All projects by Prof. Bert Weckhuysen (UU):
Chemical Imaging of Solid Catalysts with Nano-Infrared Spectroscopy
Exploring the Complexity of Pore Space of a Catalyst Particle
A Multiscale Catalysis and Engineering Approach to CO2-to-X
Nanosensors for local halide concentrations
Catalysis by Metal-based Zeolites for Bulk Chemicals Synthesis from Carbon Dioxide and Renewably Resourced Hydrogen
1st supervisor and 1st promotor: Prof. Bert Weckhuysen
Affiliation: Utrecht University
Research theme: Storing electricity from renewable sources in chemical bonds
CO2hydrogenation is key for the storage of excess renewable electricity available in the form of electrolytically derived H2. Storing electrical energy in chemical bonds, thereby converting CO2into useful chemical building blocks, has clear advantages given the existence of current chemicals production processes. Large-scale CO2reduction with renewable H2remains a challenge because the current generation of solid catalysts are not active, selective and stable enough.
In this project, we will build further on our recent activities for catalytic CO2reduction into CH4by nickel, but the attention will be on designing new bifunctional catalysts, which are able to perform C-C coupling from initially activated CO2. This will be done by combining supported metal catalysts, able to activate CO2into either CO, CH4or CH3OH, followed by their subsequent conversion into higher hydrocarbons by adding functionalized zeolites.
The research will focus on finding the right combination of CO2-activating metal nanoparticles (in terms of location, particle size, alloying, and promotors) and zeolite-based supports (in which acid strength and distribution will be controlled). Inspiration for the latter system will be derived from known methane dehydroaromatization, methanol-to-hydrocarbons and Fischer-Tropsch synthesis catalysts. Mechanistic understanding will be gathered by operando spectroscopy and microscopy.
Key words:
- Renewable energy storage
- CO2 hydrogenation
- Zeolite-based chemistry
- Spectroscopy
- Mechanistic understanding
Chemical Imaging of Solid Catalysts with Nano-Infrared Spectroscopy
1st supervisor and 1st promotor: Prof. Bert Weckhuysen
Affiliation: Utrecht University
Research theme: Catalyst Diagnostics to Develop More Active Catalysts
Understanding the active site and its dynamics in a solid catalyst is vital to develop better ones. Such understanding can only be obtained when we have sensitive tools to chemically image solid catalysts, preferentially at the nanoscale. Scanning probe methods, such as Scanning Near-Field Optical Microscopy (SNOM), can overcome the diffraction limit of light, and in particular the scattering-type version s-SNOM combines a high-spatial-resolution of ~ 10 nm with ultra-sensitivity, in principle down to the single molecule level, by spatially confining the light-matter interaction. Photoinduced force microscopy (PiFM) is a promising SNOM technique, which probes the dipole-dipole moment interaction between the AFM tip and catalyst.
In this work, we will build further on our work to use a recently acquired PIFM instrument to chemically image zeolite, metal organic framework and zeolitic imidazolate framework thin-films. We propose to investigate zeolite-based model catalysts, differing in their composition (Al content) and framework structure (i.e., MFI, FAU and BEA); and study with IR sensitive probe molecules (e.g. pyridine) their local acidity, as well as the local concentration of Al framework atoms. In a second stage of the study, we will investigate catalytic reactions to explore the reactivity of the zeolite-based model catalysts.
Keywords:
- Chemical Imaging
- Active Site
- IR Nano-spectroscopy
- Atom Force Microscopy
- Mechanistic understanding
Studying the Genesis of Nanobubbles on Zeolite and Metal Organic Framework Thin-Films by Scanning Probe Microscopy
Joint Doctorate
1st supervisor and 1st promotor: Prof. Bert Weckhuysen (UU)
2nd supervisor and 2nd promotor: Prof. Detlef Lohse (UT)
3rd promotor: Prof. Xuehua Zhang (UT)
Affiliation: Utrecht University and University of Twente
Research theme: Catalyst Diagnostics to Develop More Active Catalysts
Thin-films of porous oxides are interesting to investigate fundamental aspects of diffusion, adsorption and catalysis. In the past years, it has been possible to characterize the formation processes of zeolite and metal organic framework (MOF) thin-films with scanning probe microscopy methods, including liquid-phase Atomic Force Microscopy (AFM) as well as nano-IR-AFM. We wish to build on this expertise and investigate the genesis of nanobubbles at the surface of thin-films of zeolites and MOFs by using liquid-phase AFM as well as Kelvin probe microscopy. The latter method is sensitive to surface potentials, hence provides information on the type of elements, and their coordination.
