Controlling oxygen electrocatalysis on model oxide surfaces using electrolyte design

• Applicant: Dr. Marcel Risch
• Subject Area: Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry ; Physical Chemistry of Solids and Surfaces, Material Characterisation
• Term: from 2018 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 397636017

• Final Report Year: 2023

Final Report Abstract

The oxygen evolution reaction (OER) is one of the most fundamental processes for energy storage both in nature and technology. The high overpotential of the OER is one of the grand challenges faced in oxygen electrocatalysis and significant improvement is key for sustainable production of renewable energy carriers in a future hydrogen economy. Virtually all previous studies of activity and mechanism focused on the composition and structure of the catalytic electrode, while this project focuses on the influence of the microenvironment, specifically the electrolyte composition to identify structure-activity relationships. In proof-of-concept experiments, the onset of the OER depended on water concentration and the anion of room temperature ionic liquids (RTIL) in RTIL-water mixtures on polycrystalline Pt for potentials relative to a bipolar Ag/AgCl reference electrode, while it did not depend on the RTIL cation, specifically the chain length. The reversible hydrogen electrode is defined by the hydrogen redox in the used electrodes. When the potentials were expressed relative to an approximation of the hydrogen redox, then the dependence on the RTIL anion vanished, which suggests that the RTIL anion controlled the concentration of protons available for the OER. While the RTIL composition clearly affected the OER, an improvement over conventional aqueous electrolytes was not observed, from which it is concluded that the OER is in an optimal microenvironment in aqueous electrolytes.

Publications

• Peroxide Yield of the (001) La0.6Sr0.4MnO3 Surface as a Bifunctional Electrocatalyst for the Oxygen Reduction Reaction and Oxygen Evolution Reaction in Alkaline Media. Batteries & Supercaps, 2(4), 364-372.
  Köhler, Lennart; Szabadics, Lukas; Jooss, Christian & Risch, Marcel
  
• Aufbau und Charakterisierung eines differenziellen Massenspektroskopie Systems mit einer elektrochemischen Doppelelektrodenflusszelle zur Untersuchung der Wasseroxidation, Master Thesis, 2021, Georg-August-Universität Göttingen
  Stender, F.J.
  
• A Modular Double Electrode Flow Cell with Exchangeable Generator and Detector Electrodes. ChemElectroChem, 10(13).
  Stender, Frederik J.; Obata, Keisuke; Baumung, Max; Abdi, Fatwa F. & Risch, Marcel