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Modifikace směsných oxidů Co-Mn-Al promotory a jejich vliv na vlastnosti a aktivitu při oxidaci VOC
Mikulová, Z. ; Jirátová, Květa ; Klempa, Jan ; Kovanda, F.
The influence of the catalysts chemical composition and of the mode of promoters incorporation on the activity and selectivity in VOC oxidation was studied. In total oxidation of toluene, the most active Co4MnAl catalysts were those containing low concentration of potassium regardless the mode of modification, while in ethanol total oxidation the catalyst impregnated with higher potassium concentration (3 wt%) was the most active. Introduction of Pt and Pd in amounts 0.5 or 0.1 wt% into the Co4MnAl catalyst did not improve its catalytic activity. The impregnation method appears to be more effective mode of catalyst modification than the method using an addition of promoters in the stage of coprecipitation of the LDH precursor.
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Příprava a charakterizace tenkých vrstev oxidů zirkonu a titanu
Krejčíková, Simona ; Matějová, Lenka ; Matěj, Z. ; Jirkovský, Jaromír ; Šolcová, Olga
Titania and zirconia belong to nanoporous materials with huge application potential in photocatalysis, dye-sensitized photoelectrochemical cells, electrochromic devices, sensors and other applications, especially in the form of nanolayers. Differences in surface morfology, texture and crystallinity influence their catalytic impact. Therefore special attention is focused on the detailed textural and structural characterizations of thin titania-zirconia nanolayers prepared by sol-gel templated route.
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Kovové materiály pro přechovávání vodíku
Soukup, Karel ; Rogut, J. ; Ludwik-Pardala, M. ; Wiatkowski, M. ; Šolcová, Olga
Another alternative is the redox cycle of iron/iron oxides which is presented here. Hydrogen storage is described as a reduction of iron oxides to metallic iron by hydrogen. Hydrogen production is achieved through the oxidation of iron with water steam. This contribution describes textural and transport properties of solid materials composed of iron and aluminium oxide phases which are believed to be promising for the hydrogen storage process.
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Samonosné pelety z (Al)-SBA-15
Topka, Pavel ; Zub, Yu.L. ; Šolcová, Olga
Self-supporting pellets were successfully formed from SBA-15 and Al-SBA-15 powder without the addition of binder or plasticizer. Prepared self-supporting pellets maintained the porous structure of original powder. In comparison with parent sample, a decrease of mesopore surface area and mesopore volume up to 40 % was noticed in the case of pellets formed with the highest 17.7 MPa pressure. The Al-SBA-15 pellets prepared using 4.7 MPa forming pressure were enough mechanically stable to retain the structural integrity during batch alkylation of toluene with benzyl alcohol at 110 °C. The conversion reached with Al-SBA-15 pellets after 60 min of the reaction was about five times lower than that accomplished with powder Al-SBA-15.
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Strukturní studie tenkých titaničitých vrstev
Šolcová, Olga ; Matějová, Lenka ; Krejčíková, Simona ; Matěj, Z. ; Kužel, R. ; Strýhal, Z.
Our study is focused on the relationship between the number of oxyethylene units in nonionic surfactants used for preparation of a set of various titania layers by dip-coating via the sol-gel method and morphology, roughness, type of titania phase and textural properties of the prepared titania layers. Additionally, the contact angle determination as a rapid and easy method suitable for evaluation of the surface quality of the prepared titania layer has been tested, too.
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Vliv nosiče při hydrodesulfurizaci na sulfidu ruthenia
Gulková, Daniela ; Kaluža, Luděk ; Vít, Zdeněk ; Zdražil, Miroslav
The hydrodesulfurization of thiophene over ruthenium sulfide on Al2O3, MgO, SiO2, TiO2, ZrO2 or active carbon was studied. The catalysts (1, 3 and 6 wt.% Ru) were prepared by impregnation with aqueous RuCl3. The only exception was the Ru/MgO catalyst which was prepared by impregnation with methanolic solution of Ru acetylacetonate. The catalysts were sulfided either in a 10%H2S/H2 or 20%H2S/N2 mixture at 400 oC. Their activity was tested at 400, 370 and 340 oC. The latter catalysts were mostly more active than the former. The difference increased with the loading and depended on support, the highest being with TiO2 and ZrO2 and the lowest with alumina and active carbon. The Ru sulfide catalysts were more active than the Mo/Al2O3 catalyst with corresponding loading. The order of activity was independent of activation method.
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Vliv nosičů gamma-Al2O3, TiO2 a ZrO2 na hydrodesulfurizační aktivitu sulfidů přechodových kovů
Kaluža, Luděk ; Zdražil, Miroslav
A significant effect of ZrO2 and TiO2 supports on the hydrodesulfurization-activity ranking of V, Cr, Mn, Fe, Co, Ni, Mo, Ru, Rh, Pd, W, Re, Os, Ir and Pt sulfides studied was ascertained.
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