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LUND UNIVERSITY LIBRARIES

C2 Temperature Effects on Carbon Morphology

Pålsson, Alexander LU (2026) FYSK04 20261
Combustion Physics
Department of Physics
Abstract
This thesis investigates the synthesis of advanced carbon materials and clean hydrogen via non-thermal, plasma-assisted pyrolysis of hydrocarbons, offering a sustainable alternative to conventional thermal methods. The study aims to characterize the complex relationship between reactor process parameters, local plasma conditions, and the resulting solid carbon morphology. Experimentally, alternating electric field discharges were utilized to crack hydrocarbon gas. Local gas temperatures were monitored spectroscopically using the Swan band emission of diatomic carbon (C2) as a proxy, while electrical diagnostics and in-line mass spectrometry tracked power input and gas exhaust composition (hydrogen, acetylene, and ethylene). The structural... (More)
This thesis investigates the synthesis of advanced carbon materials and clean hydrogen via non-thermal, plasma-assisted pyrolysis of hydrocarbons, offering a sustainable alternative to conventional thermal methods. The study aims to characterize the complex relationship between reactor process parameters, local plasma conditions, and the resulting solid carbon morphology. Experimentally, alternating electric field discharges were utilized to crack hydrocarbon gas. Local gas temperatures were monitored spectroscopically using the Swan band emission of diatomic carbon (C2) as a proxy, while electrical diagnostics and in-line mass spectrometry tracked power input and gas exhaust composition (hydrogen, acetylene, and ethylene). The structural quality and crystallite size (La) of the synthesized carbon particles were evaluated ex situ using Raman spectroscopy and automated least-squares curve fitting. The results demonstrate that lowering the driving frequency shifts the system toward localized thermal equilibrium, leading to higher C2 rovibrational temperatures. This thermal enhancement accelerates secondary dehydrogenation, yielding higher total hydrogen outputs and a reduced ethylene-to acetylene ratio. Fur- thermore, Raman analysis reveals that these higher local temperatures directly influence carbon morphology, significantly enhancing the yield of highly ordered turbostratic carbon. Finally, tuning the plasma driving frequency provides a critical control parameter for optimizing both material structure and energy yield in advanced material synthesis. (Less)
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author
Pålsson, Alexander LU
supervisor
organization
course
FYSK04 20261
year
type
M2 - Bachelor Degree
subject
keywords
Non-thermal plasma, plasma-assisted pyrolysis, hydrocarbon reforming, plasma reforming, electrical gas discharge, optical emission spectroscopy, OES, Swan bands, Raman spectroscopy, mass spectrometry, turbostratic carbon, carbon morphology, crystallite size, carbon nanomaterials, hydrogen production, methane decomposition, hydrocarbon decomposition
language
English
id
9240040
date added to LUP
2026-06-28 10:57:25
date last changed
2026-06-28 10:57:25
@misc{9240040,
  abstract     = {{This thesis investigates the synthesis of advanced carbon materials and clean hydrogen via non-thermal, plasma-assisted pyrolysis of hydrocarbons, offering a sustainable alternative to conventional thermal methods. The study aims to characterize the complex relationship between reactor process parameters, local plasma conditions, and the resulting solid carbon morphology. Experimentally, alternating electric field discharges were utilized to crack hydrocarbon gas. Local gas temperatures were monitored spectroscopically using the Swan band emission of diatomic carbon (C2) as a proxy, while electrical diagnostics and in-line mass spectrometry tracked power input and gas exhaust composition (hydrogen, acetylene, and ethylene). The structural quality and crystallite size (La) of the synthesized carbon particles were evaluated ex situ using Raman spectroscopy and automated least-squares curve fitting. The results demonstrate that lowering the driving frequency shifts the system toward localized thermal equilibrium, leading to higher C2 rovibrational temperatures. This thermal enhancement accelerates secondary dehydrogenation, yielding higher total hydrogen outputs and a reduced ethylene-to acetylene ratio. Fur- thermore, Raman analysis reveals that these higher local temperatures directly influence carbon morphology, significantly enhancing the yield of highly ordered turbostratic carbon. Finally, tuning the plasma driving frequency provides a critical control parameter for optimizing both material structure and energy yield in advanced material synthesis.}},
  author       = {{Pålsson, Alexander}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{C2 Temperature Effects on Carbon Morphology}},
  year         = {{2026}},
}