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1.
Gold catalysts with loadings ranging from 0.5 to 7.0 wt% on a ZnO/Al2O3 support were prepared by the deposition–precipitation method (Au/ZnO/Al2O3) with ammonium bicarbonate as the precipitation agent and were evaluated for performance in CO oxidation. These catalysts
were characterized by inductively coupled plasma-atom emission spectrometry, temperature programmed reduction, and scanning
transmission electron microscopy. The catalytic activity for CO oxidation was measured using a flow reactor under atmospheric
pressure. Catalytic activity was found to be strongly dependent on the reduction property of oxygen adsorbed on the gold surface,
which related to gold particle size. Higher catalytic activity was found when the gold particles had an average diameter of
3–5 nm; in this range, gold catalysts were more active than the Pt/ZnO/Al2O3 catalyst in CO oxidation. Au/ZnO/Al2O3 catalyst with small amount of ZnO is more active than Au/Al2O3 catalyst due to higher dispersion of gold particles. 相似文献
2.
M. S. Nikulshina A. V. Mozhaev P. P. Minaev M. Fournier C. Lancelot P. Blanchard E. Payen C. Lamonier P. A. Nikulshin 《Russian Journal of Applied Chemistry》2017,90(7):1122-1129
Trimetallic NiMoW/Al2O3 catalyst was prepared using mixed H4SiMo3W9O40 heteropoly acid of Keggin structure and nickel citrate. Bimetallic NiMo/Al2O3 and NiW/Al2O3 catalysts based on H4SiMo12O40 and H4SiW12O40, respectively, were synthesized as reference samples. The use of mixed H4SiMo3W9O40 heteropoly acid as an oxide precursor allows the tungsten sulfidation degree and the degree of promotion of active phase particles to be increased. The hydrodesulfurization activity is enhanced as compared to NiW/Al2O3 catalyst. The synergistic enhancement of the activity of the NiMo3W9/Al2O3 catalyst relative to the bimetallic analogs is probably caused by formation of new mixed promoted active sites for direct desulfurization. 相似文献
3.
Sheng-Li Chen Haitao Wang Guimei Yuan Zhiqing Wang Zhi Cai 《Transition Metal Chemistry》2011,36(4):441-445
Macro-/mesoporous Al2O3 supports were prepared by using monodisperse polystyrene (PS) microspheres as a template. The pore volume and BET surface
area of the Al2O3 supports increased considerably with increasing amounts of the PS microspheres; further investigation showed that PS template
only increased the volume of macro-pores but did not change the volume of meso-pores or micro-pores. Macro-/mesoporous Re2O7/Al2O3 metathesis catalysts were prepared through loading Re2O7 onto the as-prepared macro-/mesoporous Al2O3 supports, and their catalytic performance was tested in a fixed-bed tubular reactor using the metathesis of normal butylenes
as a probe reaction. The results showed that the prepared macro-/mesoporous Re2O7/Al2O3 catalyst had high activity with consistent selectivity; propylene and pentene accounted for more than 90 wt% of the metathesis
products, while the amount of ethylene plus hexane was less than 10 wt%, the majority of which was hexane. These Re2O7/Al2O3 catalysts had not only higher activity, but also longer working life span and higher tolerance to carbon residues than conventional
Re2O7/Al2O3 catalysts. 相似文献
4.
N. M. Maximov N. N. Tomina P. S. Solmanov A. A. Pimerzin 《Russian Journal of Applied Chemistry》2017,90(4):574-581
Со-Мо/Al2O3 and Ni-W/Al2O3 catalysts were tested in hydrotreating of light cycle oil from catalytic cracking, of the straight-run gasoil, and of their mixture under typical hydrotreating conditions used in industry. The catalysts prepared using PMo12 and PW12 heteropoly acids exhibit high catalytic activity. The Со-Мо/Al2O3 catalyst is more active in hydrodesulfurization and hydrogenation of olefin and diene hydrocarbons, whereas the Ni-W/Al2O3 catalysts are more active in hydrogenation of mono- and polycyclic aromatic hydrocarbons. Comparison of the quality characteristics of the hydrogenizates obtained with the requirements of the technical regulations shows that the required levels of the sulfur content and cetane number of the hydrogenizates at practically accessible process parameters can be reached for mixtures of the straight-run gasoil and light cycle oil from catalytic cracking with high content of the latter component only when the process with the Со-Мо/Al2O3 system and Ni-W/Al2O3 catalysts is performed in two steps. 相似文献
5.
