Emmanouel Klontzas

Improving Hydrogen Storage Capacity of MOF by Functionalization of the Organic Linker with Lithium Atoms

A combination of quantum and classical calculations have been performed in order to investigate hydrogen storage in metal-organic frameworks (MOFs) modified by lithium alkoxide groups. Ab initio calculations showed that the interaction energies between the hydrogen molecules and this functional group are up to three times larger compared with unmodified MOF. This trend was verified by grand canonical Monte Carlo (GCMC) simulations in various thermodynamic conditions. The gravimetric capacity of the Li-modified MOFs reached the value of 10 wt % at 77 K and 100 bar, while our results are very promising at room temperature, too, with 4.5 wt %.

Designing 3D COFs with Enhanced Hydrogen Storage Capacity

Hydrogen storage properties have been studied on newly designed three-dimensional covalent-organic framework (3D-COF). The design of these materials was based on the ctn network of the ultralow density COF-102. The structures were optimized by multiscale techniques and the optimized structures were checked for their storage capacities by grand canonical Monte Carlo simulations. Our simulations demonstrate that the gravimetric uptake of one of these new COFs can overpass the value of 25 wt % in 77 K and reach the Department of Energys target of 6 wt % in room temperature, classifying them between the top hydrogen storage materials.

Enhancement of hydrogen adsorption in metal-organic frameworks by the incorporation of the sulfonate group and Li cations. A multiscale computational study.

By means of ab initio methods, the effect on the H(2) storage ability of a newly proposed organic linker for IRMOF-14 has been studied. The linker comprises a negatively charged sulfonate (-SO(3)(-1)) group in combination with a Li cation. It is found that these two charged groups significantly increase the interaction energy between the hydrogen molecules and the new proposed organic linker of the MOF. The substituted group of the linker may host up to six hydrogen molecules with an average interaction energy of 1.5 kcal/mol per H(2) molecule. This value is three times larger than the binding energy over the bare linker that has been obtained from DFT calculations. GCMC atomistic simulations verified that the proposed material can be qualified among the highest adsorbing materials for volumetric capture of H(2), especially at ambient conditions. This functionalization strategy can be applied in many different MOF structures to enhance their storage abilities.

The effect of structural and energetic parameters of MOFs and COFs towards the improvement of their hydrogen storage properties

Open-framework materials have been proposed as potential materials for hydrogen storage. Metal-organic framework (MOF) and covalent-organic framework (COF) materials are under extensive study to discover their storage abilities. In particular the IRMOF family of materials have been considered as ideal to study the effect of different factors that affect the hydrogen storage capacity. In this paper, we analyse the effect of different factors such as surface area, pore volume and the interaction of hydrogen with the molecular framework on the hydrogen uptake of such materials. Through this analysis we propose guidelines to enhance hydrogen storage capacity of already synthesized materials and recommend advanced materials for this application.

First Principles Theoretical Study of the Interaction of Hydrogen with the Ultra‐Microporous Materials IRMOF And COF

An important problem, that has to be solved before hydrogen shall become a fuel for commercial applications, is the choice of a suitable storage media. It has been proposed that the incorporation of porous materials in a gas tank could lead to an increase of the gas amount stored in the tank with safety. Recently, new families of porous materials, such as Metal‐Organic Frameworks (MOF) and Covalent‐Organic Frameworks (COF) has been proposed for hydrogen storage application due to their ability to absorb large amounts of hydrogen.Materials that can be suitable for hydrogen storage should meet some requirements, such as high surface area, high pore volume, chemical and thermal stability and increased energetic interactions with the hydrogen. Many MOF and some COF materials have achieved to capture big amounts of hydrogen in their structures, which has been attributed to the some of the above mentioned properties. The investigation of the interaction of hydrogen with the host materials is a crucial step for ...