Currently the following calls for MSc projects are open. If you are interested submit your request via the online form linked to here. First please consult our page information for students.
Supervisor(s): Nicolette Maaskant
Title: The mechanism behind photo-assisted catalysis for CO2 hydrogenation over cobalt based catalysts.
Please note: The project is only available as a fulltime project and needs to start in the second period at the latest, due to availability of supervisor
Description: To create a circular CO2 economy and a more sustainable society efficient CO2 valorisation is necessary. CO2 hydrogenation is an established strategy for converting CO2 into base chemicals, such as hydrocarbons or alcohols. However, typical base metal catalysts for CO2hydrogenation suffer from low activity.1 One approach for improvement is the use of light during thermal catalysis to improve the catalytic process (i.e. photo-assisted catalysis).2 Various photo-assisted reaction pathways are reported, e.g. plasmon band excitation, photothermal effects, excitation of adsorbates and excitation of valence band electrons to the conduction band (Figure 1A).2–4 To fully take advantage of photo-assisted catalysis, a thorough understanding of the interplay between the photons, electrons and the reaction mechanism is needed.
To investigate photo-assisted catalysis, we use catalysts with cobalt nanoparticles supported on TiO2 as it is known to be active for CO2 hydrogenation.5 Using a variety of techniques, like operando infrared spectroscopy and x-ray absorption spectroscopy we have observed that CO2conversion, the reaction intermediates and the oxidation state of cobalt are influenced by shining light on the catalyst during reaction. To further understand the underlying mechanisms of these effects, we want to extend this investigation to different support materials (e.g. silica which is photochemically inert). This will give us more information about the role of the support in the photo-assisted CO2 hydrogenation. During this project you will synthesize some catalyst materials and thoroughly investigate their (catalytic) properties under the influence of light. Techniques that you will use include UV-vis spectroscopy, (operando) infrared spectroscopy and characterisation techniques (e.g. XRD).
1. Vogt, C., Monai, M., Kramer, G. J. & Weckhuysen, B. M. The renaissance of the Sabatier reaction and its applications on Earth and in space. Nat. Catal. 2, 188–197 (2019).
2. Kim, C. et al. Energy-efficient CO2 hydrogenation with fast response using photoexcitation of CO2 adsorbed on metal catalysts. Nat. Commun. 9, 3027 (2018).
3. Xie, B. et al. Synergistic ultraviolet and visible light photo-activation enables intensified low-temperature methanol synthesis over copper/zinc oxide/alumina. Nat. Commun. 11, 1615 (2020).
4. Tan, T. H. et al. Unlocking the potential of the formate pathway in the photo-assisted Sabatier reaction. Nat. Catal. 3, 1034–1043 (2020).
5. Have, I. C. ten et al. Uncovering the reaction mechanism behind CoO as active phase for CO2 hydrogenation. Nat. Commun. 13, 342 (2022).
Supervisor(s): Christia Jabbour, Jennifer Hartong (IRAS) & Laurens Mandemaker
Title: Detection and Characterization of Micro- and Nanoplastics in Powder, Human and Cow milk
Description: In recent years, there has been a growing interest of research dedicated to understanding the potential impacts of micro- and nanoplastics (MNPs) on early-life human health. Ingestion is considered one of the most dominant routes of MNP exposure in humans. Considering the intake of milk of Dutch citizens (257 kg cow milk per capita in 2021), milk and milk products could contribute significantly to MNP exposure and possibly bioaccumulation in humans.
In this proposed research project, samples of human milk, infant formula and cow milk will be collected and analyzed for the presence of MNPs. This experimental procedure involves a degradation process (digestion) which facilitates the removal of naturally occurring fat and proteins present in the milk thereby enabling their isolation from NPs. The digested milk will go through a filtration process after which the MNPs and the residues will be imaged with Scanning Electron Microscopy – Energy Dispersive X-ray analysis (SEM-EDX). The chemical nature and identity of the particles will be assessed using Raman and/or infrared micro-spectroscopy. The products will also be tested with Pyrolysis–Gas Chromatography–Mass Spectrometry (Py-GC MS), which is an analytical technique wherein the sample undergoes heating to decomposition, generating smaller molecules that are subsequently separated via gas chromatography and identified through mass spectrometry. After optimizing the digestion, filtration and detection methods, MNPs present in the milk samples will be determined. This research will yield crucial insights into the amounts and type of MNPs found in milk supply.