共查询到20条相似文献,搜索用时 15 毫秒
1.
P. P. Dik K. A. Nadeina M. O. Kazakov O. V. Klimov E. Yu. Gerasimov I. P. Prosvirin A. S. Noskov 《Catalysis in Industry》2018,10(1):29-40
Ni-Mo bimetallic catalysts are prepared by impregnating a carrier containing amorphous aluminosilicate (AAS) and aluminum oxide using a solution with Ni, Mo, and citric acid. The temperature of the catalysts ranges from 120 to 550°С. The physicochemical properties of the catalysts are studied via XPS, TEM, and HCNS analysis, and they are tested in hydrocracking of vacuum gasoil. The particles of the sulfide active component (NiMoS phase) are localized predominantly on surfaces of aluminum oxide, and only some are on surfaces of AAS. When the temperature of catalyst calcination is raised, the average number of the layers in particles of the NiMoS phase grows as well, due to the removal of citric acid. This indicates strengthening of the interaction between the sulfide active component and aluminum oxide. The content of Ni-Mo massive sulfide particles also grows along with the temperature of calcination. The morphological characteristics of the sulfide active component affect the activity of the catalysts in hydrodesulfurization and hydrodenitrogenation, but not in hydrocracking. The optimum heat treatment temperature for NiMo/AAS-Al2O3 catalysts prepared with citric acid is 120°C. Recommendations are given for the heat treatment of catalysts under industrial conditions. 相似文献
2.
3.
4.
Kamila Michalska Paweł Kowalik Wiesław Próchniak Tadeusz Borowiecki 《Catalysis Letters》2018,148(3):972-978
5.
The active sites for the hydrodenitrogenation of carbazole for a series of low loading nitrided Mo/Al2O3 catalysts have been investigated by a combination of CO adsorption, pyridine adsorption, temperature-programmed surface reaction
with hydrogen and fractal analysis. Accordingly, the active sites for different stages of reaction have been determined. It
is proposed that carbazole adsorbs on the edge of molybdenum nitride crystallites where it is hydrogenated to perhydrocarbazole
which desorbs, migrating to nitrogen deficient nitrogen planes where it undergoes C–N hydrogenolysis. 相似文献
6.
Synthetic spinels of the system MgO-Cr2O3-Al2O3-Fe2O3 are considered and the desirability of organizing their production for the refractory industry is demonstrated.
Translated from Novye Ogneupory, No. 6, pp. 32–35, June 2008. 相似文献
7.
Abstract
Ce X Zr1−X O2 catalysts with different cerium content (X) (X = 0, 0.2, 0.4, 0.5, 0.6, 0.8, and 1.0) were prepared by a sol–gel method for use in the direct synthesis of dimethyl carbonate from methanol and carbon dioxide. Among these catalysts, Ce0.6Zr0.4O2 was found to show the best catalytic performance. In order to enhance the acidity and basicity of Ce0.6Zr0.4O2 catalyst, Ga2O3 was supported on Ce0.6Zr0.4O2 (XGa2O3/Ce0.6Zr0.4O2 (X = 1, 5, 10, and 15)) by an incipient wetness impregnation method with a variation of Ga2O3 content (X, wt%). Effect of acidity and basicity of Ga2O3/Ce0.6Zr0.4O2 on the catalytic performance in the direct synthesis of dimethyl carbonate was investigated using NH3-TPD and CO2-TPD experiments. Experimental results revealed that both acidity and basicity of the catalysts played a key role in determining the catalytic performance in the direct synthesis of dimethyl carbonate from methanol and carbon dioxide. Large acidity and basicity of the catalyst facilitated the formation of dimethyl carbonate. The amount of dimethyl carbonate produced over XGa2O3/Ce0.6Zr0.4O2 catalysts increased with increasing both acidity and basicity of the catalysts. Among the catalysts tested, 5Ga2O3/Ce0.6Zr0.4O2, which retained the largest acidity and basicity, showed the best catalytic performance in the direct synthesis of dimethyl carbonate from methanol and carbon dioxide. 相似文献8.
C. Sepulveda R. Garcia N. Escalona D. Laurenti L. Massin M. Vrinat 《Catalysis Letters》2011,141(7):987-995
Abstract
Rhenium sulfide based catalysts were prepared by the incipient wetness impregnation method over alumina and silica supports and evaluated for 4,6-dimethyldibenzothiophene hydrodesulfurization in a high-pressure stirred-tank reactor. The catalyst prepared over silica was about six times more active for hydrodesulfurization than the corresponding catalyst prepared over alumina and a NiMo/Al2O3 industrial reference catalyst. This surprising and positive SiO2 support effect was explained by a metallic character of the supported sulfide, which was demonstrated using a kinetic approach of competitive hydrogenations and by XPS characterization. 相似文献9.
O. V. Belyaeva T. A. Krasnova S. A. Semenova O. S. Gladkova 《Solid Fuel Chemistry》2011,45(6):418-421
The results of the modification of AG-OV-1 activated carbon under various conditions (by atmospheric oxygen at elevated temperatures
and by hydrogen peroxide or ozone) are given. The effect of the used modifier on changes in the porosity, surface state, and
adsorption capacity of activated carbon is evaluated. 相似文献
10.
