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O: Fachverband Oberflächenphysik
O 83: Surface Chemistry and Growth
O 83.4: Vortrag
Donnerstag, 19. März 2015, 11:15–11:30, MA 144
Effect of metal substrates on immobilised catalyst performance — •David A. Duncan1, Peter S. Deimel1, Anthoula Weingarten1, Runyuan Han1, Kevin C. Prince2, Robert G. Acres2, Albano Cossaro2, Alberto Verdini2, Luca Floreano2, Wilhelm Auwärter1, Peter Feulner1, Anthoula C. Papageorgiou1, Francesco Allegreti1, and Johannes V. Barth1 — 1TU München, Germany — 2Elettra, Trieste, Italy
A key motivation for surface science is to merge the selectivity of homogenous catalysts with the ease of recovery in heterogenous catalysis. Recent studies1 in this field have focussed on immobilising metal-organic species at solid surfaces for improved control of catalytic conversions. However, with metal supports the reactivity of surface-anchored species has been lacklustre, frequently requiring either low temperatures or large exposures for axial ligation at complexed metal centres2 suggesting that the interaction with the substrate has a notable effect. We have studied, in UHV, the reactivity of ruthenium tetraphenyl porphyrin (Ru-TPP) and its Ti analogue towards molecular oxygen when confined to the Ag(111) surface. For surface-confined Ru-TPP, after a dosage of 20,000 L, no oxo-ruthenium species evolved, whereas exposing Ti-TPP to ∼100 L induces nearly complete oxidiation. This might suggest a shift in the so called “Volcano plot” of the Sabatier Principle towards metal complexes that are traditionally thought of as being too reactive for certain catalytic reactions.
1) B. Hulsken et al Nat Nano, 2007, 2 285; 2) BE Murphy et al. ACS Nano, 2014, 8, 5190; K Seufert et al., Nat Chem, 2011, 3, 114