P. A. Chernavskii Chu Vei A. Yu. Khodakov G. V. Pankina N. V. Peskov 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2008,82(6):951-955
The mean size of Co particles and the variance of distribution were shown to increase as the temperature of calcining grew. The size was maximum at a 400°C temperature of calcining and decreased somewhat at 500°C. The mean Co particle size decreased in the presence of Pt, and the particle-size distribution narrowed. A decrease in the mean particle size in the Co/Pt/Al2O3 catalyst increased selectivity with respect to methane and decreased selectivity with respect to C5+. 相似文献
6.
G. A. Kovalenko T. V. Chuenko N. A. Rudina O. V. Skrypnik Yu. G. Maksimova A. Yu. Maksimov 《Kinetics and Catalysis》2009,50(6):899-906
A comparative study of the synthesis of carbon layers, including catalytic filamentous carbon, on the surface of various alumina
modifications was made. The synthesis was performed by the pyrolysis of alkanes (a propane-butane mixture) on Co/Al2O3 supported catalysts. The texture characteristics (specific surface area and pore structure) of the starting supports and
adsorbents with a synthesized carbon layer were studied. The surface morphology of Co/Al2O3 catalysts and the synthesized carbon deposits was studied by scanning electron microscopy. It was found that carbon nanofibers
were formed only on the catalysts prepared by the homogeneous precipitation of Co compounds onto the surface of macroporous
α-Al2O3, whereas carbon deposits on mesoporous aluminum oxides did not exhibit a pronounced fibrous structure. The applicability
of C/Co/Al2O3 carbon-containing adsorbents to the immobilization of the nitrile hydratase enzyme and the preparation of a biocatalyst for
acrylonitrile hydration to acrylamide was considered. 相似文献
7.
Ying Tang Feiqin Chang Rui Zhou Bo Shen Qitong Cheng 《Russian Journal of Applied Chemistry》2016,89(12):2066-2071
Biodiesel containing almost no glycerol has been produced by coupling reaction carried out over K2CO3 supported by calcium oxide as solid base catalysts. The solid base catalysts synthesized by wet impregnation exhibit an exceedingly high activity in biodiesel production. It was found that the reaction time required for the highest yield of biodiesel, 99.2%, can be shortened to 30 min over K2CO3/Al2O3 under the optimum reaction conditions: 8: 1: 1 molar ratio of methanol/DMC/oil, 30 wt % K2CO3/Al2O3 catalyst, and 65°C reaction temperature. Solid basic catalysts examined in the study were characterized by BET surface area, XRD, CO2-TPD, and SEM techniques. The strong interaction between K2CO3 and the support yields a new basic active site, which can be probably responsible for the high activity of K2CO3/Al2O3. 相似文献
8.
M. D. Smolikov K. V. Kazantsev E. V. Zatolokina D. I. Kir’yanov E. A. Paukshtis A. S. Belyi 《Kinetics and Catalysis》2010,51(4):584-594
The state of surface Pt atoms in the Pt/SO4/ZrO2/Al2O3 catalyst and the effect of the state of platinum on its adsorption and catalytic properties in the reaction of n-hexane isomerization were studied. The Pt-X/Al2O3 alumina-platinum catalysts modified with various halogens (X = Br, Cl, and F) and their mechanical mixtures with the SO4/ZrO2/Al2O3 superacid catalyst were used in this study. With the use of IR spectroscopy (COads), oxygen chemisorption, and oxygen-hydrogen titration, it was found that ionic platinum species were present on the reduced
form of the catalysts. These species can adsorb to three hydrogen atoms per each surface platinum atom. The specific properties
of ionic platinum manifested themselves in the formation of a hydride form of adsorbed hydrogen. It is believed that the catalytic
activity and operational stability of the superacid system based on sulfated zirconium dioxide were due to the participation
of ionic and metallic platinum in the activation of hydrogen for the reaction of n-hexane isomerization. 相似文献
9.
A. O. Turakulova E. V. Golubina E. S. Lokteva A. V. Korotkov V. V. Lunin 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2011,85(3):402-407
Deposited palladium catalysts of the hydrodechlorination of 1,3,5-trichlorobenzene were studied. Pure zirconium and aluminum
oxides and ZrO2-Al2O3 mixtures with 1, 5, and 10 mol % Al2O3 prepared by coprecipitation were used as supports. Palladium was deposited by the precipitation of its hydroxide on supports.
