open positions

PhD fellow in "Multifunctional zeolite materials for processing of platform chemicals and their derivatives"

Project summary:

Due to molecular sieving effect, high adsorption capacity and adjustable chemical composition zeolites are efficient catalysts for a number of processes. However, there is still a lack of synthesis tools for generation of active centers of particular characteristics at particular location in the zeolite frameworks. In addition, there is a growing demand in the catalysts possessing several types of active sites that can be realized in zeolites. The rational design of multifunctional zeolitic materials for catalytic transformation of platform chemicals is an aim of proposed project.

The work will include

application of various synthetic techniques (hydrothermal synthesis, post-synthesis, ADOR) allowing fabrication of materials with desired nature and concentration of active sites;
advanced characterization of designed materials; and
their application for one-pot multistep (cascade) reactions required the presence of several types of active centers (Brønsted and Lewis acid, metal).

The proposed project is focused on the preparation of structurally and chemically diversified zeolites followed by thorough investigation of structure – functionality –activity relationship in a set of useful processes (transformation of furfuryl alcohol/furfural to γ-valerolactone; sucrose isomerization to hydroxymethylfurfural followed by its oxidation to furandicarboxylic acid; condensation of levulinic acid and furfural with further hydrogenation of intermediate product).

PhD fellow in "Selectivity driving parameters in redox reactions catalyzed by Lewis acid zeolites"

Project supervisor: Jan Přech

Project summary:

Zeolites are robust and environmentally friendly heterogeneous catalysts. They contain framework metal ions, which act as Bronsted or Lewis acid sites. In particular, the Lewis acid sites (generated, e.g., by incorporated Ti, Sn, Zr, and Hf ions) catalyze selective redox reactions such as oxidation with peroxides or hydrogen transfer reactions. Type and coordination of the acid sites together with their confinement and surrounding channel environment define the site catalytic properties.

The overarching aim of this PhD project is to find parameters, which define the selectivity in selected redox reactions, use these parameters to drive the selectivity and ultimately induce a stereoselective progress of the reaction.

The project will cover 3 basic tasks:

synthesis of the Lewis acid zeolites, which will include known syntheses optimization to drive type of the present acid sites,
investigation of selected redox reactions in terms of and varying the used conditions and selectivity modifiers, and
characterizing acid site-substrate complexes to get insight in the reaction mechanism particularly in respect to the selectivity modifying parameters.

Of these, task II will be the most important and it will include simple experiments in batch catalytic reactors as well as work with complex microflow catalytic apparatus.

PhD fellow in "Stabilization of metal clusters on the zeolite supports and their assessment by in-situ electron microscopy methods"

Project supervisor: Michal Mazur

Project summary:

Metal nanoparticles immobilized at zeolite supports are important class of heterogenous catalysts for hydrogenation and dehydrogenation, reforming, and water-gas shift reactions. Zeolites, porous elementosilicates, are used to encapsulate metal nanoparticles to improve their stability. Currently, in-situ encapsulation and post-synthesis functionalization are two main synthesis strategies for metal incorporation in zeolites. Zeolites are often prepared as 3D solids; however, some topologies have layered representatives. Direct exfoliation of zeolites into suspension of monolayers has widened the spectrum of novel zeolitic supports for functionalization, thus design of new catalysts.

The main objective of the thesis will be:

preparation of zeolites, including layered precursors;
functionalization of prepared supports with metal clusters;
characterization of prepared materials by advanced, in-situ electron microscopy techniques;
optimizing the synthesis procedure to achieve better stability of prepared catalysts; and
catalytic tests of prepared materials and investigation of metal stability under reaction conditions.

We are looking for motivated students with experience in synthesis and heterogenous catalysis.

The experience in transmission electron microscopy will be an advantage.

