Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.587647
Title: High pressure synthesis and characterisation of layered carbon nitride materials
Author: Lees, V. J.
Awarding Body: University College London (University of London)
Current Institution: University College London (University of London)
Date of Award: 2012
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Abstract:
The research undertaken in this project has involved the synthesis of the carbon nitride material C6N9H3.HCl under high pressures and temperatures in the piston cylinder apparatus. The synthesis conditions of the material have been perfected and the relatively well crystallised products have been characterised in several ways to try to gain a better understanding of the structure of the material. Characterisation techniques used include; elemental analysis, X-ray diffraction, infrared spectroscopy, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, visible, ultraviolet and Fourier Transform Raman spectroscopy. The behaviour of the C6N9H3.HCl material has also been studied further under very high pressures. Diamond anvil cell techniques and synchrotron X-ray radiation have been used to investigate the materials structural behaviour up to pressures in excess of 60 GPa. The decompression of the material has also been investigated. Investigation of the behaviour at high pressures using FTIR was also attempted. The ambient pressure characterisation, high pressure behaviour and decompression of the material have been compared in detail to computational calculations performed on the model structure proposed for the material. Interesting advances in the understanding of the ambient pressure structure and of the high pressure behaviour of the material have been made and the significant structural changes in the material at very high pressures have been explained by the comparison of the experimental and computational results. Due to the highly fluorescent nature of the material under visible Raman lasers it was not possible to obtain Raman spectra of the material in the laboratory at UCL. Therefore the material has been studied using UV and FT Raman techniques using equipment in laboratories in Lyon and Grenoble in France and in Nottingham, UK, in an attempt to obtain vibrational spectra without exciting electronic transitions and to gain more information about the structure.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.587647  DOI: Not available
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