| Publications on the project |
049 Effect of Fractal Structure of Precursor on Formation of Ferrite and Particle Morphology of Nanosized M-type Barium Hexaferrite |
Authors: | Solovyova E.D., Pashkova E.V., Belous A.G. | |
Summary: | The effect of the fractal structure of precursors obtained by either precipitation of hydroxicarbonates or sol-gel technique on the phase transformations occurring during the synthesis and the morphology of nanodisperse M-type barium hexaferrite particles is studied. The optimal fractal structure is determined. Using of such a structure results in significant reduction of the single-phase temperature and makes possible fabrication of nanosize barium hexaferrite with the plate-like and rod-like shape anisotropy. | |
Keywords: | | |
Edition: | Nanosystems, nanomaterials and nanotechnologies | | | 2010,
971-982,Russian |
049 Fractal Structure of Precursors and Phase Transformations in the Sol–Gel Synthesis of Nanoparticulate M-Type Barium Hexaferrite |
Authors: | E. D. Solov’eva, E. V. Pashkova, and A. G. Belous | |
Summary: | We have studied the influence of sol–gel process conditions on the fractal structure of precursors,
the phase transformations during the synthesis process, and the morphology of the resulting barium hexaferrite particles and determined the optimal fractal structure of sol–gel derived precursors for the solid state synthesis of barium hexaferrite. The activity of the precursors is shown to correlate with the fractal dimension of their first structural aggregation level. Nanoparticulate barium hexaferrite can be prepared in the form of anisometric particles: platelets (dav ~ 65 nm) and nanorods (dav ~ 30 nm, lav ~ 70 nm). | |
Keywords: | | |
Edition: | Inorganic Materials | | | 2011,
1378–1383,Russian |
049 Effect of Preparation Conditions on Fractal Structure and Phase Transformations in the Synthesis of Nanoscale M-type Barium Hexaferrite |
Authors: | E.V. Pashkova, E.D. Solovyova, I.E.Kotenko, T.V. Kolodiazhnyi, A.G. Belous | |
Summary: | The conditions of the synthesis of carbonate-hydroxide precursors (pH of FeOOH precipitation and heat treatment regimes) were studied in terms of their effect on the fractal structure and physical–chemical properties of precursors. Phase transformations which occur during the synthesis of nanosize M-type barium hexaferrite (BHF) were studied as well.
The first structural level of precursors' aggregation for mass fractals, the correlation between fractal dimension and precursors' activity during the synthesis of BHF were determined.
Synthesis parameters for the precursors with the optimal fractal structure were determined. These data permit an enhancement of the filtration coefficient of the precipitates by a factor of 4–5, obtaining substantial decrease in the temperature required for synthesis of a single-phase BHF, and monodispersed plate-like nanoparticles (60 nm diameter) with the shape anisotropy and good magnetic characteristics (saturation magnetization (Ms)=68,7 emu/g and coercitivity (Hc)=5440 Oe). | |
Keywords: | Barium hexaferrite;
Precipitation;
Fractal structure;
Magnetic property;
Monodisperse nanoparticle | |
Edition: | Journal of Magnetism and Magnetic Materials | | | 2011,
2497–2503,English |
049 Synthesis of (Li,La){Ti,Nb}O3 by sol-gel method |
Authors: | S. Kobylianska, O. N. Gavrilenko, Yu. Gomza | |
Summary: | The method of sol–gel using chlorides and nitrates of metal nanoparticles have received litiumcontaining
lanthanum titanate and niobate the structure defective perovskyte. Shown that the formation of lithium titanate–lanthanum with average particles size d ~ 15 nm occurs at 700 oC. Unlike niobate formation perovskyte La0.5Li0.5TiO3 runs at one stage, without intermediate compounds, which is also uncharacteristic for other methods of synthesis of the complex oxide. | |
Keywords: | | |
Edition: | Ukrainian chemistry journal | | | 2010,
84-88,Ukrainian |
049 Synthesis, structure and properties of lithium ion conducting lanthanum niobates with defect perovskite structure |
Authors: | A.G. Belous, O.N. Gavrilenko, S.D. Kobilyanskaya, O.I. V’yunov, V.V. Trachevskii, O. Bohnke | |
Summary: | Solid solutions with defect perovskite structure have been obtained in the system Li0.5-yNayLa0.5 Nb2O6 at
0 ≤ y ≤ 0.5. It has been shown that when sodium ions substitute for lithium ions, an increase in the unit cell
volume of the defect perovskite is observed. The existence of lithium ions with different mobility in the system
Li0.5-yNayLa0.5 Nb2O6 (0 ≤ y < 0.5) has been shown by 7Li NMR. A percolation mechanism of the Li ion
diffusion is not observed in this system. The lithium-ion conductivity in Li0.5-yNayLa0.5 Nb2O6 (at y ≤ 0.43) is
higher in comparison with La0.5Li0.5Nb2O6. This may be due both to the increased amount of more mobile Li+
ions in the sodium-substituted samples and to the increase of the cell volume. The lithium-containing
lanthanum niobate La0.5Li0.5Nb2O6 has been obtained by the Pechini method. It has been shown that the
resistance of this sample is lower than that of a sample of the same composition prepared by the solid-state
reaction method. | |
Keywords: | Sodium-containing lithium–lanthanum niobate; Lithium ion mobility; Ionic transport; 7Li NMR; Pechini
method | |
