|
Chemistry and Chemical Technologies
Doctoral Programme,
Faculty of Chemical Technology
--- Careers--- Programme Details
Ph.D. topics for study year 2025/26Two-dimensional materials as a catalytic support for metal nanoparticles
AnnotationTwo-dimensional (2D) materials exhibit increased catalytic activity in 2D material-supported metallic nanoparticles compared to their bulk counterparts. The increase in activity attributes to specific 2D support-nanoparticle interactions. The thesis focuses on the nanohybrid (2D support-nanoparticle) preparation by various routes, including both the metal introduction after the exfoliation and simultaneous exfoliation and metal deposition. An inherent part of the thesis is a complex and correlated spectroscopic and microscopic characterization of the prepared nanohybrids. Then the final output will be a relation between the synthetic route, material texture, and catalytic performance in model reactions like selective hydrogenations, oxidations, and C-C coupling. Electrochemical methods for process water treatment
AnnotationElectrochemical methods are suitable for water treatment due its simplicity and high efficiency. Main disadvantage is usually high price. Therefore electrochemical methods are used in the case of water of high salinity or otherwise contaminated. This is not possible to be treated by biochemical methods. Application of individual method has to be evaluated with respect to the direct process water composition. Photoelectrochemical removal of pollutants and hydrogen generation from water using solar light
AnnotationProduction of hydrogen as an alternative energy source/carrier is becoming recently very important and intensively studied process. One of the promising options is direct production of hydrogen from water via solar light. Very important process is also removal of persistent pollutants in waters by advanced oxidation processes, one of them is photo-electrochemical oxidation. The topic of the present thesis is the preparation of semiconductor photoanodes and photocathodes (eg. WO3, BiVO4, CuO, CuFeO2, atd.) for photo-electrochemical water splitting or photo-electrochemical removal of persistent pollutants. Different methods of preparation (aerosol pyrolysis, spray pyrolysis, etc. ) will be used and the resulting films will be characterised (XRD, GDS, UV-VIS, BET, SEM) and their photo-electrochemical properties (open circuit potential, photocurrent, IPCE) evaluated. The attention will be given to the influence of composition, crystalline phase, layer thickness and porosity. The best photoanode and photocathode layers will be applied in the tandem solar photo-electrochemical cell and its efficiency for water decomposition to hydrogen and oxygen by sunlight will be determined. Photoelectrochemical systems for conversion of solar light
AnnotationA photoelectric chemical system involving a photoanode, photocathode, membrane and suitable ox/red couple allows the conversion of solar energy into chemical energy. The theme of this thesis is the investigation of possible systems for solar energy conversion with a focus on suitable photoanode and photocathode materials and their combination with suitable electrolytes. Part of the work will be the preparation of selected photoanode or photocathode materials (e.g. Fe2O3, ZnO, WO3, BiVO4, CuO, CuFeO2, etc.) and investigation of their behaviour during long-term photoelectric polarization. Different methods of preparation (aerosol pyrolysis, spray pyrolysis, etc. ) will be used and the resulting films will be characterised (XRD, GDS, UV-VIS, BET, SEM) and their photo-electrochemical properties (open circuit potential, photocurrent, IPCE) evaluated. The attention will be given to the influence of composition, doping, crystalline phase, layer thickness and porosity. Photocatalytically active composite for wastewater treatment
AnnotationAs the consumption of medicinal products increases, the contamination of wastewater with pharmaceutical substances also increases. Most standard wastewater treatment systems cannot completely remove these micropollutants, leading to their release and accumulation in the environment. This poses a potential risk not only to aquatic ecosystems, but also to drinking water sources. For this reason, it is necessary to develop efficient and ecological technologies suitable for the degradation of these contaminants. The aim of this work will be to prepared, characterized and tested the new photocatalytically active composites based on graphitic carbon and titanium dioxide. The photocatalytic properties of the prepared materials will be verified during the degradation of selected pollutants from both model and real wastewater. Required education and skills: • Master degree in chemistry or environmental studies; • systematic and creative approach to work; • conscientious and proactive approach, analytical thinking • independence and team work ability. Catalytic transformation of methane to higher value products
