National Repository of Grey Literature 18 records found  1 - 10next  jump to record: Search took 0.00 seconds. 
Co-Mn Mixed Oxide Catalysts Supported on Stainless Steel Meshes Prepared by Hydrothermal Method.
Dvořáková, M. ; Balabánová, Jana ; Topka, Pavel ; Kovanda, F. ; Jirátová, Květa
In this study, we prepared the Co-Mn mixed oxides supported on stainless steel meshes by simultaneous precipitation of Co and Mn nitrates in the presence of hydrolyzing urea under hydrothermal conditions, followed by heating at 500 °C in air.
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Preparation of Palladium Catalysts Supported on Activated Carbons from Agricultural Waste Biomass.
Soukup, Karel ; Topka, Pavel ; Cruz, G.J.F. ; Hejtmánek, Vladimír ; Šolcová, Olga
In the framework of the presented study, the low-cost activated carbons from tropical agricultural waste biomass including cocoa pod husks (denoted as CPH-AC) were prepared. The raw materials collected in Tumbes region in Peru were mixed with activating agent based on ZnCl2 in the weight ratio of 1/1. Subsequently, the mixture was put in a ceramic reactor and afterwards in a horizontal oven to be directly carbonized under nitrogen atmosphere. The temperature increased with the rate of 10 min/min until a final carbonization temperature of 600°C was reached and it was kept during 2 h.\n
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MoO3 supported on mesoporous molecular sieves - new catalysts for alkene metathesis and alkyne polymerization
Topka, Pavel ; Čejka, Jiří (advisor) ; Červený, Libor (referee) ; Hlubucek, Vratislav (referee)
Comprehensive Summary of PhD Thesis MoO3 supported on mesoporous molecular sieves - new catalysts for alkene metathesis and alkyne polymerization MoO3 nanesený na mesoporesních molekulových sítech - nové katalyzátory pro metathesi alkenů a polymerizaci alkinů (souhrn disertační práce) Ing. Pavel Topka J. Heyrovský Institute of Physical Chemistry of the ASCR, v. v. i. Department of Physical and Macromolecular Chemistry Faculty of Science, Charles University in Prague Prague, 2008 2 Introduction Modern homogeneous catalysts for metathesis reactions are based on stable carbene complexes especially of Ru, Mo, and W [1]. For large-scale industrial applications, heterogeneous catalysts remain the preferable choice because of low cost, high stability, easy catalyst regeneration and the possibility of easier separation of the catalyst from the reaction mixture. Typical examples are MoO3/SiO2, WO3/SiO2 and Re2O7/Al2O3, without or with cocatalyst (usually tetraalkyltin). Tungsten and molybdenum oxide catalysts require higher reaction temperatures, where side reactions decreasing metathesis selectivity can occur. Only rhenium oxide catalysts exhibit a high activity and selectivity at reaction temperatures below 100 řC. Supported molybdenum oxide catalysts have received much attention because they are widely used in...
Total Oxidation of Ethanol over Au/Ce0.5Zr0.5O2 Catalysts.
Topka, Pavel ; Kaluža, Luděk ; Gaálová, Jana
The aim of this work was to investigate in a detail the effect of Au loading on the catalytic performance of ceria-zirconia supported catalysts in the total oxidation of ethanol.
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Sorption Ceramic Membranes with a Functionalized Surface Layer
Zub, Yu.L. ; Tomina, V.V. ; Melnyk, I.V. ; Stolyarchuk, N.V. ; Nazarchuk, H.I. ; Sliesarenko, V.V. ; Sliesarenko, V.M. ; Topka, Pavel ; Šolcová, Olga
In the current work, we have considered and compared the deposition on the surface of ceramic membrane of the polysiloxane layers with different functional groups, such as ≡Si(CH2)3SH, ≡Si(CH2)3NH2, and ≡Si(CH2)2P(O)(OH)2, and ≡Si(CH2)3NHC(S)NHC2H5. We have also reported the fabrication of ceramic membranes with bifunctional polysiloxane surface layers, containing two types of complexing groups of different nature, or (fluoro)alkyl groups along with complexing groups. Tetraethoxysilane and bis(triethoxy)silane structuring agents were used in the study. The identification of the deposited layers on the membrane surface was carried out by IR spectroscopy. It was shown by SEM, that the functionalized layers themselves are usually formed by 50-70 nm nanoparticles and their porous structure depends on several fabrication factors.
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Preparation and Characterization of Nanofibrous Catalysts for Environmental Applications
Soukup, Karel ; Topka, Pavel ; Hejtmánek, Vladimír ; Petráš, D. ; Šolcová, Olga
The aim of the study was focused on detailed description of the influence of the preparation of palladium and platinum catalysts supported on polymeric nanofibers based on poly(2,6-dimethyl-1,4-phenylene) oxide on their catalytic performance. The catalytic activity of the prepared electrospun catalysts was investigated by means of model reaction based on total oxidation of methanol. Nanofibrous catalyst supports were prepared by electrospinning technique, which represents currently the most using method to produce polymeric nanofibrous mats. This technique is based on the polymeric fiber elongation under the influence of the electrostatic field between two opposite charged electrodes (capillary electrode and the grounded plate).
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Objectives of Centre Competence BIORAF for Recyclable Biological Material Treatment
Šolcová, Olga ; Hajšlová, J. ; Demnerová, K. ; Vosátka, M. ; Jandejsek, Z. ; Bárnet, M. ; Svátek, A. ; Kaštánek, P. ; Hanika, Jiří ; Topka, Pavel
Projekt Bioraf řeší komplexní přeměnu biomasy metodami tzv. zelené chemie na spektrum společensky žádaných produktů s vysokou přidanou hodnotou a energií.
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Electrospun Catalytic Support Prepared by Electrospinning Technique
Soukup, Karel ; Topka, Pavel ; Petráš, D. ; Klusoň, Petr ; Šolcová, Olga
Our work has been focused on preparation of an electrospun catalytic support based on poly(2,6-dimethyl-1,4-phenylene oxide). A set of nanofibrous catalysts were prepared by the wet impregnation technique with the solution of platinum(II) acetylacetonate and subsequent activated by calcination in air.
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