Mayenite-Based Electride C12A7e<sup>−</sup>: A Reactivity and Stability Study
Ru supported on mayenite electride, [Ca<sub>24</sub>Al<sub>28</sub>O<sub>64</sub>]<sup>4+</sup>(e<sup>−</sup>)<sub>4</sub> a calcium aluminum oxide denoted as C12A7e<sup>−</sup>, are described in the literature as hi...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-03-01
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| Series: | Catalysts |
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| Online Access: | https://www.mdpi.com/2073-4344/11/3/334 |
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| author | Sebastian Weber Sebastian Schäfer Mattia Saccoccio Nils Ortner Marko Bertmer Karsten Seidel Stefan Berendts Martin Lerch Roger Gläser Holger Kohlmann Stephan A. Schunk |
| author_facet | Sebastian Weber Sebastian Schäfer Mattia Saccoccio Nils Ortner Marko Bertmer Karsten Seidel Stefan Berendts Martin Lerch Roger Gläser Holger Kohlmann Stephan A. Schunk |
| author_sort | Sebastian Weber |
| collection | DOAJ |
| description | Ru supported on mayenite electride, [Ca<sub>24</sub>Al<sub>28</sub>O<sub>64</sub>]<sup>4+</sup>(e<sup>−</sup>)<sub>4</sub> a calcium aluminum oxide denoted as C12A7e<sup>−</sup>, are described in the literature as highly active catalysts for ammonia synthesis, especially under conditions of low absolute pressure. In this study, we investigated the application of recently reported plasma arc melting synthesized C12A7e<sup>−</sup> (aluminum solid reductant) as supports of Ru/C12A7e<sup>−</sup> catalysts in ammonia synthesis up to pressures of 7.6 MPa. Together with the plasma-arc-melting-based catalyst support, we investigated a similar plasma-synthesized C12A7e<sup>−</sup> (graphite solid reductant) and a vacuum-sintering-based C12A7e<sup>−</sup>. Complementary to the catalytic tests, we applied <sup>2</sup>H solid-state NMR spectroscopy, DRUVVis-spectroscopy, thermal analysis and PXRD to study and characterize the reactivity of different plasma-synthesized and vacuum-sintered C12A7e<sup>−</sup> towards H<sub>2</sub>/D<sub>2</sub> and H<sub>2</sub>O. The catalysts showed an immediate deactivation at pressures > 1 MPa, which can be explained by irreversible hydride formation at higher pressures, as revealed by reactivity tests of C12A7e<sup>−</sup> towards H<sub>2</sub>/D<sub>2</sub>. The direct formation of C12A7:D from C12A7e<sup>−</sup> is proven. It can be concluded that the application of Ru/C12A7e<sup>−</sup> catalysts at the industrial scale has limited prospects due to irreversible hydride formation at relevant pressures > 1 MPa. Furthermore, we report an in-depth study relating to structural changes in the material in the presence of H<sub>2</sub>O. |
| first_indexed | 2024-03-09T05:19:43Z |
| format | Article |
| id | doaj.art-ee67164d58e44c44a1dfde8a3f1dec20 |
| institution | Directory Open Access Journal |
| issn | 2073-4344 |
| language | English |
| last_indexed | 2024-03-09T05:19:43Z |
| publishDate | 2021-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Catalysts |
| spelling | doaj.art-ee67164d58e44c44a1dfde8a3f1dec202023-12-03T12:42:45ZengMDPI AGCatalysts2073-43442021-03-0111333410.3390/catal11030334Mayenite-Based Electride C12A7e<sup>−</sup>: A Reactivity and Stability StudySebastian Weber0Sebastian Schäfer1Mattia Saccoccio2Nils Ortner3Marko Bertmer4Karsten Seidel5Stefan Berendts6Martin Lerch7Roger Gläser8Holger Kohlmann9Stephan A. Schunk10hte GmbH, Kurpfalzring 104, 69123 Heidelberg, Germanyhte GmbH, Kurpfalzring 104, 69123 Heidelberg, Germanyhte GmbH, Kurpfalzring 104, 69123 Heidelberg, GermanyLeibniz