AnnotationThe high attention on the processes of transformation of methane (C2, C3 hydrocarbons eventually) from natural gas or biogas to higher value products is paid at present time. The processes such as non-oxidative catalytic methane aromatization, selective oxidation to methanol or dimethyl ether are used. The suitable catalyst for chosen process will be developed. The effect of the reaction conditions, catalyst carrier and formation of active phase on catalyst on the methane conversion, catalyst stability and yield of products will be studied. Catalysts for alkaline energy conversion devices
AnnotationAlkaline energy conversion technologies represent one of the promising ways to increase the utilization of the installed renewable sources of energy. The advantage of the alkaline technologies lies in the possibility to avoid the necessity of the utilization of the Pt-group metals as catalysts for electrode reactions. On the other hand, the intensity of these technologies is generally lower when compare to alternatives. This work focuses on the synthesis and optimization of the new catalysts, their testing using standard procedures and under the real conditions of the energy conversion devices. Catalysts for the oxidation of volatile organic compounds
AnnotationVolatile organic compounds (VOC) are one of the main contributors to air pollution. They are precursors of photochemical smog (ground-level ozone) and very efficient greenhouse gases (up to 11 times more effective compared to CO2). Furthermore, they are detrimental not only to the environment but also to human health due to their harmful properties (toxic, malodorous, mutagenic, and carcinogenic). Therefore, increasingly strict regulations are being put in place worldwide in order to reduce VOC emissions into the atmosphere. VOCs are emitted from thousands of different sources, such as chemical plants, petroleum refineries, power plants, paint industry, gas stations, dry cleaners, etc. In the industry, the old thermal incineration units are retrofitted with catalytic oxidation technology, which is a green and cost-effective method for the abatement of VOC emissions. The aim of the thesis is the development of new catalysts for VOC oxidation. The activity and selectivity of the prepared catalysts in the oxidation of model VOCs will be correlated with their physicochemical properties in order to identify the factors important for their efficiency. Required education and skills: • Master's degree in chemical engineering, physical chemistry, organic technology, chemical physics or similar; • willingness to do experimental work and learn new things, team work ability. Quaternary ammonium salts as a platform for innovative catalytic processes
AnnotationKvartérní amoniové sole mohou sloužit jako katalyzátory pro řadu významných reakcí z nichž významnou roli zastává cykloadice oxidu uhličitého na epoxidy nebo alkeny vedoucí k cyklickým karbonátům. Další z důležitých reakcí, které mohou být katalyzovány amoniovými solemi, je Knoevenagelova kondenzace aldehydů s nitrily. Tato reakce je významná z hlediska využití v oblasti chemických specialit jako jsou vonné látky nebo intermediáty farmaceutik. Nevýhodou amoniových solí je jejich použití v homogenním reakčním uspořádání, a tedy komplikovaná separace z reakční směsi a nemožnost opakovaného použití. Cílem práce bude příprava heterogenních analog kvartérních amoniových solí, jejich detailní charakterizace a testování jako katalyzátorů ve vybraných reakcích. Bude sledován vliv strukturních vlastností připravených materiálů na jejich katalytickou aktivitu a v neposlední řadě možnost opakovaného použití. Oxygen gas diffusion electrodes
AnnotationKyslíkem depolarizované elektrody mají zásadní význam v řadě elektrochemických aplikací. Vedle chemické výroby se stále více uplatňují i v energetických systémech, jako jsou palivové články a tzv. dýchací akumulátory. Tématem práce bude vývoj a optimalizace kyslíkových difuzních elektrod s ohledem na vlastnosti celého systému. Mathematical modelling of the electrochemical systems
AnnotationMathematical modeling represents an extraordinary powerful tool for deeper understanding of the electrochemical units function and their subsequent optimization. Within the framework of this project the attention will focus on the mathematical description of the local transport of electric current, mass or heat etc. in electrochemical and electromembrane systems (fuel cells, PEM electrolysis, electrodialysis, solid-oxide high temperature electrolysis) and investigation of mechanism and kinetics of electrochemical reactions. The models formulated on the base of PDE equations will be implemented to simulate systems with a practical impact. Mathematical modelling of chemical and membrane processes using universal simulation programs
