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8 results on '"Lohse, Leon"'

1. X-ray nanotomography uncovers morphological heterogeneity in a polymerization catalyst at multiple reaction stages

Author

Werny, Maximilian J., Valadian, Roozbeh, Lohse, Leon M., Robisch, Anna Lena, Zanoni, Silvia, Hendriksen, Coen, Weckhuysen, Bert M., Meirer, Florian, Werny, Maximilian J., Valadian, Roozbeh, Lohse, Leon M., Robisch, Anna Lena, Zanoni, Silvia, Hendriksen, Coen, Weckhuysen, Bert M., and Meirer, Florian

Abstract

During olefin polymerization on supported catalysts, the controlled morphological evolution of the catalyst particle is vital for ensuring optimal product properties and high catalyst activity. We employed non-destructive hard X-ray holotomography to quantitatively assess the 3D morphology of multiple silica-supported hafnocene-based catalyst particles during the early stages of gas-phase ethylene polymerization. Image processing and pore network modeling revealed clear variations in the dimensions and interconnectivity of pristine particles' macropore networks. This, together with apparent differences in the fragmentation behavior of pre-polymerized particles, suggests that the reactivity and morphological evolution of individual particles are largely dictated by their unique support and pore space architectures. By minimizing the structural heterogeneity among pristine catalyst particles, more uniform particle morphologies may be obtained. Significant polymerization activity, observed in the particles' interiors, further implies that appropriate polymerization conditions and catalyst kinetics can guarantee sufficiently high particle accessibilities and thus more homogeneous support fragmentation.

Published
2021

2. 3-D X-ray Nanotomography Reveals Different Carbon Deposition Mechanisms in a Single Catalyst Particle

Author

Veselý, Martin, Valadian, Roozbeh, Merten Lohse, Leon, Toepperwien, Mareike, Spiers, Kathryn, Garrevoet, Jan, Vogt, Eelco T. C., Salditt, Tim, Weckhuysen, Bert M., Meirer, Florian, Veselý, Martin, Valadian, Roozbeh, Merten Lohse, Leon, Toepperwien, Mareike, Spiers, Kathryn, Garrevoet, Jan, Vogt, Eelco T. C., Salditt, Tim, Weckhuysen, Bert M., and Meirer, Florian

Abstract

Catalyst deactivation involves a complex interplay of processes taking place at different length and time scales. Understanding this phenomenon is one of the grand challenges in solid catalyst characterization. A process contributing to deactivation is carbon deposition (i.?e., coking), which reduces catalyst activity by limiting diffusion and blocking active sites. However, characterizing coke formation and its effects remains challenging as it involves both the organic and inorganic phase of the catalytic process and length scales from the atomic scale to the scale of the catalyst body. Here we present a combination of hard X-ray imaging techniques able to visualize in 3-D the distribution, effect and nature of carbon deposits in the macro-pore space of an entire industrially used catalyst particle. Our findings provide direct evidence for coke promoting effects of metal poisons, pore clogging by coke, and a correlation between carbon nature and its location. These results provide a better understanding of the coking process, its relation to catalyst deactivation and new insights into the efficiency of the industrial scale process of fluid catalytic cracking.

Published
2021

3. 3-D X-ray Nanotomography Reveals Different Carbon Deposition Mechanisms in a Single Catalyst Particle

Author

Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Veselý, Martin, Valadian, Roozbeh, Merten Lohse, Leon, Toepperwien, Mareike, Spiers, Kathryn, Garrevoet, Jan, Vogt, Eelco T. C., Salditt, Tim, Weckhuysen, Bert M., Meirer, Florian, Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Veselý, Martin, Valadian, Roozbeh, Merten Lohse, Leon, Toepperwien, Mareike, Spiers, Kathryn, Garrevoet, Jan, Vogt, Eelco T. C., Salditt, Tim, Weckhuysen, Bert M., and Meirer, Florian

Published
2021

4. 3-D X-ray Nanotomography Reveals Different Carbon Deposition Mechanisms in a Single Catalyst Particle

Author

Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Veselý, Martin, Valadian, Roozbeh, Merten Lohse, Leon, Toepperwien, Mareike, Spiers, Kathryn, Garrevoet, Jan, Vogt, Eelco T. C., Salditt, Tim, Weckhuysen, Bert M., Meirer, Florian, Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Veselý, Martin, Valadian, Roozbeh, Merten Lohse, Leon, Toepperwien, Mareike, Spiers, Kathryn, Garrevoet, Jan, Vogt, Eelco T. C., Salditt, Tim, Weckhuysen, Bert M., and Meirer, Florian

Published
2021

5. 3-D X-ray Nanotomography Reveals Different Carbon Deposition Mechanisms in a Single Catalyst Particle

Author

Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Veselý, Martin, Valadian, Roozbeh, Merten Lohse, Leon, Toepperwien, Mareike, Spiers, Kathryn, Garrevoet, Jan, Vogt, Eelco T. C., Salditt, Tim, Weckhuysen, Bert M., Meirer, Florian, Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Veselý, Martin, Valadian, Roozbeh, Merten Lohse, Leon, Toepperwien, Mareike, Spiers, Kathryn, Garrevoet, Jan, Vogt, Eelco T. C., Salditt, Tim, Weckhuysen, Bert M., and Meirer, Florian

Published
2021

6. 3-D X-ray Nanotomography Reveals Different Carbon Deposition Mechanisms in a Single Catalyst Particle

Author

Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Veselý, Martin, Valadian, Roozbeh, Merten Lohse, Leon, Toepperwien, Mareike, Spiers, Kathryn, Garrevoet, Jan, Vogt, Eelco T. C., Salditt, Tim, Weckhuysen, Bert M., Meirer, Florian, Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Veselý, Martin, Valadian, Roozbeh, Merten Lohse, Leon, Toepperwien, Mareike, Spiers, Kathryn, Garrevoet, Jan, Vogt, Eelco T. C., Salditt, Tim, Weckhuysen, Bert M., and Meirer, Florian

Published
2021

7. 3-D X-ray Nanotomography Reveals Different Carbon Deposition Mechanisms in a Single Catalyst Particle

Author

Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Veselý, Martin, Valadian, Roozbeh, Merten Lohse, Leon, Toepperwien, Mareike, Spiers, Kathryn, Garrevoet, Jan, Vogt, Eelco T. C., Salditt, Tim, Weckhuysen, Bert M., Meirer, Florian, Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Veselý, Martin, Valadian, Roozbeh, Merten Lohse, Leon, Toepperwien, Mareike, Spiers, Kathryn, Garrevoet, Jan, Vogt, Eelco T. C., Salditt, Tim, Weckhuysen, Bert M., and Meirer, Florian

Published
2021

8. 3-D X-ray Nanotomography Reveals Different Carbon Deposition Mechanisms in a Single Catalyst Particle

Author

Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Veselý, Martin, Valadian, Roozbeh, Merten Lohse, Leon, Toepperwien, Mareike, Spiers, Kathryn, Garrevoet, Jan, Vogt, Eelco T. C., Salditt, Tim, Weckhuysen, Bert M., Meirer, Florian, Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Veselý, Martin, Valadian, Roozbeh, Merten Lohse, Leon, Toepperwien, Mareike, Spiers, Kathryn, Garrevoet, Jan, Vogt, Eelco T. C., Salditt, Tim, Weckhuysen, Bert M., and Meirer, Florian

Published
2021

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