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Investigation of magnetron sputtered Pt-CeO2 thin film catalyst for fuel cell applications
Vorokhta, Mykhailo ; Matolín, Vladimír (advisor) ; Lykhach, Yaroslava (referee) ; Jiříček, Petr (referee)
Title: Investigation of magnetron sputtered Pt-CeO2 thin film catalyst for fuel cell applications. Author: Mgr. Mykhailo Vorokhta Department: Department of Surface and Plasma Science Supervisor: Prof. RNDr. Vladimír Matolín, DrSc. matolin@mbox.troja.mff.cuni.cz Abstract: This doctoral thesis focuses on magnetron sputtered Pt-doped CeO2 thin films that were found to be very active catalysts in proton exchange membrane fuel cells (PEMFC). The films were prepared on different substrates (silicon wafers, carbon nanotubes and flat carbon substrates) and investigated mainly by means of Hard x-ray photoelectron spectroscopy (HAXPES). The HAXPES method showed that deposition of the Pt doped cerium oxide catalyst layers on carbon nanotubes and flat carbon substrates by magnetron sputtering leads to growth of a highly porous "Pt-Ce-O" solid solution film, where platinum is mostly in ionic states, Pt2+ , Pt4+ . The results obtained showed that the mechanism of film growth is strongly influenced by interaction of the Ce atoms with the substrate and their oxidation by oxygen containing RF plasma. The formation of Ptn+ states together with the porous character of the catalyst films are used to explain the high activity of Pt-CeO2 catalyst in PEMFCs. Keywords: magnetron sputtering, cerium oxide, Pt, XPS, SRPES.
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Study of new catalytic materials for proton exchange membrane fuel cells
Homola, Petr ; Matolín, Vladimír (advisor) ; Jiříček, Petr (referee)
Title: Study of new catalytic materials for proton exchange membrane fuel cells Author: Petr Homola Department: Department of Surface and Plasma Science Supervisor: Prof. RNDr. Vladimír Matolín, DrSc. Abstract: Submitted thesis deals with study of thin layers based on platinum and cerium oxides in order to use them in fuel cells with polymer membrane (PEM- FC). A set of samples with different amount of platinum was prepared by means of magnetron sputtering. Samples were investigated by X - ray Photoelectron Spectroscopy (XPS) and results were confronted with sputtering parameters. It was found out that chemical state of platinum is related to its amount in thin layer. The less platinum was contained in thin layer, the less amount of Pt0 state was observed and amounts of Pt2+ and Pt4+ states increased. Furthermore the temperature stability of prepared layers in the interval from room temperature to 250 ◦ C was studied by means of XPS. The adsorption of carbon monoxide was measured by infrared absorption spectroscopy (IRAS). Increasing degree of adsorption on sample probably related to platinum reduction with increased tem- perature was observed. Measurements of other samples were devaluated by strong contamination with nickel carbonyls. Keywords: PEMFC, cerium oxide, magnetron sputtering, XPS, CO adsorption
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Structural study of metal-CeO2/Cu(111) model systems by RHEED
Beran, Jan ; Mašek, Karel (advisor) ; Jiříček, Petr (referee)
The cerium oxide was deposited by reactive vacuum evaporation on the (111) surface of copper single-crystal in oxygen atmosphere at constant substrate temperatures of 25řC, 300řC and 450řC and at increasing temperature from 25řC to 450řC. In each case, the cerium oxide grew epitaxially with the (111) plane parallel to the substrate. The lattice parameter of the oxide increased up to the value of 5,28 during the deposition. At increasing temperature the growth of additional three-dimensional domains with tetrafold symmetry and (100) plane parallel to the surface was observed. Lattice parameter of these domains exhibited the value of 5,36 in the direction parallel to the surface. These domains were also observed by STM. The palladium grew on the cerium oxide surface in form of epitaxial islands having (111) epitaxial plane parallel to the substrate surface. The palladium deposition resulted in the partial reduction of the oxide layer. The reduction was caused by the interaction of the palladium and oxygen atoms leading to the formation of PdO phase. This feature became more pronounced during annealing at 300řC. Annealing at higher temperatures led to coalescence of the palladium islands and thermal induced decomposition of the palladium oxide.
