Monte carlo study of hydrogen adsorption by MOF-5 doped with cobalt at ambient temperature and pressure
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Monte carlo study of hydrogen adsorption by MOF‑5 doped with cobalt at ambient temperature and pressure Gustave Assoualaye1 · Ahmat Tom2 · Noël Djongyang1 Received: 23 June 2020 / Accepted: 5 October 2020 © Springer Nature Switzerland AG 2020
Abstract In this work, we are evaluating the hydrogen adsorption capacity at 298 K of cobalt-doped MOF-5 using the Grand Canonical Monte Carlo method. We substitute eight, sixteen, and thirty-two zinc atoms of MOF-5 with cobalt atoms and we obtain Co8-MOF-5, Co16-MOF-5 and CoMOF-5 respectively. For each of these molecules, we determine the pore diameters, the surface, the pore volume, the isosteric heat, and the storage capacities of these doped MOFs. The results show that for Co8-MOF-5 and Co16-MOF-5, doping decreases the pore volume and increases the density. This will lead to an increase in volumetric capacity and a decrease in gravimetric capacity. However, we note a strong adsorbent-adsorbate attraction compared to undoped MOF. This is justified by a high excess capacity for materials with a small surface. Keywords Hydrogen adsorption · MOFs · Doping · Ambient temperature and pressure
1 Introduction Storage remains the only major obstacle to the largescale use of hydrogen in the energy sector today. Indeed, hydrogen is not a source of energy, but a vector, just like electricity. It is used to transport the energy produced by a primary source (petroleum, uranium). It is presented as a possible substitute for hydrocarbons and an efficient way to store renewable energies (wind, solar and hydro), main electricity over a long period. However, its application remains very expensive, because its storage is done by the bias two very energy-consuming methods. Compression under a pressure of 700 bar presents key problems in terms of material, design, and sealing; moreover, reaching the desired pressure requires more than 10% of the stored energy. The cryogenic method, on the other hand, causes large losses of energy during the liquefaction and evaporation processes [1, 2].
However, Metal-Organic Frameworks (MOFs) structures have received very important attention over the past two decades for applications in renewable energy and environmental science [3]. Indeed, the large number of combinations of organic linkers and metal connectors that can be used in principle makes it possible to design materials for a wide variety of potential applications [4–6]. These MOFs have the promise that by modifying building blocks, organic ligands or metallic nodes, i.e. the electronic structure, we can design an optimal material for various applications [7, 8]. Their characteristics, such as high porosity, large surface area, tunable structure, and modifiable functionality, make them very promising to be applied in gas storage and separation [9–12]. This is why the scientific community is placing great emphasis on the study of adsorption of hydrogen by these MOFs at room temperature and pressure to reduce the costs associated with storage. But at room temperature, their storage capacity becomes
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