The doctoral dissertations of the former Helsinki University of Technology (TKK) and Aalto University Schools of Technology (CHEM, ELEC, ENG, SCI) published in electronic format are available in the electronic publications archive of Aalto University - Aaltodoc.
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An Insight: Studies of Atomic and Molecular Adsorption on Co(0001)

Karin Habermehl-Cwirzen

Dissertation for the degree of Doctor of Science in Technology to be presented with due permission of the Department of Engineering Physics and Mathematics for public examination and debate in Auditorium E at Helsinki University of Technology (Espoo, Finland) on the 17th of March, 2006, at 12 o'clock noon.

Overview in PDF format (ISBN 951-22-8088-4)   [812 KB]
Dissertation is also available in print (ISBN 951-22-8087-6)

Abstract

This thesis deals with the adsorption of selected atoms and molecules on a well defined single crystal cobalt surface. X-ray photoelectron spectroscopy has been used to identify different adsorption sites and coverages. Work function measurements have been utilized to monitor the strength of the interaction between adsorbed species and cobalt substrate. Thermal desorption spectroscopy has identified the desorption products and has given information on the activation energies for desorption. By means of low energy electron diffraction measurements the adsorbate unit cell and, by utilizing I-V curve analysis, the atomic positions have been determined.

Adsorption processes are important, e.g. in catalytic reactions, therefore studying adsorption and desorption of atoms and molecules on a well-defined surface can give useful insight information on reactions and how these reactions might be influenced.

We have studied a selection of important atoms and molecules on a Co(0001) surface. Deuterium has been extensively studied as single adsorbate as well as in coadsorption with carbon monoxide and sulfur. Methanol adsorption and O-H bond scission has been an important topic of this thesis. Benzene adsorption has been determined at length, as a single component including I-V curve analysis and DFT calculations, as well as coadsorbed with carbon monoxide. Sulfur, a common unwanted component in a variety of processes like, e.g. crude oil refinery, was investigated as single adsorbate as well as coadsorbed with carbon monoxide.

This thesis consists of an overview and of the following 7 publications:

  1. K. M. E. Habermehl-Cwirzen, K. Kauraala and J. Lahtinen, Hydrogen on cobalt: the effects of carbon monoxide and sulphur additives on the D2/Co(0001) system, Physica Scripta T108 (2004) 28-32. © 2004 The Royal Swedish Academy of Sciences. By permission.
  2. K. Habermehl-Cwirzen, J. Lahtinen and P. Hautojärvi, Methanol on Co(0001): XPS, TDS, WF and LEED results, Surface Science 598 (2005) 128-135. © 2005 Elsevier Science. By permission.
  3. K. M. E. Habermehl-Cwirzen, J. Katainen, J. Lahtinen and P. Hautojärvi, An experimental study on adsorption of benzene on Co(0001), Surface Science 507-510 (2002) 57-61. © 2002 Elsevier Science. By permission.
  4. K. Pussi, M. Lindroos, J. Katainen, K. Habermehl-Cwirzen, J. Lahtinen and A. P. Seitsonen, The (√7̅ × √7̅ )R19.1°-C6H6 adsorption structure on Co(0001): a combined Tensor LEED and DFT study, Surface Science 572 (2004) 1-10. © 2004 Elsevier Science. By permission.
  5. K. Habermehl-Cwirzen, J. Lahtinen and P. Hautojärvi, Coadsorption of CO and C6H6 on Co(0001), Surface Science 584 (2005) 70-76. © 2005 Elsevier Science. By permission.
  6. K. Habermehl-Cwirzen and J. Lahtinen, Sulfur poisoning of the CO adsorption on Co(0001), Surface Science 573 (2004) 183-190. © 2004 Elsevier Science. By permission.
  7. J. Lahtinen, P. Kantola, S. Jaatinen, K. Habermehl-Cwirzen, P. Salo, J. Vuorinen, M. Lindroos, K. Pussi and A. P. Seitsonen, LEED and DFT investigation on the (2 × 2)-S overlayer on Co(0001), Surface Science 599 (2005) 113-121. © 2005 Elsevier Science. By permission.

Keywords: molecular adsorption, atomic adsorption, cobalt, catalysts, surfaces, spectroscopy

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© 2006 Helsinki University of Technology

Last update 2011-05-26