PhD fellow in "Synthesis of novel zeolites and their structure determination by advanced electron diffraction"

Project supervisor: Michal Mazur

Zeolites are porous elementosilicates with vast applications in the fields of catalysis, sorption, and ion-exchange. Their advantage lies in properties, such as high adsorption capacity, defined microporosity (resulting in molecular sieving effect), adjustable chemical composition, and possibility for post-synthesis modifications. Conventional synthesis of zeolites uses solvothermal methods that are limited in term of control and design of the process. On the contrary, recently developed ADOR synthesis approach (Assembly, Disassembly, Organization, Reassembly) gives the possibility to design the final products and prepare different type of porous materials by post-synthesis manipulations (using 2D zeolite precursors) or removal of specific building units from the parent material. Design and synthesis of novel zeolitic materials and their advanced characterization by electron microscopy and electron diffraction methods are general aims of proposed PhD thesis. The synthesized materials will be investigated for their potential use e.g. in catalysis.

The PhD work will include:

the application of established synthetic techniques (e.g. solvothermal synthesis, ADOR approach, swelling, pillaring, and functionalization,
development of novel synthesis strategies, and
characterization of synthesized material by electron microscopy and diffraction methods (including novel techniques like Continuous Rotation Electron Diffraction (cRED).

The PhD work will result in preparation of new zeolitic materials and their structure determination by advanced characterization methods.

The experience in electron microscopy and zeolite synthesis will be an advantage for the potential candidate.

PhD fellow in "Understanding active sites of zeolite catalysts"

Project supervisor: Mariya Shamzhy

Project summary:

Heterogeneous single-site catalysts are the latest generation materials enabling to maximize the profit and minimize the waste-related issues during production of important chemicals. Although zeolites have been the key industrial catalysts for several decades, development of their single-site representatives as well as analytical techniques for detailed characterization of their active sites are at the very beginning of their inception. Therefore, screening, optimization and implementation of ex situ and in situ methods allowing to distinguish and comprehensively describe the potential active centers of different confinement and local geometry are in great demand. This is what we would like to explore further together with you, the successful applicant.

This work will focus on establishing diagnostic spectroscopic features of metal centers located in isolated or paired configurations in specific T-sites of a zeolite framework within the pores/cages of defined size. For that, a combination of solid state NMR and FTIR spectroscopies of adsorbed probe molecules will be complemented by structure refinement against diffraction data.

PhD fellow in Rational synthesis of zeolitic materials and their characterization by advanced electron microscopy methods

Project supervisor: Michal Mazur

Project summary

Zeolites are among the most useful materials in catalysis, sorption and ion-exchange. It is due to their properties i.e. high adsorption capacity, defined microporosity (resulting in molecular sieving effect), adjustable chemical composition, and possibility for post-synthesis modifications. Conventional synthesis of zeolites is performed by solvothermal methods that are limited in term of control and design of the process. On the other hand, recently developed ADOR synthesis approach (Assembly, Disassembly, Organization, Reassembly) utilizing the 2 dimensional (2D) layered zeolite precursors gives the possibility to design the final product and prepare different type of porous materials by post-synthesis manipulations. The rational design of novel zeolitic materials and their characterization by advanced electron microscopy methods are general aims of proposed PhD thesis. The synthesized materials will be investigated for their potential use e.g. in catalysis, especially for acid-catalysed reactions. The PhD work will include: 1) the application of established synthetic techniques (e.g. solvothermal synthesis, ADOR approach, swelling, pillaring, and functionalization, 2) development of novel synthesis strategies, and 3) characterization of synthesized material by electron microscopy and diffraction methods (including novel techniques like Rotation Electron Diffraction (RED). The PhD work should result in preparation of new zeolitic materials and their better understanding by use of advanced characterization techniques.

Five relevant publications of the research group

Wieslaw J. Roth, Petr Nachtigall, Russell E. Morriss, Paul S. Wheatley, Valerie Seymour, Sharon E. Ashbrook, Pavla Chlubná, Lukáš Grajciar, Miroslav Položij, Zrnošt Zukal, Oleksiy Shvets, Jiří Čejka, "A family of complex zeolites with controlled pore size prepared through a 'top down'method", Nature Chemistry, 5 (2013) 628.

Pavla Eliášová, Maksym Opanasenko, Paul Wheatley, Mariya Shamzhy, Michal Mazur, Petr Nachtigall, Wieslaw J. Roth, Russell E. Morris, Jiří Čejka, “The ADOR mechanism for the synthesis of new zeolites”, Chemistry Society Reviews, 44 (2015) 7177.

