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Lindberg, Vanja
Publications (3 of 3) Show all publications
Lindberg, V. (2007). First principles study of CO reactivity on metallic nano particles. Paper presented at Towards Reality in Nanoscale Materials. Paper presented at Towards Reality in Nanoscale Materials. Levi, Finland
Open this publication in new window or tab >>First principles study of CO reactivity on metallic nano particles
2007 (English)Conference paper, Oral presentation only (Refereed) Published
Alternative title[sv]
Första principen studie av CO-reaktivitet på metalliska nanopartiklar
Abstract [en]

The activity of a surface is determined by the local electronic structure. When nano particles are adsorbed, the catalytic properties will change. Surfaces with adsorbed nano particles often show a significantly higher chemical reactivity than the clean counterpart. Gold, for instance, shows an extra high activity towards many reactions, such as low-temperature catalytic combustion, partial oxidation of hydrocarbons and CO oxidation when dispersed as ultra-fine particles on metal oxide surfaces. In the case of CO oxidation, the activity has been observed to depend critically on the nano particle size, the nature of the support and the detailed synthetic procedure. Since it has been observed experimentally that the chemical reactivity of a nanoparticulated surface tend to depend on the size of the adatom structures, suggesting a quantum size effect, we find it well motivated to perform a theoretical investigation with focus on the cluster-size dependence. We have chosen to model CO interaction with sodium nano particles with focus on small particles, containing only a few atoms, since we expect the eventual quantum effects to be most pronounced for these. Further, we limit our investigation to unsupported nano particles because our previous investigations [1] have shown that it is predominately states localized to the nano particle region that contribute to the local electronic structure above the particle itself. The calculations have been performed in the context of density functional theory applying the MIKA real-space program package [2], using norm-conserving pseudo-potentials for the molecule. The nano particle has been modeled as a cylindrically symmetric quantum dot. For further details, see [3,4]. Our results show that the charge transfer between the nano particle and the CO molecule depends critically on the nano particle size, and that this dependence is intimately connected to the local electronic structure at the point where the molecule approaches the particle. The key factor for charge transfer turns out to be the presence of states with the symmetry of the chemically active molecular orbital at the Fermi level. [1] T. Torsti, V. Lindberg, M. J. Puska ,and B. Hellsing, Phys. Rev. B 66, 235420 (2002). [2] M. Heiskanen, T. Torsti, M. J. Puska, and R. M. Nieminen, Phys. Rev. B 63, 245106 (2001). [3] V. Lindberg and B. Hellsing, J. Phys. Condens. Matter 17, S1075 (2005). [4] V. Lindberg, T. Petersson, and B. Hellsing, Surf. Sci. 600, 6 (2006).

Abstract [sv]

En ytas aktivitet bestäms av den lokala elektronstrukturen. När nanopartiklar adsorberas på en metallyta, ändras den lokala elektronstrukturen och därmed också de kemiska egenskaperna. Man har sett att den kemiska reaktiviteten ofta blir större för ytor med adsorberade nanopartiklar, än vad den är för rena ytor. Här studeras hur den kemiska reaktiviteten beror på storleken av de adsorberade nanopartiklarna. Idetta fall CO reaktivitet på en Na-yta. Vi visar att det finns ett tydligt storleksberoende, som kan hänvisas tillbaka på kvantmekaniska effekter.l

Place, publisher, year, edition, pages
Levi, Finland: , 2007
Keywords
nano particle, reaktivity, cathalysis, quantum mechanics, quantum dots
National Category
Mathematics Applied Mechanics
Identifiers
urn:nbn:se:bth-8353 (URN)oai:bth.se:forskinfoA966F08FDE0498F0C125750100566B22 (Local ID)oai:bth.se:forskinfoA966F08FDE0498F0C125750100566B22 (Archive number)oai:bth.se:forskinfoA966F08FDE0498F0C125750100566B22 (OAI)
Conference
Towards Reality in Nanoscale Materials
Note
http://www.fyslab.hut.fi/~tjh/workshop07.html#programmeAvailable from: 2012-09-18 Created: 2008-11-14 Last updated: 2015-06-30Bibliographically approved
Adams, R. & Lindberg, V. (2007). What is the word for engineering in Swedish: students conception of their discipline.
Open this publication in new window or tab >>What is the word for engineering in Swedish: students conception of their discipline
2007 (English)Other (Other academic)
Abstract [en]

Engineering education in Sweden as in the rest of the world is experiencing a decline in student interest. There are concerns about the ways in which students think about engineering education, why they join an academic programme in engineering, and why they persist in their studies. In this context the aims of the Nationellt ämnesdidaktiskt Centrum för Teknikutbildning i Studenternas Sammanhang project (CeTUSS) is to investigate the student experience and to identify and support a continuing network of interested researchers, as well as in building capacity for disciplinary pedagogic investigation. The Stepping Stones project brings together these interests in a multi-researcher, multi-institutional study that investigates how students and academic staff perceive engineering in Sweden and in Swedish education. The first results of that project are reported here. As this study is situated uniquely in Swedish education, it allows for exploration of a Swedish perspective on conceptions of engineering. The Stepping Stones project was based on a model of research capacity-building previously instantiated in the USA and Australia (Fincher & Tenenberg, 2006).

Keywords
students conception of their discipline, engineering
National Category
Mathematics Pedagogy
Identifiers
urn:nbn:se:bth-8978 (URN)oai:bth.se:forskinfoF8C7A429678C07B0C125733E004EBE59 (Local ID)oai:bth.se:forskinfoF8C7A429678C07B0C125733E004EBE59 (Archive number)oai:bth.se:forskinfoF8C7A429678C07B0C125733E004EBE59 (OAI)
Note
http://www.it.uu.se/research/publications/reports/2007-018/Available from: 2012-09-18 Created: 2007-08-21 Last updated: 2015-06-30Bibliographically approved
Torsti, T. & Lindberg, V. (2006). Real-space electronbic-property calculations for nano-scale structure. In: (Ed.), Handbook of Theoretical and Computational Nanotechnology, edited by Michael Rieth and Wolfram Schommers: (pp. 771-795). American Scientific Publishers
Open this publication in new window or tab >>Real-space electronbic-property calculations for nano-scale structure
2006 (English)In: Handbook of Theoretical and Computational Nanotechnology, edited by Michael Rieth and Wolfram Schommers, American Scientific Publishers , 2006, p. 771-795Chapter in book (Other academic)
Place, publisher, year, edition, pages
American Scientific Publishers, 2006
Keywords
nanotechnology
National Category
Mathematics Telecommunications
Identifiers
urn:nbn:se:bth-8979 (URN)oai:bth.se:forskinfoCF58B1DF9AC67BC5C125733E004E7EE2 (Local ID)1-58883-042-X (ISBN)oai:bth.se:forskinfoCF58B1DF9AC67BC5C125733E004E7EE2 (Archive number)oai:bth.se:forskinfoCF58B1DF9AC67BC5C125733E004E7EE2 (OAI)
Available from: 2012-09-18 Created: 2007-08-21 Last updated: 2015-06-30Bibliographically approved

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