|
|
| Identifier |
000352167 |
| Title |
Μελέτη προσρόφησης υδρογόνου σε νανοδομημένα υλικά |
| Alternative Title |
Studies of hydrogen absorption in novel nanostructured materials |
|
Author
|
Κλώντζας, Εμμανουήλ Μ.
|
|
Thesis advisor
|
Φρουδάκης, Γεώργιος
|
| Abstract |
In the present PhD thesis we have studied the hydrogen storage performance of IsoReticular Metal-Organic Frameworks (IRMOF) and Covalent-Organic Frameworks (COF), using various theoretical methods and computational techniques.
IRMOF and COF materials have been proposed as hydrogen storage materials from the first time that they were synthesized, due to their unique physicochemical and structural properties.
Firstly we studied IRMOF materials for hydrogen storage. Preliminary results had shown that hydrogen was interacting with these materials by weak van der Waals
interactions. It was proposed that the enhancement of the interaction strength would lead to a better hydrogen storage performance of these materials. One way to do that
is the introduction of point charges into the material, which can be done by decorating the pore with Li atoms. Li atoms can be incorporated either by interacting with the aromatic systems of the structures or by the formation of –SO3Li and –OLi groups.
We have studied the last two cases by using first principles computational methods and we have found that the interaction strength was enhanced in the modified IRMOF materials by a factor of three. Further investigation by performing GCMC simulations
showed that there was also an enhancement of the total hydrogen storage abilities of these materials both at cryogenic and room temperature.
Next we have evaluated the hydrogen storage abilities of the 3D-COF family of
materials. We have performed first principles calculations on these materials to study
the interaction of hydrogen with the individual building blocks that these materials
were made from. We found that hydrogen interacted with the material by weak van
der Waals and dispersion forces, where the strength of these interactions was similar
to those of IRMOF. GCMC simulations showed that these materials had exceptional
hydrogen storage capacities. The best of these materials was COF-105, which reach
20 %wt at 77K and 100bar, which was by far the best performed known material in
the field. In order to increase the hydrogen storage ability of these materials, we have
introduced –OLi groups in the structure of the best performed COF-105. We found an
enhancement in both the interactions of the hydrogen with the material and of the total
hydrogen amount that could be stored in these materials. Finally, we have designed
new 3D-COF materials based on ctn network and by using the connectivity of COF-
102. These new COF were firstly optimized by molecular mechanics method with the
use of an appropriate modified MM3 forcefield and then their storage abilities were
investigated by GCMC simulations. We found that the best of the materials that we
designed could exhibit 27 %wt at 77K and 100bar, well above the best performed
COF-105.
|
| Language |
Greek |
| Subject |
Covalent-organic frameworks |
|
First principles calculations |
|
Hydrogen storage |
|
Metal-organic frameworks |
|
Microporous materials |
|
Modeling and design of novel materials for targeted applications |
|
Multiscale theoretical methods |
|
Physisorption |
|
Αποθήκευση υδρογόνου |
|
Μεταλλο-οργανικά σκελετικά πολυμερή συναρμογής |
|
Μικροπορώδη υλικά |
|
Μοντελοποίηση και σχεδιασμός υλικών για στοχευμένες εφαρμογές |
|
Οργανικά σκελετικά πολυμερή |
|
Συνδυαστικοί υπολογισμοί πολλαπλών θεωρητικών επιπέδων |
|
Υπολογισμοί από πρώτες αρχές |
|
Φυσιορόφηση |
| Issue date |
2009-10-15 |
| Collection
|
School/Department--School of Sciences and Engineering--Department of Chemistry--Doctoral theses
|
|
|
Type of Work--Doctoral theses
|
| Views |
397 |
Μελέτη προσρόφησης υδρογόνου σε νανοδομημένα υλικά
