News

Tatiana Priamushko was doing her PhD in Prof. Freddy Kleitz's group at the Institute of Inorganic Chemistry - Functional Materials at the University of Vienna, Austria. The main focus of her research was the development of the ordered mesoporous mixed transition metal oxides for catalyzing oxygen evolution and reduction reactions. 

During her PostDoc research at HI ERN, she will combine her knowledge in materials science with the group's strong expertise in electrochemistry and perform an in-depth investigation of the electrocatalysts.

Welcome, Tatiana!

As you can see, we are working hard to build a bridge between degradation studies in aqueous model systems and real-world systems as degradation is pronounced very differently in the two worlds. In this work, we give a short overview on the differences between the two systems and how they affect electrocatalyst degradation. Thereby, we highlight several recent examples of how these effects were studied in the literature.

More details can be found here. 

Dr. Florian Speck of Team Electrochemical Energy Conversion received with honor the Jülich Excellence Award 2021 for his extraordinary dissertation on fundamental stability studies on catalysts in fuel cells and electrolyzers. 

More details of Dr. Florian Speck's works can be found on his personal page.

More details of the prize can be found on the news page on the HIERN webpage.

In this study, a photoelectrochemical scanning flow cell connected to an inductively coupled plasma mass spectrometer and equipped with a solar simulator, Air Mass 1.5 G filter, and monochromator was developed. The established system can assess basic photoelectrochemical metrics in a reliable and high-throughput manner as well as the in-situ photocorrosion under realistic light conditions.

More details on our setup development and results can be found here: https://doi.org/10.1021/acsmeasuresciau.1c00016

Ina Reichmann is a master student in chemical engineering at the Friedrich-Alexander-University and joins the team to write her master thesis within the OER sub-team.

Her master thesis will aim at broadening our understanding of the degradation of iridium as a catalyst for the oxygen evolution reaction. Specifically, the analysis of the volatile intermediates of OER on Ir/Ru catalysts (thin films and/or nanoparticles) via a Differential Electrochemical Mass Spectrometer (DEMS).

Marvin Gornik from Friedrich-Alexander University Erlangen-Nürnberg is joining our group for his master thesis. He will focus on stability and activity tests of noble metal catalysts for electrooxidation of isopropanol using different polyoxometallates as catalyst mediators. Polyoxometallates have proven to enhance the activity of noble metal catalysts during electrooxidations of alcohols such as methanol or ethanol. However, very less is known about their functioning in isopropanol electrooxidation and their stability. To gain more insights, he will investigate the dissolution of noble metal catalysts modified with polyoxometallates using a scanning flow cell (SFC) coupled with an online inductively coupled plasma mass spectrometer (ICP-MS).

Elisabeth Frömsdorf from Friedrich-Alexander University Erlangen-Nürnberg is joining our group for her master thesis. She will focus on the discrepancies between aqueous model systems (AMS) and membrane electrode assemblies (MEA) in proton exchange membrane water electrolyzer (PEMWE) with iridium based catalysts for oxygen evolution reaction (OER). To do so, she will investigate the pH dependence of stability and activity of iridium oxide catalysts using a scanning flow cell (SFC) coupled with an on-line inductively coupled plasma mass spectrometer (ICP-MS).

Gün Deniz Akkoç, a chemist from İzmir Institute of Technology (Turkey), has joined our group as a guest researcher. His research focuses on high-throughput screening of multi-metal-oxides for (photo)electrochemical performance and stability. Ultimately, the implementation of machine learning techniques is aimed to both efficiently explore and fine-tune the compositional space while creating a material library along the way.

Our new paper On the limitation in assessing the stability of oxygen evolution catalysts using aqueous model electrochemical cells was published today in Nature Communications. In this work, we tackle the discrepancy in the lifetimes of oxygen evolution reaction (OER) electrocatalysts between aqueous model systems (AMS), which are commonly employed in fundamental research and polymer electrolyte membrane based membrane electrode assemblies (MEA), which are state of the art in today's water electrolyzers.

With a newly developed setup, we present the first measurement of real dissolution rate in an MEA system. A striking difference in the stability of an iridium oxide catalyst in the MEA system was observed compared to our established scanning flow cell coupled to an inductively coupled plasma mass spectrometer (SFC-ICP-MS). Thus, a series of measurements in AMS was performed to search for the origins of this discrepancy.

Our results indicate two main contributors being responsible for the dissolution discrepancy—first, a general overestimation of the acidity of the conditions in the MEA. Second, iridium oxide stabilizes in the MEA system on longer timescales.

We expect our findings to lead to a better understanding of OER catalyst degradation and, subsequently, to better performing water electrolyzers.

More details can be found in Nature Communications under the following link: https://doi.org/10.1038/s41467-021-22296-9.

Nico Röttcher, master student at the Georg-August University Göttingen, will investigate electrocatalysts for the hydrogen oxidation reaction (HOR) for alkaline exchange membrane fuel cells (AEMFC). Thereby, he will focus on the performance of state-of-the-art electrocatalysts in high-current region using a gas diffusion electrode (GDE) setup. Additional electrochemical methods will be applied to gain mechanistic insights under realistic fuel cell potentials.