The nature of active Ni sites and the role of Al species in the oligomerization of ethylene on mesoporous Ni-Al-MCM-41 catalysts
| العنوان: | The nature of active Ni sites and the role of Al species in the oligomerization of ethylene on mesoporous Ni-Al-MCM-41 catalysts |
|---|---|
| المؤلفون: | Agustín Martínez, Patricia Concepción, MA Arribas, Sara Moussa |
| المساهمون: | Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España) |
| المصدر: | Digital.CSIC. Repositorio Institucional del CSIC instname RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia |
| بيانات النشر: | Elsevier BV, 2020. |
| سنة النشر: | 2020 |
| مصطلحات موضوعية: | Ethylene, biology, 010405 organic chemistry, Process Chemistry and Technology, Ni-Al-MCM-41 catalysts, 010402 general chemistry, biology.organism_classification, 01 natural sciences, Catalysis, 0104 chemical sciences, chemistry.chemical_compound, chemistry, Chemical engineering, MCM-41, Ethylene oligomerization, Mesoporous material, Valencia, Active nickel sites, Role of Al species |
| الوصف: | [EN] Although nickel dispersed in mesoporous aluminosilicates are efficient catalysts for the oligomerization of ethylene, the nature of the active nickel sites still remains controversial. Here we applied in situ FTIR-CO spectroscopy during reaction with ethylene combined with reaction kinetics with online MS analysis of reaction products to unravel the nature of the active nickel species in working mesoporous Ni-Al-MCM-41 catalysts. The results revealed that isolated ion-exchanged Ni2+ cations are irreversibly blocked during the initial reaction stages leaving unsaturated Ni2+ cations grafted on silanols and at the surface of small (confined) NiO nanoparticles as the active species in the pseudo-steady state. The low activity of these species in pure silica materials suggested a promotional role of aluminum in the Al-MCM-41 matrix on enhancing the activity of Ni2+ sites, probably through a close interaction between Al species and nearby Ni2+ sites, as inferred from quantitative Al-27 MAS NMR and FTIR spectroscopies This work has been financially supported by the Spanish government through the Severo Ochoa Program (SEV2016-0683) and RTI2018-102161 projects. The authors acknowledge the Microscopy Service of the Universitat Politecnica de Valencia for its assistance in the characterization of materials by electron microscopy. |
| وصف الملف: | application/pdf |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::5e7d1d7267b68a8089f50bd9feabc449 http://hdl.handle.net/10261/224951 |
| حقوق: | OPEN |
| رقم الأكسشن: | edsair.doi.dedup.....5e7d1d7267b68a8089f50bd9feabc449 |
| قاعدة البيانات: | OpenAIRE |
| الوصف غير متاح. |