ChemRxiv
These are preliminary reports that have not been peer-reviewed. They should not be regarded as conclusive, guide clinical practice/health-related behavior, or be reported in news media as established information. For more information, please see our FAQs.
1/1
2 files
0/0

Synthesis, Characterization, and Post-Synthetic Modification of a Micro/Mesoporous Zirconium-Tricarboxylate Metal-Organic Framework: Towards the Addition of Acid Active Sites

preprint
submitted on 14.02.2019 and posted on 15.02.2019 by Carolina Ardila-Suárez, Ana María Díaz-Lasprilla, Laura Alejandra Díaz Vaca, Perla B Balbuena, Víctor Gabriel Baldovino Medrano, Gustavo E Ramírez-Caballero

Zr-MOFs are characterized by their high thermal and chemical stability which may facilitate their application in heterogeneous catalysis. However, these well-known microporous materials could see restricted their applications in heterogeneous catalysis if large reactants exceed their pore sizes leading to unavailable surface areas. In this work, we studied the effect of acetic acid concentration, used as the modulator, on the formation of micro/mesoporous materials. This inclusion of a modulator during synthesis and its removal by activation process generate materials with missing linker defects. We showed that an increase in the concentration of modulator leads to an improvement of calculated apparent surface area and a modification of MOF-808 pore structure by producing mesopores at the expense of micropores. Furthermore, we performed a post-synthetic modification of the MOF-808. We observed the expected sulfation of the zirconium oxo-cluster but also the sulfonation of the organic ligand. Also, we found that only the families of mesopores and the larger micropores are interconnected within the material, and the ultramicropores seems to be isolated from the porous structure. The PSM process led to the addition of Lewis and Brønsted acid sites to the MOF-808. Experimental results were complemented by theoretical calculations using Density Functional Theory (DFT) and Ab Initio Molecular Dynamics (AIMD) simulations. The rationalization of the synthesis conditions effect and the post-synthetic sulfation process on final properties presented in this paper can serve as a basis for engineering of defects towards the synthesis of solid acid catalysts from MOF 808.


Funding

Vicerrectoría de Investigación y Extensión (VIE) at Universidad Industrial de Santander (UIS) through the agreement of cooperation (code 9457) between UIS University and Fundación para la Promoción de la Investigación y la Tecnología, FPIT. C.

History

Email Address of Submitting Author

carolina.ardila@correo.uis.edu.co

Institution

Universidad Industrial de Santander

Country

Colombia

ORCID For Submitting Author

0000-0001-8649-2218

Declaration of Conflict of Interest

There are no conflicts to declare

Exports