(493b) “Advanced” Materials Characterization of Catalysts at BASF

Materials characterization is a core part of catalysts development at BASF. Characterizing our catalyst materials helps to understand what specifically affects catalyst performance to aid in improving and developing better catalysts. This presentation highlights some of the “advanced” materials characterization studies undergone at BASF using both spectroscopy and microscopy.

X-ray spectroscopy was employed to observe the evolution of Cu species in Cu-exchanged zeolite catalysts under steam and selective catalytic reduction(SCR) conditions. Utilizing synchrotron facilities, Near Ambient Pressure X-ray Photoelectron Spectroscopy(NAP-XPS) and X-ray Absorption Spectroscopy(XAS) uncover critical chemical state and local atomic structural changes during these processes that take place over catalysts responsible for emission control in diesel vehicles. NAP-XPS shows the migration of copper to exchange sites inside zeolite cages during steam treatment. In-situ XAS shows the transformation of Cu species during the SCR reaction. These complimentary spectroscopic techniques were used to provide clearer insight into the evolution of exchanged Cu species under these reaction conditions.

X-ray Micro-Tomography(XMT) and Deep Learning(DL) was utilized to visualize Four-Way Catalyst(FWC) filters via 3D imaging and quantification to correlate microstructural features with backpressure. FWC catalysts provide three-way conversion efficiency and filtration of particulate matter simultaneously, which is required in emission control as restrictions get tighter. Backpressure generated by an FWC catalyst becomes a concern and has to be carefully controlled. 3D morphology of the FWC catalyst is suspected to have the largest effect on backpressure. XMT allows 3D imaging, which provides relevant information with respect to the 3D morphology of filters. DL allows segmentation to occur in hours, which otherwise takes days. By imaging/analyzing filters with increasing washcoat loading, we correlate what morphological features are affected by increased loading and correlate that to backpressure changes. This helps us facilitate rational design by understanding how different coating parameters affect the 3D morphology and ultimately performance.