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The preparation and study of catalytic system Cu(O)-CeO2 using surface analytical methods
Šmíd, Břetislav ; Matolínová, Iva (advisor) ; Plšek, Jan (referee) ; Sofer, Zdeněk (referee)
Title: The preparation and study of catalytic system Cu(O)-CeO2 using surface analytical methods Author: Břetislav Šmíd Department: Department of Surface and Plasma Science Supervisor of the doctoral thesis: Doc. Mgr. Iva Matolínová, Dr. Abstract: This work is concerned with a study of copper/copper oxide - cerium dioxide systems and their interaction with CO and H2O molecules. Investigated samples were prepared in the form of powder catalysts and also as very well defined model inverse systems. The low temperature CO oxidation powder catalysts were studied by means of XPS, XRD, SEM, TEM and in micro-reactor system allowing the CO oxidation examination. The study of H2O adsorption and co-adsorption of H2O with CO were carried out on model inverse systems CeOx(111)/Cu(111) in ultra-high vacuum conditions using X-ray, synchrotron radiation (SRPES), resonant (RPES) photoelectron spectroscopies and LEED. It was observed on the stoichiometric surface water adsorbs molecularly at 120 K while on the reduced surface and surface of CeO2 islands on Cu(111) the H2O adsorption is partially dissociative with formation of OH groups. The increase of Ce3+ species (i.e. surface reduction) observed after H2O adsorption was explained as an electronic effect of the Ce 4f charge accumulation and Ce 5d charge depletion....
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The preparation and study of catalytic system Cu(O)-CeO2 using surface analytical methods
Šmíd, Břetislav
Title: The preparation and study of catalytic system Cu(O)-CeO2 using surface analytical methods Author: Břetislav Šmíd Department: Department of Surface and Plasma Science Supervisor of the doctoral thesis: Doc. Mgr. Iva Matolínová, Dr. Abstract: This work is concerned with a study of copper/copper oxide - cerium dioxide systems and their interaction with CO and H2O molecules. Investigated samples were prepared in the form of powder catalysts and also as very well defined model inverse systems. The low temperature CO oxidation powder catalysts were studied by means of XPS, XRD, SEM, TEM and in micro-reactor system allowing the CO oxidation examination. The study of H2O adsorption and co-adsorption of H2O with CO were carried out on model inverse systems CeOx(111)/Cu(111) in ultra-high vacuum conditions using X-ray, synchrotron radiation (SRPES), resonant (RPES) photoelectron spectroscopies and LEED. It was observed on the stoichiometric surface water adsorbs molecularly at 120 K while on the reduced surface and surface of CeO2 islands on Cu(111) the H2O adsorption is partially dissociative with formation of OH groups. The increase of Ce3+ species (i.e. surface reduction) observed after H2O adsorption was explained as an electronic effect of the Ce 4f charge accumulation and Ce 5d charge depletion....
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Study of physical properties of metallic nanostructures with induced magnetic anizotropy
Jesenská, Eva ; Veis, Martin (advisor) ; Kouřil, Karel (referee)
The aim of this thesis is a systematic study of physical properties of magnetic multilayered nanostructures. Namely it include multilayered spin valves NiFe/Cu/Co with magnetic anisotropy iduced by magnetic field applied during the deposition. Induced magnetic anisotropy influences exchange interactions between magnetic layers and so it gives the possibility to control magnetic properties of nanolayers. This is important for applications in MRAM, magnetoresistive read heads and spin-transfer-torque devices. Magnetooptic spectroscopy and Kerr effect hysteresis loop measurement were used as effective probe techniques. Secondly we examinated Ar3+ rf sputtering influence on multilayer interface quality level. We found out, that Ar3+ irradiation during deposition process has a possitive effect on interface quality.
