Hybrid nanocarbon aerogels for CO2 capture
File(s)
Author(s)
Costantini, Tommaso
Type
Thesis
Abstract
The urgent need to address climate change is motivating the development of efficient CO2 scrubbers for use both at the point of emission and for more general direct air capture. Single walled carbon nanotubes (SWCNTs) have attracted great interest over the last three decades for their chemical, physical and mechanical properties. SWCNT assemblies are promising supporting frameworks for CO2 sorbents, offering high surface area and a variety of surface functionalisations to accommodate active capture materials. However, assembling SWCNT high quality networks remains challenging due to the complexity of dissolving individual SWCNTs and binding them to assemble strongly interconnected networks with defined architectures.
Since current SWCNT syntheses generally produce polydispersed, entangled networks, one of the main efforts of the field involves the development of efficient wet processing protocols to dissolve, sort and functionalise SWCNTs for specific applications. This thesis develops a one-pot protocol using reductive chemistry to prepare true SWCNT solutions and covalent cross-link them to produce robust organogels. The reaction conditions were explored systematically to determine the conditions that maximise the cross-linking yield. The reactivity was found to depend strongly on both charge stoichiometry (number of additional electrons per carbon) and linker stoichiometry (number of bifunctional molecules per additional electron). Removal of the solvent from the organogels by supercritical or freeze drying produced dry aerogel and cryogel networks, preserving the intrinsic morphology of the network or introducing hierarchical porosity respectively. In addition, combining different carbonaceous precursors provides a strategy to create further hierarchy in the structure...
Since current SWCNT syntheses generally produce polydispersed, entangled networks, one of the main efforts of the field involves the development of efficient wet processing protocols to dissolve, sort and functionalise SWCNTs for specific applications. This thesis develops a one-pot protocol using reductive chemistry to prepare true SWCNT solutions and covalent cross-link them to produce robust organogels. The reaction conditions were explored systematically to determine the conditions that maximise the cross-linking yield. The reactivity was found to depend strongly on both charge stoichiometry (number of additional electrons per carbon) and linker stoichiometry (number of bifunctional molecules per additional electron). Removal of the solvent from the organogels by supercritical or freeze drying produced dry aerogel and cryogel networks, preserving the intrinsic morphology of the network or introducing hierarchical porosity respectively. In addition, combining different carbonaceous precursors provides a strategy to create further hierarchy in the structure...
Version
Open Access
Date Issued
2023-04-16
Date Awarded
2024-02-01
Copyright Statement
Creative Commons Attribution NonCommercial NoDerivatives Licence
Advisor
Shaffer, Milo
Sponsor
Bio Nano Consulting (Firm)
Engineering and Physical Sciences Research Council
Grant Number
EP/R512540/1
Publisher Department
Materials
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)