Catalysts on binary supports (ZrO2 + 1% Al2O3 and ZrO2 + 5% Al2O3) exhibited higher activity and stability in hydrodechlorination compared with catalysts on pure supports. The suggestion
was made that the high activity and stability of these systems in hydrodechlorination was related to the formation of binary
oxide in the interaction of ZrO2 with palladium oxide at the stage of annealing of the catalyst precursor. Binary oxide, which was a center of the activation
of the C-Cl bond, was simultaneously a source of active hydrogen. The presence of various palladium states in catalysts was
substantiated by the temperature programmed reduction method. 相似文献
10.
A. Kirilin P. Mäki-Arvela K. Kordas A. -R. Leino A. Shchukarev D. Boström J. -P. Mikkola L. M. Kustov T. O. Salmi D. Yu. Murzin 《Kinetics and Catalysis》2011,52(1):72-76
One-pot synthesis of R-1-phenyethylacetate at 70°C was investigated using three different catalysts simultaneously, namely a bimetallic PdZn/Al2O3 as a hydrogenation catalyst, an immobilized lipase as an acylation catalyst and Ru/Al2O3 as a racemization catalyst. The most active bimetallic catalyst was PdZn/Al2O3 calcined at 300°C and reduced at 400°C, whereas the most selective although less active catalyst was the one being calcined
and reduced at 500°C. The highest selectivity to R-1-phenylethyl acetate over this catalyst was 32 at 48% conversion. Ru/Al2O3 was confirmed to have a positive effect on the formation of the desired product, although it was not very active in the racemization
during one-pot synthesis. 相似文献
11.
(1.2–8.3)%FeOх/Al2O3 monolith catalysts have been prepared by impregnating alumina with aqueous solutions of iron(III) nitrate and oxalate and have been tested in NH3 oxidation and in the selective decomposition of N2O in mixtures resulting from ammonia oxidation over a Pt–Rh gauze pack under conditions of nitric acid synthesis (800–900°C). In the case of the support calcined at 1200°C, the catalyst is dominated by bulk Fe2O3 particles localized on the Al2O3 surface. The activity of these samples in both reactions decreases with a decreasing active component content, thus limiting the potential of Fe2(C2O4)3 · 5H2O, an environmentally friendlier but poorly soluble compound, as a substitute for Fe(NO3)3 · 9H2O. Decreasing the support calcination temperature to 1000°C or below leads to the formation of a highly defective Fe–Al–O solid solution in the (1.2–2.7)%FeOх/Al2O3 catalysts. The surface layers of the solid solution are enriched with iron ions or stabilize ultrafine FeOх particles. The catalytic activity of these samples in both reactions is close to the activities measured for ~8%FeOх/Al2O3 samples prepared using iron nitrate. 相似文献
12.
A. Kirilin P. Mäki-Arvela K. Kordas A. -R. Leino A. Shchukarev D. Boström J. -P. Mikkola L. M. Kustov T. O. Salmi D. Yu. Murzin 《Kinetics and Catalysis》2011,52(1):77-81
One-pot synthesis of R-1-phenyethylacetate at 70°C was investigated using three different catalysts simultaneously, namely a bimetallic PdZn/Al2O3 as a hydrogenation catalyst, an immobilized lipase as an acylation catalyst and Ru/Al2O3 as a racemization catalyst. The most active bimetallic catalyst was PdZn/Al2O3 calcined at 300°C and reduced at 400°C, whereas the most selective although less active catalyst was the one being calcined and reduced at 500°C. The highest selectivity to R-1-phenylethyl acetate over this catalyst was 32 at 48% conversion. Ru/Al2O3 was confirmed to have a positive effect on the formation of the desired product, although it was not very active in the racemization during one-pot synthesis. 相似文献
13.
