the formation of a solid electrolyte interfaces on graphite at the early stage of intercalation. (orig.)

  17. Method for intercalating alkali metal ions into carbon electrodes

    Science.gov (United States)

    Doeff, Marca M.; Ma, Yanping; Visco, Steven J.; DeJonghe, Lutgard

    1995-01-01

    A low cost, relatively flexible, carbon electrode for use in a secondary battery is described. A method is provided for producing same, including intercalating alkali metal salts such as sodium and lithium into carbon.

  18. Refining the molecular organization of the cardiac intercalated disc

    NARCIS (Netherlands)

    Vermij, Sarah H.; Abriel, Hugues; van Veen, Toon A.B.

    2017-01-01

    This review presents an extensively integrated model of the cardiac intercalated disc (ID), a highly orchestrated structure that connects adjacent cardiomyocytes. Classically, three main structures are distinguished: gap junctions (GJs) metabolically and electrically connect cytoplasm of adjacent

  19. Synthesis and Characterization of Highly Intercalated Graphite Bisulfate

    OpenAIRE

    Salvatore, Marcella; Carotenuto, Gianfranco; De Nicola, Sergio; Camerlingo, Carlo; Ambrogi, Veronica; Carfagna, Cosimo

    2017-01-01

    Different chemical formulations for the synthesis of highly intercalated graphite bisulfate have been tested. In particular, nitric acid, potassium nitrate, potassium dichromate, potassium permanganate, sodium periodate, sodium chlorate, and hydrogen peroxide have been used in this synthesis scheme as the auxiliary reagent (oxidizing agent). In order to evaluate the presence of delamination, and pre-expansion phenomena, and the achieved intercalation degree in the prepared samples, the obtain...

  20. Synthesis of graphene nanoplatelets from peroxosulfate graphite intercalation compounds

    OpenAIRE

    MELEZHYK A.V.; TKACHEV A.G.

    2014-01-01

    Ultrasonic exfoliation of expanded graphite compound obtained by cold expansion of graphite intercalated with peroxodisulfuric acid was shown to allow the creation of graphene nanoplatelets with thickness of about 5-10 nm. The resulting graphene material contained surface oxide groups. The expanded graphite intercalation compound was exfoliated by ultrasound much easier than thermally expanded graphite. A mechanism for the cleavage of graphite to graphene nanoplatelets is proposed. It include...

  1. Predicting critical temperatures of iron(II) spin crossover materials: Density functional theory plus U approach

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yachao, E-mail: yczhang@nano.gznc.edu.cn [Guizhou Provincial Key Laboratory of Computational Nano-Material Science, Guizhou Normal College, Guiyang 550018, Guizhou (China)

    2014-12-07

    A first-principles study of critical temperatures (T{sub c}) of spin crossover (SCO) materials requires accurate description of the strongly correlated 3d electrons as well as much computational effort. This task is still a challenge for the widely used local density or generalized gradient approximations (LDA/GGA) and hybrid functionals. One remedy, termed density functional theory plus U (DFT+U) approach, introduces a Hubbard U term to deal with the localized electrons at marginal computational cost, while treats the delocalized electrons with LDA/GGA. Here, we employ the DFT+U approach to investigate the T{sub c} of a pair of iron(II) SCO molecular crystals (α and β phase), where identical constituent molecules are packed in different ways. We first calculate the adiabatic high spin-low spin energy splitting ΔE{sub HL} and molecular vibrational frequencies in both spin states, then obtain the temperature dependent enthalpy and entropy changes (ΔH and ΔS), and finally extract T{sub c} by exploiting the ΔH/T − T and ΔS − T relationships. The results are in agreement with experiment. Analysis of geometries and electronic structures shows that the local ligand field in the α phase is slightly weakened by the H-bondings involving the ligand atoms and the specific crystal packing style. We find that this effect is largely responsible for the difference in T{sub c} of the two phases. This study shows the applicability of the DFT+U approach for predicting T{sub c} of SCO materials, and provides a clear insight into the subtle influence of the crystal packing effects on SCO behavior.

  2. Synthesis and Characterization of Highly Intercalated Graphite Bisulfate

    Science.gov (United States)

    Salvatore, Marcella; Carotenuto, Gianfranco; De Nicola, Sergio; Camerlingo, Carlo; Ambrogi, Veronica; Carfagna, Cosimo

    2017-03-01

    Different chemical formulations for the synthesis of highly intercalated graphite bisulfate have been tested. In particular, nitric acid, potassium nitrate, potassium dichromate, potassium permanganate, sodium periodate, sodium chlorate, and hydrogen peroxide have been used in this synthesis scheme as the auxiliary reagent (oxidizing agent). In order to evaluate the presence of delamination, and pre-expansion phenomena, and the achieved intercalation degree in the prepared samples, the obtained graphite intercalation compounds have been characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray powder diffraction (XRD), infrared spectroscopy (FT-IR), micro-Raman spectroscopy ( μ-RS), and thermal analysis (TGA). Delamination and pre-expansion phenomena were observed only for nitric acid, sodium chlorate, and hydrogen peroxide, while the presence of strong oxidizers (KMnO4, K2Cr2O7) led to stable graphite intercalation compounds. The largest content of intercalated bisulfate is achieved in the intercalated compounds obtained from NaIO4 and NaClO3.

  3. Discriminating Intercalative Effects of Threading Intercalator Nogalamycin, from Classical Intercalator Daunomycin, Using Single Molecule Atomic Force Spectroscopy.

    Directory of Open Access Journals (Sweden)

    T Banerjee

    Full Text Available DNA threading intercalators are a unique class of intercalating agents, albeit little biophysical information is available on their intercalative actions. Herein, the intercalative effects of nogalamycin, which is a naturally-occurring DNA threading intercalator, have been investigated by high-resolution atomic force microscopy (AFM and spectroscopy (AFS. The results have been compared with those of the well-known chemotherapeutic drug daunomycin, which is a non-threading classical intercalator bearing structural similarity to nogalamycin. A comparative AFM assessment revealed a greater increase in DNA contour length over the entire incubation period of 48 h for nogalamycin treatment, whereas the contour length increase manifested faster in case of daunomycin. The elastic response of single DNA molecules to an externally applied force was investigated by the single molecule AFS approach. Characteristic mechanical fingerprints in the overstretching behaviour clearly distinguished the nogalamycin/daunomycin-treated dsDNA from untreated dsDNA-the former appearing less elastic than the latter, and the nogalamycin-treated DNA distinguished from the daunomycin-treated DNA-the classically intercalated dsDNA appearing the least elastic. A single molecule AFS-based discrimination of threading intercalation from the classical type is being reported for the first time.

  4. Discriminating Intercalative Effects of Threading Intercalator Nogalamycin, from Classical Intercalator Daunomycin, Using Single Molecule Atomic Force Spectroscopy.

    Science.gov (United States)

    Banerjee, T; Banerjee, S; Sett, S; Ghosh, S; Rakshit, T; Mukhopadhyay, R

    2016-01-01

    DNA threading intercalators are a unique class of intercalating agents, albeit little biophysical information is available on their intercalative actions. Herein, the intercalative effects of nogalamycin, which is a naturally-occurring DNA threading intercalator, have been investigated by high-resolution atomic force microscopy (AFM) and spectroscopy (AFS). The results have been compared with those of the well-known chemotherapeutic drug daunomycin, which is a non-threading classical intercalator bearing structural similarity to nogalamycin. A comparative AFM assessment revealed a greater increase in DNA contour length over the entire incubation period of 48 h for nogalamycin treatment, whereas the contour length increase manifested faster in case of daunomycin. The elastic response of single DNA molecules to an externally applied force was investigated by the single molecule AFS approach. Characteristic mechanical fingerprints in the overstretching behaviour clearly distinguished the nogalamycin/daunomycin-treated dsDNA from untreated dsDNA-the former appearing less elastic than the latter, and the nogalamycin-treated DNA distinguished from the daunomycin-treated DNA-the classically intercalated dsDNA appearing the least elastic. A single molecule AFS-based discrimination of threading intercalation from the classical type is being reported for the first time.

  5. Immobilized Tannin from Sanseviera trifasciata on Carbon as Adsorbent For Iron(II in Polluted Water Source

    Directory of Open Access Journals (Sweden)

    Irfan Hanafi Arif

    2016-03-01

    Full Text Available The organic-agricultural waste resulted from local farmer or community gardening recently paid public attention. The presence and easily grown of “Lidah Mertua” or Sanseviera trifasciata being focused on potency investigation for its prospecting application. It was reported contain some phenolic and also tannin extracted from aqueous solvents. This paper revealed recent investigation applying of its isolated tannin from leave part to modifying of activated carbon. The previous report published that carbon were able to adsorb some toxic heavy metals. However, it has some limitation including lower capacity adsorption. Impregnated or immobilized the tannin-isolated from S. trifasciata leaves was able to modify the carbon functionality, physical appearance, pores size, and it adsorption capacity. Both Langmuir and Freundlich adsorption mechanism model also disclosed the developed adsorbent mechanism of iron(II adsorption on the adsorbent tannin-immobolized on carbon. The real test using community well drilling water source also gave important finding on the concentration of iron(II contained on water source.

  6. Ternary iron(II) complex with an emissive imidazopyridine arm from Schiff base cyclizations and its oxidative DNA cleavage activity.

    Science.gov (United States)

    Mukherjee, Arindam; Dhar, Shanta; Nethaji, Munirathinam; Chakravarty, Akhil R

    2005-01-21

    The ternary iron(II) complex [Fe(L')(L")](PF6)3(1) as a synthetic model for the bleomycins, where L' and L" are formed from metal-mediated cyclizations of N,N'-(2-hydroxypropane-1,3-diyl)bis(pyridine-2-aldimine)(L), is synthesized and structurally characterized by X-ray crystallography. In the six-coordinate iron(ii) complex, ligands L' and L" show tetradentate and bidentate chelating modes of bonding. Ligand L' is formed from an intramolecular attack of the alcoholic OH group of L to one imine moiety leading to the formation of a stereochemically constrained five-membered ring. Ligand L" which is formed from an intermolecular reaction involving one imine moiety of L and pyridine-2-carbaldehyde has an emissive cationic imidazopyridine pendant arm. The complex binds to double-stranded DNA in the minor groove giving a Kapp value of 4.1 x 10(5) M(-1) and displays oxidative cleavage of supercoiled DNA in the presence of H2O2 following a hydroxyl radical pathway. The complex also shows photo-induced DNA cleavage activity on UV light exposure involving formation of singlet oxygen as the reactive species.

  7. Effects of Selected Dietary Secondary Metabolites on Reactive Oxygen Species Production Caused by Iron(II Autoxidation

    Directory of Open Access Journals (Sweden)

    Vladimir Chobot

    2014-12-01

    Full Text Available Iron is an essential co-factor for many enzymes that catalyze electron transfer reactions. It is well known that so-called “poorly liganded” iron can increase ROS concentrations and trigger oxidative stress that is capable of initiating apoptosis. Conversely, controlled ROS production has been recognized as an integral part of cellular signaling. Elevated ROS concentrations are associated with aging, inflammatory and degenerative diseases. Anti-aging properties have been attributed especially to antioxidant phenolic plant metabolites that represent food additives in our diet. Consequently, this study explores the effects of flavonoids (quercetin and rutin, several phenolic acids (caffeic, chlorogenic, and protocatechuic acid, and the alkaloid caffeine on iron(II autoxidation and ROS production in comparison to the standard antioxidants ascorbic acid and Trolox. The iron(II autoxidation assay was carried out in pH 6.0 (plant apoplast and inflamed human tissue and 7.4 (cell cytoplasm and human blood plasma. The obtained results accentuate phenolic acids as the more specific antioxidants compared to ascorbic acid and Trolox. Flavonoid redox chemistry depends more on the chemical milieu, specifically on pH. In vivo, the presence of iron cannot be ruled out and “wrongly” or “poorly” complexed iron has been pointed out as causative agent of various age-related diseases.

  8. Synthesis, characterization, and reactivity of furan- and thiophene-functionalized bis(n-heterocyclic carbene) complexes of iron(II)

    KAUST Repository

    Rieb, Julia

    2014-09-15

    The synthesis of iron(II) complexes bearing new heteroatom-functionalized methylene-bridged bis(N-heterocyclic carbene) ligands is reported. All complexes are characterized by single-crystal X-ray diffraction (SC-XRD), nuclear magnetic resonance (NMR) spectroscopy, and elemental analysis. Tetrakis(acetonitrile)-cis-[bis(o-imidazol-2-ylidenefuran)methane]iron(II) hexafluorophosphate (2a) and tetrakis(acetonitrile)-cis-[bis(o-imidazol-2-ylidenethiophene)methane]iron(II) hexafluorophosphate (2b) were obtained by aminolysis of [Fe{N(SiMe3)2}2(THF)] with furan- and thiophene-functionalized bis(imidazolium) salts 1a and 1b in acetonitrile. The SC-XRD structures of 2a and 2b show coordination of the bis(carbene) ligand in a bidentate fashion instead of a possible tetradentate coordination. The four other coordination sites of these distorted octahedral complexes are occupied by acetonitrile ligands. Crystallization of 2a in an acetone solution by the slow diffusion of Et2O led to the formation of cisdiacetonitriledi[ bis(o-imidazol-2-ylidenefuran)methane]iron(II) hexafluorophosphate (3a) with two bis(carbene) ligands coordinated in a bidentate manner and two cis-positioned acetonitrile molecules. Compounds 2a and 2b are the first reported iron(II) carbene complexes with four coordination sites occupied by solvent molecules, and it was demonstrated that those solvent ligands can undergo ligand-exchange reactions.

  9. Dimerization of Terminal Aryl Alkynes Catalyzed by Iron(II) Amine-Pyrazolyl Tripodal Complexes with E/Z Selectivity Controlled by tert-Butoxide

    KAUST Repository

    Xue, Fei

    2018-05-09

    The catalytic activity of iron(II) complexes with functionalized amine-pyrazolyl tripodal ligands toward dimerization of terminal alkynes in the presence a base (KOtBu or NaOtBu) has been studied. An unusual E/Z selectivity of the reaction determined by tert-butoxide was observed.

  10. Update: An efficient synthesis of poly(ethylene glycol)-supported iron(II) porphyrin using a click reaction and its application for the catalytic olefination of aldehydes

    KAUST Repository

    Chinnusamy, Tamilselvi R.; Rodionov, Valentin; Kü hn, Fritz; Reiser, Oliver

    2012-01-01

    The facile synthesis of polyethylene glycol (PEG)-immobilized iron(II) porphyrin using a copper-catalyzed azide-alkyne [3+2] cycloaddition "click" reaction is reported. The prepared complex 5 (PEG-C 51H 39FeN 7O) was found to be an efficient

  11. Electrochemical characterization of mixed self-assembled films of water-soluble single-walled carbon nanotube-poly(m-aminobenzene sulfonic acid) and Iron(II) tetrasulfophthalocyanine

    CSIR Research Space (South Africa)

    Agboola, BO

    2010-09-01

    Full Text Available The redox activities of water-soluble iron(II) tetrasulfophthalocyanine (FeTSPc) and single-walled carbon nanotube-poly(m-aminobenzene sulfonic acid) (SWCNT-PABS) adsorbed on a gold surface precoated with a self-assembled monolayer (SAM) of 2...

  12. Dimerization of Terminal Aryl Alkynes Catalyzed by Iron(II) Amine-Pyrazolyl Tripodal Complexes with E/Z Selectivity Controlled by tert-Butoxide

    KAUST Repository

    Xue, Fei; Song, Xiaolu; Lin, Ting Ting; Munkerup, Kristin; Albawardi, Saad Fahad; Huang, Kuo-Wei; Hor, T. S. Andy; Zhao, Jin

    2018-01-01

    The catalytic activity of iron(II) complexes with functionalized amine-pyrazolyl tripodal ligands toward dimerization of terminal alkynes in the presence a base (KOtBu or NaOtBu) has been studied. An unusual E/Z selectivity of the reaction determined by tert-butoxide was observed.

  13. Intercalation of metals and silicon at the interface of epitaxial graphene and its substrates

    International Nuclear Information System (INIS)

    Huang Li; Xu Wen-Yan; Que Yan-De; Mao Jin-Hai; Meng Lei; Pan Li-Da; Li Geng; Wang Ye-Liang; Du Shi-Xuan; Gao Hong-Jun; Liu Yun-Qi

    2013-01-01

    Intercalations of metals and silicon between epitaxial graphene and its substrates are reviewed. For metal intercalation, seven different metals have been successfully intercalated at the interface of graphene/Ru(0001) and form different intercalated structures. Meanwhile, graphene maintains its original high quality after the intercalation and shows features of weakened interaction with the substrate. For silicon intercalation, two systems, graphene on Ru(0001) and on Ir(111), have been investigated. In both cases, graphene preserves its high quality and regains its original superlative properties after the silicon intercalation. More importantly, we demonstrate that thicker silicon layers can be intercalated at the interface, which allows the atomic control of the distance between graphene and the metal substrates. These results show the great potential of the intercalation method as a non-damaging approach to decouple epitaxial graphene from its substrates and even form a dielectric layer for future electronic applications. (topical review - low-dimensional nanostructures and devices)

  14. Alkali metal and alkali metal hydroxide intercalates of the layered transition metal disulfides

    International Nuclear Information System (INIS)

    Kanzaki, Y.; Konuma, M.; Matsumoto, O.

    1981-01-01

    The intercalation reaction of some layered transition metal disulfides with alkali metals, alkali metal hydroxides, and tetraalkylammonium hydroxides were investigated. The alkali metal intercalates were prepared in the respective metal-hexamethylphosphoric triamide solutions in vaccuo, and the hydroxide intercalates in aqueous hydroxide solutions. According to the intercalation reaction, the c-lattice parameter was increased, and the increase indicated the expansion of the interlayer distance. In the case of alkali metal intercalates, the expansion of the interlayer distance increased continuously, corresponding to the atomic radius of the alkali metal. On the other hand, the hydroxide intercalates showed discrete expansion corresponding to the effective ionic radius of the intercalated cation. All intercalates of TaS 2 amd NbS 2 were superconductors. The expansion of the interlayer distance tended to increase the superconducting transition temperature in the intercalates of TaS 2 and vice versa in those of NbS 2 . (orig.)

  15. Extraction of iron(III) with diphenyl-2-pyridylmethane dissolved in benzene from aqueous chloride solutions

    International Nuclear Information System (INIS)

    Suhail Ahmed; Shamas-Ud-Zuha; Abdul Ghafoor; Ejaz, M.

    1978-01-01

    The mechanism of extraction has been investigated by partition, slope analysis and loading-ratio data. The results obtained give a picture of the mechanism of extraction of FeCl 4 - ions in relation to the hydration and solvation of the compound extracted. The possible formula of the extracted species is (DPPM)sub(3)Hsub(3)Osup(+)(Hsub(2)O)sub(n)-FeClsub(4)sup(-). In dilute aqueous hydrochloric acid systems the influence of the concentration of a number of salts with cations of different electrical potentials (Ze/r), on iron(III) extraction, has been studied. Splitting of the organic phases occurs at high acid and/or high salt concentrations. The phenomenon is explained on the basis of the variability of the hydration number. Investigations have been made to understand the parameters controlling the extraction of the metal and it is shown that the extraction offers a simple, fast and selective separation method of iron from solutions. (author)

  16. A Novel Sensor for Monitoring of Iron(III) Ions Based on Porphyrins

    Science.gov (United States)

    Vlascici, Dana; Fagadar-Cosma, Eugenia; Popa, Iuliana; Chiriac, Vlad; Gil-Agusti, Mayte

    2012-01-01

    Three A3B porphyrins with mixed carboxy-, phenoxy-, pyridyl-, and dimethoxy-substituent functionalization on the meso-phenyl groups were obtained by multicomponent synthesis, fully characterized and used as ionophores for preparing PVC-based membrane sensors selective to iron(III). The membranes have an ionophore:PVC:plasticizer composition ratio of 1:33:66. Sodium tetraphenylborate was used as additive (20 mol% relative to ionophore). The performance characteristics (linear concentration range, slope and selectivity) of the sensors were investigated. The best results were obtained for the membrane based on 5-(4-carboxyphenyl)-10,15,20-tris(4-phenoxyphenyl)-porphyrin plasticized with bis(2-ethylhexyl)sebacate, in a linear range from 1 × 10−7–1 × 10−1 M with a slope of 21.6 mV/decade. The electrode showed high selectivity with respect to alkaline and heavy metal ions and a response time of 20 s. The influence of pH on the sensor response was studied. The sensor was used for a period of six weeks and the utility has been tested for the quantitative determination of Fe(III) in recovered solutions from spent lithium ion batteries and for the quantitative determination of Fe(III) in tap water samples. PMID:22969395

  17. Crystal structures and Moessbauer spectra of spin-crossover iron(III) complexes of quinquedentate ligands

    International Nuclear Information System (INIS)

    Maeda, Yonezo; Noda, Yosuke; Oshio, Hiroki; Takashima, Yoshimasa; Matsumoto, Naohide

    1994-01-01

    Magnetic properties, Moessbauer spectra and crystal structures of spin-crossover iron(III) complexes with a quinquedentate ligand [FeLX]BPh 4 are reported. X and L denote a unidentate ligand and a quinquedentate ligand, respectively. [Fe(mbpN)(im)]BPh 4 shows spin-crossover behavior in an appropriate organic solvent, and [Fe(mbpN)(lut)]BPh 4 , [Fe(bpN)(py)]BPh 4 and [Fe(salten)X]BPh 4 (X = 4me-py or 2me-im) show spin-crossover behavior in a solid and in an organic solvent. It was found that the ligand field strength of salten was stronger than that of mbpN. The rates of spin-state interexchange in the complexes are as fast as the inverse of the lifetime (1 x 10 -7 s) of the Moessbauer nuclear level. The Moessbauer spectroscopic behavior of [Fe(mbpN)(lut)]BPh 4 and [Fe(bpN)(py)]BPh 4 is different to that of [Fe(salten)X]BPh 4 (X = 4me-py or 2me-im). The difference was ascribed to the different geometrical positions of the corresponding anions. (orig.)

  18. Nitrogen loss from anaerobic ammonium oxidation coupled to Iron(III) reduction in a riparian zone.

    Science.gov (United States)

    Ding, Bangjing; Li, Zhengkui; Qin, Yunbin

    2017-12-01

    Anaerobic ammonium oxidation coupled to iron(III) reduction (termed Feammox) is a recently discovered pathway of nitrogen cycling. However, little is known about the pathways of N transformation via Feammox process in riparian zones. In this study, evidence for Feammox in riparian zones with or without vegetation cover was demonstrated using isotope tracing technique and high-throughput sequencing technology. The results showed that Feammox could occur in riparian zones, and demonstrated that N 2 directly from Feammox was dominant Feammox pathway. The Feammox rates in vegetated soil samples was 0.32-0.37 mg N kg -1 d -1 , which is higher than that in un-vegetated soil samples (0.20 mg N kg -1 d -1 ). Moreover, the growth of vegetation led to a 4.99-6.41% increase in the abundance of iron reducing bacteria (Anaeromyxobacter, Pseudomonas and Geobacter) and iron reducing bacteria play an essential role in Feammox process. An estimated loss of 23.7-43.9 kg N ha -1 year -1 was associated with Feammox in the examined riparian zone. Overall, the co-occurrence of ammonium oxidation and iron reduction suggest that Feammox can play an essential role in the pathway of nitrogen removal in riparian zones. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Efficient catalytic cycloalkane oxidation employing a "helmet" phthalocyaninato iron(III) complex.

    Science.gov (United States)

    Brown, Elizabeth S; Robinson, Jerome R; McCoy, Aaron M; McGaff, Robert W

    2011-06-14

    We have examined the catalytic activity of an iron(III) complex bearing the 14,28-[1,3-diiminoisoindolinato]phthalocyaninato (diiPc) ligand in oxidation reactions with three substrates (cyclohexane, cyclooctane, and indan). This modified metallophthalocyaninato complex serves as an efficient and selective catalyst for the oxidation of cyclohexane and cyclooctane, and to a far lesser extent indan. In the oxidations of cyclohexane and cyclooctane, in which hydrogen peroxide is employed as the oxidant under inert atmosphere, we have observed turnover numbers of 100.9 and 122.2 for cyclohexanol and cyclooctanol, respectively. The catalyst shows strong selectivity for alcohol (vs. ketone) formation, with alcohol to ketone (A/K) ratios of 6.7 and 21.0 for the cyclohexane and cyclooctane oxidations, respectively. Overall yields (alcohol + ketone) were 73% for cyclohexane and 92% for cyclooctane, based upon the total hydrogen peroxide added. In the catalytic oxidation of indan under similar conditions, the TON for 1-indanol was 10.1, with a yield of 12% based upon hydrogen peroxide. No 1-indanone was observed in the product mixture.

  20. Iron(III Fluorinated Porphyrins: Greener Chemistry from Synthesis to Oxidative Catalysis Reactions

    Directory of Open Access Journals (Sweden)

    Susana L. H. Rebelo

    2016-04-01

    Full Text Available Iron(III fluorinated porphyrins play a central role in the biomimetics of heme enzymes and enable cleaner routes to the oxidation of organic compounds. The present work reports significant improvements in the eco-compatibility of the synthesis of 5,10,15,20-tetrakis-pentafluorophenylporphyrin (H2TPFPP and the corresponding iron complex [Fe(TPFPPCl], and the use of [Fe(TPFPPCl] as an oxidation catalyst in green conditions. The preparations of H2TPFPP and [Fe(TPFPPCl] typically use toxic solvents and can be made significantly greener and simpler using microwave heating and optimization of the reaction conditions. In the optimized procedure it was possible to eliminate nitrobenzene from the porphyrin synthesis and replace DMF by acetonitrile in the metalation reaction, concomitant with a significant reduction of reaction time and simplification of the purification procedure. The Fe(IIIporphyrin is then tested as catalyst in the selective oxidation of aromatics at room temperature using a green oxidant (hydrogen peroxide and green solvent (ethanol. Efficient epoxidation of indene and selective oxidation of 3,5-dimethylphenol and naphthalene to the corresponding quinones is observed.

  1. Iron(III) Fluorinated Porphyrins: Greener Chemistry from Synthesis to Oxidative Catalysis Reactions.

    Science.gov (United States)

    Rebelo, Susana L H; Silva, André M N; Medforth, Craig J; Freire, Cristina

    2016-04-12

    Iron(III) fluorinated porphyrins play a central role in the biomimetics of heme enzymes and enable cleaner routes to the oxidation of organic compounds. The present work reports significant improvements in the eco-compatibility of the synthesis of 5,10,15,20-tetrakis-pentafluorophenylporphyrin (H₂TPFPP) and the corresponding iron complex [Fe(TPFPP)Cl], and the use of [Fe(TPFPP)Cl] as an oxidation catalyst in green conditions. The preparations of H₂TPFPP and [Fe(TPFPP)Cl] typically use toxic solvents and can be made significantly greener and simpler using microwave heating and optimization of the reaction conditions. In the optimized procedure it was possible to eliminate nitrobenzene from the porphyrin synthesis and replace DMF by acetonitrile in the metalation reaction, concomitant with a significant reduction of reaction time and simplification of the purification procedure. The Fe(III)porphyrin is then tested as catalyst in the selective oxidation of aromatics at room temperature using a green oxidant (hydrogen peroxide) and green solvent (ethanol). Efficient epoxidation of indene and selective oxidation of 3,5-dimethylphenol and naphthalene to the corresponding quinones is observed.

  2. A novel sensor for monitoring of iron(III) ions based on porphyrins.

    Science.gov (United States)

    Vlascici, Dana; Fagadar-Cosma, Eugenia; Popa, Iuliana; Chiriac, Vlad; Gil-Agusti, Mayte

    2012-01-01

    Three A(3)B porphyrins with mixed carboxy-, phenoxy-, pyridyl-, and dimethoxy-substituent functionalization on the meso-phenyl groups were obtained by multicomponent synthesis, fully characterized and used as ionophores for preparing PVC-based membrane sensors selective to iron(III). The membranes have an ionophore:PVC:plasticizer composition ratio of 1:33:66. Sodium tetraphenylborate was used as additive (20 mol% relative to ionophore). The performance characteristics (linear concentration range, slope and selectivity) of the sensors were investigated. The best results were obtained for the membrane based on 5-(4-carboxyphenyl)-10,15,20-tris(4-phenoxyphenyl)-porphyrin plasticized with bis(2-ethylhexyl)sebacate, in a linear range from 1 × 10(-7)-1 × 10(-1) M with a slope of 21.6 mV/decade. The electrode showed high selectivity with respect to alkaline and heavy metal ions and a response time of 20 s. The influence of pH on the sensor response was studied. The sensor was used for a period of six weeks and the utility has been tested for the quantitative determination of Fe(III) in recovered solutions from spent lithium ion batteries and for the quantitative determination of Fe(III) in tap water samples.

  3. Organoelemental intercalation compounds in the system PbI2-ethan olamine

    International Nuclear Information System (INIS)

    Gurina, G.I.; Evtushenko, V.D.; Muraeva, O.A.; Ignatyuk, V.P.; Koshkin, V.M.

    1985-01-01

    Two intercalation phases with different stoichiometry in system PbI 2 -ethanolamine are identified, using the methods of IR spectroscopy, spectroscopy of diffusion reflection, X-ray phase and thermogravimetric analyses. Formation kinetics of intercalation compounds in the system, having two phases, differing in the content of intercalant in the matrix layers, is studied. In conformity with thermodynamic theory of intercalation, it is shown experimentally, that the value of a charge, transferred from intercalant molecules to the matrix layer, decreases with the increase in intercalant content in interlayer spaces

  4. Decreasing the electronic confinement in layered perovskites through intercalation.

    Science.gov (United States)

    Smith, Matthew D; Pedesseau, Laurent; Kepenekian, Mikaël; Smith, Ian C; Katan, Claudine; Even, Jacky; Karunadasa, Hemamala I

    2017-03-01

    We show that post-synthetic small-molecule intercalation can significantly reduce the electronic confinement of 2D hybrid perovskites. Using a combined experimental and theoretical approach, we explain structural, optical, and electronic effects of intercalating highly polarizable molecules in layered perovskites designed to stabilize the intercalants. Polarizable molecules in the organic layers substantially alter the optical and electronic properties of the inorganic layers. By calculating the spatially resolved dielectric profiles of the organic and inorganic layers within the hybrid structure, we show that the intercalants afford organic layers that are more polarizable than the inorganic layers. This strategy reduces the confinement of excitons generated in the inorganic layers and affords the lowest exciton binding energy for an n = 1 perovskite of which we are aware. We also demonstrate a method for computationally evaluating the exciton's binding energy by solving the Bethe-Salpeter equation for the exciton, which includes an ab initio determination of the material's dielectric profile across organic and inorganic layers. This new semi-empirical method goes beyond the imprecise phenomenological approximation of abrupt dielectric-constant changes at the organic-inorganic interfaces. This work shows that incorporation of polarizable molecules in the organic layers, through intercalation or covalent attachment, is a viable strategy for tuning 2D perovskites towards mimicking the reduced electronic confinement and isotropic light absorption of 3D perovskites while maintaining the greater synthetic tunability of the layered architecture.

  5. Manipulation of Dirac cones in metal-intercalated epitaxial graphene

    Science.gov (United States)

    Wang, Cai-Zhuang; Kim, Minsung; Tringides, Michael; Ho, Kai-Ming

    Graphene is one of the most attractive materials from both fundamental and practical points of view due to its characteristic Dirac cones. The electronic property of graphene can be modified through the interaction with substrate or another graphene layer as illustrated in few-layer epitaxial graphene. Recently, metal intercalation became an effective method to manipulate the electronic structure of graphene by modifying the coupling between the constituent layers. In this work, we show that the Dirac cones of epitaxial graphene can be manipulated by intercalating rare-earth metals. We demonstrate that rare-earth metal intercalated epitaxial graphene has tunable band structures and the energy levels of Dirac cones as well as the linear or quadratic band dispersion can be controlled depending on the location of the intercalation layer and density. Our results could be important for applications and characterizations of the intercalated epitaxial graphene. Supported by the U.S. DOE-BES under Contract No. DE-AC02-07CH11358.

  6. Intercalation and Exfoliation of Kaolinite with Sodium Dodecyl Sulfate

    Directory of Open Access Journals (Sweden)

    Xiaochao Zuo

    2018-03-01

    Full Text Available Kaolinite (Kaol was intercalated with dimethyl sulfoxide (DMSO and subsequently methanol (MeOH to prepare intercalation compounds Kaol-DMSO and Kaol-MeOH. Kaol-MeOH was used as an intermediate to synthesize Kaol-sodium dodecyl sulfate (SDS intercalation compound (Kaol-SDS via displacement reaction. The ultrasonic exfoliation of Kaol-SDS produced a resultant Kaol-SDS-U. The samples were characterized by X-ray diffraction (XRD, Fourier transformation infrared spectroscopy (FTIR, thermal analysis, scanning electronic microscopy (SEM, transmission electron microscopy (TEM and particle size analysis. The results revealed that the intercalation of sodium dodecyl sulfate into kaolinite layers caused an obvious increase of the basal spacing from 0.72–4.21 nm. The dehydroxylation temperature of Kaol-SDS was obviously lower than that of original kaolinite. During the intercalation process of sodium dodecyl sulfate, a few kaolinite layers were exfoliated and curled up from the edges of the kaolinite sheets. After sonication treatment, the kaolinite layers were further transformed into nanoscrolls, and the exfoliated resultant Kaol-SDS-U possessed a smaller particle size close to nanoscale.

  7. Highly n -doped graphene generated through intercalated terbium atoms

    Science.gov (United States)

    Daukiya, L.; Nair, M. N.; Hajjar-Garreau, S.; Vonau, F.; Aubel, D.; Bubendorff, J. L.; Cranney, M.; Denys, E.; Florentin, A.; Reiter, G.; Simon, L.

    2018-01-01

    We obtained highly n -type doped graphene by intercalating terbium atoms between graphene and SiC(0001) through appropriate annealing in ultrahigh vacuum. After terbium intercalation angle-resolved-photoelectron spectroscopy (ARPES) showed a drastic change in the band structure around the K points of the Brillouin zone: the well-known conical dispersion band of a graphene monolayer was superposed by a second conical dispersion band of a graphene monolayer with an electron density reaching 1015cm-2 . In addition, we demonstrate that atom intercalation proceeds either below the buffer layer or between the buffer layer and the monolayer graphene. The intercalation of terbium below a pure buffer layer led to the formation of a highly n -doped graphene monolayer decoupled from the SiC substrate, as evidenced by ARPES and x-ray photoelectron spectroscopy measurements. The band structure of this highly n -doped monolayer graphene showed a kink (a deviation from the linear dispersion of the Dirac cone), which has been associated with an electron-phonon coupling constant one order of magnitude larger than those usually obtained for graphene with intercalated alkali metals.

  8. Investigating the Intercalation Chemistry of Alkali Ions in Fluoride Perovskites

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Tanghong; Chen, Wei; Cheng, Lei; Bayliss, Ryan D.; Lin, Feng; Plews, Michael R.; Nordlund, Dennis; Doeff, Marca M.; Persson, Kristin A.; Cabana, Jordi (LBNL); (SLAC); (UIC); (UCB)

    2017-02-07

    Reversible intercalation reactions provide the basis for modern battery electrodes. Despite decades of exploration of electrode materials, the potential for materials in the nonoxide chemical space with regards to intercalation chemistry is vast and rather untested. Transition metal fluorides stand out as an obvious target. To this end, we report herein a new family of iron fluoride-based perovskite cathode materials AxK1–xFeF3 (A = Li, Na). By starting with KFeF3, approximately 75% of K+ ions were subsequently replaced by Li+ and Na+ through electrochemical means. X-ray diffraction and Fe X-ray absorption spectroscopy confirmed the existence of intercalation of alkali metal ions in the perovskite structure, which is associated with the Fe2+/3+ redox couple. A computational study by density functional theory showed agreement with the structural and electrochemical data obtained experimentally, which suggested the possibility of fluoride-based materials as potential intercalation electrodes. This study increases our understanding of the intercalation chemistry of ternary fluorides, which could inform efforts toward the exploration of new electrode materials.

  9. Understanding Mn-Based Intercalation Cathodes from Thermodynamics and Kinetics

    Directory of Open Access Journals (Sweden)

    Yin Xie

    2017-07-01

    Full Text Available A series of Mn-based intercalation compounds have been applied as the cathode materials of Li-ion batteries, such as LiMn2O4, LiNi1−x−yCoxMnyO2, etc. With open structures, intercalation compounds exhibit a wide variety of thermodynamic and kinetic properties depending on their crystal structures, host chemistries, etc. Understanding these materials from thermodynamic and kinetic points of view can facilitate the exploration of cathodes with better electrochemical performances. This article reviews the current available thermodynamic and kinetic knowledge on Mn-based intercalation compounds, including the thermal stability, structural intrinsic features, involved redox couples, phase transformations as well as the electrical and ionic conductivity.

  10. The preliminary feasibility of intercalated graphite railgun armatures

    International Nuclear Information System (INIS)

    Gaier, J.R.; Yashan, D.; Naud, S.

    1991-01-01

    This paper reports on graphite intercalation compounds which may provide an excellent material for the fabrication of electro-magnetic railgun armatures. As a pulse of power is fed into the armature the intercalate could be excited into the plasma state around the edges of the armature, while the bulk of the current would be carried through the graphite block. Such an armature would have desirable characteristics of both diffuse plasma armatures and bulk conduction armatures. In addition, the highly anisotropic nature of these materials could enable the electrical and thermal conductivity to be tailored to meet the specific requirements of electromagnetic railgun armatures. Preliminary investigations have been performed in an attempt to determine the feasibility of using graphite intercalation compounds as railgun armatures. Issues of fabrication, resistivity, stability, and electrical current spreading have been addressed for the case of highly oriented pyrolytic graphite

  11. New kaolinite phases expanded through intercalation with potassium acetate

    International Nuclear Information System (INIS)

    Frost, R.L.; Kristof, J.; Kloprogge, J.T.

    1998-01-01

    Full text: Changes in the hydroxyl surfaces of potassium acetate-intercalated kaolinite have been studied over the ambient to predehydroxylation temperature range using a combination of X-ray diffraction and Raman spectroscopy. Upon intercalation, the kaolinite expanded along the c-axis direction to 13.88 Angstroms. Upon heating the intercalation complex over the 50 to 300 deg C range, X-ray diffraction shows the existence of three additional intercalation phases with d-spacings of 9.09, 9.60, and 11.47 Angstroms. The amount of each phase is temperature dependent. These expansions are reversible and upon cooling the intercalation complex returned to its original spacing. The 13.88 Angstroms phase only existed in the presence of water. It is proposed that the expanded kaolinite intercalation phases result from the orientation of the acetate within the intercalation complex. The Raman spectra of the hydroxyl-stretching region (Frost and van der Gaast, 1997) of potassium acetate-intercalated kaolinite has been obtained under an atmosphere of both air and nitrogen using a thermal stage over the 25 to 300 deg C temperature range (Johansson et al., 1998). Raman spectra of the C-C, C=O stretching and O-C-O bending modes show that at least two types of acetate are present in the intercalation complex. These are assigned to two different orientations of the acetate. At 25 deg C, a new band at 3606 cm -1 attributed to the inner surface hydroxyl hydrogen bonded to the acetate ion is observed with a concomitant loss of intensity in the bands attributed to the inner surface hydroxyls (Frost and Kristof, 1997, Frost et al.,1997). Heating the intercalation complex to 50 deg C results in two hydroxyl-stretching frequencies at 3594 and 3604 cm -1 . This change in frequencies is ascribed to phase changes of the potassium acetate-intercalated kaolinite. At 100 deg C, the bands shift to 3600 and 3613 cm -1 . These shifts in frequencies are assigned to new kaolinite expanded phases. At

  12. Scientific Opinion on the safety of the complexation product of sodium tartrate and iron(III) chloride as a food additive

    OpenAIRE

    2015-01-01

    The complexation product of sodium tartrates and iron(III) chloride (Fe mTA) is proposed for use as an anti-caking agent, only in salt or its substitutes, with a maximum use level of 106 mg Fe mTA/kg salt. Fe mTA can be expected to dissociate into its constituent iron(III) and tartrate components upon ingestion. Studies in rats demonstrated that up to 90 % of ingested DL-tartrate or tartaric acid were absorbed, studies in humans suggested that only 20 % of an ingested dose of tartaric acid we...

  13. Preparation of graphite intercalation compounds containing oligo and polyethers

    Science.gov (United States)

    Zhang, Hanyang; Lerner, Michael M.

    2016-02-01

    Layered host-polymer nanocomposites comprising polymeric guests between inorganic sheets have been prepared with many inorganic hosts, but there is limited evidence for the incorporation of polymeric guests into graphite. Here we report for the first time the preparation, and structural and compositional characterization of graphite intercalation compounds (GICs) containing polyether bilayers. The new GICs are obtained by either (1) reductive intercalation of graphite with an alkali metal in the presence of an oligo or polyether and an electrocatalyst, or (2) co-intercalate exchange of an amine for an oligo or polyether in a donor-type GIC. Structural characterization of products using powder X-ray diffraction, Raman spectroscopy, and thermal analyses supports the formation of well-ordered, first-stage GICs containing alkali metal cations and oligo or polyether bilayers between reduced graphene sheets.Layered host-polymer nanocomposites comprising polymeric guests between inorganic sheets have been prepared with many inorganic hosts, but there is limited evidence for the incorporation of polymeric guests into graphite. Here we report for the first time the preparation, and structural and compositional characterization of graphite intercalation compounds (GICs) containing polyether bilayers. The new GICs are obtained by either (1) reductive intercalation of graphite with an alkali metal in the presence of an oligo or polyether and an electrocatalyst, or (2) co-intercalate exchange of an amine for an oligo or polyether in a donor-type GIC. Structural characterization of products using powder X-ray diffraction, Raman spectroscopy, and thermal analyses supports the formation of well-ordered, first-stage GICs containing alkali metal cations and oligo or polyether bilayers between reduced graphene sheets. Electronic supplementary information (ESI) available: Domain size, additional Raman spectra info, compositional calculation, and packing fractions. See DOI: 10.1039/c5

  14. Intercalation of paracetamol into the hydrotalcite-like host

    International Nuclear Information System (INIS)

    Kovanda, František; Maryšková, Zuzana; Kovář, Petr

    2011-01-01

    Hydrotalcite-like compounds are often used as host structures for intercalation of various anionic species. The product intercalated with the nonionic, water-soluble pharmaceuticals paracetamol, N-(4-hydroxyphenyl)acetamide, was prepared by rehydration of the Mg–Al mixed oxide obtained by calcination of hydrotalcite-like precursor at 500 °C. The successful intercalation of paracetamol molecules into the interlayer space was confirmed by powder X-ray diffraction and infrared spectroscopy measurements. Molecular simulations showed that the phenolic hydroxyl groups of paracetamol interact with hydroxide sheets of the host via the hydroxyl groups of the positively charged sites of Al-containing octahedra; the interlayer water molecules are located mostly near the hydroxide sheets. The arrangement of paracetamol molecules in the interlayer is rather disordered and interactions between neighboring molecules cause their tilting towards the hydroxide sheets. Dissolution tests in various media showed slower release of paracetamol intercalated in the hydrotalcite-like host in comparison with tablets containing the powdered pharmaceuticals. - Graphical abstract: Molecular simulations showed disordered arrangement of paracetamol molecules in the interlayer; most of the interlayer water molecules are located near the hydroxide sheets.▪ Highlights: ► Paracetamol was intercalated in Mg–Al hydrotalcite-like host by rehydration/reconstruction procedure. ► Paracetamol phenolic groups interact with positively charged sites in hydroxide sheets. ► Molecular simulations showed disordered arrangement of guest molecules in the interlayer. ► Slower release of paracetamol intercalated in the hydrotalcite-like host was observed.

  15. Making oxidation potentials predictable: Coordination of additives applied to the electronic fine tuning of an iron(II) complex

    KAUST Repository

    Haslinger, Stefan

    2014-11-03

    This work examines the impact of axially coordinating additives on the electronic structure of a bioinspired octahedral low-spin iron(II) N-heterocyclic carbene (Fe-NHC) complex. Bearing two labile trans-acetonitrile ligands, the Fe-NHC complex, which is also an excellent oxidation catalyst, is prone to axial ligand exchange. Phosphine- and pyridine-based additives are used for substitution of the acetonitrile ligands. On the basis of the resulting defined complexes, predictability of the oxidation potentials is demonstrated, based on a correlation between cyclic voltammetry experiments and density functional theory calculated molecular orbital energies. Fundamental insights into changes of the electronic properties upon axial ligand exchange and the impact on related attributes will finally lead to target-oriented manipulation of the electronic properties and consequently to the effective tuning of the reactivity of bioinspired systems.

  16. Making oxidation potentials predictable: Coordination of additives applied to the electronic fine tuning of an iron(II) complex

    KAUST Repository

    Haslinger, Stefan; Kü ck, Jens W.; Hahn, Eva M.; Cokoja, Mirza; Pö thig, Alexander; Basset, Jean-Marie; Kü hn, Fritz

    2014-01-01

    This work examines the impact of axially coordinating additives on the electronic structure of a bioinspired octahedral low-spin iron(II) N-heterocyclic carbene (Fe-NHC) complex. Bearing two labile trans-acetonitrile ligands, the Fe-NHC complex, which is also an excellent oxidation catalyst, is prone to axial ligand exchange. Phosphine- and pyridine-based additives are used for substitution of the acetonitrile ligands. On the basis of the resulting defined complexes, predictability of the oxidation potentials is demonstrated, based on a correlation between cyclic voltammetry experiments and density functional theory calculated molecular orbital energies. Fundamental insights into changes of the electronic properties upon axial ligand exchange and the impact on related attributes will finally lead to target-oriented manipulation of the electronic properties and consequently to the effective tuning of the reactivity of bioinspired systems.

  17. Iron(II) tris(3-bromo-1,10-phenanthroline) complex:synthesis, crystal structure and electropolymerization

    CERN Document Server

    Lee, K J; Lee, S S; Lee, B Y

    2002-01-01

    The complex of iron(II) tris(3-Br-phen)(3-Br-phen; 3-bromo-1,10-phenanthroline) was prepared as a precursor of electropolymerization and the crystal structure of [Fe(3-Br-phen) sub 3](PF sub 6) sub 2 centre dot CH sub 3 CN with a distorted octahedral geometry has been investigated. The reductive electropolymerization of [Fe(3-Br-phen) sub 3] sup 2 sup + complex onto the surface of a glassy carbon electrode and indium tin oxide (ITO) optically transparent electrode were performed in acetonitrile at room temperature. Thin film of poly-[Fe(3-Br-phen) sub 3] sup 2 sup + formed was adherent, electroactive and stably deposited on a glassy carbon disk electrode. The thin metallopolymeric film formed was also confirmed by absorption spectroscopy.

  18. Intercalation of paracetamol into the hydrotalcite-like host

    Science.gov (United States)

    Kovanda, František; Maryšková, Zuzana; Kovář, Petr

    2011-12-01

    Hydrotalcite-like compounds are often used as host structures for intercalation of various anionic species. The product intercalated with the nonionic, water-soluble pharmaceuticals paracetamol, N-(4-hydroxyphenyl)acetamide, was prepared by rehydration of the Mg-Al mixed oxide obtained by calcination of hydrotalcite-like precursor at 500 °C. The successful intercalation of paracetamol molecules into the interlayer space was confirmed by powder X-ray diffraction and infrared spectroscopy measurements. Molecular simulations showed that the phenolic hydroxyl groups of paracetamol interact with hydroxide sheets of the host via the hydroxyl groups of the positively charged sites of Al-containing octahedra; the interlayer water molecules are located mostly near the hydroxide sheets. The arrangement of paracetamol molecules in the interlayer is rather disordered and interactions between neighboring molecules cause their tilting towards the hydroxide sheets. Dissolution tests in various media showed slower release of paracetamol intercalated in the hydrotalcite-like host in comparison with tablets containing the powdered pharmaceuticals.

  19. K-intercalated carbon systems: Effects of dimensionality and substrate

    KAUST Repository

    Kaloni, Thaneshwor P.; Kahaly, M. Upadhyay; Cheng, Yingchun; Schwingenschlö gl, Udo

    2012-01-01

    the charge carrier density. Reasonably high values are found for all systems, the highest carrier density for the bilayer. The band structure and electron-phonon coupling of free-standing K-intercalated bilayer graphene points to a high probability

  20. Structural, energetic and electronic properties of intercalated boron ...

    Indian Academy of Sciences (India)

    2National Institute for R&D of Isotopic and Molecular Technologies, Cluj-Napoca 400 293, Romania. MS received 8 November 2010; revised 28 March 2012. Abstract. The effects of chirality and the intercalation of transitional metal atoms inside single walled BN nano- tubes on structural, energetic and electronic properties ...

  1. Preparation of intercalated polyaniline/clay nanocomposite and its

    Indian Academy of Sciences (India)

    Intercalated composite of polyaniline and clay has been reported. The composite was prepared by in situ polymerization of aniline within the layers of `illite' clay. The composite was characterized for its structural, spectral, and microscopic properties. At higher level of loading the layered structure of composite breaks ...

  2. Enantiospecific kinking of DNA by a partially intercalating metal complex

    KAUST Repository

    Reymer, Anna

    2012-01-01

    Opposite enantiomers of [Ru(phenanthroline) 3] 2+ affect the persistence length of DNA differently, a long speculated effect of helix kinking. Our molecular dynamics simulations confirm a substantial change of duplex secondary structure produced by wedge-intercalation of one but not the other enantiomer. This effect is exploited by several classes of DNA operative proteins. © The Royal Society of Chemistry 2012.

  3. Capacitive Sensing of Intercalated H2O Molecules Using Graphene.

    Science.gov (United States)

    Olson, Eric J; Ma, Rui; Sun, Tao; Ebrish, Mona A; Haratipour, Nazila; Min, Kyoungmin; Aluru, Narayana R; Koester, Steven J

    2015-11-25

    Understanding the interactions of ambient molecules with graphene and adjacent dielectrics is of fundamental importance for a range of graphene-based devices, particularly sensors, where such interactions could influence the operation of the device. It is well-known that water can be trapped underneath graphene and its host substrate; however, the electrical effect of water beneath graphene and the dynamics of how the interfacial water changes with different ambient conditions has not been quantified. Here, using a metal-oxide-graphene variable-capacitor (varactor) structure, we show that graphene can be used to capacitively sense the intercalation of water between graphene and HfO2 and that this process is reversible on a fast time scale. Atomic force microscopy is used to confirm the intercalation and quantify the displacement of graphene as a function of humidity. Density functional theory simulations are used to quantify the displacement of graphene induced by intercalated water and also explain the observed Dirac point shifts as being due to the combined effect of water and oxygen on the carrier concentration in the graphene. Finally, molecular dynamics simulations indicate that a likely mechanism for the intercalation involves adsorption and lateral diffusion of water molecules beneath the graphene.

  4. Intercalation of papain enzyme into hydrotalcite type layered double hydroxide

    Science.gov (United States)

    Zou, N.; Plank, J.

    2012-09-01

    Intercalation of proteolytic enzyme papain into hydrotalcite type LDH structure was achieved by controlled co-precipitation at pH=9.0 in the presence of papain. Characterization of the MgAl-papain-LDH phase was carried out using X-ray powder diffraction (XRD), elemental analysis, infrared spectroscopy (IR) and thermogravimetry (TG). According to XRD, papain was successfully intercalated. The d-value for the basal spacing of MgAl-papain-LDH was found at ˜5.3 nm. Consequently, original papain (hydrodynamic diameter ˜7.2 nm) attains a compressed conformation during intercalation.Formation of MgAl-papain-LDH was confirmed by elemental analysis and transmission electron microscopy (TEM). Under SEM, MgAl-papain-LDH phases appear as nanothin platelets which are intergrown to flower-like aggregates. Steric size and activity of the enzyme was retained after deintercalation from MgAl-LDH framework, as was evidenced by light scattering and UV/vis measurements. Thus, papain is not denatured during intercalation, and LDH is a suitable host structure which can provide a time-controlled release of the biomolecule.

  5. Alkaline-earth metal phenylphosphonates and their intercalation chemistry

    Czech Academy of Sciences Publication Activity Database

    Melánová, Klára; Beneš, L.; Svoboda, J.; Zima, Vítězslav; Pospíšil, M.; Kovář, P.

    2018-01-01

    Roč. 47, č. 9 (2018), s. 2867-2880 ISSN 1477-9226 R&D Projects: GA ČR(CZ) GA17-10639S Institutional support: RVO:61389013 Keywords : intercalation * layered compounds * alkaline-earth metal phenylphosphonates Subject RIV: CA - Inorganic Chemistry OBOR OECD: Inorganic and nuclear chemistry Impact factor: 4.029, year: 2016

  6. Polypyrrole–titanium(IV) doped iron(III) oxide nanocomposites: Synthesis, characterization with tunable electrical and electrochemical properties

    International Nuclear Information System (INIS)

    Nandi, Debabrata; Ghosh, Arup Kumar; Gupta, Kaushik; De, Amitabha; Sen, Pintu; Duttachowdhury, Ankan; Ghosh, Uday Chand

    2012-01-01

    Highlights: ► Synthesis and characterization of polymer nanocomposite based on titanium doped iron(III) oxide. ► Electrical conductivity increased 100 times in composite with respect to polymer. ► Electrochemical capacitance of polymer composites increased with nanooxide content. ► Thermal stability of the polymer enhanced with nano oxide content. -- Abstract: Titanium(IV)-doped synthetic nanostructured iron(III) oxide (NITO) and polypyrrole (PPy) nanocomposites was fabricated by in situ polymerization using FeCl 3 as initiator. The polymer nanocomposites (PNCs) and pure NITO were characterized by X-ray diffraction, Föurier transform infrared spectroscopy, scanning electron microscopy, electron dispersive X-ray spectroscopy, transmission electron microscopy, etc. Thermo gravimetric and differential thermal analyses showed the enhancement of thermal stability of PNCs than the pure polymer. Electrical conductivity of the PNCs had increased significantly from 0.793 × 10 −2 S/cm to 0.450 S/cm with respect to the PPy, and that had been explained by 3-dimensional variable range hopping (VRH) conduction mechanisms. In addition, the specific capacitance of PNCs had increased from 147 F/g to 176 F/g with increasing NITO content than that of pure NITO (26 F/g), presumably due to the growing of mesoporous structure with increasing NITO content in PNCs which reduced the charge transfer resistance significantly.

  7. Reverse osmosis membrane composition, structure and performance modification by bisulphite, iron(III), bromide and chlorite exposure.

