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 starting from Thursday March 19 until further notice.
We can therefore not accept new MSc or BSc projects before late summer, but definitely not before end of August.
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.
Supervisor: Matteo Monai
Title: Model Metal Catalysts Preparation by Spark Ablation for Shell-Isolated Nanoparticle Surface Enhanced Raman Spectroscopy (SHINERS)
Short project description: Shell-Isolated Nanoparticle Enhanced Raman Spectroscopy (SHINERS) is an emerging technique to study surface reactions on solid catalysts.1 Spark Ablation (SA) can open up the field of SHINERS to industrially relevant catalysts (e.g. Ni-based), producing size-selected and unprotected nanoparticles that can be deposited on flat surfaces.2,3 This project will develop robust protocols for SA to prepare (for the first time) size-selected Ni nanoparticles supported on Au@SiO2 (or TiO2) for in situ SHINERS studies. Structure sensitive probe reactions will be targeted to give proof-of-concept of the impact of the proposed preparation methodology. The results will shed new lights on structure sensitivity in key catalytic reactions and pave the way to expand the use of SA in heterogeneous catalysts preparation.
 T. Hartman, C. Wondergem and B. M. Weckhuysen, ChemPhysChem, 2018, 19, 2461–2467.
 C. S. Wondergem, J. J. G. Kromwijk, M. Slagter, W. L. Vrijburg, E. J. M. Hensen, M. Monai, C. Vogt and B. M. Weckhuysen, ChemPhysChem, 2020, 21, 625–632.
 T. Pfeiffer, P. Kedia, M. Messing, M. Valvo and A. Schmidt-Ott, Materials (Basel)., 2015, 8, 1027–1042.