Title: Can magnetic manipulation of FeS growth change its catalytic properties?
Description: The need for alternative feedstocks to conventional fossil fuels have put the development of carbon capture, storage and, in particular, utilisation technologies firmly on the scientific and political agenda. Although the catalytic potential of Fe-S nanoparticles is clear from their electronic make-up, production of iron sulphides is complicated and time consuming. However, iron sulphides have surface specific magnetic properties that may influence their behaviour. As surface reactivity is a key parameter for the nucleation and growth of minerals, this means that we may be able to manipulate these phenomena using magnetic fields to optimise iron sulphide growth for catalysis. In this multi-disciplinary project, the group of Helen King from the Department of Geosciences is starting to grow Fe-sulphides in the presence of different magnetic field strengths, while the MSc student in the ICC group will then examine whether this treatment can change the catalytic projects of the FeS particles.
Supervisor(s): Sebastian Rejman, Ina Vollmer
Title: Understanding the Effect of Acidity and Pore Structure in Catalytic Cracking of Polyolefins
Description:The majority of the plastic waste produced worldwide ends up either in a landfill, or is incinerated. Only 12% is recycled, and with current mechanical recycling technology, the resulting recycled plastic is often of significantly lower quality than the original virgin material. Chemical recycling is an emerging technology that aims at converting plastic waste back into chemical building blocks that can be then converted into a variety of products using existing chemical infrastructure. Some approaches are already applied commercially: Pyrolysis of polyolefins yields a mixture of liquid hydrocarbons that can be fed into a steam cracker.1 Using a catalyst in this process allows to lower the energy requirements of the process, and can shift the product distribution towards more valuable products like aromatics.2 Many catalyst properties influence the reaction, e.g. Lewis and Brønsted acidity, pore structure and metal loading. In order to design novel catalyst for polyolefin cracking, the role of these effects must be understood. The goal of this thesis is to understand how acidity or pore structure of the catalyst affects activity and selectivity of the reaction, building upon prior research in our group.
Requirements: Initial experience with programming (e.g. Python or Matlab), interest in catalysis and polymer chemistry.
Earliest possible start: November 2022
1. Vollmer, I. et al. Beyond Mechanical Recycling: Giving New Life to Plastic Waste. Angew. Chemie – Int. Ed. 59, 15402–15423 (2020).
2. Vollmer, I., Jenks, M. J. F., González, R. M., Meirer, F. & Weckhuysen, B. M. Plastic Waste Conversion over a Refinery Waste Catalyst. Angew. Chemie Int. Ed. 60, 16101 (2021).
Supervisor(s): Bram Kappé
Title: Colloidal Ni nanoparticles on various supports as catalysts to study structure sensitivity in CO2 hydrogenation
Description: Most catalytic reactions are structure sensitive, which means that the surface atoms of a supported metal catalyst differ in activity. The specific activity of surface atoms depends nanoparticle shape, size and type of support. To study these effects monodisperse nanoparticles of several sizes are required. We have recently developed a novel size-tunable synthesis procedure for small, monodisperse colloidal Ni nanoparticles. In this project these Ni particles will be deposited on several different supports. The resulting catalysts will be tested for CO2 hydrogenation using operando IR, allowing simultaneous study of the activity and reaction mechanism. This will provide unique opportunity to systematically study the metal-support sites where the CO2 reaction is thought to take place. In this project, you will learn how to perform inert synthesis using a Schlenk line and glovebox, and become proficient in TEM, XRD and operando spectroscopy such as FT-IR.
Supervisor(s): Xinwei Ye, Pieter Bruijnincx (OCC) and Bert Weckhuysen
Title: Heterogeneous catalysts for green synthesis of ethylene glycol ethers
Description: Ethylene glycol ethers are chemicals that are widely used in detergents and paints. They are also used for the synthesis of glycol diethers and can further convert into nonionic surfactants. However, the state-of-the art synthesis of ethylene glycol ethers is based on ethylene oxide as reactant. Besides being a highly toxic and explosive reagent, its production is highly dependent on fossil resources.
In this project, we aim to explore a greener and safer synthesis method without ethylene oxide while using heterogeneous catalysts that activate fatty alcohols and/or ethylene carbonate to produce ethylene glycol ethers. Double Metal Cyanides (DMC) are polymers wherein two or more metal ions are linked by cyanides. DMCs act as highly lewis acid catalyst and are able to catalyze ring-opening reactions, for example. Due to their high thermal stability, they have a low toxicity under reaction conditions. The aim of this project is to investigate how the structure of DMC catalysts including metal coordination and complexing agents, affects its catalytic performance. In this project, you will learn to synthesize DMC catalyst, use several spectroscopic techniques (UV-VIS, FTIR, NMR) and perform catalytic performance tests.
Supervisor(s): Xinwei Ye and Bert Weckhuysen
Title: Specify the location of species in Cu-zeolites for methane partial oxidation
Description: To reduce the dependence on oil resources, the catalytic activation of methane to high-value chemicals over metal-modified zeolites has attracted extensive attention. Methane can be relatively easily produced from renewable biomass resources. Cu-exchanged zeolites exhibit distinct reactivity in low temperature conversion of methane to methanol, which is one of the holy grails in catalysis, but the role of the catalyst in this reaction is still poorly understood. The speciation of copper (oxidation state, cluster size, location) is highly dependent on the Si/Al ratio, Al distribution within the zeolite, and Cu loading. The co-existence of multiple Cu species makes it difficult, for example, to distinguish the actual active site for methane partial oxidation. To gain better fundamental insights into the reaction mechanisms, we aim to develop methods for controlling the Cu speciation within mordenite zeolites. Ex-situ/in-situ spectroscopies will be extensively used to study structure-performance relationships for Cu-zeolites. Prepared catalysts will be further employed in methane partial oxidation reactions combined with operando spectroscopy techniques (UV-VIS, FTIR, NMR).
Supervisor(s): Adrian Hergesell, Ina Vollmer
Title: Low-temperature solvent-free chemical recycling of polyolefins through a multidisciplinary approach
Description: Only 12% of plastics (by weight) are recycled globally. This is mainly because the predominantly applied recycling technique of melting and re-extrusion produces a lower quality plastic, prohibiting circular use of plastics. Therefore, chemical depolymerization of plastic has been studied to produce monomers, which can be used to make high-quality plastic again. For polyolefins, however, high temperatures are needed to achieve this thermally and only a very mixed, low value hydrocarbon stream has been obtained thus far, requiring further energy-intensive upgrading. Hence, to enable the circular use of polyolefins new technologies are required that have a low energy requirement, low CO2 footprint and produce a high value hydrocarbon stream. Ball mills have been shown to facilitate challenging chemical reactions, which normally require high temperatures, without additional heating. Recently reported solid-state molecular organometallic catalysts (SMOMs) can convert conventionally inert small alkanes to valuable olefins with high selectivity – even at room temperature. As polyolefins are very long alkanes, in this project these organometallic catalysts will be leveraged in a novel strategy for the chemical recycling of polyolefins. Close contact between the solid molecular organometallic catalysts and the solid polymers in a ball mill can be utilized to convert polyolefins (or fragments thereof) into valuable smaller olefins with high selectivity. In this project, a strong collaboration with the Organic Chemistry and Catalysis group (Danny Broere) is foreseen.