    Science.gov (United States)

    Ferrer, O; Gibert, O; Cortina, J L

    2016-10-15

    Reverse osmosis (RO) membrane exposure to bisulphite, chlorite, bromide and iron(III) was assessed in terms of membrane composition, structure and performance. Membrane composition was determined by Rutherford backscattering spectrometry (RBS) and membrane performance was assessed by water and chloride permeation, using a modified version of the solution-diffusion model. Iron(III) dosage in presence of bisulphite led to an autooxidation of the latter, probably generating free radicals which damaged the membrane. It comprised a significant raise in chloride passage (chloride permeation coefficient increased 5.3-5.1 fold compared to the virgin membrane under the conditions studied) rapidly. No major differences in terms of water permeability and membrane composition were observed. Nevertheless, an increase in the size of the network pores, and a raise in the fraction of aggregate pores of the polyamide (PA) layer were identified, but no amide bond cleavage was observed. These structural changes were therefore, in accordance with the transport properties observed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Adsorption and transformation of selected human-used macrolide antibacterial agents with iron(III) and manganese(IV) oxides

    Energy Technology Data Exchange (ETDEWEB)

    Feitosa-Felizzola, Juliana [Laboratoire Chimie Provence, Aix-Marseille Universites-CNRS (UMR 6264), 3 place Victor Hugo, 13331 Marseille Cedex 3 (France); Hanna, Khalil [Laboratoire de Chimie Physique et Microbiologie pour l' Environnement, CNRS-Universite Henri Poincare-Nancy 1 (UMR 7564), 405 rue de Vandoeuvre, 54600 Villers-les-Nancy (France); Chiron, Serge [Laboratoire Chimie Provence, Aix-Marseille Universites-CNRS (UMR 6264), 3 place Victor Hugo, 13331 Marseille Cedex 3 (France)], E-mail: serge.chiron@univ-provence.fr

    2009-04-15

    The adsorption/transformation of two members (clarithromycin and roxithromycin) of the macrolide (ML) antibacterial agents on the surface of three environmental subsurface sorbents (clay, iron(III) and manganese(IV) oxy-hydroxides) was investigated. The adsorption fitted well to the Freundlich model with a high sorption capacity. Adsorption probably occurred through a surface complexation mechanism and was accompanied by slow degradation of the selected MLs. Transformation proceeded through two parallel pathways: a major pathway was the hydrolysis of the cladinose sugar, and to a lesser extent the hydrolysis of the lactone ring. A minor pathway was the N-dealkylation of the amino sugar. This study indicates that Fe(III) and Mn(IV) oxy-hydroxides in aquatic sediments may play an important role in the natural attenuation of MLs. Such an attenuation route yields a range of intermediates that might retain some of their biological activity. - Iron(III) and manganese(IV) oxy-hydroxides in aquatic sediments may play an important role in the natural attenuation of macrolide antibacterial agents.

  9. Adsorption and transformation of selected human-used macrolide antibacterial agents with iron(III) and manganese(IV) oxides

    International Nuclear Information System (INIS)

    Feitosa-Felizzola, Juliana; Hanna, Khalil; Chiron, Serge

    2009-01-01

    The adsorption/transformation of two members (clarithromycin and roxithromycin) of the macrolide (ML) antibacterial agents on the surface of three environmental subsurface sorbents (clay, iron(III) and manganese(IV) oxy-hydroxides) was investigated. The adsorption fitted well to the Freundlich model with a high sorption capacity. Adsorption probably occurred through a surface complexation mechanism and was accompanied by slow degradation of the selected MLs. Transformation proceeded through two parallel pathways: a major pathway was the hydrolysis of the cladinose sugar, and to a lesser extent the hydrolysis of the lactone ring. A minor pathway was the N-dealkylation of the amino sugar. This study indicates that Fe(III) and Mn(IV) oxy-hydroxides in aquatic sediments may play an important role in the natural attenuation of MLs. Such an attenuation route yields a range of intermediates that might retain some of their biological activity. - Iron(III) and manganese(IV) oxy-hydroxides in aquatic sediments may play an important role in the natural attenuation of macrolide antibacterial agents

  10. Nuclear fuel technology - Determination of uranium in solutions, uranium hexafluoride and solids - Part 2: Iron(II) reduction/cerium(IV) oxidation titrimetric method

    International Nuclear Information System (INIS)

    2004-01-01

    This first edition of ISO 7097-1 together with ISO 7097-2:2004 cancels and replaces ISO 7097:1983, which has been technically revised, and ISO 9989:1996. ISO 7097 consists of the following parts, under the general title Nuclear fuel technology - Determination of uranium in solutions, uranium hexafluoride and solids: Part 1: Iron(II) reduction/potassium dichromate oxidation titrimetric method; Part 2: Iron(II) reduction/cerium(IV) oxidation titrimetric method. This part 2. of ISO 7097 describes procedures for determination of uranium in solutions, uranium hexafluoride and solids. The procedures described in the two independent parts of this International Standard are similar: this part uses a titration with cerium(IV) and ISO 7097-1 uses a titration with potassium dichromate

  11. Nuclear fuel technology - Determination of uranium in solutions, uranium hexafluoride and solids - Part 1: Iron(II) reduction/potassium dichromate oxidation titrimetric method

    International Nuclear Information System (INIS)

    2004-01-01

    This first edition of ISO 7097-1 together with ISO 7097-2:2004 cancels and replaces ISO 7097:1983, which has been technically revised, and ISO 9989:1996. ISO 7097 consists of the following parts, under the general title Nuclear fuel technology - Determination of uranium in solutions, uranium hexafluoride and solids: Part 1: Iron(II) reduction/potassium dichromate oxidation titrimetric method; Part 2: Iron(II) reduction/cerium(IV) oxidation titrimetric method. This part 1. of ISO 7097 describes procedures for the determination of uranium in solutions, uranium hexafluoride and solids. The procedures described in the two independent parts of this International Standard are similar: this part uses a titration with potassium dichromate and ISO 7097-2 uses a titration with cerium(IV)

  12. The Effect of Temperature and Ionic Strength on the Oxidation of Iodide by Iron(III): A Clock Reaction Kinetic Study

    Science.gov (United States)

    Bauer, Jurica; Tomisic, Vladislav; Vrkljan, Petar B. A.

    2012-01-01

    A laboratory exercise has recently been reported in which the students use the initial rates method based on the clock reaction approach to deduce the rate law and propose a reaction mechanism for the oxidation of iodide by iron(III) ions. The same approach is used in the exercise proposed herein; the students determine the dependence of the…

  13. Mononuclear nonheme iron(III) complexes that show superoxide dismutase-like activity and antioxidant effects against menadione-mediated oxidative stress.

    Science.gov (United States)

    Hitomi, Yutaka; Iwamoto, Yuji; Kashida, Akihiro; Kodera, Masahito

    2015-05-21

    This communication describes the superoxide dismutase (SOD)-like activity of mononuclear iron(III) complexes with pentadentate monocarboxylamido ligands. The SOD activity can be controlled by the electronic nature of the substituent group on the ligand. The nitro-substituted complex showed clear cytoprotective activity against menadione-mediated oxidative stress in cultured cells.

  14. Strontium Metylphosphonate Trihydrate: An Example of a New Class of Host Materials for Intercalation Reactions - Synthesis, Structure and Intercalation Behavior

    Czech Academy of Sciences Publication Activity Database

    Beneš, L.; Melánová, Klára; Svoboda, Jan; Zima, Vítězslav; Růžička, A.; Trchová, Miroslava

    2011-01-01

    Roč. 6, leden (2011), s. 850-859 ISSN 1434-1948 R&D Projects: GA ČR GA203/08/0208 Institutional research plan: CEZ:AV0Z40500505 Keywords : layered compounds * intercalates * solid-state structures Subject RIV: CA - Inorganic Chemistry Impact factor: 3.049, year: 2011

  15. Intercalation of organic molecules into SnS{sub 2} single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Toh, M.L.; Tan, K.J.; Wei, F.X.; Zhang, K.K.; Jiang, H. [School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Ave., Singapore 639798 (Singapore); Kloc, C., E-mail: ckloc@ntu.edu.sg [School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Ave., Singapore 639798 (Singapore)

    2013-02-15

    SnS{sub 2} is a layered semiconductor with a van der Waals gap separating the covalently bonded layers. In this study, post-synthesis intercalation of donor organic amine molecules, such as ethylenediamine (en), into tin disulfide and secondary intercalation of p-phenylenediamine (PPD) and 1, 5-naphthalenediamine (NDA) into SnS{sub 2e}n have been verified with X-ray diffraction. PPD and NDA did not intercalate directly even during prolonged annealing but replaced en readily if en was already present in the van der Waals gap. The c-lattice dilation is proportional to the intercalant size. Unit cell lattices of intercalated products were determined from the positions of the X-ray diffraction peaks. Optical images taken during the intercalation showed that intercalation progressed from the periphery towards the interior of the crystal. TEM diffraction patterns in the [0 0 1] direction of SnS{sub 2} after intercalation revealed defects and stacking mismatches among the SnS{sub 2} layers caused by the intercalation. UV-Vis absorption studies showed a red shift in the band edge of the SnS{sub 2} material after intercalation. The band edge was 2.2 eV for pristine SnS{sub 2}; after intercalation with en or PPD, the absorbance spectra band edges shifted to approximately 0.7 eV or 0.5 eV, respectively. - Graphical Abstract: SnS{sub 2} single crystals were intercalated with organic amine molecules such as ethylenediamine, phenylenediamine and naphthalenediamine. Absorption studies showed red shift of band edge after intercalation, which was consistent with optical observations. X-ray diffraction indicated lattice dilation in the c-lattice of SnS{sub 2} after intercalation. Highlights: Black-Right-Pointing-Pointer Organic molecules intercalated inhomogenously between covalently bonded SnS{sub 2} layers. Black-Right-Pointing-Pointer Ethylenediamine (en) intercalate directly into SnS{sub 2}. Black-Right-Pointing-Pointer Phenylenediamine (PPD) and naphthalenediamine (NDA) can be

  16. Intercalation of organic molecules into SnS2 single crystals

    International Nuclear Information System (INIS)

    Toh, M.L.; Tan, K.J.; Wei, F.X.; Zhang, K.K.; Jiang, H.; Kloc, C.

    2013-01-01

    SnS 2 is a layered semiconductor with a van der Waals gap separating the covalently bonded layers. In this study, post-synthesis intercalation of donor organic amine molecules, such as ethylenediamine (en), into tin disulfide and secondary intercalation of p-phenylenediamine (PPD) and 1, 5-naphthalenediamine (NDA) into SnS 2e n have been verified with X-ray diffraction. PPD and NDA did not intercalate directly even during prolonged annealing but replaced en readily if en was already present in the van der Waals gap. The c-lattice dilation is proportional to the intercalant size. Unit cell lattices of intercalated products were determined from the positions of the X-ray diffraction peaks. Optical images taken during the intercalation showed that intercalation progressed from the periphery towards the interior of the crystal. TEM diffraction patterns in the [0 0 1] direction of SnS 2 after intercalation revealed defects and stacking mismatches among the SnS 2 layers caused by the intercalation. UV–Vis absorption studies showed a red shift in the band edge of the SnS 2 material after intercalation. The band edge was 2.2 eV for pristine SnS 2 ; after intercalation with en or PPD, the absorbance spectra band edges shifted to approximately 0.7 eV or 0.5 eV, respectively. - Graphical Abstract: SnS 2 single crystals were intercalated with organic amine molecules such as ethylenediamine, phenylenediamine and naphthalenediamine. Absorption studies showed red shift of band edge after intercalation, which was consistent with optical observations. X-ray diffraction indicated lattice dilation in the c-lattice of SnS 2 after intercalation. Highlights: ► Organic molecules intercalated inhomogenously between covalently bonded SnS 2 layers. ► Ethylenediamine (en) intercalate directly into SnS 2 . ► Phenylenediamine (PPD) and naphthalenediamine (NDA) can be intercalated into SnS 2 secondary. ► In a secondary intercalation the bonds between layers are weakened by direct

  17. High-Density Chemical Intercalation of Zero-Valent Copper into Bi 2 Se 3 Nanoribbons

    KAUST Repository

    Koski, Kristie J.; Cha, Judy J.; Reed, Bryan W.; Wessells, Colin D.; Kong, Desheng; Cui, Yi

    2012-01-01

    A major goal of intercalation chemistry is to intercalate high densities of guest species without disrupting the host lattice. Many intercalant concentrations, however, are limited by the charge of the guest species. Here we have developed a general solution-based chemical method for intercalating extraordinarily high densities of zero-valent copper metal into layered Bi 2Se 3 nanoribbons. Up to 60 atom % copper (Cu 7.5Bi 2Se 3) can be intercalated with no disruption to the host lattice using a solution disproportionation redox reaction. © 2012 American Chemical Society.

  18. High-Density Chemical Intercalation of Zero-Valent Copper into Bi 2 Se 3 Nanoribbons

    KAUST Repository

    Koski, Kristie J.

    2012-05-09

    A major goal of intercalation chemistry is to intercalate high densities of guest species without disrupting the host lattice. Many intercalant concentrations, however, are limited by the charge of the guest species. Here we have developed a general solution-based chemical method for intercalating extraordinarily high densities of zero-valent copper metal into layered Bi 2Se 3 nanoribbons. Up to 60 atom % copper (Cu 7.5Bi 2Se 3) can be intercalated with no disruption to the host lattice using a solution disproportionation redox reaction. © 2012 American Chemical Society.

  19. Tuning the electronic structure of graphene through alkali metal and halogen atom intercalation

    Science.gov (United States)

    Ahmad, Sohail; Miró, Pere; Audiffred, Martha; Heine, Thomas

    2018-04-01

    The deposition, intercalation and co-intercalation of heavy alkali metals and light halogens atoms in graphene mono- and bilayers have been studied using first principles density-functional calculations. Both the deposition and the intercalation of alkali metals gives rise to n-type doping due to the formation of M+-C- pairs. The co-intercalation of a 1:1 ratio of alkali metals and halogens derives into the formation of ionic pairs among the intercalated species, unaltering the electronic structure of the layered material.

  20. A Stopped-Flow Kinetics Experiment for Advanced Undergraduate Laboratories: Formation of Iron(III) Thiocyannate

    Science.gov (United States)

    Clark, Charles R.

    1997-10-01

    A series of 15 stopped-flow kinetic experiments relating to the formation of iron(III)- thiocyanate at 25.0 °C and I = 1.0 M (NaClO4) is described. A methodology is given whereby solution preparation and data collection are able to be carried out within the time scale of a single laboratory period (3-4 h). Kinetic data are obtained using constant [SCN-], and at three H+ concentrations (0.10, 0.20, 0.30 M) for varying concentrations of Fe3+ (ca. 0.0025 - 0.020 M). Rate data (450 nm) are consistent with rate laws for the forward and reverse reactions: kf = (k1 + k2Ka1/[H+])[Fe3+] and kr = k-1 + k-2Ka2/[H+] respectively, with k1,k-1 corresponding to the rate constants for formation and decay of FeSCN2+, k2, k-2 to the rate constants for formation and decay of the FeSCN(OH)+ ion and Ka1,Ka2 to the acid dissociation constants (coordinated OH2 ionization) of Fe3+ and FeSCN2+. Using literature values for the latter two quantities ( Ka1 = 2.04 x 10-3 M, Ka2 = 6.5 x 10-5 M) allows values for the four rate constants to be obtained. A typical data set is analyzed to give k1 = 109(10) M-1s-1, k-1 = 0.79(0.10) s-1, k2= 8020(800) M-1s-1, k-2 = 2630(230) s-1. Absorbance change data for reaction (DeltaA) follow the expression: DeltaA = Alim.Kf.[Fe3+]/(1 + Kf.[Fe3+]), with Alim corresponding to the absorbance of fully formed FeSCN2+ (i.e. free SCN- absent) and Kf to the formation constant of this complex (value in the example 112(5) M-1, c.f. 138(29) M-1 from the kinetic data).

  1. Formation of intercalation compound of kaolinite-glycine via displacing guest water by glycine.

    Science.gov (United States)

    Zheng, Wan; Zhou, Jing; Zhang, Zhenqian; Chen, Likun; Zhang, Zhongfei; Li, Yong; Ma, Ning; Du, Piyi

    2014-10-15

    The kaolinite-glycine intercalation compound was successfully formed by displacing intercalated guest water molecules in kaolinite hydrate as a precursor. The microstructure of the compound was characterized by X-ray diffraction, Fourier Transform Infrared Spectroscopy and Scanning Electron Microscope. Results show that glycine can only be intercalated into hydrated kaolinite to form glycine-kaolinite by utilizing water molecules as a transition phase. The intercalated glycine molecules were squeezed partially into the ditrigonal holes in the silicate layer, resulting in the interlayer distance of kaolinite reaching 1.03nm. The proper intercalation temperature range was between 20°C and 80°C. An intercalation time of 24h or above was necessary to ensure the complete formation of kaolinite-glycine. The highest intercalation degree of about 84% appeared when the system was reacted at the temperature of 80°C for 48h. There were two activation energies for the intercalation of glycine into kaolinite, one being 21kJ/mol within the temperature range of 20-65°C and the other 5.8kJ/mol between 65°C and 80°C. The intercalation degree (N) and intercalation velocity (v) of as a function of intercalation time (t) can be empirically expressed as N=-79.35e(-)(t)(/14.8)+80.1 and v=5.37e(-)(t)(/14.8), respectively. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Sodium-Ion Intercalated Transparent Conductors with Printed Reduced Graphene Oxide Networks.

    Science.gov (United States)

    Wan, Jiayu; Gu, Feng; Bao, Wenzhong; Dai, Jiaqi; Shen, Fei; Luo, Wei; Han, Xiaogang; Urban, Daniel; Hu, Liangbing

    2015-06-10

    In this work, we report for the first time that Na-ion intercalation of reduced graphene oxide (RGO) can significantly improve its printed network's performance as a transparent conductor. Unlike pristine graphene that inhibits Na-ion intercalation, the larger layer-layer distance of RGO allows Na-ion intercalation, leading to simultaneously much higher DC conductivity and higher optical transmittance. The typical increase of transmittance from 36% to 79% and decrease of sheet resistance from 83k to 311 Ohms/sq in the printed network was observed after Na-ion intercalation. Compared with Li-intercalated graphene, Na-ion intercalated RGO shows much better environmental stability, which is likely due to the self-terminating oxidation of Na ions on the RGO edges. This study demonstrated the great potential of metal-ion intercalation to improve the performance of printed RGO network for transparent conductor applications.

  3. Nuclear Magnetic Resonance Study of Fluorine-Graphite Intercalation Compounds

    International Nuclear Information System (INIS)

    Panich, A.M.; Goren, S.D.; Nakajima, T.; Vieth, H.-M.; Privalov, A.

    1998-01-01

    To study the origin of semimetal-metal and metal-insulator transformations, localization effects and C-E bonding in fluorine-intercalated graphite C x F, 13 C and 19 F NMR investigations have been carried out for a wide range of fluorine content, 3.8 8, are attributed to mobile fluorine acceptor species which are responsible for the increase of electric conductivity in the dilute compound. When increasing the fluorine content to x ∼ 8 corresponding to the maximum electric conductivity, covalent C-P bonds start to oc- cur. The number of these bonds grows with fluorine content resulting in the decrease in conductivity which is caused by a percolation mechanism rather than by a change in bond length. A difference in 19 F chemical shift for fluorine-intercalated graphite C x F and covalent graphite fluoride (CF) n has been observed and is attributed to different C-P bonding in these compounds

  4. Induced magnetism in transition metal intercalated graphitic systems

    KAUST Repository

    Kaloni, Thaneshwor P.

    2011-10-26

    We investigate the structure, chemical bonding, electronic properties, and magnetic behavior of a three-dimensional graphitic network in aba and aaa stacking with intercalated transition metal atoms (Mn, Fe, Co, Ni, and Cu). Using density functional theory, we find induced spin-polarization of the C atoms both when the graphene sheets are aba stacked (forming graphite) and aaa stacked (resembling bi-layer graphene). The magnetic moment induced by Mn, Fe, and Co turns out to vary from 1.38 μB to 4.10 μB, whereas intercalation of Ni and Cu does not lead to a magnetic state. The selective induction of spin-polarization can be utilized in spintronic and nanoelectronic applications.

  5. Induced magnetism in transition metal intercalated graphitic systems

    KAUST Repository

    Kaloni, Thaneshwor P.; Schwingenschlö gl, Udo; Upadhyay Kahaly, M.

    2011-01-01

    We investigate the structure, chemical bonding, electronic properties, and magnetic behavior of a three-dimensional graphitic network in aba and aaa stacking with intercalated transition metal atoms (Mn, Fe, Co, Ni, and Cu). Using density functional theory, we find induced spin-polarization of the C atoms both when the graphene sheets are aba stacked (forming graphite) and aaa stacked (resembling bi-layer graphene). The magnetic moment induced by Mn, Fe, and Co turns out to vary from 1.38 μB to 4.10 μB, whereas intercalation of Ni and Cu does not lead to a magnetic state. The selective induction of spin-polarization can be utilized in spintronic and nanoelectronic applications.

  6. Fabrication of graphene device from graphite intercalation compound

    Science.gov (United States)

    Yagi, Ryuta; Kobara, Hiroaki; Shimomura, Midori; Tahara, Fumiya; Fukada, Seiya

    2012-02-01

    The mechanical exfoliation of graphite is possibly the simplest and practical method in laboratories to obtain graphene flakes for scientific research. However efficiency for obtaining graphene, with desired layer-number and size, depends largely on crystal specific characters, eg., dislocations. To improve the issue, we have adopted graphite intercalation compound (GIC) instead of graphite for a starting material. Generally, GIC is chemically active. We used SbCl5- GIC, which is stable in the atmosphere. Stage structure of SbCl5-GIC could be tuned by temperature of intercalation. We found that considerable number of undoped graphene flakes coexisted with thin SbCl5-GIC flakes, on a substrate where flakes were transferred.?Statistical inspection of number of graphene layer indicated that it is significantly dependent on the stage number of GIC.

  7. Production of polyol carbonates and their intercalation into Smectite clays

    OpenAIRE

    Shaheen, Uzma

    2017-01-01

    In hyper-saline conditions, clays in geosynthetic clay liners contract and fail to form a hydraulic barrier due to removal of water from the interlayer spaces of smectite, which is the swelling mineral component of bentonites used in geosynthetic clay liners. Five-membered cyclic carbonates such as propylene carbonate have been reported to form stable intercalated complexes with hydrated Na-smectite, which maintain swollen states at 1M). Glycerol carbonate was selected as an alternative c...

  8. Intercalation compounds of vanadium(5) phosphates with glycerol

    International Nuclear Information System (INIS)

    Yakovleva, T.N.; Vykhodtseva, K.I.; Tarasova, D.V.; Soderzhinova, M.M.

    1997-01-01

    Interaction products of glycerol aqueous solutions with vanadium(5) phosphates were investigated by the methods of ESR, X-ray phase and thermal analyses. It is shown that glycerol molecules enter the interlayer space of VOPO 4 · 2H 2 O lattice with formation of disordered intercalated compounds with glycerol on the basis of partially reduced vanadium phosphate form when using α-VOPO 4 . 16 refs., 4 figs., 1 tab

  9. Molecular Intercalation and Cohesion of Organic Bulk Heterojunction Photovoltaic Devices

    KAUST Repository

    Bruner, Christopher; Miller, Nichole C.; McGehee, Michael D.; Dauskardt, Reinhold H.

    2013-01-01

    The phase separated bulk heterojunction (BHJ) layer in BHJ polymer:fullerene organic photovoltaic devices (OPV) are mechanically weak with low values of cohesion. Improved cohesion is important for OPV device thermomechanical reliability. BHJ devices are investigated and how fullerene intercalation within the active layer affects cohesive properties in the BHJ is shown. The intercalation of fullerenes between the side chains of the polymers poly(3,3″′-didocecyl quaterthiophene) (PQT-12) and poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene (pBTTT) is shown to enhance BHJ layer cohesion. Cohesion values range from ≈1 to 5 J m -2, depending on the polymer:fullerene blend, processing conditions, and composition. Devices with non-intercalated BHJ layers are found to have significantly reduced values of cohesion. The resulting device power conversion efficiencies (PCE) are also investigated and correlated with the device cohesion. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Molecular Intercalation and Cohesion of Organic Bulk Heterojunction Photovoltaic Devices

    KAUST Repository

    Bruner, Christopher

    2013-01-17

    The phase separated bulk heterojunction (BHJ) layer in BHJ polymer:fullerene organic photovoltaic devices (OPV) are mechanically weak with low values of cohesion. Improved cohesion is important for OPV device thermomechanical reliability. BHJ devices are investigated and how fullerene intercalation within the active layer affects cohesive properties in the BHJ is shown. The intercalation of fullerenes between the side chains of the polymers poly(3,3″′-didocecyl quaterthiophene) (PQT-12) and poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene (pBTTT) is shown to enhance BHJ layer cohesion. Cohesion values range from ≈1 to 5 J m -2, depending on the polymer:fullerene blend, processing conditions, and composition. Devices with non-intercalated BHJ layers are found to have significantly reduced values of cohesion. The resulting device power conversion efficiencies (PCE) are also investigated and correlated with the device cohesion. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Selective and low temperature transition metal intercalation in layered tellurides

    Science.gov (United States)

    Yajima, Takeshi; Koshiko, Masaki; Zhang, Yaoqing; Oguchi, Tamio; Yu, Wen; Kato, Daichi; Kobayashi, Yoji; Orikasa, Yuki; Yamamoto, Takafumi; Uchimoto, Yoshiharu; Green, Mark A.; Kageyama, Hiroshi

    2016-01-01

    Layered materials embrace rich intercalation reactions to accommodate high concentrations of foreign species within their structures, and find many applications spanning from energy storage, ion exchange to secondary batteries. Light alkali metals are generally most easily intercalated due to their light mass, high charge/volume ratio and in many cases strong reducing properties. An evolving area of materials chemistry, however, is to capture metals selectively, which is of technological and environmental significance but rather unexplored. Here we show that the layered telluride T2PTe2 (T=Ti, Zr) displays exclusive insertion of transition metals (for example, Cd, Zn) as opposed to alkali cations, with tetrahedral coordination preference to tellurium. Interestingly, the intercalation reactions proceed in solid state and at surprisingly low temperatures (for example, 80 °C for cadmium in Ti2PTe2). The current method of controlling selectivity provides opportunities in the search for new materials for various applications that used to be possible only in a liquid. PMID:27966540

  12. Crystal structures of superconducting sodium intercalates of hafnium nitride chloride

    International Nuclear Information System (INIS)

    Oro-Sole, J.; Frontera, C.; Beltran-Porter, D.; Lebedev, O.I.; Van Tendeloo, G.; Fuertes, A.

    2006-01-01

    Sodium intercalation compounds of HfNCl have been prepared at room temperature in naphtyl sodium solutions in tetrahydrofuran and their crystal structure has been investigated by Rietveld refinement using X-ray powder diffraction data and high-resolution electron microscopy. The structure of two intercalates with space group R3-bar m and lattice parameters a=3.58131(6)A, c=57.752(6)A, and a=3.58791(8)A, c=29.6785(17)A is reported, corresponding to the stages 2 and 1, respectively, of Na x HfNCl. For the stage 2 phase an ordered model is presented, showing two crystallographically independent [HfNCl] units with an alternation of the Hf-Hf interlayer distance along the c-axis, according with the occupation by sodium atoms of one out of two van der Waals gaps. Both stages 1 and 2 phases are superconducting with critical temperatures between 20 and 24K, they coexist in different samples with proportions depending on the synthesis conditions, and show a variation in c spacing that can be correlated with the sodium stoichiometry. High-resolution electron microscopy images of the host and intercalated samples show bending of the HfNCl bilayers as well as stacking faults in some regions, which coexist in the same crystal with ordered domains

  13. Economically attractive route for the preparation of high quality magnetic nanoparticles by the thermal decomposition of iron(III) acetylacetonate.

    Science.gov (United States)

    Effenberger, Fernando B; Couto, Ricardo A; Kiyohara, Pedro K; Machado, Giovanna; Masunaga, Sueli H; Jardim, Renato F; Rossi, Liane M

    2017-03-17

    The thermal decomposition (TD) methods are among the most successful in obtaining magnetic nanoparticles with a high degree of control of size and narrow particle size distribution. Here we investigated the TD of iron(III) acetylacetonate in the presence of oleic acid, oleylamine, and a series of alcohols in order to disclose their role and also investigate economically attractive alternatives for the synthesis of iron oxide nanoparticles without compromising their size and shape control. We have found that some affordable and reasonably less priced alcohols, such as 1,2-octanediol and cyclohexanol, may replace the commonly used and expensive 1,2-hexadecanediol, providing an economically attractive route for the synthesis of high quality magnetic nanoparticles. The relative cost for the preparation of Fe 3 O 4 NPs is reduced to only 21% and 9% of the original cost when using 1,2-octanediol and cyclohexanol, respectively.

  14. Lithium, rubidium and cesium ion removal using potassium iron(III) hexacyanoferrate(II) supported on polymethylmethacrylate

    International Nuclear Information System (INIS)

    Shabana Taj; Din Muhammad; Ashraf Chaudhry, M.; Muhammad Mazhar

    2011-01-01

    Potassium iron(III) hexacyanoferrate(II) supported on poly methyl methacrylate, has been developed and investigated for the removal of lithium, rubidium and cesium ions. The material is capable of sorbing maximum quantities of these ions from 5.0, 2.5 and 4.5 M HNO 3 solutions respectively. Sorption studies, conducted individually for each metal ion, under optimized conditions, demonstrated that it was predominantly physisorption in the case of lithium ion while shifting to chemisorption with increasing ionic size. Distribution coefficient (K d ) values followed the order Cs + > Rb + > Li + at low concentrations of metal ions. Following these findings Cs + can preferably be removed from 1.5 to 5 M HNO 3 nuclear waste solutions. (author)

  15. Ge-intercalated graphene: The origin of the p-type to n-type transition

    KAUST Repository

    Kaloni, Thaneshwor P.

    2012-09-01

    Recently huge interest has been focussed on Ge-intercalated graphene. In order to address the effect of Ge on the electronic structure, we study Ge-intercalated free-standing C 6 and C 8 bilayer graphene, bulk C 6Ge and C 8Ge, as well as Ge-intercalated graphene on a SiC(0001) substrate, by density functional theory. In the presence of SiC(0001), there are three ways to obtain n-type graphene: i) intercalation between C layers; ii) intercalation at the interface to the substrate in combination with Ge deposition on the surface; and iii) cluster intercalation. All other configurations under study result in p-type states irrespective of the Ge coverage. We explain the origin of the different doping states and establish the conditions under which a transition occurs. © Copyright EPLA, 2012.

  16. Cloud point extraction of iron(III) and vanadium(V) using 8-quinolinol derivatives and Triton X-100 and determination of 10(-7)moldm(-3) level iron(III) in riverine water reference by a graphite furnace atomic absorption spectroscopy.

    Science.gov (United States)

    Ohashi, Akira; Ito, Hiromi; Kanai, Chikako; Imura, Hisanori; Ohashi, Kousaburo

    2005-01-30

    The cloud point extraction behavior of iron(III) and vanadium(V) using 8-quinolinol derivatives (HA) such as 8-quinolinol (HQ), 2-methyl-8-quinolinol (HMQ), 5-butyloxymethyl-8-quinolinol (HO(4)Q), 5-hexyloxymethyl-8-quinolinol (HO(6)Q), and 2-methyl-5-octyloxymethyl-8-quinolinol (HMO(8)Q) and Triton X-100 solution was investigated. Iron(III) was extracted with HA and 4% (v/v) Triton X-100 in the pH range of 1.70-5.44. Above pH 4.0, more than 95% of iron(III) was extracted with HQ, HMQ, and HMO(8)Q. Vanadium(V) was also extracted with HA and 4% (v/v) Triton X-100 in the pH range of 2.07-5.00, and the extractability increased in the following order of HMQ HQ cloud point extraction was applied to the determination of iron(III) in the riverine water reference by a graphite furnace atomic absorption spectroscopy. When 1.25 x 10(-3)M HMQ and 1% (v/v) Triton X-100 were used, the found values showed a good agreement with the certified ones within the 2% of the R.S.D. Moreover, the effect of an alkyl group on the solubility of 5-alkyloxymethyl-8-quinolinol and 2-methyl-5-alkyloxymethyl-8-quinolinol in 4% (v/v) Triton X-100 at 25 degrees C was also investigated.

  17. Thermoelectric Properties of Li-Intercalated ZrSe2 Single Crystals

    DEFF Research Database (Denmark)

    Holgate, Tim; Liu, Yufei; Hitchcock, Dale

    2013-01-01

    Zirconium diselenide (ZrSe2) is one of many members of the layer-structured transition-metal dichalcogenide family. The structure of these materials features a weakly bonded van der Waals gap between covalently bonded CdI2-type atomic layers that may host a wide range of intercalants. Intercalation......, and low cost of such materials, merit further thermoelectric investigations of intercalated zirconium diselenide, especially in conjunction with a substitutional doping approach....

  18. Preparation and properties of Mg/Al layered double hydroxide-oleate and -stearate intercalation compounds

    International Nuclear Information System (INIS)

    Inomata, Kazuya; Ogawa, Makoto

    2006-01-01

    Mg/Al layered double hydroxide-oleate and -stearate intercalation compounds were successfully synthesized by the reconstruction method under hydrothermal conditions from calcined hydrotalcite. The intercalation compounds were characterized by the high structural regularity as evidenced by the sharp and intense X-ray diffraction peaks. The oleate intercalated layered double hydroxide exhibits unique physicochemical properties such as a reversible thermoresponsive change in the basal spacing and swelling in organic solvents such as n-alkanes. (author)

  19. Synthesis of graphite intercalation compound of group VI metals and uranium hexafluorides

    International Nuclear Information System (INIS)

    Fukui, Toshihiro; Hagiwara, Rika; Ema, Keiko; Ito, Yasuhiko

    1993-01-01

    Systematic investigations were made on the synthesis of graphite intercalation compounds of group VI transition metals (W and Mo) and uranium hexafluorides. The reactions were performed by interacting liquid or gaseous metal hexafluorides with or without elemental fluorine at ambient temperature. The degree of intercalation of these metal fluorides depends on the formation enthalpy of fluorometallate anion from the original metal hexafluoride, as has been found for other intercalation reactions of metal fluorides. (author)

  20. Adsorption of Phosphate Ion in Water with Lithium-Intercalated Gibbsite

    OpenAIRE

    Riwandi Sihombing; Yuni Krisyuningsih Krisnandi; Rahma Widya; Siti Zahrotul Luthfiyah; Rika Tri Yunarti

    2015-01-01

    In order to enhance adsorption capacity of gibbsite (Al(OH)3 as an adsorbent for the adsorption of phosphate in water, gibbsite was modified through lithium-intercalation. The purification method of Tributh and Lagaly was applied prior to intercalation. The Li-Intercalation was prepared by the dispersion of gibbsite into LiCl solution for 24 hours. This intercalation formed an cationic clay with the structure of [LiAl2(OH)6]+ and exchangeable Cl- anions in the gibbsite interlayer. A phosphate...

  1. Tuning the Properties of Polymer Bulk Heterojunction Solar Cells by Adjusting Fullerene Size to Control Intercalation

    KAUST Repository

    Cates, Nichole C.; Gysel, Roman; Beiley, Zach; Miller, Chad E.; Toney, Michael F.; Heeney, Martin; McCulloch, Iain; McGehee, Michael D.

    2009-01-01

    We demonstrate that intercalation of fullerene derivatives between the side chains of conjugated polymers can be controlled by adjusting the fullerene size and compare the properties of intercalated and nonintercalated poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene (pBTTT):fullerene blends. The intercalated blends, which exhibit optimal solar-cell performance at 1:4 polymer:fullerene by weight, have better photoluminescence quenching and lower absorption than the nonintercalated blends, which optimize at 1:1. Understanding how intercalation affects performance will enable more effective design of polymer:fullerene solar cells. © 2009 American Chemical Society.

  2. Structure and thermal decomposition of sulfated β-cyclodextrin intercalated in a layered double hydroxide

    International Nuclear Information System (INIS)

    Wang Ji; Wei Min; Rao Guoying; Evans, D.G.; Duan Xue

    2004-01-01

    The sodium salt of hexasulfated β-cyclodextrin has been synthesized and intercalated into a magnesium-aluminum layered double hydroxide by ion exchange. The structure, composition and thermal decomposition behavior of the intercalated material have been studied by variable temperature X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), inductively coupled plasma emission spectroscopy (ICP), and thermal analysis (TG-DTA) and a model for the structure has been proposed. The thermal stability of the intercalated sulfated β-cyclodextrin is significantly enhanced compared with the pure form before intercalation

  3. Structure and thermal decomposition of sulfated β-cyclodextrin intercalated in a layered double hydroxide

    Science.gov (United States)

    Wang, Ji; Wei, Min; Rao, Guoying; Evans, David G.; Duan, Xue

    2004-01-01

    The sodium salt of hexasulfated β-cyclodextrin has been synthesized and intercalated into a magnesium-aluminum layered double hydroxide by ion exchange. The structure, composition and thermal decomposition behavior of the intercalated material have been studied by variable temperature X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), inductively coupled plasma emission spectroscopy (ICP), and thermal analysis (TG-DTA) and a model for the structure has been proposed. The thermal stability of the intercalated sulfated β-cyclodextrin is significantly enhanced compared with the pure form before intercalation.

  4. Tuning the Properties of Polymer Bulk Heterojunction Solar Cells by Adjusting Fullerene Size to Control Intercalation

    KAUST Repository

    Cates, Nichole C.

    2009-12-09

    We demonstrate that intercalation of fullerene derivatives between the side chains of conjugated polymers can be controlled by adjusting the fullerene size and compare the properties of intercalated and nonintercalated poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene (pBTTT):fullerene blends. The intercalated blends, which exhibit optimal solar-cell performance at 1:4 polymer:fullerene by weight, have better photoluminescence quenching and lower absorption than the nonintercalated blends, which optimize at 1:1. Understanding how intercalation affects performance will enable more effective design of polymer:fullerene solar cells. © 2009 American Chemical Society.

  5. Structural effects on the electronic characteristics of intramolecularly intercalated alkali-rubrene complexes

    Energy Technology Data Exchange (ETDEWEB)

    Li, Tsung-Lung, E-mail: quantum@mail.ncyu.edu.tw [Department of Electrophysics, National Chia-Yi University, 300 Hsueh-Fu Road, Chiayi, 60004, Taiwan, ROC (China); Lu, Wen-Cai, E-mail: wencailu@jlu.edu.cn [Laboratory of Fiber Materials and Modern Textile, Growing Base for State Key Laboratory, College of Physics, Qingdao University, Qingdao, Shandong 266071 (China); State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun, Jilin 130021 (China)

    2016-11-01

    The geometric and electronic structures of neutral monolithium- and monosodium-rubrene (Li{sub 1} Rub and Na{sub 1} Rub) isomers are investigated and compared with monopotassium-rubrene (K{sub 1} Rub). Based on the alkali binding site, all isomers of these alkali-rubrene complexes can be subdivided into two types: intramolecularly intercalated and extramolecularly adsorbed. The minimum-energy Li{sub 1} Rub and Na{sub 1} Rub are intercalated structures, whereas the minimum-energy K{sub 1} Rub is adsorbed. The fact that the intercalated Li{sub 1} Rub and Na{sub 1} Rub structures are energetically favorable over the adsorbed ones can be explained by two energy rules. First, “double” proximity of the intercalating alkali element to a pair of phenyl side groups enormously reduces the total energy. Second, accommodation of a minuscule intercalant does not significantly deform the carbon frame and, thus, increases the energy only by a small amount. Additionally, the peculiar effects of intramolecular intercalation on the electronic structures of molecules are also studied in this simulation of monoalkali intercalation. In the monoalkali-intercalated rubrene complex, only one of the two pairs of phenyl groups of rubrene is intercalated, intentionally leaving another pair pristine, which facilitates the comparison of electronic structures between the intercalated and pristine pairs of phenyl side groups in a single molecule. The uniformity of chemical environments of the phenyl groups of the intercalated Li{sub 1} Rub/Na{sub 1} Rub is deteriorated by the incorporation of the intercalant, and leads to their spectral characteristics in contrast to K{sub 1} Rub. In particular, the introduction of the intercalant promotes the carbon 2p orbitals of the intercalated phenyl pair to take part in the electronic structures of the HOMO and LUMO peaks of Li{sub 1} Rub/Na{sub 1} Rub. The unpaired electron in the HOMO is delocalized over the backbone with higher probability of

  6. Physical and chemical studies of superconduction properties of the intercalation compounds

    International Nuclear Information System (INIS)

    Eder, F.X.; Lerf, A.

    1980-01-01

    The superconducting properties of the intercalation compounds of layered dichalcogenides were studied. Our studies were concerned mainly to the alkali metal intercalation derivatives of TaS 2 and NbS 2 , and later on extended to the molecule intercalation compounds. The main difficulties with this class of superconductors result from varying material properties; these are therefore the subject of broad intensity in our investigations. The results received on the physical and chemical properties of the intercalation compounds is utilized for a phenomenological description of the factors mainly determining there superconducting properties. (orig.) [de

  7. Mechanism of Si intercalation in defective graphene on SiC

    KAUST Repository

    Kaloni, Thaneshwor P.

    2012-10-01

    Previously reported experimental findings on Si-intercalated graphene on SiC(0001) seem to indicate the possibility of an intercalation process based on the migration of the intercalant through atomic defects in the graphene sheet. We employ density functional theory to show that such a process is in fact feasible and obtain insight into its details. By means of total energy and nudged elastic band calculations we are able to establish the mechanism on an atomic level and to determine the driving forces involved in the different steps of the intercalation process through atomic defects.

  8. Structural effects on the electronic characteristics of intramolecularly intercalated alkali-rubrene complexes

    International Nuclear Information System (INIS)

    Li, Tsung-Lung; Lu, Wen-Cai

    2016-01-01

    The geometric and electronic structures of neutral monolithium- and monosodium-rubrene (Li 1 Rub and Na 1 Rub) isomers are investigated and compared with monopotassium-rubrene (K 1 Rub). Based on the alkali binding site, all isomers of these alkali-rubrene complexes can be subdivided into two types: intramolecularly intercalated and extramolecularly adsorbed. The minimum-energy Li 1 Rub and Na 1 Rub are intercalated structures, whereas the minimum-energy K 1 Rub is adsorbed. The fact that the intercalated Li 1 Rub and Na 1 Rub structures are energetically favorable over the adsorbed ones can be explained by two energy rules. First, “double” proximity of the intercalating alkali element to a pair of phenyl side groups enormously reduces the total energy. Second, accommodation of a minuscule intercalant does not significantly deform the carbon frame and, thus, increases the energy only by a small amount. Additionally, the peculiar effects of intramolecular intercalation on the electronic structures of molecules are also studied in this simulation of monoalkali intercalation. In the monoalkali-intercalated rubrene complex, only one of the two pairs of phenyl groups of rubrene is intercalated, intentionally leaving another pair pristine, which facilitates the comparison of electronic structures between the intercalated and pristine pairs of phenyl side groups in a single molecule. The uniformity of chemical environments of the phenyl groups of the intercalated Li 1 Rub/Na 1 Rub is deteriorated by the incorporation of the intercalant, and leads to their spectral characteristics in contrast to K 1 Rub. In particular, the introduction of the intercalant promotes the carbon 2p orbitals of the intercalated phenyl pair to take part in the electronic structures of the HOMO and LUMO peaks of Li 1 Rub/Na 1 Rub. The unpaired electron in the HOMO is delocalized over the backbone with higher probability of distributing over the central two fused rings than over the outer two

  9. Potentiometric and electrokinetic signatures of iron(II) interactions with (α,γ)-Fe2O3.

    Science.gov (United States)

    Toczydłowska, Diana; Kędra-Królik, Karolina; Nejbert, Krzysztof; Preočanin, Tajana; Rosso, Kevin M; Zarzycki, Piotr

    2015-10-21

    The electrochemical signatures of Fe(II) interactions with iron(III) oxides are poorly understood, despite their importance in controlling the amount of mobilized iron. Here, we report the potentiometric titration of α,γ-Fe2O3 oxides exposed to Fe(II) ions. We monitored in situ surface and ζ potentials, the ratio of mobilized ferric to ferrous, and the periodically analyzed nanoparticle crystal structure using X-ray diffraction. Electrokinetic potential reveals weak but still noticeable specific sorption of Fe(II) to the oxide surface under acidic conditions, and pronounced adsorption under alkaline conditions that results in a surface potential reversal. By monitoring the aqueous iron(II/III) fraction, we found that the addition of Fe(II) ions produces platinum electrode response consistent with the iron solubility-activity curve. Although, XRD analysis showed no evidence of γ-Fe2O3 transformations along the titration pathway despite iron cycling between aqueous and solid reservoirs, the magnetite formation cannot be ruled out.

  10. The first iron(III) complexes with cyclin-dependent kinase inhibitors: Magnetic, spectroscopic (IR, ES+ MS, NMR, Fe-57 Mossbauer), theoretical, and biological activity studies

    Czech Academy of Sciences Publication Activity Database

    Trávníček, Zdeněk; Popa, Igor; Čajan, Michal; Zbořil, R.; Kryštof, Vladimír; Mikulík, J.

    2010-01-01

    Roč. 104, č. 4 (2010), s. 405-417 ISSN 0162-0134 R&D Projects: GA MŠk 1M0512; GA ČR GA301/08/1649 Institutional research plan: CEZ:AV0Z50380511 Keywords : Iron(III) complexes * 57Fe Mössbauer spectroscopy * CDK inhibition Subject RIV: CA - Inorganic Chemistry Impact factor: 3.317, year: 2010

  11. Intercalation of Si between MoS2 layers

    Directory of Open Access Journals (Sweden)

    Rik van Bremen

    2017-09-01

    Full Text Available We report a combined experimental and theoretical study of the growth of sub-monolayer amounts of silicon (Si on molybdenum disulfide (MoS2. At room temperature and low deposition rates we have found compelling evidence that the deposited Si atoms intercalate between the MoS2 layers. Our evidence relies on several experimental observations: (1 Upon the deposition of Si on pristine MoS2 the morphology of the surface transforms from a smooth surface to a hill-and-valley surface. The lattice constant of the hill-and-valley structure amounts to 3.16 Å, which is exactly the lattice constant of pristine MoS2. (2 The transitions from hills to valleys are not abrupt, as one would expect for epitaxial islands growing on-top of a substrate, but very gradual. (3 I(V scanning tunneling spectroscopy spectra recorded at the hills and valleys reveal no noteworthy differences. (4 Spatial maps of dI/dz reveal that the surface exhibits a uniform work function and a lattice constant of 3.16 Å. (5 X-ray photo-electron spectroscopy measurements reveal that sputtering of the MoS2/Si substrate does not lead to a decrease, but an increase of the relative Si signal. Based on these experimental observations we have to conclude that deposited Si atoms do not reside on the MoS2 surface, but rather intercalate between the MoS2 layers. Our conclusion that Si intercalates upon the deposition on MoS2 is at variance with the interpretation by Chiappe et al. (Adv. Mater. 2014, 26, 2096–2101 that silicon forms a highly strained epitaxial layer on MoS2. Finally, density functional theory calculations indicate that silicene clusters encapsulated by MoS2 are stable.

  12. Update: An efficient synthesis of poly(ethylene glycol)-supported iron(II) porphyrin using a click reaction and its application for the catalytic olefination of aldehydes

    KAUST Repository

    Chinnusamy, Tamilselvi R.

    2012-05-09

    The facile synthesis of polyethylene glycol (PEG)-immobilized iron(II) porphyrin using a copper-catalyzed azide-alkyne [3+2] cycloaddition "click" reaction is reported. The prepared complex 5 (PEG-C 51H 39FeN 7O) was found to be an efficient catalyst for the selective olefination of aldehydes with ethyl diazoacetate in the presence of triphenylphosphine, and afforded excellent olefin yields with high (E) selectivities. The PEG-supported catalyst 5 was readily recovered by precipitation and filtration, and was recycled through ten runs without significant activity loss. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Large-scale synthesis of high-purity well-aligned carbon nanotubes using pyrolysis of iron(II) phthalocyanine and acetylene

    Science.gov (United States)

    Liu, B. C.; Lee, T. J.; Lee, S. H.; Park, C. Y.; Lee, C. J.

    2003-08-01

    Well-aligned carbon nanotubes (CNTs) with high purity have been produced by pyrolysis of iron(II) phthalocyanine and acetylene at 800 °C. The synthesized CNTs have a length of 75 μm and diameters ranging from 20 to 60 nm. The CNTs have a bamboo-like structure and exhibit good crystallinity of graphite sheets. The growth rate of the CNTs was rapidly increased with adding C 2H 2. Our results demonstrate that the proposed growth method is suitable to large-scale synthesis of high-purity well-aligned CNTs on various substrates.

  14. Intercalation of small hydrophobic molecules in lipid bilayers containing cholesterol

    Energy Technology Data Exchange (ETDEWEB)

    Worcester, D.L.; Hamacher, K.; Kaiser, H.; Kulasekere, R.; Torbet, J. [Univ. of Missouri, Columbia, MO (United States)

    1994-12-31

    Partitioning of small hydrophobic molecules into lipid bilayers containing cholesterol has been studied using the 2XC diffractometer at the University of Missouri Research Reactor. Locations of the compounds were determined by Fourier difference methods with data from both deuterated and undeuterated compounds introduced into the bilayers from the vapor phase. Data fitting procedures were developed for determining how well the compounds were localized. The compounds were found to be localized in a narrow region at the center of the hydrophobic layer, between the two halves of the bilayer. The structures are therefore intercalated structures with the long axis of the molecules in the plane of the bilayer.

  15. Preparation and capacitive properties of lithium manganese oxide intercalation compound

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Fang; Xie, Yibing, E-mail: ybxie@seu.edu.cn [Southeast University, School of Chemistry and Chemical Engineering (China)

    2015-12-15

    Lithium manganese oxide intercalation compound (Li{sub 0.7}MnO{sub 2}) supported on titanium nitride nanotube array (TiN NTA) was applied as cathode electrode material for lithium-ion supercapacitor application. Li{sub 0.7}MnO{sub 2}/TiN NTA was fabricated through electrochemical deposition and simultaneous intercalation process using TiN NTA as a substrate, Mn(CH{sub 3}COO){sub 2} as manganese source, and Li{sub 2}SO{sub 4} as lithium source. The morphology and microstructure of the Li{sub 0.7}MnO{sub 2}/TiN NTA were characterized by scanning electron microscopy and X-ray diffraction analysis. The electrochemical performance of the Li{sub 0.7}MnO{sub 2}/TiN NTA was investigated by electrochemical impedance spectroscopy, cyclic voltammetry, and galvanostatic charge/discharge measurements. Li{sub 0.7}MnO{sub 2}/TiN NTA exhibited higher capacitive performance in Li{sub 2}SO{sub 4} electrolyte solution rather than that in Na{sub 2}SO{sub 4} electrolyte solution, which was due to the different intercalation effects of lithium-ion and sodium-ion. The specific capacitance was improved from 503.3 F g{sup −1} for MnO{sub 2}/TiN NTA to 595.0 F g{sup −1} for Li{sub 0.7}MnO{sub 2}/TiN NTA at a current density of 2 A g{sup −1} in 1.0 M Li{sub 2}SO{sub 4} electrolyte solution, which was due to the intercalation of lithium-ion for Li{sub 0.7}MnO{sub 2}. Li{sub 0.7}MnO{sub 2}/TiN NTA also kept 90.4 % capacity retention after 1000 cycles, presenting a good cycling stability. An all-solid-state lithium-ion supercapacitor was fabricated and showed an energy density of 82.5 Wh kg{sup −1} and a power density of 10.0 kW kg{sup −1}.

  16. DNA intercalator stimulates influenza transcription and virus replication

    Directory of Open Access Journals (Sweden)

    Poon Leo LM

    2011-03-01

    Full Text Available Abstract Influenza A virus uses its host transcription machinery to facilitate viral RNA synthesis, an event that is associated with cellular RNA polymerase II (RNAPII. In this study, various RNAPII transcription inhibitors were used to investigate the effect of RNAPII phosphorylation status on viral RNA transcription. A low concentration of DNA intercalators, such as actinomycin D (ActD, was found to stimulate viral polymerase activity and virus replication. This effect was not observed in cells treated with RNAPII kinase inhibitors. In addition, the loss of RNAPIIa in infected cells was due to the shift of nonphosphorylated RNAPII (RNAPIIa to hyperphosphorylated RNAPII (RNAPIIo.

  17. Intercalation of small hydrophobic molecules in lipid bilayers containing cholesterol

    International Nuclear Information System (INIS)

    Worcester, D.L.; Hamacher, K.; Kaiser, H.; Kulasekere, R.; Torbet, J.

    1994-01-01

    Partitioning of small hydrophobic molecules into lipid bilayers containing cholesterol has been studied using the 2XC diffractometer at the University of Missouri Research Reactor. Locations of the compounds were determined by Fourier difference methods with data from both deuterated and undeuterated compounds introduced into the bilayers from the vapor phase. Data fitting procedures were developed for determining how well the compounds were localized. The compounds were found to be localized in a narrow region at the center of the hydrophobic layer, between the two halves of the bilayer. The structures are therefore intercalated structures with the long axis of the molecules in the plane of the bilayer

  18. Capacitors on the basis of intercalate GaSe

    Directory of Open Access Journals (Sweden)

    Kovalyuk Z. D.

    2010-06-01

    Full Text Available The compound GaSe is obtained by the technique of intercalation of a GaSe single crystal in a melt of the ferroelectric salt KNO3. The x-ray analysis of its crystal structure has been carried out and dielectric frequency characteristics of samples has been measured. It is estab-lished, that accumulation of electric charges occurs in the examined examples in frequency area 100—1000 Hz. A sample of filter capacitor has been created on the basis of the re-ceived compounds.

  19. Physical properties of C60 intercalated graphite films

    International Nuclear Information System (INIS)

    Nakahara, T; Hosomi, N; Taniguchi, J; Suzuki, M; Sato, T; Abe, K; Kuwahara, D; Ishikawa, M; Kato, M; Miura, K

    2007-01-01

    Recently, Miura and Tsuda have synthesized C 60 intercalated graphite film (C 60 /Gr) and reported that the C 60 /Gr consists of alternating close-packed C 60 monolayers and graphite layers. They also found that its frictional force is minimal up to the loading force of 100 nN using AFM [Miura K and Tsuda D 2005 e-J. Surf. Sci. Nanotech. 3 21] Thus, we have started to study the physical properties of C 60 /Gr and carried out NMR, Raman scattering and specific heat measurements. These results suggest that C 60 in C 60 /Gr rotates at room temperature

  20. Synthesis and structural characterisation of iron(II) and copper(II) diphosphates containing flattened metal oxotetrahedra

    International Nuclear Information System (INIS)

    Keates, Adam C.; Wang, Qianlong; Weller, Mark T.

