Multi-scale Chemical Imaging of Multi-component Catalyst Materials: New Opportunities to Understand Catalytic Activity and Related Deactivation Phenomena of Ziegler-Natta Catalysts
Heterogenous Ziegler-Natta catalysts have been the major workhorse in the production of polyolefins for decades. The heterogeneous Ziegler-Natta catalysts are multi-component hierarchically structured catalyst materials. These catalyst materials are made up of an activated MgCl2 support, TiCl4 (comprising the active site) and Lewis base species acting as donors. Such materials are build up from primary particles of 1-10 nm of MgCl2 with TiCl4 and the Lewis base species chemisorbed to the lateral lattices. These primary units build up spherical catalyst particles with typical size dimensions of 5-30 μm. Due to the complex hierarchical structure of the catalyst material combined with high sensitivity towards O2 and H2O there is a lack of knowledge on the 2D and 3D chemical structure of the catalyst material. The aim of this research is to use advanced chemical imaging methods such as scanning transmission x-ray microscopy (STXM) and transmission x-ray microscopy (TXM) combined with other advanced microscopy techniques working at different spatial resolutions and depths of focus to obtain spatially resolved chemical and structural information of both model and industrial heterogeneous Ziegler-Natta catalysts.