Kontrolle der Oxidationsstufe von Eisen in Nanopartikeln aus Eisenoxiden und Eisen-Kohlenstoff-Kompositen in der chemischen Gasphasensynthese

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Formation of nanoparticles in the gas phase, here in chemical vapor synthesis (CVS), is a dynamic process the details of which can only be elucidated in detail by in situ methods, especially since the very small nanoparticles may transform after synthesis and crucial information may be lost in ex situ studies. In this project for the first time X-ray scattering methods – small and wide angle scattering – will be applied to investigate particle formation and transformation in CVS. This enables also the observation of intermediate, transient and metastable – including partially oxidized – particle phases. The application of these methods to particles in the gas phase is experimentally highly challenging because of the low particle density in the gas phase and, therefore, low scattering density. However, advanced synchrotron radiation sources, X-ray detectors and our novel, mobile CVS-reactor enable these experiments.