    2014-01-01

    Single crystal and bulk polycrystalline forms of K 2 MP 2 O 7 (M=Fe(II), Cu(II)) have been synthesised and their structures determined from single crystal X-ray diffraction data. Both compounds crystallize in the tetragonal system, space group P-42 1 m. Their structures are formed from infinite sheets of linked oxopolyhedra of the stoichiometry [MP 2 O 7 ] 2− with potassium cations situated between the layers. The MO 4 tetrahedra share oxygen atoms with [P 2 O 7 ] 4− diphosphate groups and the potassium ions have KO 8 square prismatic geometry. In both compounds the M(II) centre has an unusual strongly flattened, tetrahedral coordination to oxygen, as a result of the Jahn–Teller (JT) effect for the high spin d 6 Fe(II) and p-orbital mixing or a second order JT effect for d 9 Cu(II) centres in four fold coordination. The uncommon transition metal ion environments found in these materials are reflected in their optical absorption spectra and magnetism data. - Graphical abstract: The structures of the tetragonal polymorphs of K 2 MP 2 O 7 , M=Cu(II), Fe(II), consist of infinite sheets of stoichiometry [MP 2 O 7 ] 2− , formed from linked pyrophosphate groups and MO 4 tetrahedra, separated by potassium ions. In both compounds the unusual tetrahedral coordination of the M(II) centre is strongly flattened as a result of Jahn–Teller (JT) effects for high spin, d 6 Fe(II) and p-orbital mixing and second-order JT effects for d 9 Cu(II). Display Omitted - Highlights: • Tetrahedral copper and iron(II) coordinated by oxygen. • New layered phosphate structure. • Jahn–Teller and d 10 distorted coordinations

  1. A novel method of adrenaline concentration detection using fiber optical biosensor based on the catalysis of iron(II) phthalocyanine

    Science.gov (United States)

    Zhou, Xuan; Huang, Jun; Li, Mingtian; Wang, Bin

    2008-12-01

    As an effective alternative to the nature enzyme, metallophthalocyanine (MPc), having the advantages of easy accessibility, good stability and low cost, are used as catalyzer for the adrenaline (AD) oxidation. In this paper, the oxidation of AD by dioxygen using iron(II) phthalocyanine (FePc) as the catalyst was studied by electronic absorption spectra. The experimental results indicate that the oxidation product of AD catalyzed by FePc is adrenochrome with characteristic peaks at 298 nm and 267 nm. The catalytic activities of FePc are evaluated by the ratios of the absorbance at 298 nm of adrenochrome. The optimal concentration, pH and temperature for the oxidation of AD are 5.0×10-5 M, 8.0 and 55 oC, respectively. By using lock-in technology, the fiber optic adrenaline biosensor based on FePc catalysis and fluorescence quenching was fabricated and studied. A linear relationship between φ, the phase delay of the sensor head, and AD concentration was observed in the range of 2.0×10-6 to 9.0×10-6 M and 2.0×10-5 to 9.0×10-5 M. The standard deviation (SD) values are 4.7×10-8 (n = 5) and 5.9×10-7 (n = 5) M, respectively, while the detection limit is 4.0×10-7 M. The biosensor has the response time of about 15 min and the preferred reproducibility and stability.

  2. Kinetic, spectroscopic and chemical modification study of iron release from transferrin; iron(III) complexation to adenosine triphosphate

    International Nuclear Information System (INIS)

    Thompson, C.P.

    1985-01-01

    Amino acids other than those that serve as ligands have been found to influence the chemical properties of transferrin iron. The catalytic ability of pyrophosphate to mediate transferrin iron release to a terminal acceptor is largely quenched by modification non-liganded histine groups on the protein. The first order rate constants of iron release for several partially histidine modified protein samples were measured. A statistical method was employed to establish that one non-liganded histidine per metal binding domain was responsible for the reduction in rate constant. These results imply that the iron mediated chelator, pyrophosphate, binds directly to a histidine residue on the protein during the iron release process. EPR spectroscopic results are consistent with this interpretation. Kinetic and amino acid sequence studies of ovotransferrin and lactoferrin, in addition to human serum transferrin, have allowed the tentative assignment of His-207 in the N-terminal domain and His-535 in the C-terminal domain as the groups responsible for the reduction in rate of iron release. The above concepts have been extended to lysine modified transferrin. Complexation of iron(II) to adenosine triphosphate (ATP) was also studied to gain insight into the nature of iron-ATP species present at physiological pH. 31 P NMR spectra are observed when ATP is presented in large excess

  3. Controlling Water Intercalation Is Key to a Direct Graphene Transfer.

    Science.gov (United States)

    Verguts, Ken; Schouteden, Koen; Wu, Cheng-Han; Peters, Lisanne; Vrancken, Nandi; Wu, Xiangyu; Li, Zhe; Erkens, Maksiem; Porret, Clement; Huyghebaert, Cedric; Van Haesendonck, Chris; De Gendt, Stefan; Brems, Steven

    2017-10-25

    The key steps of a transfer of two-dimensional (2D) materials are the delamination of the as-grown material from a growth substrate and the lamination of the 2D material on a target substrate. In state-of-the-art transfer experiments, these steps remain very challenging, and transfer variations often result in unreliable 2D material properties. Here, it is demonstrated that interfacial water can insert between graphene and its growth substrate despite the hydrophobic behavior of graphene. It is understood that interfacial water is essential for an electrochemistry-based graphene delamination from a Pt surface. Additionally, the lamination of graphene to a target wafer is hindered by intercalation effects, which can even result in graphene delamination from the target wafer. For circumvention of these issues, a direct, support-free graphene transfer process is demonstrated, which relies on the formation of interfacial water between graphene and its growth surface, while avoiding water intercalation between graphene and the target wafer by using hydrophobic silane layers on the target wafer. The proposed direct graphene transfer also avoids polymer contamination (no temporary support layer) and eliminates the need for etching of the catalyst metal. Therefore, recycling of the growth template becomes feasible. The proposed transfer process might even open the door for the suggested atomic-scale interlocking-toy-brick-based stacking of different 2D materials, which will enable a more reliable fabrication of van der Waals heterostructure-based devices and applications.

  4. Intercalation of cellulase enzyme into a hydrotalcite layer structure

    Science.gov (United States)

    Zou, N.; Plank, J.

    2015-01-01

    A new inorganic-organic hybrid material whereby cellulase enzyme is incorporated into a hydrotalcite type layered double hydroxide (LDH) structure is reported. The Mg2Al-cellulase-LDH was synthesized via co-precipitation from Mg/Al nitrate at pH=9.6. Characterization was performed using X-ray powder diffraction (XRD), small angle X-ray scattering (SAXS), elemental analysis, infrared spectroscopy (IR) and thermogravimetry (TG). From XRD and SAXS measurements, a d-value of ~5.0 nm was identified for the basal spacing of the Mg2Al-cellulase-LDH. Consequently, the cellulase enzyme (hydrodynamic diameter ~6.6 nm) attains a slightly compressed conformation when intercalated. Formation of the LDH hybrid was also confirmed via scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Mg2Al-cellulase-LDH phases appear as ~20 nm thin foils which are intergrown to flower-like aggregates. Activity of the enzyme was retained after deintercalation from the Mg2Al-LDH framework using anion exchange. Accordingly, cellulase is not denatured during the intercalation process, and LDH presents a suitable host structure for time-controlled release of the biomolecule.

  5. Tunable Broadband Nanocarbon Transparent Conductor by Electrochemical Intercalation.

    Science.gov (United States)

    Wan, Jiayu; Xu, Yue; Ozdemir, Burak; Xu, Lisha; Sushkov, Andrei B; Yang, Zhi; Yang, Bao; Drew, Dennis; Barone, Veronica; Hu, Liangbing

    2017-01-24

    Optical transparent and electrical conducting materials with broadband transmission are important for many applications in optoelectronic, telecommunications, and military devices. However, studies of broadband transparent conductors and their controlled modulation are scarce. In this study, we report that reversible transmittance modulation has been achieved with sandwiched nanocarbon thin films (containing carbon nanotubes (CNTs) and reduced graphene oxide (rGO)) via electrochemical alkali-ion intercalation/deintercalation. The transmittance modulation covers a broad range from the visible (450 nm) to the infrared (5 μm), which can be achieved only by rGO rather than pristine graphene films. The large broadband transmittance modulation is understood with DFT calculations, which suggest a decrease in interband transitions in the visible range as well as a reduced reflection in the IR range upon intercalation. We find that a larger interlayer distance in few-layer rGO results in a significant increase in transparency in the infrared region of the spectrum, in agreement with experimental results. Furthermore, a reduced plasma frequency in rGO compared to few-layer graphene is also important to understand the experimental results for broadband transparency in rGO. The broadband transmittance modulation of the CNT/rGO/CNT systems can potentially lead to electrochromic and thermal camouflage applications.

  6. Electron Beam Irradiated Intercalated CNT Yarns For Aerospace Applications

    Science.gov (United States)

    Waters, Deborah L.; Gaier, James R.; Williams, Tiffany S.; Lopez Calero, Johnny E.; Ramirez, Christopher; Meador, Michael A.

    2015-01-01

    Multi-walled CNT yarns have been experimentally and commercially created to yield lightweight, high conductivity fibers with good tensile properties for application as electrical wiring and multifunctional tendons. Multifunctional tendons are needed as the cable structures in tensegrity robots for use in planetary exploration. These lightweight robust tendons can provide mechanical strength for movement of the robot in addition to power distribution and data transmission. In aerospace vehicles, such as Orion, electrical wiring and harnessing mass can approach half of the avionics mass. Use of CNT yarns as electrical power and data cables could reduce mass of the wiring by thirty to seventy percent. These fibers have been intercalated with mixed halogens to increase their specific electrical conductivity to that near copper. This conductivity, combined with the superior strength and fatigue resistance makes it an attractive alternative to copper for wiring and multifunctional tendon applications. Electron beam irradiation has been shown to increase mechanical strength in pristine CNT fibers through increased cross-linking. Both pristine and intercalated CNT yarns have been irradiated using a 5-megavolt electron beam for various durations and the conductivities and tensile properties will be discussed. Structural information obtained using a field emission scanning electron microscope, energy dispersive X-ray spectroscopy (EDS), and Raman spectroscopy will correlate microstructural details with bulk properties.

  7. Ion transport and phase transformation in thin film intercalation electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Wunde, Fabian; Nowak, Susann; Muerter, Juliane; Hadjixenophontos, Efi; Berkemeier, Frank; Schmitz, Guido [Stuttgart Univ. (Germany). Inst. fuer Materialwissenschaft

    2017-11-15

    Thin film battery electrodes of the olivine structure LiFePO{sub 4} and the spinel phase LiMn{sub 2}O{sub 4} are deposited through ion-beam sputtering. The intercalation kinetics is studied by cyclo-voltammetry using variation of the cycling rate over 4 to 5 orders of magnitude. The well-defined layer geometry allows a detailed quantitative analysis. It is shown that LiFePO{sub 4} clearly undergoes phase separation during intercalation, although the material is nano-confined and very high charging rates are applied. We present a modified Randles-Sevcik evaluation adapted to phase-separating systems. Both the charging current and the overpotential depend on the film thickness in a systematic way. The analysis yields evidence that the grain boundaries are important short circuit paths for fast transport. They increase the electrochemical active area with increasing layer thickness. Evidence is obtained that the grain boundaries in LiFePO{sub 4} have the character of an ion-conductor of vanishing electronic conductivity.

  8. Intercalation of alcohols in Ag sulfonates: topotactic behavior despite flexible layers.

    Science.gov (United States)

    Côté, Adrien P; Ferguson, Michael J; Khan, Kashif A; Enright, Gary D; Kulynych, Angela D; Dalrymple, Sean A; Shimizu, George K H

    2002-01-28

    This article presents the inaugural intercalation study of a layered metal sulfonate network. Silver triflate forms intercalation complexes with straight chain primary alcohols from ethanol (C(2)H(5)OH) to eicosanol (C(20)H(41)OH). Single-crystal data for the EtOH adduct, 1, are presented which show that the intercalation is coordinative to Ag. In contrast to many other layered hosts, no preheating of Ag triflate is required to liberate a coordination site for intercalation to take place, owing to the ability of the triflate ion to reorient. Crystal structure parameters for 1: C(4)H(6)F(6)S(2)O(7)Ag(2), a = 5.345(7) A, b = 11.310(2) A, c = 12.004(2) A, alpha = 116.87(1) degrees, beta = 90.46(1) degrees, gamma = 99.59(1) degrees, triclinic, space group P, Z = 2. Intercalate 1 presents the triflate ion in an unprecedented mu(5)-coordination mode. PXRD data on the family of complexes show that the intercalation is topotactic, as verified by the linear increase in d-spacing and calculated c-axis lengths for the intercalates, with increasing chain length. The data also show that the alcohol intercalates adopt an interdigitated rather than bilayer arrangement.

  9. Impedance Simulation of a Li-Ion Battery with Porous Electrodes and Spherical Li+ Intercalation Particles

    NARCIS (Netherlands)

    Huang, R.W.J.M.; Chung, F.; Kelder, E.M.

    2006-01-01

    We present a semimathematical model for the simulation of the impedance spectra of a rechargeable lithium batteries consisting of porous electrodes with spherical Li+ intercalation particles. The particles are considered to have two distinct homogeneous phases as a result of the intercalation and

  10. Potassium-intercalated H2Pc films : Alkali-induced electronic and geometrical modifications

    NARCIS (Netherlands)

    Nilson, K.; Ahlund, J.; Shariati, M. -N.; Schiessling, J.; Palmgren, P.; Brena, B.; Gothelid, E.; Hennies, F.; Huismans, Y.; Evangelista, F.; Rudolf, P.; Gothelid, M.; Martensson, N.; Puglia, C.; Åhlund, J.; Göthelid, E.; Göthelid, M.; Mårtensson, N.

    2012-01-01

    X-ray spectroscopy studies of potassium intercalated metal-free phthalocyanine multilayers adsorbed on Al(110) have been undertaken. Photoelectron spectroscopy measurements show the presence of several charge states of the molecules upon K intercalation, due to a charge transfer from the alkali. In

  11. Stabilization of chromosomes by DNA intercalators for flow karyotyping and identification by banding of isolated chromosomes

    NARCIS (Netherlands)

    Aten, J. A.; Buys, C. H.; van der Veen, A. Y.; Mesa, J. R.; Yu, L. C.; Gray, J. W.; Osinga, J.; Stap, J.

    1987-01-01

    A number of structurally unrelated DNA intercalators have been studied as stabilizers of mitotic chromosomes during isolation from rodent and human metaphase cells. Seven out of the nine intercalators tested were found to be useful as chromosome stabilizing agents. Chromosome suspensions prepared in

  12. Optical determination of the electronic coupling and intercalation geometry of thiazole orange homodimer in DNA

    Science.gov (United States)

    Cunningham, Paul D.; Bricker, William P.; Díaz, Sebastián A.; Medintz, Igor L.; Bathe, Mark; Melinger, Joseph S.

    2017-08-01

    Sequence-selective bis-intercalating dyes exhibit large increases in fluorescence in the presence of specific DNA sequences. This property makes this class of fluorophore of particular importance to biosensing and super-resolution imaging. Here we report ultrafast transient anisotropy measurements of resonance energy transfer (RET) between thiazole orange (TO) molecules in a complex formed between the homodimer TOTO and double-stranded (ds) DNA. Biexponential homo-RET dynamics suggest two subpopulations within the ensemble: 80% intercalated and 20% non-intercalated. Based on the application of the transition density cube method to describe the electronic coupling and Monte Carlo simulations of the TOTO/dsDNA geometry, the dihedral angle between intercalated TO molecules is estimated to be 81° ± 5°, corresponding to a coupling strength of 45 ± 22 cm-1. Dye intercalation with this geometry is found to occur independently of the underlying DNA sequence, despite the known preference of TOTO for the nucleobase sequence CTAG. The non-intercalated subpopulation is inferred to have a mean inter-dye separation distance of 19 Å, corresponding to coupling strengths between 0 and 25 cm-1. This information is important to enable the rational design of energy transfer systems that utilize TOTO as a relay dye. The approach used here is generally applicable to determining the electronic coupling strength and intercalation configuration of other dimeric bis-intercalators.

  13. Dynamics of Intercalation/De-Intercalation of Rhodamine B during the Polymorphic Transformation of CdAl Layered Double Hydroxide to the Brucite-Like Cadmium Hydroxide

    KAUST Repository

    Saliba, Daniel

    2016-06-23

    Cadmium-Aluminum layered double hydroxide (CdAl LDH) is thermodynamically unstable and transforms to Cd(OH)2 and Al(OH)3 in a short period of time. We present a reaction-diffusion framework that enables us to use in situ steady-state fluorescence spectroscopy to study the kinetics of intercalation of a fluorescent probe (Rhodamine B (RhB)) during the formation of the CdAl LDH and its de-intercalation upon the conversion of the LDH phase to the β phase (Cd(OH)2). The method involves the diffusion of sodium hydroxide into a hydrogel gel matrix containing the aluminum and cadmium ions as well as the species we wish to incorporate in the interlayers of the LDH. The existence of RhB between the LDH layers and its expel during the transition into the β phase are proved via fluorescence microscopy, XRD and ssNMR. The activation energies of intercalation and de-intercalation of RhB are computed and show dependence on the cationic ratio of the corresponding LDH. We find that the energies of de- intercalation are systematically higher than those of intercalation proving that the dyes are stabilized due to the probe-brucite sheets interactions.

  14. Dynamics of Intercalation/De-Intercalation of Rhodamine B during the Polymorphic Transformation of CdAl Layered Double Hydroxide to the Brucite-Like Cadmium Hydroxide

    KAUST Repository

    Saliba, Daniel; Ezzeddine, Alaa; Emwas, Abdul-Hamid M.; Khashab, Niveen M.; Al-Ghoul, Mazen

    2016-01-01

    Cadmium-Aluminum layered double hydroxide (CdAl LDH) is thermodynamically unstable and transforms to Cd(OH)2 and Al(OH)3 in a short period of time. We present a reaction-diffusion framework that enables us to use in situ steady-state fluorescence spectroscopy to study the kinetics of intercalation of a fluorescent probe (Rhodamine B (RhB)) during the formation of the CdAl LDH and its de-intercalation upon the conversion of the LDH phase to the β phase (Cd(OH)2). The method involves the diffusion of sodium hydroxide into a hydrogel gel matrix containing the aluminum and cadmium ions as well as the species we wish to incorporate in the interlayers of the LDH. The existence of RhB between the LDH layers and its expel during the transition into the β phase are proved via fluorescence microscopy, XRD and ssNMR. The activation energies of intercalation and de-intercalation of RhB are computed and show dependence on the cationic ratio of the corresponding LDH. We find that the energies of de- intercalation are systematically higher than those of intercalation proving that the dyes are stabilized due to the probe-brucite sheets interactions.

  15. Effectiveness of Co intercalation between Graphene and Ir(1 1 1)

    Science.gov (United States)

    Carlomagno, I.; Drnec, J.; Scaparro, A. M.; Cicia, S.; Mobilio, S.; Felici, R.; Meneghini, C.

    2018-04-01

    Graphene can be used to avoid the oxidation of metallic films. This work explores the effectiveness of such stabilizing effect on Cobalt (Co) films intercalated between Graphene and Ir(1 1 1). After intercalation at 300 °C, two Co films are exposed to ambient pressure and investigated using Co-K edge X-ray Absorption Near Edge Spectroscopy. The formation of a disordered oxide phase is observed, and associated to the presence of some non-intercalated Co. Further annealing at 500 °C causes the oxide reduction to metallic Co which further intercalates below the Graphene. Once the intercalation is completed, Graphene prevents the Co from oxidation under ambient pressure conditions.

  16. First-Principles Study of Lithium and Sodium Atoms Intercalation in Fluorinated Graphite

    Directory of Open Access Journals (Sweden)

    Fengya Rao

    2015-06-01

    Full Text Available The structure evolution of fluorinated graphite (CFx upon the Li/Na intercalation has been studied by first-principles calculations. The Li/Na adsorption on single CF layer and intercalated into bulk CF have been calculated. The better cycling performance of Na intercalation into the CF cathode, comparing to that of Li intercalation, is attributed to the different strength and characteristics of the Li-F and Na-F interactions. The interactions between Li and F are stronger and more localized than those between Na and F. The strong and localized Coulomb attraction between Li and F atoms breaks the C−F bonds and pulls the F atoms away, and graphene sheets are formed upon Li intercalation.

  17. Atomic force microscopy study of anion intercalation into highly oriented pyrolytic graphite

    Energy Technology Data Exchange (ETDEWEB)

    Alliata, D; Haering, P; Haas, O; Koetz, R [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Siegenthaler, H [University of Berne (Switzerland)

    1999-08-01

    In the context of ion transfer batteries, we studied highly oriented pyrolytic graphite (HOPG) in perchloric acid, as a model to elucidate the mechanism of electrochemical intercalation in graphite. Aim of the work is the local and time dependent investigation of dimensional changes of the host material during electrochemical intercalation processes on the nanometer scale. We used atomic force microscopy (AFM), combined with cyclic voltammetry, as in-situ tool of analysis during intercalation and expulsion of perchloric anions into the HOPG electrodes. According to the AFM measurements, the HOPG interlayer spacing increases by 32% when perchloric anions intercalate, in agreement with the formation of stage IV of graphite intercalation compounds. (author) 3 figs., 3 refs.

  18. Interlayer Structure of Bioactive Molecule, 2-Aminoethanesulfonate, Intercalated into Calcium-Containing Layered Double Hydroxides

    Directory of Open Access Journals (Sweden)

    Tae-Hyun Kim

    2012-01-01

    Full Text Available We have successfully intercalated 2-aminoethanesulfonate, a well-known biomolecule taurine, into calcium-containing layered double hydroxides via optimized solid phase intercalation. According to X-ray diffraction patterns and infrared spectroscopy, it was revealed that the intercalated taurine molecules were each directly coordinated to other calcium cation and arranged in a zig-zag pattern. Scanning electron microscopy showed that the particle size and morphology of the LDHs were not affected by the solid phase intercalation, and the surface of intercalates was covered by organic moieties. From ninhydrin amine detection tests, we confirmed that most of the taurine molecules were well stabilized between the calcium-containing LDH layers.

  19. Ab initio density functional theory investigation of Li-intercalated silicon carbide nanotube bundles

    International Nuclear Information System (INIS)

    Moradian, Rostam; Behzad, Somayeh; Chegel, Raad

    2009-01-01

    We present the results of ab initio density functional theory calculations on the energetic, and geometric and electronic structure of Li-intercalated (6,6) silicon carbide nanotube (SiCNT) bundles. Our results show that intercalation of lithium leads to the significant changes in the geometrical structure. The most prominent effect of Li intercalation on the electronic band structure is a shift of the Fermi energy which occurs as a result of charge transfer from lithium to the SiCNTs. All the Li-intercalated (6,6) SiCNT bundles are predicted to be metallic representing a substantial change in electronic properties relative to the undoped bundle, which is a wide band gap semiconductor. Both inside of the nanotube and the interstitial space are susceptible for intercalation. The present calculations suggest that the SiCNT bundle is a promising candidate for the anode material in battery applications.

  20. Ab initio density functional theory investigation of Li-intercalated silicon carbide nanotube bundles

    Science.gov (United States)

    Moradian, Rostam; Behzad, Somayeh; Chegel, Raad

    2009-06-01

    We present the results of ab initio density functional theory calculations on the energetic, and geometric and electronic structure of Li-intercalated ( 6,6) silicon carbide nanotube (SiCNT) bundles. Our results show that intercalation of lithium leads to the significant changes in the geometrical structure. The most prominent effect of Li intercalation on the electronic band structure is a shift of the Fermi energy which occurs as a result of charge transfer from lithium to the SiCNTs. All the Li-intercalated ( 6,6) SiCNT bundles are predicted to be metallic representing a substantial change in electronic properties relative to the undoped bundle, which is a wide band gap semiconductor. Both inside of the nanotube and the interstitial space are susceptible for intercalation. The present calculations suggest that the SiCNT bundle is a promising candidate for the anode material in battery applications.

  1. Ab initio density functional theory investigation of Li-intercalated silicon carbide nanotube bundles

    Energy Technology Data Exchange (ETDEWEB)

    Moradian, Rostam [Physics Department, Faculty of Science, Razi University, Kermanshah (Iran, Islamic Republic of); Nano Science and Technology Research Center, Razi University, Kermanshah (Iran, Islamic Republic of); Computational Physical Science Research Laboratory, Department of Nano Science, Institute for Studies in Theoretical Physics and Mathematics (IPM), PO Box 19395-5531, Tehran (Iran, Islamic Republic of)], E-mail: moradian.rostam@gmail.com; Behzad, Somayeh; Chegel, Raad [Physics Department, Faculty of Science, Razi University, Kermanshah (Iran, Islamic Republic of)

    2009-06-15

    We present the results of ab initio density functional theory calculations on the energetic, and geometric and electronic structure of Li-intercalated (6,6) silicon carbide nanotube (SiCNT) bundles. Our results show that intercalation of lithium leads to the significant changes in the geometrical structure. The most prominent effect of Li intercalation on the electronic band structure is a shift of the Fermi energy which occurs as a result of charge transfer from lithium to the SiCNTs. All the Li-intercalated (6,6) SiCNT bundles are predicted to be metallic representing a substantial change in electronic properties relative to the undoped bundle, which is a wide band gap semiconductor. Both inside of the nanotube and the interstitial space are susceptible for intercalation. The present calculations suggest that the SiCNT bundle is a promising candidate for the anode material in battery applications.

  2. Iron(II) complexes of new hexadentate 1,1,1-tris-(iminomethyl)ethane podands, and their 7-methyl-1,3,5-triazaadamantane rearrangement products.

    Science.gov (United States)

    Diener, Sara A; Santoro, Amedeo; Kilner, Colin A; Loughrey, Jonathan J; Halcrow, Malcolm A

    2012-04-07

    New iron(II) podand complexes have been prepared, by condensation of 2-(aminomethyl)-2-methyl-1,3-diaminopropane with 3 equiv of a heterocyclic aldehyde in the presence of hydrated Fe[BF(4)](2) or Fe[ClO(4)](2) as templates. The 2-(aminomethyl)-2-methyl-1,3-diaminopropane is prepared in situ by deprotonation of its trihydrochloride salt. The chloride must be removed from these reactions by precipitation with silver, to avoid the formation of the alternative 2,4,6-trisubstituted-7-methyl-1,3,5-triazaadamantane condensation products, or their FeCl(2) adducts. The crystal structures of two 2,4,6-tri(pyridyl)-7-methyl-1,3,5-triazaadamantane-containing species are presented, and contain two different geometric isomers of this tricyclic ring with three equatorial, or two equatorial and one axial, pyridyl substituents. Both structures feature strong C-HX (X = Cl or F) hydrogen bonding from the aminal C-H groups in the triazaadamantane ring. Five iron(II) podand complexes were successfully obtained, all of which contain low-spin iron centres.

  3. Iron(III) diethylenetriaminepentaacetic acid complex on polyallylamine functionalized multiwalled carbon nanotubes: immobilization, direct electrochemistry and electrocatalysis.

    Science.gov (United States)

    Liu, Hailing; Cui, Yanyun; Li, Pan; Zhou, Yiming; Zhu, Xiaoshu; Tang, Yawen; Chen, Yu; Lu, Tianhong

    2013-05-07

    A nonenzymatic iron(III) diethylenetriaminepentaacetic acid (Fe(III)-DETPA) complex based amperometric sensor for the analytical determination of hydrogen peroxide was developed. By combining the electrostatic interaction between the Fe(III)-DETPA complex and polyallylamine (PAH) functionalized multiwalled carbon nanotubes (MWCNTs) as well as the ionotropic crosslinking interaction between PAH and ethylenediamine-tetramethylene phosphonic acid (EDTMP), the electroactive Fe(III)-DETPA complex was successfully incorporated within the MWCNT matrix, and firmly immobilized on the Au substrate electrode. The fabricated electrochemical sensor was characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electrochemical methods. The influences of solution pH and ionic strength on the electrochemical sensor were investigated. The prepared electrochemical sensor had a fast response to hydrogen peroxide (<3 s) and an excellent linear range of concentration from 1.25 × 10(-8) to 4.75 × 10(-3) M with a detection limit of 6.3 × 10(-9) M under the optimum conditions.

  4. Kinetics and mechanism of reduction of iron(iii) kojic acid complex by hydroquinone and l-cysteine

    International Nuclear Information System (INIS)

    Hussain, Z.; Perviaz, M.; Kazmi, S.A.; Johnson, A.S.; Offiong, O.E.

    2014-01-01

    The effect of pH on the kinetics of reduction of iron(III) kojic acid complex by hydroquinone (H/sub 2/Q) and L-cysteine (L-Cys) was studied in the pH range of 2.34 - 4.03 for H/sub 2/Q and 3.04 - 5.5 for L-cysteine at ionic strength of 0.5 M and at 35 degree C. The pseudo-first order rate constants for the reduction of Fe(KA)3 by L-cysteine and hydroquinone increase linearly with increasing reductant concentration, indicating first-order kinetics in reductant concentration. However, whereas the rate of reduction by H2Q increases with increasing pH, an opposite trend was observed in the case of reduction by L-cysteine. Plausible rate laws and mechanisms have been proposed in line with these observations. Activation parameters (delta H no and delta S no) were evaluated for the reduction of iron (III) kojic acid complex by cysteine and the values obtained are 35.25 kJmol-1, -141.4 JK-1mol-1 and 28.14 kJmol-1 , 161.2 JK-1mol-1 for pH 4.5 and 3.52 respectively. (author)

  5. Iron(III) protoporphyrin IX-single-wall carbon nanotubes modified electrodes for hydrogen peroxide and nitrite detection

    International Nuclear Information System (INIS)

    Turdean, Graziella L.; Popescu, Ionel Catalin; Curulli, Antonella; Palleschi, Giuseppe

    2006-01-01

    Iron(III) protoporphyrin IX (Fe(III)P), adsorbed either on single-walled carbon nanotubes (SWCNT) or on hydroxyl-functionalized SWCNT (SWCNT-OH), was incorporated within a Nafion matrix immobilized on the surface of a graphite electrode. From cyclic voltammetric measurements, performed under different experimental conditions (pH and potential scan rate), it was established that the Fe(III)P/Fe(II)P redox couple involves 1e - /1H + . The heterogeneous electron transfer process occurred faster when Fe(III)P was adsorbed on SWCNT-OH (∼11 s -1 ) than on SWCNT (∼4.9 s -1 ). Both the SWCNT-Fe(III)P- and SWCNT-OH-Fe(III)P-modified graphite electrodes exhibit electrocatalytic activity for H 2 O 2 and nitrite reduction. The modified electrodes sensitivities were found varying in the following sequences: S SWCNT-OH-Fe(III)P = 2.45 mA/M ∼ S SWCNT-Fe(III)P = 2.95 mA/M > S Fe(III)P = 1.34 mA/M for H 2 O 2 , and S SWCNT-Fe(III)P = 3.54 mA/M > S Fe(III)P 1.44 mA/M > S SWCNT-OH-Fe(III)P = 0.81 mA/M for NO 2 -

  6. Transient analysis of intercalation electrodes for parameter estimation

    Science.gov (United States)

    Devan, Sheba

    An essential part of integrating batteries as power sources in any application, be it a large scale automotive application or a small scale portable application, is an efficient Battery Management System (BMS). The combination of a battery with the microprocessor based BMS (called "smart battery") helps prolong the life of the battery by operating in the optimal regime and provides accurate information regarding the battery to the end user. The main purposes of BMS are cell protection, monitoring and control, and communication between different components. These purposes are fulfilled by tracking the change in the parameters of the intercalation electrodes in the batteries. Consequently, the functions of the BMS should be prompt, which requires the methodology of extracting the parameters to be efficient in time. The traditional transient techniques applied so far may not be suitable due to reasons such as the inability to apply these techniques when the battery is under operation, long experimental time, etc. The primary aim of this research work is to design a fast, accurate and reliable technique that can be used to extract parameter values of the intercalation electrodes. A methodology based on analysis of the short time response to a sinusoidal input perturbation, in the time domain is demonstrated using a porous electrode model for an intercalation electrode. It is shown that the parameters associated with the interfacial processes occurring in the electrode can be determined rapidly, within a few milliseconds, by measuring the response in the transient region. The short time analysis in the time domain is then extended to a single particle model that involves bulk diffusion in the solid phase in addition to interfacial processes. A systematic procedure for sequential parameter estimation using sensitivity analysis is described. Further, the short time response and the input perturbation are transformed into the frequency domain using Fast Fourier Transform

  7. Dielectric properties of halloysite and halloysite-formamide intercalate

    Energy Technology Data Exchange (ETDEWEB)

    Adamczyk, M., E-mail: mariusz.adamczyk@chem.uni.wroc.pl; Rok, M.; Wolny, A.; Orzechowski, K. [Faculty of Chemistry, University of Wroclaw, Wroclaw 50-383 (Poland)

    2014-01-14

    Due to a high increase in electromagnetic pollution, the protection from non-ionizing electromagnetic radiation (EMR) represents an important problem of contemporary environmental science. We are searching for natural materials with the potential for EMR screening. We have discovered that hydro-halloysite has interesting properties as an EMR absorber. Unfortunately, it is a very unstable material. Drying it for even a short period of time leads to the loss of desired properties. In the paper, we have demonstrated that the intercalation of halloysite (the process of introducing guest molecules into the mineral structure) makes it possible to recover the ability to absorb an electromagnetic wave and obtain a promising material for electromagnetic field shielding applications.

  8. Dielectric properties of halloysite and halloysite-formamide intercalate

    International Nuclear Information System (INIS)

    Adamczyk, M.; Rok, M.; Wolny, A.; Orzechowski, K.

    2014-01-01

    Due to a high increase in electromagnetic pollution, the protection from non-ionizing electromagnetic radiation (EMR) represents an important problem of contemporary environmental science. We are searching for natural materials with the potential for EMR screening. We have discovered that hydro-halloysite has interesting properties as an EMR absorber. Unfortunately, it is a very unstable material. Drying it for even a short period of time leads to the loss of desired properties. In the paper, we have demonstrated that the intercalation of halloysite (the process of introducing guest molecules into the mineral structure) makes it possible to recover the ability to absorb an electromagnetic wave and obtain a promising material for electromagnetic field shielding applications

  9. Design of copper DNA intercalators with leishmanicidal activity.

    Science.gov (United States)

    Navarro, Maribel; Cisneros-Fajardo, Efrén José; Sierralta, Aníbal; Fernández-Mestre, Mercedes; Silva, Pedro; Arrieche, Dwight; Marchán, Edgar

    2003-04-01

    The complexes [Cu(dppz)(NO(3))]NO(3) (1), [Cu(dppz)(2)(NO(3))]NO(3) (2), [Cu(dpq)(NO(3))]NO(3) (3), and [Cu(dpq)(2)(NO(3))]NO(3) (4) were synthesized and characterized by elemental analysis, FAB-mass spectrometry, EPR, UV, and IR spectroscopies, and molar conductivity. DNA interaction studies showed that intercalation is an important way of interacting with DNA for these complexes. The biological activity of these copper complexes was evaluated on Leishmania braziliensis promastigotes, and the results showed leishmanicidal activity. Preliminary ultrastructural studies with the most active complex (2) at 1 h revealed parasite swelling and binucleated cells. This finding suggests that the leishmanicidal activity of the copper complexes could be associated with their interaction with the parasitic DNA.

  10. Thermal decomposition of cesium-ethylene-ternary graphite intercalation compounds

    International Nuclear Information System (INIS)

    Matsumoto, R.; Oishi, Y.; Arii, T.

    2010-01-01

    In this paper, the thermal decomposition of air-stable Cs-ethylene-ternary graphite intercalation compounds (GICs) is discussed. The air stability of Cs-GICs is improved remarkably after the absorption of ethylene into their interlayer nanospace, because the ethylene molecules oligomerize and block the movement of Cs atoms. In addition, the evaporation of Cs atoms from the Cs-ethylene-ternary GICs is observed above 400 o C under a N 2 atmosphere of 100 Pa by ion attachment mass spectrometry. Although the results indicate that Cs-ethylene-ternary GICs remain stable up to approximately 400 o C, their thermal stability is not very high as compared to that of Cs-GICs.

  11. An enhanced hydrogen adsorption enthalpy for fluoride intercalated graphite compounds.

    Science.gov (United States)

    Cheng, Hansong; Sha, Xianwei; Chen, Liang; Cooper, Alan C; Foo, Maw-Lin; Lau, Garret C; Bailey, Wade H; Pez, Guido P

    2009-12-16

    We present a combined theoretical and experimental study on H(2) physisorption in partially fluorinated graphite. This material, first predicted computationally using ab initio molecular dynamics simulation and subsequently synthesized and characterized experimentally, represents a novel class of "acceptor type" graphite intercalated compounds that exhibit significantly higher isosteric heat of adsorption for H(2) at near ambient temperatures than previously demonstrated for commonly available porous carbon-based materials. The unusually strong interaction arises from the semi-ionic nature of the C-F bonds. Although a high H(2) storage capacity (>4 wt %) at room temperature is predicted not to be feasible due to the low heat of adsorption, enhanced storage properties can be envisaged by doping the graphitic host with appropriate species to promote higher levels of charge transfer from graphene to F(-) anions.

  12. Intercalation of vanadate in Ni, Zn layered hydroxyacetates

    International Nuclear Information System (INIS)

    Rojas, Ricardo; Barriga, Cristobalina; Ulibarri, M.A.; Rives, Vicente

    2004-01-01

    Interlayer acetate anions in layered double hydroxyacetates of Ni 2+ and Zn 2+ have been exchanged by oxovanadates following three synthetic routes (at 60 deg. C, under hydrothermal conditions and after preswelling with caprylate anions) and different pH; direct exchange at room temperature was not successful. Complete exchange was achieved under adequated conditions, and the precise nature of the interlayer anion depends on the pH during exchange: at low pH (4.5), the presence of α-VO 3 chains, with anchoring (grafting) of the species to the hydroxide layers, is proposed. At higher pH (9.5) V 2 O 7 4- species are present in the interlayer. Thermal decomposition of these vanadate-intercalated products leads to formation of orthorhombic Ni 2+ and Zn 2+ vanadates, together with NiO

  13. Intercalated radio-chemotherapy in small cell lung cancer

    International Nuclear Information System (INIS)

    Hoskin, P.J.; Parton, D.; Yarnold, J.R.; Cherryman, G.; Smith, I.E.

    1991-01-01

    36 patients with small cell lung cancer have been treated using chemotherapy comprising carboplatin, ifosphamide and etoposide. A total of 6 cycles of chemotherapy was given. In 15 patients with limited disease intercalated radio-chemotherapy was used in which two 5-day courses of hyperfractionated radiotherapy were given to the thorax after the 1st and 2nd cycles of chemotherapy. Each course of thoracic radiotherapy delivered 15 Gy in 15 fractions over 5 days. Oesophagitis occurred in 7 patients (40 percent), in 5 of whom this was severe (WHO grade 3). Radiological pneumonitis developed in 6 patients (40 percent) with subsequent fibrosis in 2 patients. These effects are greater than would be expected with this dose of radiation alone and reflect marked enhancement of normal tissue toxicity. (author). 11 refs.; 1 fig.; 1 tab

  14. Tuning thermal conductivity in molybdenum disulfide by electrochemical intercalation

    Science.gov (United States)

    Zhu, Gaohua; Liu, Jun; Zheng, Qiye; Zhang, Ruigang; Li, Dongyao; Banerjee, Debasish; Cahill, David G.

    2016-01-01

    Thermal conductivity of two-dimensional (2D) materials is of interest for energy storage, nanoelectronics and optoelectronics. Here, we report that the thermal conductivity of molybdenum disulfide can be modified by electrochemical intercalation. We observe distinct behaviour for thin films with vertically aligned basal planes and natural bulk crystals with basal planes aligned parallel to the surface. The thermal conductivity is measured as a function of the degree of lithiation, using time-domain thermoreflectance. The change of thermal conductivity correlates with the lithiation-induced structural and compositional disorder. We further show that the ratio of the in-plane to through-plane thermal conductivity of bulk crystal is enhanced by the disorder. These results suggest that stacking disorder and mixture of phases is an effective mechanism to modify the anisotropic thermal conductivity of 2D materials. PMID:27767030

  15. Phosphate removal from water using lithium intercalated gibbsite.

    Science.gov (United States)

    Wang, Shan-Li; Cheng, Chia-Yi; Tzou, Yu-Min; Liaw, Ren-Bao; Chang, Ta-Wei; Chen, Jen-Hshuan

    2007-08-17

    In this study, lithium intercalated gibbsite (LIG) was investigated for its effectiveness at removing phosphate from water and the mechanisms involved. LIG was prepared through intercalating LiCl into gibbsite giving a structure of [LiAl2(OH)6]+ layers with interlayer Cl- and water. The results of batch adsorption experiments showed that the adsorption isotherms at various pHs exhibited an L-shape and could be fitted well using the Langmuir model. The Langmuir adsorption maximum was determined to be 3.0 mmol g(-1) at pH 4.5 and decreased with increasing pH. The adsorption of phosphate was mainly through the displacement of the interlayer Cl- ions in LIG. In conjunction with the anion exchange reaction, the formation of surface complexes or precipitates could also readily occur at lower pH. The adsorption decreased with increasing pH due to decreased H(2)PO(4)(-)/HPO4(2-) molar ratio in solution and positive charges on the edge faces of LIG. Anion exchange is a fast reaction and can be completed within minutes; on the contrary, surface complexation is a slow process and requires days to reach equilibrium. At lower pH, the amount of adsorbed phosphate decreased significantly as the ionic strength was increased from 0.01 to 0.1M. The adsorption at higher pH showed high selectivity toward divalent HPO4(2-) ions with an increase in ionic strength having no considerable effect on the phosphate adsorption. These results suggest that LIG may be an effective scavenger for removal of phosphate from water.

  16. Advantages of GPU technology in DFT calculations of intercalated graphene

    Science.gov (United States)

    Pešić, J.; Gajić, R.

    2014-09-01

    Over the past few years, the expansion of general-purpose graphic-processing unit (GPGPU) technology has had a great impact on computational science. GPGPU is the utilization of a graphics-processing unit (GPU) to perform calculations in applications usually handled by the central processing unit (CPU). Use of GPGPUs as a way to increase computational power in the material sciences has significantly decreased computational costs in already highly demanding calculations. A level of the acceleration and parallelization depends on the problem itself. Some problems can benefit from GPU acceleration and parallelization, such as the finite-difference time-domain algorithm (FTDT) and density-functional theory (DFT), while others cannot take advantage of these modern technologies. A number of GPU-supported applications had emerged in the past several years (www.nvidia.com/object/gpu-applications.html). Quantum Espresso (QE) is reported as an integrated suite of open source computer codes for electronic-structure calculations and materials modeling at the nano-scale. It is based on DFT, the use of a plane-waves basis and a pseudopotential approach. Since the QE 5.0 version, it has been implemented as a plug-in component for standard QE packages that allows exploiting the capabilities of Nvidia GPU graphic cards (www.qe-forge.org/gf/proj). In this study, we have examined the impact of the usage of GPU acceleration and parallelization on the numerical performance of DFT calculations. Graphene has been attracting attention worldwide and has already shown some remarkable properties. We have studied an intercalated graphene, using the QE package PHonon, which employs GPU. The term ‘intercalation’ refers to a process whereby foreign adatoms are inserted onto a graphene lattice. In addition, by intercalating different atoms between graphene layers, it is possible to tune their physical properties. Our experiments have shown there are benefits from using GPUs, and we reached an

  17. Advantages of GPU technology in DFT calculations of intercalated graphene

    International Nuclear Information System (INIS)

    Pešić, J; Gajić, R

    2014-01-01

    Over the past few years, the expansion of general-purpose graphic-processing unit (GPGPU) technology has had a great impact on computational science. GPGPU is the utilization of a graphics-processing unit (GPU) to perform calculations in applications usually handled by the central processing unit (CPU). Use of GPGPUs as a way to increase computational power in the material sciences has significantly decreased computational costs in already highly demanding calculations. A level of the acceleration and parallelization depends on the problem itself. Some problems can benefit from GPU acceleration and parallelization, such as the finite-difference time-domain algorithm (FTDT) and density-functional theory (DFT), while others cannot take advantage of these modern technologies. A number of GPU-supported applications had emerged in the past several years (www.nvidia.com/object/gpu-applications.html). Quantum Espresso (QE) is reported as an integrated suite of open source computer codes for electronic-structure calculations and materials modeling at the nano-scale. It is based on DFT, the use of a plane-waves basis and a pseudopotential approach. Since the QE 5.0 version, it has been implemented as a plug-in component for standard QE packages that allows exploiting the capabilities of Nvidia GPU graphic cards (www.qe-forge.org/gf/proj). In this study, we have examined the impact of the usage of GPU acceleration and parallelization on the numerical performance of DFT calculations. Graphene has been attracting attention worldwide and has already shown some remarkable properties. We have studied an intercalated graphene, using the QE package PHonon, which employs GPU. The term ‘intercalation’ refers to a process whereby foreign adatoms are inserted onto a graphene lattice. In addition, by intercalating different atoms between graphene layers, it is possible to tune their physical properties. Our experiments have shown there are benefits from using GPUs, and we reached an

  18. Phosphate removal from water using lithium intercalated gibbsite

    International Nuclear Information System (INIS)

    Wang, S.-L.; Cheng, C.-Y.; Tzou, Y.-M.; Liaw, R.-B.; Chang, T.-W.; Chen, J.-H.

    2007-01-01

    In this study, lithium intercalated gibbsite (LIG) was investigated for its effectiveness at removing phosphate from water and the mechanisms involved. LIG was prepared through intercalating LiCl into gibbsite giving a structure of [LiAl 2 (OH) 6 ] + layers with interlayer Cl - and water. The results of batch adsorption experiments showed that the adsorption isotherms at various pHs exhibited an L-shape and could be fitted well using the Langmuir model. The Langmuir adsorption maximum was determined to be 3.0 mmol g -1 at pH 4.5 and decreased with increasing pH. The adsorption of phosphate was mainly through the displacement of the interlayer Cl - ions in LIG. In conjunction with the anion exchange reaction, the formation of surface complexes or precipitates could also readily occur at lower pH. The adsorption decreased with increasing pH due to decreased H 2 PO 4 - /HPO 4 2- molar ratio in solution and positive charges on the edge faces of LIG. Anion exchange is a fast reaction and can be completed within minutes; on the contrary, surface complexation is a slow process and requires days to reach equilibrium. At lower pH, the amount of adsorbed phosphate decreased significantly as the ionic strength was increased from 0.01 to 0.1 M. The adsorption at higher pH showed high selectivity toward divalent HPO 4 2- ions with an increase in ionic strength having no considerable effect on the phosphate adsorption. These results suggest that LIG may be an effective scavenger for removal of phosphate from water

  19. Synthesis and structural characterisation of iron(II) and copper(II) diphosphates containing flattened metal oxotetrahedra

    Energy Technology Data Exchange (ETDEWEB)

    Keates, Adam C. [School of Chemistry, University of Southampton, Southampton, Hampshire SO17 1B,. UK (United Kingdom); Wang, Qianlong [Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY (United Kingdom); Weller, Mark T., E-mail: m.t.weller@bath.ac.uk [Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY (United Kingdom)

    2014-02-15

    Single crystal and bulk polycrystalline forms of K{sub 2}MP{sub 2}O{sub 7} (M=Fe(II), Cu(II)) have been synthesised and their structures determined from single crystal X-ray diffraction data. Both compounds crystallize in the tetragonal system, space group P-42{sub 1}m. Their structures are formed from infinite sheets of linked oxopolyhedra of the stoichiometry [MP{sub 2}O{sub 7}]{sup 2−} with potassium cations situated between the layers. The MO{sub 4} tetrahedra share oxygen atoms with [P{sub 2}O{sub 7}]{sup 4−} diphosphate groups and the potassium ions have KO{sub 8} square prismatic geometry. In both compounds the M(II) centre has an unusual strongly flattened, tetrahedral coordination to oxygen, as a result of the Jahn–Teller (JT) effect for the high spin d{sup 6} Fe(II) and p-orbital mixing or a second order JT effect for d{sup 9} Cu(II) centres in four fold coordination. The uncommon transition metal ion environments found in these materials are reflected in their optical absorption spectra and magnetism data. - Graphical abstract: The structures of the tetragonal polymorphs of K{sub 2}MP{sub 2}O{sub 7}, M=Cu(II), Fe(II), consist of infinite sheets of stoichiometry [MP{sub 2}O{sub 7}]{sup 2−}, formed from linked pyrophosphate groups and MO{sub 4} tetrahedra, separated by potassium ions. In both compounds the unusual tetrahedral coordination of the M(II) centre is strongly flattened as a result of Jahn–Teller (JT) effects for high spin, d{sup 6} Fe(II) and p-orbital mixing and second-order JT effects for d{sup 9} Cu(II). Display Omitted - Highlights: • Tetrahedral copper and iron(II) coordinated by oxygen. • New layered phosphate structure. • Jahn–Teller and d{sup 10} distorted coordinations.

  20. Synthesis and characterization of montmorillonite clay intercalated with molecular magnetic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Marcel G.; Martins, Daniel O.T.A.; Carvalho, Beatriz L.C. de [Instituto de Química, Universidade Federal Fluminense, Niterói, RJ 24.020–150 (Brazil); Mercante, Luiza A. [Laboratório Nacional de Nanotecnologia para o Agronegócio (LNNA), Embrapa Instrumentação, São Carlos, SP 13560 970 (Brazil); Soriano, Stéphane [Instituto de Física, Universidade Federal Fluminense, Niterói, RJ 24.210 346 (Brazil); Andruh, Marius [Inorganic Chemistry Laboratory, Faculty of Chemistry, University of Bucharest, Str. Dumbrava Rosie nr. 23, Bucharest (Romania); Vieira, Méri D., E-mail: gqimeri@vm.uff.br [Instituto de Química, Universidade Federal Fluminense, Niterói, RJ 24.020–150 (Brazil); Vaz, Maria G.F., E-mail: mariavaz@vm.uff.br [Instituto de Química, Universidade Federal Fluminense, Niterói, RJ 24.020–150 (Brazil)

    2015-08-15

    In this work montmorillonite (MMT) clay, whose matrix was modified with an ammonium salt (hexadecyltrimethylammonium bromide – CTAB), was employed as an inorganic host for the intercalation of three different molecular magnetic compounds through ion exchange: a nitronyl nitroxide derivative 2-[4-(N-ethyl)-pyridinium]-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (p-EtRad{sup +}) and two binuclear coordination compounds, [Ni(valpn)Ln]{sup 3+}, where H{sub 2}valpn stands for 1,3-propanediyl-bis(2-iminomethylene-6-methoxy-phenol), and Ln=Gd{sup III}; Dy{sup III}. The pristine MMT and the intercalated materials were characterized by X-ray powder diffraction (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and magnetic measurements. The X-ray diffraction data analysis showed an increase of the interlamellar space of the intercalated MMT, indicating the intercalation of the magnetic compounds. Furthermore, the magnetic properties of the hybrid compounds were investigated, showing similar behavior as the pure magnetic guest species. - Graphical abstract: Montmorillonite clay was employed as inorganic host for the intercalation of three different molecular magnetic compounds through ion exchange - Highlights: • Montmorillonite was employed as a host material. • Three molecular magnetic compounds were intercalated through ion exchange. • The compounds were successful intercalated maintaining the layered structure. • The hybrid materials exhibited similar magnetic behavior as the pure magnetic guest.

  1. An in situ Raman study of the intercalation of supercapacitor-type electrolyte into microcrystalline graphite

    International Nuclear Information System (INIS)

    Hardwick, Laurence J.; Hahn, Matthias; Ruch, Patrick; Holzapfel, Michael; Scheifele, Werner; Buqa, Hilmi; Krumeich, Frank; Novak, Petr; Koetz, Ruediger

    2006-01-01

    An initial Raman study on the effects of intercalation for aprotic electrolyte-based electrochemical double-layer capacitors (EDLCs) is reported. In situ Raman microscopy is employed in the study of the electrochemical intercalation of tetraethylammonium (Et 4 N + ) and tetrafluoroborate (BF 4 - ) into and out of microcrystalline graphite. During cyclic voltammetry experiments, the insertion of Et 4 N + into graphite for the negative electrode occurs at an onset potential of +1.0 V versus Li/Li + . For the positive electrode, BF 4 - was shown to intercalate above +4.3 V versus Li/Li + . The characteristic G-band doublet peak (E 2g2 (i) (1578 cm -1 ) and E 2g2 (b) (1600 cm -1 )) showed that various staged compounds were formed in both cases and the return of the single G-band (1578 cm -1 ) demonstrates that intercalation was fully reversible. The disappearance of the D-band (1329 cm -1 ) in intercalated graphite is also noted and when the intercalant is removed a more intense D-band reappears, indicating possible lattice damage. For cation intercalation, such irreversible changes of the graphite structure are confirmed by scanning electron microscopy (SEM)

  2. High voltage and high specific capacity dual intercalating electrode Li-ion batteries

    Science.gov (United States)

    West, William C. (Inventor); Blanco, Mario (Inventor)

    2010-01-01

    The present invention provides high capacity and high voltage Li-ion batteries that have a carbonaceous cathode and a nonaqueous electrolyte solution comprising LiF salt and an anion receptor that binds the fluoride ion. The batteries can comprise dual intercalating electrode Li ion batteries. Methods of the present invention use a cathode and electrode pair, wherein each of the electrodes reversibly intercalate ions provided by a LiF salt to make a high voltage and high specific capacity dual intercalating electrode Li-ion battery. The present methods and systems provide high-capacity batteries particularly useful in powering devices where minimizing battery mass is important.

  3. Single-layer dispersions of transition metal dichalcogenides in the synthesis of intercalation compounds

    International Nuclear Information System (INIS)

    Golub, Alexander S; Zubavichus, Yan V; Slovokhotov, Yurii L; Novikov, Yurii N

    2003-01-01

    Chemical methods for the exfoliation of transition metal dichalcogenides in a liquid medium to give single-layer dispersions containing quasi-two-dimensional layers of these compounds are surveyed. Data on the structure of dispersions and their use in the synthesis of various types of heterolayered intercalation compounds are discussed and described systematically. Structural features, the electronic structure and the physicochemical properties of the resulting intercalation compounds are considered. The potential of this method of synthesis is compared with that of traditional solid-state methods for the intercalation of layered crystals.

  4. Intercalated vs Non-Intercalated Morphologies in Donor-Acceptor Bulk Heterojunction Solar Cells: PBTTT:Fullerene Charge Generation and Recombination Revisited

    KAUST Repository

    Collado Fregoso, Elisa

    2017-08-04

    In this contribution, we study the role of the donor:acceptor interface nanostructure upon charge separation and recombination in organic photovoltaic devices and blend films, using mixtures of PBTTT and two different fullerene derivatives (PC70BM and ICTA) as models for intercalated and non-intercalated morphologies, respectively. Thermodynamic simulations show that while the completely intercalated system exhibits a large free-energy barrier for charge separation, this barrier is significantly lower in the non-intercalated system, and almost vanishes when energetic disorder is included in the model. Despite these differences, both fs-resolved transient absorption spectroscopy (TAS) and TDCF exhibit extensive first-order losses in that system, suggesting that geminate pairs are the primary product of photoexcitation. In contrast, the system that comprises a combination of fully intercalated polymer:fullerene areas and fullerene aggregated domains (1:4 PBTTT:PC70BM), is the only one that shows slow, second-order recombination of free charges, resulting in devices with an overall higher short circuit current and fill factor. This study therefore provides a novel consideration of the role of the interfacial nanostructure and the nature of bound charges, and their impact upon charge generation and recombination.

