Ambient mechanochemical solid-state reactions of carbon nanotubes and their reactions via covalent coordinate bond in solution.
Doctor of Philosophy
In its first part, this thesis deals with ambient mechanochemical solid-state reactions of differently functionalized multiple walled carbon nanotubes (MWCNTs) while in its second part it investigates the cross-linking reactions of CNTs in solution via covalent coordinate bonds with transitions metals and carboxylate groups decorating their surfaces. In the first part a series of mechanochemical reactions involving different reactive functionalities on the CNTs such as COOH/OH, COOH/NH2 and COCl/OH were performed. The solid-state unzipping of CNTs leading to graphene formation was confirmed using spectroscopic, thermal and electron microscopy techniques. The non-grapheme products were established using in-situ quadruple mass spectroscopy. The experimental results were confirmed by theoretical simulation calculations using the ‘hot spots’ protocol. The kinetics of the reaction between MWCNT-COOH and MWCNT-OH was monitored using variable temperature Raman spectroscopy. The low activation energy was discussed in terms of hydrogen bond mediated proton transfer mechanism. The second part involves the reaction of MWCNTII COOH with Zn (II) and Cu (II) to form CNT metal-organic frame (MOFs) products that were tested for their effective use as counter-electrodes in dyes sensitized solar cells (DSSC). The thesis concludes by the study of the room temperature reaction between the functionalized graphenes, GOH and G'-COOH followed by the application of compressive loads. The 3D solid graphene pellet product (~0.6gm/cc) is conductive and reflective with a 35MPa ultimate strength as compared to 10MPa strength of graphite electrode (~2.2gm/cc).
CNT Carbon Nanotube; SWCNT Single-Walled Carbon Nanotube; MWCNT Multiple-Walled Carbon Nanotube; DMF N, N-dimethylformamide; MOF Metal organic frameworks; More... CVD Carbon Vapor Deposition; MCR Mechanochemical Reaction; DSSC Dye-Sensitized Solar Cell; SEM Scanning Electron Microscopy; TEM Transmission Electron Microscopy; ATR-IR Attenuated Total reflectance IR spectroscopy; TGA Thermal Gravimetric Analysis; DTA Differential Thermal Analysis; XPS X-ray Photoelectron Spectroscopy; XRD X-Ray Diffraction; DFT Density Function Theory; NEB Nudged Elastic Band; ReaxFF Reactive Force Field Less...