Development of Densified Metal-Organic Framework Monoliths for Gas Adsorption and Separation Applications

Metal-organic frameworks (MOFs) have garnered significant interest as promising functional materials with superior gas adsorption and separation performance due to their highly tuneable nature, which enables control over structures and physicochemical properties such as BET area, pore volume, and surface chemistry. However, despite their potential, the practical deployment of these materials in real-world applications has been hindered by their powdery morphology. In recent years, the Adsorption & Advanced Materials Laboratory (AAML) at the University of Cambridge has made significant progress in this regard by developing MOF monoliths (_monoMOFs) that possess high bulk densities and tuneable porosity. These breakthroughs have enabled record-breaking performance in volumetric CH₄ and H₂ storage applications. The fundamental aim of this thesis is to expand the realm of synthesis techniques utilised for the formation of monolithic MOFs, while concurrently exploring the possible applications of the resultant MOF monoliths. Moreover, this thesis endeavours to investigate the association between synthesis processes, properties, and functionalities of MOF monoliths with respect to gas adsorption and separation applications. To achieve this goal, the self-shaping approach for MOF monolith formation was initially applied to a variety of materials, including homochiral CMOM-3S, mesoporous ZIF-90, and Hf-UiO-66 family MOFs. The synthesis protocols employed in this study demonstrate that highly dense MOF monoliths can be produced using large nanoparticles and that MOF gels are not the sole pathway to monolith formation. Rather, slurries and colloidal suspensions have also been shown to be effective in producing dense MOF monoliths. Following a comprehensive study of MOF monolith synthesis, the knowledge acquired was applied to develop efficient monolithic MOFs for targeted applications of interest. Specifically, using a solvent-determined synthesis approach, UTSA-16-Zn, a promising MOF for carbon capture and separation, has been synthesised as dense monoliths for the first time. The synthesis conditions were systematically optimised to attain optimal porosity properties and bulk densities. The resulting UTSA-16-Zn monoliths exhibit outstanding performance in carbon capture and separation applications, demonstrating high volumetric adsorption capacities and selectivity. Additionally, Al-soc-MOF, a benchmark MOF for CH₄ storage and separation, was also investigated. A modulation approach was employed to shape it into monoliths with varying porosity and bulk densities. The impact of modulators on the performance of Al-soc-MOF monoliths was evaluated, revealing exceptional C3/C1 separation and CH₄ storage performance. Overall, this thesis provides invaluable insights into the synthesis, shaping, and application of MOFs monoliths. The findings reported herein shed light on the unique properties and potential of MOF monoliths as a possible solution for tackling pressing environmental challenges.

Name dc:type.qualificationname

Doctor of Philosophy (PhD)

Level dc:type.qualificationlevel

Doctoral

Grantor dc:publisher.institution

University of Cambridge

Year dc:date.issued

2023

Author dc:creator

• Yang, Yue

Advisor dc:contributor.advisor

• Fairen-Jimenez, David

• Adsorption
• MOF monoliths
• MOFs shaping
• Porosity
• Separation

Licence

• https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/9dc2b880-b83b-427b-9dab-90a9b45d45f5/download
• https://www.rioxx.net/licenses/all-rights-reserved/

Language dc:language

eng

DOI dc:identifier.doi

https://doi.org/10.17863/CAM.101618

OAI identifier oai:identifier

oai:www.repository.cam.ac.uk:1810/357356