  5. Intercalated vs Non-Intercalated Morphologies in Donor-Acceptor Bulk Heterojunction Solar Cells: PBTTT:Fullerene Charge Generation and Recombination Revisited

    KAUST Repository

    Collado Fregoso, Elisa; Hood, Samantha N.; Shoaee, Safa; Schroeder, Bob C.; McCulloch, Iain; Kassal, Ivan; Neher, Dieter; Durrant, James R.

    2017-01-01

    In this contribution, we study the role of the donor:acceptor interface nanostructure upon charge separation and recombination in organic photovoltaic devices and blend films, using mixtures of PBTTT and two different fullerene derivatives (PC70BM and ICTA) as models for intercalated and non-intercalated morphologies, respectively. Thermodynamic simulations show that while the completely intercalated system exhibits a large free-energy barrier for charge separation, this barrier is significantly lower in the non-intercalated system, and almost vanishes when energetic disorder is included in the model. Despite these differences, both fs-resolved transient absorption spectroscopy (TAS) and TDCF exhibit extensive first-order losses in that system, suggesting that geminate pairs are the primary product of photoexcitation. In contrast, the system that comprises a combination of fully intercalated polymer:fullerene areas and fullerene aggregated domains (1:4 PBTTT:PC70BM), is the only one that shows slow, second-order recombination of free charges, resulting in devices with an overall higher short circuit current and fill factor. This study therefore provides a novel consideration of the role of the interfacial nanostructure and the nature of bound charges, and their impact upon charge generation and recombination.

  6. Oxidation of dibenzothiophene as a model substrate for the removal of organic sulphur from fossil fuels by iron(III ions generated from pyrite by Acidithiobacillus ferrooxidans

    Directory of Open Access Journals (Sweden)

    VLADIMIR P. BESKOSKI

    2007-06-01

    Full Text Available Within this paper a new idea for the removal of organically bonded sulphur from fossil fuels is discussed. Dibenzothiophene (DBT was used as a model compound of organicmolecules containing sulphur. This form of (biodesulphurization was performed by an indirect mechanism in which iron(III ions generated from pyrite by Acidithiobacillus ferrooxidans performed the abiotic oxidation. The obtained reaction products, dibenzothiopene sulfoxide and dibenzothiophene sulfone, are more soluble in water than the basic substrate and the obtained results confirmed the basic hypothesis and give the posibility of continuing the experiments related to application of this (biodesulphurization process.

  7. Manganese associated nanoparticles agglomerate of iron(III) oxide: synthesis, characterization and arsenic(III) sorption behavior with mechanism.

    Science.gov (United States)

    Gupta, Kaushik; Maity, Arjun; Ghosh, Uday Chand

    2010-12-15

    Three samples of manganese associated hydrous iron(III) oxide (MNHFO), prepared by incinerating metal hydroxide precipitate at T (± 5)=90, 300 and 600°C, showed increase of crystalline nature in XRD patterns with decreasing As(III) removal percentages. TEM images showed the increase of crystallinity from sample-1 (MNHFO-1) to sample-3 (MNHFO-3). Dimensions (nm) of particles estimated were 5.0, 7.0 and 97.5. Optimization of pH indicated that MNHFO-1 could remove aqueous As(III) efficiently at pH between 3.0 and 7.0. Kinetic and equilibrium data of reactions under the experimental conditions described the pseudo-second order and the Langmuir isotherm equations very well, respectively. The Langmuir capacity (q(m)) estimated was 691.04 mmol kg(-1). The values of enthalpy, Gibb's free energy and entropy changes (ΔH(0)=+23.23 kJ mol(-1), ΔG(0)=-3.43 to -7.20 kJ mol(-1) at T=283-323K, ΔS(0)=+0.094 kJ mol(-1)K(-1)) suggested that the reaction was endothermic, spontaneous and took place with increasing entropy. The As(III) sorbed by MNHFO-1 underwent surface oxidation to As(V), and evidences appeared from the XPS and FTIR investigations. MNHFO-1 packed column (internal diameter: 1.0 cm, height: 3.7 cm) filtered 11.5 dm(3) groundwater (105 μg As dm(-3)) with reducing arsenic concentration to ≤ 10 μg dm(-3). Copyright © 2010 Elsevier B.V. All rights reserved.

  8. Synthesis, characterization and single crystal x-ray analysis of a complex of iron(II) bis(2,4-dimethylphenyl)dithiophosphate with 4-ethylpyridine

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Sandeep; Andotra, Savit; Kaur, Mandeep [University of Jammu, Department of Chemistry (India); Gupta, Vivek K.; Kant, Rajni [Department of Physics and Electronics, University of Jammu, X-ray Crystallographic Laboratory (India); Pandey, Sushil K., E-mail: kpsushil@rediffmail.com [University of Jammu, Department of Chemistry (India)

    2016-09-15

    Complex of iron(II) bis(2,4-dimethylphenyl)dithiophosphate with 4-ethylpyridine [((2,4- (CH{sub 3}){sub 2}C{sub 6}H{sub 3}O)2PS2)2Fe(NC{sub 5}H{sub 4}(C{sub 2}H{sub 5})-4){sub 2}] is synthesized and characterized by elemental analysis, magnetic moment, IR spectroscopy and single crystal X-ray analysis. Complex crystallizes in the monoclinic sp. gr. P2{sub 1}/n, Z = 2. Crystal structure consists of mononuclear units with Fe(II) ion chelated by four S atoms of the two diphenyldithiophosphate ligands in bidentate manner. N atoms from two 4-ethylpyridine ligands are axially coordinated to the Fe(II) atom leading to an octahedral geometry.

  9. Bis(2,3,5,6-tetra-2-pyridylpyrazine-κ3N2,N1,N6iron(II bis(dicyanamidate 4.5-hydrate

    Directory of Open Access Journals (Sweden)

    R. Cortés

    2010-03-01

    Full Text Available In the title compound, [Fe(C24H16N62][N(CN2]2·4.5H2O, the central iron(II ion is hexacoordinated by six N atoms of two tridentate 2,3,5,6-tetra-2-pyridylpyrazine (tppz ligands. Two dicyanamide anions [dca or N(CN2−] act as counter-ions, and 4.5 water molecules act as solvation agents. The structure contains isolated cationic iron(II–tppz complexes and the final neutrality is obtained with the two dicyanamide anions. One of the dicyanamide anions and a water molecule are disordered with an occupancy ratio of 0.614 (8:0.386 (8. O—H...O, O—H...N and C—H...O hydrogen bonds involving dca, water and tppz molecules are observed.

  10. Fabrication of a single layer graphene by copper intercalation on a SiC(0001) surface

    International Nuclear Information System (INIS)

    Yagyu, Kazuma; Tochihara, Hiroshi; Tomokage, Hajime; Suzuki, Takayuki; Tajiri, Takayuki; Kohno, Atsushi; Takahashi, Kazutoshi

    2014-01-01

    Cu atoms deposited on a zero layer graphene grown on a SiC(0001) substrate, intercalate between the zero layer graphene and the SiC substrate after the thermal annealing above 600 °C, forming a Cu-intercalated single layer graphene. On the Cu-intercalated single layer graphene, a graphene lattice with superstructure due to moiré pattern is observed by scanning tunneling microscopy, and specific linear dispersion at the K ¯ point as well as a characteristic peak in a C 1s core level spectrum, which is originated from a free-standing graphene, is confirmed by photoemission spectroscopy. The Cu-intercalated single layer graphene is found to be n-doped

  11. XRD, SEM and infrared study into the intercalation of sodium hexadecyl sulfate (SHS) into hydrocalumite.

    Science.gov (United States)

    Zhang, Ping; Wang, Tianqi; Zhang, Longlong; Wu, Daishe; Frost, Ray L

    2015-12-05

    Hydrocalumite (CaAl-LDH-Cl) interacted with a natural anionic surfactant, sodium hexadecyl sulfate (SHS), was performed using an intercalation method. To understand the intercalation behavior and characterize the resulting products, powder X-ray diffraction (XRD), scan electron microscopy (SEM) and mid-infrared (MIR) spectroscopy combined with near-infrared (NIR) spectroscopy technique were used. The XRD analysis indicated that SHS was intercalated into CaAl-LDH-Cl successfully, resulting in an expansion of the interlayer (from 0.78 nm to 2.74 nm). The bands of C-H stretching vibrations of SHS were observed in the near-infrared spectra, which indicated that the resulting products were indeed CaAl-LDH-SHS. In addition, the bands of water stretching vibrations and OH groups shifted to higher wavenumbers when SHS was intercalated into CaAl-LDH-Cl interlayer space. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Acrylate intercalation and in situ polymerization in iron-, cobalt-, or manganese-substituted nickel hydroxides.

    Science.gov (United States)

    Vaysse, C; Guerlou-Demourgues, L; Duguet, E; Delmas, C

    2003-07-28

    A chimie douce route based on successive redox and exchange reactions has allowed us to prepare new hybrid organic-inorganic materials, composed of polyacrylate macromolecules intercalated into layered double hydroxides (LDHs), deriving from Ni(OH)(2). Monomer intercalation and in situ polymerization mechanisms have appeared to be strongly dependent upon the nature of the substituting cation in the slabs. In the case of iron-based LDHs, a phase containing acrylate monomeric intercalates has been isolated and identified by X-ray diffraction and infrared spectroscopy. Second, interslab free-radical polymerization of acrylate anions has been successfully initiated using potassium persulfate. In cobalt- or manganese-based LDHs, one-step polymerization has been observed, leading directly to a material containing polyacrylate intercalate.

  13. Rechargeable Aqueous Zinc-Ion Battery Based on Porous Framework Zinc Pyrovanadate Intercalation Cathode

    KAUST Repository

    Xia, Chuan; Guo, Jing; Lei, Yongjiu; Liang, Hanfeng; Zhao, Chao; Alshareef, Husam N.

    2017-01-01

    metal pyrovanadate compounds. The zinc pyrovanadate nanowires show significantly improved electrochemical performance when used as intercalation cathode for aqueous zinc–ion battery. Specifically, the ZVO cathode delivers high capacities of 213 and 76 m

  14. Thermal Stability of Modified i-Motif Oligonucleotides with Naphthalimide Intercalating Nucleic Acids

    DEFF Research Database (Denmark)

    El-Sayed, Ahmed Ali; Pedersen, Erik B.; Khaireldin, Nahid Y.

    2016-01-01

    In continuation of our investigation of characteristics and thermodynamic properties of the i-motif 5′-d[(CCCTAA)3CCCT)] upon insertion of intercalating nucleotides into the cytosine-rich oligonucleotide, this article evaluates the stabilities of i-motif oligonucleotides upon insertion of naphtha......In continuation of our investigation of characteristics and thermodynamic properties of the i-motif 5′-d[(CCCTAA)3CCCT)] upon insertion of intercalating nucleotides into the cytosine-rich oligonucleotide, this article evaluates the stabilities of i-motif oligonucleotides upon insertion...... of naphthalimide (1H-benzo[de]isoquinoline-1,3(2H)-dione) as the intercalating nucleic acid. The stabilities of i-motif structures with inserted naphthalimide intercalating nucleotides were studied using UV melting temperatures (Tm) and circular dichroism spectra at different pH values and conditions (crowding...

  15. Intercalation of tartrazine into ZnAl and MgAl layered double hydroxides

    Czech Academy of Sciences Publication Activity Database

    Beneš, L.; Melánová, Klára; Zima, Vítězslav; Svoboda, Jan

    2005-01-01

    Roč. 70, č. 2 (2005), s. 259-267 ISSN 0010-0765 Institutional research plan: CEZ:AV0Z40500505 Keywords : intercalation * hydrotalcite Subject RIV: CA - Inorganic Chemistry Impact factor: 0.949, year: 2005

  16. Removal of lead from aqueous solution on glutamate intercalated layered double hydroxide

    Directory of Open Access Journals (Sweden)

    Shen Yanming

    2017-05-01

    Full Text Available Glutamate intercalated Mg–Al layered double hydroxide (LDH was prepared by co-precipitation and the removal of Pb2+ in the aqueous solution was investigated. The prepared samples were characterized by XRD, FT-IR and SEM. It was shown that glutamate can intercalate into the interlayer space of Mg–Al LDH. The glutamate intercalated Mg–Al LDH can effectively adsorb Pb2+ in the aqueous solution with an adsorption capacity of 68.49 mg g−1. The adsorption of Pb2+ on glutamate intercalated Mg–Al LDH fitted the pseudo-second-order kinetics model and the isotherm can be well defined by Langmuir model.

  17. Effects of Intercalation on the Hole Mobility of Amorphous Semiconducting Polymer Blends

    KAUST Repository

    Cates, Nichole C.; Gysel, Roman; Dahl, Jeremy E. P.; Sellinger, Alan; McGehee, Michael D.

    2010-01-01

    Fullerenes have been shown to intercalate between the side chains of many crystalline and semicrystalline polymers and to affect the properties of polymer:fullerene bulk heterojunction solar cells. Here we present the first in-depth study

  18. A Proteomics Approach to Identify New Putative Cardiac Intercalated Disk Proteins

    NARCIS (Netherlands)

    Soni, Siddarth; Raaijmakers, Antonia J A; Raaijmakers, Linsey M; Damen, J Mirjam A; van Stuijvenberg, Leonie; Vos, Marc A; Heck, Albert J R; van Veen, AAB; Scholten, Arjen

    2016-01-01

    AIMS: Synchronous beating of the heart is dependent on the efficient functioning of the cardiac intercalated disk (ID). The ID is composed of a complex protein network enabling electrical continuity and chemical communication between individual cardiomyocytes. Recently, several different studies

  19. Iron(II) phthalocyanine covalently functionalized graphene as a highly efficient non-precious-metal catalyst for the oxygen reduction reaction in alkaline media

    International Nuclear Information System (INIS)

    Liu, Ying; Wu, Yan-Ying; Lv, Guo-Jun; Pu, Tao; He, Xing-Quan; Cui, Li-Li

    2013-01-01

    Graphical abstract: The fabricated FePc-Gr catalyst for ORR exhibited high activity, favoring a direct 4-electron process, good stability and selectivity, all of which should be attributed to its high conductivity, the synergistic effect between FePc and graphene, as well as the formation of stable FePc-Gr composite through covalent bonding and π–π interaction. - Abstract: A novel iron(II) phthalocyanine covalently modified graphene (FePc-Gr) was synthesized by reduction of the product obtained through an amidation reaction between carboxyl-functionalized graphene oxide (CFGO) and iron(II) tetra-aminophthalocyanine (FeTAPc). The FePc-Gr hybird was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy (RS) and X-ray photoelectron spectroscopy (XPS), respectively. The electrocatalytic properties of FePc-Gr toward the oxygen reduction reaction (ORR) were evaluated using cyclic voltammetry (CV) and linear sweep voltammetry methods. The peak potential of the ORR on the FePc-Gr catalyst was found to be about −0.12 V vs. SCE in 0.1 M NaOH solution, which was 180 and 360 mV more positive than that on FeTAPc and bare GCE, respectively. The rotating disk electrode (RDE) and rotating ring disk electrode (RRDE) measurements revealed that the ORR mechanism was nearly via a direct four-electron pathway to water on FePc-Gr. The current still remained 83.5% of its initial after chronoamperometric test for 10,000 s. Nevertheless, Pt/C catalyst only retained 40.5% of its initial current. The peak potential and peak current changed slightly when 3 M methanol was introduced. So the FePc-Gr composite catalyst for ORR exhibited high activity, good stability and methanol-tolerance, which could be used as a promising Pt-free catalyst for ORR in alkaline direct methanol fuel cell (DMFC)

  20. An intercalated BSc degree is associated with higher marks in subsequent medical school examinations

    OpenAIRE

    Cleland, Jennifer A; Milne, Andrew; Sinclair, Hazel; Lee, Amanda J

    2009-01-01

    Abstract Background To compare medical students on a modern MBChB programme who did an optional intercalated degree with their peers who did not intercalate; in particular, to monitor performance in subsequent undergraduate degree exams. Methods This was a retrospective, observational study of anonymised databases of medical student assessment outcomes. Data were accessed for graduates, University of Aberdeen Medical School, Scotland, UK, from the years 2003 to 2007 (n = 861). The main outcom...

  1. Iron Intercalation in Covalent-Organic Frameworks: A Promising Approach for Semiconductors

    OpenAIRE

    Pakhira, Srimanta; Lucht, Kevin P.; Mendoza-Cortes, Jose L.

    2017-01-01

    Covalent-organic frameworks (COFs) are intriguing platforms for designing functional molecular materials. Here, we present a computational study based on van der Waals dispersion-corrected hybrid density functional theory (DFT-D) to design boroxine-linked and triazine-linked COFs intercalated with Fe. Keeping the original $P-6m2$ symmetry of the pristine COF (COF-Fe-0), we have computationally designed seven new COFs by intercalating Fe atoms between two organic layers. The equilibrium struct...

  2. Self-consistent electronic structure of a model stage-1 graphite acceptor intercalate

    International Nuclear Information System (INIS)

    Campagnoli, G.; Tosatti, E.

    1981-04-01

    A simple but self-consistent LCAO scheme is used to study the π-electronic structure of an idealized stage-1 ordered graphite acceptor intercalate, modeled approximately on C 8 AsF 5 . The resulting non-uniform charge population within the carbon plane, band structure, optical and energy loss properties are discussed and compared with available spectroscopic evidence. The calculated total energy is used to estimate migration energy barriers, and the intercalate vibration mode frequency. (author)

  3. Bifunctional Rhodium Intercalator Conjugates as Mismatch-Directing DNA Alkylating Agents

    OpenAIRE

    Schatzschneider, Ulrich; Barton, Jacqueline K.

    2004-01-01

    A conjugate of a DNA mismatch-specific rhodium intercalator, containing the bulky chrysenediimine ligand, and an aniline mustard has been prepared, and targeting of mismatches in DNA by this conjugate has been examined. The preferential alkylation of mismatched over fully matched DNA is found by a mobility shift assay at concentrations where untethered organic mustards show little reaction. The binding site of the Rh intercalator was determined by DNA photocleavage, and the position of covale...

  4. Evolution of interfacial intercalation chemistry on epitaxial graphene/SiC by surface enhanced Raman spectroscopy

    International Nuclear Information System (INIS)

    Ferralis, Nicola; Carraro, Carlo

    2014-01-01

    Highlights: • H-intercalated epitaxial graphene–SiC interface studied with surface enhanced Raman. • Evolution of graphene and H–Si interface with UV-ozone, annealing and O-exposure. • H–Si interface and quasi-freestanding graphene are retained after UV-ozone treatment. • Enhanced ozonolytic reactivity at the edges of H-intercalated defected graphene. • Novel SERS method for characterizing near-surface graphene–substrate interfaces. - Abstract: A rapid and facile evaluation of the effects of physical and chemical processes on the interfacial layer between epitaxial graphene monolayers on SiC(0 0 0 1) surfaces is essential for applications in electronics, photonics, and optoelectronics. Here, the evolution of the atomic scale epitaxial graphene-buffer-layer–SiC interface through hydrogen intercalation, thermal annealings, UV-ozone etching and oxygen exposure is studied by means of single microparticle mediated surface enhanced Raman spectroscopy (smSERS). The evolution of the interfacial chemistry in the buffer layer is monitored through the Raman band at 2132 cm −1 corresponding to the Si-H stretch mode. Graphene quality is monitored directly by the selectively enhanced Raman signal of graphene compared to the SiC substrate signal. Through smSERS, a simultaneous correlation between optimized hydrogen intercalation in epitaxial graphene/SiC and an increase in graphene quality is uncovered. Following UV-ozone treatment, a fully hydrogen passivated interface is retained, while a moderate degradation in the quality of the hydrogen intercalated quasi-freestanding graphene is observed. While hydrogen intercalated defect free quasi-freestanding graphene is expected to be robust upon UV-ozone, thermal annealing, and oxygen exposure, ozonolytic reactivity at the edges of H-intercalated defected graphene results in enhanced amorphization of the quasi-freestanding (compared to non-intercalated) graphene, leading ultimately to its complete etching

  5. Hydroxy double salts loaded with bioactive ions: Synthesis, intercalation mechanisms, and functional performance

    International Nuclear Information System (INIS)

    Kaassis, Abdessamad Y.A.; Xu, Si-Min; Guan, Shanyue; Evans, David G.; Wei, Min; Williams, Gareth R.

    2016-01-01

    The intercalation of the anions of diclofenac (Dic), naproxen (Nap), and valproic acid (Val) into three hydroxy double salts (HDSs) has been explored in this work. Experiments were performed with [Co 1.2 Zn 3.8 (OH) 8 ](NO 3 ) 2 ·2H 2 O (CoZn-NO 3 ), [Ni 2 Zn 3 (OH) 8 ](NO 3 ) 2 ·2H 2 O (NiZn-NO 3 ) and [Zn 5 (OH) 8 ](NO 3 ) 2 ·2H 2 O (Zn-NO 3 ). It proved possible to intercalate diclofenac and naproxen into all three HDSs. In contrast, Val could be intercalated into CoZn-NO 3 but when it was reacted with Zn-NO 3 the HDS structure was destroyed, and the product comprised ZnO. Successful intercalation was verified by X-ray diffraction, IR spectroscopy, and elemental microanalysis. Molecular dynamics simulations showed the Dic and Nap ions to arrange themselves in an “X” shape in the interlayer space, forming a bilayer. Val was found to adopt a position with its aliphatic groups parallel to the HDS layer, again in a bilayer. In situ time resolved X-ray diffraction experiments revealed that intercalation of Dic and Nap into CoZn-NO 3 and Zn-NO 3 is mechanistically complex, with a number of intermediate phases observed. In contrast, the intercalation of all three guests into NiZn-NO 3 and of Val into CoZn-NO 3 are simple one step reactions proceeding directly from the starting material to the product. The HDS-drug composites were found to have sustained release profiles. - Graphical abstract: Seven new drug intercalates of hydroxy double salts (HDSs) have been prepared and characterised. The intercalation mechanisms have been explored, and the drug release properties of the HDS/drug composites quantified. Display Omitted

  6. Evolution of interfacial intercalation chemistry on epitaxial graphene/SiC by surface enhanced Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ferralis, Nicola, E-mail: ferralis@mit.edu [Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Carraro, Carlo [Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720 (United States)

    2014-11-30

    Highlights: • H-intercalated epitaxial graphene–SiC interface studied with surface enhanced Raman. • Evolution of graphene and H–Si interface with UV-ozone, annealing and O-exposure. • H–Si interface and quasi-freestanding graphene are retained after UV-ozone treatment. • Enhanced ozonolytic reactivity at the edges of H-intercalated defected graphene. • Novel SERS method for characterizing near-surface graphene–substrate interfaces. - Abstract: A rapid and facile evaluation of the effects of physical and chemical processes on the interfacial layer between epitaxial graphene monolayers on SiC(0 0 0 1) surfaces is essential for applications in electronics, photonics, and optoelectronics. Here, the evolution of the atomic scale epitaxial graphene-buffer-layer–SiC interface through hydrogen intercalation, thermal annealings, UV-ozone etching and oxygen exposure is studied by means of single microparticle mediated surface enhanced Raman spectroscopy (smSERS). The evolution of the interfacial chemistry in the buffer layer is monitored through the Raman band at 2132 cm{sup −1} corresponding to the Si-H stretch mode. Graphene quality is monitored directly by the selectively enhanced Raman signal of graphene compared to the SiC substrate signal. Through smSERS, a simultaneous correlation between optimized hydrogen intercalation in epitaxial graphene/SiC and an increase in graphene quality is uncovered. Following UV-ozone treatment, a fully hydrogen passivated interface is retained, while a moderate degradation in the quality of the hydrogen intercalated quasi-freestanding graphene is observed. While hydrogen intercalated defect free quasi-freestanding graphene is expected to be robust upon UV-ozone, thermal annealing, and oxygen exposure, ozonolytic reactivity at the edges of H-intercalated defected graphene results in enhanced amorphization of the quasi-freestanding (compared to non-intercalated) graphene, leading ultimately to its complete etching.

  7. Facile synthesis of deoxycholate intercalated layered double hydroxide nanohybrids via a coassembly process

    International Nuclear Information System (INIS)

    Wu, Xiaowen; Wang, Shuang; Du, Na; Zhang, Renjie; Hou, Wanguo

    2013-01-01

    In this paper, we describe a synthesis strategy of deoxycholate (DC) intercalated layered double hydroxide (LDH) nanohybrids via a coassembly method at room temperature. For this strategy, LDH particles were delaminated to well-dispersed 2D nanosheets in formamide, and the resulting LDH nanosheets were then coassembled with DC anions into the DC intercalated LDH (DC-LDH) nanohybrids. The so-synthesized nanohybrids were characterized by XRD, TEM, FT-IR, elemental analyses and TG-DSC. It was found that the loading amount of DC in the nanohybrids could be easily controlled by changing the ratio of DC to LDH. In addition, the nanohybrids have similar characteristics with the DC-LDH nanohybrids synthesized by the hydrothermal method, including their DC loading, crystal structure, morphology and thermal gravimetric behavior. However, this strategy exhibited the advantages of short reaction time and mild experimental conditions compared with the hydrothermal method. - Graphical abstract: Deoxycholate intercalated layered double hydroxide nanohybrids were successfully synthesized via a coassembly strategy. In this strategy, the interlayer spaces of LDHs can be efficiently used for the intercalation of guest species. - Highlights: • Deoxycholate intercalated layered double hydroxide nanohybrids were synthesized via a coassembly strategy. • This strategy exhibited the advantages of short time and mild conditions. • This strategy can enable organic species to be readily intercalated into the LDH galleries

  8. An intercalated BSc degree is associated with higher marks in subsequent medical school examinations

    Directory of Open Access Journals (Sweden)

    Sinclair Hazel

    2009-05-01

    Full Text Available Abstract Background To compare medical students on a modern MBChB programme who did an optional intercalated degree with their peers who did not intercalate; in particular, to monitor performance in subsequent undergraduate degree exams. Methods This was a retrospective, observational study of anonymised databases of medical student assessment outcomes. Data were accessed for graduates, University of Aberdeen Medical School, Scotland, UK, from the years 2003 to 2007 (n = 861. The main outcome measure was marks for summative degree assessments taken after intercalating. Results Of 861 medical students, 154 (17.9% students did an intercalated degree. After adjustment for cohort, maturity, gender and baseline (3rd year performance in matching exam type, having done an IC degree was significantly associated with attaining high (18–20 common assessment scale (CAS marks in three of the six degree assessments occurring after the IC students rejoined the course: the 4th year written exam (p th year OSCE (p = 0.001 and the 5th year Elective project (p = 0.010. Conclusion Intercalating was associated with improved performance in Years 4 and 5 of the MBChB. This improved performance will further contribute to higher academic ranking for Foundation Year posts. Long-term follow-up is required to identify if doing an optional intercalated degree as part of a modern medical degree is associated with following a career in academic medicine.

  9. Study on intercalation of ionic liquid into montmorillonite and its property evaluation

    International Nuclear Information System (INIS)

    Takahashi, Chisato; Shirai, Takashi; Fuji, Masayoshi

    2012-01-01

    Present study report fabrication of a solid–liquid intercalated compound using montmorillonite and ionic liquid [IL; 1-Butyl-3-methylimidazolium tetrafluoroborate; ([BMIM][BF 4 ])]. The intercalation of IL into the interlayer of montmorillonite was revealed by swelling behavior measured by X-ray diffraction (XRD) and cation exchange capacity (CEC). The crystal swelling structure of intercalation compound was further evidenced by transmission electron microscope (TEM). From these results, the arrangement of [BMIM] + ions (cationic part of IL) into the unit layer were proposed. Furthermore, the montmorillonite showed electrical conductivity with the aid of IL. This demonstrates a successful attempt to fabricate a solid–liquid state nano-structure compound as possible transparent electrically conducting thin film. -- Highlights: ► Direct intercalation of ionic liquid into the montmorillonite was studied. ► The crystal swelling structure in liquid state was successfully characterized by TEM. ► We proposed the atomic arrangement of intercalated compound using ionic liquid. ► Ionic liquid is useful for fabricating an intercalated compound with electrical-conductivity.

  10. Critical role of DNA intercalation in enzyme-catalyzed nucleotide flipping

    Science.gov (United States)

    Hendershot, Jenna M.; O'Brien, Patrick J.

    2014-01-01

    Nucleotide flipping is a common feature of DNA-modifying enzymes that allows access to target sites within duplex DNA. Structural studies have identified many intercalating amino acid side chains in a wide variety of enzymes, but the functional contribution of these intercalating residues is poorly understood. We used site-directed mutagenesis and transient kinetic approaches to dissect the energetic contribution of intercalation for human alkyladenine DNA glycosylase, an enzyme that initiates repair of alkylation damage. When AAG flips out a damaged nucleotide, the void in the duplex is filled by a conserved tyrosine (Y162). We find that tyrosine intercalation confers 140-fold stabilization of the extrahelical specific recognition complex, and that Y162 functions as a plug to slow the rate of unflipping by 6000-fold relative to the Y162A mutant. Surprisingly, mutation to the smaller alanine side chain increases the rate of nucleotide flipping by 50-fold relative to the wild-type enzyme. This provides evidence against the popular model that DNA intercalation accelerates nucleotide flipping. In the case of AAG, DNA intercalation contributes to the specific binding of a damaged nucleotide, but this enhanced specificity comes at the cost of reduced speed of nucleotide flipping. PMID:25324304

  11. Quasi-Free-Standing Graphene Monolayer on a Ni Crystal through Spontaneous Na Intercalation

    Directory of Open Access Journals (Sweden)

    Young S. Park

    2014-07-01

    Full Text Available Graphene on metal substrates often shows different electronic properties from isolated graphene because of graphene-substrate interactions. One needs to remove the metals with acids and then to transfer graphene to weakly interacting substrates to recover electrical properties inherent in graphene. This process is not easy and besides causes undesirable tears, defects, and impurities in graphene. Here, we report a method to recover the electronic structure of graphene from a strongly interacting Ni substrate by spontaneous Na intercalation. In order to characterize the intercalation process, the density-functional-theory calculations and angle-resolved photoemission-spectroscopy (ARPES and scanning-tunneling-microscopy (STM measurements are carried out. From the density-functional-theory calculations, Na atoms energetically prefer interface intercalation to surface adsorption for the graphene/Ni(111 surface. Unlike most intercalants, Na atoms intercalate spontaneously at room temperature due to a tiny diffusion barrier, which is consistent with our temperature-dependent ARPES and core-level photoemission spectroscopy, and with our submonolayer ARPES and STM results at room temperature. As a result of the spontaneous intercalation, the electronic structure of graphene is almost recovered, as confirmed by the Dirac cone with a negligible band gap in ARPES and the sixfold symmetry in STM.

  12. A rechargeable iodine-carbon battery that exploits ion intercalation and iodine redox chemistry.

    Science.gov (United States)

    Lu, Ke; Hu, Ziyu; Ma, Jizhen; Ma, Houyi; Dai, Liming; Zhang, Jintao

    2017-09-13

    Graphitic carbons have been used as conductive supports for developing rechargeable batteries. However, the classic ion intercalation in graphitic carbon has yet to be coupled with extrinsic redox reactions to develop rechargeable batteries. Herein, we demonstrate the preparation of a free-standing, flexible nitrogen and phosphorus co-doped hierarchically porous graphitic carbon for iodine loading by pyrolysis of polyaniline coated cellulose wiper. We find that heteroatoms could provide additional defect sites for encapsulating iodine while the porous carbon skeleton facilitates redox reactions of iodine and ion intercalation. The combination of ion intercalation with redox reactions of iodine allows for developing rechargeable iodine-carbon batteries free from the unsafe lithium/sodium metals, and hence eliminates the long-standing safety issue. The unique architecture of the hierarchically porous graphitic carbon with heteroatom doping not only provides suitable spaces for both iodine encapsulation and cation intercalation but also generates efficient electronic and ionic transport pathways, thus leading to enhanced performance.Carbon-based electrodes able to intercalate Li + and Na + ions have been exploited for high performing energy storage devices. Here, the authors combine the ion intercalation properties of porous graphitic carbons with the redox chemistry of iodine to produce iodine-carbon batteries with high reversible capacities.

  13. Optical properties of NbCl5 and ZnMg intercalated graphite compounds

    International Nuclear Information System (INIS)

    Jung, Eilho; Lee, Seokbae; Roh, Seulki; Kang, Jihoon; Park, Tuson; Hwang, Jungseek; Meng, Xiuqing; Tongay, Sefaattin

    2014-01-01

    We studied NbCl 5 and ZnMg alloy intercalated graphite compounds using an optical spectroscopy technique. These intercalated metallic graphite samples were quite challenging to obtain optical reflectance spectra since they were not flat and quite thin. By using both a new method and an in situ gold evaporation technique we were able to obtain reliable reflectance spectra of our samples in the far and mid infrared range (80–7000 cm −1 ). We extracted the optical constants including the optical conductivity and the dielectric function from the measured reflectance spectra using a Kramers–Kronig analysis. We also extracted the dc conductivity and the plasma frequencies from the optical conductivity and dielectric functions. NbCl 5 intercalated graphite samples show similar optical conductivity spectra as bare highly oriented pyrolytic graphite even though there are some differences in detail. ZnMg intercalated samples show significantly different optical conductivity spectra from the bare graphite. Optical spectroscopy is one of the most reliable experimental techniques to obtain the electronic band structures of materials. The obtained optical conductivities support the recent theoretically calculated electronic band structures of NbCl 5 and ZnMg intercalated graphite compounds. Our results also provide important information of electronic structures and charge carrier properties of these two new intercalated materials for applications. (paper)

  14. Solid-state chelation of metal ions by ethylenediaminetetraacetate intercalated in a layered double hydroxide.

    Science.gov (United States)

    Tarasov, Konstantin A; O'Hare, Dermot; Isupov, Vitaly P

    2003-03-24

    The solid-state chelation of transition metal ions (Co(2+), Ni(2+), and Cu(2+)) from aqueous solutions into the lithium aluminum layered double hydroxide ([LiAl(2)(OH)(6)]Cl x 0.5H(2)O or LDH) which has been pre-intercalated with EDTA (ethylenediaminetetraacetate) ligand has been investigated. The intercalated metal cations form [M(edta)](2)(-) complexes between the LDH layers as indicated by elemental analysis, powder X-ray diffraction, and IR and UV-vis spectroscopies. If metal chloride or nitrate salts are used in the reaction with the LDH then co-intercalation of either the Cl(-) or NO(3)(-) anions is observed. In the case of metal acetate salts the cations intercalate without the accompanying anion. This can be explained by the different intercalation selectivity of the anions in relation to the LDH. In the latter case the introduction of the positive charge into LDH structure was compensated for by the release from the solid of the equivalent quantity of lithium and hydrogen cations. Time-resolved in-situ X-ray diffraction measurements have revealed that the chelation/intercalation reactions proceed very quickly. The rate of the reaction found for nickel acetate depends on concentration as approximately k[Ni(Ac)(2)](3).

  15. Mechanochemical synthesis and intercalation of Ca(II)Fe(III)-layered double hydroxides

    Energy Technology Data Exchange (ETDEWEB)

    Ferencz, Zs.; Szabados, M.; Varga, G.; Csendes, Z. [Department of Organic Chemistry, University of Szeged, Dóm tér 8, Szeged H-6720 (Hungary); Materials and Solution Structure Research Group, Institute of Chemistry, University of Szeged, Aradi Vértanúk tere 1, Szeged H-6720 (Hungary); Kukovecz, Á. [Department of Applied and Environmental Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720 (Hungary); MTA-SZTE “Lendület” Porous Nanocomposites Research Group, Rerrich Béla tér 1, Szeged H-6720 (Hungary); Kónya, Z. [Department of Applied and Environmental Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720 (Hungary); MTA-SZTE Reaction Kinetics and Surface Chemistry Research Group, Rerrich Béla tér 1, Szeged H-6720 (Hungary); Carlson, S. [MAX IV Laboratory, Ole Römers väg 1, Lund SE-223 63 (Sweden); Sipos, P. [Materials and Solution Structure Research Group, Institute of Chemistry, University of Szeged, Aradi Vértanúk tere 1, Szeged H-6720 (Hungary); Department of Inorganic and Analytical Chemistry, University of Szeged, Dóm tér 7, Szeged H-6720 (Hungary); and others

    2016-01-15

    A mechanochemical method (grinding the components without added water – dry grinding, followed by further grinding in the presence of minute amount of water or NaOH solution – wet grinding) was used in this work for the preparation and intercalation of CaFe-layered double hydroxides (LDHs). Both the pristine LDHs and the amino acid anion (cystinate and tyrosinate) intercalated varieties were prepared by the two-step grinding procedure in a mixer mill. By systematically changing the conditions of the preparation method, a set of parameters could be determined, which led to the formation of close to phase-pure LDH. The optimisation procedure was also applied for the intercalation processes of the amino acid anions. The resulting materials were structurally characterised by a range of methods (X-ray diffractometry, scanning electron microscopy, energy dispersive analysis, thermogravimetry, X-ray absorption and infra-red spectroscopies). It was proven that this simple mechanochemical procedure was able to produce complex organic–inorganic nanocomposites: LDHs intercalated with amino acid anions. - Graphical abstract: Amino acid anion-Ca(II)Fe(III)-LDHs were successfully prepared by a two-step milling procedure. - Highlights: • Synthesis of pristine and amino acid intercalated CaFe-LDHs by two-step milling. • Identifying the optimum synthesis and intercalation parameters. • Characterisation of the samples with a range of instrumental methods.

  16. Oxidative degradation of the organometallic iron(II) complex [Fe{bis[3-(pyridin-2-yl)-1H-imidazol-1-yl]methane}(MeCN)(PMe3)](PF6)2: structure of the ligand decomposition product trapped via coordination to iron(II).

    Science.gov (United States)

    Haslinger, Stefan; Pöthig, Alexander; Cokoja, Mirza; Kühn, Fritz E

    2015-12-01

    Iron is of interest as a catalyst because of its established use in the Haber-Bosch process and because of its high abundance and low toxicity. Nitrogen-heterocyclic carbenes (NHC) are important ligands in homogeneous catalysis and iron-NHC complexes have attracted increasing attention in recent years but still face problems in terms of stability under oxidative conditions. The structure of the iron(II) complex [1,1'-bis(pyridin-2-yl)-2,2-bi(1H-imidazole)-κN(3)][3,3'-bis(pyridin-2-yl-κN)-1,1'-methanediylbi(1H-imidazol-2-yl-κC(2))](trimethylphosphane-κP)iron(II) bis(hexafluoridophosphate), [Fe(C17H14N6)(C16H12N6)(C3H9P)](PF6)2, features coordination by an organic decomposition product of a tetradentate NHC ligand in an axial position. The decomposition product, a C-C-coupled biimidazole, is trapped by coordination to still-intact iron(II) complexes. Insights into the structural features of the organic decomposition products might help to improve the stability of oxidation catalysts under harsh conditions.

  17. Spectroscopic, potentiometric and theoretical studies on the binding properties of a novel tripodal polycatechol-imine ligand towards iron(III)

    Science.gov (United States)

    Kanungo, B. K.; Sahoo, Suban K.; Baral, Minati

    2008-12-01

    A novel multidentate tripodal ligand, cis, cis-1,3,5-tris[(2,3-dihydroxybenzylidene)aminomethyl]cyclohexane (TDBAC, L) containing one catechol unit in each arms of a tripodal amine, cis, cis-1,3,5-tris(aminomethyl)cyclohexane was investigated as a chelator for iron(III) through potentiometric and spectrophotometric methods in an aqueous medium of 0.1N ionic strength and 25 ± 1 °C as well as in ethanol by continuous variation method. From pH metric in water, three protonation constants characterized for the three-hydroxyl groups of the catechol units at ortho were used as input data to evaluate the stability constants of the complexes. Formation of monomeric complexes FeLH 3, FeLH 2, FeLH and FeL were depicted. In ethanol, formation of complexes FeL, Fe 2L and Fe 3L were characterized. Structures of the complexes were explained by using the experimental evidences and predicted through molecular modeling calculations. The ligand showed potential to coordinate iron(III) through three imine nitrogens and three catecholic oxygens at ortho to form a tris(iminocatecholate) type complex.

  18. Coumarin-Based Fluorescent Probes for Dual Recognition of Copper(II and Iron(III Ions and Their Application in Bio-Imaging

    Directory of Open Access Journals (Sweden)

    Olimpo García-Beltrán

    2014-01-01

    Full Text Available Two new coumarin-based “turn-off” fluorescent probes, (E-3-((3,4-dihydroxybenzylideneamino-7-hydroxy-2H-chromen-2-one (BS1 and (E-3-((2,4-dihydroxybenzylideneamino-7-hydroxy-2H-chromen-2-one (BS2, were synthesized and their detection of copper(II and iron(III ions was studied. Results show that both compounds are highly selective for Cu2+ and Fe3+ ions over other metal ions. However, BS2 is detected directly, while detection of BS1 involves a hydrolysis reaction to regenerate 3-amino-7-hydroxycoumarin (3 and 3,4-dihydroxybenzaldehyde, of which 3 is able to react with copper(II or iron(III ions. The interaction between the tested compounds and copper or iron ions is associated with a large fluorescence decrease, showing detection limits of ca. 10−5 M. Preliminary studies employing epifluorescence microscopy demonstrate that Cu2+ and Fe3+ ions can be imaged in human neuroblastoma SH-SY5Y cells treated with the tested probes.

  19. Liquid-like thermal conduction in intercalated layered crystalline solids

    Science.gov (United States)

    Li, B.; Wang, H.; Kawakita, Y.; Zhang, Q.; Feygenson, M.; Yu, H. L.; Wu, D.; Ohara, K.; Kikuchi, T.; Shibata, K.; Yamada, T.; Ning, X. K.; Chen, Y.; He, J. Q.; Vaknin, D.; Wu, R. Q.; Nakajima, K.; Kanatzidis, M. G.

    2018-03-01

    As a generic property, all substances transfer heat through microscopic collisions of constituent particles1. A solid conducts heat through both transverse and longitudinal acoustic phonons, but a liquid employs only longitudinal vibrations2,3. As a result, a solid is usually thermally more conductive than a liquid. In canonical viewpoints, such a difference also serves as the dynamic signature distinguishing a solid from a liquid. Here, we report liquid-like thermal conduction observed in the crystalline AgCrSe2. The transverse acoustic phonons are completely suppressed by the ultrafast dynamic disorder while the longitudinal acoustic phonons are strongly scattered but survive, and are thus responsible for the intrinsically ultralow thermal conductivity. This scenario is applicable to a wide variety of layered compounds with heavy intercalants in the van der Waals gaps, manifesting a broad implication on suppressing thermal conduction. These microscopic insights might reshape the fundamental understanding on thermal transport properties of matter and open up a general opportunity to optimize performances of thermoelectrics.

  20. Low cost iodine intercalated graphene for fuel cells electrodes

    Science.gov (United States)

    Marinoiu, Adriana; Raceanu, Mircea; Carcadea, Elena; Varlam, Mihai; Stefanescu, Ioan

    2017-12-01

    On the theoretical predictions, we report the synthesis of iodine intercalated graphene for proton exchange membrane fuel cells (PEMFCs) applications. The structure and morphology of the samples were characterized by X-ray photoelectron spectroscopy (XPS) analysis, specific surface area by BET method, Raman investigations. The presence of elemental iodine in the form of triiodide and pentaiodide was validated, suggesting that iodine was trapped between graphene layers, leading to interactions with C atoms. The electrochemical performances of iodinated graphenes were tested and compared with a typical PEMFC configuration, containing different Pt/C loading (0.4 and 0.2 mg cm-2). If iodinated graphene is included as microporous layer, the electrochemical performances of the fuel cell are higher in terms of power density than the typical fuel cell. Iodine-doped graphenes have been successfully obtained by simple and cost effective synthetic strategy and demonstrated new insights for designing of a high performance metal-free ORR catalyst by a scalable technique.

  1. Manganese oxide electrode with excellent electrochemical performance for sodium ion batteries by pre-intercalation of K and Na ions.

    Science.gov (United States)

    Feng, Mengya; Du, Qinghua; Su, Li; Zhang, Guowei; Wang, Guiling; Ma, Zhipeng; Gao, Weimin; Qin, Xiujuan; Shao, Guangjie

    2017-05-22

    Materials with a layered structure have attracted tremendous attention because of their unique properties. The ultrathin nanosheet structure can result in extremely rapid intercalation/de-intercalation of Na ions in the charge-discharge progress. Herein, we report a manganese oxide with pre-intercalated K and Na ions and having flower-like ultrathin layered structure, which was synthesized by a facile but efficient hydrothermal method under mild condition. The pre-intercalation of Na and K ions facilitates the access of electrolyte ions and shortens the ion diffusion pathways. The layered manganese oxide shows ultrahigh specific capacity when it is used as cathode material for sodium-ion batteries. It also exhibits excellent stability and reversibility. It was found that the amount of intercalated Na ions is approximately 71% of the total charge. The prominent electrochemical performance of the manganese oxide demonstrates the importance of design and synthesis of pre-intercalated ultrathin layered materials.

  2. Intercalation of iron hexacyano complexes in Zn,Al hydrotalcite. Part 2. A mid-infrared and Raman spectroscopic study

    International Nuclear Information System (INIS)

    Kloprogge, J.T.; Weier, Matt; Crespo, Inmaculada; Ulibarri, M.A.; Barriga, Cristobalina; Rives, V.; Martens, W.N.; Frost, R.L.

    2004-01-01

    Combined mid-IR and Raman spectroscopies indicate that intercalation of hexacyanoferrate (II) and (III) in the interlayer space of a Zn,Al hydrotalcite dried at 60 deg. C leads to layered solids where the intercalated species correspond to both hexacyanoferrate(II) and (III). This is an indication that depending on the oxidation state of the initial hexacyanoferrate, partial oxidation and reduction takes place upon intercalation. The symmetry of the intercalated hexacyanoferrate decreases from O h existing in the free anions to D 3d . The observation of a broad band around 2080 cm -1 is indicative of the removal of cyanide from the intercalation complex to the outside surface of the crystals. Its position in the intercalation complex is probably filled by a hydroxyl group

  3. Intercalation of alcohols into barium phenylphosphonate: Influence of the number and position of funcitonal groups in the guests on their arrangement in the intercalates.

    Czech Academy of Sciences Publication Activity Database

    Melánová, Klára; Beneš, L.; Zima, Vítězslav; Svoboda, J.; Růžička, A.

    2017-01-01

    Roč. 251, July (2017), s. 211-216 ISSN 0022-4596 R&D Projects: GA ČR(CZ) GA14-13368S Institutional support: RVO:61389013 Keywords : intercalation * barium phosphonate * alcohol s Subject RIV: CA - Inorganic Chemistry OBOR OECD: Inorganic and nuclear chemistry Impact factor: 2.299, year: 2016

  4. Resistivity features in intercalated graphite compounds with bromine and iodine chloride in the region of structural phase transitions in the layer of intercalate

    International Nuclear Information System (INIS)

    Ovsyijenko, Yi.V.; Lazarenko, O.A.; Matsuj, L.Yu.; Prokopov, O.Yi.

    2013-01-01

    In the paper anomalous changes of resistivity in graphite intercalated compounds with iodine chloride and bromine are investigated in the phase transition temperature interval. It is shown that these anomalies are caused by the change of carriers mobility in the phase transitional interval as well as by the origin of ''mobile ions liquids''

  5. Metallization and stiffness of the Li-intercalated MoS{sub 2} bilayer

    Energy Technology Data Exchange (ETDEWEB)

    Petrova, N.V. [Institute of Physics of National Academy of Sciences of Ukraine, Prospect Nauki 46, Kiev 03028 (Ukraine); Yakovkin, I.N., E-mail: yakov@iop.kiev.ua [Institute of Physics of National Academy of Sciences of Ukraine, Prospect Nauki 46, Kiev 03028 (Ukraine); Zeze, D.A. [School of Engineering & Computing Sciences, Durham University, Durham DH1 3LE (United Kingdom)

    2015-10-30

    Graphical abstract: The band structures, DOS, and Fermi surfaces for the MoS{sub 2} bilayer with adsorbed (a, c, e) and intercalated (b, d, f) Li (1 × 1) layer. - Highlights: • Adsorbed or intercalated Li monolayer makes the MoS{sub 2} surface metallic. • Increasing density of adsorbed Li leads to the nonmetal-to-metal transition in the layer. • Lithium inserted into MoS{sub 2} bilayers increases the interlayer interaction. - Abstract: Performed density-functional theory (DFT) calculations have shown that the Li adsorption on the MoS{sub 2} (0 0 0 1) surface, as well as Li intercalation into the space between MoS{sub 2} layers, transforms the semiconductor band structure of MoS{sub 2} into metallic. For the (√3 × √3) – R30° Li layer, the band structures of the MoS{sub 2} bilayer with adsorbed and intercalated Li are very similar, while for higher Li concentrations, the character of metallization for the adsorbed layer substantially differs from that of the MoS{sub 2}–Li–MoS{sub 2} layered system. In particular, for the adsorbed (1 × 1) Li monolayer, the increased density of the layer leads to the nonmetal-to-metal transition, which is evident from the appearance of the band crossing E{sub F} with an upward dispersion, pertinent to simple metals. It has been demonstrated that intercalated Li substantially increases the interlayer interaction in MoS{sub 2}. Specifically, the estimated 0.12 eV energy of the interlayer interaction in the MoS{sub 2} bilayer increases to 0.60 eV. This result is also consistent with results of earlier DFT calculations and available experimental results for alkali-intercalated graphene layers, which have demonstrated a substantial increase in the stiffness due to intercalation of alkalis.

  6. Rashba splitting of 100 meV in Au-intercalated graphene on SiC

    Energy Technology Data Exchange (ETDEWEB)

    Marchenko, D.; Varykhalov, A.; Sánchez-Barriga, J.; Rader, O. [Helmholtz-Zentrum Berlin für Materialien und Energie, Elektronenspeicherring BESSY II, Albert-Einstein-Straße 15, 12489 Berlin (Germany); Seyller, Th. [Institut für Physik, Technische Universität Chemnitz, Reichenhainer Strasse 70, 09126 Chemnitz (Germany)

    2016-04-25

    Intercalation of Au can produce giant Rashba-type spin-orbit splittings in graphene, but this has not yet been achieved on a semiconductor substrate. For graphene/SiC(0001), Au intercalation yields two phases with different doping. We observe a 100 meV Rashba-type spin-orbit splitting at 0.9 eV binding energy in the case of p-type graphene after Au intercalation. We show that this giant splitting is due to hybridization and much more limited in energy and momentum space than for Au-intercalated graphene on Ni.

  7. Kaolinite Nanocomposite Platelets Synthesized by Intercalation and Imidization of Poly(styrene-co-maleic anhydride

    Directory of Open Access Journals (Sweden)

    Pieter Samyn

    2015-07-01

    Full Text Available A synthesis route is presented for the subsequent intercalation, exfoliation and surface modification of kaolinite (Kln by an imidization reaction of high-molecular weight poly(styrene-co-maleic anhydride or SMA in the presence of ammonium hydroxide. In a first step, the intercalation of ammonolyzed SMA by guest displacement of intercalated dimethylsulfoxide has been proven. In a second step, the imidization of ammonolyzed SMA at 160 °C results in exfoliation of the kaolinite layers and deposition of poly(styrene-co-maleimide or SMI nanoparticles onto the kaolinite surfaces. Compared with a physical mixture of Kln/SMI, the chemically reacted Kln/SMI provides more efficient exfoliation and hydrogen bonding between the nanoparticles and the kaolinite. The kaolinite nanocomposite particles are synthesized in aqueous dispersion with solid content of 65 wt %. The intercalation and exfoliation are optimized for a concentration ratio of Kln/SMI = 70:30, resulting in maximum intercalation and interlayer distance in combination with highest imide content. After thermal curing at 135 °C, the imidization proceeds towards a maximum conversion of the intermediate amic acid moieties. The changes in O–H stretching and kaolinite lattice vibrations have been illustrated by infrared and FT-Raman spectroscopy, which allow for a good quantification of concentration and imidization effects.

  8. Preparation, quantitative surface analysis, intercalation characteristics and industrial implications of low temperature expandable graphite

    Science.gov (United States)

    Peng, Tiefeng; Liu, Bin; Gao, Xuechao; Luo, Liqun; Sun, Hongjuan

    2018-06-01

    Expandable graphite is widely used as a new functional carbon material, especially as fire-retardant; however, its practical application is limited due to the high expansion temperature. In this work, preparation process of low temperature and highly expandable graphite was studied, using natural flake graphite as raw material and KMnO4/HClO4/NH4NO3 as oxidative intercalations. The structure, morphology, functional groups and thermal properties were characterized during expanding process by Fourier transform infrared spectroscopy (FTIR), Raman spectra, thermo-gravimetry differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD), and scanning electron microscope (SEM). The analysis showed that by oxidation intercalation, some oxygen-containing groups were grafted on the edge and within the graphite layer. The intercalation reagent entered the graphite layer to increase the interlayer spacing. After expansion, the original flaky expandable graphite was completely transformed into worm-like expanded graphite. The order of graphite intercalation compounds (GICs) was proposed and determined to be 3 for the prepared expandable graphite, based on quantitative XRD peak analysis. Meanwhile, the detailed intercalation mechanisms were also proposed. The comprehensive investigation paved a benchmark for the industrial application of such sulfur-free expanded graphite.

  9. Direct intercalation of cisplatin into zirconium phosphate nanoplatelets for potential cancer nanotherapy

    Science.gov (United States)

    Díaz, Agustín; González, Millie L.; Pérez, Riviam J.; David, Amanda; Mukherjee, Atashi; Báez, Adriana; Clearfield, Abraham

    2014-01-01

    We report the use of zirconium phosphate nanoplatelets (ZrP) for the encapsulation of the anticancer drug cisplatin and its delivery to tumor cells. Cisplatin was intercalated into ZrP by direct-ion exchange and was tested in-vitro for cytotoxicity in the human breast cancer (MCF-7) cell line. The structural characterization of the intercalated cisplatin in ZrP suggests that during the intercalation process, the chloride ligands of the cisplatin complex were substituted by phosphate groups within the layers. Consequently, a new phosphate phase with the platinum complex directly bound to ZrP (cisPt@ZrP) is produced with an interlayer distance of 9.3 Å. The in-vitro release profile of the intercalated drug by pH stimulus shows that at low pH under lysosomal conditions the platinum complex is released with simultaneous hydrolysis of the zirconium phosphate material, while at higher pH the complex is not released. Experiments with the MCF-7 cell line show that cisPt@ZrP reduced the cell viability up to 40%. The cisPt@ZrP intercalation product is envisioned as a future nanotherapy agent for cancer. Taking advantage of the shape and sizes of the ZrP particles and controlled release of the drug at low pH, it is intended to exploit the enhanced permeability and retention effect of tumors, as well as their intrinsic acidity, for the destruction of malignant cells. PMID:24072038

  10. Thermal analysis and infrared emission spectroscopic study of halloysite-potassium acetate intercalation compound

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Hongfei [School of Geoscience and Surveying Engineering, China University of Mining and Technology, Beijing 100083 China (China); School of Mining Engineering, Inner Mongolia University of Science and Technology, Baotou 014010 (China); Chemistry Discipline, Faculty of Science and Technology, Queensland University of Technology, 2 George Street, GPO Box 2434, Brisbane, Queensland 4001 (Australia); Liu, Qinfu [School of Geoscience and Surveying Engineering, China University of Mining and Technology, Beijing 100083 China (China); Yang, Jing [Chemistry Discipline, Faculty of Science and Technology, Queensland University of Technology, 2 George Street, GPO Box 2434, Brisbane, Queensland 4001 (Australia); Zhang, Jinshan [School of Mining Engineering, Inner Mongolia University of Science and Technology, Baotou 014010 (China); Frost, Ray L., E-mail: r.frost@qut.edu.au [Chemistry Discipline, Faculty of Science and Technology, Queensland University of Technology, 2 George Street, GPO Box 2434, Brisbane, Queensland 4001 (Australia)

    2010-11-20

    The thermal decomposition of halloysite-potassium acetate intercalation compound was investigated by thermogravimetric analysis and infrared emission spectroscopy. The X-ray diffraction patterns indicated that intercalation of potassium acetate into halloysite caused an increase of the basal spacing from 1.00 to 1.41 nm. The thermogravimetry results show that the mass losses of intercalation the compound occur in main three main steps, which correspond to (a) the loss of adsorbed water, (b) the loss of coordination water and (c) the loss of potassium acetate and dehydroxylation. The temperature of dehydroxylation and dehydration of halloysite is decreased about 100 {sup o}C. The infrared emission spectra clearly show the decomposition and dehydroxylation of the halloysite intercalation compound when the temperature is raised. The dehydration of the intercalation compound is followed by the loss of intensity of the stretching vibration bands at region 3600-3200 cm{sup -1}. Dehydroxylation is followed by the decrease in intensity in the bands between 3695 and 3620 cm{sup -1}. Dehydration was completed by 300 {sup o}C and partial dehydroxylation by 350 {sup o}C. The inner hydroxyl group remained until around 500 {sup o}C.