Edition: | Chemistry of metals and alloys | | | 2010,
90-95,English |
049 Sol-gel synthesis and properties of tin-doped lanthanum manganites |
Authors: | A. I. Tovstolytkin, T. I. Polek, O. I. V’yunov, S. A. Solopan, A. G. Belous, A. F. Lozenko and P. A. Trotsenko | |
Summary: | The crystallographic, magnetic, electrical, and magnetoresistive properties of samples of La0,775Sr0,225Mn1–xSnxO3 synthesized by the sol-gel method are studied. It is shown that introducing tin atoms, with their large size, into the manganese sublattice produces significant deformations of the crystal lattice and enhances the structural and magnetic inhomogeneity of the samples. It is discovered that increasing the tin content leads to a reduction in magnetization, a lowering of the Curie temperature, and an increase in the electrical resistivity. The way the crystallographic parameters change is found to correlate with the character of the changes in the magnetic parameters. It is shown that the low-temperature magnetoresistance increases with x, while the magnetoresistance around room temperature is a nonmonotonic function of the tin concentration and has a maximum at x=0.015. | |
Keywords: | substituted manganites, tin doping, magnetic properties, magnetoresistance. | |
Edition: | Low Temperature Physics | | | 2011,
134-140,Russian |
049 Dielectric and Relaxor Properties of Ba9MNb14O45 Ceramics |
Authors: | O. Ovchar, D. Durilin, A. Belous, B. Jančar, T. Kolodiazhnyi | |
Summary: | The ceramics with two types of nominal compositions including (6:1:4.5) Ba6M2+Nb9O29.5 and (9:1:7) Ba9M2+Nb14O45 (M = Mg, Co, Zn) have been synthesized and studied with regard to their phase composition and dielectric properties. The materials with Ba6M2+Nb9O29.5 nominal compositions corresponded to the two-phase region containing 9:1:7 tetragonal tungsten bronze-type (TTB) phase and the 3:1:1 perovskite Ba(M2+1/3Nb2/3)O3. In contrast, 9:1:7 TTB ceramics were near single phase. All of the studied 9:1:7 TTB phases exhibited high values of dielectric permittivity (ε = 800–1100) together with strong frequency dispersion. The observed dispersion of permittivity was accompanied by the monotonic rise of dielectric loss. The dielectric spectra of 9:1:7 TTBs demonstrated a typical relaxor behavior. At low temperatures (100–300 K), two relaxation modes have been found in the tan δ (T) dependencies, which can be associated with two different types of structural disorder in the TTB crystal lattice. | |
Keywords: | | |
Edition: | Journal of the American Ceramic Society | | | 2012,
3202–3206,English |
049 Synthesis and nonlinear properties of the AgNb1–xTaxO3 solid solutions |
Authors: | O. Suslov, D. Durylin, O. Ovchar, A. Belous | |
Summary: | The polycrystalline tunable materials based on solid solutions AgNb1–xTaxO3 (ANT) with perovskite structure have been obtained and chemical transformations of their solid phase synthesis have been studied. The effect of low-melting additives Zn2TiO4 and ZnB2O4 on the temperature of sintering of ceramics ANT, its phase composition and microstructure has been determined. First, by introducing a low-melting additive Zn2TiO4 and ZnB2O4 in ANT, during sintering in air single-phase dense ceramics with high dielectric properties was obtained (e ~400—470, tg d ~10–2). It was found that in case of 1—2 wt. % Zn2TiO4 value of the relative coefficient of tunability nR of materials achieves ~10 % at relatively low field strength (Е = =3.106 V/m). | |
Keywords: | perovskites, light-melting additives, nonlinear materials, dielectric properties | |
Edition: | Ukraine Chemical Journal | | | 2013,
3-8,Ukrainian |
049 Nanosised nonlinear materials based on the Ba0,6Sr0,4TiO3 |
Authors: | O. Suslov, D. Durylin, O. Ovchar, A. Belous, B. Jancar | |
Summary: | Composite materials based on Ba0.6Sr0.4TiO3 solid solution with different contents of Mg-containing impurities (MgO and Mg2TiO4) are fabricated. Their phase composition, dielectric and nonlinear properties are investigated. Composite thin films based on Ba0.6Sr0.4TiO3–MgO (1 wt.%) are synthesized by the sol–gel technique on substrates of polycrystalline Al2O3. Phase composition, microstructure and effect of heat-treatment conditions on the quality of films are studied. | |
Keywords: | nonlinear dielectrics, composite materials, sol-gel synthesis, thin films, microstructure. | |
Edition: | Nanosystems, Nanomaterials, Nanotechnologies | | | 2014,
323-331,Ukrainian |
049 Patent. The preparation method of thin dense films of M-type barium hexaferrite |
Authors: | Bilous A.G., Solovyova E.D., Pashkova E.V., Khomenko B.S. | |
Summary: | A method of preparation of thin dense films of M-type barium hexaferrite (BHF), which can be used to produce high density films for low noise systems of magnetic recording, as well as for microwave devices. | |
Keywords: | | |
Edition: | Ukrainian patent No 83428, publ. 10/09/2013 | | | 2013,
1-7,Ukrainian |
049 Zirconium Concentrate Autoclave Decomposition at the Presence of Calcium Fluoride |
Authors: | Pavlenko T.V., Rudkovska L.M., Omelchuk A.O, Onishchuk S.F. | |
Summary: | The process of zirconium concentrate autoclave decomposition by sodium hydroxide solution
at the presence of calcium fluoride for zirconium dioxide production is investigated.