M. Mazur, P. S. Wheatley, M. Navarro, W. R. Roth, M. Polozij, A. Mayoral, P. Eliasova, P. Nachtigall, J. Cejka, R. E. Morris, “Synthesis of ‘unfeasible’zeolites”, Nature Chemistry, 8 (2016) 58-62.

M. Mazur, V. Kasneryk, J. Přech, F. Brivio, C. Ochoa-Hernández, A. Mayoral, M. Kubů and J. Čejka, “Zeolite framework functionalisation by tuneable incorporation of various metals into the IPC-2 zeolite”, Inorganic Chemistry Frontiers, 2018, 5, 2746-2755.

S. E. Henkelis, S. A. Morris, M. Mazur, P. S. Wheatley, L. N. McHugh and R. E. Morris, “Monitoring the assembly–disassembly–organisation–reassembly process of germanosilicate UTL through in situ pair distribution function analysis”, Journal of Materials Chemistry A, 2018, 6, 17011-17018.

Current research grants of the group

EXPRO GAČR (19-27551X)

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PhD fellow in Rational design of hierarchical zeolites for the synthesis of fine chemicals

Project supervisor: Maksym Opanasenko

Project summary

Due to such useful characteristics as molecular sieving effect, high adsorption capacity, adjustable chemical composition zeolites are efficient catalysts of a number of large-scale processes. At the same time, despite showing unique and extremely useful properties, micropores impose restrictions on the mass transport of bulky reactants limiting the use of conventional zeolites in fine chemical or pharmaceutical synthetic applications. Last decade has brought a number of different strategies to accomplish the synthesis of zeolites with additional mesoporosity, i.e. hierarchical zeolites. The advantageous features of hierarchical zeolites (e.g. multilevel porosity, high concentration of acid sites with tunable strength) can be used to further extend the potential of zeolites to new applications in catalysis. The rational design of novel hierarchical (micro-mesoporous) zeolitic materials for catalytic applications is a general aim of proposed PhD thesis. The work will include both 1) the application of well-known synthetic techniques (e.g. removing of framework atoms) allowing fabrication hierarchical materials to novel objects (e.g. Ge-containing zeolites) and 2) further development of innovative approaches invented during last decade. This shall result in the preparation of a broad range of structurally and chemically diversified hierarchical zeolites followed by thorough investigation of structure – acidity – catalytic activity relationship in a set of acid-catalyzed reactions.

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PhD fellow in Hybrid Nanostructures Based on Polymer-Ions Interaction

Project supervisor: Pavel Matějíček

Project summary

Highly charged molecules and nano-assemblies serve as unique building blocks in nanochemistry. Bulky and multivalent ions are known to readily condense on polyelectrolyte chains or brushes. Such ions are therefore capable to co-assemble with double-hydrophilic block copolymers into core/shell nanoparticles. It brings new function into the system and also introduces sensitivity to external stimuli, both depending on the nature of the charged specie. Besides co-assembling with polymers, a structure of hydration shell and a propensity of ions to specific interactions are interesting per se. It can lead to a complex solution behavior and the corresponding formation of nano-aggregates.

Skills in nanochemistry and synthetic chemistry are welcomed!

Three relevant publications of the research group

Fernandez-Alvarez R., Dordovic V., Uchman M., Matejicek P.: Amphiphiles without Head-and-Tail Design: Nanostructures Based on the Self-Assembly of Anionic Boron Cluster Compounds. Langmuir 2018, 34, 3541-3554.

Dordovic V., Uchman M., Reza M., Ruokolainen J., Zhigunov, A., Ivankov O.I., Matejicek P.: Cation-sensitive compartmentalization in metallacarborane containing polymer nanoparticles. RSC Advances 2016, 6, 9684–9892.

Uchman M., Dordovic V, Tosner Z., Matejicek P.; Classical Amphiphilic Behavior of Nonclassical Amphiphiles: A Comparison of Metallacarborane Self-Assembly with SDS Micellization. Angewandte Chemie-International Edition 2015, 54, 14113–14117.

