Fundamentals of Dynamic Electrochemistry

This research area focuses on the fundamentals of dynamic (AC) or pulsed electrolysis, a promising but relatively unexplored technique in electrosynthesis and electrolysis. A theoretical framework to explain selectivity improvements under these conditions is notably absent. Moreover, dynamic conditions are essential for kinetics and process analysis, model discrimination, monitoring, and diagnosis. Our model-based approach, nonlinear frequency response analysis (NFRA) addresses these aspects (Figure 1), concentrating on two examples: the oxygen reduction reaction (ORR) under alkaline conditions and the carbon dioxide reduction reaction (CO2RR) in aqueous electrolyte . For ORR, the emphasis is on kinetic model discrimination, while the analysis for CO2RR extends towards improving product selectivity.

Figure 1: Nonlinear Frequency Response Analysis (NFRA) is a comprehensive theoretical framework used to study electrochemical processes under dynamic conditions, such as alternating potential or current. The linear, known as electrochemical admittance/impedance (G1(ω)), along with the nonlinear frequency response functions (G2(ω, ω) and G2(ω, -ω)), have applications in process analysis, monitoring, and intensification.

Oxygen Reduction Reaction Kinetic Model Discrimination

The kinetics of ORR is perhaps one of the most studied topics in electrochemistry. However, there is still no full understanding of this reaction. In terms of a mechanistic analysis of the ORR, the major difficulty lies in the fact that the ORR is a complex process involving the transfer of up to 4 electrons. Consequently, different kinetic schemes can be formulated for this reaction. more

Carbon Dioxide Reduction Product Selectivity Under Dynamic Conditions

Electrochemical CO2RR on silver primarily produces carbon monoxide and hydrogen. There is significant discussion in the literature about enhancing CO yield under pulsed electrolysis conditions. However, the current understanding does not provide a theoretical explanation for this effect. In this project, we propose using the NFRA as a theoretical framework to investigate the improvement in selectivity under pulsed electrolysis conditions. more