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1.
V. I. Zheivot T. A. Nikoro V. N. Krivoruchko L. I. Panina L. G. Pinaeva L. A. Isupova 《Journal of Analytical Chemistry》2007,62(12):1170-1175
Peculiarities of the determination of nitrogen oxides and ammonia in the reaction products of ammonia oxidation are studied by gas chromatography. Particular attention was paid to the sampling problem. It is shown that in the course of the transportation of samples containing nitrogen(II) oxide and oxygen, the oxidation of nitrogen(II) oxide to nitrogen(IV) oxide takes place in the vapor phase. The conditions were found for suppressing or even eliminating the gas-phase reaction of NO oxidation to NO2. A procedure for the gas-chromatographic analysis of the reaction products in the catalytic oxidation of ammonia is proposed using several samples and packed columns, including the determination of NO with respect to NO2 formed in the gas-phase oxidation of NO. 相似文献
2.
L.A. Isupova I.S. Yakovleva I.I. Gainutdinov Yu.T. Pavlyukhin V.A. Sadykov 《Reaction Kinetics and Catalysis Letters》2004,81(2):373-382
The phase composition and microstructure of samples of the La1-xCaxFeO3-y system prepared via a ceramic route were characterized by M?ssbauer spectroscopy. In all cases, iron was found in the 3+ state. The ordering
of anion vacancies in the samples with the composition in the range of 0.8 > x ≥ 0.4, which corresponds to a microheterogeneous
solid solution, generates new distorted octahedral and fivefold/tetrahedral sites revealed by two typical sextets. The disordering
of this solid solution and small (10-100 ?) sizes of domains with a perovskite, braunmillerite or Grenier phase structure
caused the appearance of a superparamagnetic doublet, which grows with the Ca content up to x = 0.8 but disappears in the
sample of pure braunmillerite. The appearance of Fe cations in a distorted coordination correlates with the increased activity
of the samples with a microheterogeneous structure in the CO catalytic oxidation and with their reducibility by H2.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
3.
L. A. Isupova V. Yu. Aleksandrov V. V. Popovskii V. A. Balashov A. A. Davydov A. A. Budneva N. N. Kryukova 《Reaction Kinetics and Catalysis Letters》1986,31(1):195-202
Mechano-chemical activation of copper oxide powders leads to structural disordering of the near-surface layers of particles and, thus, to considerable variations in the catalytic properties of copper oxide.
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4.
L. A. Isupova V. A. Sadykov V. P. Ivanov A. A. Rar S. V. Tsybulya M. P. Andrianova V. N. Kolomilchuk A. N. Petrov O. F. Kononchuk 《Reaction Kinetics and Catalysis Letters》1994,53(1):223-229
Catalytic properties of strontium-substituted lanthanum cobaltites La1–xSrxCoO3 in the reaction of CO oxidation were compared with the data about chemical composition of the surface and bulk defect structure. It was found that (1) the initial catalytic activity correlates with the cobalt concentration on the surface; (2) surface composition differs from the bulk one; (3) the steady-state activity is proportional to the density of bulk extended defects. Under our experimental conditions no role of point defects was noted. 相似文献
5.
E. V. Ovchinnikova L. A. Isupova I. G. Danilova V. V. Danilevich B. A. Chumachenko 《Russian Journal of Applied Chemistry》2016,89(5):683-689
Possibility of using products formed in centrifugal thermal activation of hydrargillite to obtain alumina catalysts washed to remove admixtures of alkali metals was considered. A comparison of the physicochemical and catalytic properties of the samples demonstrated that washing with water is more favorable than that with nitric acid; the catalytic activity and acid-base properties of the catalyst surface are determined not only by the content of Na, but also by the whole set of catalyst preparation conditions. The most active of the samples obtained in the study has acidity close to that of industrial aluminum oxide produced by the reprecipitation method, but surpasses it in activity: at 370°C, the total yield of ethylene and diethyl ether reaches a value of 88.8 mol %, which is 4% higher than that for the reference sample. 相似文献
6.
