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R. Gomez F. Tzompantzi T. Lopez O. Novaro 《Reaction Kinetics and Catalysis Letters》1994,53(2):245-251
Mixed ZrO2–SiO2 oxides were prepared by the sol-gel method and used as supports for platinum catalysts. Activity tests show that Pt/ZrO2–SiO2 catalysts can be used in the aromatization of n-heptane. 相似文献
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G. Angel F. Tzompantzi R. Gómez G. Baronetti S. Miguel O. Scelza A. Castro 《Reaction Kinetics and Catalysis Letters》1990,42(1):67-72
Platinum-tin/alumina supported catalysts have been studied. The TPR results show an assisted reduction of tin by platinum. The effect of alloying in cyclohexane dehydrogenation, o-xylene hydrogenation and cyclopentane hydrogenolysis is discussed.
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Mantilla A Tzompantzi F Ferrat G López-Ortega A Romero E Ortiz-Islas E Gómez R Torres M 《Chemical communications (Cambridge, England)》2004,(13):1498-1499
Oligomerization reaction was carried out at room temperature using sulfated titania as catalyst. Total isobutene conversion was obtained with high stability for a long period of time. In case of deactivation, total reactivation of the catalyst was reached. 相似文献
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A. Barrera J.A. Montoya P. del Angel J. Navarrete M.E. Cano F. Tzompantzi A. López-Gaona 《Journal of Physics and Chemistry of Solids》2012,73(8):1017-1025
The surface properties of Pd and Pd–Pt catalysts supported on binary ZrO2–WOx and ternary ZrO2–Al2O3–WOx oxides prepared by the sol–gel method were studied. Special attention was paid to the study of the texture of the catalysts as well as the chemical state of tungstated zirconia and tungstated zirconia promoted with alumina in the palladium catalysts. The catalysts were tested in the isomerization of n-hexane and were characterized by N2 physisorption, XRD, TPR, Raman spectroscopy, XPS and FT-IR of adsorbed pyridine. The catalysts had bimodal pore size distributions with mesopores in the range 55–70 Å and macropores of 1000 Å in diameter. The catalysts had a surface WOx coverage (4.4–6.0 W nm?2) lower than that of the theoretical monolayer (7.0 W nm?2). A lower acidity of the ternary ZrO2–Al2O3–WOx oxide as compared to the binary ZrO2–WOx oxide was found. Higher activity in the isomerisation of n-hexane was obtained in the Pd–Pt catalysts supported on ternary ZrAlW oxides prepared by sol–gel that is correlated with the coexistence on the surface of W4+ (WO2) or W0 and W6+ (Al2(WO4)3) species, ZrO2 in the tetragonal phase and a high amount of ZrOx suboxides species in a low oxidation state (Zr3+ and Zr2+). 相似文献
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López Tessy Tzompantzi F. Hernández-Ventura J. Gómez R. Bokhimi X. Pecchi G. Reyes P. 《Journal of Sol-Gel Science and Technology》2002,24(3):207-219
Sol-gel zirconia-silica oxides were synthesized with two zirconium precursors, zirconium n-butoxide and zirconium acetylacetonate, and two different hydrolysis catalysts, HCl and H2SO4. The samples prepared with HCl were additionally sulfated with a 1 M solution of H2SO4. Characterization was performed with FTIR and 29Si-MAS-NMR spectroscopy, as well as with nitrogen adsorption. Because zirconium and silicon alkoxides have different hydrolysis rates, it was necessary to perform a pre-hydrolysis of the silicon alkoxide before mixing. The atom distribution in the ZrO2-SiO2 system depended on the zirconium precursor, which also determined the zirconium incorporation in the silica lattice, which was greater for zirconium acetylacetonate. The zirconium precursor also was responsible for the silanol concentration, which increases when samples were sulfated. Sulfating stabilizes the specific surface area. On sulfate samples calcined at 800°C BET areas larger than 500 m2/g were obtained. 相似文献
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T. López M. Alvarez F. Tzompantzi M. Picquart 《Journal of Sol-Gel Science and Technology》2006,37(3):207-211
Because of its semiconductor properties, sol-gel zirconia can be used as a photocatalyst. When zirconia is doped with transition
metals, its electronic properties are modified. In this work, sol-gel Mn/ZrO2 and ZrO2 materials were tested for photocatalytic degradation of 2,4-dichlorophenoxiacetic acid and 2,4,6-trichlorophenol. The powders
were characterized by XRD, UV-Vis and Raman spectroscopy. The apparent rate constants were calculated assuming pseudo-first
order kinetics. The results reveal that ZrO2 is effective as a photocatalyst; moreover, its photocatalytic properties improve when it is doped with manganese. 相似文献
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Photocatalytic Activity in the 2,4-Dinitroaniline Decomposition Over TiO2 Sol-Gel Derived Catalysts 总被引:3,自引:0,他引:3
Tessy Lopez R. Gomez E. Sanchez F. Tzompantzi L. Vera 《Journal of Sol-Gel Science and Technology》2001,22(1-2):99-107
Titania was prepared by the sol-gel method from titanium alkoxide. Depending on the pH of the gelling solution, specific surface areas between 88 and 10 m2/g were obtained. The band gap (E
g) of the samples was found between 3.05 and 3.32 eV. In samples gelled at pH5 and 9 and calcined at 400°C only anatase phase is observed, while for pH3 and pH7 brookite, anatase and rutile or anatase-rutile phases coexist. It was found that the photoactivity in the 2,4-dinitroanailine decomposition depends on the E
g and on the crystalline phases. The highest activity corresponds to the catalysts having the lowest E
g and more than one crystalline phases co-existing. 相似文献
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