Vernadskii Institute of General and Inorganic Chemistry

Kiev, Ukraine

Vernadskii Institute of General and Inorganic Chemistry

Kiev, Ukraine

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Voloshin Y.Z.,RAS Nesmeyanov Institute of Organoelement Compounds | Dolganov A.V.,RAS Nesmeyanov Institute of Organoelement Compounds | Varzatskii O.A.,Vernadskii Institute of General and Inorganic Chemistry | Bubnov Y.N.,RAS Nesmeyanov Institute of Organoelement Compounds
Chemical Communications | Year: 2011

Specially designed hexachlorine-containing cobalt(ii) tris-dioximate clathrochelates were found to efficiently electrocatalyze the production of molecular hydrogen from H+ ions without the overpotential of this process. © 2011 The Royal Society of Chemistry.


Malyshev V.V.,Vernadskii Institute of General and Inorganic Chemistry | Gab A.I.,Ukraine Open International University for Human Development
Protection of Metals and Physical Chemistry of Surfaces | Year: 2012

Physicochemical (thickness, hardness, adhesion to support, wear resistance, abrasive resistance, porosity, corrosion stability) properties of high-temperature galvanic coatings of molybdenum, tungsten, and carbides thereof are studied. © Pleiades Publishing, Ltd., 2012.


Bersirova O.L.,Vernadskii Institute of General and Inorganic Chemistry | Kublanovskii V.S.,Vernadskii Institute of General and Inorganic Chemistry
Materials Science | Year: 2012

For polycrystalline silver coatings electrodeposited from electrolytes based on different Ag(I) coordination compounds such as [Ag(CN) 2]-, [Ag(CN)3]2-, [Ag(SCN) 4]3-, [Ag(CN)2(SCN)2]3-, and [Ag(SO3)2]3- at current densities of 2.5 to 75 mA×cm-2, we have established a relationship between the corrosion parameters of these deposits determined by the methods of electrochemical impedance spectroscopy and voltammetry and their crystalline roughness (uniformity at the nanolevel). We have also established that, with decrease in the surface roughness of an electrolytic silver deposit (R a ∼ 40-80 nm), the corrosion resistance increases. In this case, as the surface roughness increases by 20 nm, the corrosion resistance is halved, and the resistance to a corrosive medium decreases noticeably, though the deposit is uniformly distributed over the thickness on the microprofile. For silver coatings with the same true surface area, the larger the mean roughness R a, the larger the corrosion rate, independently of the texture of the deposit and deposition conditions. © 2012 Springer Science+Business Media New York.


Omel'chuk A.A.,Vernadskii Institute of General and Inorganic Chemistry
Russian Journal of Electrochemistry | Year: 2010

Results of studying how the composition of metal and salt phases depends on electrorefining conditions and duration are shown. It is demonstrated that the existing designs of electrolyzers with liquid electrodes fail to provide the uniform distribution of current density over electrode surfaces thus favoring the complicated distribution of molten electrolyte components throughout the electrolyzer volume. This makes it impossible to assess a priori the content of impurities in the refined metal and in the fused electrolyte. An empiric method is proposed for assessing the time of electrolysis up to the production of a metal of desired purity as well as the concept of an electrolyzer that rules out the nonuniform current density distribution. To minimize the transfer of impurity metals from anode to cathode, the use of a porous auxiliary electrode is proposed and the conditions for co-discharge of cations on it are determined. © Pleiades Publishing, Ltd., 2010.


Kublanovsky V.S.,Vernadskii Institute of General and Inorganic Chemistry | Nikitenko V.N.,Vernadskii Institute of General and Inorganic Chemistry
Journal of Electroanalytical Chemistry | Year: 2013

The kinetic parameters of palladium(II) electroreduction from a glycinate electrolyte and electrode reaction orders for ligand and hydrogen ions have been determined. The composition of electrochemically active complexes (EACs) which are directly involved in the electron-transfer reaction has been determined. It has been shown that the limiting current is of diffusion nature. Depending on electrolyte composition and pH, the glycinate complexes [PdGly]+, [Pd(Gly)3]- and [Pd(Gly)4]2- take part in the electron-transfer reaction. Diglycinate complexes [Pd(Gly) 2] are electrochemically inactive (EIC's). A probable mechanism of palladium(II) reduction from glycinate electrolyte is proposed. © 2013 Elsevier B.V.All rights reserved.


Devyatkin S.V.,Vernadskii Institute of General and Inorganic Chemistry
ECS Transactions | Year: 2014

In this work, the interaction of Si, SiC and TiC with a Na2CO3- K2CO3 melt at 7500° on Ar atmosphere and in air was investigated. The optimal process for the fabrication of carbon fibers or nanotubes is interaction between silicon carbide and carbonate melts. It has been show that the modification of carbon materials depends on SiC powder fineness. Copyright © 2014 by The Electrochemical Society. All rights reserved.