A. N. Nadeev S. V. Tsybulya E. Yu. Gerasimov N. A. Kulikovskaya L. A. Isupova 《Journal of Structural Chemistry》2010,51(5):891-897
A synthesis method with the use of polymer-salt compositions (calcination temperature 800°C) provides the preparation of various
solid solutions of a La1−x
Ca
x
FeO3−δ series in the 0≤ x≤ 0.7 range, which belong to the perovskite structure type. A morphotropic phase transition occurs from the orthorhombic perovskite
modification (0≤ x ≤ 0.4) to the cubic one (0.5 ≤ x≤ 0.7). A growing number of microdistortions in the perovskite structure and the formation of a microblock structure in the
morphotropic phase transition region are observed with increasing degree of calcium substitution for lanthanum. Calcination
of solid solutions with x = 0.6 and 0.7 at temperatures above 1000°C in the air or under conditions of reduced oxygen partial pressure (laboratory
vacuum of 10−3 Torr) results in the formation of a nanostructured state with coherently grown blocks of perovskite and Grenier phase, which
is due to irreversible oxygen loss. 相似文献
7.
Sutormina E. F. Isupova L. A. Kulikovskaya N. A. Plyasova L. M. Rudina N. A. 《Kinetics and Catalysis》2010,51(1):131-134
The effects of iron oxide (10%), bismuth oxide (2.2%), and vanadium oxide (1.6%) admixtures on the physicochemical properties
of cordierite ceramics are reported, including the phase composition, surface features, porous structure, and activity in
ammonia oxidation. The formation of the cordierite phase is favored by introducing the oxide modifiers, by raising the heat
treatment temperature, and by extending the heating time. The introduction of V2O5 affords well-crystallized cordierite with a small specific surface area and a large proportion of macropores. The oxide modifiers
markedly enhance the ammonia oxidation activity and nitrogen oxide selectivity of the cordierite ceramics. 相似文献
8.
The transport properties of a circular billiard with attached channels, which is an open system, have been studied in the
presence of the Dresselhaus and Rashba spin-orbit interactions. It has been shown that this interaction leads to the appearance
of additional Fano resonances in the energy dependence of the conductance, the width of which is proportional to the fourth
power of the spin-orbit coupling constant. 相似文献
9.
S. I. Reshetnikov A. V. Livanova E. P. Meshcheryakov I. A. Kurzina L. A. Isupova 《Russian Journal of Applied Chemistry》2017,90(11):1760-1765
Fundamental dynamic (kinetic) aspects of the process in which water vapor interacts with the surface of drying agents that are synthesized on the basis of low-temperature modification of aluminum oxide produced from a pseudoboehmite-containing hydroxide and are modified (doped) with alkali atoms (K, Na). It is shown that the kinetics of adsorption on the samples under study, formed from the fine fraction (0.5–1.0 mm) of aluminum oxide adsorbents, can be described with the Glueckauf equation, which rather well describes the dynamics of water vapor absorption in the course of time. The equation parameters were determined: adsorption rate constants and the equilibrium adsorption capacities (a*). It was found that the alkaline modification of the surface of aluminum oxide adsorbents results in that a* increases (by ~40%) as compared with the unmodified drying agent. A correlation is observed between the equilibrium adsorption capacity of the samples under study and the acid-base properties of the surface. 相似文献
10.
D. V. Ivanov L. G. Pinaeva E. M. Sadovskaya L. A. Isupova 《Kinetics and Catalysis》2011,52(3):401-408
Radically different dependences of the activity of La1 − x
Sr
x
MnO3 (x = 0−0.5) perovskites in methane oxidation on the degree of substitution of strontium for lanthanum are observed for low and
high temperatures. Unsubstituted LaMnO3 exhibits the highest activity in the temperature range from 300 to 500°C, while the sample with the maximum degree of substitution
(La0.5Sr0.5MnO3) shows the highest activity at higher temperatures of 700–900°C. In the low temperature region, the activity of La1t - x
Sr
x
MnO3 is determined by the amount of weakly bound (overstoichiometric) oxygen, which is formed in cation-deficient lattices and
is characterized by a thermal desorption peak with T
max = 705°C. At higher temperatures (800–900°C), the strongly bound oxygen of the catalyst lattice is involved in the formation
of the reaction products under both unsteady- and steady-state conditions. As a consequence, the catalytic activity in methane
oxidation correlates with the apparent rate constant of oxygen diffusion in the oxide bulk. 相似文献