Research

The research in the Inorganic Chemistry and Catalysis (ICC) group involves the synthesis, characterization, and performance testing of well-defined heterogeneous catalysts and related functional materials for gas sensing, energy storage, photo-, electro- and thermochemical conversion processes, but also of materials encountered in the environment. Strongholds are materials synthesis, including the synthesis of zeolites, metal-organic frameworks, as well as well-defined metal and semiconductor nanoparticles. Furthermore, we develop and apply a wide variety of advanced spectro(micro)scopy techniques for the study of functional materials ‘at work’, that is, in space and time, such as solid catalysts under working conditions .

The fundamental scientific challenge is to establish the relationship between structure, composition, and function of nanomaterials at different length scales ranging from the single atomic and molecule level over the micro-, meso- and macroscopic scale up to the level of, for example, small reactor set-ups. We are convinced that fundamental problems in catalysis and sustainability require such a multi-scale science approach.

The ICC group works on various topics of analytical chemistry and heterogeneous catalysis, including but not limited to the valorization of fossil (i.e., crude oil and natural gas) as well as renewable resources (i.e., carbon dioxide, municipal waste, plastic waste, and biomass) for the production of transportation fuels, base and fine chemicals as well as materials, including plastics, paints and coatings. Different types of catalysis are explored: thermal catalysis, photocatalysis and electrocatalysis. Other topics include environmental analysis, chemometrics, data mining, and plasmonic sensing.

Research Themes

The research themes of the Inorganic Chemistry and Catalysis (ICC) group.

  • Catalyst synthesis, including assembly of microporous and mesoporous materials, and well-defined metal nanoparticles
  • Development of structure-performance relationships and expert systems in heterogeneous catalysis
  • Probing catalytic events with in-situ and operando techniques
  • Probing catalyst synthesis and crystallization processes with in-situ techniques
  • Development of advanced X-ray spectro(micro)scopic techniques for catalyst characterization
  • Thermocatalytic activation of methane and light alkanes
  • Electro-, photo- and thermocatalytic CO2 activation and conversion into value-added hydrocarbons
  • Fischer-Tropsch synthesis
  • Polymerization catalysis
  • Methanol-to-hydrocarbon catalysis
  • Catalytic cracking
  • Industrial (refinery) catalytic processes
  • Biomass catalysis, including lignin and chitin depolymerization, as well as fat industry valorization processes
  • Environmental catalysis, including CO oxidation and DeNOx chemistry
  • Environmental analysis, including studying nanoplastics
  • Analysis of objects of art and cultural heritage
  • Waste valorization, including chemical recycling of plastics
  • Photo and electrocatalysis, including direct and indirect CO2 and H2O activation by sunlight
  • Synthesis, modification, characterization and testing of zeolites and metal organic frameworks, including their thin-films
  • Catalytic coatings for outdoor and indoor air pollution control
  • Time-resolved spectroscopy studies of semiconductor (nanoparticles) for photocatalytic reactions

Research Triangle

Assembly

Spatiotemporal control of composition, structure, and location of active sites and phases in a single catalyst particle, including a catalyst pellet and extrudate.

Building blocks

  • Zeolites
  • Mesoporous materials
  • Amorphous oxides
  • Microporous (silico-) aluminophosphates
  • Metal organic frameworks
  • Metal as well as metal oxide, carbide and nitride nanoparticles
  • Semiconductor thin films

Assembly techniques

  • Homogeneous deposition precipitation
  • Impregnation
  • Ion exchange
  • Colloidal synthesis
  • Spark ablation
  • Hydrothermal crystallization
  • Electrodeposition

Performance

  • Fischer-Tropsch synthesis
  • Alcohol-to-Hydrocarbon conversion
  • Alkane cracking
  • Lignin and chitin conversion
  • Methane and light alkane activation
  • Selective hydrogenation and hydrodeoxygenation
  • De-NOx catalysis
  • CO2 and CO catalysis
  • Water electrolysis
  • Selective oxidation reactions
  • Photocatalysis
  • Electrocatalysis
  • Polymerization catalysis

Characterisation

  • in-situ infrared spectroscopy
  • in-situ UV-Vis-NIR diffuse reflectance spectroscopy
  • in-situ (confocal) fluorescence microscopy, including single molecule detection and monitoring
  • in-situ Raman spectroscopy, including surface-enhanced Raman spectroscopy (SERS) and shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS)
  • in-situ X-ray absorption and fluorescence spectroscopy and microscopy
  • in-situ X-ray diffraction, including grazing-incidence X-ray diffraction
  • Transmission and Scanning Electron Microscopy (TEM and SEM)
  • in-situ spectro(micro)scopy techniques, making use of Raman, ultraviolet-visible, luminescence, fluorescence, infrared, and X-ray spectroscopy
  • Atomic force microscopy (AFM) in combination with spectroscopy, including tip-enhanced Raman spectroscopy (TERS) and photo-induced force microscopy (PIFM)
  • Time-resolved photoluminescence and transient absorption spectroscopy