Belous A.G.,Vernadskii Institute of General and Inorganic Chemistry
International Conference on Oxide Materials for Electronic Engineering - Fabrication, Properties and Applications, OMEE 2014 - Book of Conference Proceedings | Year: 2014

Three types of ferromagnetic nanostructures based on barium hexaferrite (BaFe12O19), lanthanum-strontium manganites with perovskite structure (La1-xSrxMnO3) and materials with spinel structure (AFe2O4, A = Ni, Zn, Co, Mn, Fe) have been synthesized by precipitation from aqueous and nonaqueous solutions, by the sol-gel method and from microemulsions. Magnetic properties of the synthesized nanoparticles and films have been investigated. It was shown that the obtained nanoparticles exhibit superparamagnetic properties. It has been found that the synthesized nanoparticles have promise in hyperthermia of cancer cells. It has been shown that the films based on barium hexaferrite can have promise in the creation of nonlinear resonant microwave elements on the basis of high-Q dielectric resonators and ferromagnetic film. © 2014 IEEE.


Kublanovsky V.S.,Vernadskii Institute of General and Inorganic Chemistry | Nikitenko V.N.,Vernadskii Institute of General and Inorganic Chemistry
Electrochimica Acta | Year: 2011

The kinetics of trans-cis-isomerization of palladium(II) diglycinate complexes have been studied by the spectrophotometric and potentiometric methods. The reaction of transition of trans-[Pd(Gly)2] to cis-[Pd(Gly)2] is described by a first-order equation. The half-life of the trans-isomer [Pd(Gly)2] and the rate constant of the reaction of its transition to cis-isomeric structure have been determined. A mechanism of transformation of trans-[Pd(Gly)2] into cis-[Pd(Gly)2] is proposed. The spectral characteristics and electrochemical parameters of palladium(II) trans- and cis-diglycinate complexes have been determined. The mechanism of electroreduction of palladium(II) from glycinate electrolyte containing no excess free ligand has been elucidated. © 2010 Elsevier Ltd.


Plutenko T.,Vernadskii Institute of General and Inorganic Chemistry | V'yunov O.,Vernadskii Institute of General and Inorganic Chemistry
Solid State Phenomena | Year: 2013

Ceramic samples of (1-x)BaTiO3-xNa0.5Bi0.5TiO3 system were prepared by sintering in reducing atmosphere of N2/H2 and were subsequently reoxidized in air. The influence of reoxidation temperature firing on the PTCR effect of (1-x)BaTiO3-xNa0.5Bi0.5TiO3 ceramics was investigated. The effect of Na0.5Bi0.5TiO3 concentration on resistivity and microstructure of the reoxidized samples was investigated by means of complex impedance spectroscopy and scanning electron microscopy. It has been found that the grain size decreases with the increase in Na0.5Bi0.5TiO3 content. The values of minimum ρmin and maximum ρmax resistivities of the samples were observed to increase with the increase in reoxidation temperature in the 600 - 1000°C temperature range. It was shown that with increasing in reoxidation temperature of (1-x)BaTiO3-xNa0.5Bi0.5TiO3 solid solutions, potential barrier at grain boundaries increases. © (2013) Trans Tech Publications, Switzerland.


Dzyazko Y.S.,Vernadskii Institute of General and Inorganic Chemistry | Ponomaryova L.N.,Vernadskii Institute of General and Inorganic Chemistry | Rozhdestvenskaya L.M.,Vernadskii Institute of General and Inorganic Chemistry | Vasilyuk S.L.,Vernadskii Institute of General and Inorganic Chemistry | Belyakov V.N.,Vernadskii Institute of General and Inorganic Chemistry
Desalination | Year: 2014

Organic-inorganic ion-exchangers have been obtained by modification of gel-like flexible resin with zirconium hydrophosphate, which form both single and aggregated nanoparticles in the polymer matrix. Insertion of the inorganic constituent into the resin up to 40 mass % was found to increase electrical conductivity of the resin from 0.2 to 0.7Ω-1m-1. Total ion-exchange capacity also increases from 600 to 1800molm-3. The organic-inorganic ion-exchanger with the highest amount of the inorganic constituent was used for electrodeionization processes to remove Ni2+ from low-concentrated solutions containing also hardness ions and organic substances. The "once-through" processes have been developed based on ion transport investigation under variation of the initial pH, concentration, and flow velocity of the solution being purified. Residual Ni2+ content in the solution was 0.7-0.9ppm, the energy consumptions have been estimated 0.4-0.7kWh per 1m3. The organic-inorganic ion-exchanger was found to demonstrate stability against fouling with organic substances as opposed to the unmodified resin. © 2013 Elsevier B.V.

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