The process optimal conditions are determined and the resulting products properties are
explored. It is displayed that the proposed method allows to achieve 96–99 % degree of
zirconium concentrate decomposition with energy and resources consumption decrease in
comparison with known methods. | |
Keywords: | zirconium concentrate, autoclave decomposition, sodium fluorozirconates, sodium hydroxide, calcium fluoride, zirconium dioxide. | |
Edition: | Environmental Technology and Resources Saving | | | 2010,
50-53,Ukrainian |
049 Phase transformations in LnF3–(Ln, Zr)–ZrF4 systems, where Ln = Sm, Eu, Tm, Yb |
Authors: | Kompanichenko N.M, Omel’chuk A.O., Ivanenko O.P., Zinchenko V.F. | |
Summary: | Phase transformations in LnF3–(Ln, Zr)–ZrF4 systems (where Ln = Sm, Eu, Tm, Yb) in the temperature range 700–900 °C have been investigated by chemical and X-ray phase analyses, UV and IR spectroscopy. Synthesis conditions of nonstoichiometric samarium, europium, ytterbium and thulium fluorides, which are products of interaction between LnF3 and Ln and original substances for the preparation of compounds such as LnZrF6 are given. The crystal lattice of the fluorozirconates obtained is similar to the Yb27F64 superstructure. Thulium fluorozirconate (TmZrF6), whose structure is indexed as the Tm13F32−δ superstructure of hexagonal system, is an exception. For all compounds obtained, the lattice parameters have been calculated and the absorption bands of IR spectra have been interpreted. | |
Keywords: | Rare-earth fluoride;
Zirconium fluoride;
Nonstoichiometric compounds;
Phase transformations;
IR spectroscopy;
Electronic diffuse reflection spectra | |
Edition: | Journal of Fluorine Chemistry | | | 2010,
282-287,English |
049 Electrochemical Dispersion of Metals |
Authors: | Blyznyuk A.V., Litovchenko V.D. | |
Summary: | The results of electrochemical dispersion of group IV metals in solution of sulfuric acid and sodium hydroxide with polarization of DC and industrial frequency AC have been shown. The dispersion under DC is required pre-activation of surface of electrode matrix. The composition of the powder formed depends on the synthesis conditions. | |
Keywords: | | |
Edition: | Issues of Chemistry and Chemical Technology | | | 2011,
68-71,Ukrainian |
049 Nanostructured Zirconia Synthesized by Hydrothermal Method from Decomposition Products of Zirconium Concentrate |
Authors: | Rudkovskaja L.M., Pavlenko T.V., Pshenichnij R.N., Omelchuk A.A. | |
Summary: | Hydrothermal synthesis of nanostructured zirconia powders from zircon-concentrate decomposition products with alkaline solutions of different concentration in the presence of calcium fluoride is developed. The effects of chemical prehistory (phase composition of zircon-concentrate decomposition products), the method for the preparation of initial zirconium-hydroxide gel, and hydrothermal-synthesis parameters on the morphology and microstructure of the obtained nanocrystalline zirconia powders are established. The optimal synthesis conditions are determined. As found, the zirconium hydroxide obtained from dissolved zircon-decomposition products with preliminary separation of silicic acid crystallizes under hydrothermal conditions mainly as monoclinic zirconia modification. However, if zirconium hydroxide precipitates from acid solutions of decomposition products with- out separation of silicic acid, mainly the tetragonal form of zirconia crystallizes from such hydroxides. The nanocrystalline zirconia samples obtained are investigated by means of both x-ray phase analysis (XPA) and electron microscopy. | |
Keywords: | nanostructural zirconia, hydrothermal synthesis, zircon concentrate, decomposition, zirconium hydroxide | |
Edition: | Nanosistemi, Nanomateriali, Nanotehnologii | | | 2012,
351-360,Russian |
049 Role of Hydride Formation in Cathode Destruction of Lead Electrode Matrix in Sulfuric Acid Solutions |
Authors: | Kozin V.F., Blyznyuk A.V., Litovchenko V.D. | |
Summary: | The paper presents results of studies of the cathodic breakdown of lead electrodes in sulfuric acid solutions. The kinetic parameters of hydrogen evolution at a lead cathode: transfer coefficients αк, Theoretical and experimental angular coefficients bth and bexp, exchange currents io, hydrogen evolution overpotential (ηоН2 = 1.05 V) have been determined, and the value of activation energy (ЕηΗ2 = 39.31 kJ/mol) has been calculated. It has been shown that the cause of the breakdown of electrode matrix is the formation of lead hydrides. Experimental data on the formation of PbHads and PbH2 on the cathodic polarization of lead electrode are presented. A mechanism of the reduction of hydrogen during the formation of lead hydrides on lead cathode is proposed. | |
