National Repository of Grey Literature 6 records found  Search took 0.00 seconds. 
Preparation and characterization of platinum-based bimetallic catalysts for fuel cells
Supik, Lukáš ; Khalakhan, Ivan (advisor) ; Kúš, Peter (referee)
1 Abstract The main sources of energy in the world are unrenewable sources. However, its reserves should last for next few tens of years and it is necessary to substitute them with alternative sources. Fuel cells are one of the most promising alternative sources of clean energy because they convert the chemical energy of hydrogen into electrical energy with the only byproduct pure water. There exist a wide range of fuel cells and the most important type is the fuel cell with a polymer membrane because it is suitable for mobile applications. One of the main problems of fuel cells is their price. Platinum catalyst enables chemical reactions and the necessity of platinum rises its price. Nowadays, the most promising strategy for overcoming this obstacle is doping platinum with other metals. Bimetallic platinum alloys increase the catalyst's activity and simultaneously decrease its price. This thesis is focused on investigation of catalyst for fuel cell made of platinum- nickel alloy. The catalyst was prepared by magnetron sputtering technique and then its other properties were measured with respect to the amount of platinum and nickel. The goal of this thesis is to study the link between chemical composition and activity of bimetallic layers.
3D tomography of thin film catalysts by means of FIB/SEM techniques
Dinhová, Thu Ngan ; Matolínová, Iva (advisor) ; Khalakhan, Ivan (referee)
One of the actual problems of today society are decreasing sources of fossil fuels. They are raw minerals and by their burning is energy produced. Regarding to the importance of energy in todays world, it's necessary to find an alternative way how to generate energy. A possible solution to this problem are fuel cells, which work on the principle of converting chemical energy into electric energy. At this moment, the development of fuel cells is in progress. In this bachelor thesis, we are concerned with morphology of catalytic layers Pt/CeO2 deposed on a polymer membrane for hydrogen fuel cells. By using of tomography method with focused ion beam system (FIB) we are creating three-dimensional models of their surface structures. 1
Controllable synthesis, treatment and characterization of anodes for Direct Formic Acid Fuell Cell
Bieloshapka, Igor ; Jiříček, Petr (advisor) ; Khalakhan, Ivan (referee) ; Čechal, Jan (referee)
Title: Controllable synthesis, treatment and characterization of anodes for Direct Formic Acid Fuell Cell Author: Mgr. Igor Bieloshapka Department/Institute: Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University Supervisor of the doctoral thesis: Ing. Petr Jiříček, CSc., Institute of Physics of the Czech Academy of Sciences, Division of Solid State Physics, Department of Optical Materials Abstract: At this doctoral thesis, anodes were prepared by novel DC magnetron sputtering technique for direct formic acid fuel cells (DFAFCs). Anode part consisted of support material and catalyst. Carbon cloth and polyaniline were used as a support. Palladium and palladium-copper bimetallic catalysts were deposited on the top of the support. Scanning electron microscope (SEM) and atomic force microscope (AFM) were used for investigation of the morphology of the anodes. Composition and chemical states on the anode part were studied by x-ray photoelectron spectroscopy (XPS). Transmission electron microscope (TEM) together with the XPS technique were used for characterizing graphene oxide (GO) and reduced graphene oxide (RGO) as a promising support for the polymer membrane fuel cells. For decreasing the role of substoichiometric PdCx phase and other contaminations on the surface of...
Study of 3-phase catalytic layers for polymer electrolyte fuel cells and electrolysers
Fuka, Šimon ; Matolínová, Iva (advisor) ; Khalakhan, Ivan (referee)
Title: Study of 3-phase catalytic layers for polymer electrolyte fuel cells and electrolysers Author: Šimon Fuka Department: Department of Surface and Plasma Science Supervisor: doc. Mgr. Iva Matolínová, Dr., Department of Surface and Plasma Science Abstract: The diploma thesis focuses on the study of catalytic layers for Proton Exchange Membrane Fuel Cells (PEMFC) or electrolyzers based on the mixture of platinum and cerium oxide. These layers are prepared by using magnetron sputtering, their properties are studied depending on the deposition parameters or the choice of the substrate by using SEM, AFM, XPS and then tested as an anode in the fuel cell. In addition to the morphology of the catalytic layers, it has been shown that the dispersion of very small nanoparticles of the catalyst with a size of 1-2 nm has a great effect on PEMFC performance. Most of the prepared samples gave maximal and maximal specific performance much higher than the state of art values published for Pt-CeOx system. By studying properties of the layers used as the anode catalysts, this work contributes to the understanding of PEMFC fuel cell behavior and, consequently, to its potential commercialization. Keywords: Fuel cell, cerium oxide, platinum, catalyst, magnetron sputtering
Novel nanocatalysts for fuel cells I: new type bipolar fuel cells
Švenda, Petr ; Matolín, Vladimír (advisor) ; Khalakhan, Ivan (referee)
There is a greater focus on the alternative sources of energy due to the energetic crisis recently. One of the many ways are the fuel cells, which are based on generating electricity by oxidating the hydrogen. A prominent place is occupied by cells with polymer membrane called PEMFC, which are especially suited for mobile applications due to their low operating temperature. The bigest obstacle for commercial use of the PEMFC is the big amount of platinum required for their production. It is necessary to reduce their cost by means of reducing the amount of used platinum while maintaining the same efficiency. One of the ways is using platinum in alloy with another metal instead of using pure platinum. This thesis addresses the alloy of Pt-Co prepared by magnetron sputtering, which exhibits desirable properties. Adding cobalt decreases the potential barrier that must be overcome for catalytic reaction to proceed. This results in higher specific power output of the fuel cell. The goal of this thesis is to examine in more detail the properties of Pt-Co in comparison with Pt.
Preparation and Characterization of Novel Oxide Catalysts for Fuel Cell Applications
Khalakhan, Ivan ; Matolín, Vladimír (advisor) ; Bourgeois, Sylvie (referee) ; Strýhal, Zdeněk (referee)
V Title: Preparation and Characterization of Novel Oxide Catalysts for Fuel Cell Applications Author: Mgr. Ivan Khalakhan Department/Institute: Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University Supervisor of the doctoral thesis: Prof. RNDr. Vladimír Matolín, DrSc., Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University Abstract: Present doctoral thesis focuses mainly on the morphological investigation of novel oxide catalysts prepared by magnetron sputtering deposition for fuel cell applications. Surface characterization techniques such as scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS), were used in this work. In the first chapter, the influences of different preparation parameters on the morphology of CeO2, Au doped CeO2 and Pt doped CeO2 sputtered films were investigated. It was found that morphology and stoichiometry of the catalyst film is strongly dependent on the deposition parameters and the type of substrate. We have also shown that catalyst films prepared by magnetron co-sputtering of platinum and cerium oxide exhibit high catalytic activity as anode in proton exchange membrane fuel cell (PEMFC). High surface area, low platinum loading and excellent...

Interested in being notified about new results for this query?
Subscribe to the RSS feed.