Mapping Metals Incorporation of a Whole Single Catalyst Particle Using Element Specific X-ray Nanotomography

Abstract

Full-field transmission X-ray microscopy has been used to determine the 3D structure of a whole individual fluid catalytic cracking (FCC) particle at high spatial resolution and in a fast, noninvasive manner, maintaining the full integrity of the particle. Using X-ray absorption mosaic imaging to combine multiple fields of view, computed tomography was performed to visualize the macropore structure of the catalyst and its availability for mass transport. We mapped the relative spatial distributions of Ni and Fe using multiple-energy tomography at the respective X-ray absorption K-edges and correlated these distributions with porosity and permeability of an equilibrated catalyst (E-cat) particle. Both metals were found to accumulate in outer layers of the particle, effectively decreasing porosity by clogging of pores and eventually restricting access into the FCC particle.

Relating structure and composition with accessibility of a single catalyst particle using correlative 3-dimensional micro-spectroscopy

“…1, the morphological information obtained by nano-TXM is displayed. The particle appears to be a typical FCC catalyst particle when compared with previous studies181920212941: it has a diameter of about 40 μm, shows a denser surface layer of 1–2 μm thickness and a complex macro-pore structure throughout the rest of the particle; the total porosity was determined to 18.8%. In this study, we additionally performed a pore throat analysis45, which revealed a pore throat size distribution peak at about 320 nm.…”

Tailoring and visualizing the pore architecture of hierarchical zeolites

“…Furthermore, no information about size and shape of the mesopores can be obtained because the resolution is limited. [171][172][173] Recently, Mitchell et al used synchrotron radiation X-ray tomography microscopy (SRXTM) to visualize the internal pore architecture of an industrial granule consisting of hierarchical alkaline-treated ZSM-5 zeolite and the binder attapulgite. Besides imaging porosity, the recently developed optical method based on microimaging by interference and infrared microscopy was successfully used to monitor diffusion of non-fluorescent guest molecules, such as methanol and ethanol, through nanoporous zeolites.…”

Operando XAFS Imaging of Distribution of Pt Cathode Catalysts in PEFC MEA

“…For example, B. M. Weckhuysen, et al. reported a method for investigating three‐dimensional morphology and heavy metal poisoning of individual catalyst particles for fluid catalytic cracking (FCC) using TXM‐tomography technique at multiple absorption edges and revealed the interaction of porosity and elemental distribution changes in the catalyst . J.…”