Keywords: | | |
Edition: | Ukrainian Chemistry Journal | | | 2013,
40-47,Russian |
049 Interaction of Zirconium with Salt Melts |
Authors: | Bugaenko V.V., Gritsay L.V. | |
Summary: | Temperature dependence of compact zirconium interaction with low melting temperature melts of the systems NaCl—KCl, CaO—CaCl2—NaCl, KBF4—NaCl—KCl, NaCl—KCl—K2SiF6 has been investigated. Solubility of Na2ZrF6 and ZrO2 in eutectic melt of the system CaO—CaCl2—NaCl has been defined. | |
Keywords: | | |
Edition: | Ukrainian Chemistry Journal | | | 2014,
81-84,Ukrainian |
049 Conductivity of nonstoichiometric fluorides LnF2+x (Ln = Sm, Eu, Yb) |
Authors: | N. M. Kompanichenko, A. A. Omel’chuk, A. P. Ivanenko, R. N. Pshenichnyi, E. V. Timukhin | |
Summary: | Nonstoichiometric fluorides LnF2+x (Ln = Sm, Eu, Yb) were synthesized by reduction of trifluorides with the above rare-earth elements. The resulting phases were identified by chemical and X-ray phase analyses, their composition and structure were determined, and their lattice constants were found. The ac bridge method at a frequency of 70 kHz was used to study the conductivity of the synthesized compounds and starting trifluorides in the temperature range 773–298 K. The temperature dependence of the conductivity of these compounds is satisfactorily approximated by the Arrhenius-Frenkel equation. A kink is observed on the plots of the electrical conductivity against temperature for all compounds. With decreasing content of fluorine, this kink shifts to higher temperatures. The highest conductivity is observed for the phases with low crystal packing density. With increasing content of fluorine, the conductivity of all nonstoichiometric phases not belonging to substitution solid solutions approaches the conductivity of the corresponding trifluorides. | |
Keywords: | | |
Edition: | Russian Journal of Applied Chemistry | | | 2013,
1887-1893,Russian |
049 Tailored nanostructured zirconia polymorphs are prepared from zircon concentrate decomposition products |
Authors: | L. M. Rudkovskaya, T. V. Pavlenko, R. N. Pshenichny, A. A. Omel’chuk, A. A. Vishnevsky
| |
Summary: | We report on the hydrothermal synthesis of nanodisperse zirconia powders from the products of zircon concentrate decomposition by alkali solutions of various concentrations in the presence of calcium fluoride. Either tetragonal or monoclinic zirconia, or mixtures of both can be prepared depending on the chemical and phase composition of the zircon concentrate decomposition products and on the conditions under which amorphous zirconium hydroxide gel was prepared. The tetragonal phase is stabilized by calcium ions contained in the initial solutions. | |
Keywords: | | |
Edition: | Russian Journal of Inorganic Chemistry | | | 2014,
439–444,Russian |
049 Патент. Спосіб одержання високодисперсного порошку індію високої чистоти |
Authors: | Kozіn V.H., Omelchuk A.O., Bliznyuk A.V. | |
Summary: | Method for producing indium fine-powder of high purity by chemical dispersion, which is carried out by AC industrial frequency polarization of indium electrode in a solution of sodium hydroxide with a concentration of 0.1 - 4 mol/L at the current density of 3-8 A/cm2. | |
Keywords: | | |
Edition: | Ukrainian patent No 74650, publ. 12/11/2012 | | | 2012,
1-5,Ukrainian |
049 Patent. A method for producing ultrafine high purity bismuth plates |
Authors: | Kozin V.H., Litovchenko V.D., Bliznyuk A.V. | |
Summary: | A method for producing ultrafine high purity bismuth plates including dispersion by electron flow and polarization of bismuth by direct current in a solution containing concentrated perchloric acid and aluminum perchlorate has been described. | |
Keywords: | | |
Edition: | Ukrainian patent No 73612, publ. 25/09/2012 | | | 2012,
1-5,Ukrainian |
049 Investigation of Electrocatalytic Properties of Nanostructured Composites for Chemical Current Sources |
Authors: | Danilov M.O., Rusetskyy I.A., Slobodyanyuk I.A. | |
Summary: | Nanocomposites based on carbon nanotubes with deposited catalysts have been prepared and investigated in the oxygen electrode. The “a” coefficients in Tafel equation for the formation of molecular oxygen in these catalysts have been determined. The characteristics of the oxygen electrode have been found to depend on the “a” coefficient for the oxygen evolution reaction. This fact has been explained, and the possibility of predicting the catalytic properties of materials has been suggested. | |
