In his cumulative dissertation titeld Laser spectroscopic in-situ diagnostic of Fe-microparticles in thermochemical energy storage processes, Maximilian Dorscht investigated how the elemental composition of the surfaces of iron microparticles can be analyzed in a time-resolved, non-intrusive, and in-situ manner during their thermochemical oxidation. The work was carried out in the context of the Clean Circles project, in which iron is investigated as a carbon-free energy carrier for the storage and transport of renewable energy.

For this purpose, Laser-Induced Breakdown Spectroscopy (LIBS) was methodologically advanced to quantitatively determine the elemental composition of the particle surface. First, parameter studies were conducted on non-reacting particles, including investigations of the laser-pulse–particle interaction. Subsequently, a single-shot evaluation approach was developed that enables quantitative determination of the elemental composition at the particle surface. The results show that picosecond laser pulses allow near-surface analysis of iron and iron oxide particles and that the oxygen-to-iron ratio can be reliably determined. By applying the method to first reacting iron particles, the work demonstrates the suitability of the developed diagnostic approach for investigating thermochemically oxidizing iron particles. It thus makes an important contribution to the fundamental understanding of the underlying chemical and physical processes, as well as to the development and validation of future models for sustainable, metal-based energy storage systems.

Maximilian Dorscht would like to express his sincere gratitude for the wonderful time he spent with his colleagues at RSM, ODEE, and Clean Circles. Their willingness to help each other, in particular, contributed significantly to the success of his dissertation.