Doctorate with distinction: Charles Ogolla strengthens research into sustainable materials at the University of Siegen

The examination committee consisted of Prof. Dr. Haring Bolívar, Prof. Dr.-Ing. Manuela S. Killian and Prof. Dr. Benjamin Butz (University of Siegen) as well as the external reviewer Prof. Dr. Marc Willinger (Technical University of Munich).

The work focuses on the question of how atomic and nanoscale processes influence the macroscopic properties of materials. The aim is to better understand these relationships and make them usable for the development of sustainable and resource-efficient technologies. The results provide important impulses, particularly for energy technologies.

The dissertation is divided into three central research areas: Gas sensor technology, electrocatalysis and electrochemical energy storage. Among other things, Ogolla investigated laser-structured carbon materials for the selective detection of CO₂. In the field of electrocatalysis, he analyzed cobalt boride-based catalysts for hydrogen and oxygen evolution and showed how nanoscale changes influence their activity and stability. He also dealt with structural and chemical processes in modern battery systems.

Researching these complex and sometimes highly reactive material systems posed particular experimental challenges. The working group was able to successfully overcome these challenges thanks to specially developed workflows, for example for cryogenic sample preparation. State-of-the-art transmission electron microscopy methods enabled so-called "scale-bridging" analyses, which link atomic structures and chemical properties with the macroscopic function of the materials.

The work was carried out in close collaboration with national and international partners, including the Max Planck Institute in Potsdam, the Helmholtz Institute in Ulm and the Lawrence Berkeley National Laboratory (USA).

Charles Ogolla's research makes an important contribution to the understanding of functional materials and opens up new perspectives for their use in sustainable technologies.