Electrocatalysis of hydrogen and oxygen in alkaline electrolytes at extreme temperature conditions

• Applicant: Dr. Maren-Kathrin Heubach
• Subject Area: Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 563617622

In the future, green hydrogen will serve as an important renewable energy source and energy carrier medium, produced in water electrolyzers with electricity from renewable sources, such as solar, wind or hydropower. It can supply electrical and thermal energy on demand using fuel cells. The underlying electrochemical processes, the hydrogen and oxygen evolution reactions, and the hydrogen oxidation and oxygen reduction reactions take place on catalysts that are constantly being optimized in terms of efficiency, material costs and availability. The electrocatalytic reactions are mainly investigated at room temperature, whereas the working temperature of water electrolyzers and hydrogen fuel cells is usually 60-80°C. In addition, there are the so-called cold starts prevalent in northern counties in winter, with the electrolyte being below the freezing point and in countries near the equator near the boiling point. The project proposes research on this important knowledge gap and focuses in nickel-based materials and aqueous KOH solutions. The electrode reactions and the degradation of the catalysts will be investigated at temperatures from below the freezing point to near the boiling point of the electrolyte used. The investigations focus on the following questions: How do the mechanisms and kinetics of the electrode reactions change in the frozen electrolyte and the electrolyte near the boiling point compared to measurements at room temperature? What influence does the concentration of the electrolyte, as well as the pH value and conductivity, have in the different temperature ranges? How does the corrosion of the catalyst change at different temperatures? Various electrochemistry, materials and surface chemistry, and spectroscopy methods under temperature control are combined to answer these questions: Electrochemical measurements such as cyclic voltammetry, Tafel plots and electrochemical impedance spectroscopy provide deep insights into the electrochemical processes. Electron microscopy, X-ray photoelectron spectroscopy and scanning probe microscopy can analyze the changes in the structure and chemical composition of the catalyst surface before and after the electrochemical measurements. The temperature control will be extended to advanced methods, such as in Raman spectroscopy and scanning probe microscopy. This extended methodology will allow the complex reaction mechanisms to be broken down at the molecular level and the reactive sites to be identified with great accuracy. The high-risk, high-return project described here can contribute significantly to a deeper understanding of electrocatalytic processes and corrosion in electrolyzers and fuel cells at extreme temperature conditions.

• DFG Programme: WBP Fellowship
• International Connection: Canada
• Host: Professor Dr. Gregory Jerkiewicz