  11. Adsorption of Phosphate Ion in Water with Lithium-Intercalated Gibbsite

    Directory of Open Access Journals (Sweden)

    Riwandi Sihombing

    2015-12-01

    Full Text Available In order to enhance adsorption capacity of gibbsite (Al(OH3 as an adsorbent for the adsorption of phosphate in water, gibbsite was modified through lithium-intercalation. The purification method of Tributh and Lagaly was applied prior to intercalation. The Li-Intercalation was prepared by the dispersion of gibbsite into LiCl solution for 24 hours. This intercalation formed an cationic clay with the structure of [LiAl2(OH6]+ and exchangeable Cl- anions in the gibbsite interlayer. A phosphate adsorption test using Lithium-intercalated gibbsite (LIG resulted in optimum adsorption occurring at pH 4.5 with an adsorption capacity of 11.198 mg phosphate/g LIG which is equivalent with 1.04 wt% LIG. The adsorption capacity decreased with decreasing amounts of H2PO4-/HPO4- species in the solution. This study showed that LIG has potential as an adsorbent for phosphate in an aqueous solution with pH 4.5–9.5.

  12. Synthesis of reduced graphene oxide intercalated ZnO quantum dots nanoballs for selective biosensing detection

    International Nuclear Information System (INIS)

    Chen, Jing; Zhao, Minggang; Li, Yingchun; Fan, Sisi; Ding, Longjiang; Liang, Jingjing; Chen, Shougang

    2016-01-01

    Highlights: • A MWCNTs/rGO/ZnO quantum dots intercalation nanoballs decorated 3D hierarchical architecture is fabricated on Ni foam. • Large numbers of ZnO quantum dots are intercalated by rGO sheets to construct hierarchical nanoballs. • Improved mechanical, kinetic and electrochemical properties are found. • The strong interfacial effect makes the material can be used for selective detection of dopamine, ascorbic acid and uric acid. - Abstract: ZnO quantum dots (QDs), reduced graphene oxide (rGO) and multi-walled carbon nanotubes (MWCNTs) are always used in sensors due to their excellent electrochemical characteristics. In this work, ZnO QDs were intercalated by rGO sheets with cross-linked MWCNTs to construct intercalation nanoballs. A MWCNTs/rGO/ZnO QDs 3D hierarchical architecture was fabricated on supporting Ni foam, which exhibited excellent mechanical, kinetic and electrochemical properties. The intercalation construction can introduce strong interfacial effects to improve the surface electronic state. The selectively determinate of uric acid, dopamine, and ascorbic acid by an electrode material using distinct applied potentials was realized.

  13. Synthesis of reduced graphene oxide intercalated ZnO quantum dots nanoballs for selective biosensing detection

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jing; Zhao, Minggang, E-mail: zhaomg@ouc.edu.cn; Li, Yingchun; Fan, Sisi; Ding, Longjiang; Liang, Jingjing; Chen, Shougang, E-mail: sgchen@ouc.edu.cn

    2016-07-15

    Highlights: • A MWCNTs/rGO/ZnO quantum dots intercalation nanoballs decorated 3D hierarchical architecture is fabricated on Ni foam. • Large numbers of ZnO quantum dots are intercalated by rGO sheets to construct hierarchical nanoballs. • Improved mechanical, kinetic and electrochemical properties are found. • The strong interfacial effect makes the material can be used for selective detection of dopamine, ascorbic acid and uric acid. - Abstract: ZnO quantum dots (QDs), reduced graphene oxide (rGO) and multi-walled carbon nanotubes (MWCNTs) are always used in sensors due to their excellent electrochemical characteristics. In this work, ZnO QDs were intercalated by rGO sheets with cross-linked MWCNTs to construct intercalation nanoballs. A MWCNTs/rGO/ZnO QDs 3D hierarchical architecture was fabricated on supporting Ni foam, which exhibited excellent mechanical, kinetic and electrochemical properties. The intercalation construction can introduce strong interfacial effects to improve the surface electronic state. The selectively determinate of uric acid, dopamine, and ascorbic acid by an electrode material using distinct applied potentials was realized.

  14. INTERPRETATION OF POTENTIAL INTERMITTENCE TITRATION TECHNIQUE EXPERIMENTS FOR VARIOUS Li-INTERCALATION ELECTRODES

    Directory of Open Access Journals (Sweden)

    M.D.Levi

    2002-01-01

    Full Text Available In this paper we compare two different approaches for the calculation of the enhancement factor Wi, based on its definition as the ratio of the chemical and the component diffusion coefficients for species in mixed-conduction electrodes, originated from the "dilute solution" or "lattice gas" models for the ion system. The former approach is only applicable for small changes of the ion concentration while the latter allows one to consider a broad range of intercalation levels. The component diffusion coefficient of lithium ions has been determined for a series of lithium intercalation anodes and cathodes. A new "enhancement factor" for the ion transport has been defined and its relations to the intercalation capacitance and the intercalation isotherm have been established. A correlation between the dependences of the differential capacitance and the partial ion conductivity on the potential has been observed. It is considered as a prove that the intercalation process is controlled by the availability of sites for Li-ion insertion rather than by the concurrent insertion of the counter-balancing electronic species.

  15. Potential-modulated intercalation of alkali cations into metal hexacyanoferrate coated electrodes. 1998 annual progress report

    International Nuclear Information System (INIS)

    Schwartz, D.T.

    1998-01-01

    'This program is studying potential-driven cation intercalation and deintercalation in metal hexacyanoferrate compounds, with the eventual goal of creating materials with high selectivity for cesium separations and long cycle lifetimes. The separation of radiocesium from other benign cations has important implications for the cost of processing a variety of cesium contaminated DOE wasteforms. This report summarizes results after nine months of work. Much of the initial efforts have been directed towards quantitatively characterizing the selectivity of nickel hexacyanoferrate derivatized electrodes for intercalating cesium preferentially over other alkali metal cations. Using energy dispersive xray spectroscopy (ex-situ, but non-destructive) and ICP analysis (ex-situ and destructive), the authors have demonstrated that the nickel hexacyanoferrate lattice has a strong preference for intercalated cesium over sodium. For example, when ions are reversibly loaded into a nickel hexacyanoferrate thin film from a solution containing 0.9999 M Na + and 0.0001 M Cs + , the film intercalates 40% as much Cs + as when loaded from pure 1 M Cs + containing electrolyte (all electrolytes use nitrates as the common anion). The authors have also shown that, contrary to the common assumptions found in the literature, a significant fraction of the thin film is not active initially. A new near infrared laser has been purchased and is being added to the Raman spectroscopy facilities to allow in-situ studies of the intercalation processes.'

  16. Synthesis and Ligand Non-Innocence of Thiolate-Ligated (N4S) Iron(II) and Nickel(II) Bis(imino)pyridine Complexes

    Science.gov (United States)

    Widger, Leland R.; Jiang, Yunbo; Siegler, Maxime; Kumar, Devesh; Latifi, Reza; de Visser, Sam P.; Jameson, Guy N.L.; Goldberg, David P.

    2013-01-01

    The known iron(II) complex [FeII(LN3S)(OTf)] (1) was used as starting material to prepare the new biomimetic (N4S(thiolate)) iron(II) complexes [FeII(LN3S)(py)](OTf) (2) and [FeII(LN3S)(DMAP)](OTf) (3), where LN3S is a tetradentate bis(imino)pyridine (BIP) derivative with a covalently tethered phenylthiolate donor. These complexes were characterized by X-ray crystallography, UV-vis, 1H NMR, and Mössbauer spectroscopy, as well as electrochemistry. A nickel(II) analogue, [NiII(LN3S)](BF4) (5), was also synthesized and characterized by structural and spectroscopic methods. Cyclic voltammetric studies showed 1 – 3 and 5 undergo a single reduction process with E1/2 between −0.9 to −1.2 V versus Fc+/Fc. Treatment of 3 with 0.5% Na/Hg amalgam gave the mono-reduced complex [Fe(LN3S)(DMAP)]0 (4), which was characterized by X-ray crystallography, UV-vis, EPR (g = [2.155, 2.057, 2.038]) and Mössbauer (δ = 0.33 mm s−1; ΔEQ = 2.04 mm s−1) spectroscopies. Computational methods (DFT) were employed to model complexes 3 – 5. The combined experimental and computational studies show that 1 – 3 are 5-coordinate, high-spin (S = 2) FeII complexes, whereas 4 is best described as a 5-coordinate, intermediate-spin (S = 1) FeII complex antiferromagnetically coupled to a ligand radical. This unique electronic configuration leads to an overall doublet spin (Stotal = ½) ground state. Complexes 2 and 3 are shown to react with O2 to give S-oxygenated products, as previously reported for 1. In contrast, the mono-reduced 4 appears to react with O2 to give a mixture of S- and Fe-oxygenates. The nickel(II) complex 5 does not react with O2, and even when the mono-reduced nickel complex is produced, it appears to undergo only outer-sphere oxidation with O2. PMID:23992096

  17. The forces that shape embryos: physical aspects of convergent extension by cell intercalation

    International Nuclear Information System (INIS)

    Keller, Ray; Shook, David; Skoglund, Paul

    2008-01-01

    We discuss the physical aspects of the morphogenic process of convergence (narrowing) and extension (lengthening) of tissues by cell intercalation. These movements, often referred to as 'convergent extension', occur in both epithelial and mesenchymal tissues during embryogenesis and organogenesis of invertebrates and vertebrates, and they play large roles in shaping the body plan during development. Our focus is on the presumptive mesodermal and neural tissues of the Xenopus (frog) embryo, tissues for which some physical measurements have been made. We discuss the physical aspects of how polarized cell motility, oriented along future tissue axes, generate the forces that drive oriented cell intercalation and how this intercalation results in convergence and extension or convergence and thickening of the tissue. Our goal is to identify aspects of these morphogenic movements for further biophysical, molecular and cell biological, and modeling studies

  18. Formation Dynamics of Potassium-Based Graphite Intercalation Compounds: An Ab Initio Study

    Science.gov (United States)

    Jiang, Xiankai; Song, Bo; Tománek, David

    2018-04-01

    This paper is a contribution to the Physical Review Applied collection in memory of Mildred S. Dresselhaus. We use ab initio molecular dynamics simulations to study the microscopic dynamics of potassium intercalation in graphite. Upon adsorbing on graphite from the vapor phase, K atoms transfer their valence charge to the substrate. K atoms adsorbed on the surface diffuse rapidly along the graphene basal plane and eventually enter the interlayer region following a "U -turn" across the edge, gaining additional energy. This process is promoted at higher coverages associated with higher K pressure, leading to the formation of a stable intercalation compound. We find that the functionalization of graphene edges is an essential prerequisite for intercalation since bare edges reconstruct and reconnect, closing off the entry channels for the atoms.

  19. Thermodynamics and kinetics of phase transformation in intercalation battery electrodes - phenomenological modeling

    Energy Technology Data Exchange (ETDEWEB)

    Lai Wei, E-mail: laiwei@msu.ed [Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI 48824 (United States); Ciucci, Francesco [Heidelberg Graduate School of Mathematical and Computational Methods for the Sciences, University of Heidelberg, INF 368 D - 69120 Heidelberg (Germany)

    2010-12-15

    Thermodynamics and kinetics of phase transformation in intercalation battery electrodes are investigated by phenomenological models which include a mean-field lattice-gas thermodynamic model and a generalized Poisson-Nernst-Planck equation set based on linear irreversible thermodynamics. The application of modeling to a porous intercalation electrode leads to a hierarchical equivalent circuit with elements of explicit physical meanings. The equivalent circuit corresponding to the intercalation particle of planar, cylindrical and spherical symmetry is reduced to a diffusion equation with concentration dependent diffusivity. The numerical analysis of the diffusion equation suggests the front propagation behavior during phase transformation. The present treatment is also compared with the conventional moving boundary and phase field approaches.

  20. Intercalating cobalt between graphene and iridium (111): Spatially dependent kinetics from the edges

    Science.gov (United States)

    Vlaic, Sergio; Rougemaille, Nicolas; Kimouche, Amina; Burgos, Benito Santos; Locatelli, Andrea; Coraux, Johann

    2017-10-01

    Using low-energy electron microscopy, we image in real time the intercalation of a cobalt monolayer between graphene and the (111) surface of iridium. Our measurements reveal that the edges of a graphene flake represent an energy barrier to intercalation. Based on a simple description of the growth kinetics, we estimate this energy barrier and find small, but substantial, local variations. These local variations suggest a possible influence of the graphene orientation with respect to its substrate and of the graphene edge termination on the energy value of the barrier height. Besides, our measurements show that intercalated cobalt is energetically more favorable than cobalt on bare iridium, indicating a surfactant role of graphene.

  1. Hybrid Doping of Few-Layer Graphene via a Combination of Intercalation and Surface Doping

    KAUST Repository

    Mansour, Ahmed

    2017-05-23

    Surface molecular doping of graphene has been shown to modify its work function and increase its conductivity. However, the associated shifts in work function and increases in carrier concentration are highly coupled and limited by the surface coverage of dopant molecules on graphene. Here we show that few-layer graphene (FLG) can be doped using a hybrid approach, effectively combining surface doping by larger (metal-)organic molecules, while smaller molecules, such as Br2 and FeCl3, intercalate into the bulk. Intercalation tunes the carrier concentration more effectively, whereas surface doping of intercalated FLG can be used to tune its work function without reducing the carrier mobility. This multi-modal doping approach yields a very high carrier density and tunable work function for FLG, demonstrating a new versatile platform for fabricating graphene-based contacts for electronic, optoelectronic and photovoltaic applications.

  2. Electron doping through lithium intercalation to interstitial channels in tetrahedrally bonded SiC

    Energy Technology Data Exchange (ETDEWEB)

    Sakai, Yuki [Department of Applied Physics, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Center for Computational Materials, Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, Texas 78712 (United States); Oshiyama, Atsushi [Department of Applied Physics, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

    2015-11-07

    We report on first-principles calculations that clarify the effect of lithium atom intercalation into zinc blende 3C-silicon carbide (3C-SiC) on electronic and structural properties. Lithium atoms inside 3C-SiC are found to donate electrons to 3C-SiC that is an indication of a new way of electron doping through the intercalation. The electrons doped into the conduction band interact with lithium cations and reduce the band spacing between the original valence and conduction bands. We have also found that a silicon monovacancy in 3C-SiC promotes the lithium intercalation, showing that the vacancy generation makes SiC as a possible anode material for lithium-ion battery.

  3. Intercalation of diclofenac in modified Zn/Al hydrotalcite-like preparation

    Science.gov (United States)

    Heraldy, E.; Suprihatin, R. W.; Pranoto

    2016-02-01

    The intercalation of a pharmaceutically active material diclofenac into modified Zn/Al Hydrotalcite-like (Zn/Al HTlc) preparation has been investigated by the coprecipitation and ion exchange method, respectively. The synthetic materials were characterized using X- Ray Diffraction (XRD); Fourier transforms infrared spectroscopy (FTIR); Scanning Electron Microscope (SEM); X-Ray Fluorescence (XRF) and surface area analyzer. The results show that the basal spacing of the product was expanded to 11.03 A for direct synthesis and 10.68 A for indirect synthesis, suggesting that diclofenac anion was intercalated into Zn/Al HTlc and arranged in a tilted bilayer fashion and the specific surface area of material increased after the intercalation of diclofenac.

  4. Hybrid Doping of Few-Layer Graphene via a Combination of Intercalation and Surface Doping

    KAUST Repository

    Mansour, Ahmed; Kirmani, Ahmad R.; Barlow, Stephen; Marder, Seth R.; Amassian, Aram

    2017-01-01

    Surface molecular doping of graphene has been shown to modify its work function and increase its conductivity. However, the associated shifts in work function and increases in carrier concentration are highly coupled and limited by the surface coverage of dopant molecules on graphene. Here we show that few-layer graphene (FLG) can be doped using a hybrid approach, effectively combining surface doping by larger (metal-)organic molecules, while smaller molecules, such as Br2 and FeCl3, intercalate into the bulk. Intercalation tunes the carrier concentration more effectively, whereas surface doping of intercalated FLG can be used to tune its work function without reducing the carrier mobility. This multi-modal doping approach yields a very high carrier density and tunable work function for FLG, demonstrating a new versatile platform for fabricating graphene-based contacts for electronic, optoelectronic and photovoltaic applications.

  5. Preparation and characterization of trans-RhCl(CO)(TPPTS)2-intercalated layered double hydroxides

    International Nuclear Information System (INIS)

    Zhang Xian; Wei Min; Pu Min; Li Xianjun; Chen Hua; Evans, David G.; Duan Xue

    2005-01-01

    trans-RhCl(CO)(TPPTS) 2 (TPPTS=tris(m-sulfonatophenyl)phosphine) has been intercalated into Zn-Al layered double hydroxides (LDHs) by the method of ion exchange. The structure, composition and thermal stability of the composite material have been characterized by powder X-ray diffraction, Fourier transform infrared and 31 P solid-state magic-angle spinning nuclear magnetic resonance spectroscopy, elemental analysis, thermogravimetry, and differential thermal analysis. The geometry of trans-RhCl(CO)(TPPTS) 2 was fully optimized using the PM3 semiempirical molecular orbital method, and a schematic model for the intercalated species has been proposed. The thermal stability of trans-RhCl(CO)(TPPTS) 2 is significantly enhanced by intercalation, which suggests that such materials may have prospective application as the basis of a supported catalyst system for the hydroformylation of higher olefins

  6. Intercalation compounds of vanadium pentoxide hydrated with metalporphyrins and lanthanide ions

    International Nuclear Information System (INIS)

    Oliveira, Herenilton Paulino

    1994-01-01

    The lamellar structure of the vanadium pentoxide matrix allows the intercalation of organic molecules, ions and conductor polymers. It is important to emphasize that the vanadium oxide matrix is an intrinsic semiconductor and presents electrochromic properties. In the beginning of this work the method of synthesis and the electrochemical and electrochromic properties were extensively explored. The effect of alkaline metal and lanthanide ions on the structure of vanadium oxide matrix was studied by X-ray and infrared spectroscopy. Moreover, the influence of those ions in the electrochemical, spectro electrochemical and magnetic properties were studied. Finally, some intercalation compounds containing porphyrins were prepared and characterized by elemental analysis, X-ray diffraction, and electronic, vibrational, Moessbauer and X-ray fluorescence spectroscopy. The electrochemical and spectro electrochemical properties were investigated. And the performance of an iron porphyrin based intercalation compound as catalyst for molecular oxygen reduction was evaluated using the rotating ring-disc electrode technique. (author)

  7. X-ray Spectroscopy and Imaging as Multiscale Probes of Intercalation Phenomena in Cathode Materials

    Science.gov (United States)

    Horrocks, Gregory A.; De Jesus, Luis R.; Andrews, Justin L.; Banerjee, Sarbajit

    2017-09-01

    Intercalation phenomena are at the heart of modern electrochemical energy storage. Nevertheless, as out-of-equilibrium processes involving concomitant mass and charge transport, such phenomena can be difficult to engineer in a predictive manner. The rational design of electrode architectures requires mechanistic understanding of physical phenomena spanning multiple length scales, from atomistic distortions and electron localization at individual transition metal centers to phase inhomogeneities and intercalation gradients in individual particles and concentration variances across ensembles of particles. In this review article, we discuss the importance of the electronic structure in mediating electrochemical storage and mesoscale heterogeneity. In particular, we discuss x-ray spectroscopy and imaging probes of electronic and atomistic structure as well as statistical regression methods that allow for monitoring of the evolution of the electronic structure as a function of intercalation. The layered α-phase of V2O5 is used as a model system to develop fundamental ideas on the origins of mesoscale heterogeneity.

  8. Mössbauer study of pH dependence of iron-intercalation in montmorillonite

    Energy Technology Data Exchange (ETDEWEB)

    Kuzmann, E., E-mail: kuzmann@caesar.elte.hu [Eötvös Loránd University, Institute of Chemistry (Hungary); Garg, V. K.; Singh, H.; Oliveira, A. C. de; Pati, S. S. [University of Brasília, Institute of Physics (Brazil); Homonnay, Z.; Rudolf, M. [Eötvös Loránd University, Institute of Chemistry (Hungary); Molnár, Á. M.; Kovács, E. M. [University of Debrecen, Imre Lajos Isotope Laboratory, Department of Colloid and Environmental Chemistry (Hungary); Baranyai, E. [University of Debrecen, Department of Inorganic and Analytical Chemistry (Hungary); Kubuki, S. [Tokyo Metropolitan University, Department of Chemistry (Japan); Nagy, N. M.; Kónya, J. [University of Debrecen, Imre Lajos Isotope Laboratory, Department of Colloid and Environmental Chemistry (Hungary)

    2016-12-15

    {sup 57}Fe Mössbauer spectroscopy and XRD have successfully been applied to show the incorporation of Fe ion into the interlayer space of montmorillonite via treatment with FeCl {sub 3} in acetone. The 78K {sup 57}Fe Mössbauer spectra of montmorillonite samples reflected magnetically split spectrum part indicating the intercalation of iron into the interlayer of montmorillonite via the treatment with FeCl {sub 3}+acetone and washed with water until the initial pH=2.3 increased to pH=4.14. It was found that the occurrence of intercalated iron in the form of oxide-oxihydroxide in montmorillonite increases with the pH. Intercalation was confirmed by the gradual increase in the basal spacing d{sub 001} with pH.

  9. Intercalation of hydrotalcites with hexacyanoferrate(II) and (III)-a thermoRaman spectroscopic study

    International Nuclear Information System (INIS)

    Frost, Ray L.; Musumeci, Anthony W.; Bouzaid, Jocelyn; Adebajo, Moses O.; Martens, Wayde N.; Theo Kloprogge, J.

    2005-01-01

    Raman spectroscopy using a hot stage indicates that the intercalation of hexacyanoferrate(II) and (III) in the interlayer space of a Mg, Al hydrotalcites leads to layered solids where the intercalated species is both hexacyanoferrate(II) and (III). Raman spectroscopy shows that depending on the oxidation state of the initial hexacyanoferrate partial oxidation and reduction takes place upon intercalation. For the hexacyanoferrate(III) some partial reduction occurs during synthesis. The symmetry of the hexacyanoferrate decreases from O h existing for the free anions to D 3d in the hexacyanoferrate interlayered hydrotalcite complexes. Hot stage Raman spectroscopy reveals the oxidation of the hexacyanoferrate(II) to hexacyanoferrate(III) in the hydrotalcite interlayer with the removal of the cyanide anions above 250 deg. C. Thermal treatment causes the loss of CN ions through the observation of a band at 2080cm -1 . The hexacyanoferrate (III) interlayered Mg, Al hydrotalcites decomposes above 150 deg. C

  10. The ground states of iron(III) porphines: role of entropy-enthalpy compensation, Fermi correlation, dispersion, and zero-point energies.

    Science.gov (United States)

    Kepp, Kasper P

    2011-10-01

    Porphyrins are much studied due to their biochemical relevance and many applications. The density functional TPSSh has previously accurately described the energy of close-lying electronic states of transition metal systems such as porphyrins. However, a recent study questioned this conclusion based on calculations of five iron(III) porphines. Here, we compute the geometries of 80 different electronic configurations and the free energies of the most stable configurations with the functionals TPSSh, TPSS, and B3LYP. Zero-point energies and entropy favor high-spin by ~4kJ/mol and 0-10kJ/mol, respectively. When these effects are included, and all electronic configurations are evaluated, TPSSh correctly predicts the spin of all the four difficult phenylporphine cases and is within the lower bound of uncertainty of any known theoretical method for the fifth, iron(III) chloroporphine. Dispersion computed with DFT-D3 favors low-spin by 3-53kJ/mol (TPSSh) or 4-15kJ/mol (B3LYP) due to the attractive r(-6) term and the shorter distances in low-spin. The very large and diverse corrections from TPSS and TPSSh seem less consistent with the similarity of the systems than when calculated from B3LYP. If the functional-specific corrections are used, B3LYP and TPSSh are of equal accuracy, and TPSS is much worse, whereas if the physically reasonable B3LYP-computed dispersion effect is used for all functionals, TPSSh is accurate for all systems. B3LYP is significantly more accurate when dispersion is added, confirming previous results. Copyright © 2011 Elsevier Inc. All rights reserved.

  11. Investigation of the interaction of iron(III) complexes with dAMP by ESI-MS, MALDI-MS and potentiometric titration: insights into synthetic nuclease behavior.

    Science.gov (United States)

    Fernandes, Christiane; Oliveira Moreira, Rafaela; Lube, Leonardo M; Horn, Adolfo; Szpoganicz, Bruno; Sherrod, Stacy; Russell, David H

    2010-06-07

    We report herein the characterization by electrospray ionization (ESI) mass spectrometry (MS), matrix assisted laser desorption ionization (MALDI-MS) and potentiometric titration of three iron(III) compounds: [Fe(III)(HPClNOL)Cl2]·NO3 (1), [Cl(HPClNOL)Fe(III)-(μ-O)-Fe(III)(HPClNOL)Cl]·Cl2·H2O (2) and [(SO4)(HPClNOL)Fe(III)-(μ-O)-Fe(III)(HPClNOL)(SO4)]·6H2O (3), where HPClNOL= 1-(bis-pyridin-2-ylmethyl-amino)-3-chloropropan-2-ol). Despite the fact that the compounds have distinct structures in solid state and non-buffered solution, all compounds present similar ESI and MALDI mass spectra in a buffered medium (pH 7.0). At this pH, the species [(PClNOL)Fe(III)-(μ-O)-Fe(III)(PClNOL)](2+) (m/z 354) was observed for all the compounds under investigation. Potentiometric titration confirms a similar behavior for all compounds, indicating that the dihydroxo form [(OH)(HPClNOL)Fe(III)-(μ-O)-Fe(III)(HPClNOL)(OH)](2+) is the major species at pH 7.0, for all the compounds. The products of the interaction between compounds (1), (2) and (3) and dAMP (2'-deoxyadenosine-5'-monophosphate) in a buffered medium (pH 7.0) were identified by MALDI-MS/MS. The fragmentation data obtained by MS/MS allow one to identify the nature of the interaction between the iron(III) compounds and dAMP, revealing the direct interaction between the iron center and phosphate groups.

  12. Enhancing the efficiency of lithium intercalation in carbon nanotube bundles using surface functional groups.

    Science.gov (United States)

    Xiao, Shiyan; Zhu, Hong; Wang, Lei; Chen, Liping; Liang, Haojun

    2014-08-14

    The effect of surface functionalization on the ability and kinetics of lithium intercalation in carbon nanotube (CNT) bundles has been studied by comparing the dynamical behaviors of lithium (Li) ions in pristine and -NH2 functionalized CNTs via ab initio molecular dynamics simulations. It was observed that lithium intercalation has been achieved quickly for both the pristine and surface functionalized CNT bundle. Our calculations demonstrated for the first time that CNT functionalization improved the efficiency of lithium intercalation significantly at both low and high Li ion density. Moreover, we found that keeping the nanotubes apart with an appropriate distance and charging the battery at a rational rate were beneficial to achieve a high rate of lithium intercalation. Besides, the calculated adsorption energy curves indicated that the potential wells in the system of -NH2 functionalized CNT were deeper than that of the pristine CNT bundle by 0.74 eV, and a third energy minimum with a value of 2.64 eV existed at the midpoint of the central axis of the nanotube. Thus, it would be more difficult to remove Li ions from the nanotube interior after surface functionalization. The barrier for lithium diffusion in the interior of the nanotube is greatly decreased because of the surface functional groups. Based on these results, we would suggest to "damage" the nanotube by introducing defects at its sidewall in order to improve not only the capacity of surface functionalized CNTs but also the efficiency of lithium intercalation and deintercalation processes. Our results presented here are helpful in understanding the mechanism of lithium intercalation into nanotube bundles, which may potentially be applied in the development of CNT based electrodes.

  13. Probing the role of intercalating protein sidechains for kink formation in DNA.

    Directory of Open Access Journals (Sweden)

    Achim Sandmann

    Full Text Available Protein binding can induce DNA kinks, which are for example important to enhance the specificity of the interaction and to facilitate the assembly of multi protein complexes. The respective proteins frequently exhibit amino acid sidechains that intercalate between the DNA base steps at the site of the kink. However, on a molecular level there is only little information available about the role of individual sidechains for kink formation. To unravel structural principles of protein-induced DNA kinking we have performed molecular dynamics (MD simulations of five complexes that varied in their architecture, function, and identity of intercalated residues. Simulations were performed for the DNA complexes of wildtype proteins (Sac7d, Sox-4, CcpA, TFAM, TBP and for mutants, in which the intercalating residues were individually or combined replaced by alanine. The work revealed that for systems with multiple intercalated residues, not all of them are necessarily required for kink formation. In some complexes (Sox-4, TBP, one of the residues proved to be essential for kink formation, whereas the second residue has only a very small effect on the magnitude of the kink. In other systems (e.g. Sac7d each of the intercalated residues proved to be individually capable of conferring a strong kink suggesting a partially redundant role of the intercalating residues. Mutation of the key residues responsible for kinking either resulted in stable complexes with reduced kink angles or caused conformational instability as evidenced by a shift of the kink to an adjacent base step. Thus, MD simulations can help to identify the role of individual inserted residues for kinking, which is not readily apparent from an inspection of the static structures. This information might be helpful for understanding protein-DNA interactions in more detail and for designing proteins with altered DNA binding properties in the future.

  14. Hydroxy double salts loaded with bioactive ions: Synthesis, intercalation mechanisms, and functional performance

    Science.gov (United States)

    Y. A. Kaassis, Abdessamad; Xu, Si-Min; Guan, Shanyue; Evans, David G.; Wei, Min; Williams, Gareth R.

    2016-06-01

    The intercalation of the anions of diclofenac (Dic), naproxen (Nap), and valproic acid (Val) into three hydroxy double salts (HDSs) has been explored in this work. Experiments were performed with [Co1.2Zn3.8(OH)8](NO3)2·2H2O (CoZn-NO3), [Ni2Zn3(OH)8](NO3)2·2H2O (NiZn-NO3) and [Zn5(OH)8](NO3)2·2H2O (Zn-NO3). It proved possible to intercalate diclofenac and naproxen into all three HDSs. In contrast, Val could be intercalated into CoZn-NO3 but when it was reacted with Zn-NO3 the HDS structure was destroyed, and the product comprised ZnO. Successful intercalation was verified by X-ray diffraction, IR spectroscopy, and elemental microanalysis. Molecular dynamics simulations showed the Dic and Nap ions to arrange themselves in an "X" shape in the interlayer space, forming a bilayer. Val was found to adopt a position with its aliphatic groups parallel to the HDS layer, again in a bilayer. In situ time resolved X-ray diffraction experiments revealed that intercalation of Dic and Nap into CoZn-NO3 and Zn-NO3 is mechanistically complex, with a number of intermediate phases observed. In contrast, the intercalation of all three guests into NiZn-NO3 and of Val into CoZn-NO3 are simple one step reactions proceeding directly from the starting material to the product. The HDS-drug composites were found to have sustained release profiles.

  15. Layered double hydroxides as supports for intercalation and sustained release of antihypertensive drugs

    International Nuclear Information System (INIS)

    Xia Shengjie; Ni Zheming; Xu Qian; Hu Baoxiang; Hu Jun

    2008-01-01

    Zn/Al layered double hydroxides (LDHs) were intercalated with the anionic antihypertensive drugs Enalpril, Lisinopril, Captopril and Ramipril by using coprecipitation or ion-exchange technique. TG-MS analyses suggested that the thermal stability of Ena - , Lis - (arranged with monolayer, resulted from X-ray diffraction (XRD) and Fourier transform infrared spectra (FT-IR) analysis was enhanced much more than Cap - and Ram - (arranged with bilayer). The release studies show that the release rate of all samples markedly decreased in both pH 4.25 and 7.45. However, the release time of Ena - , Lis - were much longer compared with Cap - , Ram - in both pH 4.25 and 7.45, it is possible that the intercalated guests, arranged with monolayer in the interlayer, show lesser repulsive force and strong affinity with the LDH layers. And the release data followed both the Higuchi-square-root law and the first-order equation well. Based on the analysis of batch release, intercalated structural models as well as the TG-DTA results, we conclude that for drug-LDH, stronger the affinity between intercalated anions and the layers is, better the thermal property and the stability to the acid attack of drug-LDH, and the intercalated anions are easier apt to monolayer arrangement within the interlayer, were presented. - Graphical abstract: A series of antihypertensive drugs including Enalpril, Lisinopril, Captopril and Ramipril were intercalated into Zn/Al-NO 3 -LDHs successfully by coprecipitation or ion-exchange technique. We focus on the structure, thermal property and low/controlled release property of as-synthesized drug-LDH composite intended for the possibility of applying these LDH-antihypertensive nanohybrids in drug delivery and controlled release systems

  16. Neutron scattering in chemistry (scattering from layer lattices and their intercalation compounds - an illustration)

    International Nuclear Information System (INIS)

    White, J.W.

    1983-01-01

    Three cases of molecules on a free surface or inside layer lattice intercalation compounds are discussed to illustrate the use of neutron scattering techniques. The first is the second stage alkali metal-graphite intercalation compounds such as C 24 Cs which adsorb hydrogen, methane and other gases. The second case is methane physisorbed on the basal plane of graphite where the methane-methane interactions are relatively strong. Rotational tunnelling spectroscopy is sensitive to the parameters of the potential. The third case is that of water physisorbed on clay materials such as vermiculite or montmorillonite where the layer thickness can be changed from one to fifty layers. (UK)

  17. Ferric chloride-graphite intercalation compounds as anode materials for Li-ion batteries.

    Science.gov (United States)

    Wang, Lili; Zhu, Yongchun; Guo, Cong; Zhu, Xiaobo; Liang, Jianwen; Qian, Yitai

    2014-01-01

    Ferric chloride-graphite intercalation compounds (FeCl3 -GICs) with stage 1 and stage 2 structures were synthesized by reacting FeCl3 and expanded graphite (EG) in air in a stainless-steel autoclave. As rechargeable Li-ion batteries, these FeCl3 -GICs exhibit high capacity, excellent cycling stability, and superior rate capability, which could be attributed to their unique intercalation features. This work may enable new possibilities for the fabrication of Li-ion batteries. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Isolation of high quality graphene from Ru by solution phase intercalation

    Science.gov (United States)

    Koren, E.; Sutter, E.; Bliznakov, S.; Ivars-Barcelo, F.; Sutter, P.

    2013-09-01

    We introduce a method for isolating graphene grown on epitaxial Ru(0001)/α-Al2O3. The strong graphene/Ru(0001) coupling is weakened by electrochemically driven intercalation of hydrogen underpotentially deposited in aqueous KOH solution, which allows the penetration of water molecules at the graphene/Ru(0001) interface. Following these electrochemically driven processes, the graphene can be isolated by electrochemical hydrogen evolution and transferred to arbitrary supports. Raman and transport measurements demonstrate the high quality of the transferred graphene. Our results show that intercalation, typically carried out in vacuum, can be extended to solution environments for graphene processing under ambient conditions.

  19. The effect of transition metals on the structure of h-BN intercalation compounds

    International Nuclear Information System (INIS)

    Budak, Erhan; Bozkurt, Cetin

    2004-01-01

    In this study, hexagonal boron nitride (h-BN) were synthesized by the modified O'Connor method in the presence of various metal nitrates [M(NO 3 ) x , M=Cr, Mn, Fe, Co, Ni, Cu, Zn, and Ag]. The composites were analyzed by FTIR, XRF, XRD, and SEM techniques. XRD results indicated a change in the interlayer spacing due to the intercalation of Cr, Mn, Fe and Ag. SEM analyses illustrated the grain growth upon metal intercalation even at a temperature of 1320 K

  20. Hydroxy double salts loaded with bioactive ions: Synthesis, intercalation mechanisms, and functional performance

    Energy Technology Data Exchange (ETDEWEB)

    Kaassis, Abdessamad Y.A. [UCL School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX (United Kingdom); Xu, Si-Min; Guan, Shanyue; Evans, David G. [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Wei, Min, E-mail: weimin@mail.buct.edu.cn [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Williams, Gareth R., E-mail: g.williams@ucl.ac.uk [UCL School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX (United Kingdom)

    2016-06-15

    The intercalation of the anions of diclofenac (Dic), naproxen (Nap), and valproic acid (Val) into three hydroxy double salts (HDSs) has been explored in this work. Experiments were performed with [Co{sub 1.2}Zn{sub 3.8}(OH){sub 8}](NO{sub 3}){sub 2}·2H{sub 2}O (CoZn-NO{sub 3}), [Ni{sub 2}Zn{sub 3}(OH){sub 8}](NO{sub 3}){sub 2}·2H{sub 2}O (NiZn-NO{sub 3}) and [Zn{sub 5}(OH){sub 8}](NO{sub 3}){sub 2}·2H{sub 2}O (Zn-NO{sub 3}). It proved possible to intercalate diclofenac and naproxen into all three HDSs. In contrast, Val could be intercalated into CoZn-NO{sub 3} but when it was reacted with Zn-NO{sub 3} the HDS structure was destroyed, and the product comprised ZnO. Successful intercalation was verified by X-ray diffraction, IR spectroscopy, and elemental microanalysis. Molecular dynamics simulations showed the Dic and Nap ions to arrange themselves in an “X” shape in the interlayer space, forming a bilayer. Val was found to adopt a position with its aliphatic groups parallel to the HDS layer, again in a bilayer. In situ time resolved X-ray diffraction experiments revealed that intercalation of Dic and Nap into CoZn-NO{sub 3} and Zn-NO{sub 3} is mechanistically complex, with a number of intermediate phases observed. In contrast, the intercalation of all three guests into NiZn-NO{sub 3} and of Val into CoZn-NO{sub 3} are simple one step reactions proceeding directly from the starting material to the product. The HDS-drug composites were found to have sustained release profiles. - Graphical abstract: Seven new drug intercalates of hydroxy double salts (HDSs) have been prepared and characterised. The intercalation mechanisms have been explored, and the drug release properties of the HDS/drug composites quantified. Display Omitted.

  1. Structural properties and magnetic susceptibility of iron-intercalated titanium ditelluride

    International Nuclear Information System (INIS)

    Pleshchev, V.G.; Titov, A.N.; Titova, S.G.; Kuranov, A.V.

    1997-01-01

    Structural peculiarities and magnetic susceptibility of titanium ditelluride, intercalated by iron, are studied. It is established that the basic motive of crystal structure by intercalation is preserved and the iron atoms are locates in the van der Waals gaps in positions with octahedral coordination. It is shown that the magnetic susceptibility of the Fe 0.25 TiT 2 sample increases approximately by 20 times. The magnetic susceptibility for the Fe 0.33 TiTe 2 samples becomes even much higher

  2. High-resolution 13C nuclear magnetic resonance evidence of phase transition of Rb,Cs-intercalated single-walled nanotubes

    KAUST Repository

    Bouhrara, M.; Saih, Y.; Wågberg, T.; Goze-Bac, C.; Abou-Hamad, E.

    2011-01-01

    charge transfer is applicable at low intercalation level. The new phase at high intercalation level is accompanied by a hybridization of alkali (s) orbitals with the carbon (sp2) orbitals of the single walled nanotubes, which indicate bundle surface sites

  3. The role of iron(II) dilution in the magnetic and photomagnetic properties of the series [Fe(x)Zn(1-x)(bpp)₂](NCSe)₂.

    Science.gov (United States)

    Baldé, Chérif; Desplanches, Cédric; Le Gac, Fréderic; Guionneau, Philippe; Létard, Jean-François

    2014-06-07

    The effects of metal dilution on the spin-crossover behavior of iron(II) in the mixed crystal series [Fe(x)Zn(1-x)(bpp)2](NCSe)2 (bpp = 2,6-bis(pyrazol-3-yl)pyridine) have been studied using magnetic susceptibility, photomagnetism and diffuse reflectivity measurements. For each mixed-crystal system, the thermal spin transition temperature, T(1/2), and the relaxation temperature of the photo-induced high-spin state, T(LIESST), have been systematically determined. It appears that T(1/2) decreases with the metal dilution while T(LIESST) remains unchanged. Dilution also tends to decrease the hysteresis width and smooth the transition curves. These effects were discussed first qualitatively and then quantitatively on the basis of a kinetic study governing the photo-induced back conversion taking into account the relative sizes of Zn(II) and Fe(II) ions. Interestingly, single crystals were obtained for [Fe(0.6)Zn(0.4)(bpp)2](NCSe)2 allowing the X-ray diffraction crystal-structure determination.

  4. Intercalated organic-inorganic perovskites stabilized by fluoroaryl-aryl interactions.

    Science.gov (United States)

    Mitzi, David B; Medeiros, David R; Malenfant, Patrick R L

    2002-04-22

    Crystals of several new hybrid tin(II) iodide-based perovskites, involving 2,3,4,5,6- pentafluorophenethylammonium or phenethylammonium cation bilayers and intercalated aryl or perfluoroaryl molecules, were grown by slow evaporation of a methanol solution containing the hybrid perovskite and the intercalating species. The (C(6)F(5)C(2)H(4)NH(3))(2)SnI(4).(C(6)H(6)) structure was solved at -75 degrees C in a monoclinic C2/c subcell [a = 41.089(12) A, b = 6.134(2) A, c = 12.245(3) A, beta = 94.021(5) degrees, Z = 4] and consists of sheets of corner-sharing distorted SnI(6) octahedra separated by bilayers of pentafluorophenethylammonium cations. The intercalated benzene molecules form a single well-ordered layer interposed between adjacent fluoroaryl cation layers. The corresponding hybrid with an unfluorinated organic cation and fluorinated intercalating molecule, (C(6)H(5)C(2)H(4)NH(3))(2)SnI(4).(C(6)F(6)), is isostructural [a = 40.685(4) A, b = 6.0804(6) A, c = 12.163(1) A, beta = 93.136(2) degrees, Z = 4]. For each intercalated system, close C...C contacts (3.44-3.50 A) between the aromatic cation and the intercalated molecule are indicative of a significant face-to-face interaction, similar to that found in the complex C(6)H(6).C(6)F(6). Crystal growth runs with the organic cation and prospective intercalating molecule either both fluorinated or both unfluorinated did not yield stable intercalated compounds, demonstrating the significance of fluoroaryl-aryl interactions in the current intercalated structures. Thermal analysis of (C(6)F(5)C(2)H(4)NH(3))(2)SnI(4).(C(6)H(6)) and (C(6)H(5)C(2)H(4)NH(3))(2)SnI(4).(C(6)F(6)) crystals yields, in addition to the characteristic transitions of the parent perovskite, endothermic transitions [12.6(5) and 32.1(8) kJ/mol, respectively] with an onset at 145 degrees C and a weight loss corresponding to the complete loss of the intercalated molecule. The relatively high deintercalation temperature (well above the boiling point of

  5. Ethylene glycol intercalation in smectites. molecular dynamics simulation studies

    International Nuclear Information System (INIS)

    Szczerba, Marek; Klapyta, Zenon; Kalinichev, Andrey

    2012-01-01

    Document available in extended abstract form only. Intercalation of ethylene glycol in smectites (glycolation) is widely used to discriminate smectites and vermiculites from other clays and among themselves. During this process, ethylene glycol molecules enter into the interlayer spaces of the swelling clays, leading to the formation of two-layer structure (∼17 A) in the case of smectites, or one-layer structure (∼14 A) in the case of vermiculites. In spite of the relatively broad literature on the understanding/characterization of ethylene glycol/water-clays complexes, the simplified structure of this complex presented by Reynolds (1965) is still used in the contemporary X-ray diffraction computer programs, which simulate structures of smectite and illite-smectite. The monolayer structure is only approximated using the assumption of the interlayer cation and ethylene glycol molecules lying in the middle of interlayer spaces. This study was therefore undertaken to investigate the structure of ethylene glycol/water-clays complex in more detail using molecular dynamics simulation. The structural models of smectites were built on the basis of pyrophyllite crystal structure (Lee and Guggenheim, 1981), with substitution of particular atoms. In most of simulations, the structural model assumed the following composition, considered as the most common in the mixed layer illite-smectites: EXCH 0.4 (Si 3.96 Al 0.04 )(Al 1.46 Fe 0.17 Mg 0.37 )O 10 (OH) 2 Atoms of the smectites were described with CLAYFF force field (Cygan et al., 2004), while atoms of water and ethylene glycol with flexible SPC and OPLS force fields, respectively. Ewald summation was used to calculate long range Coulombic interactions and the cutoff was set at 8.5 A. Results of the simulations show that in the two-layer glycolate the content of water is relatively small: up to 0.8 H 2 O per half of the smectite unit cell. Clear thermodynamic preference of mono- or two-layer structure of the complex is

  6. Electronic properties of Cs-intercalated single-walled carbon nanotubes derived from nuclear magnetic resonance

    KAUST Repository

    Abou-Hamad, E; Goze-Bac, C; Nitze, F; Schmid, M; Aznar, R; Mehring, M; Wå gberg, T

    2011-01-01

    We report on the electronic properties of Cs-intercalated single-walled carbon nanotubes (SWNTs). A detailed analysis of the 13C and 133Cs nuclear magnetic resonance (NMR) spectra reveals an increased metallization of the pristine SWNTs under Cs intercalation. The 'metallization' of CsxC materials where x=0–0.144 is evidenced from the increased local electronic density of states (DOS) n(EF) at the Fermi level of the SWNTs as determined from spin–lattice relaxation measurements. In particular, there are two distinct electronic phases called α and β and the transition between these occurs around x=0.05. The electronic DOS at the Fermi level increases monotonically at low intercalation levels x<0.05 (α-phase), whereas it reaches a plateau in the range 0.05≤x≤0.143 at high intercalation levels (β-phase). The new β-phase is accompanied by a hybridization of Cs(6s) orbitals with C(sp2) orbitals of the SWNTs. In both phases, two types of metallic nanotubes are found with a low and a high local n(EF), corresponding to different local electronic band structures of the SWNTs.

  7. Preparation of Fe-intercalated Graphite Based on Coal Tailings, Dimensional Structure

    Directory of Open Access Journals (Sweden)

    Irfan Gustian

    2015-12-01

    Full Text Available Intercalated graphite from coal tailings have been modified through the intercalation of iron. Coal tailings which is a byproduct of the destruction process and flakes washing results from mining coal. Intercalation of iron goal is to improve the physical properties of graphite and modifying sizes of crystal lattice structure with thermal method. Modification process begins with the carbonization of coal tailings at 500ºC and activated with phosphoric acid. Activation process has done by pyrolysis at 700ºC. The results of pyrolysis was soaked in mineral oil for 24 hours, then pyrolysis again with variations in temperature 800°C and 900ºC for 1 hour and subsequent intercalation iron at 1% and 2%. Material before activated, after activated, and the results of pyrolysis still indicates order nano: 29, 25 and 36 nm respectively. X-ray diffraction characterization results indicate that change in the structure, the sizes crystal lattice structure of the material The greater the concentration of iron was added, the resulting peak at 2θ = 33 and 35 also will be more sharply. The results of SEM showed different morphologies from each treatment.

  8. Synthesis and characterization of laurate-intercalated Mg–Al layered double hydroxide prepared by coprecipitation

    DEFF Research Database (Denmark)

    Gerds, Nathalie Christiane; Katiyar, Vimal; Koch, Christian Bender

    2012-01-01

    Effective utilization of layered double hydroxides (LDH) for industrial applications requires the synthesis of pure and well-defined LDH phases. In the present study, dodecanoate (laurate) anions were intercalated into Mg–Al-layered double hydroxide (LDH-C12) by coprecipitation in the presence of...

  9. Effect of friction on oxidative graphite intercalation and high-quality graphene formation.

    Science.gov (United States)

    Seiler, Steffen; Halbig, Christian E; Grote, Fabian; Rietsch, Philipp; Börrnert, Felix; Kaiser, Ute; Meyer, Bernd; Eigler, Siegfried

    2018-02-26

    Oxidative wet-chemical delamination of graphene from graphite is expected to become a scalable production method. However, the formation process of the intermediate stage-1 graphite sulfate by sulfuric acid intercalation and its subsequent oxidation are poorly understood and lattice defect formation must be avoided. Here, we demonstrate film formation of micrometer-sized graphene flakes with lattice defects down to 0.02% and visualize the carbon lattice by transmission electron microscopy at atomic resolution. Interestingly, we find that only well-ordered, highly crystalline graphite delaminates into oxo-functionalized graphene, whereas other graphite grades do not form a proper stage-1 intercalate and revert back to graphite upon hydrolysis. Ab initio molecular dynamics simulations show that ideal stacking and electronic oxidation of the graphite layers significantly reduce the friction of the moving sulfuric acid molecules, thereby facilitating intercalation. Furthermore, the evaluation of the stability of oxo-species in graphite sulfate supports an oxidation mechanism that obviates intercalation of the oxidant.

  10. Electronic properties and orbital-filling mechanism in Rb-intercalated copper phthalocyanine

    NARCIS (Netherlands)

    Evangelista, F.; Gotter, R.; Mahne, N.; Nannarone, S.; Ruocco, A.; Rudolf, P.

    2008-01-01

    The evolution of the electronic properties of a thin film of copper phthalocyanine deposited on Al(100) and progressively intercalated with rubidium atoms was followed by photoemission and X-ray absorption spectroscopies. Electron donation from the Rb atoms to the C32H16N8Cu molecules results in the

  11. Ge-intercalated graphene: The origin of the p-type to n-type transition

    KAUST Repository

    Kaloni, Thaneshwor P.; Kahaly, M. Upadhyay; Cheng, Yingchun; Schwingenschlö gl, Udo

    2012-01-01

    deposition on the surface; and iii) cluster intercalation. All other configurations under study result in p-type states irrespective of the Ge coverage. We explain the origin of the different doping states and establish the conditions under which a transition

  12. Intercalation and structural aspects of macroRAFT agents into MgAl layered double hydroxides

    Directory of Open Access Journals (Sweden)

    Dessislava Kostadinova

    2016-12-01

    Full Text Available Increasing attention has been devoted to the design of layered double hydroxide (LDH-based hybrid materials. In this work, we demonstrate the intercalation by anion exchange process of poly(acrylic acid (PAA and three different hydrophilic random copolymers of acrylic acid (AA and n-butyl acrylate (BA with molar masses ranging from 2000 to 4200 g mol−1 synthesized by reversible addition-fragmentation chain transfer (RAFT polymerization, into LDH containing magnesium(II and aluminium(III intralayer cations and nitrates as counterions (MgAl-NO3 LDH. At basic pH, the copolymer chains (macroRAFT agents carry negative charges which allowed the establishment of electrostatic interactions with the LDH interlayer and their intercalation. The resulting hybrid macroRAFT/LDH materials displayed an expanded interlamellar domain compared to pristine MgAl-NO3 LDH from 1.36 nm to 2.33 nm. Depending on the nature of the units involved into the macroRAFT copolymer (only AA or AA and BA, the intercalation led to monolayer or bilayer arrangements within the interlayer space. The macroRAFT intercalation and the molecular structure of the hybrid phases were further characterized by Fourier transform infrared (FTIR and solid-state 13C, 1H and 27Al nuclear magnetic resonance (NMR spectroscopies to get a better description of the local structure.

  13. Influence of water contamination and conductive additives on the intercalation of lithium into graphite

    Energy Technology Data Exchange (ETDEWEB)

    Joho, F; Rykart, B; Novak, P [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Spahr, M E; Monnier, A [Timcal AG, Sins (Switzerland)

    1999-08-01

    The irreversible charge loss in the first cycle of lithium intercalation into graphite electrodes for lithium-ion batteries is discussed as a function of water contamination of the electrolyte solution. Furthermore, the improvement of the electrode cycle life due to conductive additives to graphite is demonstrated. (author) 5 figs., 3 refs.

  14. Analysis and prediction of stacking sequences in intercalated lamellar vanadium phosphates

    Energy Technology Data Exchange (ETDEWEB)

    Gautier, Romain [Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS - Ecole Nationale Superieure de Chimie de Rennes (France); Centre Nationale de la Recherche Scientifique (CNRS), Institut des Materiaux Jean Rouxel (IMN), Universite de Nantes (France); Fourre, Yoann; Furet, Eric; Gautier, Regis; Le Fur, Eric [Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS - Ecole Nationale Superieure de Chimie de Rennes (France)

    2015-04-15

    An approach is presented that enables the analysis and prediction of stacking sequences in intercalated lamellar vanadium phosphates. A comparison of previously reported vanadium phosphates reveals two modes of intercalation: (i) 3d transition metal ions intercalated between VOPO{sub 4} layers and (ii) alkali/alkaline earth metal ions between VOPO{sub 4}.H{sub 2}O layers. Both intercalations were investigated using DFT calculations in order to understand the relative shifts of the vanadium phosphate layers. These calculations in addition to an analysis of the stacking sequences in previously reported materials enable the prediction of the crystal structures of M{sub x}(VOPO{sub 4}).yH{sub 2}O (M = Cs{sup +}, Cd{sup 2+} and Sn{sup 2+}). Experimental realization and structural determination of Cd(VOPO{sub 4}){sub 2}.4H{sub 2}O by single-crystal X-ray diffraction confirmed the predicted stacking sequences. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Intercalates of strontium phenylphosphonate with alcohols - Structure analysis by experimental and molecular modeling methods

    Czech Academy of Sciences Publication Activity Database

    Zima, Vítězslav; Melánová, Klára; Kovář, P.; Beneš, L.; Svoboda, Jan; Pospíšil, M.; Růžička, A.

