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Title: Studies of the chemistry of carbon nanotubes
Author: Luksirikul, Patraporn
Awarding Body: Oxford University
Current Institution: University of Oxford
Date of Award: 2011
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Abstract:
The work described in this thesis is concerned with the development of fullerenes and single-walled carbon nanotubes (SWNTs) derivatives by novel chemistries for two main objectives: (i) use of fullerenes derivatives and single-walled carbon nanotubes (SWNTs) as a platform for drug delivery; (ii) use of functionalised SWNTs in nanoparticles catalysts for low temperature fuel cells applications. Chapter 1 gives an overview of structure, synthesis, properties and potential applications of carbon nanotubes, Also, reviews on functionalisation and filling of carbon nanotubes are presented. The latter part of this chapter summarises the most update studies of carbon nanotubes as supports for fuel cells applications. Chapter 2 demonstrates the synthetic methods for chemical functionalized fullerenes (Pf-C6o) which are employed as reversible nano-corks for single-walled carbon nanotubes (SWNTs). In this proof-of-the-principle study, SWNTs are filled with copper acetate or uranyl acetate materials. These encapsulated materials are then blocked by pf-C6o to avoid their leaching from the SWNTs. The use of pf-C6o as corks allows the cleanup of the acetates deposited exterior of the SWNTs without leaching the filled material. The concept of a pH-triggered cascade release of encapsulated materials in SWNTs is also demonstrated. Chapter 3 presents the chemical functionalisations of sidewalls of single-walled carbon nanotubes via diaryldiazomethanes: bis( 4( dimethylamino )phenyl)diazomethane, bis( 4- methoxypheny I )diazomethane, ( 4-(hydroxymethy I )pheny I ) (pheny l)diazomethane and bis( 4-iodophenyl)diazomethane, etc. Covalent functionalisation of SWNTs is carried out using thermolysis of diaryldiazomethane compounds to generate reactive carbene as an intermediate which can then directly couple to benzoidal ring of the tubular graphitic walls. The resulting functionalised products are characterised by TGA, FTIR, and Raman, HRTEM and STEM techniques. The chemical functionalisations are shown to enhance dispersibility of the SWNTs in THF. Their immobilization with gold colloid with high electron diffraction is then conducted in order to increase the contrast during the TEM imaging of the composite material. The gold colloids were covalent attached to the sidewalls of carboxylated SWNTs via cysteine coupling. The covalent tagging of f-SWNT carboxylates are also confirmed by a high-resolution AFM. Chapter 4 describes synthesis, characterisation and testing of chemical functionalized SWNTs as support materials for fuel cells applications. First, various chemical functional groups are immobilized on the sidewalls of SWNTs which are subsequently used as nuclei to allow the growth of palladium nanoparticles thereupon. In this study, formic acid adsorption strengths in term of chemical shifts on these supported palladium nanoparticles on SWNTs are for the first time evaluated by 13C-NMR solution spectroscopy. It is shown that the higher chemical shift (higher adsorption strength) gives higher activity for the formic electro-oxidation which depends on the electronic donating ability of a particular functional group when the size, shape, loading of palladium nanoparticles are well controlled.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.558450  DOI: Not available
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