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.

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.…”

Advances and challenges in cryo ptychography at the Advanced Photon Source

“…As the transverse resolution improves, the depth of field decreases with the square of these improvements, putting a limit on the sample thickness for straightforward interpretation. The red curve is the DOF limit at 6.2 keV, the energy of ptychographic tomography demonstrations (red dots; see [11, 27, 4, 28, 12, 29, 30, 31, 32]) at the cSAXS beamline at the Swiss Light Source routinely conduct the 3D ptychography. The blue dot represents our fly-scan 3D ptychography study (Fig.…”

Ptychographic nanotomography at the Swiss Light Source

“…11,12 Recent applications of PXCT at SLS include the use of the complex-valued index of refraction to quantify the mass density and water content of calcium silicate hydrates (CSH), 13 which are the most abundant hydration products in ordinary Portland cement paste, to quantify the mineral distribution on human dentine, 14 and for characterization of the nanoporous network of catalyst particles. 15 Novel extensions of the technique have demonstrated element-specific three-dimensional imaging via resonant phase tomography 16 and recovery of quantitative contrast for interior tomography by combination with a low-resolution overview. 17 Ptychographic nanotomography has also been demonstrated for in situ measurements to study silk fiber hydration under varying humidity 18 and quantify the densification and fracture of a microcomposite undercompression.…”