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Rate and selectivity hysteresis during the carbon monoxide hydrogenation over promoted Co/MnOx catalysts

While cobalt-based catalysts have been used in industrial Fischer-Tropsch synthesis for decades, little is known about how the dynamics of the Co-Co(2)C phase transformation drive their performance. Here we report on the occurrence of hysteresis effects in the Fischer-Tropsch reaction over potassium...

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Autores principales: Xiang, Yizhi, Kovarik, Libor, Kruse, Norbert
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6718517/
https://www.ncbi.nlm.nih.gov/pubmed/31477697
http://dx.doi.org/10.1038/s41467-019-11836-z
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author Xiang, Yizhi
Kovarik, Libor
Kruse, Norbert
author_facet Xiang, Yizhi
Kovarik, Libor
Kruse, Norbert
author_sort Xiang, Yizhi
collection PubMed
description While cobalt-based catalysts have been used in industrial Fischer-Tropsch synthesis for decades, little is known about how the dynamics of the Co-Co(2)C phase transformation drive their performance. Here we report on the occurrence of hysteresis effects in the Fischer-Tropsch reaction over potassium promoted Co/MnO(x) catalyst. Both the reaction rate and the selectivity to chain-lengthened paraffins and terminally functionalized products (aldehydes, alcohols, olefins) show bistability when varying the hydrogen/carbon monoxide partial pressures back and forth from overall reducing to carbidizing conditions. While the carbon monoxide conversion and the selectivity to functionalized products follow clockwise hysteresis, the selectivity to paraffins shows counter-clockwise behavior. In situ X-ray diffraction demonstrates the activity/selectivity bistability to be driven by a Co-Co(2)C phase transformation. The conclusions are supported by High Resolution Transmission Electron Microscopy which identifies the Co-Co(2)C transformation, Mn(5)O(8) layered topologies at low H(2)/CO partial pressure ratios, and MnO at high such ratios.
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spelling pubmed-67185172019-09-04 Rate and selectivity hysteresis during the carbon monoxide hydrogenation over promoted Co/MnOx catalysts Xiang, Yizhi Kovarik, Libor Kruse, Norbert Nat Commun Article While cobalt-based catalysts have been used in industrial Fischer-Tropsch synthesis for decades, little is known about how the dynamics of the Co-Co(2)C phase transformation drive their performance. Here we report on the occurrence of hysteresis effects in the Fischer-Tropsch reaction over potassium promoted Co/MnO(x) catalyst. Both the reaction rate and the selectivity to chain-lengthened paraffins and terminally functionalized products (aldehydes, alcohols, olefins) show bistability when varying the hydrogen/carbon monoxide partial pressures back and forth from overall reducing to carbidizing conditions. While the carbon monoxide conversion and the selectivity to functionalized products follow clockwise hysteresis, the selectivity to paraffins shows counter-clockwise behavior. In situ X-ray diffraction demonstrates the activity/selectivity bistability to be driven by a Co-Co(2)C phase transformation. The conclusions are supported by High Resolution Transmission Electron Microscopy which identifies the Co-Co(2)C transformation, Mn(5)O(8) layered topologies at low H(2)/CO partial pressure ratios, and MnO at high such ratios. Nature Publishing Group UK 2019-09-02 /pmc/articles/PMC6718517/ /pubmed/31477697 http://dx.doi.org/10.1038/s41467-019-11836-z Text en © The Author(s) 2019 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
spellingShingle Article
Xiang, Yizhi
Kovarik, Libor
Kruse, Norbert
Rate and selectivity hysteresis during the carbon monoxide hydrogenation over promoted Co/MnOx catalysts
title Rate and selectivity hysteresis during the carbon monoxide hydrogenation over promoted Co/MnOx catalysts
title_full Rate and selectivity hysteresis during the carbon monoxide hydrogenation over promoted Co/MnOx catalysts
title_fullStr Rate and selectivity hysteresis during the carbon monoxide hydrogenation over promoted Co/MnOx catalysts
title_full_unstemmed Rate and selectivity hysteresis during the carbon monoxide hydrogenation over promoted Co/MnOx catalysts
title_short Rate and selectivity hysteresis during the carbon monoxide hydrogenation over promoted Co/MnOx catalysts
title_sort rate and selectivity hysteresis during the carbon monoxide hydrogenation over promoted co/mnox catalysts
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6718517/
https://www.ncbi.nlm.nih.gov/pubmed/31477697
http://dx.doi.org/10.1038/s41467-019-11836-z
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