Architecture‐Dependent Distribution of Mesopores in Steamed Zeolite Crystals as Visualized by FIB‐SEM Tomography

Karwacki, Łukasz; Winter, D. A. Matthijs de; Aramburo, Luis R.; Lebbink, Misjaël N.; Post, Jan Andries; Drury, Martyn; Weckhuysen, Bert M.

doi:10.1002/ange.201006031

Cited by 23 publications

(32 citation statements)

References 36 publications

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“…In this regard, nothing is more tangible than the direct visualization of the pore architecture 75 . Compared with bulk zeolites, where microscopic techniques are primarily used to determine the particle size and morphology, the multidimensional challenge of examining the structural organization in HOZs has fuelled the development of much more advanced imaging approaches 66 72 76 77 . Fronting this movement, de Jong et al elegantly exemplified the 3D TEM tomographic reconstruction and quantitative analysis of the pore network within commercial USY zeolite crystals 66 76 .…”

Section: Pore Architecturementioning

confidence: 99%

Structural analysis of hierarchically organized zeolites

et al. 2015

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Section: Pore Architecturementioning

confidence: 99%

Structural analysis of hierarchically organized zeolites

et al. 2015

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“…Deactivation processes taking place in the FCCU were previously studied by visualization of the structural alterations of the catalyst particle and the zeolite crystal itself, employing various high-resolution imaging techniques. Examples include atomic force microscopy (AFM), [4][5][6] scanning electron microscopy (SEM), [7][8][9][10][11][12] and transmission electron microscopy (TEM). [13][14][15][16][17] These methods provide high-resolution detail, but no correlation was possible between the structure and the activity of the investigated catalyst particles.…”

Section: Introductionmentioning

confidence: 99%

Probing the Different Life Stages of a Fluid Catalytic Cracking Particle with Integrated Laser and Electron Microscopy

Karreman

Buurmans

Agronskaia

et al. 2013

Chemistry A European J

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While cycling through a fluid catalytic cracking (FCC) unit, the structure and performance of FCC catalyst particles are severely affected. In this study, we set out to characterize the damage to commercial equilibrium catalyst particles, further denoted as ECat samples, and map the different pathways involved in their deactivation in a practical unit. The degradation was studied on a structural and a functional level. Transmission electron microscopy (TEM) of ECat samples revealed several structural features; including zeolite crystals that were partly or fully severed, mesoporous, macroporous, and/or amorphous. These defects were then correlated to structural features observed in FCC particles that were treated with different levels of hydrothermal deactivation. This allowed us not only to identify which features observed in ECat samples were a result of hydrothermal deactivation, but also to determine the severity of treatments resulting in these defects. For functional characterization of the ECat sample, the Brønsted acidity within individual FCC particles was studied by a selective fluorescent probe reaction with 4-fluorostyrene. Integrated laser and electron microscopy (iLEM) allowed correlating this Brønsted acidity to structural features by combining a fluorescence and a transmission electron microscope in a single set-up. Together, these analyses allowed us to postulate a plausible model for the degradation of zeolite crystals in FCC particles in the ECat sample. Furthermore, the distribution of the various deactivation processes within particles of different ages was studied. A rim of completely deactivated zeolites surrounding each particle in the ECat sample was identified by using iLEM. These zeolites, which were never observed in fresh or steam-deactivated samples, contained clots of dense structures. The structures are proposed to be carbonaceous deposits formed during the cracking process, and seem resistant towards burning off during catalyst regeneration.

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“…Reconstructed models use recent advances in microscopy, enabling three-dimensional imaging of the porous catalytic materials at high resolution [10][11][12][13][14]. Methods for high-resolution microscopy include X-ray tomography [15][16][17][18][19][20] or FIB-SEM techniques [21][22][23][24][25][26] to reconstruct the microporous structure of the catalysts. The images are also used to explore the influence of the reaction rates and effective diffusions within the porous media, improve the accuracy of the chemical-kinetic models, and optimize the design of the washcoat structure [27].…”

Section: Prior Researchmentioning

confidence: 99%

“…Although FIB-SEM techniques have been used to characterize a variety of samples [13,14,[28][29][30][31][32][33][34][35][36], the application of this technique on highly porous media is relatively new and challenging. Prill et al [37,38] used a FIB-SEM technique for 3D reconstruction of a highly porous media and reported that, unlike the batteries and dense surfaces with less porosity, the interpretation of the FIB-SEM data are quite difficult due to the "shine-through" artifacts.…”

Section: Prior Researchmentioning

confidence: 99%

Modeling reaction–diffusion processes within catalyst washcoats: I. Microscale processes based on three-dimensional reconstructions

Karakaya¹,

Weddle²,

Blasi³

et al. 2016

Chemical Engineering Science

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This paper develops a detailed analysis of reaction-diffusion processes within a porous rhodium-alumina catalyst washcoat. Focused-ion-beam-scanningelectron-microscope (FIB-SEM) techniques are developed and applied to reconstruct the actual catalyst-support microstructure. Three-dimensional transport processes within washcoat micro-pore structures are modeled using a dimensionless representation of reaction and diffusion rates based on the Damköhler number. Three-dimensional computational solutions for particular porous microstructures are modeled and interpreted. In a companion paper, these microstructural results are used to assist development of largerscale models that can be incorporated into reactor-scale simulations.

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Architecture‐Dependent Distribution of Mesopores in Steamed Zeolite Crystals as Visualized by FIB‐SEM Tomography

Cited by 23 publications

References 36 publications

Structural analysis of hierarchically organized zeolites

Structural analysis of hierarchically organized zeolites

Probing the Different Life Stages of a Fluid Catalytic Cracking Particle with Integrated Laser and Electron Microscopy

Modeling reaction–diffusion processes within catalyst washcoats: I. Microscale processes based on three-dimensional reconstructions

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