Yang, Yuchen;
(2020)
2D/3D composites of porous graphene carbons, MOFs and coordinated polymers for CO2 capture and separation.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
Global warming caused by greenhouse gases (GHGs) emission has become one of the most challenging issue faced by humankind, with its growing impact on the environment and human health. Anthropogenic carbon dioxide (CO2), as the major greenhouse gas, is steadily escalating and poses the most challenging environmental concerns of our age. To mitigate CO2 effectively and economically, researches have been conducted to improve CO2 capture and separation technologies through design and development of advanced functional materials. Such materials should satisfy long time stability, selectively capture CO2 at varies concentration from industrial flue gas. Such capture materials should also come in low cost and be able to produce in large scale. In order to achieve such criteria, the materials are crucial. For this, many types of sorbents have been identified. For example, carbons, MOFs and coordinated polymers showed promising CO2 adsorption and separation properties. Membrane sieving is also proposed as an energy efficient route specially for CO2 separation. By keeping above requirements in mind, this thesis work was aimed at design and development of efficient CO2 capture and separation structures. In particular, I aimed at materials that can offer tuneable porosities and also able to scale up. Accordingly, the graphene oxide, MOFs and polymers could justify the needs due to their flexibility and chemical stability. Thus, this thesis work was exclusively focused on tailoring these three types of materials, which were introduced in detailed manner in the three chapters. Firstly, in order to develop the graphene oxide-based sorbent, I specifically concentrated on achieving the highest porosity graphene networks by studying various types of 2D graphite precursors. For this, the graphite precursors were subjected to oxidation (graphene-oxide) followed by thermal reduction. The characterizations revealed direct precursor depended porosity development in the products. With these porosities in mind the work was further extended to produce the functionalised solids for CO2 capture, an application of material for post-combustion flue-gas carbon capture. Next, such extensive porosity graphene structure further utilized in producing graphene/MOF based composite sorbents. MOF nanocrystals were in-situ grown onto graphene porous networks to develop optimal porosity characteristics. Such structures fully monitored by complementary techniques such as diffraction, spectroscopy, imaging and porosity. The CO2 capture capacity and selectivity from N2 were studied at different experimental conditions. The structure related CO2 capture performance was analysed and discussed. Finally, as a complementary for the porous sorbents, the membrane sieving separation studies were carried out using polymers of intrinsic micrporosity (PIM). Here, PIM was used as a backbone and exploited the structure porosity, by introducing MOF nanocrystals and graphene networks. By changing the concentration of components, the membrane properties, such as thickness, flexibility, stability and specifically porosity, were optimized. These membranes were examined for CO2 selectivity towards N2 and H2. Within the scope of this work, a business plan was then developed based on the thoroughly understanding of the materials design, development and CO2 capture properties.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | 2D/3D composites of porous graphene carbons, MOFs and coordinated polymers for CO2 capture and separation |
| Event: | UCL (University College London) |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2020. Original content in this thesis is licensed under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) Licence (https://creativecommons.org/licenses/by/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10107748 |
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