Keywords: | | |
Edition: | Issues of Chemistry and Chemical Technology | | | 2011,
145-147,Russian |
049 Electrocatalysis on Nanocomposites in Oxygen Electrode of Low-Temperature Fuel Cells |
Authors: | M.O. Danilov, I.A. Slobodyanyuk, G.Ya. Kolbasov, I.A. Rusetskii | |
Summary: | Nanocomposites are fabricated from carbon nanotubes with supported cata-lysts, which are investigated as the oxygen electrodes. The coefficients а in the Tafel equation for the evolution of molecular oxygen on these catalysts are determined. Dependence of the oxygen electrodes characteristics on magnitude of the а coefficient for oxygen-evolution reaction on catalysts is revealed. The explanation is proposed and the possibility of predicting the catalytic properties of materials is suggested. | |
Keywords: | | |
Edition: | Physics of Metals and Advanced Technologies | | | 2011,
75-84,Russian |
049 Electrocatalytic Properties of Nanocomposites for Electrochemical Power Sources From the Standpoint of Localization of Reactions |
Authors: | Danilov M.O., Kolbasov G.Ya., Rusetskii I.A., Slobodyanyuk I.A. | |
Summary: | Nanocomposites of carbon nanotubes with deposited catalysts have been obtained, which were investigated in oxygen electrodes. The coefficients α of Tafel equation for molecular oxygen evolution at these catalysts have been determined. A dependence of oxygen electrode characteristics on the value of the coefficient α for oxygen evolution reaction has been discovered. This phenomenon has been explained in terms of localization of electrochemical reactions at the catalyst and support, and the assumption has been made that the catalytic properties of materials can be predicted. | |
Keywords: | | |
Edition: | Еlectrochemical Society Transaction | | | 2012,
133–137,English |
049 Photoelectrochemical Properties of Nanostructured Photoelectrodes TiO2/CdSe for Systems of Hydrogen Production |
Authors: | I.A. Slobodyanyuk , I.A. Rusetskii, G.Ya. Kolbasov | |
Summary: | Semiconductor heterostructures NT-TiO2/CdSe have been obtained by supporting semiconductor films CdSe on
a Ti-substrate with the generated layer of nanotubes TiО2
by potentiostatic anodic polarisation. Photoelectrochemical processes on polycrystalline NT-TiO2/CdSe-photoelectrodes have been studied. The reasons of increase in efficiency of phototransformation after inoculation of a surface of photoelectrodes by Pt and Zn nanoparticles have been analyzed. It has been shown that nanostructurization of electrodes leads to increase in their photosensitivity what is connected with decrease in surface recombination speed. Overall efficiency of photoanodes studied in a photoelectrochemical cell with hydrogen accumulation has been examined. | |
Keywords: | | |
Edition: | Chemistry, Physics and Technology of Surface | | | 2012,
330-334,Russian |
049 Electrocatatytic Properties of Reduced Graphene Oxide in Oxygen Electrode |
Authors: | M.O. Danilov, G.Ya. Kolbasov, I.A. Rusetskii, I.A. Slobodyanyuk | |
Summary: | Reduced graphene oxide obtained by oxidation of multiwalled carbon nanotubes followed by reduction with sodium hypophosphite and sodium sulfite. X-ray diffraction and electron microscopy showed that the resulting product is reduced graphene oxide. Reduced graphene oxide has been investigated as an electrode material for oxygen electrodes of fuel cells. It has been shown that reduced graphene oxide obtained by the oxidation of multiwalled carbon nanotubes with subsequent reduction with sodium hypophosphite is a promising material for fuel cell oxygen electrodes and does not require the use of highly toxic reagents. | |
Keywords: | | |
Edition: | Proceeding of 13-th ABAF Advanced Batteries, Accumulators and Fuel Cells | | | 2012,
17–22,English |
049 Electrocatalytic Properties of Catalysts Deposited on Carbon Nanotubes, for Oxygen Electrodes of Chemical Current Sources |
Authors: | I.A. Slobodyanyuk, M.O. Danilov, I.A. Rusetskii, G.Ya. Kolbasov | |
Summary: | Nanocomposite electrocatalytic materials on the basis of multiwall carbon nanotubes with
metals (Pt, Ni, Pb), oxides (manganese, molybde
num, chromium, cobalt, niobium) and cadmium
sulphide are gained. Correlation catalytic activity of
electrodes from magnitude of the coefficient «a» in
the equation for Tafel reaction of
oxygen evolution is detected. It is assumed that adsorption of a
reagent and carrying over electrons are localized
and proceed in parallel on the catalyst and the
carrying agent, and reagent particles diffuse throug
h a catalyst and carrying agent phase boundary.
