(P4F5 and P4F5A)
The study program covers all aspects of surface physics and thin film technology. It is based on knowledge of physical and chemical properties of solid state surfaces and interfaces and of physical processes related. Studies include problems of basic research in material science and nanophysics, study of surface structures and processes at atomic level, surface catalysis as well as borderline disiplines such as fuel cell technology. Experimental approach is in close relation with theoretical study of problems. The program prepares professionals with a broad foundation in physics, with rich experience in advanced surface experimental techniques and with deep knowledge of surface physics and chemistry.
Research fields are more or less defined by the current projects at our department and it similarly applies to the cooperating institutes of Czech Academy of Sciences.
Nanomaterials group deals with the preparation and characterization of nanomaterials. It aims especially for efficient catalysts for fuel cells and electrolyzers as well as for gas or bio sensors:
Thin film Group is focused on STM/AFM characterization of interactions of single atoms and organic molecules with various surfaces:
Surface Physics Group is focused on the investigation of physicochemical properties of technologically relevant surfaces and surface nanostructures:
It's always a good idea, if you find a topic for you, to contact supervisor first, i.e., prior application!
Supervisor: Ing. Nataliya Tsud, Dr.
Usage of inorganic materials for the development of organic electrodes with well-defined morphology and physicochemical properties is a promising route for the construction of novel sensing devices for monitoring of the environmental pollutants. Among other materials, cerium dioxide became attractive because of its specific electronic properties and successful applications in catalytic and healthcare systems. Recently, we showed that cerium oxide thin films can be used as an enzyme-free electrode material for electrochemical detection and quantification of hydrogen peroxide (DOI: 10.1016/j.apsusc.2019.05.205). In general, research on application of an inorganic material for sensing and detection of organic molecules is an extremely complex task and is often based on empirical observations. Model studies at various levels of complexity are expected to better understand the role of electrode material for sensing applications.
Herein, we propose to study and develop an electrochemical model sensor based on cerium oxide film for the detection of commonly used herbicides in agriculture, i.e. glyphosate, glufosinate, bialaphos molecules, etc. Efforts are definitively needed in developing sensitive and selective analytical methods for the implementation of proper technologies for the on line and real time monitoring of herbicides and their remediation in contaminated areas.
Following a bottom-up approach, we propose to combine electrochemical techniques (often used for sensing system development) coupled with surface science techniques to assess activity of cerium oxide electrodes versus herbicide molecules.
Electrochemical measurements will be performed using cyclic voltammetry, chronoamperometry and electrochemiluminescence methods to determine sensitivity, detection limits and linearity of the sensing system. This part will be carried out in close cooperation with Dr. Alessandra Zanut from the Department of Chemical Science, University of Padova, Italy, which has extensive expertise in the electrochemical techniques mentioned above and their application in sensing devices. The electrode surface analysis will be performed by synchrotron radiation based techniques (SRPES, RPES, NEXAFS, etc.) at the Materials Science Beamline of Elettra Sincrotrone, Trieste.
The study will benefit from the classic surface science approach that gives insight on electronic structure changes of the surface that may be responsible for sensor sensitivity. In addition, we will use a robust, reproducible, and affordable technique for preparation of cerium electrodes which has been already developed in our department for potential sensing devices. Based on the results obtained, exploratory experiments will be carried out to determine whether the performance of the sensors (detection limit, linearity, stability) can be improved by changing the morphology of the oxide films.
This project is expected to favour the formation of young researchers and to strengthen ongoing collaborations between Charles University and University of Padova. High-value data and knowledge will be exchanged among universities to optimize the research results and reach important milestones in the use of cerium oxide films for sensing and green technologies.
Supervisor: Mgr. Yurii Yakovlev, Ph.D.
Phasing-in of low-emission technologies requires the development of advanced power sources. Hydrogen proton-exchange fuel cells are considered as one of the main candidates for the electrification of the transportation sector, providing efficient and lightweight power generating systems. However, fuel cell performance relies on catalytically enhanced electrodes with relatively large amounts of expensive platinum. To make fuel cell technology affordable and increase its market share a paradigm shift in catalyst development is required. Thus, a change of local pH to the base one can radically boost oxygen reduction performance, providing significantly cheaper and more durable catalysts. Moreover, the durability of fuel cell components will be improved due to the passivation effect in the alkaline medium. On the other hand, the hydrogen oxidation (HOR) reaction rate on the anode catalyst in an alkaline medium is significantly reduced by comparison to an acidic medium. The lower rate of HOR reaction is exacerbated by the water flooding issue. Therefore, it is necessary to develop catalyst layers that have high HOR activity, yet have little or no use of platinum group metals. Such catalysts will be prepared by both chemical and PVD techniques and analyzed by R/RDE, XPS, TEM, and SEM methods. The most promising materials will be used for fuel cell testing. Alongside with development of novel catalyst materials water and gas transport will be studied and optimized.
