A lab-scale method for the determination of the particle morphology of reactive metal oxide powders using X-ray scattering techniques

• rapid lab-scale metal fuel characterization using SWAXS • quantification of the increase of the specific surface area • observation of iron nucleation and growth Large-scale energy storage concepts are essential for the transition to renewable energy sources. Metal particles have recently gained significant attention as a viable solution due to their recyclability in large-scale energy storage systems. To ensure the material’s long-term durability, a thorough understanding of the interplay between particle properties and process conditions is imperative. This study demonstrates the applicability of lab-scale X-ray scattering techniques (SAXS/WAXS) as a quick and easy-to-apply method to investigate the morphology evolution of iron oxide particles during hydrogen reduction in a solid-gas heterogeneous reaction. The increase in the specific surface area could be quantified at various time points, after the reaction was temporarily interrupted without removing the powder from the reactor. The experimental setup, which involves an optically accessible reactor with reactive oxide particles embedded within a low-Z matrix, also enabled the characterization of iron nucleation and growth of iron nuclei up to 30 nm in size.