Search results for: Y. V. Zubavichus

Items from 1 to 11 out of 11 results

article

Structure and Chemistry of Cu–Fe–Al Nanocomposite Catalysts for CO Oxidation

A. V. Fedorov, A. M. Tsapina, O. A. Bulavchenko, A. A. Saraev, more

Catalysis Letters > 2018 > 148 > 12 > 3715-3722

High-active Fe–Al and Cu–Fe–Al nanocomposite catalysts were synthesized by fusion of aluminium, iron, and copper salts and then tested in the oxidation of CO. It was found that the activity of Fe–Al catalysts depends on the Fe concentration and the maximum is achieved when the Fe₂O₃ content is approximately 82 wt%. The addition of Cu leads to a significant increase in activity. Using adsorption techniques,...

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Structure of Nd₅Mo₃O_{16 + δ} Single Crystals Doped with Tungsten

A. M. Antipin, N. I. Sorokina, O. A. Alekseeva, Y. V. Zubavichus, more

Crystallography Reports > 2018 > 63 > 3 > 339-343

The structure of tungsten-doped Nd₅Mo₃O_{16 + δ} single crystals has been investigated by X-ray diffraction analysis, energy-dispersive X-ray spectroscopy (EDXS) microanalysis, and extended X-ray absorption fine-structure (EXAFS) spectroscopy. Tungsten atom, which partially replaces molybdenum atoms in the structure, is found to be located close (at a distance of 0.57 Å) to the Mo atom site. The interstitial...

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Revealing the Influence of Silver in Ni–Ag Catalysts on the Selectivity of Higher Olefin Synthesis from Stearic Acid

V. Ya. Danyushevsky, V. Yu. Murzin, P. S. Kuznetsov, R. S. Shamsiev, more

Russian Journal of Physical Chemistry A > 2018 > 92 > 1 > 57-65

Results on the conversion of stearic acid to olefins over Ni–Ag/γ-Al₂O₃ catalysts are presented. XANES and EXAFS experiments in situ and DFT calculations were applied to reveal the structure of active sites therein. It is shown that the introduction of Ag to Ni catalysts leads to an increase in the olefin yield. After a reduction in hydrogen (350°C, 3 h) alumina-supported nanoparticles of nickel sulfides...

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Cluster-Type Structure of Amorphous Smooth Hydrocarbon CD_x Films (x ~ 0.5) from T-10 Tokamak

N. Yu. Svechnikov, V. G. Stankevich, B. N. Kolbasov, Y. V. Zubavichus, more

Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques > 2017 > 11 > 6 > 1208-1215

Structure of smooth hydrocarbon CD_x films with a high deuterium ratio x ~ 0.5 redeposited from T-10 tokamak D-plasma discharges (NRC Kurchatov Institute, Moscow) has been studied. For the first time, small and wide angle X-ray scattering technique using synchrotron radiation and neutron diffraction have been employed. A fractal structure of CD_x films is found to consist of mass-fractals with rough...

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Crystal and local atomic structure of MgFeBO₄, Mg_0.5Co_0.5FeBO₄ and CoFeBO₄: Effects of Co substitution

N. V. Kazak, M. S. Platunov, Yu. V. Knyazev, N. B. Ivanova, more

physica status solidi (b) > 252 > 10 > 2245 - 2258

Single‐crystalline MgFeBO_4, Mg_0.5Co_0.5FeBO₄, and CoFeBO₄ have been grown by the flux method. The samples have been characterized by X‐ray spectral analysis, X‐ray diffraction, and X‐ray absorption spectroscopy. The X‐ray absorption near‐edge structure (XANES) and extended X‐ray absorption fine structure (EXAFS) spectra have been measured at the Fe and Co K‐edges over a wide temperature range (6.5–300...

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Local Electronic and Crystal Structure of Magnetic RCo ₂ As ₂ (R = La, Ce, Pr, Eu)

A. P. Menushenkov, A. A. Yaroslavtsev, A. Y. Geondzhian, R. V. Chernikov, more

Journal of Superconductivity and Novel Magnetism > 2015 > 28 > 3 > 995-997

The experimental X-ray absorption data on the recently prepared magnetic arsenides RCo ₂ As ₂ (R = rare earth) are provided. The oxidation state of rare-earth ions is explored by means of the X-ray absorption near edge structure (XANES) spectroscopy. Ce and Eu exhibit the intermediate valence state. The rare-earth valence instability sensitive to external perturbations...

article

Supercoiling as a physical mechanism providing a macroscopic scale in supramolecular strings

S. V. Stovbun, A. A. Skoblin, Y. A. Litvin, A. A. Kirsankin, more

Russian Journal of Physical Chemistry B > 2014 > 8 > 6 > 801-806

Quantum-chemical calculations revealed that chiral and achiral TFAAA molecules combine to form dimers with comparable binding energies. It was experimentally established that solutions of both chiral and achiral TFAAAs contain anisometric structures with a diameter of d ≪ 1 nm and a length of L ∼ 7 nm. It was concluded that the qualitative difference in the pattern of the supramolecular structure...

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X-ray diffraction and EXAFS analysis of materials for lithium-based rechargeable batteries

M. D. Sharkov, M. E. Boiko, A. V. Bobyl, E. M. Ershenko, more

Crystallography Reports > 2013 > 58 > 7 > 993-997

Lithium iron phosphate LiFePO₄ (triphylite) and lithium titanate Li₄Ti₅O₁₂ are used as components of a number of active materials in modern rechargeable batteries. Samples of these materials are studied by X-ray diffraction and extended X-ray absorption fine structure (EXAFS) spectroscopy. Hypotheses about the phase composition of the analyzed samples are formulated.

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Small-angle scattering of synchrotron radiation investigations of nanostructured alumina membranes synthesized by sol–gel method

E. F. Krivoshapkina, A. P. Petrakov, P. V. Krivoshapkin, Y. V. Zubavichus, more

Journal of Sol-Gel Science and Technology > 2013 > 68 > 3 > 488-494

Alumina asymmetric ceramic membranes were prepared by sol–gel method. Research on structure of alumina membrane active layer is conducted by methods of physical nitrogen adsorption and small-angle scattering of synchrotron radiation, the obtained data confirms and supplements each other. Surface area for the studied material varies from 255 to 264 m²/g, average pore diameter varies from 5.3 nm to...

article

Magnetic nanocomposites based on hypercrosslinked polystyrenes

A. V. Pastukhov, V. A. Davankov, V. V. Volkov, K. A. Dembo, more

Bulletin of the Russian Academy of Sciences: Physics > 2009 > 73 > 4 > 471-473

Magnetic sorbents (composites with inclusions of iron oxide nanoparticles in a polymer matrix), which can be used to remove toxic compounds by the magnetic separation method, have been developed on the basis of hypercrosslinked polystyrenes. Composites based on gel-type hypercrosslinked polystyrenes contain nanoparticles with a radius of ∼3 nm, while biporous hypercrosslinked polystyrenes (with micro-...