The leading-out is drawn that for carbon nanotubes, with a low adsorption energy of oxygen, it is necessary to apply the catalyst with a high adsorpt ion energy of molecular oxygen, and consequently with great value of an overst rain in allocation reaction to it of molecular oxygen. | |
Keywords: | | |
Edition: | Surface | | | 2012,
134-141,Russian |
049 Electrocatalytic Properties of Multiwalled Carbon Nanotubes-Based Nanocomposites for Oxygen Electrodes |
Authors: | M. O. Danilov, G. Ya. Kolbasov, I. A. Rusetskii, I. A. Slobodyanyuk | |
Summary: | Metals (platinum, nickel, and lead) and oxides (manganese dioxide and molybdenum, chromium, cobalt, and niobium oxides) were deposited onto multiwalled carbon nanotubes by chemical and electrochemical methods. The resulting nanocomposites were tested as oxygen electrode materials for electrochemical power sources with alkaline electrolytes. A correlation was revealed between the catalytic activity of oxygen electrodes manufactured from composites based on carbon nanotubes with catalyst deposited, on the one hand, and the coeffi cient a in the Tafel equation for the oxygen evolution reaction on this catalyst, on the other. A possibility of predicting and evaluating the catalytic properties of oxygen electrode materials for power sources was suggested. | |
Keywords: | | |
Edition: | Russian Journal of Applied Chemistry | | | 2012,
1601–1605,Russian |
049 Reduced graphene oxide: a promising electrode material for oxygen electrodes |
Authors: | Danilov M.O., Slobodyanyuk I.A., Rusetskii I.A., Kolbasov G.Ya. | |
Summary: | A method for the chemical synthesis of reduced graphene oxide has been developed. It is based on the chemical oxidation of multiwalled carbon nanotubes by means of heptavalent manganese with subsequent reduction. Sodium hypophosphite and sulfite were used as reductants. It has been confirmed by different methods that reduced graphene oxide is obtained. Current-potential curves for electrodes based on reduced graphene oxide in an oxygen fuel cell mock-up with alkaline electrolyte have been studied. It has been found that the characteristics of the electrode of graphene oxide reduced with sodium hypophosphite in oxygen reduction reaction are three to four times higher than those of the electrode of starting multiwalled carbon nanotubes. The electrodes based on reduced graphene oxide are superior to multiwalled carbon nanotube-MnO2 composite in characteristics. The characteristics of oxygen electrodes based on reduced graphene oxide were stable during 6-month tests. The reduced graphene oxide obtained promises much as a material for the oxygen electrodes of electrochemical power sources. | |
Keywords: | Reduced graphene oxide; Electrocatalysis; Oxygen electrode; Electrochemical power sources | |
Edition: | Journal of Nanostructure in Chemistry | | | 2013,
1-5,English |
049 Physical and chemical properties and photocatalytic activity of nanostructured TiO2/CdS films |
Authors: | Zhukovskiy M.A., Smirnova N.P., Rusetsky I.A., Kolbasov G.Ya., Eremenko A.M. | |
Summary: | Mesoporous titanium dioxide films obtained by the sol/gel template method are used as supports for making TiO2/CdS nanoheterostructures. We show that the photocatalytic method results in formation of smaller CdS nanoparticles than chemical deposition. Photoelectrochemical measurements show more efficient spatial separation of photogenerated charges between components of the photocatalytically produced TiO2/CdS films, and consequently their participation in redox transformation of the xanthene dye Rose Bengal when exposed to UV light leads to higher quantum yields. | |
Keywords: | mesoporous film, photochemical deposition, TiO2/CdS nanostructure, photocatalysis, Rose Bengal | |
Edition: | Journal of Applied Spectroscopy | | | 2014,
238-243,English |
049 Patent. Photoelectrochemical Element with Li-Conducting Membrane for Hydrogen Allocation |
Authors: | Slobodyanyuk I.A., Rusetsky I.A., Kolbasov G.Ya., Kobilyanskaya S.D., Bilous A.G. | |
Summary: | Photoelectrochemical element for hydrogen allocation consists of semiconductor CdSe-photoelectrode and two Pt electrodes in electrolytes with different pH which are separated by Li-conducting ceramic membrane. Anode electrode space is the solution of sodium sulfide, sodium hydroxide and lithium hydroxide, whereas the cathode electrode space is the solution of sulfuric acid and lithium sulfate. | |
Keywords: | | |
Edition: | Ukrainian patent No 73554, publ. 25/09/2012 | | | 2012,
1-4,Ukrainian |
049 049 Synthesis of Catalytic Active Substrates for Obtaining of Nanostructures of Germanium (IV) |
Authors: | M.N. Doroshenko, O.V.Naboka, Y.A.Mazurenko , V.M. Ogenko | |
