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

Sebastian Pfaff

Research output: ThesisDoctoral Thesis (compilation)

227 Downloads (Pure)


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.
Original languageEnglish
Awarding Institution
  • Faculty of Engineering, LTH
  • Zetterberg, Johan, Supervisor
  • Lundgren, Edvin, Assistant supervisor
Award date2022 Nov 25
Place of PublicationLund
ISBN (Print)978-91-8039-424-6
ISBN (electronic) 978-91-8039-423-9
Publication statusPublished - 2022

Bibliographical note

Defence details
Date: 2022-11-25
Time: 09:15
Place: 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
Webinar ID: 656 4346 6879 Passcode: 330653
External reviewer(s)
Name: Gregoratti, Luca
Title: Dr.
Affiliation: Elettra Sincotrone Trieste, Italy.

Subject classification (UKÄ)

  • Atom and Molecular Physics and Optics

Free keywords

  • planar laser-induced fluorescence
  • surface optical reflectance
  • model catalysis
  • palladium
  • polycrystal
  • CO oxidation
  • heterogeneous catalysis
  • Fysicumarkivet A:2022:Pfaff


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