Institute for Catalysis (LIKAT Rostock), Albert-Einstein-Straße 29a, 18059 Rostock, GermanyFelix-Bloch-Institut für Festkörperphysik, Leipzig University, Linnéstraße 5, 04103 Leipzig, GermanyBASF SE, Carl-Bosch-Straße 38, 67056 Ludwigshafen am Rhein, GermanyInstitute of Chemistry, TU Berlin, Straße des 17. Juni 135, 10623 Berlin, GermanyInstitute of Chemistry, TU Berlin, Straße des 17. Juni 135, 10623 Berlin, GermanyInstitute of Chemical Technology, Leipzig University, Linnéstraße 3, 04103 Leipzig, GermanyInstitute of Inorganic Chemistry, Leipzig University, Johannisallee 29, 04103 Leipzig, Germanyhte GmbH, Kurpfalzring 104, 69123 Heidelberg, GermanyRu supported on mayenite electride, [Ca<sub>24</sub>Al<sub>28</sub>O<sub>64</sub>]<sup>4+</sup>(e<sup>−</sup>)<sub>4</sub> a calcium aluminum oxide denoted as C12A7e<sup>−</sup>, are described in the literature as highly active catalysts for ammonia synthesis, especially under conditions of low absolute pressure. In this study, we investigated the application of recently reported plasma arc melting synthesized C12A7e<sup>−</sup> (aluminum solid reductant) as supports of Ru/C12A7e<sup>−</sup> catalysts in ammonia synthesis up to pressures of 7.6 MPa. Together with the plasma-arc-melting-based catalyst support, we investigated a similar plasma-synthesized C12A7e<sup>−</sup> (graphite solid reductant) and a vacuum-sintering-based C12A7e<sup>−</sup>. Complementary to the catalytic tests, we applied <sup>2</sup>H solid-state NMR spectroscopy, DRUVVis-spectroscopy, thermal analysis and PXRD to study and characterize the reactivity of different plasma-synthesized and vacuum-sintered C12A7e<sup>−</sup> towards H<sub>2</sub>/D<sub>2</sub> and H<sub>2</sub>O. The catalysts showed an immediate deactivation at pressures > 1 MPa, which can be explained by irreversible hydride formation at higher pressures, as revealed by reactivity tests of C12A7e<sup>−</sup> towards H<sub>2</sub>/D<sub>2</sub>. The direct formation of C12A7:D from C12A7e<sup>−</sup> is proven. It can be concluded that the application of Ru/C12A7e<sup>−</sup> catalysts at the industrial scale has limited prospects due to irreversible hydride formation at relevant pressures > 1 MPa. Furthermore, we report an in-depth study relating to structural changes in the material in the presence of H<sub>2</sub>O.https://www.mdpi.com/2073-4344/11/3/334mayeniteelectridecalcium aluminatescatalyst supportrutheniumammonia synthesis |
| spellingShingle | Sebastian Weber Sebastian Schäfer Mattia Saccoccio Nils Ortner Marko Bertmer Karsten Seidel Stefan Berendts Martin Lerch Roger Gläser Holger Kohlmann Stephan A. Schunk Mayenite-Based Electride C12A7e<sup>−</sup>: A Reactivity and Stability Study Catalysts mayenite electride calcium aluminates catalyst support ruthenium ammonia synthesis |
| title | Mayenite-Based Electride C12A7e<sup>−</sup>: A Reactivity and Stability Study |
| title_full | Mayenite-Based Electride C12A7e<sup>−</sup>: A Reactivity and Stability Study |
| title_fullStr | Mayenite-Based Electride C12A7e<sup>−</sup>: A Reactivity and Stability Study |
| title_full_unstemmed | Mayenite-Based Electride C12A7e<sup>−</sup>: A Reactivity and Stability Study |
| title_short | Mayenite-Based Electride C12A7e<sup>−</sup>: A Reactivity and Stability Study |
| title_sort | mayenite based electride c12a7e sup sup a reactivity and stability study |
| topic | mayenite electride calcium aluminates catalyst support ruthenium ammonia synthesis |
| url | https://www.mdpi.com/2073-4344/11/3/334 |
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