Qualifications

BACHELOR-, MASTER THESES AND PRACTICAL COURSES

• Preparation of transition metal catalysts by synthesis of Prussian Blue Analogues

Topics Bachelor, Advanced and Master Theses / Supervised by M.Sc. Stephan Feser

On the one hand, catalysts require a high specific surface area in order to provide as many active centres as possible for the reaction; on the other hand, an unhindered flow into and out of the pores must be ensured by meso- and macropores. In addition, spinels are to be specifically produced, which are then to be used as solid catalysts in CO oxidation.

Prussian blue and its analogues, which are synthesised by co-precipitation, serve as templates. The aim is to generate as large a uniform pore system as possible, which is then to be partially protected during the subsequent calcination to mixed metal oxides/spinels. This is done by using saturated salt solutions during washing.

The variations of the parameters during the synthesis are almost unlimited, so that a variety of routes are to be tried and analysed. Subsequently, the samples will be tested in the catalytic CO oxidation. For master's students, analyses after oxidation could then follow in order to comprehensively characterise the catalyst.

Analyses will be carried out via mercury intrusion, nitrogen low-temperature sorption, scanning electron microscopy, XRD, ICP-OES, ...

• Synthesis of highly porous silica xerogels as thermal insulation material

Topics Advanced and Master Theses | Supervised by M.Sc. Kai Müller

In order to reduce energy consumption in Germany and worldwide, effective materials for thermal insulation must be developed. With their help, the required heating energy can be significantly reduced.

One of the most promising materials is silica aerogels, which are produced based on the sol-gel process. These highly porous gels have extremely low thermal conductivities, but are only used to a limited extent due to the currently still high production costs and low stability. Silica xerogels, on the other hand, show improved stability and significantly lower manufacturing costs, although the thermal conductivity of the material increases.

Within the framework of a master's thesis, the properties of the xerogels are to be optimised in the direction of lower thermal conductivities with the same stability.

• Synthesis of carbon-silica composites

Topics Bachelor, Advanced and Master Theses / Supervised by M.Sc. Bettina Lilli

In the course of Green Chemistry, the sustainable synthesis of adsorbents for the removal of pollutants from water bodies is becoming more and more important. Agricultural residues in particular are taking on an increasingly important role here. Within this topic, carbon-silica composites are to be produced from rice husks via various synthesis steps. The variation of different parameters will be investigated.

Nitrogen sorption, water glass analysis, CHN elemental analysis, optical emission spectrometry with inductively coupled plasma and scanning electron microscopy are mainly used for characterisation.

• Synthesis of water-stable porous boron nitride by leaching

Topics regarding Bachelor and Advanced Thesis / Supervised by M.Sc. Tim Jähnichen

Unlike many other adsorbents, boron nitride has high thermal and chemical stability, and therefore can be used sustainably and regenerated easily. Due to its special dipolar properties, the material has a high affinity for adsorption of metal ions, antibiotics, organic solvents and greenhouse gases. It can also be used as a hydrogen storage medium. However, the material has low stability to water, so its applications are severely limited.

Through preliminary work, the synthesis of water vapor-stable boron nitride was achieved. Unfortunately, these materials did not show complete stability toward liquid water. In order to further increase the stability of porous boron nitrides, the method of postsynthetic leaching will be applied. Within the scope of this work, optimal parameters for this post-treatment are to be found in order to obtain a material that is as porous and stable as possible. The characterization of the materials takes place primarily via mercury intrusion, nitrogen sorption, scanning electron microscopy, X-ray diffraction, thermogravimetry, XPS and infrared spectroscopy.

 

• Porous Glasses as Transdermal Drug Delivery Systems (TDDS)

Topics Bachelor, Advanced and Master Theses / Supervised by M.Sc. Theresa Paul

Porous glass is to be studied as a potential transdermal delivery systems for various drugs. Due to their tunable pore size and volume as well as their large surface area, porous glasses present advantageous and novel properties for these applications.
Student works are possible in our research group, where material science aspects are studied. Possible student works include functionalization of the glass surface, modification of the pore structure and the development as well as improvement of methods to obtain ultra-thin and flexible glass membranes. (BA, MA, Vertiefer possible)
Students interested in the construction and automation of a model plant-system to stretch form porous glasses are also welcome to apply. Basic knowledge or interest in LabView, coding and engineering are preferred. (MA, Vertiefer students only)
It is further possible to do student works with our research partners in the pharmacological department of the University of Leipzig (Rudolf-Boehm-Institute for pharmacology and toxicology). Thereby drug loading and release kinetics are investigated via HPLC mass spectrometry. Furthermore, biocompatibility, adhesion to skin and toxic effects of the innovative drug carrier are examined. (Vertiefer, MA or teaching students)
Student works are possible in English and German.

• Development of porous, high-temperature stable CeO₂ supports for sustainable CH₄ production from greenhouse gases

Topics regarding Bachelor, Advanced and Master Thesis / Supervised by M.Sc. Tim Jähnichen

Due to depleting oil and natural gas reserves sustainable production of valuable fuels such as synthetic natural gas from CO and CO₂ (SEG) or bioethanol from sugar- or starch-containing plants is becoming increasingly important. If CO/CO₂ from the atmosphere or renewable resources is used for sustainable SEG synthesis, greenhouse gases are reduced and global warming is counteracted. Low-cost supported nickel-based catalysts possess high selectivity and activity in this hydrogenation reaction. For these catalysts, it has been shown that the support (Al₂O₃, CeO₂, ZrO₂, etc.) not only determines the textural properties and dispersion of the active phase, but also plays a key role in CO₂ activation. Ceria has excellent redox properties (Ce³⁺/Ce⁴⁺ redox couple) and also exhibits high oxygen storage capacity. Accordingly, ceria supports possess a large amount of oxygen vacancies with intermediate basicity compared to other support materials, which promote CO₂ activation dissociation and metal-support interaction.

The following tasks will be pursued in the context of preparing an open-pore ceria support material from phase-separated glasses for SEG synthesis from atmospheres CO/CO₂:

• Preparation and characterization of homogeneous Na₂O-B₂O₃-CeO₂ glasses.
• Generation of uniform phase separation to adjust porosity.
• Obtaining a comprehensive understanding of phase transformation during heat treatment and extraction
• CO/CO₂ adsorption studies concerning the influence of pore texture as well as phase composition