Programme Design

A. Assembly of solid catalysts and functional materials for a more circular economy

Based upon concepts of inorganic chemistry, synthesis of solid catalysts involves control of composition, structure, and location of active phases in three dimensions in a catalyst particle, including catalyst pellets and extrudates. The production of solid catalysts resembles the production of a three-dimensional device rather than synthesis of a chemical compound. The materials that are used as building blocks for assembling catalysts include zeolites, mesoporous materials, solid acids and bases, metal organic frameworks, as well as many other crystalline and amorphous materials. The applied assembly techniques are homogeneous deposition precipitation, impregnation, ion exchange, colloidal synthesis, spark ablation, electrodeposition, and hydrothermal crystallization.

B. Development and application of advanced characterization methods to fundamentally understand the function of solid catalysts and other nanomaterials

The spearheads in the group’s characterization toolbox are development and application of in-situ methods using vibrational spectroscopy (IR/Raman), optical spectroscopy (UV-Vis-NIR, fluorescence and luminescence), X-ray absorption spectroscopy (EXAFS and XANES), X-ray diffraction, and X-ray microscopy. For all in-situ techniques specially designed spectroscopic-reaction cells have been developed to ensure that the active catalyst material is studied under relevant reaction conditions. Several in-situ techniques are also combined in one set-up (UV-Vis/Raman, UV-Vis/Raman/XRD or UV-Vis/Raman/XAFS and SAXS/WAXS/XAFS), giving distinct advantages over a single spectroscopy approach. More recently, attention is directed toward adding spatial resolution to the above-described in-situ spectroscopic techniques. Examples include transmission X-ray microscopy and tomography making use of soft or hard X-rays, tip-enhanced Raman spectroscopy, atomic force microscopy combined with surface-enhanced Raman, confocal fluorescence and Raman microscopy, synchrotron-based IR microscopy, UV-Vis micro-spectroscopy, spatially offset Raman spectroscopy, and photo-induced force microscopy. The spectroscopic tools developed are as well applied to probe catalyst synthesis and crystallization processes, but also to study samples from the environment, for example micro- and nanoplastics, or objects of art.

C. Catalysis to make our manufacturing processes more sustainable

Several topics in the field of heterogeneous catalysis are studied:

  1. Activation of methane and light alkanes.
  2. Activation of CO2
  3. Production of base chemicals and fuels from biomass, including the valorization of lignin, and chitin.
  4. Automotive and environmental catalysis, including reactions with NO and CO.
  5. Fischer-Tropsch synthesis.
  6. Alcohol-to-hydrocarbon catalysis, including methanol and ethanol conversion.
  7. Photo- and electrocatalysis, including the solar fuels research.
  8. Bulk and fine chemicals production, including selective oxidation, hydrogenation and deoxygenation reactions.
  9. Refinery catalysis: present and future hydrocarbon conversion processes for fuels and chemicals

Societal and Technological Relevance

The impact of our education and research program can be judged by the quality of the people that have graduated from our group. Many of our PhD students and postdoctoral fellows have entered prestigious industrial laboratories (e.g., Shell, BASF, Total, Chevron, ExxonMobil, Albemarle, Sabic, Philips, Dow Chemical, Haldor Topsoe and Avantium) and many of them hold key positions that are still close to catalysis research and development. A long list of our former PhD students and postdocs are now affiliated with universities and important research institutes and climbing the academic ladder towards full professorship.

The direct relevance of catalysis studies at the Inorganic Chemistry and Catalysis group involves the efficient use of fossil resources, including natural gas and crude oil as well as the sustainable use of waste, including biomass, CO2 and plastics for the production of fuels, base and fine chemicals as well as materials, including plastics, paints and coatings. Essential topics are energy, materials scarcity, resource efficiency, sustainability, and circularity. This explains why we are working on a wide variety of topics, such as Fischer-Tropsch synthesis, catalytic biomass conversion, environmental catalysis, solar fuels production, plastic waste valorization, and environmental analysis. This involves the wide range of heterogeneous catalysis, including but not limited to thermal catalysis, photocatalysis and electrocatalysis.

The relevance of our programs is highlighted by many contacts with industry, research institutes, and governmental institutes all over the globe. Patent applications are filed with our research partners when appropriate.