Summary: | The prospects of nanomaterials based on germanium in nanoelectronics are presented. The properties of germanium nanostructures (GeNTs) were shown to correlate with theoretical calculations. To overcome the difficulty of GeNTs formation on the open surface, the template synthesis of coordination compounds of germanium (b-diketonates) by rf PE MOCVD method was proposed, during which organometallic chemical vapor deposition is activated by high-frequency plasma using a catalytically active substrates and volatile precursors. It was shown that the nanoporous silica and aluminum oxide matrices with catalytically active nanoparticles of cobalt oxides and gold on the surface can be synthesized by thermal evaporation in vacuum (TEV). | |
Keywords: | Chemical vapor deposition, modeling, creation of nanostructures, nanoclusters, nanotubes, precursors of metal coordination compounds | |
Edition: | Ukrainian Chemistry Journal | | | 2011,
94-99,Russian |
049 Nanostructure morphology formed by chemical vapor deposition from coordination compounds of metals |
Authors: | A.I.Gerasimchuk, L.I. Zheleznova, Y.A.Mazurenko, N.Murafa, J.Shubrt | |
Summary: | The theoretical analysis of the impact of micro-kinetic factors
which influencing the nanostructure morphology formed by chemical vapor deposition from coordination compounds of metals are made. Conditions are formulated fractal branched or crystal growth and formation of 0D, 1D, 2D, 3D objects. For the experiment, selected samples of coatings on silicon substrates obtained by plasma CVD, and we spray-pyrolysis of various coordination precursors. Investigation by scanning electron microscopy and high resolution electron microscopy shows that the chemical composition and morphology of different parts formed as a result of regular nano-island structures are different and correspond to the proposed theoretical model. | |
Keywords: | CVD, β-diketonates, sedimentation, electron microscopy, nanostructure, morphology | |
Edition: | Nanostructured Material Science | | | 2010,
24-38,Russian |
049 RF PE MOCVD-Synthesis and Morphological Characteristics of Germanium Nanoparticles |
Authors: | Doroshenko M.N., Zheleznova L.I., Mazurenko Ye.A. | |
Summary: | The germanium nanoparticles (GeNPs) has been synthesised by RF PE MOCVD using b-diketonate complexes of germanium (IV) as precursors and different types of catalytically-activated substrates. The optimum temperature synthesis of nanoparticles is found to be 120 оC, which is 200—330 oC lower than for the usual CVD synthesis of similar nanostructures. The morphological properties of the GeNPs has been studied by scanning electron microscopy (SEM). It was shown that the size of the nanoparticles varies in the range from 10 to 800 nm depending on the type of substrate. | |
Keywords: | CVD, β-diketonates, sedimentation, electron microscopy, nanostructure, morphology | |
Edition: | Ukrainian Chemistry Journal | | | 2012,
75-78,Russian |
049 Synthesis and properties of dihydroxy-bis-1,1,1,5,5,5-hexafluoro-2,4-pentandionate germanium(IV) — precursors for nanostructures |
Authors: | Doroshenko M.M., Zheleznova L.I., Mazurenko Y.A. | |
Summary: | The synthesis and diagnostics dihydroxy-bis-1,1,1,5,5,5-hexafluoro-2,4-pentandionate germanium(IV) — the precursor of nanostructures is carried out. Elemental analysis showed that molar ratio of Ge compound : ligand = 1:2. The results of NMR, IR spectroscopy, thermogravimetry and mass spectrometry allowed the determination of the structure of the complex, the type of ligands coordination, thermal characteristics and the features of complex destruction. The results show the promise of using the prepared compound as a precursor in the synthesis of germanium nanostructures. | |
Keywords: | CVD, β-diketonates, sedimentation, electron microscopy, nanostructure, morphology | |
Edition: | Ukrainian Chemistry Journal | | | 2012,
79-82,Russian |
049 Catalytic Effect of Surface on PE MOCVD-Synthesis of Germanium Nanotubes |
Authors: | Doroshenko M.N., Gerasimchuk A.I., Mazurenko E.A. | |
Summary: | Quantum chemical calculations of the coordination compound of Ge(IV) with Hhfa by PM3 have been carried out. The only stable compound has been found to be a complex with composition Ge(hfa)2(OH)2. Porous substrates based on anodic alumina (pore d ~70–150 nm) were synthesized with following deposition of Au nanoclusters (d ~ 5–10 nm)on their surface. It has been shown that using of templates based on Al/Al2O3/Au promotes the formation of germanium nanotubes due to the adsorption-desorption of germanium atoms by surface of Au nanoclusters (VLS-mechanism). PE MOCVD-synthesis (120 °C) of germanium nanotubes of different diameters (~70–180 nm) and shape (homogeneous and curved) using a volatile complex Ge(hfa)2(OH)2 was carried out. | |
Keywords: | Germanium nanotubes, volatile precursor, catalytically active surface, CVD-synthesis, low-temperature plasma | |
Edition: | Chemistry, Physics and Technology of Surface | | | 2013,
366-372,Russian |
049 Molecular design of implantation processes of cobalt nanostructures on surface of carbon micro- and nano-objects |
Authors: | Gerasimchuk A.I., Zheleznova L.I., Rogovtsov O.O., Trunova O.K. | |
