Electrochemical Process Engineering 

In the electrochemical process engineering group we work on the interplay of electrode kinetics, mass transfer, fluid dynamics, and materials. We aim at understanding electrochemical processes qualitatively and quantitatively. This understanding is the basis for systematic, knowledge-based optimization. We are currently working on the oxygen reduction reaction, capacitive deionization, alkaline fuel cells, direct methanol fuel cells and microbial fuel cells.

Electrode kinetics

electrochemproeng_group_fig1Electrode kinetics are at the heart of most electrochemical processes. To describe electrochemical processes quantitatively, kinetics and rate constants need to be determined precisely. Next to well known Tafel- and Butler-Volmer kinetics we take into account intermediates covering the electrode surface. This allows to describe and model features of complex mechanisms. On the one hand we analyze half-cell reactions at idealized electrodes such as RDEs and RRDEs. Our main focus, however, is on technical, porous electrodes such as gas diffusion electrodes, which exhibit a highly complex behavior.

Online diagnosis and dynamic methods

electrochemproeng_group_fig2Online diagnosis and dynamic experimental methods yield valuable information. Parallel processes often cannot be differentiated by steady-state measurements such as polarization curves. Dynamic analysis can accomplish this by separating processes with different time constants. Thereby limiting processes are identified and parameters are determined more precisely. We employ taylor-made experimental setups and support experimental results by model based analysis. Among others we use the following techniques: electrochemical impedance spectroscopy (EIS) , Total Harmonic Distortion (THD), cyclic voltammetry (CV) differential electrochemical mass spectrometry (DEMS).

Knowledge-based process optimization

electrochemproeng_group_fig3Based on quantitative models we systematically assess the limiting steps of electrochemical processes. Experimentally validated reaction kinetics and dynamic analysis are the basis for physically well-founded models of technical electrodes. If possible, we use rigorous mathematical optimization strategies to systematically improve processes. Where rigorous mathematical optimization is not posssible, we conduct scenario based analyses to identify favorable operating parameters and process designs.

  last changed 04.09.2017
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