Yu. V. Larichev B. L. Moroz E. M. Moroz V. I. Zaikovskii S. M. Yunusov E. S. Kalyuzhnaya V. B. Shur V. I. Bukhtiyarov 《Kinetics and Catalysis》2005,46(6):891-899
The Ru-Cs+/MgO and Ru-Cs+/γ-Al2O3 catalysts, which were prepared by an impregnation method using RuOHCl3 and Cs2CO3 as precursor compounds and reduced with H2 at 450°C, are characterized by X-ray diffraction, high-resolution transmission electron microscopy (with X-ray microanalysis), and X-ray photoelectron spectroscopy (XPS). The Cs+/MgO(Al2O3) systems, Ru-Cs+ black, and model systems prepared by cesium sputtering onto polycrystalline ruthenium foil are studied as reference samples. It is found that, in the Ru-Cs+/MgO sample, cesium is present as a Cs2 + xO cesium suboxide, which weakly interacts with the support, localized on the surface of Ru particles or near them. In the case of Ru-Cs+/γ-Al2O3, cesium occurs as a species that is tightly bound to the support; this is likely surface cesium aluminate, which prevents promoter migration to Ru particles. The Ru-Cs+/MgO sample exhibits a considerable shift of the Ru3d line in the XPS spectra toward lower binding energies, as compared to the bulk metal. It is hypothesized that this shift is due to a decrease in the electron work function from the surface of ruthenium because of the polarizing effect of Cs+ ions in contact with Ru particles. Based on the experimental results, the great difference between the catalytic activities of the Ru-Cs+/MgO and Ru-Cs+/γ-Al2O3 systems in ammonia synthesis at 250–400°C and atmospheric pressure is explained. 相似文献
14.
A series of Pd/Al2O3–ZrO2 catalysts were prepared to be used in methane oxidation. The effect of the addition order of metal alkoxides on the texture,
structure and catalytic properties of the solids is studied. The control of the preparation parameters is achieved via sol
gel way as an attractive route of the preparation of these catalysts. N2 physisorption, XRD, Scanning Electronic Microscopy (SEM) and H2 chemisorption are the main techniques used to characterize the prepared Pd/Al2O3–ZrO2 catalysts. Textural analysis reveals the mesoporosity of all the catalysts independently of the addition order of alkoxides
while surface area is more pronounced when the aluminium alkoxide is added before or with the zirconium precursor. XRD patterns
show the development of the zirconia tetragonal phase for all the catalysts. Better metallic dispersion is obtained when aluminium
alkoxide is added first which can be justified by the high homogeneity observed on the corresponding catalyst as revealed
by SEM technique. 相似文献
15.
Yan-Hua Zhang Hai-Long Zhang Yi Cao Yi Yang Bao-Qiang Xu Ming Zhao Mao-Chu Gong Hai-Di Xu Yao-Qiang Chen 《Chemical Papers》2016,70(10):1370-1379
A series of Co-modified Ce0.5Zr0.5O2 catalysts with different concentrations of Co (mass %: 0, 2, 4, 6, 8, 10) was investigated for diesel soot combustion. Ce0.5Zr0.5O2 was prepared using the coprecipitation method and Co was loaded onto the oxide using the incipient wetness impregnation method. The activities of the catalysts were evaluated by thermogravimetric (TG) analysis and temperature-programmed oxidation (TPO) experiments. The results showed the soot combustion activities of the catalysts to be effectively improved by the addition of Co, 6 % Co/Ce0.5Zr0.5O2 and that the 8 % Co/Ce0.5Zr0.5O2 catalysts exhibited the best catalytic performance in terms of lower soot ignition temperature (Ti at 349°C) and maximal soot oxidation rate temperature (Tm at 358°C). The reasons for the improved activity were investigated by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), H2 temperature-programmed reduction (H2-TPR), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). These results revealed that the presence of Co could lower the reduction temperature due to the synergistic effect between Co and Ce, thereby improving the activity of the catalysts in soot combustion. The 6 % Co catalyst exhibited the best catalytic performance, which could be attributed to the greater amounts of Co3+ and surface oxygen species on the catalyst. 相似文献
16.
A study was carried out on the properties of Ni/Al2O3 and Cu-ZnO/Al2O3 composites supported on ceramic honeycomb monoliths made from synthetic cordierite in the carbon dioxide conversion of methane
and the partial oxidation of methanol. The structured nickel-alumina catalysts are significantly more efficient than the conventional
granulated catalysts. The improved working stability of these catalysts was achieved by adjusting the acid-base properties
of the surface by introducing sodium and potassium oxides, which leads to inhibition of surface carbonization. The hydrogen
yield was close to 90% in the partial oxidation of methanol with a stoichiometric reagent ratio in the presence of the Cu-ZnO/Al2O3/cordierite catalyst. A synergistic effect was found, reducing the selectivity of CO formation in the presence of the Cu-ZnO
catalyst relative to samples derived from the individual components Cu and ZnO.
