Regensburg 2016 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 73: Surface Dynamics: Reactions and Elementary Processes
O 73.5: Poster
Mittwoch, 9. März 2016, 18:15–20:30, Poster A
Controlling Alkyne Catalysis on an Atom-By-Atom Basis — Marian D. Rötzer, Andrew S. Crampton, •Maximilian Krause, Florian F. Schweinberger, and Ueli Heiz — Technische Universität München, Dept. of Chem. and Catalysis Research Center, Chair of Physical Chemistry, Lichtenbergstr. 4, 85748 Garching, Germany
Alkanes, alkenes and alkynes are major feedstocks for the chemical industry and their reactions on supported metal nanoparticles are applied in a variety of processes for the synthesis of important chemicals. To be able to develop new and efficient catalysts for those reactions a deep fundamental understanding with respect to adsorption, mechanistic details, poisoning, etc. has to be gained. Size-selected clusters supported on thin films under UHV conditions meet the requirements of a defined model system for unraveling underlying catalytic principles. To this end, we investigated the surface chemistry of 3-hexyne on size-selected Ptn clusters on MgO(100)/Mo(100). This model system is characterized by TPR and IRRAS and compared to the Pt(111) surface. Depending on the cluster size, different reaction pathways are favored or even completely blocked. The selectivities towards such pathways are size-dependent, though not linearly. IRRAS experiments showed re-emerging free surface sites when the reaction products are desorbed, though a characteristic red-shift of the CO-stretch signal points to the remainder of carbonaceous species, as supported by AES.
This work has been supported by the Clariant Produkte (Deutschland) GmbH in the framework of the Munich Catalysis (MuniCat) program, a strategic alliance between TUM and Clariant.