Development and Application of Gas-phase Raman Spectroscopy Techniques for Analysis of Carbon Nanotube Synthesis Processes
type: CreativeWork
description: Carbon Nanotubes (CNTs) are structures with outstanding chemical and physical properties, making them an attractive candidate for multiple industrial applications. They can be produced via different techniques, with the floating catalyst chemical vapour deposition (FC-CVD) being one of the most attractive solutions for the mass production of CNTs. The current production rate of high-quality CNT material with tailored properties falls short of the rising industrial demand. One of the major limiting factors for high volume production is insufficient knowledge of underlying chemical processes that result in the CNTs growth via FC-CVD, making the rate-limiting factors of the system unknown. Another limiting factor in the manufacture of high quality CNTs is the lack of on-the-fly monitoring of synthesis parameters. In this study, two Raman-based spectroscopic techniques were tested for the realisation of in situ measurements in a FC-CVD reactor. Cavity-enhanced Raman spectroscopy (CERS) was found to be a powerful low-cost high-resolution tool for analysis of non-reacting gaseous mixtures. Based on experimental results, its application for analysis of reacting flows was deemed to be limited due to localised changes in refractive index in reacting flows. A comprehensive model was derived, which was able to calculate an expected amplification of Raman signal, compared to a more typical free space spontaneous Raman scattering setup. Quality of the model was confirmed by experimental measurements. Pulsed Laser Raman spectroscopy setup was designed, constructed and implemented to perform in situ measurements of the CNT synthesis process via FC-CVD. A bespoke cross-shaped reactor with a purging system was developed and applied to provide continuous optical access to the reaction volume of FC-CVD reactor. Created Fluent-based computational fluid dynamics model was used to analyse fluid flow pattern and molar fraction distribution of chemicals inside the reactor in order to devel…
abstract: Carbon Nanotubes (CNTs) are structures with outstanding chemical and physical properties, making them an attractive candidate for multiple industrial applications. They can be produced via different techniques, with the floating catalyst chemical vapour deposition (FC-CVD) being one of the most attractive solutions for the mass production of CNTs. The current production rate of high-quality CNT material with tailored properties falls short of the rising industrial demand. One of the major limiting factors for high volume production is insufficient knowledge of underlying chemical processes that result in the CNTs growth via FC-CVD, making the rate-limiting factors of the system unknown. Another limiting factor in the manufacture of high quality CNTs is the lack of on-the-fly monitoring of synthesis parameters. In this study, two Raman-based spectroscopic techniques were tested for the realisation of in situ measurements in a FC-CVD reactor. Cavity-enhanced Raman spectroscopy (CERS) was found to be a powerful low-cost high-resolution tool for analysis of non-reacting gaseous mixtures. Based on experimental results, its application for analysis of reacting flows was deemed to be limited due to localised changes in refractive index in reacting flows. A comprehensive model was derived, which was able to calculate an expected amplification of Raman signal, compared to a more typical free space spontaneous Raman scattering setup. Quality of the model was confirmed by experimental measurements. Pulsed Laser Raman spectroscopy setup was designed, constructed and implemented to perform in situ measurements of the CNT synthesis process via FC-CVD. A bespoke cross-shaped reactor with a purging system was developed and applied to provide continuous optical access to the reaction volume of FC-CVD reactor. Created Fluent-based computational fluid dynamics model was used to analyse fluid flow pattern and molar fraction distribution of chemicals inside the reactor in order to devel…
author: Kuvshinov, Maxim
language: eng
keywords: Carbon nanotubes, FC-CVD, Floating Catalyst, Chemical Vapour Deposition, Spontaneous Raman, Spectroscopy, Gas-phase
license: https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/03755d0f-f738-4a27-84fc-c5e40840f360/download
license: https://www.rioxx.net/licenses/all-rights-reserved/
date published: 2021-03-01
date modified: 2026-07-22T22:24:25Z
provider: Cambridge University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Cambridge

PropertyValue
property ID: DOI
value: 10.17863/CAM.73878