Hu, S;
Liu, J;
Ye, G;
Zhou, X;
Coppens, M-O;
Yuan, W;
(2021)
Effect of External Surface Diffusion Barriers on Pt/Beta Catalyzed Isomerization of n-Pentane.
Angewandte Chemie International Edition
10.1002/anie.202104859.
(In press).
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Abstract
Zeolite crystals contain transport barriers on their external surface that hinder molecular uptake and processes that depend on it, such as catalysis and separations. However, the potentially dominant role of surface barriers in such processes is only emerging. In this work, we have developed a generalizable strategy to quantify the effect of surface barriers on zeolite catalysis. Isomerization of n -pentane, catalyzed by Pt/Beta, is taken as a model reaction system. Firstly, the surface modification by chemical liquid deposition of SiO 2 was carried out to control the surface barriers on zeolite Beta crystals. The deposition of SiO 2 leads to a very slight change in the physical properties of Beta crystals, but an obvious reduction in Brønsted acid sites. Diffusion measurements by the zero-length column (ZLC) method show that the apparent diffusivity of n -pentane can be more than doubled after SiO 2 deposition, indicating that the surface barriers have been weakened. Catalytic performance was tested in a fixed-bed reactor, showing that the apparent catalytic activity improved by 51-131% after SiO 2 deposition. These results provide direct proof that reducing surface barriers can be an effective route to improve zeolite catalyst performance deteriorated by transport limitations.
| Type: | Article |
|---|---|
| Title: | Effect of External Surface Diffusion Barriers on Pt/Beta Catalyzed Isomerization of n-Pentane |
| Location: | Germany |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1002/anie.202104859 |
| Publisher version: | https://doi.org/10.1002/anie.202104859 |
| Language: | English |
| Additional information: | This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ |
| Keywords: | diffusion, isomerization, surface barriers, surface modification, zeolite Beta |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Chemical Engineering |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10128225 |
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