排序方式: 共有44条查询结果,搜索用时 31 毫秒
1.
A. V. Chistyakov M. A. Gubanov V. Yu. Murzin P. A. Zharova M. V. Tsodikov V. V. Kriventsov A. E. Gekhman I. I. Moiseev 《Russian Chemical Bulletin》2014,63(1):88-93
The features of ethanol conversion into hydrocarbons C4-C12 in the presence of the novel catalyst Pd-Zn/γ-alumina and pilot zeolite system Pd-Zn/MFI/γ-alumina were studied (MFI is high-siliceous zeolite with ZSM-5 type structure). The structure of active sites changes noticeably in the course of preliminary activation and catalytic reaction. High selectivity and stability of the zeolite-containing Pd-Zn catalyst in alcohol conversion into hydrocarbon components of fuels is related to the stable composition of the alloy that forms clusters PdZn. At the same time, the alumina-based catalyst loses stability due to zinc diffusion from the alloy into γ-Al2O3 to form the spinel structure. 相似文献
2.
Tatiana Kuznetsova Vladislav Sadykov Lubsan Batuev Ella Moroz Elena Burgina Vladimir Rogov Vladimir Kriventsov Dmitrii Kochubey 《天然气化学杂志》2006,15(3):149-163
For dispersed ceria-zirconia-based solid solutions prepared via the polymerized complex method and annealed at 700℃, effects of bulk doping by Ca, Mn, Co, Bi or Nb cations and surface modification by Mn and Pt on their structural features, surface/bulk oxygen reactivity and catalytic activity in methane combustion are considered. With up to 20 mol% doping, a structural type of homogeneous solid solutions of anion-deficient fluorite with disordered anion vacancies is formed. Doping by transition metal cations or Pt increases the mobility and reactivity of the surface/bulk oxygen. A broad variation in specific rates of methane combustion for the studied systems was observed, suggesting structural sensitivity of this reaction. In general, there is no universal relationship between the oxygen mobility, the reactivity and the catalytic activity in methane combustion, which is explained by the factor of specific methane activation on surface active sites. For the Pt-promoted samples, Pt efficiency in methane activation depends on the Pt-support interaction, and the most favorable ones being mixed Pt/MnOx and Pt/NbOx clusters on the surface of the supports that exhibit high lattice oxygen mobilities. 相似文献
3.
R. G. Valeev A. N. Deev E. A. Romanov V. V. Kriventsov A. N. Beltyukov N. A. Mezentsev A. A. Eliseev K. S. Napolskii 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2010,4(4):645-648
A novel approach is presented for synthesis of ZnSe nanodot arrays by physical vapor deposition on porous aluminum oxide templates
with ordered channels. The structure of nanodots was studied by scanning electron microscopy and EXAFS spectroscopy. Data
were obtained for the sizes of nanodots in the array and local atomic structure parameters, i.e., the interatomic distances
and coordination numbers, in comparison with the data for the ZnSe film synthesized on a smooth surface of nonporous Al2O3. 相似文献
4.
N. Yu. Svechnikov V. G. Stankevich A. M. Lebedev K. A. Men’shikov B. N. Kolbasov V. V. Kriventsov 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2007,1(1):13-17
Homogeneous deuterated hydrocarbon films redeposited from a deuterium plasma discharge inside the T-10 tokamak vacuum chamber are studied using photoluminescence methods; EXAFS, EPR, and IR spectroscopies; and temperature measurements. The photoluminescence excitation spectra of sp 3-sp 2 nanostructures of tokamak films are compared with those of sp 2 nanostructures of C60 fullerite films. The effect of defect states on photoluminescence and its temperature quenching is discussed. It is concluded that the model of temperature luminescence quenching for homogeneous deuterated tokamak films is similar to that for amorphous a-C:H films. 相似文献
5.
V. P. Kolko E. M. Moroz V. V. Kriventsov D. A. Zyuzin 《Bulletin of the Russian Academy of Sciences: Physics》2007,71(5):695-698
Cerium dioxide samples of different dispersivity, obtained by different methods, have been investigated by X-ray diffraction (XRD) analysis, full-profile analysis of diffraction patterns, calculation of radial distribution function (RDF) of electron density, and extended X-ray absorption fine-structure (EXAFS) spectroscopy. According to the XRD data, the samples studied can be identified in the fluorite structure with conventional unit-cell parameters. However, the local structure of highly dispersed samples, determined by the RDF and EXAFS methods, changes: the coordination spheres for the Ce-O distances are represented by two distances. 相似文献
6.
7.
R. G. Valeev A. N. Deev F. Z. Gilmutdinov S. G. Bystrov O. I. Pivovarova É. A. Romanov V. V. Kriventsov M. R. Sharafutdinov A. A. Eliseev 《Journal of Structural Chemistry》2008,49(1):124-128
This paper presents the results of our study of the structural state and local atomic structure of zinc selenide films obtained by thermal evaporation in supervacuum at condensation temperatures of ?150°C, 0, and 150°C. Structure-sensitive methods such as X-ray diffraction, atomic force microscopy, and EXAFS spectroscopy were used. The parameters of the local atomic environment (interatomic distances, coordination numbers) of zinc and selenium atoms were obtained by Fourier transformation. 相似文献
8.
Tsodikov M. V. Slivinskii E. V. Yushchenko V. V. Kitaev L. E. Kriventsov V. V. Kochubei D. I. Teleshev A. T. 《Russian Chemical Bulletin》2000,49(12):2003-2006
The data of temperature-programmed desorption of ammonia from the surface of oxide systems and IR spectroscopy were used to demonstrate that the strength of the surface acid sites in titanium oxides prepared by the alkoxo method and modified by aluminum decreases with respect to that in nonmodified titanium oxide. Modification of titanium oxide with P3+ ions from ethriol phosphite almost completely suppresses the acid properties. Modified oxides are able to chemisorb water. XANES data suggest that modification of titanium oxide with phosphorus ions increases the electron density on the titanium atoms and, correspondingly, the basicity of the materials. 相似文献
9.
A. N. Beltyukov R. G. Valeev E. A. Romanov V. V. Kriventsov 《Bulletin of the Russian Academy of Sciences: Physics》2013,77(9):1137-1140
ZnS x Se(1 ? x) (x = 0.36, 0.68, and 0.73) films of various compositions are prepared by the thermal deposition of a mixture of zinc sulfide and zinc selenide powders in ultrahigh vacuum. It is shown that the produced films and the source materials are close in chemical composition. The crystal structure of the films is studied via X-ray diffraction. The local atomic environment of selenium and zinc atoms is studied by means of EXAFS spectroscopy. 相似文献
10.
V. V. Kriventsov E. P. Yakimchuk B. N. Novgorodov D. I. Kochubey I. L. Simakova D. A. Zyuzin D. G. Aksenov A. V. Chistyakov A. S. Fedotov K. V. Golubev V. Yu. Murzin M. V. Tsodikov 《Bulletin of the Russian Academy of Sciences: Physics》2013,77(9):1190-1194
Model low-percentage metal oxide palladium catalysts are prepared from acetate complexes of Pd and Mn to study the nature of the activity and the genesis of nanostructured membrane catalyst Pd-Mn systems. A comprehensive study of the prepared model precursor compounds; specific features of their metal components in gels and oxides; and the genesis of the active component, local structure, and charge state is performed by EXAFS and XANES. Possible versions of structural models for the stabilization of metals on oxide supports aare discussed. 相似文献