Friederike Jentoft

Jentoft Research Group

Our research interest is in catalysis. Catalysts facilitate chemical reactions and enable the efficient industrial production of chemicals and fuels. Our goal is to understand how catalytic reactions proceed and how performance of a catalyst is linked to its composition and structure. With this knowledge, we seek to design novel, more effective catalysts. Key competences of our laboratory are in the areas of catalyst preparation, structural and surface characterization, kinetics analysis, and spectroscopic monitoring of the adsorption and reaction of molecules on surfaces.

Target Reactions

Our target reactions are key steps in the conversion of fossil feedstocks or biomass to fuels or chemicals. Currently, we are interested in the following reactions and types of catalysis:

• Aldol reactions, methanol-to-olefins conversion (condensations/acid-base catalysis)
• Aromatics to paraffins, n- to iso-paraffins (hydrogenation and C-C bond cleavage or rearrangement/bifunctional catalysis with acid and metal function)
• Polyols to olefins (deoxydehydration, that is deoxygenation combined with dehydration/redox and acid-base catalysis)

Catalysts

The knowledge regarding catalysts for the above-listed reactions varies – for some reactions, no active and stable materials have been found, whereas for others, active materials exist and may even have been commercialized. Accordingly, some of our efforts target the preparation of novel materials while others are directed towards detailed understanding of the catalyst and the catalytic process. We seek to:

• Develop new supported transition metal oxo catalysts for polyol-to-olefin conversion, and stable solid acids for aldol condensation

• Explore entire classes of materials such as mixed transition metal carbides for reactions requiring bifunctional catalyst properties, thereby focusing on well-defined materials such as solid solutions for establishing structure-activity relationships
• Use uniform and well-defined materials such as zeolites, or well-characterized other solid acids for spectroscopic investigations of reaction mechanisms and deactivation processes.

Analytical Methods

One of our primary techniques for the investigation of catalysts is infrared (IR) spectroscopy, which delivers information on catalyst and adsorbate structures through their vibrational signatures. We are able to perform spectroscopic experiments over a wide range of temperatures and pressures, by using various reaction chambers and by applying transmission and reflectance mode. To complement the information from vibrational spectroscopy, we use diffuse reflectance ultraviolet–visible (UV–vis) spectroscopy, which provides insight into valence and coordination of catalyst components and the nature of surface species formed during reaction.

To analyze the composition of gaseous and liquid reaction mixtures, we use chromatography, mass spectrometry, and IR spectroscopy. Thermogravimetry (optionally combined with differential scanning calorimetry) is applied to monitor important steps in catalyst preparation, as well as the adsorption and desorption of probe molecules or reactants.