Microelectrochemical and microspectroelectrochemical studies of the incorporation of iron ions in nickel oxide and its effect on the oxygen evolution activity in alkaline water electrolysis - MicroSpec

• Applicant: Dr. Matthias Steimecke
• Subject Area: Physical Chemistry of Solids and Surfaces, Material Characterisation
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 529886413

The efficient storage of renewably generated electricity from wind and sun is one of the central challenges of this time. In addition to accumulators for feeding in and out electricity from generators and for consumers, electrolysis processes can provide important raw materials for the chemical industry. Hydrogen is the central molecule targeted by current developments. In addition to acidic membrane electrolysis (PEM), which relies on stable and efficient but at the same time rare and expensive materials, alkaline water electrolysis plays an important role in the necessary transformation of the feedstock supply from fossil to renewable energies. In recent years, decisive progress has been made in alkaline membranes, with alkaline membrane electrolysis (AEM) providing a major boost. Electrode materials consisting of inexpensive and readily available transition metal compounds can now be used. For these, however, there is a lack of understanding and a need for optimization, which necessitates further research, especially for the side of the kinetically strongly inhibited oxygen evolution reaction (OER). In this context, the nickel-iron double hydroxide (NiFe-LDH) is of particular importance, since it exhibits the lowest voltage losses. In this project, new nickel oxide-based catalysts for the oxygen evolution reaction will be investigated. The central idea of the project is to combine material knowledge of high temperature nickel oxides and method development of spatially resolved electrochemistry and in situ spectroscopy. On the one hand, powdered nickel oxides treated at different temperatures with different iron contents are to be comprehensively investigated in order to develop novel materials with high activity and simultaneous stability for electrochemical oxygen evolution. The approach to use nickel oxide-based instead of the hydroxide-based materials is derived from our own results in which high temperature nickel oxide showed comparable activity with significantly improved stability compared to the hydroxide. On the other hand, the combined in situ Raman microscopy and scanning electrochemical microscopy (SECM) will be further developed with novel approaches in this project. Finally, this combined setup will be used for the microelectrochemical and spectroscopic investigation of nickel (iron) oxide electrodes, providing new insights into activity-structure relationships and causes of deactivation and stability. Combined with the material findings, a deeper understanding of the dynamics of nickel-based electrocatalysts in terms of structural changes will be obtained, providing new approaches for more stable OER catalysts in alkaline electrolysis.

• DFG Programme: Research Grants