In a first stage of the project we make use of solvent exchange (ethanol by water) and temperature variations (cold liquid on hot thin-film surface) to induce the local formation of gas bubbles. This will be done for zeolite thin-films in which the Si/Al ratio has been altered. In a second stage of the project, we will make use of MOF thin-films active in (photo-) electrocatalysis and induce the formation of gas bubbles during water splitting. The goal is to correlate surface heterogeneities, as probed with Kelvin probe microscopy, with bubble formation during e.g. solvent exchange and catalysis.
Keywords:
- Chemical Imaging
- Scanning Probe Microscopy
- Zeolites and Metal Organic Frameworks
- Nanobubbles
- Electrocatalysis
Quantitative Determination of Particle-Size Dependent Active Sites in Supported Metal Nanoparticles with SHINERS
Joint Doctorate
1st supervisor and 1st promotor: Prof. Bert Weckhuysen (UU)
2nd supervisor and 2nd promotor: Prof. Albert van den Berg (UT)
Co-promotor: Florian Meirer (UU)
Affiliation: Utrecht University and University of Twente
Research theme: Catalyst Diagnostics to Develop More Active Catalysts
Raman spectroscopy is a powerful method for solid catalyst characterization under operando conditions. However, its sensitivity often hampers the detection of surface adsorbates and reaction intermediates. Shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) has turned out to be a valuable addition to the catalyst characterization toolbox. SHINERS requires Au or Ag nanoparticles covered by a thin dielectric oxide coating, such as SiO2 or Al2O3, to minimize plasmonic side-reactions.
In this project, we will use spark ablation technology to deposit metal nanoparticles of various sizes and chemical compositions on shell-isolated Au and Ag nanoparticles (SHINs). These metal/SHINs will allow to investigate the adsorption of probe molecules, such as NO and CO, as well as performing structure-sensitive (e.g. CO2 and acetylene hydrogenation) and structure-insensitive (e.g. ethene hydrogenation) reactions under operando conditions.
In a second stage of the project, we will use periodically structured wafers of plasmonically active materials (i.e. Au and Ag) with well-defined Raman enhancement factors, and subsequently coat them with a non-porous SiO2 or Al2O3 layer. Metal nanoparticles with variable size and composition can then be deposited on these coated wafers, thereby offering unique opportunities for performing size-dependence catalysis in a quantitative manner and under operando conditions.
Keywords:
- Raman spectroscopy
- Operando surface characterization
- Structure-sensitivity
- Hydrogenation catalysis
- Particle size effects
Exploring the Complexity of Pore Space of a Catalyst Particle
Joint Doctorate
1st promotor: Prof. Bert Weckhuysen (UU)
2nd promotor: Prof. Albert van den Berg (UT)
1st supervisor and co-promotor: Assistant Prof. Florian Meirer (UU)
2nd supervisor and co-promotor: Associate Prof. Mathieu Odijk (UT)
Affiliation: Utrecht University and University of Twente
Research theme: Smart Biomass Conversion
Functional materials are essential for modern society and of those catalysts play an important role in producing everyday life materials, such as plastics and fuel. To make these materials more efficiently and sustainably we need to understand a catalysts nature in order to design a better one. Porosity is such an important catalyst property, which is needed to effectively bring the (feedstock) molecules that should be transformed/consumed to the (catalytic) site that generates the product.
In rationally designing a catalyst’s pore space it becomes possible to tune its properties towards the desired function. However, the pore space of a catalyst is highly complex and involves length scales from the atomic level to fractions of a millimeter. Therefore, many aspects of how feedstock molecules travel through these pores are still poorly understood.