Current research grants of the group

Czech Science Foundation grants: 17-00648S “Chaotrope, hydrotrope or surfactant? Anionic boron cluster compounds in water and in complexes with polymers” ends in 2019, and 19-13458S “Nanomaterials based on co-assembly of triblock copolymers with macroions and other atypical ions” 2019-2021.

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PhD fellow in Sugar and pH-responsive multicompartment nano-assemblies for dual-drug solubilization and delivery

Project supervisor: Mariusz Uchman

Project summary

The concept of Multicompartment Micelles (MCMs), i. e., self-assembled aggregates with moieties of different chemical properties, that mimic biological molecules such as proteins was derived by Prof. H. Ringsdorf almost twenty years ago and theoretically described by de Gennes. Figure 1 represents a rather futuristic view of multifunctional smart nanoparticles that possess various sub-domains and functions that coexist and perform in close proximity without mutual interference or with controlled interactions, as it works in nature. The self-assembly process of amphiphilic polymers in water is an attractive platform for preparation of such multi-compartment nanoparticles, due to the mutual incopatibilities of the polymers involved.

The overall goal of this proposal is to gain new information on nanostructure and dynamics of newly designed MCMs based on biodegradable and biocompatible ABC triblock terpolymers. The most often used ABC terpolymers in the research of the MCMs consist of highly incompatible hydrocarbon and fluorocarbon blocks that ensure compartmentalization of nanoparticles, however the lack of responsive functional groups to biologically relevant environment is the main drawback of such MCMs. Much less is known about MCMs that contains hydrocarbon blocks only and boronic acid derivatives. This is why we will focus on synthesis and self-assembly of new ABC triblock terpolymers having at least one boronic acids (bezoxaborol or Wulff-type boronic acids) containing block combined with a hydrophilic and hydrophobic one. By incorporating boronic acids, amphiphilic nanoparticles can be prepared that reversibly bind to 1,2- or 1,3- diols and catechol-containing molecules as well as they are responsive to subtle changes in solution pH (relevant in cancer therapy) and saccharide concentration (relevant for diabetes - related applications). In addition the hydrophobic core forming block will accommodate hydrophobic drugs or fluorophores. The neutral hydrophilic block forms the stabilizing corona of the micelles.

The subdivided core of MCMs serves as a microcontainer for a variety of different active agents. This is why the next goal is to broaden the knowledge on selective solubilization of aromatic compounds (drugs) and their sequential release from MCMs to achieve a synergistic antitumor effect and improve the therapeutic index. Fluorescence techniques will allow us to provide information on local physicochemical properties like micropolarity, microviscosity, local electrostatic potential or accessibility of the fluorophore’s (drugs) neighborhood by certain molecules like quenchers.

Profile of an ideal candidate

Good knowledge of English (FCE equivalent or better)

Background in polymer chemistry and/or phenylboronic acid synthesis and characterization

Experience with scattering techniques, drug solubilisation and delivery

Publications

Glucose-Responsive Hybrid Nanoassennblies in Aqueous Solutions: Ordered Phenylboronic Acid within Intermixed Poly(4-hydroxystyrene)-block-poly(ethylene oxide) Block Copolymer By: Matuszewska, Alicja; Uchman, Mariusz; Adamczyk-Wozniak, Agnieszka; et al. BIOMACROMOLECULES
- Volume: 16 Issue: 12 Pages: 3731-3739 Published: DEC 2015

Preparation of lactic acid- and glucose-responsive poly(epsilon-caprolactone)-b-poly(ethylene oxide) block copolymer micelles using phenylboronic ester as a sensitive block linkage By: Vrbata, David; Uchman, Mariusz NANOSCALE
- Volume: 10 Issue: 18 Pages: 8428-8442 Published: MAY 14 2018

Current research grants of the group

Czech Science Foundation grunt no. 17-00289Y: Sugar and pH-responsive multicompartment nano-assemblies for controlled drug solubilization and release

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PhD fellow in Theoretical studies of endohedral fullerenes

Project supervisor: Filip Uhlík

Endohedral fullerenes, i.e. cage-like hollow carbon molecules with an atom or a small molecule trapped inside, are fascinating species with unusual properties attractive for applications. With Gd atom inside they can serve as MRI contrast agents, with a radioactive metal as radiotracers, with N atom as q-bits in quantum computers, with metal nitrides as materials for organic solar cells, etc. The applications, however, are hindered by high costs of preparation of these compounds and too many possible combinations of fullerenes and encapsulated species. For these reasons the theoretical predictions can be particularly valuable.

