Dresden 2017 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 89: Oxide and Insulator Surfaces: Adsorption III
O 89.5: Vortrag
Donnerstag, 23. März 2017, 11:30–11:45, TRE Phy
Adsorption properties and reactivity of single Rh atoms on Fe3O4 (001) — •Jan Hulva1, Roland Bliem1, Zdeněk Jakum1, Adam Závodný1, Michael Schmid1, Ulrike Diebold1, Peter Blaha2, and Gareth S. Parkinson1 — 1Institute of Applied Physics, TU Wien, Wiedner Hauptstrasse 8-10, 1040 Vienna, Austria — 2Institute of Materials Chemistry, TU Wien, Getreidemarkt 9, 1060, Vienna, Austria
Single atom catalysis operates in the smallest particle size limit of supported metal catalyst. Although It has been shown that this approach is promising for the synthesis of highly active catalysts containing only small amount of expensive metal [1], the concept still remains controversial. It has been shown that Fe3O4 (001) surface is able to stabilize single metal atoms up to relatively high temperatures [2] due to its surface reconstruction [3]. This makes it an ideal candidate for a model system for fundamental studies of the single atom catalysis.
STM shows that Rh adatoms can be adsorbed at the magnetite surface in several different configurations. This can be linked to different chemical states of Rh seen by XPS. As predicted by DFT, CO bounds strongly to Rh adatoms and dimers giving an origin to two desorption peeks in TPD at 460K and 530K. Strong interaction of CO and Rh also leads to CO2 formation by Mars-van Krevelen mechanism at these temperatures.
[1] Qiao B., Nature Chemistry, 3, (2011): 634-641. [2] Novotný Z., et al., Phys.Rev.Lett.108(2012): 216103 [3] Bliem R., et al. Science 346 (2014): 1215-1218.