AnnotationUniversal simulation programs introduce a tool suitable for design of new and optimization of existing industrial technologies. In the frame of this work the static and dynamic models of selected advanced membrane and/or chemical technologies or their parts will be developed using universal simulation programs. By the help of them and computer experiment the behavior of these technologies will be studied. Verification of developed models by experimental data will be implemented. Aim of the work is the improvement of economic and ecological technological parameters. The universal simulation programs from Aspen Technology will be used preferentially. Mathematical models of composite materials prepared by dispersing solid particles of a filler in a liquid polymer matrix
AnnotationThe work is aimed at the mathematical modelling of composite materials, the preparation of which includes the creation of a suspension of solid particles in a liquid mixture of a solvent and a polymer precursor, volume contraction of the suspension caused by evaporating the solvent and by forming a solid polymer matrix. The initial suspension is modelled using the random sequential addition of particles of various shapes. Then, the motion of particles of the filler in the shrinking suspension is simulated. Each model microstructure and the corresponding microstructure of the real composite material sample are characterised using statistical measures and these measures are subsequently compared with each other for the quality of the model to be evaluated. The real microstructures are deduced from digital images of their polished sections that are observed using a scanning electron microscope. Membrane separations of highly concentrated solutions
AnnotationMembrane separations are widely used especially in the water treatment processes. Another key application is in the field of chemical industry, where concentrated solutions are mostly used. However, higher concentrations of solutions bring several problems such as back diffusion, solubility limit and membrane stability to the separation process. It is therefore necessary to understand and describe these phenomena and their influence on the membrane separation process itself to predict the long-term a behaviour of the system. Nanostructured/ composite materials based on TiO<sub>2</sub> for photocatalytic processes in gaseous phase
AnnotationAir polution represents a significant problem which can be conveniently solved by an application of photocatalytic processes. Therefore the aim of the present thesis is the preparation of new photocatalytically active composite materials based on TiO2 and the determination of their adsorption and photocatalytic properties. Titanium dioxide nanotubes prepared by anodic oxidation show a larger active area (compared to planar samples), allowing more efficient removal of polutants from the gaseous phase. The influence of various modifications of TiO2 nanotubes and of operating parameters (flow, humidity and UV intensity) on photocatalytic efficiency will be investigated. The goal is to get the material having at the same time good adsorption properties and at the same time a high ability to remove unwanted volatile substances in the air. Part of the work will use the standard ISO tests for monitoring the kinetics of oxidation reactions (NOx, VOCs) on the surface of the prepared photocatalysts. The important part is the characterization of materials/coatings (XRD, SEM, BET, Raman spectroscopy) and further development of methods allowing the testing of functional properties of the prepared materials/coatings in air treatment. Polymer electrolytes for energy conversion devices
AnnotationPolymer ion selective materials are well established in the many technologies including the environment protection, food industry and large scale production of the basic chemical substances. Energy conversion devices represent the recent but sharply growing field of the ion selective membrane utilization. The work is focused on the complex characterisation of the physio-chemical and electrochemical properties of the developmental ion selective polymer electrolytes. Prediction and experimental determination of transport properties of mixed-matrix membranes
AnnotationThe work is aimed at simulation and experimental determination of transport properties of mixed-matrix membranes that differ from each other in polymer and filler materials. In addition, the membranes containing different fractions of filler particles will be investigated. Statistical treatment of obtained data will accompany the experimental determination of permeability. Permeability will also be modelled on the basis of reconstructed microstructures of the membranes and transport properties of components forming the membranes. Preparation and characterization of mixed matrix membranes for gas separation
