A Multi-Nuclear MAS-NMR Study on the Structural Properties of Silicalite-1 Zeolite Synthesized Using N- and P-Based Organic Structure Directing Agents
[EN] The nature of organic structure directing agents (OSDAs) is of paramount importance in the final properties of zeolites, particularly the framework and porosity. Recently, the use of P-containing OSDAs has been employed for new zeolites, but there is little discussion compared to their analogue...
| Autores: | , , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2021 |
| País: | España |
| Institución: | Universitat Politècnica de València (UPV) |
| Repositorio: | RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia |
| Idioma: | inglés |
| OAI Identifier: | oai:riunet.upv.es:10251/182722 |
| Acceso en línea: | https://riunet.upv.es/handle/10251/182722 |
| Access Level: | acceso abierto |
| Palabra clave: | P-based OSDAs Zeolites Solid state MAS-NMR |
| Sumario: | [EN] The nature of organic structure directing agents (OSDAs) is of paramount importance in the final properties of zeolites, particularly the framework and porosity. Recently, the use of P-containing OSDAs has been employed for new zeolites, but there is little discussion compared to their analogues N-OSDAs. The main objective of this work is the characterization of pure silica MFI zeolite (silicalite-1) prepared by the dual-template route with tetrapropylammonium (TPA), tetrapropylphosphonium (TPP) cations, and mixtures thereof aiming to understand by advanced NMR methods how the nature of the organic influences the physico-chemical properties of the zeolite. Silicalite-1 has been successfully synthesized using the dual-template procedure with TPA and TPP molecules. Both OSDAs are incorporated into the zeolite without any specific preference, differently to that observed before for the TEA/TEP system, and homogenously mixed inside of the zeolite voids. The presence of TPP leads to the incorporation of less F, raising the concentration of Q(3)-defective sites in the silicalite-1 zeolites. Detailed NMR results indicate that those structural defects are close to the -CH3 group of the entrapped OSDAs in the zeolite and these defects consist of at least two silanol groups stabilizing the Si-O- species, which is responsible for the charge balancing. |
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