    2015-01-01

    Roč. 2015, č. 9 (2015), s. 1552-1561 ISSN 1434-1948 R&D Projects: GA ČR(CZ) GA14-13368S Institutional support: RVO:61389013 Keywords : layered compounds * intercalation * molecular modeling Subject RIV: CA - Inorganic Chemistry Impact factor: 2.686, year: 2015

  16. Time-resolved luminescence studies in hydrogen uranyl phosphate intercalated with amines

    Energy Technology Data Exchange (ETDEWEB)

    Novo, Joao Batista Marques [Departamento de Quimica, Universidade Federal do Parana, CP 19081, 81531-990 Curitiba-PR (Brazil)]. E-mail: jbmnovo@quimica.ufpr.br; Batista, Fabio Roberto [Departamento de Quimica, Universidade Federal do Parana, CP 19081, 81531-990 Curitiba-PR (Brazil); Cunha, Carlos Jorge da [Departamento de Quimica, Universidade Federal do Parana, CP 19081, 81531-990 Curitiba-PR (Brazil); Dias, Lauro Camargo Jr. [Departamento de Quimica, Universidade Federal do Parana, CP 19081, 81531-990 Curitiba-PR (Brazil); Teixeira Pessine, Francisco Benedito [Instituto de Quimica, Universidade Estadual de Campinas, CP 6154, 13084-971 Campinas-SP (Brazil)

    2007-05-15

    Time-resolved luminescence decays of intercalated compounds of hydrogen uranyl phosphate (HUP) with p-toluidinium (HUPPT), benzylaminium (HUPBZ), {alpha}-methylbenzylaminium (HUPMBZ) and hydroxylaminium (HUPHAM) were studied. The prepared compounds belong to the tetragonal P4/ncc space group and showed 00 l reflections shifted to lower angles relative to HUP, indicating that the intercalation increases the c parameter of the unit cell. The luminescence decays of the compounds with 100% of intercalation ratio (HUPHAM and HUPBZ) were analyzed by Global Analysis, assuming Lianos' stretched exponential as the model function, which can be applied to compounds with restricted geometry and mobile donor and quencher molecules. It was remarkable that the luminescence decays showed that the quenching of the emission of the uranyl ions by the intercalated protonated amines is not restricted by low dimensionality of the host uranyl phosphate, and that a diffusion mechanism occurs. Benzylaminium cation efficiently quenches the excited energy of the uranyl ions at close distance, but the long-range and long-lifetime quenching is hindered. A different situation is found in the case of the small hydroxylaminium cation, where the long distance diffusion of the species is fast, playing an important role in the quenching of the excited uranyl ions at longer times.

  17. Time-resolved luminescence studies in hydrogen uranyl phosphate intercalated with amines

    International Nuclear Information System (INIS)

    Novo, Joao Batista Marques; Batista, Fabio Roberto; Cunha, Carlos Jorge da; Dias, Lauro Camargo Jr.; Teixeira Pessine, Francisco Benedito

    2007-01-01

    Time-resolved luminescence decays of intercalated compounds of hydrogen uranyl phosphate (HUP) with p-toluidinium (HUPPT), benzylaminium (HUPBZ), α-methylbenzylaminium (HUPMBZ) and hydroxylaminium (HUPHAM) were studied. The prepared compounds belong to the tetragonal P4/ncc space group and showed 00 l reflections shifted to lower angles relative to HUP, indicating that the intercalation increases the c parameter of the unit cell. The luminescence decays of the compounds with 100% of intercalation ratio (HUPHAM and HUPBZ) were analyzed by Global Analysis, assuming Lianos' stretched exponential as the model function, which can be applied to compounds with restricted geometry and mobile donor and quencher molecules. It was remarkable that the luminescence decays showed that the quenching of the emission of the uranyl ions by the intercalated protonated amines is not restricted by low dimensionality of the host uranyl phosphate, and that a diffusion mechanism occurs. Benzylaminium cation efficiently quenches the excited energy of the uranyl ions at close distance, but the long-range and long-lifetime quenching is hindered. A different situation is found in the case of the small hydroxylaminium cation, where the long distance diffusion of the species is fast, playing an important role in the quenching of the excited uranyl ions at longer times

  18. STUDYING THE INFLUENCE OF THE PYRENE INTERCALATOR TINA ON THE STABILITY OF DNA i-MOTIFS

    DEFF Research Database (Denmark)

    El-Sayed, Ahmed A.; Pedersen, Erik Bjerregaard; Khaireldin, Nahid A.

    2012-01-01

    Certain cytosine-rich (C-rich) DNA sequences can fold into secondary structures as four-stranded i-motifs with hemiprotonated base pairs. Here we synthesized C-rich TINA-intercalating oligonucleotides by inserting a nonnucleotide pyrene moiety between two C-rich regions. The stability of their i-...

  19. Disturbed Desmoglein-2 in the intercalated disc of pediatric patients with dilated cardiomyopathy

    NARCIS (Netherlands)

    Kessler, Elise L.; Nikkels, Peter GJ; van Veen, Toon AB

    2017-01-01

    Dilated cardiomyopathy (DCM) leads to disturbed contraction and force transduction, and is associated with substantial mortality in all age groups. Involvement of a disrupted composition of the intercalated disc (ID) has been reported. However, in children, little is established about such

  20. Synthesis, characterization, and controlled release antibacterial behavior of antibiotic intercalated Mg–Al layered double hydroxides

    International Nuclear Information System (INIS)

    Wang, Yi; Zhang, Dun

    2012-01-01

    Graphical abstract: The antibiotic anion released from Mg–Al LDHs provides a controlled release antibacterial activity against the growth of Micrococcus lysodeikticus in 3.5% NaCl solution. Highlights: ► Antibiotic anion intercalated LDHs were synthesized and characterized. ► The ion-exchange one is responsible for the release process. ► The diffusion through particle is the release rate limiting step. ► LDHs loaded with antibiotic anion have high antibacterial capabilities. -- Abstract: Antibiotic–inorganic clay composites including four antibiotic anions, namely, benzoate (BZ), succinate (SU), benzylpenicillin (BP), and ticarcillin (TC) anions, intercalated Mg–Al layered double hydroxides (LDHs) were synthesized via ion-exchange. Powder X-ray diffraction and Fourier transform infrared spectrum analyses showed the successful intercalation of antibiotic anion into the LDH interlayer. BZ and BP anions were accommodated in the interlayer region as a bilayer, whereas SU and TC anions were intercalated in a monolayer arrangement. Kinetic simulation of the release data indicated that ion-exchange was responsible for the release process, and the diffusion through the particles was the rate-limiting step. The antibacterial capabilities of LDHs loaded with antibiotic anion toward Micrococcus lysodeikticus growth were analyzed using a turbidimetric method. Significant high inhibition rate was observed when LDH nanohybrid was introduced in 3.5% NaCl solution. Therefore, this hybrid material may be applied as nanocontainer in active antifouling coating for marine equipment.

  1. Copper-mediated reductive dechlorination by green rust intercalated with dodecanoate

    DEFF Research Database (Denmark)

    Huang, Lizhi; Yin, Zhou; Cooper, Nicola G.A.

    2018-01-01

    A layered FeII-FeIII hydroxide (green rust, GR) was intercalated with dodecanoate (known as GRC12) and then amended with CuII (GRC12(Cu)) before reaction with chloroform (CF), carbon tetrachloride (CT), trichloroethylene (TCE) or tetrachloroethylene (PCE). Reduction of CT by GRC12(Cu) was 37 times...

  2. Enhancement of the fluorescence intensity of DNA intercalators using nano-imprinted 2-dimensional photonic crystal

    International Nuclear Information System (INIS)

    Endo, Tatsuro; Ueda, China; Hisamoto, Hideaki; Kajita, Hiroshi; Okuda, Norimichi; Tanaka, Satoru

    2013-01-01

    We have fabricated polymer-based 2-dimensional photonic crystals that play a key role in enhancing the fluorescence of DNA intercalators. Highly ordered 2-dimensional photonic crystals possessing triangle-shaped and nm-sized hole arrays were fabricated on a 100 μm thick polymer film using nano-imprint lithography. Samples of double-stranded DNAs (sizes: 4361 and 48502 bp; concentration: 1 pM to 10 nM) were adsorbed on the surface of the 2-dimensional photonic crystal by electrostatic interactions and then treated with intercalators. It is found that the fluorescence intensity of the intercalator is enhanced by a factor of up to 10 compared to the enhancement in the absence of the 2-dimensional photonic crystal. Fluorescence intensity increases with increasing length and concentration of the DNAs. If the 2-dimensional photonic crystal is used as a Bragg reflection mirror, the enhancement of fluorescence intensity can be easily observed using a conventional spectrofluorometer. These results suggest that the printed photonic crystal offers a great potential for highly sensitive intercalator-based fluorescent detection of DNAs. (author)

  3. Effects of pH and concentration on ability of Cl and NO to intercalate ...

    Indian Academy of Sciences (India)

    Wintec

    in solution would facilitate the anions' reactions with Mg and Al species to form HTs, resulting in a high de- gree of anion intercalation into the interlayer ... and aromatic compounds from aqueous solutions (Kameda et al 2005a, b, 2006). ..... Lazaridis N K 2003 Water Air and Soil Pollution 146 127. Lukashin A V, Kalinin S V, ...

  4. The Facile Synthesis of N-Aryl Isoxazolones as DNA Intercalators ...

    African Journals Online (AJOL)

    NICO

    2012-02-20

    Feb 20, 2012 ... Chemistry Department, Islamic Azad University, Khoy Branch, Khoy, Iran. Received 9 December 2011, revised ... These compounds have potential applications as DNA intercalators. KEYWORDS. Isoxazolones ... Isoxazolones derivatives are important heterocyclic compounds with a wide range of reported ...

  5. Selective intercalation of six ligands molecules in a self-assembled triple helix

    NARCIS (Netherlands)

    Mateos timoneda, Miguel; Kerckhoffs, J.M.C.A.; Reinhoudt, David; Crego Calama, Mercedes

    2007-01-01

    The addition of a ligand molecule to an artificial self-assembled triple helix leads to the selective intercalation of two hydrogen-bonded trimers in specific binding pockets. Furthermore, the triple helix suffers large conformational rearrangements in order to accommodate the ligand molecules in a

  6. Synthesis and characterization of a layered double hydroxide containing an intercalated nickel(II) citrate complex

    International Nuclear Information System (INIS)

    Wang Lianying; Wu Guoqing; Evans, David G.

    2007-01-01

    The nickel(II) citrate complex anion ([Ni(C 6 H 4 O 7 )] 2- ) may be intercalated into the interlayer galleries of a layered double hydroxide (LDH) host by a process involving ion-exchange with an Mg 2 Al-NO 3 LDH precursor. The powder X-ray diffraction (XRD) pattern confirms that the layered structure is maintained. The thermal decomposition process of the complex anion-intercalated material has been characterized by in situ high temperature powder XRD, thermogravimetry-differential thermal analysis (TG-DTA) and coupled with mass spectrometry (MS). The thermal stability of the nickel(II) citrate complex anion intercalated in LDHs in air is lower than that in the sodium salt. Calcination generates a high degree of nickel(II) oxide dispersion in a matrix of magnesium and aluminium oxide phases which should be an advantage if the materials are used as catalyst precursors. Based on the observed data, a structural model for the [Ni(C 6 H 4 O 7 )] 2- anion intercalated in the galleries of the LDH is proposed

  7. Synthesis, characterization and dielectric properties of polynorbornadiene–clay nanocomposites by ROMP using intercalated Ruthenium catalyst

    International Nuclear Information System (INIS)

    Yalçınkaya, Esra Evrim; Balcan, Mehmet; Güler, Çetin

    2013-01-01

    Polynorbornadiene clay nanocomposites were prepared for the first time by the ring opening metathesis polymerization (ROMP) using modified montmorillonite and polynorbornadiene the latter of which is used commonly in electric–electronic industry. The Na–MMT clay was modified by a quaternary ammonium salt containing Ruthenium complex as a suitable catalyst and intercalant as well. The norbornadiene monomers were polymerized within the modified montmorillonite layers by in-situ polymerization method in different clay loading degrees. Intercalation ability of the Ru catalyst and partially exfoliated nanocomposite structure were proved by powder X-ray Diffraction (XRD) Spectroscopy and Transmission Electron Microscopy (TEM) methods. The nanocomposite materials with high thermal degradation temperature and low dielectric constant compared to the pure polynorbornadiene were obtained. The dielectric constants decreased with the increase of the clay content. - Highlights: • Polynorbornadiene–clay nanocomposites were prepared for the first time. • Ruthenium complex was assigned as both suitable catalyst and intercalant. • The norbornadiene was polymerized by in-situ polymerization method. • Exfoliation/intercalation structures were found to be related with loading degree. • PNBD–MMT nanocomposites had a higher thermal degradation temperature and lower dielectric constant

  8. Electronic properties of Cs-intercalated single-walled carbon nanotubes derived from nuclear magnetic resonance

    KAUST Repository

    Abou-Hamad, E

    2011-05-24

    We report on the electronic properties of Cs-intercalated single-walled carbon nanotubes (SWNTs). A detailed analysis of the 13C and 133Cs nuclear magnetic resonance (NMR) spectra reveals an increased metallization of the pristine SWNTs under Cs intercalation. The \\'metallization\\' of CsxC materials where x=0–0.144 is evidenced from the increased local electronic density of states (DOS) n(EF) at the Fermi level of the SWNTs as determined from spin–lattice relaxation measurements. In particular, there are two distinct electronic phases called α and β and the transition between these occurs around x=0.05. The electronic DOS at the Fermi level increases monotonically at low intercalation levels x<0.05 (α-phase), whereas it reaches a plateau in the range 0.05≤x≤0.143 at high intercalation levels (β-phase). The new β-phase is accompanied by a hybridization of Cs(6s) orbitals with C(sp2) orbitals of the SWNTs. In both phases, two types of metallic nanotubes are found with a low and a high local n(EF), corresponding to different local electronic band structures of the SWNTs.

  9. Mechanisms of nanoclay-enhanced plastic foaming processes: effects of nanoclay intercalation and exfoliation

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Anson; Wijnands, Stephan F. L.; Kuboki, Takashi; Park, Chul B., E-mail: park@mie.utoronto.ca [University of Toronto, Microcellular Plastics Manufacturing Laboratory, Department of Mechanical and Industrial Engineering (Canada)

    2013-08-15

    The foaming behaviors of high-density polypropylene-nanoclay composites with intercalated and exfoliated nanoclay particles blown with carbon dioxide were examined via in situ observation of the foaming processes in a high-temperature/high-pressure view-cell. The intercalated nanoclay particles were 300-600 nm in length and 50-200 nm in thickness, while the exfoliated nanoclay particles were 100-200 nm in length and 1 nm in thickness. Contrary to common belief, it was discovered that intercalated nanoclay yielded higher cell density than exfoliated nanoclay despite its lower particle density. This was attributed to the higher tensile stresses generated around the larger and stiffer intercalated nanoclay particles, which led to increase in supersaturation level for cell nucleation. Also, the coupling agent used to exfoliate nanoclay would increase the affinity between polymer and surface of nanoclay particles. Consequently, the critical work needed for cell nucleation would be increased; pre-existing microvoids, which could act as seeds for cell nucleation, were also less likely to exist. Meanwhile, exfoliated nanoclay had better cell stabilization ability to prevent cell coalescence and cell coarsening. This investigation clarifies the roles of nanoclay in plastic foaming processes and provides guidance for the advancement of polymer nanocomposite foaming technology.

  10. Layered hydroxides intercalated with organic anions and their application in preparation of LDH/polymer nanocomposites

    Czech Academy of Sciences Publication Activity Database

    Kovanda, F.; Jindová, E.; Doušová, B.; Koloušek, D.; Pleštil, Josef; Sedláková, Zdeňka

    2009-01-01

    Roč. 6, č. 1 (2009), s. 111-119 ISSN 1214-9705 R&D Projects: GA AV ČR KAN100500651 Institutional research plan: CEZ:AV0Z40500505 Keywords : hydrotalcite * layered double hydroxides * intercalation Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.275, year: 2009

  11. Sythesis of rare earth metal - GIC graphite intercalation compound in molten chloride system

    International Nuclear Information System (INIS)

    Ito, Masafumi; Hagiwara, Rika; Ito, Yasuhiko

    1994-01-01

    Graphite intercalation compounds of ytterbium and neodymium have been prepared by interacting graphite and metals in molten chlorides. These rare earth metals can be suspended in molten chlorides in the presence of trichlorides via disproportionation reaction RE(0) + RE(III) = 2RE(II) at lower than 300 degC. Carbides-free compounds are obtained in these systems. (author)

  12. Impact of Infralimbic Inputs on Intercalated Amygdale Neurons: A Biophysical Modeling Study

    Science.gov (United States)

    Li, Guoshi; Amano, Taiju; Pare, Denis; Nair, Satish S.

    2011-01-01

    Intercalated (ITC) amygdala neurons regulate fear expression by controlling impulse traffic between the input (basolateral amygdala; BLA) and output (central nucleus; Ce) stations of the amygdala for conditioned fear responses. Previously, stimulation of the infralimbic (IL) cortex was found to reduce fear expression and the responsiveness of Ce…

  13. Combined experimental and theoretical investigation of interactions between kaolinite inner surface and intercalated dimethyl sulfoxide

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Shuai [School of Geoscience and Surveying Engineering, China University of Mining & Technology, Beijing 100083 (China); Liu, Qinfu, E-mail: lqf@cumtb.edu.cn [School of Geoscience and Surveying Engineering, China University of Mining & Technology, Beijing 100083 (China); Cheng, Hongfei [School of Geoscience and Surveying Engineering, China University of Mining & Technology, Beijing 100083 (China); Zeng, Fangui [Department of Earth Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China)

    2015-03-15

    Graphical abstract: Snapshot of the kaolinite–DMSO system after equilibrium is reached. - Highlights: • Dimethyl sulfoxide arranges a monolayer structure between kaolinite layers. • Weak hydrogen bonds exist between methyl groups of dimethyl sulfoxide and kaolinite silica layer. • Intercalated dimethyl sulfoxide forms strong hydrogen bonds with kaolinite alumina layer. - Abstract: Kaolinite intercalation complex with dimethyl sulfoxide (DMSO) was investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and thermogravimetry–differential scanning calorimetry (TG–DSC) combined with molecular dynamics simulation. The bands assigned to the OH stretching of inner surface of kaolinite were significantly perturbed after intercalation of DMSO into kaolinite. Additionally, the bands attributed to the vibration of gibbsite-like layers of kaolinite shifted to the lower wave number, indicating that the intercalated DMSO were strongly hydrogen bonded to the alumina octahedral surface of kaolinite. The slightly decreased intensity of 1031 cm{sup −1} and 1016 cm{sup −1} band due to the in-plane vibration of Si−O of kaolinite revealed that some DMSO molecules formed weak hydrogen bonds with the silicon tetrahedral surface of kaolinite. Based on the TG result of kaolinite–DMSO intercalation complex, the formula of A1{sub 2}Si{sub 2}O{sub 5}(OH){sub 4}(DMSO){sub 0.7} was obtained, with which the kaolinite–DMSO complex model was constructed. The molecular dynamics simulation of kaolinite–DMSO complex directly confirmed the monolayer structure of DMSO in interlayer space of kaolinite, where the DMSO arranged almost parallel with kaolinite basal surface with all methyl groups being distributed near the interlayer midplane and oxygen atoms orienting toward to the alumina octahedral surface. The radial distribution function between kaolinite and intercalated DMSO verified the strong hydrogen bonds forming between hydroxyl hydrogen

  14. Distribution of cardiac sodium channels in clusters potentiates ephaptic interactions in the intercalated disc.

    Science.gov (United States)

    Hichri, Echrak; Abriel, Hugues; Kucera, Jan P

    2018-02-15

    It has been proposed that ephaptic conduction, relying on interactions between the sodium (Na + ) current and the extracellular potential in intercalated discs, might contribute to cardiac conduction when gap junctional coupling is reduced, but this mechanism is still controversial. In intercalated discs, Na + channels form clusters near gap junction plaques, but the functional significance of these clusters has never been evaluated. In HEK cells expressing cardiac Na + channels, we show that restricting the extracellular space modulates the Na + current, as predicted by corresponding simulations accounting for ephaptic effects. In a high-resolution model of the intercalated disc, clusters of Na + channels that face each other across the intercellular cleft facilitate ephaptic impulse transmission when gap junctional coupling is reduced. Thus, our simulations reveal a functional role for the clustering of Na + channels in intercalated discs, and suggest that rearrangement of these clusters in disease may influence cardiac conduction. It has been proposed that ephaptic interactions in intercalated discs, mediated by extracellular potentials, contribute to cardiac impulse propagation when gap junctional coupling is reduced. However, experiments demonstrating ephaptic effects on the cardiac Na + current (I Na ) are scarce. Furthermore, Na + channels form clusters around gap junction plaques, but the electrophysiological significance of these clusters has never been investigated. In patch clamp experiments with HEK cells stably expressing human Na v 1.5 channels, we examined how restricting the extracellular space modulates I Na elicited by an activation protocol. In parallel, we developed a high-resolution computer model of the intercalated disc to investigate how the distribution of Na + channels influences ephaptic interactions. Approaching the HEK cells to a non-conducting obstacle always increased peak I Na at step potentials near the threshold of I Na activation

  15. Aqua complex of iron(III) and 5-chloro-3-(2-(4,4-dimethyl-2,6-dioxocyclohexylidene)hydrazinyl)-2-hydroxybenzenesulfonate: Structure and catalytic activity in Henry reaction

    Science.gov (United States)

    Mahmudov, Kamran T.; Kopylovich, Maximilian N.; Haukka, Matti; Mahmudova, Gunay S.; Esmaeila, Espandi F.; Chyragov, Famil M.; Pombeiro, Armando J. L.

    2013-09-01

    A water-soluble iron(III) complex [Fe(H2O)3(L)]·5H2O (1) was prepared by reaction of iron(III) chloride with 5-chloro-3-(2-(4,4-dimethyl-2,6-dioxocyclohexylidene)hydrazinyl)-2-hydroxy-benzenesulfonic acid (H3L). The complex was characterized by IR, 1H NMR and ESI-MS spectroscopies, elemental and X-ray crystal structural analyses. The coordination environment of the central iron(III) is a distorted octahedron, three sites being occupied by L3- ligand, which chelates in O,N,O fashion, while three other sites are filled with the water molecules. The uncoordinated water molecules are held in the channels of the overall 3D supramolecular structure by the carbonyl and sulfonyl groups of L3- and the ligated waters. Apart from the multiple hydrogen bonds, an intermolecular charge-assisted O···Cl halogen bonding with 3.044 Å distance was described. 1 acts as an effective catalyst in the Henry reaction producing nitroaldols from nitroethane and various aldehydes with yields up to 90% and threo/erythro diastereoselectivity ranging from 3:1 to 1:1.

  16. New insights into the intercalation chemistry of Al(OH)3.

    Science.gov (United States)

    Williams, Gareth R; Moorhouse, Saul J; Prior, Timothy J; Fogg, Andrew M; Rees, Nicholas H; O'Hare, Dermot

    2011-06-14

    This paper reports a number of recent developments in the intercalation chemistry of Al(OH)(3). From Rietveld refinement and solid-state NMR, it has been possible to develop a structural model for the recently reported [M(II)Al(4)(OH)(12)](NO(3))(2)·yH(2)O family of layered double hydroxides (LDHs). The M(2+) cations occupy half of the octahedral holes in the Al(OH)(3) layers, and it is thought that there is complete ordering of the metal ions while the interlayer nitrate anions are highly disordered. Filling the remainder of the octahedral holes in the layers proved impossible. While the intercalation of Li salts into Al(OH)(3) is facile, it was found that the intercalation of M(II) salts is much more capricious. Only with Co, Ni, Cu, and Zn nitrates and Zn sulfate were phase-pure LDHs produced. In other cases, there is either no reaction or a phase believed to be an LDH forms concomitantly with impurity phases. Reacting Al(OH)(3) with mixtures of M(II) salts can lead to the production of three-metal M(II)-M(II)'-Al LDHs, but it is necessary to control precisely the starting ratios of the two M(II) salts in the reaction gel because Al(OH)(3) displays selective intercalation of M nitrate (Li > Ni > Co ≈ Zn). The three-metal M(II)-M(II)'-Al LDHs exhibit facile ion exchange intercalation, which has been investigated in the first energy dispersive X-ray diffraction study of a chemical reaction system performed on Beamline I12 of the Diamond Light Source.

  17. Selective sodium intercalation into sodium nickel-manganese sulfate for dual Na-Li-ion batteries.

    Science.gov (United States)

    Marinova, Delyana M; Kukeva, Rosica R; Zhecheva, Ekaterina N; Stoyanova, Radostina K

    2018-04-26

    Double sodium transition metal sulfates combine in themselves unique intercalation properties with eco-compatible compositions - a specific feature that makes them attractive electrode materials for lithium and sodium ion batteries. Herein, we examine the intercalation properties of novel double sodium nickel-manganese sulfate, Na2Ni1/2Mn1/2(SO4)2, having a large monoclinic unit cell, through electrochemical and ex situ diffraction and spectroscopic methods. The sulfate salt Na2Ni1/2Mn1/2(SO4)2 is prepared by thermal dehydration of the corresponding hydrate salt Na2Ni1/2Mn1/2(SO4)2·4H2O having a blödite structure. The intercalation reactions on Na2Ni1-xMnx(SO4)2 are studied in two model cells: half-ion cell versus Li metal anode and full-ion cell versus Li4Ti5O12 anode by using lithium (LiPF6 dissolved in EC/DMC) and sodium electrolytes (NaPF6 dissolved in EC:DEC). Based on ex situ XRD and TEM analysis, it is found that sodium intercalation into Na2Ni1/2Mn1/2(SO4)2 takes place via phase separation into the Ni-rich monoclinic phase and Mn-rich alluaudite phase. The redox reactions involving participation of manganese and titanium ions are monitored by ex situ EPR spectroscopy. It has been demonstrated that manganese ions from the sulfate salt are participating in the electrochemical reaction, while the nickel ions remain intact. As a result, a reversible capacity of about 65 mA h g-1 is reached. The selective intercalation properties determine sodium nickel-manganese sulfate as a new electrode material for hybrid lithium-sodium ion batteries that is thought to combine the advantages of individual lithium and sodium batteries.

  18. Electrochemical lithium and sodium intercalation into the tantalum-rich layered chalcogenides Ta2Se and Ta2Te3

    International Nuclear Information System (INIS)

    Lavela, P.; Tirado, J.L.

    1999-01-01

    Two-layered tantalum chalcogenides are evaluated as alkali metal intercalation hosts in lithium and sodium electrochemical cells. The metal-rich pseudo-two-dimensional solid Ta 2 Se shows a poor intercalation behaviour. Lithium reacts with the selenide by deintercalating selenium from the blocks of Ta-related b.c.c. structure leading to a collapse of the structure and the formation of tantalum metal. Sodium is reversibly intercalated to a limited extent leading to complex structural changes in the selenide, as revealed by electron diffraction. The two-dimensional telluride Ta 2 Te 3 allows a topotactic intercalation of lithium below 1 F/mol, while a more extended reaction leads to sample amorphization. The better intercalation behaviour of this solid can be related with the one-atom thick metal layer and the van der Waals gap separating tellurium atoms of successive layers. Sodium can be reversibly intercalated into Ta 2 Te 3 in sodium cells which show a good cycling behaviour. Exposure of the intercalated solid to water vapour allows the preparation of hydrated products with a monolayer or a bilayer of water molecules solvating sodium in the interlayer space. (orig.)

  19. Measurements of quadrupolar interaction by perturbed angular correltion method on intercalated 2H-TaS sub(2)

    International Nuclear Information System (INIS)

    Saitovitch, H.

    1979-01-01

    This work is based on our quadrupolar interaction (QI) measurements on intercalated 2H-TaS sub(2) coumponds. As intercalating elements we used the alcalines - Li, Na, K, Cs -as well as the NH sub(3) (ammonia) and C sub(6) H sub(5) N (pyridine) molecules. The (QI) measurements were performed via the differential perturbed angular correlation (DPAC) technique, using Ta sup(181) as the probe isotope, on the hydrated and anhidrous phases of the intercalated systems. Our results happened to be in better agreement with the ionic model, one of the accepted models used to describe the intercalation process, as well as the transfered charges quantities and its distribution in the intercalated systems. And by its side the measured quantities, quadrupole interaction frequencies (QIF) and their distributions δ, contributed to support and to improve the ionic model. A strong charge dynamics between the 2H-TaS sub(2) sandwiches was observed and a relation between the (QIF) changes and amount of transfered charge (e sup(-)/Ta) was established. The attempt to specify the numerical contributions to the (QI) changes arriving from the different components of the 2H-TaS sub(2) intercalated systems put in evidence the probable orbitals involved in the systems bonds. Finally the kinetics of the intercalation process to form the 2H-TaS sub(2) (Li) sub(x) system was followed continuously by the (DPAC) measurements. (author)

  20. Environmentally benign graphite intercalation compound composition for exfoliated graphite, flexible graphite, and nano-scaled graphene platelets

    Science.gov (United States)

    Zhamu, Aruna; Jang, Bor Z.

    2014-06-17

    A carboxylic-intercalated graphite compound composition for the production of exfoliated graphite, flexible graphite, or nano-scaled graphene platelets. The composition comprises a layered graphite with interlayer spaces or interstices and a carboxylic acid residing in at least one of the interstices, wherein the composition is prepared by a chemical oxidation reaction which uses a combination of a carboxylic acid and hydrogen peroxide as an intercalate source. Alternatively, the composition may be prepared by an electrochemical reaction, which uses a carboxylic acid as both an electrolyte and an intercalate source. Exfoliation of the invented composition does not release undesirable chemical contaminants into air or drainage.

  1. Spectrophotometric Determination of Iron(II and Cobalt(II by Direct, Derivative, and Simultaneous Methods Using 2-Hydroxy-1-Naphthaldehyde-p-Hydroxybenzoichydrazone

    Directory of Open Access Journals (Sweden)

    V. S. Anusuya Devi

    2012-01-01

    Full Text Available Optimized and validated spectrophotometric methods have been proposed for the determination of iron and cobalt individually and simultaneously. 2-hydroxy-1-naphthaldehyde-p-hydroxybenzoichydrazone (HNAHBH reacts with iron(II and cobalt(II to form reddish-brown and yellow-coloured [Fe(II-HNAHBH] and [Co(II-HNAHBH] complexes, respectively. The maximum absorbance of these complexes was found at 405 nm and 425 nm, respectively. For [Fe(II-HNAHBH], Beer’s law is obeyed over the concentration range of 0.055–1.373 μg mL−1 with a detection limit of 0.095 μg mL−1 and molar absorptivity ɛ, 5.6 × 104 L mol−1 cm−1. [Co(II-HNAHBH] complex obeys Beer’s law in 0.118–3.534 μg mL−1 range with a detection limit of 0.04 μg mL−1 and molar absorptivity, ɛ of 2.3 × 104 L mol−1 cm−1. Highly sensitive and selective first-, second- and third-order derivative methods are described for the determination of iron and cobalt. A simultaneous second-order derivative spectrophotometric method is proposed for the determination of these metals. All the proposed methods are successfully employed in the analysis of various biological, water, and alloy samples for the determination of iron and cobalt content.

  2. Fe2(AsO4)F: A new three-dimensional condensed fluoro-arsenate iron(II) compound with antiferromagnetic interactions

    International Nuclear Information System (INIS)

    Berrocal, Teresa; Mesa, Jose L.; Pizarro, Jose L.; Urtiaga, Miren K.; Arriortua, Maria I.; Rojo, Teofilo

    2006-01-01

    Fe 2 (AsO 4 )F has been synthesized under mild hydrothermal conditions in the form of single crystals. The compound crystallizes in C2/c monoclinic space group with the unit cell parameters a=13.214(1), b=6.623(1), c=10.045(1)A and β=116.90(2) deg. with Z=8. The crystal structure consists of a three-dimensional framework constructed by two kinds of chains, A and B, with 50% of population. In the chains, the environments for the iron(II) cations show penta- and hexa-coordination. The chains establish an angle of approximately 120 deg. between them. The disordered fluoride anions in these chains given rise to [Fe(1)O 4 F(1) 0.5 (F(2) 0.5 ) 2 ] and [Fe(2)O 4 (F(1) 0.5 ) 2 F(2) 0.5 ] edge-shared polyhedra in which the fluoride anions have occupancy factors of 50% over two distinct crystallographic sites. The IR spectrum shows the characteristic bands of the (AsO 4 ) 3- groups. From the diffuse reflectance spectrum a D q parameter of 650cm -1 has been calculated for the Fe(II) d 6 high spin cation. The Mossbauer spectrum in the paramagnetic state shows a doublet that has been fitted, according to the existence of two crystallographically independent iron environments, with two Lorentzian doublets. Magnetic measurements performed between room temperature and 5K exhibit a maximum at 22.6K, characteristic of antiferromagnetic interactions with a estimated 'J'-exchange parameter of -1.2K

  3. Properties of K,Rb-intercalated C60 encapsulated inside carbon nanotubes called peapods derived from nuclear magnetic resonance

    KAUST Repository

    Mahfouz, Remi; Bouhrara, M.; Kim, Y.; Wå gberg, T.; Goze-Bac, C.; Abou-Hamad, Edy

    2015-01-01

    We present a detailed experimental study on how magnetic and electronic properties of Rb,K-intercalated C60 encapsulated inside carbon nanotubes called peapods can be derived from 13C nuclear magnetic resonance investigations. Ring currents do play

  4. Effect of adsorbed/intercalated anionic dyes into the mechanical properties of PVA: layered zinc hydroxide nitrate nanocomposites.

    Science.gov (United States)

    Marangoni, Rafael; Mikowski, Alexandre; Wypych, Fernando

    2010-11-15

    Zinc hydroxide nitrate (ZHN) was adsorbed with anions of blue dyes (Chicago sky blue, CSB; Evans blue, EB; and Niagara blue, NB) and intercalated with anions of orange dyes (Orange G, OG; Orange II, OII; methyl orange, MO). Transparent, homogeneous and colored nanocomposite films were obtained by casting after dispersing the pigments (dye-intercalated/adsorbed into LHSs) into commercial poly(vinyl alcohol) (PVA). The films were characterized by XRD, UV-Vis spectroscopy, and mechanical testing. The mechanical properties of the PVA compounded with the dye-intercalated/adsorbed ZHN were evaluated, and reasonable increases in Young's modulus and ultimate tensile strength were observed, depending on the amount and choice of layered filler. These results demonstrate the possibility of using a new class of layered hydroxide salts intercalated and adsorbed with anionic dyes to prepare multifunctional polymer nanocomposite materials. Copyright © 2010 Elsevier Inc. All rights reserved.

  5. A new oxidimetric reagent: potassium dichromate in a strong phosphoric acid medium--VII. Photometric titration of vanadium(IV) and of cerium(III) alone and in mixtures with iroN(II).

    Science.gov (United States)

    Rao, G G; Rao, P K

    1967-01-01

    Vanadium(IV) can be accurately titrated with potassium dichromate in media containing phosphoric acid of 3-12M concentration: the change in absorption of vanadium(IV) is followed in the region 660 mmicro using a red filter. It is more convenient to carry out the titration in 3M phosphoric acid because at higher concentrations chloride, nitrate, cerium(III) and manganese(II) may interfere. Photoelcetric titration is more convenient than potentiometric because the former can be made in a 3M phosphoric acid medium, whereas the latter is possible only in 12M phosphoric acid. The simultaneous differential photometric titration of iron(II) and vanadium(IV) is also possible. Conditions have been found for the photometric titration of cerium(III) and of cerium(III) plus iron(II). The titration is carried out (at 450 mmicro or with a blue filter) in about 10.5M phosphoric acid. Application of the method to a cerium mineral is considered.

  6. Biosorption of copper(II), lead(II), iron(III) and cobalt(II) on Bacillus sphaericus-loaded Diaion SP-850 resin

    International Nuclear Information System (INIS)

    Tuzen, Mustafa; Uluozlu, Ozgur Dogan; Usta, Canan; Soylak, Mustafa

    2007-01-01

    The biosorption of copper(II), lead(II), iron(III) and cobalt(II) on Bacillus sphaericus-loaded Diaion SP-850 resin for preconcentration-separation of them have been investigated. The sorbed analytes on biosorbent were eluted by using 1 mol L -1 HCl and analytes were determined by flame atomic absorption spectrometry. The influences of analytical parameters including amounts of pH, B. sphaericus, sample volume etc. on the quantitative recoveries of analytes were investigated. The effects of alkaline, earth alkaline ions and some metal ions on the retentions of the analytes on the biosorbent were also examined. Separation and preconcentration of Cu, Pb, Fe and Co ions from real samples was achieved quantitatively. The detection limits by 3 sigma for analyte ions were in the range of 0.20-0.75 μg L -1 for aqueous samples and in the range of 2.5-9.4 ng g -1 for solid samples. The validation of the procedure was performed by the analysis of the certified standard reference materials (NRCC-SLRS 4 Riverine Water, SRM 2711 Montana soil and GBW 07605 Tea). The presented method was applied to the determination of analyte ions in green tea, black tea, cultivated mushroom, boiled wheat, rice and soil samples with successfully results

  7. Preparation and characterization of iron(III) {sup 99}Mo-molybdate(VI) gels for the assessment of {sup 99m}Tc elution performance

    Energy Technology Data Exchange (ETDEWEB)

    Amin, Mahmoud; Fasih, Tharwat W.; El-Absy, Mohamed A. [Egyptian Atomic Energy Authority, Cairo (Egypt)

    2018-04-01

    New iron(III) {sup 99}Mo-molybdate(VI) gels (Fe{sup 99}Mo) of high Mo content were prepared by the precipitation/filtration method. {sup 99}Mo-MoO{sub 3} dissolved in NaOH was added to aqueous solutions of Fe(NO{sub 3}){sub 3} at Mo/Fe mole fractions ∝2.21 and 1.99 with continuous stirring at ambient room temperature. Two different Fe{sup 99}Mo were precipitated from the mixed solutions adjusted at pH 2 and 4.7. The amount of water of hydration increased with the increasing the gel settling time and pH of the mixed solution. The matrices were characterized by radiometric, XRD, SEM, XRF, FT-IR, TGA, and DTA measurements. Small chromatographic columns of 2.0 g Fe{sup 99}Mo containing ≥800 mg Mo tagged with 740 MBq {sup 99}Mo were eluted with 5 mL saline solution. Highly reproducible {sup 99m}Tc elution indices suitable for preparation of {sup 99}Mo/{sup 99m}Tc generators were achieved from generator supported with 0.5 g Al{sub 2}O{sub 3} filter. Elution performance of {sup 99m}Tc radionuclide was highly dependent on the gel structural properties.

  8. Preparation and characterization of iron(III) 99Mo-molybdate(VI) gels for the assessment of 99mTc elution performance

    International Nuclear Information System (INIS)

    Amin, Mahmoud; Fasih, Tharwat W.; El-Absy, Mohamed A.

    2018-01-01

    New iron(III) 99 Mo-molybdate(VI) gels (Fe 99 Mo) of high Mo content were prepared by the precipitation/filtration method. 99 Mo-MoO 3 dissolved in NaOH was added to aqueous solutions of Fe(NO 3 ) 3 at Mo/Fe mole fractions ∝2.21 and 1.99 with continuous stirring at ambient room temperature. Two different Fe 99 Mo were precipitated from the mixed solutions adjusted at pH 2 and 4.7. The amount of water of hydration increased with the increasing the gel settling time and pH of the mixed solution. The matrices were characterized by radiometric, XRD, SEM, XRF, FT-IR, TGA, and DTA measurements. Small chromatographic columns of 2.0 g Fe 99 Mo containing ≥800 mg Mo tagged with 740 MBq 99 Mo were eluted with 5 mL saline solution. Highly reproducible 99m Tc elution indices suitable for preparation of 99 Mo/ 99m Tc generators were achieved from generator supported with 0.5 g Al 2 O 3 filter. Elution performance of 99m Tc radionuclide was highly dependent on the gel structural properties.

  9. The ground states of iron(III) porphines: Role of entropy–enthalpy compensation, Fermi correlation, dispersion, and zero-point energies

    DEFF Research Database (Denmark)

    Kepp, Kasper Planeta

    2011-01-01

    on calculations of five iron(III) porphines. Here, we compute the geometries of 80 different electronic configurations and the free energies of the most stable configurations with the functionals TPSSh, TPSS, and B3LYP. Zero-point energies and entropy favor high-spin by ~4kJ/mol and 0–10kJ/mol, respectively. When...... favors low-spin by 3–53kJ/mol (TPSSh) or 4–15kJ/mol (B3LYP) due to the attractive r−6 term and the shorter distances in low-spin. The very large and diverse corrections from TPSS and TPSSh seem less consistent with the similarity of the systems than when calculated from B3LYP. If the functional......-specific corrections are used, B3LYP and TPSSh are of equal accuracy, and TPSS is much worse, whereas if the physically reasonable B3LYP-computed dispersion effect is used for all functionals, TPSSh is accurate for all systems. B3LYP is significantly more accurate when dispersion is added, confirming previous results....

  10. Synthesis and characterization of μ-hydroxido- and μ-polycarboxylato-bridged iron(III complexes with 2,2’-bipyridine

    Directory of Open Access Journals (Sweden)

    Tasić Nikola

    2014-01-01

    Full Text Available Four novel polymeric iron(III complexes with 2,2’-bipyridine (bipy and different aromatic polycarboxylato ligands as anions of phthalic (pht, isophthalic (ipht, terephthalic (tpht and pyromellitic (pyr acid were synthesized by ligand exchange reaction. The complexes were characterized by elemental and TG/DSC analysis, FTIR and diffuse reflectance UV-VIS-NIR spectroscopy and magnetic susceptibility measurements. Based on analytical and spectral data the formulae of the complexes are {[Fe4(bipy2 (H2O2(OH6(pht3]•2H2O}n (1, {[Fe4(bipy2(Hipht2(ipht2(OH6]•4H2O}n (2, {[Fe4(bipy2(Htpht2(OH6(tpht2]•4H2O}n (3 and {[Fe4(bipy(H2O8(OH4 (pyr2]•H2O}n (4. All complexes are red brown and low-spin with a distorted octahedral geometry and FeO6 or FeN2O4 chromophore. Polycarboxylato ligands have a bridging role in all cases, whereas monodentate COO groups are present in 2 and 3, bridging and chelate COO groups are established in 1 and 4. The thermal behaviour of 1-4 was investigated in detail and the molar dehydration enthalpies were calculated. According to the all those results, the structural formulae of the complexes 1-4 were proposed. [Projekat Ministarstva nauke Republike Srbije, br. III45007

  11. Modification and intercalation of layered zirconium phosphates: a solid-state NMR monitoring.

    Science.gov (United States)

    Bakhmutov, Vladimir I; Kan, Yuwei; Sheikh, Javeed Ahmad; González-Villegas, Julissa; Colón, Jorge L; Clearfield, Abraham

    2017-07-01

    Several layered zirconium phosphates treated with Zr(IV) ions, modified by monomethoxy-polyethyleneglycol-monophosphate and intercalated with doxorubicin hydrochloride have been studied by solid-state MAS NMR techniques. The organic components of the phosphates have been characterized by the 13 C{ 1 H} CP MAS NMR spectra compared with those of initial compounds. The multinuclear NMR monitoring has provided to establish structure and covalent attachment of organic/inorganic moieties to the surface and interlayer spaces of the phosphates. The MAS NMR experiments including kinetics of proton-phosphorus cross polarization have resulted in an unusual structure of zirconium phosphate 6 combining decoration of the phosphate surface by polymer units and their partial intercalation into the interlayer space. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  12. 10th International School of Materials Science and Technology : Intercalation in Layered Materials "Ettore Majorana"

    CERN Document Server

    1986-01-01

    This volume is prepared from lecture notes for the course "Intercalation in Layered Materials" which was held at the Ettore Majorana Centre for Scientific Culture at Erice, Sicily in July, 1986, as part of the International School of Materials Science and Tech­ nology. The course itself consisted of formal tutorial lectures, workshops, and informal discussions. Lecture notes were prepared for the formal lectures, and short summaries of many of the workshop presentations were prepared. This volume is based on these lecture notes and research summaries. The material is addressed to advanced graduate students and postdoctoral researchers and assumes a background in basic solid state physics. The goals of this volume on Intercalation in Layered Materials include an introduc­ tion to the field for potential new participants, an in-depth and broad exposure for stu­ dents and young investigators already working in the field, a basis for cross-fertilization between workers on various layered host materials...

  13. Three-dimensional metal-intercalated covalent organic frameworks for near-ambient energy storage

    Science.gov (United States)

    Gao, Fei; Ding, Zijing; Meng, Sheng

    2013-01-01

    A new form of nanoporous material, metal intercalated covalent organic framework (MCOF) is proposed and its energy storage property revealed. Employing density functional and thermodynamical analysis, we find that stable, chemically active, porous materials could form by stacking covalent organic framework (COF) layers with metals as a gluing agent. Metal acts as active sites, while its aggregation is suppressed by a binding energy significantly larger than the corresponding cohesive energy of bulk metals. Two important parameters, metal binding and metal-metal separation, are tuned by selecting suitable building blocks and linkers when constructing COF layers. Systematic searches among a variety of elements and organic molecules identify Ca-intercalated COF with diphenylethyne units as optimal material for H2 storage, reaching a striking gravimetric density ~ 5 wt% at near-ambient conditions (300 K, 20 bar), in comparison to < 0.1 wt% for bare COF-1 under the same condition. PMID:23698018

  14. Synthesis and characterization of intercalated polyaniline-clay nanocomposite using supercritical CO2

    Science.gov (United States)

    Abdelraheem, A.; El-Shazly, A. H.; Elkady, M. F.

    2018-05-01

    Lately, supercritical CO2 (SCCO2) have been getting great interest. It can be used in numerous applications because it is environmentally friendly, safe, comparatively low cost, and nonflammable. One of its applications is being a solvent in the synthesis of polymeric-clay nanocomposite. In this paper, intercalated polyaniline-clay nanocomposite (PANC) was prepared using SCCO2. The intercalation structure of polyaniline chains between clay layers was verified by various characterization techniques. Scanning electron microscope and transmission electron microscope (SEM-TEM) were used to show the morphology of the synthesized nanocomposite. The molecular structure of PANC nanocomposite was confirmed using Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The BET surface area and the conductivity of the nanocomposite were determined.

  15. Metallization and superconductivity in Ca-intercalated bilayer MoS2

    Science.gov (United States)

    Szczȱśniak, R.; Durajski, A. P.; Jarosik, M. W.

    2017-12-01

    A two-dimensional molybdenum disulfide (MoS2) has attracted significant interest recently due to its outstanding physical, chemical and optoelectronic properties. In this paper, using the first-principles calculations, the dynamical stability, electronic structure and superconducting properties of Ca-intercalated bilayer MoS2 are investigated. The calculated electron-phonon coupling constant implies that the stable form of investigated system is a strong-coupling superconductor (λ = 1.05) with a low value of critical temperature (TC = 13.3 K). Moreover, results obtained within the framework of the isotropic Migdal-Eliashberg formalism proved that Ca-intercalated bilayer MoS2 exhibits behavior that goes beyond the scope of the conventional BCS theory.

  16. Bifunctional rhodium intercalator conjugates as mismatch-directing DNA alkylating agents.

    Science.gov (United States)

    Schatzschneider, Ulrich; Barton, Jacqueline K

    2004-07-21

    A conjugate of a DNA mismatch-specific rhodium intercalator, containing the bulky chrysenediimine ligand, and an aniline mustard has been prepared, and targeting of mismatches in DNA by this conjugate has been examined. The preferential alkylation of mismatched over fully matched DNA is found by a mobility shift assay at concentrations where untethered organic mustards show little reaction. The binding site of the Rh intercalator was determined by DNA photocleavage, and the position of covalent modification was established on the basis of the enhanced depurination associated with N-alkylation. The site-selective alkylation at mismatched DNA renders these conjugates useful tools for the covalent tagging of DNA base pair mismatches and new chemotherapeutic design.

  17. Synchrotron-Radiation X-Ray Investigation of Li+/Na+ Intercalation into Prussian Blue Analogues

    Directory of Open Access Journals (Sweden)

    Yutaka Moritomo

    2013-01-01

    Full Text Available Prussian blue analogies (PBAs are promising cathode materials for lithium ion (LIB and sodium ion (SIB secondary batteries, reflecting their covalent and nanoporous host structure. With use of synchrotron-radiation (SR X-ray source, we investigated the structural and electronic responses of the host framework of PBAs against Li+ and Na+ intercalation by means of the X-ray powder diffraction (XRD and X-ray absorption spectroscopy (XAS. The structural investigation reveals a robust nature of the host framework against Li+ and Na+ intercalation, which is advantageous for the stability and lifetime of the batteries. The spectroscopic investigation identifies the redox processes in respective plateaus in the discharge curves. We further compare these characteristics with those of the conventional cathode materials, such as, LiCoO2, LiFePO4, and LiMn2O4.

  18. Origin of the high p-doping in F intercalated graphene on SiC

    KAUST Repository

    Cheng, Yingchun

    2011-08-04

    The atomic and electronic structures of F intercalated epitaxialgraphene on a SiC(0001) substrate are studied by first-principles calculations. A three-step fluorination process is proposed. First, F atoms are intercalated between the graphene and the SiC, which restores the Dirac point in the band structure. Second, saturation of the topmost Si dangling bonds introduces p-doping up to 0.37 eV. Third, F atoms bond covalently to the graphene to enhance the p-doping. Our model explains the highly p-doped state of graphene on SiC after fluorination [A. L. Walter et al., Appl. Phys. Lett. 98, 184102 (2011)].

  19. Silicene on Monolayer PtSe2: From Strong to Weak Binding via NH3 Intercalation

    KAUST Repository

    Sattar, Shahid; Singh, Nirpendra; Schwingenschlö gl, Udo

    2018-01-01

    We study the properties of silicene on monolayer PtSe2 by first-principles calculations and demonstrate a much stronger interlayer interaction than previously reported for silicene on other semiconducting substrates. This fact opens the possibility of a direct growth. A band gap of 165 meV results from inversion symmetry breaking and large spin-splittings in the valence and conduction bands from proximity to monolayer PtSe2 and its strong spin–orbit coupling. It is also shown that the interlayer interaction can be effectively reduced by intercalating NH3 molecules between silicene and monolayer PtSe2 without inducing charge transfer or defect states near the Fermi energy. A small NH3 diffusion barrier makes intercalation a viable experimental approach to control the interlayer interaction.

  20. Preparation and intercalation study of ternary transition elements chalcogenides AxMXn

    International Nuclear Information System (INIS)

    Kassem, M.

    1999-01-01

    The crystalline powders of transition elements chalcogenides have been prepared by solid-solid reaction method starting from elemental powders in evacuated and sealed quartz tubes heated at various temperatures depending on the compound to be prepared. The structures and composition of the obtained compounds have been studied by X-ray diffraction and X-ray fluorescence techniques. Intercalation compounds Co x MX 2 have been obtained by heating the powder with elemental cobalt at 500 Centigrade. The results of the structural studies show that the intercalation of cobalt is a regular phenomena and the cobalt atoms play the role of staples for the layers constructing the crystalline structure of starting materials. This stapling phenomena is accompanied by changes in distance between the layers and therefore changes in the length of bonds between the elements of compound. The changes in the length of bonds have been confirmed by the results of FTIR studies.(author)

  1. Silicene on Monolayer PtSe2: From Strong to Weak Binding via NH3 Intercalation

    KAUST Repository

    Sattar, Shahid

    2018-01-16

    We study the properties of silicene on monolayer PtSe2 by first-principles calculations and demonstrate a much stronger interlayer interaction than previously reported for silicene on other semiconducting substrates. This fact opens the possibility of a direct growth. A band gap of 165 meV results from inversion symmetry breaking and large spin-splittings in the valence and conduction bands from proximity to monolayer PtSe2 and its strong spin–orbit coupling. It is also shown that the interlayer interaction can be effectively reduced by intercalating NH3 molecules between silicene and monolayer PtSe2 without inducing charge transfer or defect states near the Fermi energy. A small NH3 diffusion barrier makes intercalation a viable experimental approach to control the interlayer interaction.

  2. High surface area V-Mo-N materials synthesized from amine intercalated foams

    International Nuclear Information System (INIS)

    Krawiec, Piotr; Narayan Panda, Rabi; Kockrick, Emanuel; Geiger, Dorin; Kaskel, Stefan

    2008-01-01

    Nanocrystalline ternary V-Mo nitrides were prepared via nitridation of amine intercalated oxide foams or bulk ternary oxides. Specific surface areas were in the range between 40 and 198 m 2 g -1 and strongly depended on the preparation method (foam or bulk oxide). Foamed precursors were favorable for vanadium rich materials, while for molybdenum rich samples bulk ternary oxides resulted in higher specific surface areas. The materials were characterized via nitrogen physisorption at 77 K, X-ray diffraction patterns, electron microscopy, and elemental analysis. - Graphical abstract: Nanocrystalline ternary V-Mo nitrides were prepared via nitridation of amine intercalated oxide foams or bulk ternary oxides. Foamed precursors were favorable for vanadium rich materials, while for molybdenum rich samples bulk ternary oxides resulted in higher specific surface areas

  3. Pseudo Dirac dispersion in Mn-intercalated graphene on SiC

    KAUST Repository

    Kahaly, M. Upadhyay

    2013-07-01

    The atomic and electronic structures of bulk C6Mn, bulk C 8Mn, and Mn-intercalated graphene on SiC(0 0 0 1) and SiC(0001̄) are investigated by density functional theory. We find for both configurations of Mn-intercalated graphene a nonmagnetic state, in agreement with the experimental situation for SiC(0 0 0 1), and explain this property. The electronic structures around the Fermi energy are dominated by Dirac-like cones at energies consistent with data from angular resolved photoelectron spectroscopy [Gao et al., ACS Nano. 6 (2012) 6562]. However, our results demonstrate that the corresponding states trace back to hybridized Mn d orbitals, and not to the graphene. © 2013 Elsevier B.V. All rights reserved.

  4. Pseudo Dirac dispersion in Mn-intercalated graphene on SiC

    KAUST Repository

    Kahaly, M. Upadhyay; Kaloni, Thaneshwor P.; Schwingenschlö gl, Udo

    2013-01-01

    The atomic and electronic structures of bulk C6Mn, bulk C 8Mn, and Mn-intercalated graphene on SiC(0 0 0 1) and SiC(0001̄) are investigated by density functional theory. We find for both configurations of Mn-intercalated graphene a nonmagnetic state, in agreement with the experimental situation for SiC(0 0 0 1), and explain this property. The electronic structures around the Fermi energy are dominated by Dirac-like cones at energies consistent with data from angular resolved photoelectron spectroscopy [Gao et al., ACS Nano. 6 (2012) 6562]. However, our results demonstrate that the corresponding states trace back to hybridized Mn d orbitals, and not to the graphene. © 2013 Elsevier B.V. All rights reserved.

