In the Etzold lab

chemical reaction engineering methodologies are employed in materials research, to inspire the synthesis of advanced functional materials for energy related applications and especially catalysis. Within this methodology the full potential for materials and processes within thermal-, electro- and photocatalysis is leveraged. For more details click on the topics below.

Porous carbons and carbides are synthesized, ranging in dimension from nano-sized towards hierarchically structured monoliths and from microporous molecular sieves towards mesoporous supports. During synthesis the crystallinity is adjusted, influencing chemical stability, heat and electrical conductivity. For porous carbons combining material properties can be achieved with core-shell carbons introduced by the Etzold lab. In post-treatments the surface is tuned from hydrophobic to hydrophilic character and for its acidity. Nanomaterials can be adjusted for its size on an atomic level by an layer-by-layer oxidation methodology established by the Etzold lab.

For catalytic applications noble and base metals are deposited in controlled amount, size and shape on these supports by various methods. Determination of intrinsic kinetic data, combined with advanced simulations is a cornerstone and allows the visualization of processes taking place inside reactors and to develop a deeper understanding. This enables for materials production to vary and adapt synthesis conditions, reactor configuration and post processing methods with the aim to influence materials properties.

Hollow shell of graphitic and mesoporous carbon obtained from oxidation of a core-shell carbon

The application of the tuned catalysts allows the determination of structure-activity relationships, which are employed for the process specific optimization of the materials properties. Besides tuning the active site on a nanolevel, optimization is carried out on all hierarchy levels to the macrostructure. Therefore, despite powders also catalysts foams and 3D printing approaches are employed.
Energy related applications studied concern on the one hand the production of renewable hydrogen by the aqueous phase reforming of biomass. On the other hand, investigations on the storage of hydrogen through the power to gas concept or with liquid organic hydrogen carriers are carried out. Further studied thermal catalytic reactions are the hydrotreatment of wasterwaters containing organochlorinated polutents, different selective hydrogenations and McMurry couplings

Hierarchically structured catalyst prepared by 3D printing, coating with high surface area matrix and immobilization of active metal

Major focus in electrocatalysis is on low temperature fuel cell catalysts and on boosting the activity for the sluggish oxygen reduction reaction at the cathode. The innovative approach employed, uses tiny amounts of Ionic Liquid (IL) to modify the active site microenvironment. This can reduce the blocking of platinum sites with non-reactive oxygenated species stemming from the product water. In parallel the concentration of the reactant oxygen is increase and in total lead to unprecedented activities of ORR catalysts.

Schematic representation of the catalytic microenvironment of an IL modified low temperature fuel cell catalyst

Photonic Crystal Fibres (PCF) are optical waveguides that transport light in an approx. 1 – 100 µm hollow core, which leads to outstanding interactions of light and matter. In the Etzold lab pristine and catalyst decorated PCFs are employed as continuous flow microreactor for in situ spectroscopy and photocatalysis. The enhanced interaction length, when comparing rolled up fibres with classical cuvettes, give access to sensing of ultralow concentrations. In photocatalysis the high power density per area achievable through focusing the light to the fibre core, speeds up the reaction rate. This allows monitoring reactions with very low quantum yield in reasonable time.

Using Photonic Crystal Fibres microreactor for photoactivated reactions or in situ spectroscopy
  • Horizontal tubular furnaces for gas/solid reactions under corrosive atmosphere (Cl~2~) up to 1600°C.
  • Fluidized bed furnace for gas/solid reactions under corrosive atmosphere (Cl~2~) up to 1300°C.
  • Vacuum furnace up to 2000°C
  • Hot press up to 450°C
  • Autoclave for catalytic high pressure experiments
  • Continuous flow gas phase catalyst rig with online GC
  • Rotating (ring) disc electrodes for electrochemical measurements
  • Electrochemical workstations (potentiostat, galvanostat, electrochemical impedance spectrometer)
  • Thermogravimetric balance coupled to mass spectrometer
  • Simulation software Presto Kinetics and Comsol Multiphysics