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Safety of technological systems
Jiříček, Petr ; Pavlík, Josef (referee) ; Hammer, Miloš (advisor)
The work deals with the safety of technological systems and can be divided into two main thematic units. The attention in the first theoretic unit is paid to aspects that affect the safety of technological systems during their technical life. It describes, together with elementary norms and acts solving the products safety, the most important principles for creating and analysing the safety. It clarifies the origin of company’s risk management, part of its quality management, mentions the faults in which products can be found and also describes the failures which have the biggest effect on these faults and of course on the safety too. Attention is further paid to the reliability analysis, as the tool that helps to create the products safety in the pre-manufacturing phase and also to technical diagnostic, as the tool to keep the safety in after-manufacturing phase. The second practical unit arithmetically analyses the safety of two high-voltage transformers. For that it was used the database of real operation numerical values that were gained during diagnostic investigations on these transformers. In addition it describes mentioned diagnostics methods and gives the new procedure for analyse of transformers’ safety by criteria matrix and weighted sum approach. The main contribution of the work can be considered the checkout and the evaluation of this procedure for use in elaboration of high-voltage transformers diagnostic values for analyzing their safety.
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Applying Fundamental Analysis When Investing In Stocks Of Selected European Technology Companies
Hasil, Petr ; Jiříček, Petr (referee) ; Rejnuš, Oldřich (advisor)
This thesis deals with the fundamental analysis of stocks of selected European technology companies. This type of analysis is the most widely used method of valuation of the shares. The first part describes the theoretical background of the analysis current economic situation, regression analysis, analysis of corporate shares and methods of intercompany comparison necessary for practical application. In the practical part focuses on the analysis of selected companies and selecting evaluation indicators. Subsequently is determined by corporate analysis the current intrinsic value of the shares. In conclusion, a comparison is made of firms using the methods of intercompany comparison. Based on the results of the analysis will be proposed recommendations for the best investment.
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Proposal of Valuation of the Firm
Cygonková, Lenka ; Jiříček, Petr (referee) ; Karas, Michal (advisor)
This master thesis deals with the proposal of a chosen company by using the income-based methods called Discounted Cash Flow and Economic Value Added. The theoretical part provides the description of the methodology of business valuation process. The practical part presents financial, strategic and SWOT analysis of the company. Furthermore particular valuation methods are applied. In conclusion statement of value is reported.
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Evaluation of the Financial Health of ELEKTROSTAV STRAKONICE, Ltd
Kordíková, Barbora ; Hajdíková, Taťána (advisor) ; Jiříček, Petr (referee)
The thesis deals with an analysis of the economic health of the company ELEKTROSTAV STRAKONICE Ltd. To meet the goals of the thesis several chosen financial analysis indexes will be used. These indexes will be firstly calculated and then used in the assessment of the financial and economic health of the company. The results of the financial analysis will be assessed and compared with results of other companies in the same field of business. If necessary, certain measures of improvement are suggested. The comparison serves as an illustration of what position the company holds in the market.
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Multiple Criteria Decision Making of Stocks Traded in Terms of SPAD
Borovička, Adam ; Kuncová, Martina (advisor) ; Jiříček, Petr (referee)
The subject of the diploma paper is multiple criteria analysis of stocks traded on Prague Stock Exchange in terms of System for Support of the Share and Bond Markets. The first part of theoretical passage discusses an introduction of exchange markets with an emphasis on Czech surrounding. The next extensive segment enters on decision making theory. In this chapter we can study basic ideas and connections in multiple criteria decision making. The most comprehensive section is created by theoretical study of methods in multiple criteria decision making. The last partition deals with share's analysis which is based on an application of suitable methodical approaches developed theoretically more closely in previous parts of the diploma paper. The main goal of the paper represents a release of investment recommendation for a potential investor decided to insert his free financial means into some of the most liquid stocks on Prague Stock Exchange.
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