Due to the current situation (COVID-19) access to the laboratories, and in fact the entire David de Wied & Vening Meinesz buildings, is strictly limited until further notice.
We can therefore only accept a limited number of new MSc or BSc projects; applications are handled on a first-come-first-serve basis. Please make sure to fill in and submit your request via the online form linked to here.
Supervisors: Kordula Schnabl, Laurens Mandemaker, Christia Jabbour
Title: Synthesis and Characterization of UiO-67/Chitosan composites for CO2 hydrogenation
Chitosan (CS) is a bio-derived polymer, which is obtained from its natural counterpart chitin out of the exoskeleton of marine crustaceans, e.g. shrimps, lobster and crabs1. It is soluble in aqueous acids and finds applications in pharmaceutical industries due to its antibacterial properties2, but its use could be extended towards catalytic processes, where it would function for example as a strong and stable carrier material for several catalysts or as a composite binder. Due to its high accessible surface area (2500 m2 g-1)3 and porosity, the metal-organic framework (MOF) UiO-67 can be such an advantageous catalyst for multiple reactions4. It is known that Pt-induced UiO-67 catalysts catalyze CO2 hydrogenation reactions2, recycling the thermodynamically stable CO2 into more valuable products while reducing it in our atmosphere as a key contributor to global warming5.
We successfully synthesized CS/UiO-67 composites, however further work needs to be done to unravel the details of this potential CO2 hydrogenation catalyst. Therefore, the aim is to synthesize these composites in different shapes such as beads6 and films as well as to compare those to the synthesized powder7, and characterize their molecular structure as well as their catalytic activity using techniques such as scanning electron microscopy (SEM), in-situ infrared spectroscopy (IR), and sorption measurements.
1. Rinaudo, M. Chitin and chitosan: Properties and applications. Polym. Sci. 31, 603–632 (2006).
2. Younes, I. & Rinaudo, M. Chitin and chitosan preparation from marine sources. Structure, properties and applications. Drugs 13, 1133–1174 (2015).
3. Katz, M. J. et al. A facile synthesis of UiO-66, UiO-67 and their derivatives. Commun. 49, 9449– 9451 (2013).
4. Rivera-torrente, M. et al. Spectroscopy, microscopy, diffraction and scattering of archetypal MOFs: formation, metal sites in catalysis and thin films. chem soc Rev (2020). doi:10.1039/d0cs00635a
5. Gutterød, E. S. et al. CO2 Hydrogenation over Pt-Containing UiO-67 Zr-MOFs – The Base Case. Eng. Chem. Res. 56, 13206–13218 (2017).
6. Liu, L., Yang, W., Gu, D., Zhao, X. & Pan, Q. In situ Preparation of Chitosan/ZIF-8 Composite Beads for Highly Efficient Removal of U(VI). Chem. 7, 1–10 (2019).
7. Wang, K., Tao, X., Xu, J. & Yin, N. Novel chitosan-MOF composite adsorbent for the removal of heavy metal ions. Lett. 45, 1365–1368 (2016).
Supervisor: Dmitrii Osadchii, Eline Hutter
Title: Stabilizing lead-free perovskites for photocatalytic degradation of air pollutants
In recent years metal halide perovskites (MHPs) have attracted significant attention for a variety of optoelectronic applications, including solar cells, lasers, and LEDs, due to tunability of their bandgap, high light absorption and photoluminescent properties, long carrier diffusion length, and relative inexpensiveness of their synthesis. New generation of double metal halide perovskites, such as Cs2AgBiBr6 (CABB), are particularly interesting for practical utilization as they do not contain lead and other highly toxic elements. Properties of CABB and other MHPs make them promising for photocatalysis, and their applicability has already been demonstrated in photocatalytic reduction of CO2, oxidation of pollutants, and water splitting reactions. However, irreversible degradation of MHPs in polar solvents and even in wet air strongly limits their suitability for practical use.
To combat this challenge, in this MSc project we are aiming to develop approaches for stabilization of CABB without compromising its photocatalytic properties. The chosen strategy implies encapsulation of perovskite particles in shells of metal organic frameworks (MOFs) – porous materials, constructed of metal clusters linked by organic ligands. The choice of metal and organic linker not only allows to control the porosity and stability of MOF, but also can enhance the charge separation and transfer properties of the photocatalyst. Within this project the student will have a chance to try different approaches for the synthesis of perovskite nanoparticles and for their encapsulation with MOFs, as well as to learn techniques for characterization of their optoelectronic properties and to test them in photocatalytic degradation of air pollutants.