__________
Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 43, No. 5, pp. 299–306, September–October, 2007. 相似文献
17.
S. I. Sulima V. G. Bakun R. E. Yakovenko N. P. Shabel’skaya A. N. Saliev G. B. Narochnyi A. P. Savost’yanov 《Kinetics and Catalysis》2018,59(2):218-228
The physico-chemical characteristics and microstructure of cobalt silica gel catalysts with an Al2O3 additive (up to 10%) for the synthesis of hydrocarbons by the Fischer–Tropsch method are studied using a set of methods including X-ray diffraction, BET, IR spectroscopy, and temperature-programmed reduction of H2, as well as scanning and transmission electron microscopy. Phases with a spinel structure, Со3О4, CoAl2O4, and solid solutions on their basis are identified in the samples. The addition of Al2O3 changes the degree of heterogeneity and the orientation of the cobalt crystallites in the oxide and reduced forms of the catalysts. Addition of 1% Al2O3 stabilizes Со3О4 in the spinel form with a structure close to the normal one and promotes the formation of cobalt with a unimodal distribution of particles with an average size of 8 nm. The catalyst is characterized by maximum activity and selectivity with respect to C5+ carbons. 相似文献
18.
A. Yu. Kapran L. M. Alekseenko S. N. Orlik 《Theoretical and Experimental Chemistry》2009,45(5):338-342
Cerium dioxide as a component of CuO-ZnO-CeO2/Al2O3/cordierite catalysts stabilizes their action in the decomposition of methanol by preventing carbon deposition on the surface
and facilitating hydrogen formation with selectivity and yield in the range 85–96%. The optimal indices for this reaction
are obtained for a CeO2-CuO/Al2O3/cordierite sample prepared using an ammonium precursor for cerium, (NH4)2Ce(NO3)6. This catalyst displays enhanced reductive capacity relative to the analogous CeO2-CuO composition prepared using Ce(NO3)3·6H2O. 相似文献
19.
Liquid-phase reduction NO
3
−
using monometallic and bimetallic catalysts (5% Rh/Al2O3, 5% Rh-0.5% Cu/Al2O3, 5% Rh-1.5% Cu/Al2O3, 5% Rh-5% Cu/Al2O3 and a physical mixture of 5% Rh/Al2O3 and 1.5% Cu/Al2O3) was studied in a slurry reactor operating at atmospheric pressure. Kinetic measurements were performed for a low concentration
of nitrate (0.4 × 10−3−3.2 × 10−3 mol dm−3) and the temperature range 293–313 K. From the experimental data, it was found that the reduction of nitrate is first order
with respect to nitrate. On the basis of the rate constants, the apparent activation energy was established using a graphic
method.
Published in Russian in Kinetika i Kataliz, 2007, Vol. 48, No. 6, pp. 881–886.
This article was submitted by the authors in English. 相似文献
20.
This work is focused on the role of gold and Al3CrO6 support for physicochemical properties, and catalytic activity of supported nickel catalysts in partial oxidation of methane
(POM). Catalysts, containing 5% Ni and 5% Ni-2% Au active phases dispersed on mono- (Al2O3, Cr2O3) and bi-oxide Al3CrO6 support, were investigated by TPR, BET and XRD methods, and the activity tests in POM reaction were carried out. Bimetallic
Ni-Au catalysts dispersed on Al3CrO6 support remained highly stable and active. The amorphous binary oxide Al3CrO6 can stabilize considerable amount of Cr4+, Cr5+, and Cr6+ species in Ni-Au/Al3CrO6 catalyst network during its calcination in the air. Nickel supported on binary oxide Ni/Al3CrO6 can form Ni(III)CrO3 bi-oxide phase in reductive conditions. During TPR H2 reduction of Ni-Au/Al3CrO6 catalyst chromium(II) oxide Cr(II)O phase is observed. After POM reaction the existence of bimetallic Au-Ni alloy was experimentally
confirmed on mono-oxide Al2O3 support surface, but its formation was not identified on bioxide Al3CrO6 support.
Published in Russian in Kinetika i Kataliz, 2009, Vol. 50, No. 1, pp. 149–156.
The article is published in the original.
Based on a report at the VII Russ. Conf. on Mechanisms of Catalytic Reactions (with international participation), St. Petersburg,
July 2–8, 2006. 相似文献