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On the Chemical Romance Between Gas and Surface, and how to Illuminate it

Pfaff, Sebastian LU (2022) In Lund Reports on Combustion Physics
Abstract
An increasing number of catalysis experiments are conducted at higher pressures to bridge the pressure gap. This means that we need to measure not only the sample surface but also the gas phase around the sample with spatial resolution. This thesis treats the development and applications of two optical techniques that can be used to image the surface of a model catalyst together with the surrounding gas: planar laser-induced fluorescence (PLIF) and 2D-surface optical reflectance (2D-SOR). The strengths and weaknesses of the techniques are discussed. Examples are used to show how the techniques can be applied to study active model catalysts \textit{in situ} under ambient pressure conditions.

PLIF is used to image the CO and CO₂... (More)
An increasing number of catalysis experiments are conducted at higher pressures to bridge the pressure gap. This means that we need to measure not only the sample surface but also the gas phase around the sample with spatial resolution. This thesis treats the development and applications of two optical techniques that can be used to image the surface of a model catalyst together with the surrounding gas: planar laser-induced fluorescence (PLIF) and 2D-surface optical reflectance (2D-SOR). The strengths and weaknesses of the techniques are discussed. Examples are used to show how the techniques can be applied to study active model catalysts \textit{in situ} under ambient pressure conditions.

PLIF is used to image the CO and CO₂ concentrations around various Pd model catalysts during the CO oxidation reaction. 2D-SOR is used to show the surface oxidation process during the same reaction. We show how PLIF and 2D-SOR can be combined with additional techniques, primarily high-energy surface X-ray diffraction (HESXRD), thermography, mass spectrometry (MS) and polarisation modulation infrared reflection absorption spectroscopy (PMIRRAS).

Finally, we show how PLIF and 2D-SOR can be used to bridge the so-called materials gap by taking advantage of the spatial resolution of the techniques to study polycrystalline samples. These samples, which exhibit a plethora of surface structures, can be seen as a step towards more industry-like samples. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Dr. Gregoratti, Luca, Elettra Sincotrone Trieste, Italy.
organization
publishing date
type
Thesis
publication status
published
subject
keywords
planar laser-induced fluorescence, surface optical reflectance, model catalysis, palladium, polycrystal, CO oxidation, heterogeneous catalysis, Fysicumarkivet A:2022:Pfaff
in
Lund Reports on Combustion Physics
issue
244
pages
197 pages
publisher
Department of Combustion Physics, Lund University
defense location
Lecture Hall Rydbergsalen, Department of Physics, Professorsgatan 1, Faculty of Engineering LTH, Lund University, Lund. Zoom: https://lu-se.zoom.us/j/65643466879?pwd=NDF3TlpZeDBsSENzTXlnQ2NHbm5wUT09
defense date
2022-11-25 09:15:00
ISSN
1102-8718
1102-8718
ISBN
978-91-8039-423-9
978-91-8039-424-6
language
English
LU publication?
yes
id
581d0135-5d87-44f6-a0ca-d1da2a22babe
date added to LUP
2022-10-27 18:39:07
date last changed
2023-05-31 09:58:02
@phdthesis{581d0135-5d87-44f6-a0ca-d1da2a22babe,
  abstract     = {{An increasing number of catalysis experiments are conducted at higher pressures to bridge the pressure gap. This means that we need to measure not only the sample surface but also the gas phase around the sample with spatial resolution. This thesis treats the development and applications of two optical techniques that can be used to image the surface of a model catalyst together with the surrounding gas: planar laser-induced fluorescence (PLIF) and 2D-surface optical reflectance (2D-SOR). The strengths and weaknesses of the techniques are discussed. Examples are used to show how the techniques can be applied to study active model catalysts \textit{in situ} under ambient pressure conditions. <br/><br/>PLIF is used to image the CO and CO₂ concentrations around various Pd model catalysts during the CO oxidation reaction. 2D-SOR is used to show the surface oxidation process during the same reaction. We show how PLIF and 2D-SOR can be combined with additional techniques, primarily high-energy surface X-ray diffraction (HESXRD), thermography, mass spectrometry (MS) and polarisation modulation infrared reflection absorption spectroscopy (PMIRRAS).<br/><br/>Finally, we show how PLIF and 2D-SOR can be used to bridge the so-called materials gap by taking advantage of the spatial resolution of the techniques to study polycrystalline samples. These samples, which exhibit a plethora of surface structures, can be seen as a step towards more industry-like samples.}},
  author       = {{Pfaff, Sebastian}},
  isbn         = {{978-91-8039-423-9}},
  issn         = {{1102-8718}},
  keywords     = {{planar laser-induced fluorescence; surface optical reflectance; model catalysis; palladium; polycrystal; CO oxidation; heterogeneous catalysis; Fysicumarkivet A:2022:Pfaff}},
  language     = {{eng}},
  number       = {{244}},
  publisher    = {{Department of Combustion Physics, Lund University}},
  school       = {{Lund University}},
  series       = {{Lund Reports on Combustion Physics}},
  title        = {{On the Chemical Romance Between Gas and Surface, and how to Illuminate it}},
  url          = {{https://lup.lub.lu.se/search/files/126931418/e_spik_ex_Pfaff.pdf}},
  year         = {{2022}},
}