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Equipment for Disposal of Waste Gases of Catalytic Oxidation
Brummer, Vladimír ; Martinec, Jan (referee) ; Leštinský, Pavel (referee) ; Bébar, Ladislav (advisor)
This thesis deals with the design of the equipment and documentation for the design of equipment for the removal of volatile organic compounds (VOC) and carbon monoxide (CO) by catalytic oxidation and the selection of appropriate technological conditions for this technology. Introduction is devoted to familiarization with the field of the catalytic oxidation, used catalysts, catalyst supports and their active components. Advantages and disadvantages of the use of catalytic oxidation versus thermal incineration are outlined and currently applicable legislative terms for VOC and CO emissions are listed. In the next part of the thesis the fundamental mathematical tools and research findings available for catalytic reactor model designed primarily for monolithic catalysts are summarized. Presented kinetic model considers continuous reactor with plug flow of gas and adiabatic heating by oxidation reactions corrected for the heat loss of the reactor. The next chapter discusses the design of the new prototype of the catalytic oxidation pilot plant (i.e. the reactor incl. peripherals) primarily intended for monolithic catalysts and bulk catalysts in the form of the fixed bed. The basis for the design and sizing are material and energy balances in the ChemCAD for different intended use of the unit, from which boundary conditions of the unit operating parameters arises. Pilot plant has been designed and built, functionality tests was scheduled also with consecutive obtaining of experimental data not only for the reactor kinetic model. Results of the model for the catalytic combustion were in good agreement with measured data. The next part includes two industrial case studies of the catalytic oxidation process usage for the chemical industry. In particular it was dealt with a replacement of the non-catalytic combustion for the catalytic for VOC abatement from chemical production plants off-gas streams of the company Momentive Specialty Chemicals in Sokolov and German city Leuna. These case studies have brought many valuable experimental and technological knowledge from long-term pilot tests and also verification of design concept, thanks to which it was later possible to design a pilot unit for removal of pollutants in premises of NETME Centre and among other to economically evaluate the usage of catalytic oxidation for the off gas cleaning, in comparison with traditional combustion, in two completely different individual cases. This information was valuable and necessary for the verification of theoretical assumptions of the thesis on specific conditions of two different industrial productions. Based on acquired practical experience and theoretical background, guidelines for designing of devices for VOC and CO removal in the industry were developed.
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Thermal Desorption Spectroscopy (TDS) and its Application for Research of Surface Processes
Potoček, Michal ; Čech, Vladimír (referee) ; Pavlík, Jaroslav (referee) ; Dub, Petr (advisor)
ermal desorption spectroscopy (TDS) is a common method for surface analysis of adsorbed molecules. In chapter 1 the work deals with the theoretical background of this method and shows the principles of a desorption process influenced by subsurface diffusion. Chapter 2 first shows application of TDS for detection of surface molecules and determination of binding energy.Experiments were mainly focused on ditermination of surface adsorbents and impurities on Si wafers. The second part of chapter 2 describes desorption of atoms of a Ga layer on Si surface and their subsurface diffusion. A Ga diffusion process was also observed by with secondary ion mass spectrometry (SIMS) and numerically simulated.
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Aplication of SPM in study and modification of ultrathin films Pt, Co and graphene
Lišková, Zuzana ; Červenka,, Jiří (referee) ; Bartošík, Miroslav (advisor)
This diploma thesis deals with the preparation of the very thin films and their investigation by scanning probe microscopy methods. The ultrathin films of Pt on Pt(111) were created by pulsed laser deposition and the ultrathin films of Co on Pt(111) were deposited by thermal evaporation. The coverage of the substrate was much smaller than one monolayer (in order of hundredths of monolayer). The nucleation theory was verified by these experiments using so-called Onset method. Further graphene sheets were prepared on layer of Si/SiO2 by the mechanical exfoliation from the graphite crystal. The fabricated graphene sheets were studied by micro-Raman spectroscopy, microreflectometry, atomic force microscopy and similar techniques. These methods proved the thinnest graphite layers were consisted of two graphene monolayers.
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Fabrication of Nanostructures Using Atomic Force Microscopy
Doupal, Antonín ; Škoda, David (referee) ; Bartošík, Miroslav (advisor)
This bachelor thesis deals with fabrication of nanostructures using atomic force microscopy. The theoretical part gives a brief introduction into atomic force microscopy and local anodic oxidation and it is based on literature retrieval. The experimental part is concentrated on investigation of influence of operational parameters (tip-sample voltage, speed of the tip) on dimensions of LAO nanostructures on Si(111). Further the selective growth of cobalt and gallium on such oxide nanostructures is observed and analysed.
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