Max-Planck-Forschungsgruppe - Elektrochemie für Energieumwandlung

The Electrochemistry for Energy Conversion group primarily aims to utilize electrochemical methods coupled with surface science and other instrumental analysis techniques to investigate the links between surface and electrolyte properties and electrocatalytic activity. The focus is on reactions that are of interest for energy conversion, storage and utilization. Applications and inquiries from highly motivated master students are welcome. 

Generation of fuels from electricity

In this concept electricity from renewables at peak production would be used to produce hydrogen by water electrolysis. Such hydrogen could later be used in fuel cells to generate electrical energy, thus allowing energy storage from renewable energy sources.

The group is intensively involved in the testing of additively manufactured 3D-structured Ni-based electrodes (Figure 1), fabricated in cooperation with the research group of Dr. Stefan Kleszczynski from the University of Duisburg-Essen (UDE), using Laser Powder Bed Fusion of Metals (PBF-LB/M). We have applied these 3D-structured electrodes for the oxygen evolution reaction (OER), hydrogen evolution reaction (HER), glycerol oxidation reaction (GOR), nitrogen reduction reaction (NRR) and others. We carry out detailed investigations of their electrochemical properties and the dependence of their performance on their surface geometry. We have shown that the geometry of the surface structure has a profound effect on activity, selectivity and stability of the electrodes for OER, HER, alcohol oxidation, and nitrogen reduction. We demonstrated that the optimal surface structures, i.e., the ones displaying the highest activity, are different for different reactions and there is no single “optimal surface structure” that is generalizable

Using electricity to produce wide-use chemical products

Another route for the utilization of electric power is the direct synthesis of wide-use chemicals. For instance, ORR can go through two different pathways, the so-called 4-electron one, which is desirable in fuel cells, and the 2-electron one which is not desirable in that case, but results in the generation of hydrogen peroxide, which is a widely used chemical an oxidant and a disinfectant. Therefore, a good control of the selectivity of ORR is of high interest for different applications.

We have tested a series of carbon materials as electrocatalysts for the oxygen reduction reaction (ORR). In particular, we are interested in controlling the reaction selectivity and optimizing the catalysts for the production of H2O2

involved with the investigation of “model” carbon electrodes to gain a deeper understanding of the properties of carbon materials and their influence on ORR performance. We are investigating the influence of defects, surface oxygen functional groups, as well as the presence of alkali cations in the electrolyte on ORR selectivity of glassy carbon and base- and edge-terminated pyrolytic graphite in acidic and alkaline media. We show how an interplay of these factors influences the electrode/electrolyte interface, influencing adsorption, the potential of zero charge, and, consequentially, electrocatalytic properties. The study is currently expanded to alkaline and other electrolytes, as well as better defined graphitic structures.