  5. Intercalation behavior of amino acids into Zn-Al-layered double hydroxide by calcination-rehydration reaction

    International Nuclear Information System (INIS)

    Aisawa, Sumio; Kudo, Hiroko; Hoshi, Tomomi; Takahashi, Satoshi; Hirahara, Hidetoshi; Umetsu, Yoshio; Narita, Eiichi

    2004-01-01

    The intercalation of amino acids for the Zn-Al-layered double hydroxide (LDH) has been investigated by the calcination-rehydration reaction at 298K using mainly phenylalanine (Phe) as a guest amino acid. The Zn-Al oxide precursor prepared by the calcination of Zn-Al-carbonated LDH at 773K for 2h was used as the host material. The amount of Phe intercalated by the rehydration was remarkably influenced by the initial solution pH and reached ca. 2.7 times for anion exchange capacity (AEC) of the LDH at neutral and weak alkaline solutions, suggesting that Phe was intercalated as amphoteric ion form into the LDH interlayer. As Phe is intercalated for the LDH as monovalent anion in alkaline solution, the amount of Phe intercalated at pH 10.5 corresponded with AEC of the LDH. The solid products were found to have the expanded LDH structure, which confirmed that Phe was intercalated into the LDH interlayer as amphoteric ion or anion form. The basal spacing, d 003 , of the Phe/LDH was 1.58nm at pH 7.0 and 0.80nm at pH 10.5; two kinds of expansion suggested for Phe in the interlayer space as vertical (pH 7.0) and horizontal (pH 10.5) orientations. The intercalation behavior of various amino acids for the LDH was also found to be greatly influenced by the feature of the amino acid side-chain, namely, its carbon-chain length, structure and physicochemical property. In particular, α-amino acids possessing a hydrophobic or negative-charged side-chain were preferentially intercalated for the LDH

  6. Electrochemical potassium-ion intercalation in NaxCoO2: a novel cathode material for potassium-ion batteries.

    Science.gov (United States)

    Sada, Krishnakanth; Senthilkumar, Baskar; Barpanda, Prabeer

    2017-07-27

    Reversible electrochemical potassium-ion intercalation in P2-type Na x CoO 2 was examined for the first time. Hexagonal Na 0.84 CoO 2 platelets prepared by a solution combustion synthesis technique were found to work as an efficient host for K + intercalation. They deliver a high reversible capacity of 82 mA h g -1 , good rate capability and excellent cycling performance up to 50 cycles.

  7. Classifying the mechanisms of electrochemical shock in ion-intercalation materials

    OpenAIRE

    Woodford, William; Carter, W. Craig; Chiang, Yet-Ming

    2014-01-01

    “Electrochemical shock” – the electrochemical cycling-induced fracture of materials – contributes to impedance growth and performance degradation in ion-intercalation batteries, such as lithium-ion. Using a combination of micromechanical models and acoustic emission experiments, the mechanisms of electrochemical shock are identified, classified, and modeled in targeted model systems with different composition and microstructure. A particular emphasis is placed on mechanical degradation occurr...

  8. Superconductivity in intercalated and substituted Y2Br2C2

    International Nuclear Information System (INIS)

    Baecker, M.; Simon, A.; Kremer, R.K.; Mattausch, H.J.; Dronskowski, R.; Rouxel, J.

    1996-01-01

    Layer compounds of the type Y 2 X 2 C 2 (X=Cl, Br, I) show superconductivity at temperatures between 2.3 and 11.2 K. The transition temperature is related to the tendency of conduction electrons toward pairwise localization in C 2 -π * states at the Fermi level, and changes with the concentration of valence electrons, which is varied by intercalation of Na. (orig.)

  9. Histological study of human sublingual gland with special emphasis on intercalated and striated ducts

    International Nuclear Information System (INIS)

    Rana, R.; Minhas, L.A.; Mubarik, A.

    2012-01-01

    Objective: To study the histomorphological characteristics of human sublingual gland, specially of intercalated and striated ducts. Study design: Descriptive study Place and duration of study: Army Medical College from Jan 2002 to Dec 2002 Materials and methods: Fifteen sublingual glands (right and left) from postmortem cases were obtained from District Headquarter Hospital Rawalpindi, within twelve hours of death. Five micrometer thick sections were made and stained with Haematoxylin and Eosin (H and E). Morphology of intercalated and striated ducts was studied and their number was counted. Results: The mean number of intercalated ducts in the right gland 'a'and 'b' parts, and in the left gland 'a' and 'b' parts was 1.45+-0.14, 1.39+-.009, 1.31+-0.11 and 1.18+-0.10 respectively. The mean diameter of intercalated ducts in the same parts was 19.76+-0.44 micro m, 20.6+-0.53 micro m, 20.34+-0.49 micro m and 19.84+-0.98 micro m respectively. The mean number of striated ducts in the right gland ''a'' and ''b'' parts, and in the left gland ''a'' and ''b'' parts was 0.55+-.008, 0.57+-.008, 0.80+-0.14 and 0.80+-0.14 while mean diameter of striated ducts in the right gland ''a'' and ''b'' parts, and in the left gland ''a'' and ''b'' parts was 49.90+-4.70 micro m, 53.23+-2.50 micro m, 61.68+-3.93 micro m and 57.73+-2.85 micro m respectively. Conclusion: The difference between the mean number and diameter of the ducts of right and left glands was statistically insignificant. (author)

  10. Enhanced electron-lattice coupling under uniaxial stress in layered double hydroxides intercalated with samarium complexes

    International Nuclear Information System (INIS)

    Park, Ta-Ryeong

    2004-01-01

    We have applied uniaxial stress to samarium complexes by intercalating them into the gallery of a layered material and by using a diamond-anvil cell at 28 K. Although uniaxial stress reduces symmetry and removes degeneracy, the overall number of photoluminescence (PL) peaks evidently decreased with the application of uniaxial stress. This contradictory observation is explained by an increased electron-lattice coupling strength under uniaxial stress. This behavior is also confirmed by time-resolved PL data.

  11. Ultrahigh intercalation pseudocapacitance of mesoporous orthorhombic niobium pentoxide from a novel cellulose nanocrystal template

    International Nuclear Information System (INIS)

    Kong, Lingping; Zhang, Chuangfang; Wang, Jitong; Long, Donghui; Qiao, Wenming; Ling, Licheng

    2015-01-01

    A facile biotemplating method has been developed to prepare mesoporous orthorhombic nobium pentoxide (T-Nb 2 O 5 ) films with ultrahigh lithium ion (Li + ) intercalation pseudocapacitance. Nanorod-like cellulose nanocrystals (CNs) with 5–10 nm in width and 100–300 nm in length are produced by the hydrolysis of cotton, which can serve as a novel soft templating agent enabling the straightforward synthesis of mesoporous T-Nb 2 O 5 films. By varying the niobic-to-template ratio, it is possible to tune the surface area and crystallite dimension of the Nb 2 O 5 films. The obtained T-Nb 2 O 5 films show typical capacitive-dominated behaviour in the sweep rate range of 1–20 mV s −1 . It delivers an initial intercalation capacity of 644 C g −1 at a current density of 0.625 A g −1 , corresponding to x = 1.83 for Li x Nb 2 O 5 , and can still keep relatively stable capacity of 560 C g −1 after 300 cycles. Moreover, its excellent high-rate capability (450 C g −1 at 12.5 A g −1 ) and wider temperature adaptability present here suggests the promising of T-Nb 2 O 5 as high-energy pseudocapacitor electrode with superior intercalation capacitive behaviour. - Graphical abstract: We developed a facile and sustainable method to prepare T-Nb 2 O 5 nanocrystals using novel nanorod-like cellulose nanocrystals (CNs) as soft templates. The T-Nb 2 O 5 nanocrystals exhibited unprecedented Li + intercalation pseudocapacitance, excellent cycle performance and good high-and-low temperature tolerance performance.

  12. Voreloxin is an anticancer quinolone derivative that intercalates DNA and poisons topoisomerase II.

    Directory of Open Access Journals (Sweden)

    Rachael E Hawtin

    2010-04-01

    Full Text Available Topoisomerase II is critical for DNA replication, transcription and chromosome segregation and is a well validated target of anti-neoplastic drugs including the anthracyclines and epipodophyllotoxins. However, these drugs are limited by common tumor resistance mechanisms and side-effect profiles. Novel topoisomerase II-targeting agents may benefit patients who prove resistant to currently available topoisomerase II-targeting drugs or encounter unacceptable toxicities. Voreloxin is an anticancer quinolone derivative, a chemical scaffold not used previously for cancer treatment. Voreloxin is completing Phase 2 clinical trials in acute myeloid leukemia and platinum-resistant ovarian cancer. This study defined voreloxin's anticancer mechanism of action as a critical component of rational clinical development informed by translational research.Biochemical and cell-based studies established that voreloxin intercalates DNA and poisons topoisomerase II, causing DNA double-strand breaks, G2 arrest, and apoptosis. Voreloxin is differentiated both structurally and mechanistically from other topoisomerase II poisons currently in use as chemotherapeutics. In cell-based studies, voreloxin poisoned topoisomerase II and caused dose-dependent, site-selective DNA fragmentation analogous to that of quinolone antibacterials in prokaryotes; in contrast etoposide, the nonintercalating epipodophyllotoxin topoisomerase II poison, caused extensive DNA fragmentation. Etoposide's activity was highly dependent on topoisomerase II while voreloxin and the intercalating anthracycline topoisomerase II poison, doxorubicin, had comparable dependence on this enzyme for inducing G2 arrest. Mechanistic interrogation with voreloxin analogs revealed that intercalation is required for voreloxin's activity; a nonintercalating analog did not inhibit proliferation or induce G2 arrest, while an analog with enhanced intercalation was 9.5-fold more potent.As a first-in-class anticancer

  13. Retention of contaminants Cd and Hg adsorbed and intercalated in aluminosilicate clays: A first principles study

    Science.gov (United States)

    Crasto de Lima, F. D.; Miwa, R. H.; Miranda, Caetano R.

    2017-11-01

    Layered clay materials have been used to incorporate transition metal (TM) contaminants. Based on first-principles calculations, we have examined the energetic stability and the electronic properties due to the incorporation of Cd and Hg in layered clay materials, kaolinite (KAO) and pyrophyllite (PYR). The TM can be (i) adsorbed on the clay surface as well as (ii) intercalated between the clay layers. For the intercalated case, the contaminant incorporation rate can be optimized by controlling the interlayer spacing of the clay, namely, pillared clays. Our total energy results reveal that the incorporation of the TMs can be maximized through a suitable tuning of vertical distance between the clay layers. Based on the calculated TM/clay binding energies and the Langmuir absorption model, we estimate the concentrations of the TMs. Further kinetic properties have been examined by calculating the activation energies, where we found energy barriers of ˜20 and ˜130 meV for adsorbed and intercalated cases, respectively. The adsorption and intercalation of ionized TM adatoms were also considered within the deprotonated KAO surface. This also leads to an optimal interlayer distance which maximizes the TM incorporation rate. By mapping the total charge transfers at the TM/clay interface, we identify a net electronic charge transfer from the TM adatoms to the topmost clay surface layer. The effect of such a charge transfer on the electronic structure of the clay (host) has been examined through a set of X-ray absorption near edge structure (XANES) simulations, characterizing the changes of the XANES spectra upon the presence of the contaminants. Finally, for the pillared clays, we quantify the Cd and Hg K-edge energy shifts of the TMs as a function of the interlayer distance between the clay layers and the Al K-edge spectra for the pristine and pillared clays.

  14. Layered Zinc Hydroxide Salts Intercalated with Anionic Surfactants and Adsolubilized with UV Absorbing Organic Molecules

    OpenAIRE

    Cursino,Ana C. T.; Rives,Vicente; Carlos,Luís D.; Rocha,João; Wypych,Fernando

    2015-01-01

    Two anionic surfactants, dodecylsulfate (DDS) and dodecylbenzenesulfonate (DBS), were intercalated into layered zinc hydroxide salts (LHS) using the direct alkaline co-precipitation method, and characterized by powder X-ray diffraction (PXRD), Fourier-transform infrared (FTIR) and thermogravimetric analysis/differential thermal analysis (TGA/DTA). Different UV-absorbing organic molecules, like salicylates, cinnamates and benzophenones, were adsolubilized in the LHS interlayer following two di...

  15. Work Function Characterization of Potassium-Intercalated, Boron Nitride Doped Graphitic Petals

    Directory of Open Access Journals (Sweden)

    Patrick T. McCarthy

    2017-07-01

    Full Text Available This paper reports on characterization techniques for electron emission from potassium-intercalated boron nitride-modified graphitic petals (GPs. Carbon-based materials offer potentially good performance in electron emission applications owing to high thermal stability and a wide range of nanostructures that increase emission current via field enhancement. Furthermore, potassium adsorption and intercalation of carbon-based nanoscale emitters decreases work functions from approximately 4.6 eV to as low as 2.0 eV. In this study, boron nitride modifications of GPs were performed. Hexagonal boron nitride is a planar structure akin to graphene and has demonstrated useful chemical and electrical properties when embedded in graphitic layers. Photoemission induced by simulated solar excitation was employed to characterize the emitter electron energy distributions, and changes in the electron emission characteristics with respect to temperature identified annealing temperature limits. After several heating cycles, a single stable emission peak with work function of 2.8 eV was present for the intercalated GP sample up to 1,000 K. Up to 600 K, the potassium-intercalated boron nitride modified sample exhibited improved retention of potassium in the form of multiple emission peaks (1.8, 2.5, and 3.3 eV resulting in a large net electron emission relative to the unmodified graphitic sample. However, upon further heating to 1,000 K, the unmodified GP sample demonstrated better stability and higher emission current than the boron nitride modified sample. Both samples deintercalated above 1,000 K.

  16. Composition driven monolayer to bilayer transformation in a surfactant intercalated Mg-Al layered double hydroxide.

    Science.gov (United States)

    Naik, Vikrant V; Chalasani, Rajesh; Vasudevan, S

    2011-03-15

    The structure and organization of dodecyl sulfate (DDS) surfactant chains intercalated in an Mg-Al layered double hydroxide (LDH), Mg(1-x)Alx(OH)2, with differing Al/Mg ratios has been investigated. The Mg-Al LDHs can be prepared over a range of compositions with x varying from 0.167 to 0.37 and therefore provides a simple system to study how the organization of the alkyl chains of the intercalated DDS anions change with packing density; the Al/Mg ratio or x providing a convenient handle to do so. Powder X-ray diffraction measurements showed that at high packing densities (x ≥ 0.3) the alkyl chains of the intercalated dodecyl sulfate ions are anchored on opposing LDH sheets and arranged as bilayers with an interlayer spacing of ∼27 Å. At lower packing densities (x flat in the galleries with an interlayer spacing of ∼8 Å. For the in between compositions, 0.2 ≤ x organization of the chains and the interlayer spacing. The simulations are able to reproduce the composition driven monolayer to bilayer transformation in the arrangement of the intercalated surfactant chains and in addition provide insights into the factors that decide the arrangement of the surfactant chains in the two situations. In the bilayer arrangement, it is the dispersive van der Waals interactions between chains in opposing layers of the anchored bilayer that is responsible for the cohesive energy of the solid whereas at lower packing densities, where a monolayer arrangement is favored, Coulomb interactions between the positively charged Mg-Al LDH sheets and the negatively charged headgroup of the DDS anion dominate.

  17. Photoemission study of Ca-intercalated graphite superconductor CaC6

    International Nuclear Information System (INIS)

    Okazaki, Hiroyuki; Yoshida, Rikiya; Iwai, Keisuke; Noami, Kengo; Muro, Takayuki; Nakamura, Tetsuya; Wakita, Takanori; Muraoka, Yuji; Hirai, Masaaki; Tomioka, Fumiaki; Takano, Yoshihiko; Takenaka, Asami; Toyoda, Masahiro; Oguchi, Tamio; Yokoya, Takayoshi

    2010-01-01

    In this work, we have performed resonant photoemission studies of Ca-intercalated graphite superconductor CaC 6 . Using photon energy of the Ca 2p-3d threshold, the photoemission intensity of the peak at Fermi energy (E F ) is resonantly enhanced. This result provides spectroscopic evidence for the existence of Ca 3d states at E F , and strongly supports that Ca 3d state plays a crucial role for the superconductivity of this material with relatively high T c .

  18. Nanoparticle intercalation-induced interlayer-gap-opened graphene–polyaniline nanocomposite for enhanced supercapacitive performances

    Energy Technology Data Exchange (ETDEWEB)

    Im, Sungjin; Park, Young Ran [Graphene Research Institute & Department of Chemistry, Sejong University, Seoul 05006 (Korea, Republic of); Park, Sanghyuk [Graphene Research Institute & Department of Chemistry, Sejong University, Seoul 05006 (Korea, Republic of); Department of Energy and Mineral Resources Engineering, Sejong University, Seoul 05006 (Korea, Republic of); Kim, Hyeong Jin [Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 05006 (Korea, Republic of); Doh, Ji Hoon [Graphene Research Institute & Department of Chemistry, Sejong University, Seoul 05006 (Korea, Republic of); Division of Electron Microscopy Research, Korea Basic Science Institute (KBSI), Daejeon 34133 (Korea, Republic of); Kwon, Kyungjung [Department of Energy and Mineral Resources Engineering, Sejong University, Seoul 05006 (Korea, Republic of); Hong, Won G. [Division of Electron Microscopy Research, Korea Basic Science Institute (KBSI), Daejeon 34133 (Korea, Republic of); Kim, Byungnam [Radiation Equipment Research Division, Korea Atomic Energy Research Institute, Daejeon 34057 (Korea, Republic of); Yang, Woo Seok [Electronic Material and Device Research Center, Korea Electronics Technology Institute, Seongnam, Gyeonggi-do 13509 (Korea, Republic of); Kim, TaeYoung [Department of Bionanotechnology, Gachon University, Seongnam, Gyeonggi-do 13120 (Korea, Republic of); Hong, Young Joon, E-mail: yjhong@sejong.ac.kr [Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 05006 (Korea, Republic of)

    2017-08-01

    Highlights: • High energy–power supercapacitor electrode is demonstrated using EDLC–PC hybridized rGO–PANi nanocomposite. • A method for perpetuated intercalation of nanoparticles into interlayer gap of rGO is developed. • The intercalaction (i) exfoliates rGO layers, (ii) prevents self-agglomeration, and (iii) enlarges specific surface area of rGO for high power performance. • Electric resistance is substantially reduced by forming more rGO–PANi links via grafting of PANi to well-opened rGO edges. - Abstract: This study demonstrates a method for improving supercapacitive performance of two-dimensional nanosheet-based composite electrode. As a hybridized electrostatic double layer capacitor–electrochemical pseudocapacitor (EDLC–PC) electrode, we synthesized reduced graphene oxide–polyaniline nanofibers (rGO–PANi NFs) composite electrode. For the enhanced supercapacitive performances, insulator silver chloride nanoparticles (AgCl NPs) were intercalated into the interlayer gap of rGO. The AgCl NP intercalation (i) exfoliated rGO layers and (ii) prevented rGO-self-agglomeration that makes it difficult to utilize the high surface-to-volume ratio of ideal mono- (or few-) atomic-thick rGO layers. As a result, (iii) the specific capacitance was improved in accordance with the enlarged specific surface area of rGO. Furthermore, (iv) the well-developed rGO edges, which were opened by the AgCl intercalation, enabled formation of more bonds between PANi and rGO by selective grafting of PANi to the rGO edges. Hence, the bonds of PANi–rGO, as conducting paths, substantially reduced the total electrical resistance. Enhanced specific capacitance, ion diffusion efficiency, and reduced electrical resistance indicated the bi-functional roles of AgCl NP insertion for high performance hybridized EDLC–PC electrodes.

  19. Thin-walled nanoscrolls by multi-step intercalation from tubular halloysite-10 Å and its rearrangement upon peroxide treatment

    Science.gov (United States)

    Zsirka, Balázs; Horváth, Erzsébet; Szabó, Péter; Juzsakova, Tatjána; Szilágyi, Róbert K.; Fertig, Dávid; Makó, Éva; Varga, Tamás; Kónya, Zoltán; Kukovecz, Ákos; Kristóf, János

    2017-03-01

    Surface modification of the halloysite-10 Å mineral with tubular morphology can be achieved by slightly modified procedures developed for the delamination of kaolinite minerals. The resulting delaminated halloysite nanoparticles have unexpected surface/morphological properties that display, new potentials in catalyst development. In this work, a four-step intercalation/delamination procedure is described for the preparation of thin-walled nanoscrolls from the multi-layered hydrated halloysite mineral that consists of (1) intercalation of halloysite with potassium acetate, (2) replacement intercalation with ethylene glycol, (3) replacement intercalation with hexylamine, and (4) delamination with toluene. The intercalation steps were followed by X-ray diffraction, transmission electron microscopy, N2 adsorption-desorption, thermogravimetry, and infrared spectroscopy. Delamination eliminated the crystalline order and the crystallite size along the 'c'-axis, increased the specific surface area, greatly decreased the thickness of the mineral tubes to a monolayer, and shifted the pore diameter toward the micropore region. Unexpectedly, the removal of residual organics from intercalation steps adsorbed at the nanoscroll surface with a peroxide treatment resulted in partial recovery of crystallinity and increase of crystallite size along the 'c'-crystal direction. The d(001) value showed a diffuse pattern at 7.4-7.7 Å due to the rearrangement of the thin-walled nanoscrolls toward the initial tubular morphology of the dehydrated halloysite-7 Å mineral.

  20. Dynamics of water intercalation fronts in a nano-layered synthetic silicate: A synchrotron X-ray scattering study

    International Nuclear Information System (INIS)

    Lovoll, G.; Sandnes, B.; Meheust, Y.; Maloy, K.J.; Fossum, J.O.; Silva, G.J. da; Mundim, M.S.P.; Droppa, R. Jr.; Fonseca, D.M.

    2005-01-01

    We performed synchrotron X-ray scattering studies of the dynamics of the water intercalation front in a Na-Fluorohectorite clay. Like other smectite clays, fluorohectorite particles can swell due to intercalation of successive water layers. Monitoring the intensities of Bragg peaks of the known 1- and 2-water-layer hydration states at different positions in the sample enabled spatial and temporal measurement of the proportions of the different hydration states. From experiments with controlled temperature and an imposed humidity gradient on a quasi one-dimensional powder sample, we were able to localize the intercalation front and demonstrate that the width of this front was smaller than 2 mm after penetrating 9 mm into the sample. The speed at which the intercalation front advanced through the sample during the diffusion process was shown to decrease with time. The diffraction signature of random water intercalation in the vicinity of the intercalation front also provided information on the changes in the water content of the mesopores around clay particles

  1. Oscillatory behaviors and hierarchical assembly of contractile structures in intercalating cells

    International Nuclear Information System (INIS)

    Fernandez-Gonzalez, Rodrigo; Zallen, Jennifer A

    2011-01-01

    Fluctuations in the size of the apical cell surface have been associated with apical constriction and tissue invagination. However, it is currently not known if apical oscillatory behaviors are a unique property of constricting cells or if they constitute a universal feature of the force balance between cells in multicellular tissues. Here, we set out to determine whether oscillatory cell behaviors occur in parallel with cell intercalation during the morphogenetic process of axis elongation in the Drosophila embryo. We applied multi-color, time-lapse imaging of living embryos and SIESTA, an integrated tool for automated and semi-automated cell segmentation, tracking, and analysis of image sequences. Using SIESTA, we identified cycles of contraction and expansion of the apical surface in intercalating cells and characterized them at the molecular, cellular, and tissue scales. We demonstrate that apical oscillations are anisotropic, and this anisotropy depends on the presence of intact cell–cell junctions and spatial cues provided by the anterior–posterior patterning system. Oscillatory cell behaviors during axis elongation are associated with the hierarchical assembly and disassembly of contractile actomyosin structures at the medial cortex of the cell, with actin localization preceding myosin II and with the localization of both proteins preceding changes in cell shape. We discuss models to explain how the architecture of cytoskeletal networks regulates their contractile behavior and the mechanisms that give rise to oscillatory cell behaviors in intercalating cells

  2. X-ray absorption studies of graphite intercalates and metal-ammonia solutions

    International Nuclear Information System (INIS)

    Robertson, A.S.

    1979-09-01

    X-ray absorption spectroscopy (XAS) was used to study the arsenic fluorocomplexes, including the AsF 5 and AsF 6 - intercalates of graphite, and rubidium metal-ammonia solutions. The As-F distances obtained for AsF 3 and AsF 5 gas are both in excellent agreement with electron diffraction data (within 0.004 A). A superior measurement which is significantly shorter than the accepted value of the bond distance in an undistorted AsF 6 - octahedra is reported. Both the XAES and EXAFS data presented support the hypothesis that the AsF 5 oxidizes graphite upon intercalation to produce AsF 6 - and AsF 3 intercalant species. Changes in the Rb K-edge features which are consistent with the known properties of Rb-NH 3 are correlated with conductivity and delocalization of the solvated electrons. In the XAES region, intensity and position changes of absorption transitions are explained. In the EXAFS region, the Rb-N bond distance and the relative number of nitrogen atoms in the first shell are measured. XAS has been shown to provide unique information about the nature of the metal-ammonia phase separation, phase transition, and density fluctuations

  3. One-step exfoliation and surface modification of lamellar hydroxyapatite by intercalation of glucosamine

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Honglin [Research Institute for Biomaterials and Transportation, East China Jiaotong University, Nanchang, 330013 (China); School of Materials Science and Engineering, Tianjin University, Tianjin, 300072 (China); Li, Wei; Ji, Dehui [Research Institute for Biomaterials and Transportation, East China Jiaotong University, Nanchang, 330013 (China); Zuo, Guifu [Hebei Provincial Key Laboratory of Inorganic Nonmetallic Materials, College of Materials Science and Engineering, Hebei United University, Tangshan, 063009 (China); Xiong, Guangyao, E-mail: xiongguangyao@163.com [Research Institute for Biomaterials and Transportation, East China Jiaotong University, Nanchang, 330013 (China); Zhu, Yong [School of Chemical Engineering, Tianjin University, Tianjin, 300072 (China); Li, Lili; Han, Ming [Research Institute for Biomaterials and Transportation, East China Jiaotong University, Nanchang, 330013 (China); Wu, Caoqun [School of Materials Science and Engineering, Tianjin University, Tianjin, 300072 (China); Wan, Yizao, E-mail: yzwantju@126.com [Research Institute for Biomaterials and Transportation, East China Jiaotong University, Nanchang, 330013 (China); School of Materials Science and Engineering, Tianjin University, Tianjin, 300072 (China)

    2016-04-15

    Effective exfoliation is crucial to the application of layered materials in many fields. Herein, we report a novel effective, scalable, and ecofriendly method for the exfoliation of lamellar HAp by glucosamine intercalation such that individual HAp nanoplates can be obtained. The as-exfoliated HAp nanoplates were characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), and thermogravimetric (TG) analysis. It is found that the glucosamine intercalation not only results in complete exfoliation of lamellar HAp but also introduces the glucosamine molecules onto the surface of individual HAp nanoplates, thus obtaining separated glucosamine-grafted HAp nanoplates (Glu-HAps). Results from MTT assay demonstrate that glucosamine grafting on HAp nanoplates greatly improves the cell growth and proliferation as compared to nongrafted HAp counterparts. - Highlights: • Glucosamine was used as intercalation agent to exfoliate lamellar hydroxyapatite. • Glucosamine was grafted onto the as-exfoliated nanoplate-like hydroxyapatite. • Exfoliation and surface grafting were accomplished in one step. • Glucosamine-grafted HAp showed improved biocompatibility over nongrafted one.

  4. Intercalation of a Zn(II) complex containing ciprofloxacin drug between DNA base pairs.

    Science.gov (United States)

    Shahabadi, Nahid; Asadian, Ali Ashraf; Mahdavi, Mryam

    2017-11-02

    In this study, an attempt has been made to study the interaction of a Zn(II) complex containing an antibiotic drug, ciprofloxacin, with calf thymus DNA using spectroscopic methods. It was found that Zn(II) complex could bind with DNA via intercalation mode as evidenced by: hyperchromism in UV-Vis spectrum; these spectral characteristics suggest that the Zn(II) complex interacts with DNA most likely through a mode that involves a stacking interaction between the aromatic chromophore and the base pairs of DNA. DNA binding constant (K b = 1.4 × 10 4 M -1 ) from spectrophotometric studies of the interaction of Zn(II) complex with DNA is comparable to those of some DNA intercalative polypyridyl Ru(II) complexes 1.0 -4.8 × 10 4 M -1 . CD study showed stabilization of the right-handed B form of DNA in the presence of Zn(II) complex as observed for the classical intercalator methylene blue. Thermodynamic parameters (ΔH DNA-MB, indicating that it binds to DNA in strong competition with MB for the intercalation.

  5. Intercalating graphene with clusters of Fe3O4 nanocrystals for electrochemical supercapacitors

    Science.gov (United States)

    Ke, Qingqing; Tang, Chunhua; Liu, Yanqiong; Liu, Huajun; Wang, John

    2014-04-01

    A hierarchical nanostructure consisting of graphene sheets intercalated by clusters of Fe3O4 nanocystals is developed for high-performance supercapacitor electrode. Here we show that the negatively charged graphene oxide (GO) and positively charged Fe3O4 clusters enable a strong electrostatic interaction, generating a hierarchical 3D nanostructure, which gives rise to the intercalated composites through a rational hydrothermal process. The electrocapacitive behavior of the resultant composites is systematically investigated by cyclic voltammeter and galvanostatic charge-discharge techniques, where a positive synergistic effect between graphene and Fe3O4 clusters is identified. A maximum specific capacitance of 169 F g-1 is achieved in the Fe3O4 clusters decorated with effectively reduced graphene oxide (Fe3O4-rGO-12h), which is much higher than those of rGO (101 F g-1) and Fe3O4 (68 F g-1) at the current density of 1 Ag-1. Moreover, this intercalated hierarchical nanostructure demonstrates a good capacitance retention, retaining over 88% of the initial capacity after 1000 cycles.

  6. Perturbation of the Electron Transport Mechanism by Proton Intercalation in Nanoporous TiO2 Films

    Energy Technology Data Exchange (ETDEWEB)

    Halverson, A. F.; Zhu, K.; Erslev, P. T.; Kim, J. Y.; Neale, N. R.; Frank, A. J.

    2012-04-11

    This study addresses a long-standing controversy about the electron-transport mechanism in porous metal oxide semiconductor films that are commonly used in dye-sensitized solar cells and related systems. We investigated, by temperature-dependent time-of-flight measurements, the influence of proton intercalation on the electron-transport properties of nanoporous TiO{sub 2} films exposed to an ethanol electrolyte containing different percentages of water (0-10%). These measurements revealed that increasing the water content in the electrolyte led to increased proton intercalation into the TiO{sub 2} films, slower transport, and a dramatic change in the dependence of the thermal activation energy (E{sub a}) of the electron diffusion coefficient on the photogenerated electron density in the films. Random walk simulations based on a microscopic model incorporating exponential conduction band tail (CBT) trap states combined with a proton-induced shallow trap level with a long residence time accounted for the observed effects of proton intercalation on E{sub a}. Application of this model to the experimental results explains the conditions under which E{sub a} dependence on the photoelectron density is consistent with multiple trapping in exponential CBT states and under which it appears at variance with this model.

  7. A naproxen complex of dysprosium intercalates into calf thymus DNA base pairs

    International Nuclear Information System (INIS)

    Yang, Mengsi; Jin, Jianhua; Xu, Guiqing; Cui, Fengling; Luo, Hongxia

    2014-01-01

    Highlights: • Binding mode to ctDNA was studied by various methods. • Intercalation is the most possible binding mode. • Dynamic and static quenching occurred simultaneously. • Hydrophobic force played a major role. • Binding characteristic of rare earth complexes to DNA are dependent on the element. - Abstract: The binding mode and mechanism of dysprosium–naproxen complex (Dy–NAP) with calf thymus deoxyribonucleic acid (ctDNA) were studied using UV–vis and fluorescence spectra in physiological buffer (pH 7.4). The results showed that more than one type of quenching process occurred and the binding mode between Dy–NAP with ctDNA might be intercalation. In addition, ionic strength, iodide quenching and fluorescence polarization experiments corroborated the intercalation binding mode between Dy–NAP and ctDNA. The calculated thermodynamic parameters ΔG, ΔH and ΔS at different temperature demonstrated that hydrophobic interaction force played a major role in the binding process

  8. Effects of Cu intercalation on the graphene/Ni(111) surface: density-functional calculations

    International Nuclear Information System (INIS)

    Kwon, Se Gab; Kang, Myung Ho

    2012-01-01

    The Cu-intercalated graphene/Ni(111) surface has been studied by using density-functional theory calculations. We find that (1) the intercalation-induced decoupling between graphene and the Ni(111) substrate begins sharply at a Cu coverage of about 0.75 ML, (2) at the optimal Cu coverage of 1 ML, graphene recovers an almost ideal Dirac-cone band structure with no band gap, and (3) the Dirac point is located at 0.17 eV below the Fermi level, indicating a small charge transfer from the substrate. Cu thus plays essentially the same role as Au in realizing quasi-free-standing graphene by intercalation. Our charge character analysis shows that the Dirac-cone bands near the Fermi level reveal a weakening of their π character when crossing the Ni d bands, suggesting that the resulting low Dirac-cone intensity could possibly be the origin of the recent photoemission report of a relatively large band gap of 0.18 eV.

  9. Mechanochemical synthesis of Cu-Al and methyl orange intercalated Cu-Al layered double hydroxides

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Jun, E-mail: forsjun@whut.edu.cn [School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei 430070 (China); He, Xiaoman; Chen, Min; Hu, Huimin [School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei 430070 (China); Zhang, Qiwu, E-mail: zhangqw@whut.edu.cn [School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei 430070 (China); Liu, Xinzhong [College of Ecological Environment and Urban Construction, Fujian University of Technology, Fuzhou 350118 China (China)

    2017-04-15

    In this study, a mechanochemical route to synthesize a Cu-Al layered double hydroxide (LDH) and a methyl orange (MO) intercalated one (MO-LDH) was introduced, in which basic cupric carbonate (Cu{sub 2}(OH){sub 2}CO{sub 3}) and aluminum hydroxide (Al(OH){sub 3}) with Cu/Al molar ratio at 2/1 was first dry ground for 2 h and then agitated in water or methyl orange solution for another 4 h to obtain the LDH and MO-LDH products without any heating operation. The prepared samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Thermogravimetry (TG), Differential scanning calorimetry (DSC) and Scanning electron microscopy (SEM). The products showed high crystallinity phase of Cu-Al and MO intercalated Cu-Al LDH with no evident impurities, proving that the craft introduced here was facile and effective. The new idea can be applied in other fields to produce organic-inorganic composites. - Highlights: • A facile mechanochemical route to synthesize Cu-Al and MO intercalated Cu-Al LDH. • The products possesses high crystalline of LDH phase with no impure phases. • The dry milling process induces the element substitution between the raw materials. • The agitation operation helps the grain growth of LDH.

  10. Mechanochemical synthesis of Cu-Al and methyl orange intercalated Cu-Al layered double hydroxides

    International Nuclear Information System (INIS)

    Qu, Jun; He, Xiaoman; Chen, Min; Hu, Huimin; Zhang, Qiwu; Liu, Xinzhong

    2017-01-01

    In this study, a mechanochemical route to synthesize a Cu-Al layered double hydroxide (LDH) and a methyl orange (MO) intercalated one (MO-LDH) was introduced, in which basic cupric carbonate (Cu_2(OH)_2CO_3) and aluminum hydroxide (Al(OH)_3) with Cu/Al molar ratio at 2/1 was first dry ground for 2 h and then agitated in water or methyl orange solution for another 4 h to obtain the LDH and MO-LDH products without any heating operation. The prepared samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Thermogravimetry (TG), Differential scanning calorimetry (DSC) and Scanning electron microscopy (SEM). The products showed high crystallinity phase of Cu-Al and MO intercalated Cu-Al LDH with no evident impurities, proving that the craft introduced here was facile and effective. The new idea can be applied in other fields to produce organic-inorganic composites. - Highlights: • A facile mechanochemical route to synthesize Cu-Al and MO intercalated Cu-Al LDH. • The products possesses high crystalline of LDH phase with no impure phases. • The dry milling process induces the element substitution between the raw materials. • The agitation operation helps the grain growth of LDH.

  11. Na-Ion Intercalation and Charge Storage Mechanism in 2D Vanadium Carbide

    Energy Technology Data Exchange (ETDEWEB)

    Bak, Seong-Min [Chemistry Division, Brookhaven National Laboratory, Upton NY 11973 USA; Qiao, Ruimin [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley CA 94720 USA; Yang, Wanli [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley CA 94720 USA; Lee, Sungsik [X-Ray Science Division, Argonne National Laboratory, Argonne IL 60439 USA; Yu, Xiqian [Institute of Physics, Chinese Academy of Science, Beijing 100190 China; Anasori, Babak [Department of Material Science and Engineering, A.J. Drexel Nanomaterials Institute, Drexel University, Philadelphia PA 19104 USA; Lee, Hungsui [Chemistry Division, Brookhaven National Laboratory, Upton NY 11973 USA; Gogotsi, Yury [Department of Material Science and Engineering, A.J. Drexel Nanomaterials Institute, Drexel University, Philadelphia PA 19104 USA; Yang, Xiao-Qing [Chemistry Division, Brookhaven National Laboratory, Upton NY 11973 USA

    2017-07-14

    Two-dimensional vanadium carbide MXene containing surface functional groups (denoted as V2CTx, where Tx are surface functional groups) was synthesized and studied as anode material for Na-ion batteries. V2CTx anode exhibits reversible charge storage with good cycling stability and high rate capability through electrochemical test. The charge storage mechanism of V2CTx material during Na+ intercalation/deintercalation and the redox reaction of vanadium were studied using a combination of synchrotron based X-ray diffraction (XRD), hard X-ray absorption near edge spectroscopy (XANES) and soft X-ray absorption spectroscopy (sXAS). Experimental evidence of a major contribution of redox reaction of vanadium to the charge storage and the reversible capacity of V2CTx during sodiation/desodiation process have been provided through V K-edge XANES and V L2,3-edge sXAS results. A correlation between the CO32- content and Na+ intercalation/deintercalation states in the V2CTx electrode observed from C and O K-edge in sXAS results imply that some additional charge storage reactions may take place between the Na+-intercalated V2CTx and the carbonate based non-aqueous electrolyte. The results of this study will provide valuable information for the further studies on V2CTx as anode material for Na-ion batteries and capacitors.

  12. Effects of Intercalation on the Hole Mobility of Amorphous Semiconducting Polymer Blends

    KAUST Repository

    Cates, Nichole C.

    2010-06-08

    Fullerenes have been shown to intercalate between the side chains of many crystalline and semicrystalline polymers and to affect the properties of polymer:fullerene bulk heterojunction solar cells. Here we present the first in-depth study of intercalation in an amorphous polymer. We study blends of the widely studied amorphous polymer poly(2-methoxy-5-(3studied amorphous polymer poly(,7·studied amorphous polymer poly(-dimethyloctyloxy)-p-phenylene vinylene) (MDMO-PPV) with a variety of molecules using photoluminescence measurements, scanning electron microscopy, and space-charge limited current mobility measurements. The blends with elevated hole mobilities exhibit complete photoluminescence quenching and show no phase separation in a scanning electron microscope. We conclude that intercalation occurs in MDMO-PPV:fullerene blends and is responsible for the increase in the MDMO-PPV hole mobility by several orders of magnitude when it is blended with fullerenes, despite the dilution of the hole-conducting polymer with an electron acceptor. © 2010 American Chemical Society.

  13. Regenerable Cu-intercalated MnO2 layered cathode for highly cyclable energy dense batteries

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, Gautam G.; Gallaway, Joshua W.; Turney, Damon E.; Nyce, Michael; Huang, Jinchao; Wei, Xia; Banerjee, Sanjoy

    2017-03-06

    Manganese dioxide cathodes are inexpensive and have high theoretical capacity (based on two electrons) of 617 mAh g-1, making them attractive for low-cost, energy-dense batteries. They are used in non-rechargeable batteries with anodes like zinc. Only ~10% of the theoretical capacity is currently accessible in rechargeable alkaline systems. Attempts to access the full capacity using additives have been unsuccessful. We report a class of Bi-birnessite (a layered manganese oxide polymorph mixed with bismuth oxide (Bi2O3)) cathodes intercalated with Cu2+ that deliver near-full two-electron capacity reversibly for >6,000 cycles. The key to rechargeability lies in exploiting the redox potentials of Cu to reversibly intercalate into the Bi-birnessite-layered structure during its dissolution and precipitation process for stabilizing and enhancing its charge transfer characteristics. This process holds promise for other applications like catalysis and intercalation of metal ions into layered structures. A large prismatic rechargeable Zn-birnessite cell delivering ~140 Wh l-1 is shown.

  14. Preparation and enhanced properties of polyaniline/grafted intercalated ZnAl-LDH nanocomposites

    Science.gov (United States)

    Hu, Jinlong; Gan, Mengyu; Ma, Li; Zhang, Jun; Xie, Shuang; Xu, Fenfang; Shen, JiYue Zheng Xiaoyu; Yin, Hui

    2015-02-01

    The polymeric nanocomposites (PANI/AD-LDH) were prepared by in situ polymerization based on polyaniline (PANI) and decavanadate-intercalated and γ-aminopropyltriethoxysilane (APTS)-grafted ZnAl-layered double hydroxide (AD-LDH). FTIR and XRD studies confirm the grafting of APTS with decavanadate-intercalated LDH (D-LDH). The extent of grafting (wt%) has also been estimated on the basis of the residue left in nitrogen atmosphere at 800 °C in TGA. SEM and XPS studies show the partial exfoliation of grafted LDH in the PANI matrix and the interfacial interaction between PANI and grafted LDH, respectively. The grafted intercalated layered double hydroxide in reinforcing the properties of the PANI nanocomposites has also been investigated by open circuit potential (OCP), tafel polarization curves (TAF), electrochemical impendence spectroscopy (EIS), salt spray test and TGA-DTA. The experimental results indicate that the PANI/AD-LDH has a higher thermal stability and anticorrosion properties relative to the PANI.

  15. Intercalated Water and Organic Molecules for Electrode Materials of Rechargeable Batteries.

    Science.gov (United States)

    Lee, Hyeon Jeong; Shin, Jaeho; Choi, Jang Wook

    2018-03-24

    The intrinsic limitations of lithium-ion batteries (LIBs) with regard to safety, cost, and the availability of raw materials have promoted research on so-called "post-LIBs". The recent intense research of post-LIBs provides an invaluable lesson that existing electrode materials used in LIBs may not perform as well in post-LIBs, calling for new material designs compliant with emerging batteries based on new chemistries. One promising approach in this direction is the development of materials with intercalated water or organic molecules, as these materials demonstrate superior electrochemical performance in emerging battery systems. The enlarged ionic channel dimensions and effective shielding of the electrostatic interaction between carrier ions and the lattice host are the origins of the observed electrochemical performance. Moreover, these intercalants serve as interlayer pillars to sustain the framework for prolonged cycles. Representative examples of such intercalated materials applied to batteries based on Li + , Na + , Mg 2+ , and Zn 2+ ions and supercapacitors are considered, along with their impact in materials research. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Geometric stability, electronic structure, and intercalation mechanism of Co adatom anchors on graphene sheets

    International Nuclear Information System (INIS)

    Tang, Yanan; Chen, Weiguang; Li, Chenggang; Dai, Xianqi; Li, Wei

    2015-01-01

    We perform a systematic study of the adsorption of Co adatom on monolayer and bilayer graphene sheets, and the calculated results are compared through the van der Waals density functional (vdW-DF) and the generalized gradient approximation of Perdew, Burke and Ernzernhof (GGA + PBE) methods. For the single Co adatom, its adsorption energy at vacancy site was found to be larger than at the high-symmetry adsorption sites. For the different vdW corrections, the calculated adsorption energies of Co adatom on graphene substrates are slightly changed to some extent, but they do not affect the most preferable adsorption configurations. NEB calculations prove that the Co adatom has smaller energy barrier within pristine bilayer graphene (PBG) than that on the upper layer, indicating the high mobility of Co atom anchors at overlayer and easily aggregates. For the PBG substrate, the Co adatom intercalates into graphene sheets with a large energy barrier (9.29 eV). On the bilayer graphene with a single-vacancy (SV), the Co adatom can easily be trapped at the SV site and intercalates into graphene sheets with a much lower energy barrier (2.88 eV). These results provide valuable information on the intercalation reaction and the formation mechanism of metal impurity in graphene sheets. (paper)

  17. Thermally Induced Lateral Motion of α-Zirconium Phosphate Layers Intercalated with Hexadecylamines

    Science.gov (United States)

    Char, Kookheon

    2005-03-01

    Well-defined intercalated structure, either interdigitated layers or bilayers, of hexadecylamines (HDAs) in a confined space of a highly-functionalized layered material, α- zirconium phosphate (α-ZrP), was prepared and these two distinct intercalated structures can serve as model systems to investigate the interaction of the two monolayers whose amphiphilic tails are adjacent to each other. Acidic functional groups (-POH) on the α-ZrP are in well-ordered array and the number of functional group is quite high (i.e., cationic exchange capacity (CEC) = 664 mmole/100 g, area per one charge site = 0.24 nm^2) enough to realize the bilayers (i.e., discrete two monolayers) of HDAs within the α-ZrP interlayer. We employed the two-step intercalation mechanism for the preparation of well- ordered interdigitated layers as well as the bilayers of alkyl chains attached to both sides of the α-ZrP intergallery. An intriguing lateral motion of the α-ZrP sheets was observed with in-situ SAXS measurements for the interdigitated layer during heating and cooling cycle and verified with TEM. This lateral motion is believed to be due to the transition from the tilted to the untilted conformation of the interdigitated HDA chains and this transition is found to be thermally reversible.

  18. Interlayer Structures and Dynamics of Arsenate and Arsenite Intercalated Layered Double Hydroxides: A First Principles Study

    Directory of Open Access Journals (Sweden)

    Yingchun Zhang

    2017-03-01

    Full Text Available In this study, by using first principles simulation techniques, we explored the basal spacings, interlayer structures, and dynamics of arsenite and arsenate intercalated Layered double hydroxides (LDHs. Our results confirm that the basal spacings of NO3−-LDHs increase with layer charge densities. It is found that Arsenic (As species can enter the gallery spaces of LDHs with a Mg/Al ratio of 2:1 but they cannot enter those with lower charge densities. Interlayer species show layering distributions. All anions form a single layer distribution while water molecules form a single layer distribution at low layer charge density and a double layer distribution at high layer charge densities. H2AsO4− has two orientations in the interlayer regions (i.e., one with its three folds axis normal to the layer sheets and another with its two folds axis normal to the layer sheets, and only the latter is observed for HAsO42−. H2AsO3− orientates in a tilt-lying way. The mobility of water and NO3− increases with the layer charge densities while As species have very low mobility. Our simulations provide microscopic information of As intercalated LDHs, which can be used for further understanding of the structures of oxy-anion intercalated LDHs.

  19. Synthesis of 5-hydroxyectoine from ectoine: crystal structure of the non-heme iron(II and 2-oxoglutarate-dependent dioxygenase EctD.

    Directory of Open Access Journals (Sweden)

    Klaus Reuter

    2010-05-01

    Full Text Available As a response to high osmolality, many microorganisms synthesize various types of compatible solutes. These organic osmolytes aid in offsetting the detrimental effects of low water activity on cell physiology. One of these compatible solutes is ectoine. A sub-group of the ectoine producer's enzymatically convert this tetrahydropyrimidine into a hydroxylated derivative, 5-hydroxyectoine. This compound also functions as an effective osmostress protectant and compatible solute but it possesses properties that differ in several aspects from those of ectoine. The enzyme responsible for ectoine hydroxylation (EctD is a member of the non-heme iron(II-containing and 2-oxoglutarate-dependent dioxygenases (EC 1.14.11. These enzymes couple the decarboxylation of 2-oxoglutarate with the formation of a high-energy ferryl-oxo intermediate to catalyze the oxidation of the bound organic substrate. We report here the crystal structure of the ectoine hydroxylase EctD from the moderate halophile Virgibacillus salexigens in complex with Fe(3+ at a resolution of 1.85 A. Like other non-heme iron(II and 2-oxoglutarate dependent dioxygenases, the core of the EctD structure consists of a double-stranded beta-helix forming the main portion of the active-site of the enzyme. The positioning of the iron ligand in the active-site of EctD is mediated by an evolutionarily conserved 2-His-1-carboxylate iron-binding motif. The side chains of the three residues forming this iron-binding site protrude into a deep cavity in the EctD structure that also harbours the 2-oxoglutarate co-substrate-binding site. Database searches revealed a widespread occurrence of EctD-type proteins in members of the Bacteria but only in a single representative of the Archaea, the marine crenarchaeon Nitrosopumilus maritimus. The EctD crystal structure reported here can serve as a template to guide further biochemical and structural studies of this biotechnologically interesting enzyme family.

  20. Thin-walled nanoscrolls by multi-step intercalation from tubular halloysite-10 Å and its rearrangement upon peroxide treatment

    International Nuclear Information System (INIS)

    Zsirka, Balázs; Horváth, Erzsébet; Szabó, Péter; Juzsakova, Tatjána; Szilágyi, Róbert K.; Fertig, Dávid; Makó, Éva; Varga, Tamás

    2017-01-01

    Highlights: • Halloysite intercalation/delamination. • Thin-walled nanoscroll preparation. • Oxidative surface cleaning with H_2O_2 and heating. • X-ray diffraction, TEM, N_2 adsorption, TG/DTG and FT-IR/ATR measurements. • Nanoscroll rearrangement, periodicity along the crystallographic ‘c’-axis. - Abstract: Surface modification of the halloysite-10 Å mineral with tubular morphology can be achieved by slightly modified procedures developed for the delamination of kaolinite minerals. The resulting delaminated halloysite nanoparticles have unexpected surface/morphological properties that display, new potentials in catalyst development. In this work, a four-step intercalation/delamination procedure is described for the preparation of thin-walled nanoscrolls from the multi-layered hydrated halloysite mineral that consists of (1) intercalation of halloysite with potassium acetate, (2) replacement intercalation with ethylene glycol, (3) replacement intercalation with hexylamine, and (4) delamination with toluene. The intercalation steps were followed by X-ray diffraction, transmission electron microscopy, N_2 adsorption-desorption, thermogravimetry, and infrared spectroscopy. Delamination eliminated the crystalline order and the crystallite size along the ‘c’-axis, increased the specific surface area, greatly decreased the thickness of the mineral tubes to a monolayer, and shifted the pore diameter toward the micropore region. Unexpectedly, the removal of residual organics from intercalation steps adsorbed at the nanoscroll surface with a peroxide treatment resulted in partial recovery of crystallinity and increase of crystallite size along the ‘c’-crystal direction. The d(001) value showed a diffuse pattern at 7.4–7.7 Å due to the rearrangement of the thin-walled nanoscrolls toward the initial tubular morphology of the dehydrated halloysite-7 Å mineral.

  1. Thin-walled nanoscrolls by multi-step intercalation from tubular halloysite-10 Å and its rearrangement upon peroxide treatment

    Energy Technology Data Exchange (ETDEWEB)

    Zsirka, Balázs, E-mail: zsirkab@almos.vein.hu [University of Pannonia, Institute of Environmental Engineering, P.O. Box 158, Veszprém 8201 Hungary (Hungary); Horváth, Erzsébet, E-mail: erzsebet.horvath@gmail.com [University of Pannonia, Institute of Environmental Engineering, P.O. Box 158, Veszprém 8201 Hungary (Hungary); Szabó, Péter, E-mail: xysma@msn.com [University of Pannonia, Department of Analytical Chemistry, P.O. Box 158, Veszprém 8201 Hungary (Hungary); Juzsakova, Tatjána, E-mail: yuzhakova@almos.uni-pannon.hu [University of Pannonia, Institute of Environmental Engineering, P.O. Box 158, Veszprém 8201 Hungary (Hungary); Szilágyi, Róbert K., E-mail: szilagyi@montana.edu [Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717 (United States); Fertig, Dávid, E-mail: fertig.david92@gmail.com [University of Pannonia, Department of Analytical Chemistry, P.O. Box 158, Veszprém 8201 Hungary (Hungary); Makó, Éva, E-mail: makoe@almos.vein.hu [University of Pannonia, Institute of Materials Engineering, P.O. Box 158, Veszprém 8201 Hungary (Hungary); Varga, Tamás, E-mail: vtamas@chem.u-szeged.hu [University of Szeged, Department of Applied and Environmental Chemistry, Rerrich B. tér 1., Szeged H-6720 Hungary (Hungary); and others

    2017-03-31

    Highlights: • Halloysite intercalation/delamination. • Thin-walled nanoscroll preparation. • Oxidative surface cleaning with H{sub 2}O{sub 2} and heating. • X-ray diffraction, TEM, N{sub 2} adsorption, TG/DTG and FT-IR/ATR measurements. • Nanoscroll rearrangement, periodicity along the crystallographic ‘c’-axis. - Abstract: Surface modification of the halloysite-10 Å mineral with tubular morphology can be achieved by slightly modified procedures developed for the delamination of kaolinite minerals. The resulting delaminated halloysite nanoparticles have unexpected surface/morphological properties that display, new potentials in catalyst development. In this work, a four-step intercalation/delamination procedure is described for the preparation of thin-walled nanoscrolls from the multi-layered hydrated halloysite mineral that consists of (1) intercalation of halloysite with potassium acetate, (2) replacement intercalation with ethylene glycol, (3) replacement intercalation with hexylamine, and (4) delamination with toluene. The intercalation steps were followed by X-ray diffraction, transmission electron microscopy, N{sub 2} adsorption-desorption, thermogravimetry, and infrared spectroscopy. Delamination eliminated the crystalline order and the crystallite size along the ‘c’-axis, increased the specific surface area, greatly decreased the thickness of the mineral tubes to a monolayer, and shifted the pore diameter toward the micropore region. Unexpectedly, the removal of residual organics from intercalation steps adsorbed at the nanoscroll surface with a peroxide treatment resulted in partial recovery of crystallinity and increase of crystallite size along the ‘c’-crystal direction. The d(001) value showed a diffuse pattern at 7.4–7.7 Å due to the rearrangement of the thin-walled nanoscrolls toward the initial tubular morphology of the dehydrated halloysite-7 Å mineral.

  2. Manganese-incorporated iron(III) oxide-graphene magnetic nanocomposite: synthesis, characterization, and application for the arsenic(III)-sorption from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Nandi, Debabrata; Gupta, Kaushik; Ghosh, Arup Kumar [Presidency University, Department of Chemistry and Biochemistry (India); De, Amitabha [Saha Institute of Nuclear Physics, Chemical Science Division (India); Banerjee, Sangam [Saha Institute of Nuclear Physics, Surface Physics Division (India); Ghosh, Uday Chand, E-mail: ucghosh@yahoo.co.in [Presidency University, Department of Chemistry and Biochemistry (India)

    2012-12-15

    High specific surface area of graphene (GR) has gained special scientific attention in developing magnetic GR nanocomposite aiming to apply for the remediation of diverse environmental problems like point-of-use water purification and simultaneous separation of contaminants applying low external magnetic field (<1.0 T) from ground water. Fabrication of magnetic manganese-incorporated iron(III) oxide (Mn{sub x}{sup 2+}Fe{sub 2-x}{sup 3+}O{sub 4}{sup 2-}) (IMBO)-GR nanocomposite is reported by exfoliating the GR layers. Latest microscopic, spectroscopic, powder X-ray diffraction, BET surface area, and superconducting quantum interference device characterizations showed that the material is a magnetic nanocomposite with high specific surface area (280 m{sup 2} g{sup -1}) and pore volume (0.3362 cm{sup 3} g{sup -1}). Use of this composite for the immobilization of carcinogenic As(III) from water at 300 K and pH {approx}7.0 showed that the nanocomposite has higher binding efficiency with As(III) than the IMBO owing to its high specific surface area. The composite showed almost complete (>99.9 %) As(III) removal ({<=}10 {mu}g L{sup -1}) from water. External magnetic field of 0.3 T efficiently separated the water dispersed composite (0.01 g/10 mL) at room temperature (300 K). Thus, this composite is a promising material which can be used effectively as a potent As(III) immobilizer from the contaminated groundwater (>10 {mu}g L{sup -1}) to improve drinking water quality.

