Advancements in EIS Analysis for (Photo)-Electrocatalytic Systems

The development of sustainable and green energy technologies has become critical in light of the ever-increasing environmental concerns and energy demand. Photo-electrocatalysis and electrocatalysis are poised to play a major role in such energy technologies. In addition to developing superior catalysts, research in (photo-)electrocatalysis focuses on understanding the dynamic aspects of the catalyst-electrolyte interface, which is crucial in deciding future directions. Electrochemical impedance spectroscopy (EIS), a frequency-based electroanalytical technique, has the ability to reveal such information about the electrochemical interface. Among the many advantages of EIS, one of the most notable is its ability to deconvolute various simultaneously occurring (photo-/electro-) chemical processes. Thus, EIS is now being used extensively in (photo-)electrocatalysis research, but its full potential has yet to be realized due to the complexities of data interpretation. It is widely recognized that EIS can provide information on charge transfer dynamics, kinetics of catalysis, and capacitance generation due to the substrate adsorption. The impedance output of an (electro- and photoelectro-)catalytic system is typically analyzed using an equivalent (electrical) circuit model or transmission line. However, these types of analyses necessitate prior understanding of the (photo-)electrochemical system (being studied) and selection of an appropriate circuit is also constantly debated. The ‘true’ significance of different circuit elements has also remained obscure to date. A few new approaches for analyzing EIS data have also evolved, including the distribution (function) of relaxation times (DRT), which is showing promise. Although this technique does not require prior knowledge of the catalytic system, it is significantly prone to misinterpretation of results. Thus, a huge amount of research is being conducted to bridge these knowledge gaps and establish the potential of EIS analysis in understanding photo-electrocatalytic and electrocatalytic reactions (and the electrochemical interface).

This Research Topic aims to compile some of these interesting advancements, whether for analysis of experimental data or theoretical work on EIS for electrocatalysis and photo-electrocatalysis. The main objectives include addressing specific questions such as: How can EIS be better utilized to understand the charge transfer dynamics in (photo-)electrocatalytic systems? What are the most effective methodologies for interpreting EIS data? How can new theoretical models improve the accuracy of EIS analysis? By answering these questions, the research aims to enhance the understanding of the electrochemical interface and improve the efficiency of (photo-)electrocatalytic processes.

To gather further insights in the application of EIS analysis to (photo-)electrocatalysis, we welcome articles addressing, but not limited to, the following themes:

- EIS data analysis for electrocatalytic and photo-electrocatalytic systems
- Fundamental works on EIS data analysis methodologies
- Theoretical investigations on the impedance output of a (photo-)electrocatalytic system
- Circuit models appropriate for various (photo-)electrocatalytic reactions
- Application of the DRT approach in (photo-)electrocatalysis

Keywords: Electrocatalysis, Photo-electrocatalysis, Electrochemical impedance spectroscopy, Equivalent circuit model, Distribution of relaxation times

Important Note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.