The aim of this research project is to unravel some of these mysteries by designing model systems using state-of-the-art 3D printing technology to mimic porous materials with increasing levels of complexity. Inspecting the diffusion properties of these models will then allow following diffusion probes, while they travel through the pores. By connecting these observations to simulations we will be able to predict mass transport properties of future rationally designed improved catalysts.
Keywords:
- Mass transport
- Hierarchically complex porous materials
- Micro- and nanofluidics
- Single particle tracking
- X-ray microscopy
A Multiscale Catalysis and Engineering Approach to CO2-to-X
1st supervisor and 1st promotor: Prof. Pieter Bruijnincx (UU)
2nd supervisor: Prof. Niels Deen (TU/e)
Affiliation: Utrecht University
Research theme: Storing Electricity from Renewable Sources in Chemical Bonds
Sustainable energy, materials and chemicals require a transformation to industrial processes with zero or, better, negative CO2 emissions. To close the carbon cycle, new technologies need to be developed that utilize CO2 as raw material. Capture at point sources could, for example, reduce emissions by 60% and provide access to huge amounts of CO2 feedstock for further conversion. CO2 reduction should then make use of renewably sources electrons or hydrogen to achieve the desired impact.
From a chemical and process point of view, reducing CO2 to a slate of valuable products, be it chemical intermediates or final products such as renewable energy carriers still require many scientific and technological hurdles to be taken. Here we aim to develop new molecularly-defined catalyst materials and new engineering solutions allow continuous CO2-to-X processes.
Keywords:
- CO2 reduction
- Amine-mediated scrubbing
- Reactor design
- Homogeneous and Heterogeneous Catalysis
- Biphasic Catalysis
Nanosensors for local halide concentrations
1st promotor: Prof. Bert Weckhuysen
2nd promotor: Prof. Alfons van Blaaderen
1st supervisor: Assistant Prof. Freddy Rabouw
Affiliation: Utrecht University
Research theme: Catalyst Diagnostics to Develop More Active Catalysts
Catalysts make the production of chemicals—for example, plastics or fuel—faster and less energy expensive. They usually consist of a highly porous material with a large surface area. The surface contains active reaction sites where the desired chemical reaction can take place. Essential to the operation of a catalyst is the transport of reactants to deep inside the porous structure as well as transport of the products to the outside. The pore structure of many catalysts is very complex with interconnected channels of varying width. As a result, the transport behavior of chemicals through such pores is not yet fully understood.
The goal of this project is to develop nanosensors that change fluorescence color when exposed to halide ions. By embedding these in a pore structure of interest and introducing halide ions, diffusion of the ions into the structure can be followed in real time and with high spatial resolution using optical microscopy. This method will be used to measure the diffusion of ions in samples of increasing complexity, and to compare the results to simulations. This will improve our understanding of diffusion and transport of chemicals on the micro- and nanoscale.
The project will involve chemical synthesis of samples in collaboration with a technician, sensitive optical microscopy and spectroscopy, and custom data analysis and fitting to mathematical models. Experience in programming languages such as Python or similar is recommended.
Key words:
- Nanosensor
- Diffusion
- Optical microscopy
- Fluorescence
- Pore structure
Weckhuysen is an elected member of the Royal Dutch Academy of Sciences (KNAW), Royal Flemish Academy of Belgium for Sciences and Arts (KVAB), the Netherlands Academy of Technology and Innovation (NATI), the Royal Holland Society of Sciences (KHMW), and the European Academy of Science; an alumnus elected member of the Young Academy (DJA, 2005-2010) of the KNAW; and a fellow of the Royal Society of Chemistry (FRSC), the American Association for Advancement of Science (AAAS) and ChemPubSoc Europe. Weckhuysen serves on many boards and panels for national and international research.
The research group of Bert Weckhuysen has been active for many years in the design, synthesis, characterization and application of catalytic solids for the conversion of fossil (crude oil & natural gas) and renewable (biomass, waste and CO2) feedstock into transportation fuels, chemicals and materials. He is internationally renowned for the development of in-situ spectroscopy and microscopy for studying catalytic solids under realistic conditions. This approach has provided unique insights in the working and deactivation mechanisms of catalytic processes, as well as in the internal architecture of functional materials.
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