Summary: | The theoretical analysis of interaction of Со(АА)2G2 precursor fragmentation products which appear at the chemical vapor deposition with the nanotubular and diamond-like carbon structures were carried out. The formation conditions of cobalt as a product of destruction of the complex precursor on these surfaces were determined. For an experiments, samples of coverages on a synthetic diamond (size of particles of 50 mkm) and on carbon nanotubes, which were prepared by different methods (plasma-chemical, spray-pyrolysis and impregnation of sample by solution of precursor with further annealing) were selected. Scanning electron microscopy and high resolution electron microscopy shown that chemical composition and morphology of metal-oxide cobalt structures agreed with the proposed theoretical model. | |
Keywords: | | |
Edition: | Ukrainian Chemistry Journal | | | 2014,
9-13,Ukrainian |
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049 Bilous Anatoliy G.Academician of NAS of Ukraine Deputy Academician-Secretary, Department of Chemistry +38044424-2211
049 2.2. Chemistry and electrochemistry nanoheterostructures and hybrid nanocomposites Purpose:Development of scientific principles of functional nanostructured materials based on complex oxides. Establishing the interrelation between structural features, electrophysical properties and preparation methods. Investigation of the effect of non-stoichiometry in the cation sublattices, and fractal structure formed by nanoparticles during the synthesis from solutions, of ion-conducting, dielectric and ferromagnetic mixed oxides on the dimension of nanoheterostructures prepared based on nanoparticles; establishing the effect of structural features of nanoheterostructures on electrophysical, catalytic, and optical properties of materials. Expected results:Release of new product: material Stage 1:Investigation of fractal structure, which is formed during sol-gel synthesis by nanoparticles of lithium-conducting materials based on complex oxides (La,Li)(Ta,Nb,Ti)O3; synthesis of nanoheterostructures based on lithium-conducting films. Hydrothermal synthesis of nanostructured zirconium dioxide using domestic raw materials. Development of methods of synthesis of nanoheterostructures and nanocomposites based on carbon nanotubes and oxides of transition metals (Mo, W, Co, Ni) and investigation of the effect of synthesis conditions on the structure of the material prepared. Development of precursors for PE MOCVD synthesis of germanium nanotubular structures. Stage 2:Investigation of fractal structures formed by nanoparticles in sol-gel synthesis of ferromagnetic materials with barium hexaferrite and perovskite structures and preparation of nanoheterostructures based on ferromagnetic films. Structural features and properties of zirconia synthesized by hydrothermal method. Modifying nanoheterostructures and nanocomposites, based on carbon nanotubes and metal oxide, by nanoparticles of metals and semiconductors and investigation the effect of modifiers on the photo- and electrocatalytic activity of nanomaterials. Synthesis of germanium nanotubular structures by REMOCVD. Investigation of the mechanism and kinetics of their formation. Stage 3:Investigation of the effect of cationic sublattice non-stoichiometry on the formation of nanoheterostructures in compounds with complex cationic sublattice (Ag(Nb,Ta)O3; Ba(A1/3Nb2/3)O3, A = Co, Zn, Mg). Synthesis of metal-oxide compositions based on lead with polarization by industrial frequency alternating current. Synthesis of electrode materials based on titanium dioxide dispersed and modified by nanoparticles and ions of metals (Ag, Au, La, Ni) and organic dyes (eosin, phthalocyanines, etc.); investigation of photoelectrochemical characteristics; investigation of non-stoichiometric nanocomposites in oxygen reduction reaction. Synthesis of germanium nanotubular structures by spray pyrolysis. The investigation of the effect of synthesis conditions on the structure of the material prepared. Stage 4:Investigation of the effect of the type of fractal structures on the dimension of heterostructures obtained from nanoparticles. Investigation of the effect of cation composition of fluoride zirconate melts on the solubility of REE oxides. Making of electrodes based on CdSe and CdSexTe1-x/modified TiO2 nanoheterostructures, investigation of their photo- and electrochemical characteristics. The investigation of electrocatalytic properties of modified nanocomposites in hydrogen oxidation reaction. Investigation of intercalation pathways of A2B6 quantum dots in synthesized germanium nanotubular structures. Stage 5:Establishing the interrelation between structural features of nanoheterostructures and electrophysical properties. Synthesis and investigation of nanotubular complex oxide structures based on vanadium compounds. The investigation of photo- and electrocatalytic properties of composites prepared and nanoheterostructures in photo- and electrochemical reactions of hydrogen generation and storage. The investigation of structural and optoelectronic properties of the prepared nanosystems.
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