The goal of this Ph.D. project is to obtain structural, spectral, thermodynamic and kinetic predictions by standard methods of quantum chemistry and statistical thermodynamics for several endohedrals, namely metallofullerenes studied experimentally by partner research groups, e.g., DOI: 10.1002/anie.201604121. Going beyond the standard calculations is also possible for an enthusiastic student, e.g. calculation of an inherently quantum motion of the encapsulated species by path-integral Monte Carlo methods (from the calculation of the potential to the simulational methodology).

Profile of an ideal candidate: M.Sc. or equivalent degree in Chemistry, Physics, Material Science or a related field (required), working communication skills in English, background in quantum chemistry, statistical thermodynamics and Unix-like operating systems.

PhD fellow in Modeling of weak polyelectrolytes interacting with multivalent ions.

Project supervisor: Peter Košovan

Association of weak polyelectrolytes can be controlled by the variable pH-sensitive ionization of weak acid and base groups. Encapsulation of multivalent molecules in polyelectrolyte-based systems can be controlled by the same means. Release of the cargo molecules can be then triggered by a change of pH. For example, multivalent porphyrin derivatives can be encapsulated in polyelectrolyte micelles or interpolyeletrolyte complexes. Using coarse-grained molecular simulations, we will predict electrostatically controlled interactions in theses systems. The simulations will be used to guide experimental optimization of self-assembled polyelectrolyte systems investigated by the experimental team within the Soft Matter research group. The ultimate goal is to achieve rational design of these systems using a combination of simulations and experiments.

The prospective candidate should perform coarse-grained simulations of polyelectrolytes and interpolyelectrolyte complexes interacting with multivalent ions, and focused on ionization equilibria. He/she will use the open source simulation package Espresso [www.espressomd.org], and will implement data analysis routines for the specific problems investigated here. A contribution to development of the simulation package is also foreseen.

Current research grants of the group

Czech Science Foundation grant 19-10429S

Profile of an ideal candidate

MSc. or equivalent in Chemistry, Physics or a related field (required), good knowledge of English, background in Statistical Mechanics, Soft Matter, and Polymer Science. Experience with molecular simulations, programming and Linux.

Apply to the project

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Open Positions

Open postdoc and PhD positions

PhD fellow in "Multifunctional zeolite materials for processing of platform chemicals and their derivatives"

PhD fellow in "Selectivity driving parameters in redox reactions catalyzed by Lewis acid zeolites"

PhD fellow in "Stabilization of metal clusters on the zeolite supports and their assessment by in-situ electron microscopy methods"

PhD fellow in "Synthesis of novel zeolites and their structure determination by advanced electron diffraction"

PhD fellow in "Understanding active sites of zeolite catalysts"

Assistant Professor position in experimental Physical chemistry

Postdoc position in Catalysis

Postdoc position in Synthesis of two-dimensional materials

Postdoc position in Synthesis of zeolites

PhD fellow in Rational synthesis of zeolitic materials and their characterization by advanced electron microscopy methods

Project summary

PhD fellow in Rational design of hierarchical zeolites for the synthesis of fine chemicals

Project summary

PhD fellow in Hybrid Nanostructures Based on Polymer-Ions Interaction

Project summary

PhD fellow in Operando computational modelling of materials

Project summary

PhD fellow in Sugar and pH-responsive multicompartment nano-assemblies for dual-drug solubilization and delivery

Project summary

PhD fellow in Theoretical studies of endohedral fullerenes

PhD fellow in Modeling of weak polyelectrolytes interacting with multivalent ions.

Postdoc in Association of Block-Copolymers Containing Weak Polyelectrolytes