Room-temperature hydrogen storage performance of metal-organic framework/graphene oxide composites by molecular simulations

Liu, Yuexin, Shen, Dongchen, Tu, Zhengkai, Xing, Lu, Chung, Yongchul G. and Li, Song (2022) Room-temperature hydrogen storage performance of metal-organic framework/graphene oxide composites by molecular simulations. International Journal of Hydrogen Energy. ISSN 0360-3199 (In Press)

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Official URL: https://doi.org/10.1016/j.ijhydene.2022.09.199

Abstract

Metal-organic framework/graphene oxide (MOF/GO) composites have been regarded as potential room-temperature hydrogen storage materials recently. In this work, the influence of MOF structural properties, GO functional group contents and different amounts of doped lithium (Li+) on hydrogen storage performance of different MOF/GO composites were investigated by grand canonical Monte Carlo (GCMC) simulations. It is found that MOF/GO composites based on small-pore MOFs exhibit enhanced hydrogen storage capacity, whereas MOF/GO based on large-pore MOFs show decreased hydrogen storage capacity, which can be ascribed to the novel pores at MOF/GO interface that favors the enhanced hydrogen storage performance due to the increased pore volume/surface area. By integrating the small-pore MOF-1 with GO, the hydrogen storage capacity was enhanced from 9.88 mg/go up to 11.48 mg/g. However, the interfacial pores are smaller compared with those in large-pore MOFs, resulting in significantly reduced pore volume/surface area as well as hydrogen storage capacities of large-pore MOF/GO composite. Moreover, with the increased contents of hydroxyl, epoxy groups as well as carboxyl group modification, the pore volumes and specific surface areas of MOF/GO are decreased, resulting in reduced hydrogen storage performance. Furthermore, the room-temperature hydrogen storage capacities of Li+ doped MOF/GO was improved with increased Li+ at low loading and decrease with the increased Li+ amounts at high loading. This is due to that the introduced Li+ effectively increases the accessible hydrogen adsorption sites at low Li+ loading, which eventually favors the hydrogen adsorption capacity. However, high Li+ loading causes ion aggregation that reduces the accessible hydrogen adsorption sites, leading to decreased hydrogen storage capacities. MOF-5/GO composites with moderate Li+ doping achieved the optimum hydrogen storage capacities of approximately 29 mg/g.

Item Type: Article
Additional Information: Funding information: This work was funded by the Basic Research Foundation of Shenzhen (No. JCYJ20190809101403595).
Uncontrolled Keywords: Hydrogen storage, Composite, Molecular simulation, Pore size, Li+ doping
Subjects: F200 Materials Science
H800 Chemical, Process and Energy Engineering
Department: Faculties > Engineering and Environment > Mechanical and Construction Engineering
Depositing User: John Coen
Date Deposited: 19 Oct 2022 07:30
Last Modified: 19 Oct 2022 08:01
URI: https://nrl.northumbria.ac.uk/id/eprint/50411

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