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

在气相中形成纳米颗粒，在化学气相合成（CVS）中，是一个动态过程，其细节只能通过原位方法详细阐明，特别是因为非常小的纳米颗粒可能在合成后发生转化，并且在非原位研究中可能丢失关键信息。在该项目中，首次将X射线散射方法-小角和广角散射-应用于研究CVS中的颗粒形成和转化。这也使得能够观察中间、瞬时和亚稳态-包括部分氧化-颗粒相。由于气相中的颗粒密度低，因此散射密度低，因此将这些方法应用于气相中的颗粒在实验上极具挑战性。然而，先进的同步辐射源，X射线探测器和我们的新的，移动的CVS反应堆使这些实验。

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.