AnnotationGas membrane separation represents one of the perspective and energy saving alternative with respect to the present separation processes (PSA, TSA etc.). In the frame of this work the mixed matrix membranes, combining the perspective properties of the both, microporous and polymeric membranes, will be prepared and characterized. The microporous material e.g. ZIF-8, silicalite-1, ETS, FAU, TS-1, AFX, MOF will be used as filler and combined with polyimide matrix. The key issue of mixed matrix membranes preparation which needs to be solved is the adhesion and interface interactions of filler and polymer because of their effects on compactness and selectivity of membrane. The aim of this study is evaluation of different possibilities of microporous and polymer phase modifications with respect to the compactness of membranes and their selectivity and permeability in selected systems of hydrocarbons, CO2 and H2. Preparation of nanofibrous catalysts by electrospinning technique
AnnotationThe main aim of the proposed project is to assess the specific properties of the novel polymeric nanofibrous materials prepared by electrospinning in applications as effective catalyst supports. Other targets of this project will be specifically addressed to the optimization of the electrospinning process parameters concerning properties of the prepared supports, deposition of the catalytically active centers or catalyst precursors, and assessment of the effect of support microstructure on the phenomenological kinetics of model reactions. Studied model reactions will involve both reactions in gas-phase (total oxidation of volatile organic compounds) and liquid-phase (selective hydrogenation of unsaturated carbonyl compounds). Additionally, it will be investigated the possible influence of differences between the polymer surface nature of nanofibers and conventional polymeric catalyst supports on catalytic properties. Required education and skills: • Master's degree in chemical technologies, chemical engineering, or chemistry of materials; • methodical and creative approach to work; • willingness to perform experimental work and learn new issues. Synthesis and chemical modification of layered materials based on Si, Ge, and Si<sub>x</sub>Ge<sub>(1-x)</sub> mixtures
AnnotationLayered low-dimensional materials are auspicious for application in all areas of nanotechnology since properties of these materials depend on the degree of exfoliation. Also, catalysis seems to be an exciting application as a superior effect of a two-dimensional (2D) support on the activity of metal nanoparticles due to specific metal-support interactions. This project is focused on preparation and chemical modification of layered materials based on Si, Ge, and SixGe(1-x) mixtures. The aim is to prepare 2D hundreds-of-micron-sized sheets and nanometer-sized quantum dots (QDs) with high optical and chemical uniformity. Functionalization of the prepared uniform low-dimensional materials allows the application of these materials in fundamental research of phenomena typical for heterogeneous catalysis: I) Study of the exclusive effect of 2D support on the enhanced activity of metal nanoparticles and II) Assessment of accessibility and interconnectivity of pores space in conventional catalysts using 0D QDs with varying size as a pore space probe. Self-cleaning and antibacterial coating based on TiO<sub>2</sub> and ZnO
AnnotationThe main scope of this work is preparation of photocatalytic active coatings/ paints based on TiO2 a ZnO on the appropriate substrate (ceramics, glass, metals, facades, hydraulic binders) by different methods. The important part of the work is films characterization (XRD, SEM, Raman spectroscopy) and development of methods for testing photoactivity and hydrophilic and antibacterial properties of prepared layers. Studied parameters will be the methods of precursor deposition (dip-coating, spraying) and the influence of the binder in the coating and the substrate. Investigation of water electrolysis with proton exchange membrane
AnnotationWater electrolysis represents an important part of the hydrogen economy considered nowadays as a promising approach to the future securing of the human society with electrical energy. Industrial water electrolysis processes established today suffer from several disadvantages when considering its application in the field of energetics. It is mainly its low efficiency and flexibility. Therefore, this process is a subject of interest of numerous research laboratories around the globe. Electrode reaction kinetics, suitable polymer electrolytes and overall process design represent the main issues studied. Corrosion stability of the individual construction materials and recycling of precious metals remain also important topics. Thin films of Metal oxide semiconductors for photoelectrochemical and sensory applications
AnnotationMetal oxide-based semiconductor films (e.g. WO3, Fe2O3, Fe2TiO5....) can be used for a number of photoelectrochemical and sensory applications. Based on the literature review, selected layers of metal oxide-based semiconductors will be prepared and their material (XRD, AFM, SEM), photoelectrochemical (photocurrent, efficiency of photon-to-electron conversion) and sensory properties (resistivity) will be characterized. The optimized films will be used as sensors for the detection of gaseous substances such as hydrogen, NO, NO2, acetaldehyde, etc. Transformation of carbon dioxide into higher value products
