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.
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: Longfei Wu, Ward van der Stam
Title: Revealing Interphase Miscibility Between Cu and Ag for Electrochemical CO2 Reduction
Valorization of CO2 by electrocatalytic method to value-added fuels and chemicals has emerged as a promising approach to mitigate the increasing CO2 emission and reach a carbon-neutral society. A lot of efforts have been devoted to optimization of the electrocatalyst efficiency, selectivity and stability. Among the various catalysts, Cu is the only metal that can catalyze the electrochemical reduction of CO2 to multi-carbon fuels. However, it remains challenging to tune the selectivity of Cu catalysts towards a specific product, which greatly limits its industrial application. Composition tuning of Cu catalysts by creating alloys or heterostructures with other metals has been reported as an efficient approach to tune the selectivity of Cu-based CO2 reduction electrocatalysts. Cu-Ag bimetallic system has attracted a lot of attention as it couples one metal (Ag) that has a high selectivity to CO and the other metal (Cu) with the capability to further reduce CO. Interestingly, our recent findings indicate that binary Cu and Ag nanoparticle electrodes can be stabilized during electrochemical CO2 reduction (CO2RR).
Within this MSc project, we intend to investigate the stability and interface miscibility between Cu and Ag during CO2RR with advanced characterization tools such as in situ X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), scanning electron microscopy (SEM), and CO2RR activity measurements. Specifically, the student will try different approaches to prepare Cu-Ag bimetallic electrodes, such as electrodeposition or drop-casting of colloidal Cu and Ag nanoparticles, or prepare bimetallic Cu-Ag heterostructures or alloys through various synthesis methods. He or she will also have opportunities to learn advanced characterization techniques, e.g. in situ XRD, SEM.
 Nitopi, S.;Bertheussen, E.; Scott, S. B.; Liu, X.; Engstfeld, A. K.; Horch, S.; Seger, B.; Stephens, I. E. L.; Chan, K.; Hahn, C.; Norskov, J. K.; Jaramillo, T. F.; Chorkendorff, I., Progress and Perspectives of Electrochemical CO2 Reduction on Copper in Aqueous Electrolyte. Chem Rev 2019, 119, 7610–7672.
 Higgins, D.;Landers, A. T.; Ji, Y.; Nitopi, S.; Morales-Guio, C. G.; Wang, L.; Chan, K.; Hahn, C.; Jaramillo, T. F., Guiding Electrochemical Carbon Dioxide Reduction toward Carbonyls Using Copper Silver Thin Films with Interphase Miscibility. ACS Energy Lett. 2018, 3 (12), 2947-2955.