Assessment of the 3-D pore structure and individual components of preshaped catalyst bodies by X-ray imaging

Abstract

Porosity in catalyst particles is essential because it enables reactants to reach the active sites and it enables products to leave the catalyst. The engineering of composite-particle catalysts through the tuning of pore-size distribution and connectivity is hampered by the inability to visualize structure and porosity at critical-length scales. Herein, it is shown that the combination of phase-contrast X-ray microtomography and high-resolution ptychographic X-ray tomography allows the visualization and characterization of the interparticle pores at micro- and nanometer-length scales. Furthermore, individual components in preshaped catalyst bodies used in fluid catalytic cracking, one of the most used catalysts, could be visualized and identified. The distribution of pore sizes, as well as enclosed pores, which cannot be probed by traditional methods, such as nitrogen physisorption and isotherm analysis, were determined. Catalyst bodies in 3-D: The assessment of the 3-D pore structure and components of catalyst bodies in the nanoscale is crucial to understand the fluid catalytic-cracking process (FCC). Modern X-ray imaging techniques allow visualization and quantification of the 3-D pore structure, as well as the material components of FCC catalyst bodies, at this critical scale. These techniques help to improve the manufacture of these catalyst bodies by tuning the pore size and connectivity in a controlled manner.