Jeong Gil Seo Min Hye Youn Kyung Min Cho Sunyoung Park Sang Hee Lee Joohyung Lee In Kyu Song 《Korean Journal of Chemical Engineering》2008,25(1):41-45
An Al2O3-ZrO2 xerogel (AZ-SG) was prepared by a sol-gel method for use as a support for a nickel catalyst. The Ni/AZ-SG catalyst was then
prepared by an impregnation method, and was applied to hydrogen production by steam reforming of LNG. A nickel catalyst supported
on commercial alumina (A-C) was also prepared (Ni/A-C) for comparison. The hydroxyl-rich surface of the AZ-SG support increased
the dispersion of nickel species on the support during the calcination step. The formation of a surface nickel aluminate-like
phase in the Ni/AZ-SG catalyst greatly enhanced the reducibility of the Ni/AZ-SG catalyst. The ZrO2 in the AZ-SG support increased the adsorption of steam onto the support and the subsequent spillover of steam from the support
to the active nickel sites in the Ni/AZ-SG catalyst. Both the high surface area and the well-developed mesoporosity of the
Ni/AZ-SG catalyst improved the gasification of adsorbed surface hydrocarbons in the reaction. In the steam reforming of LNG,
the Ni/AZ-SG catalyst showed a better catalytic performance than the Ni/A-C catalyst. Moreover, the Ni/AZ-SG catalyst showed
strong resistance toward catalyst deactivation. 相似文献
11.
12.
V. F. Popova E. A. Tugova A. S. Isaeva I. A. Zvereva V. V. Gusarov 《Glass Physics and Chemistry》2007,33(5):498-501
The phase formation is investigated and the phase diagram of the Ho2O3-SrAl2O4 system is constructed. A ternary compound, namely, Ho2SrAl2O7, is revealed. It is established that this compound undergoes incongruent melting. 相似文献
13.
I. A. Zvereva V. F. Popova E. A. Tugova N. S. Pylkina V. V. Gusarov 《Glass Physics and Chemistry》2005,31(6):808-811
The phase equilibria are investigated and the phase diagram is constructed for the Gd2O3-SrAl2O4 pseudobinary join of the Gd2O3-SrO-Al2O3 ternary oxide system. One ternary compound, namely, Gd2SrAl2O7, is revealed in the Gd2O3-SrAl2O4 join. It is found that this compound undergoes congruent melting. 相似文献
14.
15.
16.
17.
V. A. Sokolov T. Ya. Malysheva M. D. Gasparyan 《Refractories and Industrial Ceramics》2008,49(2):146-148
Details are given of the synthesis and testing of flux-cast refractory materials in the alumina-rich region of the Al2O3-MgO-B2O3 system; XRD and petrography indicate that the main structure-forming phases are corundum and magnesian spinel. In subordinate
amounts there are the boroaluminate 9Al2O3·2B2O3 and the previously unknown compound 4Al2O3·MgO·2B2O3, whose composition has been established by microprobe analysis. Corrosion tests showed that three-component systems containing
magnesium and boron oxides at levels of 5–10% do not increase the corrosion resistance of refractories in molten sodium-calcium-silicate
glass and electrovacuum borosilicate glass.
__________
Translated from Novye Ogneupory, No. 3, pp. 161–163, March, 2008. 相似文献
18.
Structure and crystalline behavior of the ternary system ZnO-B2O3-P2O5 glasses were investigated by means of X-ray diffraction (XRD) and infrared Raman spectra. The research showed that number
of the planar [BO3] units increases with the increase of B2O3 content. When the B2O3 content is above ≥10 mol %, the relative content of planar [BO3] units increases rapidly and causes weakening of the glass structure and decrease in the chemical stability. In the crystallized
glasses the predominant crystal phase Zn2P2O7 decreases with the increase of B2O3 content, while the crystal phase BPO4 increases with it, which cause the declining of chemical stability and the decrease of thermal coefficients of expansion. 相似文献
19.
G. J. Wang L. J. Fu B. Wang N. H. Zhao Y. P. Wu R. Holze 《Journal of Applied Electrochemistry》2008,38(4):579-581
20.
The Sb2O3 doping lead-free glass in Bi2O3-B2O3-BaO ternary system were prepared in the composition of several different subsystem, and the glass powder was produced through
the process of water quenching. Glass transition temperatures (T
g
), glass soften temperatures(T
s
), the volume resistivity (ρ) in the temperature range of 80–200°C, and linear thermal coefficients of expansion in the temperatures
range of 25–300°C (α25–300) were measured for subsystems along with the different ratio of Bi2O3, B2O3 and BaO. For these subsystems, T
g
ranged from 458 to 481°C, and T
s
ranged from 490 to 512°C, both decreasing with the increasing of Bi2O3/B2O3 ratio, and increasing with the increasing of BaO/B2O3 ratio. The measured α25–300 ranged from 65.3 to 76.3 × 10−7 K−1, with values increasing with increasing Bi2O3/B2O3 and BaO/B2O3 ratio. The volume resistivity remains at a high standards, which may caused by it’s non-alkali composition, and it fluctuated
from 1013 to 1011 Ω cm with the temperature varied from 80–200°C. The structure of Bi2O3-B2O3-BaO ternary leadfree glass system was mearsured by FT-IR. The IR studies indicate that these glasses are made up of [BiO6], [BO3], and [BO4] basic structural units, and it appears that Ba2+ acts as a glass-modifier in this ternary system, but the Bi3+ has entered the glass network when it is in relative high content so as to change the α25–300, T
s
and T
g
. 相似文献