Dr. Norbert Steinfeldt

Topics of the micro process engineering group are the synthesis of active nanostructured catalysts and their testing as well as the development of continuous flow processes for multiphase reactions (gas/liquid, gas/liquid/solid, liquid/solid). The application of microstructures not only minimizes the use of natural resources, but also allows the investigation of the influence of reaction parameters on important target parameters such as conversion, yield, and selectivity, usually at avoiding mass transfer limitations and temperature gradients. Another advantage of the continuous operation mode is the rapid detection of catalyst activations or deactivations, which can thus be investigated in a targeted manner. In addition to microstructured glass components, various falling film microreactors and a modular, computer-controlled Ehrfeld system are available for such investigations.

In the liquid phase synthesis of catalytically active and selective noble metal nanostructures, one focus of material synthesis is on studies of the influence of synthesis parameters on nucleation and particle growth since both processes determine the size distribution and composition of the nanostructures. Such information can be obtained by combining small angle X-ray scattering (SAXS) with X-ray diffraction (XRD) and electron microscopy (TEM). Methods are also being developed to deposit the synthesized nanostructures onto oxide support materials without changing the size distribution. Applications of such materials include selective hydrogenation and dehydrogenation and the conversion of renewable raw materials into higher value products. The group is also involved in the synthesis of photocatalytically active materials such as titanium dioxide (TiO2), polymeric carbon nitrides (p-C3N4), and metal sulfides (e.g., InxZnySz), which have applications in photocatalytic wastewater treatment as well as in the photocatalytic synthesis of fine chemicals. The aim of these studies is to identify those synthesis parameters whose control allows it to optimize the photocatalytic properties of the prepared materials.