AnnotationCurrently, considerable attention is paid to the transformation of carbon dioxide into products of higher utility value such as methane, light hydrocarbons, methanol and others. These include, for example, the processes of methanization, aromatization, disproportionation. At the same time, new ways of supplying energy to activate the C=O bond are being sought. In this work, a suitable catalyst for the selected process will be developed. The influence of reaction conditions, catalyst support and the procedure for forming the active phase on the achieved CO2 conversion, catalyst stability and product yields will be studied. The influence of the catalyst structure on its activity will also be studied. High temperature fuel cells
AnnotationHigh temperature water electrolysis represents a modern technology closely related to the optimization of operational conditions of the traditional as well as novel high capacity power sources used nowadays to the stabilization of the electricity distribution grid. Stabilization requirement is caused by the strongly increasing capacity of the unstable renewable energy sources connected to the distribution grid. High temperature fuel cells with proton exchange membrane
AnnotationAn attention of the numerous laboratories around a globe is focused on the issue of the PEM type fuel cells operational temperature increase above 100 ºC. The globaly accepted approach to solve this problem consists in application of basic polymers impregnated with phosphoric acid as an electrolyte and carbon supported Pt nanoparticles as an electrolyte. The main obstacle of this approach represents leaching of the phosphoric acid into the catalytic layer and its corrosion aggressivenes at the fuel cell operational conditions. Solution of this issue, together with understanding understanding of the degradation processes at elevated temperature represents basic requirement for further development and wider application of this technology in future. Layered double hydroxides as sorbents for biologically active substances
AnnotationDouble layered hydroxides, also known as hydrotalcite or anionic clays, are an important group of materials with a wide range of applications. They can be applied as catalysts, catalyst precursors or ion exchangers, in sorption and decontamination processes. They can also be used for the intercalation of various substances including drugs. The aim of this work will be to prepare these materials, modify their surface with silanol based compounds and to characterize them by suitable methods. The prepared materials will be used as support materials for the immobilization of selected active substances. Green Catalysis: From biomass to fine chemicals
AnnotationPráce se bude zabývat přípravou chemických specialit, jako jsou vonné látky, pesticidy nebo látky pro farmaceutický průmysl. Výchozími látkami pro přípravu budou materiály vycházející z biomasy, například pineny nebo furfural. Bude sledována možnost využití těchto látek, bude prováděna optimalizace reakčních podmínek a bude studován vliv reakčního uspořádání na průběh reakce 2D materials as supports for modern catalytic systems
Annotation2D materials are defined as layered materials with minimum thickness to the physical limit. Graphene is the first example of 2D materials, isolated from natural graphite in 2004 which has been since then extensively investigated in the wide range of potential applications. Beyond graphene, a wide spectrum of 2D materials. Layered 2D materials are characterized by large surface area, uniformly exposed lattice plane, adjustable electronic state, ability of surface defect formation, and possibility of controlled surface functionalization. Because of these unique properties, 2D materials can be utilized in catalysis as the supports for anchoring of catalytic active species/metals. The greatest benefit of using 2D supports is possibility to decrease amount of anchored precious metals necessary for catalyzing of the chemical reaction. The aim of the research work will be preparation of heterogenous catalysts utilizing 2D materials that will be active in basic chemical syntheses as hydrogenations, oxidation or hydroformylations. Experimental work will therefore include preparation of heterogeneous catalyst utilizing 2D materials as the supports for various active metals, as Pt, Pd, Rh, Ru, Ag, Cu, Ni or others. The prepared catalysts will be deeply characterized using available characterization methods (SEM/EDS, TEM, XRD, N2-physisorption, Raman spectroscopy etc.) and finally tested in chosen model reactions. |
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Updated: 20.1.2022 16:26, Author: Jan Kříž