Supervisor: RNDr. Peter Kúš, Ph.D.
A water electrolyzer (WE) is an electrochemical cell that converts electrical energy to chemical energy by means of the endergonic reaction 2H2O + electrical energy -> O2 + 2H2. The conversion of electricity to another form of energy and its consequent storage is a very important topic in the context of the utilization of renewable but intermittent energy sources (e.g., sun and wind).
Anode Exchange Membrane Water Electrolyzers present a crucial step in building the Hydrogen economy, as they combine the advantages of Alkaline electrolyzers (non-noble catalysts) and Proton Exchange Membrane Water Electrolyzers (high efficiencies, variability, compact design). Finding a sufficiently active, stable, and non-noble catalyst for the anode and cathode side of the AEM-WE is one of the leading research goals in the field.
The Ni-Fe/Ni-Co alloys etc. have shown remarkable performance for the anodic oxygen evolution reaction, even in pure water – many catalysts work only in the KOH electrolyte. However, the exact understanding of the Ni, Co, and Fe-based catalysts is still missing.
The objective of this dissertation thesis is to build on the prospective results of the Nanomaterials Group, predominantly in the area of novel catalysts for the oxygen evolution reaction. Magnetron sputtered thin-film catalysts, typically with a structure of Ni,Co,Fe/porous sublayer will be studied with emphasis on the stability and activity dependence on morphology and defect density. Layers of various compositions and morphologies will be prepared with the goal of identifying the ideal structural parameters in terms of both durability and activity. Wide arsenal of analytical methods will be available, ranging from electrochemical testing through X-ray photoelectron spectroscopy to electron microscopy. A great focus will be laid on the operando variants of those methods.
Supervisor: Yevheniia Lobko, Ph.D.
Such alternative and eco-friendly energy sources as the anion exchange membrane (AEM) fuel cells and water electrolyzers are very perspective, and comparably cheap. However, the weak point in this technology is a membrane.
The aim of this work is to overcome one of the key limitations of anion exchange membrane, namely water management combined with the improved mechanical and electrochemical performance. The new advanced polymer membranes (stable over a wide temperature range) will be elaborated by the polymer chemical modification and by poly(ionic liquid) incorporation and immobilization inside the polymer matrix. The membrane properties will be evaluated in terms of ion conductivity, mechanical stability and transport properties. The influence of the following factors, i.e. the ionic liquid structure (cation and anion), the mode and conditions of membrane preparation, will be taken into account. Surface-sensitive techniques, specifically scanning electron microscopy (SEM) and atomic force microscopy (AFM), will be utilized to perform a surface morphology analysis of the membranes. This analysis aims to investigate the influence of the surface roughness, homogeneity, and distribution of the polymer heterogeneous blocks or/and ionic liquids on the mechanical and transport properties of the membranes. The X-ray photoelectron spectroscopy (XPS), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), and Raman spectroscopy will be performed to study the surface chemistry and reactions of the AEMs due to provide insights into the chemical and electrochemical behavior of the membrane under operating conditions. Moreover, in-operando XPS in water electrolyzer mode will be used for the investigation of the hydroxide anions’ diffusion in the thin layer of the catalysts, as well as through the membrane. Electrochemical techniques such as electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) can be used to study the membrane's ion conductivity, charge transfer resistance, hydrogen and oxygen cross-overs, and durability in-situ.
By combining these surface studies with bulk membrane characterization techniques (such as thermally gravimetric analysis (TGA), differential scanning calorimetry (DSC), mechanical testing, etc.), it is possible to gain a comprehensive understanding of the AEM's properties and behavior, which can aid in the development of more efficient and durable AEM-based electrochemical systems. Particular attention will be paid on the preparation of membrane electrode assembly using ultrasonic spray-coating and Meyer rod techniques. The overall cyclic performance of the elaborated electrochemical system will be examined in electrolyzer and fuel cell modes.
The main goal of the work is the establishment of the relationship between the structure, morphology, activity, and durability of the AEM membranes in operando in both fuel cells and electrolyzer.