  3. Theoretical analysis of the binding of iron(III) protoporphyrin IX to 4-methoxyacetophenone thiosemicarbazone via DFT-D3, MEP, QTAIM, NCI, ELF, and LOL studies.

    Science.gov (United States)

    Nkungli, Nyiang Kennet; Ghogomu, Julius Numbonui

    2017-07-01

    Thiosemicarbazones display diverse pharmacological properties, including antimalarial activities. Their pharmacological activities have been studied in depth, but little of this research has focused on their antimalarial mode of action. To elucidate this antimalarial mechanism, we investigated the nature of the interactions between iron(III) protoporphyrin IX (Fe(III)PPIX) and the thione-thiol tautomers of 4-methoxyacetophenone thiosemicarbazone (MAPTSC). Dispersion-corrected density functional theory (DFT-D3), the quantum theory of atoms in molecules (QTAIM), the noncovalent interaction (NCI) index, the electron localization function (ELF), the localized orbital locator (LOL), and thermodynamic calculations were employed in this work. Fe(III)PPIX-MAPTSC binding is expected to inhibit hemozoin formation, thereby preventing Fe(III)PPIX detoxification in plasmodia. Preliminary studies geared toward the identification of atomic binding sites in the thione-thiol tautomers of MAPTSC were carried out using molecular electrostatic potential (MEP) maps and conceptual DFT-based local reactivity indices. The thionic sulfur and the 2 N-azomethine nitrogen/thiol sulfur of, respectively, the thione and thiol tautomers of MAPTSC were identified as the most favorable nucleophilic sites for electrophilic attack. The negative values of the computed Fe(III)PPIX-MAPTSC binding energies, enthalpies, and Gibbs free energies are indicative of the existence and stability of Fe(III)PPIX-MAPTSC complexes. MAPTSC-Fe(III) coordinate bonds and strong hydrogen bonds (N-H···O) between the NH 2 group in MAPTSC and the C=O group in one propionate side chain of Fe(III)PPIX are crucial to Fe(III)PPIX-MAPTSC binding. QTAIM, NCI, ELF, and LOL analyses revealed a subtle interplay of weak noncovalent interactions dominated by dispersive-like van der Waals interactions between Fe(III)PPIX and MAPTSC that stabilize the Fe(III)PPIX-MAPTSC complexes.

  4. Heteroleptic and Homoleptic Iron(III Spin-Crossover Complexes; Effects of Ligand Substituents and Intermolecular Interactions between Co-Cation/Anion and the Complex

    Directory of Open Access Journals (Sweden)

    Wasinee Phonsri

    2017-08-01

    Full Text Available The structural and magnetic properties of a range of new iron(III bis-tridentate Schiff base complexes are described with emphasis on how intermolecular structural interactions influence spin states and spin crossover (SCO in these d5 materials. Three pairs of complexes were investigated. The first pair are the neutral, heteroleptic complexes [Fe(3-OMe-SalEen(thsa] 1 and [Fe(3-MeOSalEen(3-EtOthsa] 2, where 3-R-HSalEen = (E-2-(((2-(ethylaminoethyliminomethyl-6-R-phenol and 3-R-H2thsa = thiosemicarbazone-3-R-salicylaldimine. They display spin transitions above room temperature. However, 2 shows incomplete and gradual change, while SCO in 1 is complete and more abrupt. Lower cooperativity in 2 is ascribed to the lack of π–π interactions, compared to 1. The second pair, cationic species [Fe(3-EtOSalEen2]NO3 3 and [Fe(3-EtOSalEen2]Cl 4 differ only in the counter-anion. They show partial SCO above room temperature with 3 displaying a sharp transition at 343 K. Weak hydrogen bonds from cation to Cl− probably lead to weaker cooperativity in 4. The last pair, CsH2O[Fe(3-MeO-thsa2] 5 and Cs(H2O2[Fe(5-NO2-thsa2] 6, are anionic homoleptic chelates that have different substituents on the salicylaldiminate rings of thsa2−. The Cs cations bond to O atoms of water and the ligands, in unusual ways thus forming attractive 1D and 3D networks in 5 and 6, respectively, and 5 remains HS (high spin at all temperatures while 6 remains LS (low spin. Comparisons are made to other literature examples of Cs salts of [Fe(5-R-thsa2]− (R = H and Br.

  5. High-resolution 13C nuclear magnetic resonance evidence of phase transition of Rb,Cs-intercalated single-walled nanotubes

    KAUST Repository

    Bouhrara, M.

    2011-09-06

    We present 13 C high-resolution magic-angle-turning (MAT) and magic angle spinning nuclear magnetic resonance data of Cs and Rb intercalated single walled carbon nanotubes. We find two distinct phases at different intercalation levels. A simple charge transfer is applicable at low intercalation level. The new phase at high intercalation level is accompanied by a hybridization of alkali (s) orbitals with the carbon (sp2) orbitals of the single walled nanotubes, which indicate bundle surface sites is the most probable alkali site.

  6. Lithium ion intercalation in thin crystals of hexagonal TaSe2 gated by a polymer electrolyte

    Science.gov (United States)

    Wu, Yueshen; Lian, Hailong; He, Jiaming; Liu, Jinyu; Wang, Shun; Xing, Hui; Mao, Zhiqiang; Liu, Ying

    2018-01-01

    Ionic liquid gating has been used to modify the properties of layered transition metal dichalcogenides (TMDCs), including two-dimensional (2D) crystals of TMDCs used extensively recently in the device work, which has led to observations of properties not seen in the bulk. The main effect comes from the electrostatic gating due to the strong electric field at the interface. In addition, ionic liquid gating also leads to ion intercalation when the ion size of the gate electrolyte is small compared to the interlayer spacing of TMDCs. However, the microscopic processes of ion intercalation have rarely been explored in layered TMDCs. Here, we employed a technique combining photolithography device fabrication and electrical transport measurements on the thin crystals of hexagonal TaSe2 using multiple channel devices gated by a polymer electrolyte LiClO4/Polyethylene oxide (PEO). The gate voltage and time dependent source-drain resistances of these thin crystals were used to obtain information on the intercalation process, the effect of ion intercalation, and the correlation between the ion occupation of allowed interstitial sites and the device characteristics. We found a gate voltage controlled modulation of the charge density waves and a scattering rate of charge carriers. Our work suggests that ion intercalation can be a useful tool for layered materials engineering and 2D crystal device design.

  7. Rare earth and zinc layered hydroxide salts intercalated with the 2-aminobenzoate anion as organic luminescent sensitizer

    Energy Technology Data Exchange (ETDEWEB)

    Cursino, Ana Cristina Trindade, E-mail: anacursino@ufpr.br [CEPESQ – Research Centre of Applied Chemistry, Department of Chemistry, Universidade Federal do Paraná – P.O. Box 19081, 81531-980 Curitiba, PR (Brazil); Rives, Vicente, E-mail: vrives@usal.es [GIR-QUESCAT – Department of Inorganic Chemistry, Universidad de Salamanca, Plaza de la Merced S/N, 37998 Salamanca (Spain); Arizaga, Gregorio Guadalupe Carbajal, E-mail: gregoriocarbajal@yahoo.com.mx [Universidad de Guadalajara, Department of Chemistry, Boulevard Marcelino García Barragán 1421, C.P. 44430 Guadalajara, Jalisco (Mexico); Trujillano, Raquel, E-mail: rakel@usal.es [GIR-QUESCAT – Department of Inorganic Chemistry, Universidad de Salamanca, Plaza de la Merced S/N, 37998 Salamanca (Spain); Wypych, Fernando, E-mail: wypych@ufpr.br [CEPESQ – Research Centre of Applied Chemistry, Department of Chemistry, Universidade Federal do Paraná – P.O. Box 19081, 81531-980 Curitiba, PR (Brazil)

    2015-10-15

    Rare earth (RE = Eu, Y and Tb) and zinc layered hydroxide salts intercalated with nitrate anions were synthesized, followed by exchange with 2-aminobenzoate. The UV absorption ability was improved after intercalation/grafting in relation to that shown by the parent material. - Highlights: • Rare earth (RE = Eu, Y and Tb) and zinc layered hydroxide were synthesized. • Intercalated nitrate anions were exchanged by 2-aminobenzoate. • In all the 2-aminobenzoate containing compounds, the grafting reaction was detected. • The UV absorption ability was improved after the exchange reactions. • Rare earth hydroxide salts are potential matrixes to produce luminescent materials. - Abstract: Rare earth (RE = Eu, Y and Tb) and zinc layered hydroxide salts intercalated with nitrate anions were synthesized, followed by exchange with 2-aminobenzoate. The obtained compounds were characterized by powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) and ultraviolet visible (UV–vis) spectroscopies, fluorescence measurements and thermal analysis (TGA/DTA). The results from FTIR spectroscopy suggest a direct coordination of 2-aminobenzoate to the metal cations of the inorganic layered structure. The organic derivative products from the intercalation reactions absorb a broader range of UV-light in relation to that shown by the parent material; the photoluminescence measurements present a strong violet, blue and green luminescence under UV-light excitation for layered compounds with, Zn, Y and Tb, respectively. Rare earth hydroxide salts (RE-LHS) are potential alternative matrices for the immobilization of organic species to produce luminescent materials.

  8. Release behavior and toxicity profiles towards A549 cell lines of ciprofloxacin from its layered zinc hydroxide intercalation compound.

    Science.gov (United States)

    Abdul Latip, Ahmad Faiz; Hussein, Mohd Zobir; Stanslas, Johnson; Wong, Charng Choon; Adnan, Rohana

    2013-01-01

    Layered hydroxides salts (LHS), a layered inorganic compound is gaining attention in a wide range of applications, particularly due to its unique anion exchange properties. In this work, layered zinc hydroxide nitrate (LZH), a family member of LHS was intercalated with anionic ciprofloxacin (CFX), a broad spectrum antibiotic via ion exchange in a mixture solution of water:ethanol. Powder x-ray diffraction (XRD), Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA) confirmed the drug anions were successfully intercalated in the interlayer space of LZH. Specific surface area of the obtained compound was increased compared to that of the host due to the different pore textures between the two materials. CFX anions were slowly released over 80 hours in phosphate-buffered saline (PBS) solution due to strong interactions that occurred between the intercalated anions and the host lattices. The intercalation compound demonstrated enhanced antiproliferative effects towards A549 cancer cells compared to the toxicity of CFX alone. Strong host-guest interactions between the LZH lattice and the CFX anion give rise to a new intercalation compound that demonstrates sustained release mode and enhanced toxicity effects towards A549 cell lines. These findings should serve as foundations towards further developments of the brucite-like host material in drug delivery systems.

  9. Rare earth and zinc layered hydroxide salts intercalated with the 2-aminobenzoate anion as organic luminescent sensitizer

    International Nuclear Information System (INIS)

    Cursino, Ana Cristina Trindade; Rives, Vicente; Arizaga, Gregorio Guadalupe Carbajal; Trujillano, Raquel; Wypych, Fernando

    2015-01-01

    Rare earth (RE = Eu, Y and Tb) and zinc layered hydroxide salts intercalated with nitrate anions were synthesized, followed by exchange with 2-aminobenzoate. The UV absorption ability was improved after intercalation/grafting in relation to that shown by the parent material. - Highlights: • Rare earth (RE = Eu, Y and Tb) and zinc layered hydroxide were synthesized. • Intercalated nitrate anions were exchanged by 2-aminobenzoate. • In all the 2-aminobenzoate containing compounds, the grafting reaction was detected. • The UV absorption ability was improved after the exchange reactions. • Rare earth hydroxide salts are potential matrixes to produce luminescent materials. - Abstract: Rare earth (RE = Eu, Y and Tb) and zinc layered hydroxide salts intercalated with nitrate anions were synthesized, followed by exchange with 2-aminobenzoate. The obtained compounds were characterized by powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) and ultraviolet visible (UV–vis) spectroscopies, fluorescence measurements and thermal analysis (TGA/DTA). The results from FTIR spectroscopy suggest a direct coordination of 2-aminobenzoate to the metal cations of the inorganic layered structure. The organic derivative products from the intercalation reactions absorb a broader range of UV-light in relation to that shown by the parent material; the photoluminescence measurements present a strong violet, blue and green luminescence under UV-light excitation for layered compounds with, Zn, Y and Tb, respectively. Rare earth hydroxide salts (RE-LHS) are potential alternative matrices for the immobilization of organic species to produce luminescent materials

  10. Hydrogen intercalation of single and multiple layer graphene synthesized on Si-terminated SiC(0001) surface

    International Nuclear Information System (INIS)

    Sołtys, Jakub; Piechota, Jacek; Ptasinska, Maria; Krukowski, Stanisław

    2014-01-01

    Ab initio density functional theory simulations were used to investigate the influence of hydrogen intercalation on the electronic properties of single and multiple graphene layers deposited on the SiC(0001) surface (Si-face). It is shown that single carbon layer, known as a buffer layer, covalently bound to the SiC substrate, is liberated after hydrogen intercalation, showing characteristic Dirac cones in the band structure. This is in agreement with the results of angle resolved photoelectron spectroscopy measurements of hydrogen intercalation of SiC-graphene samples. In contrast to that hydrogen intercalation has limited impact on the multiple sheet graphene, deposited on Si-terminated SiC surface. The covalently bound buffer layer is liberated attaining its graphene like structure and dispersion relation typical for multilayer graphene. Nevertheless, before and after intercalation, the four layer graphene preserved the following dispersion relations in the vicinity of K point: linear for (AAAA) stacking, direct parabolic for Bernal (ABAB) stacking and “wizard hat” parabolic for rhombohedral (ABCA) stacking

  11. Electrical and mechanical properties of poly(ethylene oxide)/intercalated clay polymer electrolyte

    International Nuclear Information System (INIS)

    Moreno, Mabel; Quijada, Raúl; Santa Ana, María A.; Benavente, Eglantina; Gomez-Romero, Pedro; González, Guillermo

    2011-01-01

    Highlights: ► Poly(ethylene oxide)/intercalated clay nanocomposite as filler in solid poly(ethylene oxide) electrolytes. ► Nanocomposite filler improves mechanical properties, transparency, and conductivity of poly(ethylene oxide) electrolyte films. ► Nanocomposite is more effective than unmodified clay in improving polymer electrolyte properties. ► Low Li/polymer ratio avoids crystalline Li complexes, so effects mainly arise from the polymer. ► High nanocomposite/poly(ethylene oxide)-matrix affinity enhances microhomogeneity in the polyelectrolyte. - Abstract: Solvent-free solid polymer electrolytes (SPEs) based on two different poly(ethylene oxide), PEO Mw 600,000 and 4,000,000 and intercalated clays are reported. The inorganic additives used were lithiated bentonite and the nanocomposite PEO-bentonite with the same polymer used as matrix. SPE films, obtained in the scale of grams by mixing the components in a Brabender-type batch mixer and molding at 130 °C, were characterized by X-ray diffraction analysis, UV–vis spectroscopy, and thermal analysis. During the preparation of the films, the unmodified clay got intercalated in situ. Comparative analysis of ionic conductivity and mechanical properties of the films show that the conductivity increases with the inclusion of fillers, especially for the polymer with low molecular weight. This effect is more pronounced when using PEO-bentonite as additive. Under selected work conditions, avoiding the presence of crystalline lithium complexes, observed effects are mainly centered on the polymer. An explanation, considering the higher affinity between the modified clay and PEO matrix which leads to differences in the micro homogeneity degree between both types of polymer electrolytes is proposed.

  12. Synthesis, characterization, and controlled release anticorrosion behavior of benzoate intercalated Zn-Al layered double hydroxides

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yi [Shandong Provincial Key Lab of Corrosion Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071 (China); Zhang, Dun, E-mail: zhangdun@qdio.ac.cn [Shandong Provincial Key Lab of Corrosion Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071 (China)

    2011-11-15

    Graphical abstract: The benzoate anion released from Zn-Al LDHs provides a more effective long-term protection against corrosion of Q235 carbon steel in 3.5% NaCl solution. Highlights: {yields} A benzoate anion corrosion inhibitor intercalated Zn-Al layered double hydroxides (LDHs) has been assembled by coprecipitation method. {yields} The kinetic simulation indicates that the ion-exchange one is responsible for the release process and the diffusion through particle is the rate limiting step. {yields} A significant reduction of the corrosion rate is observed when the LDH nanohybrid is present in the corrosive media. -- Abstract: Corrosion inhibitor-inorganic clay composite including benzoate anion intercalated Zn-Al layered double hydroxides (LDHs) are assembled by coprecipitation. Powder X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectrum analyses indicate that the benzoate anion is successfully intercalated into the LDH interlayer and the benzene planes are vertically bilayer-positioned as a quasi-guest ion-pair form in the gallery space. Kinetic simulation for the release data, XRD and FT-IR analyses of samples recovered from the release medium indicate that ion-exchange is responsible for the release process and diffusion through the particle is also indicated to be the rate-limiting step. The anticorrosion capabilities of LDHs loaded with corrosion inhibitor toward Q235 carbon steel are analyzed by polarization curve and electrochemical impedance spectroscopy methods. Significant reduction of corrosion rate is observed when the LDH nanohybrid is present in the corrosive medium. This hybrid material may potentially be applied as a nanocontainer in self-healing coatings.

  13. Molecular Simulation Models of Carbon Dioxide Intercalation in Hydrated Sodium Montmorillonite

    Energy Technology Data Exchange (ETDEWEB)

    Myshakin, Evgeniy [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Saidi, Wissam [Univ. of Pittsburgh, PA (United States); Romanov, Vyacheslav [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Cygan, Randall [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jordan, Kenneth [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Univ. of Pittsburgh, PA (United States); Guthrie, George [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-11-22

    In this study, classical molecular dynamics simulations and density functional theory (DFT)-based molecular dynamics are used to elucidate the process of CO2 intercalation into hydrated Na-montmorillonite at P-T conditions relevant to geological formations suitable for CO2 storage. Of particular interest are the structural and transport properties of interlayer species after CO2 intercalation. The conducted simulations allowed the research team to quantify expansion/contraction of smectite as a function of CO2 and H2O compositions. The resulting swelling curves can be used to gauge the amount of stored CO2, compare it to the experiment, and estimate changes in geomechanical properties of the storage formation. The obtained results showed that the infrared signal of the asymmetric stretch vibration of CO2 molecule is extremely sensitive to the solvent environment. The extent of the frequency shift relative to the gas-phase value can be used to probe hydration level in the interlayer with intercalated CO2. Interaction of supercritical CO2 with brine in deep geological formations promotes an increase of hydrophobicity of clay surfaces. As a result of wettability alteration, estimated diffusion constants of CO2 and H2O increase with the increased CO2 load; this can contribute to faster migration of CO2 throughout the formation.

  14. Renal type a intercalated cells contain albumin in organelles with aldosterone-regulated abundance.

    Directory of Open Access Journals (Sweden)

    Thomas Buus Jensen

    Full Text Available Albumin has been identified in preparations of renal distal tubules and collecting ducts by mass spectrometry. This study aimed to establish whether albumin was a contaminant in those studies or actually present in the tubular cells, and if so, identify the albumin containing cells and commence exploration of the origin of the intracellular albumin. In addition to the expected proximal tubular albumin immunoreactivity, albumin was localized to mouse renal type-A intercalated cells and cells in the interstitium by three anti-albumin antibodies. Albumin did not colocalize with markers for early endosomes (EEA1, late endosomes/lysosomes (cathepsin D or recycling endosomes (Rab11. Immuno-gold electron microscopy confirmed the presence of albumin-containing large spherical membrane associated bodies in the basal parts of intercalated cells. Message for albumin was detected in mouse renal cortex as well as in a wide variety of other tissues by RT-PCR, but was absent from isolated connecting tubules and cortical collecting ducts. Wild type I MDCK cells showed robust uptake of fluorescein-albumin from the basolateral side but not from the apical side when grown on permeable support. Only a subset of cells with low peanut agglutinin binding took up albumin. Albumin-aldosterone conjugates were also internalized from the basolateral side by MDCK cells. Aldosterone administration for 24 and 48 hours decreased albumin abundance in connecting tubules and cortical collecting ducts from mouse kidneys. We suggest that albumin is produced within the renal interstitium and taken up from the basolateral side by type-A intercalated cells by clathrin and dynamin independent pathways and speculate that the protein might act as a carrier of less water-soluble substances across the renal interstitium from the capillaries to the tubular cells.

  15. Synthesis and structural characterization of coaxial nano tubes intercalated of molybdenum disulfide with carbon

    International Nuclear Information System (INIS)

    Reza San German, C.M.

    2005-01-01

    In this work the study of some fundamental aspects in the growth of unidimensional systems of coaxial nano tubes from the mold method is approached. This method is an inclusion technique of a precursor reagent into oxide nano porous alumina film (mold), and later applying some processes of synthesis it is gotten to obtain the wished material. The synthesized structures are identified later because they take place by means of the initial formation of nano tubes of MoS 2 , enclosing to carbon nano tubes by the same method, with propylene flow which generates a graphitization process that 'copy' the mold through as it flows. Binary phase MoS 2 + C nano tubes were synthesized by propylene pyrolysis inside MoS 2 nano tubes prepared by template assisted technique. The large coaxial nano tubes constituted of graphite sheets inserted between the MoS 2 layers forming the outer part, and coaxial multi wall carbon nano tubes (MWCNT) intercalated with MoS 2 inside. High resolution electron microscopy (HRTEM), electron energy loss spectroscopy (EELS), high angle annular dark field (HAADF), gatan image filter (GIF), nano beam electron diffraction patterns (NBEDP), along with molecular dynamics simulation and quantum mechanical calculations were used to characterize the samples. The one-dimensional structures exhibit diverse morphologies such as long straight and twisted nano tubes with several structural irregularities. The inter-planar spacing between MoS 2 layers was found to increase from 6.3 to 7.4 A due to intercalation with carbon. Simulated HREM images revealed the presence of these twisted nano structures, with mechanical stretch into intercalate carbon between MoS 2 layers. Our results open up the possibility of using MoS 2 nano tubes as templates for the synthesis of new one- dimensional binary phase systems. (Author)

  16. Efficient dechlorination of carbon tetrachloride by hydrophobic green rust intercalated with dodecanoate anions

    DEFF Research Database (Denmark)

    Ayala Luis, Karina Barbara; Ginette Anneliese Cooper, Nicola; Bender Koch, Christian

    2012-01-01

    similar to those found in heavily contaminated groundwater close to polluted industrial sites (14 988 mu M) was reduced mainly to the fully dechlorinated products carbon monoxide (CO, yields >54 and formic acid (HCOOH, yields >6. Minor formation of chloroform (CF), the only chlorinated degradation product......The reductive dechlorination of carbon tetrachloride (CT) by Fe-II-Fe-III hydroxide (green rust) intercalated with dodecanoate, (Fe4Fe2III)-Fe-II (OH)(12)(C12H23O2)(2)center dot gamma H2O (designated GR(C12)), at pH similar to 8 and at room temperature was investigated. CT at concentration levels...

  17. Preparation of Mg/Al-LDHs intercalated with dodecanoic acid and investigation of its antiwear ability

    International Nuclear Information System (INIS)

    Zhao, Dong; Bai, Zhimin; Zhao, Fuyan

    2012-01-01

    Graphical abstract: Comparable studies of nano Mg/Al-LDHs powder on the anti-wear properties of lubricating oil were carried out on four-ball and gear testing machine. Mg/Al-NO 3 − -LDHs and Mg/Al-DA-LDHs powder in base oil possess an excellent friction-reducing property, with a friction coefficient at 23.9% and 22.2% which are lower than that of the base oil Highlights: ► We synthesized nano Mg/Al-NO 3 − (DA)-LDHs via coprecipitation and anion exchange. ► The optimal exchanging condition is as follows: water dispersion and pH value of 5. ► The tribological properties of LDHs were studied on four-ball and gear machine. ► We reported nano LHDs as anti-wear materials in lubricates for the first time. ► The greatest decline in friction coefficient of lubricates with LDHs is up to 23.9%. -- Abstract: Layered double hydroxides (LDHs) intercalated with dodecanoic acid have been prepared by anion exchange with Mg/Al-NO 3 − -LDHs as the precursor under acid condition with water and ethanol as the dispersion medium. The obtained materials were characterized by X-ray diffraction (XRD), thermogravimetric and differential thermal analyser (TG–DTA), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and BET. Patterns of XRD and FTIR show that interlayer nitrate ions have substituted with dodecanoic acid and the gallery height has increased from 0.88 nm to 1.99 nm. The interlayer distance of the intercalated materials increases with the increase of pH value due to the different arrangement of interlayer anions. The tribological performance of LDHs precursor and intercalated LDHs in base oil were studied for the first time by using four-ball wear machine and gear testing machine. Experimental results show that the LDHs precursor and intercalated LDHs powder are excellent in friction-reducing, with decreases in friction coefficient by 23.9% and 22.2% respectively comparing with base oil.

  18. Mechanical exfoliation of epitaxial graphene on Ir(111) enabled by Br2 intercalation.

    Science.gov (United States)

    Herbig, Charlotte; Kaiser, Markus; Bendiab, Nedjma; Schumacher, Stefan; Förster, Daniel F; Coraux, Johann; Meerholz, Klaus; Michely, Thomas; Busse, Carsten

    2012-08-08

    We show here that Br(2) intercalation is an efficient method to enable exfoliation of epitaxial graphene on metals by adhesive tape. We exemplify this method for high-quality graphene of macroscopic extension on Ir(111). The sample quality and the transfer process are monitored using low-energy electron diffraction (LEED), scanning tunneling microscopy (STM), scanning electron microscopy (SEM) and Raman spectroscopy. The developed process provides an opportunity for preparing graphene of strictly monatomic thickness and well-defined orientation including the transfer to poly(ethylene terephthalate) (PET) foil.

  19. Ultrahigh intercalation pseudocapacitance of mesoporous orthorhombic niobium pentoxide from a novel cellulose nanocrystal template

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Lingping; Zhang, Chuangfang; Wang, Jitong; Long, Donghui, E-mail: longdh@mail.ecust.edu.cn; Qiao, Wenming; Ling, Licheng

    2015-01-15

    A facile biotemplating method has been developed to prepare mesoporous orthorhombic nobium pentoxide (T-Nb{sub 2}O{sub 5}) films with ultrahigh lithium ion (Li{sup +}) intercalation pseudocapacitance. Nanorod-like cellulose nanocrystals (CNs) with 5–10 nm in width and 100–300 nm in length are produced by the hydrolysis of cotton, which can serve as a novel soft templating agent enabling the straightforward synthesis of mesoporous T-Nb{sub 2}O{sub 5} films. By varying the niobic-to-template ratio, it is possible to tune the surface area and crystallite dimension of the Nb{sub 2}O{sub 5} films. The obtained T-Nb{sub 2}O{sub 5} films show typical capacitive-dominated behaviour in the sweep rate range of 1–20 mV s{sup −1}. It delivers an initial intercalation capacity of 644 C g{sup −1} at a current density of 0.625 A g{sup −1}, corresponding to x = 1.83 for Li{sub x}Nb{sub 2}O{sub 5}, and can still keep relatively stable capacity of 560 C g{sup −1} after 300 cycles. Moreover, its excellent high-rate capability (450 C g{sup −1} at 12.5 A g{sup −1}) and wider temperature adaptability present here suggests the promising of T-Nb{sub 2}O{sub 5} as high-energy pseudocapacitor electrode with superior intercalation capacitive behaviour. - Graphical abstract: We developed a facile and sustainable method to prepare T-Nb{sub 2}O{sub 5} nanocrystals using novel nanorod-like cellulose nanocrystals (CNs) as soft templates. The T-Nb{sub 2}O{sub 5} nanocrystals exhibited unprecedented Li{sup +} intercalation pseudocapacitance, excellent cycle performance and good high-and-low temperature tolerance performance.

  20. Viral persistence in surface and drinking water: Suitability of PCR pre-treatment with intercalating dyes.

    Science.gov (United States)

    Prevost, B; Goulet, M; Lucas, F S; Joyeux, M; Moulin, L; Wurtzer, S

    2016-03-15

    After many outbreaks of enteric virus associated with consumption of drinking water, the study of enteric viruses in water has increased significantly in recent years. In order to better understand the dynamics of enteric viruses in environmental water and the associated viral risk, it is necessary to estimate viral persistence in different conditions. In this study, two representative models of human enteric viruses, adenovirus 41 (AdV 41) and coxsackievirus B2 (CV-B2), were used to evaluate the persistence of enteric viruses in environmental water. The persistence of infectious particles, encapsidated genomes and free nucleic acids of AdV 41 and CV-B2 was evaluated in drinking water and surface water at different temperatures (4 °C, 20 °C and 37 °C). The infectivity of AdV 41 and CV-B2 persisted for at least 25 days, whatever the water temperature, and for more than 70 days at 4 °C and 20 °C, in both drinking and surface water. Encapsidated genomes persisted beyond 70 days, whatever the water temperature. Free nucleic acids (i.e. without capsid) also were able to persist for at least 16 days in drinking and surface water. The usefulness of a detection method based on an intercalating dye pre-treatment, which specifically targets preserved particles, was investigated for the discrimination of free and encapsidated genomes and it was compared to virus infectivity. Further, the resistance of AdV 41 and CV-B2 against two major disinfection treatments applied in drinking water plants (UV and chlorination) was evaluated. Even after the application of UV rays and chlorine at high doses (400 mJ/cm(2) and 10 mg.min/L, respectively), viral genomes were still detected with molecular biology methods. Although the intercalating dye pre-treatment had little use for the detection of the effects of UV treatment, it was useful in the case of treatment by chlorination and less than 1 log10 difference in the results was found as compared to the infectivity measurements

  1. Removal of Pb2+ from the aqueous solution by tartrate intercalated layered double hydroxides

    International Nuclear Information System (INIS)

    Shen, Yanming; Zhao, Xiaolei; Zhang, Xi; Li, Shifeng; Liu, Dongbin; Fan, Lihui

    2016-01-01

    Adsorption of Pb 2+ ion by a tartrate intercalated MgAl layered double hydroxides (MgAl-TA LDHs) was studied. The adsorption isotherms and kinetics were investigated as a function of various experimental parameters using batch adsorption experiments. The results indicated that the adsorption isotherm was well described by Sips model. The kinetic adsorption data were fitted well to the pseudo-second-order kinetic equation. The adsorption of Pb 2+ was controlled mainly by the chemical process combined with intraparticle diffusion. Parameters of adsorption thermodynamic suggested that the interaction of Pb 2+ adsorbed by MgAl-TA LDHs adsorbents was thermodynamically spontaneous and endothermic.

  2. Wnt5 is required for notochord cell intercalation in the ascidian Halocynthia roretzi.

    Science.gov (United States)

    Niwano, Tomoko; Takatori, Naohito; Kumano, Gaku; Nishida, Hiroki

    2009-08-25

    In the embryos of various animals, the body elongates after gastrulation by morphogenetic movements involving convergent extension. The Wnt/PCP (planar cell polarity) pathway plays roles in this process, particularly mediolateral polarization and intercalation of the embryonic cells. In ascidians, several factors in this pathway, including Wnt5, have been identified and found to be involved in the intercalation process of notochord cells. In the present study, the role of the Wnt5 genes, Hr-Wnt5alpha (Halocynthia roretzi Wnt5alpha) and Hr-Wnt5beta, in convergent extension was investigated in the ascidian H. roretzi by injecting antisense oligonucleotides and mRNAs into single precursor blastomeres of various tissues, including notochord, at the 64-cell stage. Hr-Wnt5alpha is expressed in developing notochord and was essential for notochord morphogenesis. Precise quantitative control of its expression level was crucial for proper cell intercalation. Overexpression of Wnt5 proteins in notochord and other tissues that surround the notochord indicated that Wnt5alpha plays a role within the notochord, and is unlikely to be the source of polarizing cues arising outside the notochord. Detailed mosaic analysis of the behaviour of individual notochord cells overexpressing Wnt5alpha indicated that a Wnt5alpha-manipulated cell does not affect the behaviour of neighbouring notochord cells, suggesting that Wnt5alpha works in a cell-autonomous manner. This is further supported by comparison of the results of Wnt5alpha and Dsh (Dishevelled) knockdown experiments. In addition, our results suggest that the Wnt/PCP pathway is also involved in mediolateral intercalation of cells of the ventral row of the nerve cord (floor plate) and the endodermal strand. The present study highlights the role of the Wnt5alpha signal in notochord convergent extension movements in ascidian embryos. Our results raise the novel possibility that Wnt5alpha functions in a cell-autonomous manner in

  3. Unconventional quantized edge transport in the presence of inter-edge coupling in intercalated graphene

    OpenAIRE

    Li, Yuanchang

    2016-01-01

    It is generally believed that the inter-edge coupling destroys the quantum spin Hall (QSH) effect along with the gap opening at the Dirac points. Using first-principles calculations, we find that the quantized edge transport persists in the presence of inter-edge coupling in Ta intercalated epitaxial graphene on SiC(0001), being a QSH insulator with the non-trivial gap of 81 meV. In this case, the band is characterized by two perfect Dirac cones with different Fermi velocities, yet only one m...

  4. Electron beam induced electronic transport in alkyl amine-intercalated VOx nanotubes

    International Nuclear Information System (INIS)

    O'Dwyer, C.; Lavayen, V.; Clavijo-Cedeno, C.; Torres, C.M.S.

    2008-01-01

    The electron beam induced electronic transport in primary alkyl amine-intercalated V 2 O 5 nanotubes is investigated where the organic amine molecules are employed as molecular conductive wires to an aminosilanized substrate surface and contacted to Au interdigitated electrode contacts. The results demonstrate that the high conductivity of the nanotubes is related to the non-resonant tunnelling through the amine molecules and a reduced polaron hopping conduction through the vanadium oxide itself. Both nanotube networks and individual nanotubes exhibit similarly high conductivities where the minority carrier transport is bias dependent and nanotube diameter invariant. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  5. Layered materials with improved magnesium intercalation for rechargeable magnesium ion cells

    Energy Technology Data Exchange (ETDEWEB)

    Doe, Robert Ellis; Downie, Craig Michael; Fischer, Christopher; Lane, George Hamilton; Morgan, Dane; Nevin, Josh; Ceder, Gerbrand; Persson, Kristin Aslaug; Eaglesham, David

    2016-07-26

    Electrochemical devices which incorporate cathode materials that include layered crystalline compounds for which a structural modification has been achieved which increases the diffusion rate of multi-valent ions into and out of the cathode materials. Examples in which the layer spacing of the layered electrode materials is modified to have a specific spacing range such that the spacing is optimal for diffusion of magnesium ions are presented. An electrochemical cell comprised of a positive intercalation electrode, a negative metal electrode, and a separator impregnated with a nonaqueous electrolyte solution containing multi-valent ions and arranged between the positive electrode and the negative electrode active material is described.

  6. From dihydrated iron(III) phosphate to monohydrated ammonium-iron(II) phosphate: Solvothermal reaction mediated by acetone-urea mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Alfonso, Belen F., E-mail: mbafernandez@uniovi.es [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n 33007 Oviedo (Spain); Trobajo, Camino [Departamento de Quimica Organica e Inorganica, Universidad de Oviedo-CINN, Julian Claveria 8, 33006 Oviedo (Spain); Pique, Carmen [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n 33007 Oviedo (Spain); Garcia, Jose R. [Departamento de Quimica Organica e Inorganica, Universidad de Oviedo-CINN, Julian Claveria 8, 33006 Oviedo (Spain); Blanco, Jesus A. [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n 33007 Oviedo (Spain)

    2012-12-15

    By reaction between synthetic phosphosiderite FePO{sub 4}{center_dot}2H{sub 2}O, urea (NH{sub 2}){sub 2}CO, and acetone (CH{sub 3}){sub 2}CO, we report a novel solvothermal synthesis of polycrystalline NH{sub 4}FePO{sub 4}{center_dot}H{sub 2}O. The preparation of other two individual phases, NH{sub 4}Fe{sub 2}(OH)(PO{sub 4}){sub 2}{center_dot}2H{sub 2}O and NH{sub 4}Fe{sub 2}(PO{sub 4}){sub 2}, is also described. The obtained product is a function of the reaction time and the N/P molar ratio in the reagent mixture, and the existence of structural memory in the dissolution-precipitation processes is discussed. Below 25 K, NH{sub 4}FePO{sub 4}{center_dot}H{sub 2}O behaves magnetically in a complex way, because both ferromagnetic and antiferromagnetic signals are superimposed, suggesting the existence of a canting of iron(II) magnetic moments. - Graphical abstract: Solvothermal synthesis of polycrystalline NH{sub 4}FePO{sub 4}{center_dot}H{sub 2}O is presented. The preparation of other two individual phases, NH{sub 4}Fe{sub 2}(OH)(PO{sub 4}){sub 2}{center_dot}2H{sub 2}O and NH{sub 4}Fe{sub 2}(PO{sub 4}){sub 2} as a function of the N/P molar ratio in the reagent mixture and the reaction time, is also described. Highlights: Black-Right-Pointing-Pointer Solvothermal synthesis of NH{sub 4}FePO{sub 4}{center_dot}H{sub 2}O from an Fe(III) phosphate: reduction process. Black-Right-Pointing-Pointer Formation of two intermediate metastable phases: phase diagram. Black-Right-Pointing-Pointer Thermal decomposition in two steps: mass loss of both water and ammonia. Black-Right-Pointing-Pointer Magnetic behaviour: AF+constant spontaneous magnetization.

  7. Hexagonal boron nitride intercalated multi-layer graphene: a possible ultimate solution to ultra-scaled interconnect technology

    Directory of Open Access Journals (Sweden)

    Yong-Jun Li

    2012-03-01

    Full Text Available We proposed intercalation of hexagonal boron nitride (hBN in multilayer graphene to improve its performance in ultra-scaled interconnects for integrated circuit. The effect of intercalated hBN layer in bilayer graphene is investigated using non-equilibrium Green's functions. We find the hBN intercalated bilayer graphene exhibit enhanced transport properties compared with pristine bilayer ones, and the improvement is attributed to suppression of interlayer scattering and good planar bonding condition of inbetween hBN layer. Based on these results, we proposed a via structure that not only benefits from suppressed interlayer scattering between multilayer graphene, but also sustains the unique electrical properties of graphene when many graphene layers are stacking together. The ideal current density across the structure can be as high as 4.6×109 A/cm2 at 1V, which is very promising for the future high-performance interconnect.

  8. Hexagonal boron nitride intercalated multi-layer graphene: a possible ultimate solution to ultra-scaled interconnect technology

    Science.gov (United States)

    Li, Yong-Jun; Sun, Qing-Qing; Chen, Lin; Zhou, Peng; Wang, Peng-Fei; Ding, Shi-Jin; Zhang, David Wei

    2012-03-01

    We proposed intercalation of hexagonal boron nitride (hBN) in multilayer graphene to improve its performance in ultra-scaled interconnects for integrated circuit. The effect of intercalated hBN layer in bilayer graphene is investigated using non-equilibrium Green's functions. We find the hBN intercalated bilayer graphene exhibit enhanced transport properties compared with pristine bilayer ones, and the improvement is attributed to suppression of interlayer scattering and good planar bonding condition of inbetween hBN layer. Based on these results, we proposed a via structure that not only benefits from suppressed interlayer scattering between multilayer graphene, but also sustains the unique electrical properties of graphene when many graphene layers are stacking together. The ideal current density across the structure can be as high as 4.6×109 A/cm2 at 1V, which is very promising for the future high-performance interconnect.

  9. Increasing the Analytical Sensitivity by Oligonucleotides Modified with Para- and Ortho-Twisted Intercalating Nucleic Acids - TINA

    DEFF Research Database (Denmark)

    Schneider, Uffe V; Géci, Imrich; Jøhnk, Nina

    2011-01-01

    -TINA molecules increased the melting point (Tm) of Watson-Crick based antiparallel DNA duplexes. The increase in Tm was greatest when the intercalators were placed at the 5' and 3' termini (preferable) or, if placed internally, for each half or whole helix turn. Terminally positioned TINA molecules improved......The sensitivity and specificity of clinical diagnostic assays using DNA hybridization techniques are limited by the dissociation of double-stranded DNA (dsDNA) antiparallel duplex helices. This situation can be improved by addition of DNA stabilizing molecules such as nucleic acid intercalators....... Here, we report the synthesis of a novel ortho-Twisted Intercalating Nucleic Acid (TINA) amidite utilizing the phosphoramidite approach, and examine the stabilizing effect of ortho- and para-TINA molecules in antiparallel DNA duplex formation. In a thermal stability assay, ortho- and para...

  10. Intercalation of Mg-ions in layered V2O5 cathode materials for rechargeable Mg-ion batteries

    DEFF Research Database (Denmark)

    Sørensen, Daniel Risskov; Johannesen, Pætur; Christensen, Christian Kolle

    The development of functioning rechargeable Mg-ion batteries is still in its early stage, and a coarse screening of suitable cathode materials is still on-going. Within the intercalation-type cathodes, layered crystalline materials are of high interest as they are known to perform well in Li-ion...... intercalation batteries and are also increasingly being explored for Na-ion batteries. Here, we present an investigation of the layered material orthorhombic V2O5, which is a classical candidate for an ion-intercalation material having a high theoretical capacity1. We present discharge-curves for the insertion...... discharge. This indicates that the degradation is highly associated with formation of ion-blocking layers on the anode....

  11. Protein intercalation in DNA as one of main modes of fixation of the most stable chromatin loop domains

    Directory of Open Access Journals (Sweden)

    М. I. Chopei

    2014-08-01

    Full Text Available The main mechanism of DNA track formation during comet assay of nucleoids, obtained after removal of cell membranes and most of proteins, is the extension to anode of negatively supercoiled DNA loops attached to proteins, remaining in nucleoid after lysis treatment. The composition of these residual protein structures and the nature of their strong interaction with the loop ends remain poorly studied. In this work we investigated the influence of chloroquine intercalation and denaturation of nucleoid proteins on the efficiency of electrophoretic track formation during comet assay. The results obtained suggest that even gentle protein denaturation is sufficient to reduce considerably the effectiveness of the DNA loop migration due to an increase in the loops size. The same effect was observed under local DNA unwinding upon chloroquine intercalation around the sites of the attachment of DNA to proteins. The topological interaction (protein intercalation into the double helix between DNA loop ends and nucleoid proteins is discussed.

  12. Optical contrast spectra studies for determining thickness of stage-1 graphene-FeCl{sub 3} intercalation compounds

    Energy Technology Data Exchange (ETDEWEB)

    Han, Wen-Peng, E-mail: han-wenpeng@163.com, E-mail: yunze.long@163.com; Yan, Xu; Zhao, Hui [College of Physics, Qingdao University, Qingdao 266071 (China); Li, Qiao-Qiao; Lu, Yan [State Key Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Long, Yun-Ze, E-mail: han-wenpeng@163.com, E-mail: yunze.long@163.com [College of Physics, Qingdao University, Qingdao 266071 (China); Collaborative Innovation Center for Low-Dimensional Nanomaterials and Optoelectronic Devices, Qingdao University, Qingdao 266071 (China)

    2016-07-15

    Because of novel features in their structural, electronic, magnetic and optical properties, especially potential applications in nanoelectronics, the few-layer graphene intercalation compounds (FLGICs) have been intensively studied recently. In this work, the dielectric constant of the doped graphene of stage-1 FeCl{sub 3}-GIC is obtained by fitting the optical contrast spectra. And fully intercalated stage-1 FeCl{sub 3}-FLGICs were prepared by micromechanical cleavage method from graphite intercalation compounds (GICs) for the first time. Finally, we demonstrated that the thickness of stage-1 FeCl{sub 3}-GICs by micromechanical cleavage can be determined by optical contrast spectra. This method also can be used to other FLGICs, such as SbCl{sub 5}-FLGICs and AuCl{sub 5}-FLGICs, etc.

  13. Synthesis of Various Polyaniline / Clay Nanocomposites Derived from Aniline and Substituted Aniline Derivatives by Mechanochemical Intercalation Method

    Directory of Open Access Journals (Sweden)

    N. Kalaivasan

    2010-01-01

    Full Text Available Polyaniline clay nanocomposite can be prepared by mechano-chemical method in which intercalation of anilinium ion into the clay lattices accomplished by mechanical grinding of sodium montmorillonite (Na+MMT in presence of anilinium hydrochloride at room temperature using mortar & pestle for about 30 min and subsequent grinding with oxidizing agent, ammonium peroxysulfate. The appearance of green colour indicates the formation of polyaniline/clay nanocomposite (PANI/Clay. Similarly aniline derivatives like o-toludine and o-anisidine in the form of HCl salt can form intercalation into the clay lattices. The intercalated aniline derivatives were ground mechanically in presence of oxidizing agent ammonium peroxysulfate lead to formation of substituted polyaniline/ clay nanocomposites. The characteristics of various polyaniline-clay nanocomposites were investigated using UV-Visible, FT-IR, cyclic voltammetry studies.

  14. Simultaneous Intercalation of 1-Naphthylacetic Acid and Indole-3-butyric Acid into Layered Double Hydroxides and Controlled Release Properties

    Directory of Open Access Journals (Sweden)

    Shifeng Li

    2014-01-01

    Full Text Available Controlled release formulations have been shown to have potential in overcoming the drawbacks of conventional plant growth regulators formulations. A controlled-release formulation of 1-naphthylacetic acid (NAA and indole-3-butyric acid (IBA simultaneous intercalated MgAl-layered double hydroxides (LDHs was prepared. The synthetic nanohybrid material was characterized by various techniques, and release kinetics was studied. NAA and IBA anions located in the gallery of MgAl-LDHs with bilayer arrangement, and the nanohybrids particles were of typical plate-like shape with the lateral size of 50–100 nm. The results revealed that NAA and IBA have been intercalated into the interlayer spaces of MgAl-LDHs. The release of NAA and IBA fits pseudo-second-order model and is dependent on temperature, pH value, and release medium. The nanohybrids of NAA and IBA simultaneously intercalated in LDHs possessed good controlled release properties.

  15. Tuning Fullerene Intercalation in a Poly (thiophene) derivative by Controlling the Polymer Degree of Self-Organisation

    Science.gov (United States)

    Paternò, G. M.; Skoda, M. W. A.; Dalgliesh, Robert; Cacialli, F.; Sakai, V. García

    2016-10-01

    Controlling the nanoscale arrangement in polymer-fullerene organic solar cells is of paramount importance to boost the performance of such promising class of photovoltaic diodes. In this work, we use a pseudo-bilayer system made of poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene (PBTTT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), to acquire a more complete understanding of the diffusion and intercalation of the fullerene-derivative within the polymer layer. By exploiting morphological and structural characterisation techniques, we observe that if we increase the film solidification time the polymer develops a higher crystalline order, and, as a result, it does not allow fullerene molecules to intercalate between the polymer side-chains. Gaining insight into the detailed fullerene intercalation mechanism is important for the development of organic photovoltaic diodes (PVDs).

  16. Ultrastructural and biochemical localization of N-RAP at the interface between myofibrils and intercalated disks in the mouse heart.

    Science.gov (United States)

    Zhang, J Q; Elzey, B; Williams, G; Lu, S; Law, D J; Horowits, R

    2001-12-11

    N-RAP is a recently discovered muscle-specific protein found at cardiac intercalated disks. Double immunogold labeling of mouse cardiac muscle reveals that vinculin is located immediately adjacent to the fascia adherens region of the intercalated disk membrane, while N-RAP extends approximately 100 nm further toward the interior of the cell. We partially purified cardiac intercalated disks using low- and high-salt extractions followed by density gradient centrifugation. Immunoblots show that this preparation is highly enriched in desmin and junctional proteins, including N-RAP, talin, vinculin, beta1-integrin, N-cadherin, and connexin 43. Electron microscopy and immunolabeling demonstrate that N-RAP and vinculin are associated with the large fragments of intercalated disks that are present in this preparation, which also contains numerous membrane vesicles. Detergent treatment of the partially purified intercalated disks removed the membrane vesicles and extracted vinculin and beta1-integrin. Further separation on a sucrose gradient removed residual actin and myosin and yielded a fraction morphologically similar to fasciae adherentes that was highly enriched in N-RAP, N-cadherin, connexin 43, talin, desmin, and alpha-actinin. The finding that N-RAP copurifies with detergent-extracted intercalated disk fragments even though beta-integrin and vinculin have been completely removed suggests that N-RAP association with the adherens junction region is mediated by the cadherin system. Consistent with this hypothesis, we found that recombinant N-RAP fragments bind alpha-actinin in a gel overlay assay. In addition, immunofluorescence shows that N-RAP remains bound at the ends of isolated, detergent-treated cardiac myofibrils. These results demonstrate that N-RAP remains tightly bound to myofibrils and fasciae adherentes during biochemical purification and may be a key constituent in the mechanical link between these two structures.

  17. Topotactic synthesis of the overlooked multilayer silicene intercalation compound SrSi2.

    Science.gov (United States)

    Tokmachev, A M; Averyanov, D V; Karateev, I A; Parfenov, O E; Vasiliev, A L; Yakunin, S N; Storchak, V G

    2016-09-28

    Silicene, a 2D honeycomb lattice of Si atoms similar to graphene, is expected to be a platform for nanoelectronics and home to novel quantum phenomena. Unlike graphene, free-standing silicene is notoriously difficult to stabilize, while strong hybridization of silicene with substrates destroys its desirable properties. On the other hand, Dirac cones of silicene are effectively realized in a bulk - stoichiometric ionic multilayer silicene intercalation compound CaSi2. Besides, a number of new 2D silicene-based materials are synthesized employing CaSi2 as a precursor. However, the rather complex atomic structure of CaSi2 and fresh opportunities of physical and chemical breakthroughs drive the search for alternative compounds with silicene networks. Here, a new polymorph of SrSi2 is synthesized, enjoying both the structure of intercalated multilayer silicene and the simplest possible stacking of silicene sheets. The MBE-quality synthesis accomplished on Si(001) and Si(111) surfaces leads to epitaxial films of SrSi2 with orientation controlled by the substrate, as revealed by XRD, RHEED and electron microscopy studies. The structural SrSi2/Si relation is mirrored in the transport properties of the films.

  18. Basic dye removal from aqueous solutions by dodecylsulfate- and dodecyl benzene sulfonate-intercalated hydrotalcite

    Energy Technology Data Exchange (ETDEWEB)

    Bouraada, Mohamed; Lafjah, Mama [Laboratoire de valorisation des materiaux, University of Mostaganem, B.P. 227, Mostaganem R.P. (Algeria); Ouali, Mohand Said [Laboratoire de valorisation des materiaux, University of Mostaganem, B.P. 227, Mostaganem R.P. (Algeria)], E-mail: ouali@univ-mosta.dz; Menorval, Louis Charles de [LAMMI (CNRS-UMR5072), Universite Montpellier II, 2 Place Eugene Bataillon, Case Courrier 015, 34095 Montpellier cedex 5 (France)

    2008-05-30

    Dodecylsulfate- and dodecyl benzene sulfonate-hydrotalcites were prepared by calcination-rehydratation method. The surfactants intercalation in the interlayer space of hydrotalcite were checked by PXRD and FTIR spectroscopy where the resulting materials were found to be similar to those reported in the literature and were used to remove a basic dye (safranine) from aqueous solutions. The sorption kinetics data fitted the pseudo second order model. The isotherms were established and the parameters calculated. The sorption data fitted the Langmuir model with good values of the determination coefficient. The thermodynamic parameters calculated from Van't Hoff plots gave a low value of {delta}G{sup o} (<-20 kJ mol{sup -1}) indicating a spontaneous physisorption process. Two regeneration cycles were processed by acetone extraction leading to the same removal capacity of the obtained materials as the original surfactant-intercalated hydrotalcites. The UV-vis spectra of the recovered extracts were similar to the spectrum of safranine, which means that the dye was recovered without any modification.

  19. Carboxylate-intercalated layered double hydroxides aged under microwave-hydrothermal treatment

    International Nuclear Information System (INIS)

    Benito, P.; Labajos, F.M.; Mafra, L.; Rocha, J.; Rives, V.

    2009-01-01

    Carboxylate-intercalated (terephthalate, TA and oxalate, ox) layered double hydroxides (LDHs) are aged under a microwave-hydrothermal treatment. The influence of the nature of the interlayer anion during the ageing process is studied. Characterization results show that the microwave-hydrothermal method can be extended to synthesize LDHs with anions different than carbonate, like TA. LDH-TA compounds are stable under microwave irradiation for increasing periods of time and the solids show an improved order both in the layers and in the interlayer region as evidenced by powder X-ray diffraction (PXRD), 27 Al MAS NMR and FT-IR spectroscopy. Furthermore, cleaning of the surface through removal of some organic species adsorbed on the surface of the particles also occurs during the microwave-hydrothermal treatment. Conversely, although the expected increase in crystallinity is observed in LDH-ox samples, the side-reaction between Al 3+ and ox is also enhanced under microwave irradiation, and a partial destruction of the structure takes place with an increase in the M 2+ /M 3+ ratio and consequent modification of the cell parameters. - Graphical Abstract: The influence of the nature of the interlayer anion during the ageing process of carboxylate-intercalated (TA and ox) hydrotalcite-like compounds (HTlcs) is studied. Well crystallized for TA-containing compounds were obtained. However, the non-desired side-reaction of ox with the aluminum of the layers is enhanced by the microwaves and a partial destruction of the structure takes place

  20. Neutron scattering investigation of layer-bending modes in alkali-metal--graphite intercalation compounds

    International Nuclear Information System (INIS)

    Zabel, H.; Kamitakahara, W.A.; Nicklow, R.M.

    1982-01-01

    Phonon dispersion curves for low-frequency transverse modes propagating in the basal plane have been measured in the alkali-metal--graphite intercalation compounds KC 8 , CsC 8 , KC 24 , and RbC 24 by means of neutron spectroscopy. The acoustic branches show an almost quadratic dispersion relation at small q, characteristic of strongly layered materials. The optical branches of stage-1 compounds can be classified as either graphitelike branches showing dispersion, or as almost dispersionless alkali-metal-like modes. Macroscopic shear constants C 44 and layer-bending moduli have been obtained for the intercalation compounds by analyzing the data in terms of a simple semicontinuum model. In stage-2 compounds, a dramatic softening of the shear constant by about a factor of 8 compared with pure graphite has been observed. Low-temperature results on KC 24 indicate the opening of a frequency gap near the alkali-metal Brillouin-zone boundary, possibly due to the formation of the alkali-metal superstructure