Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 69: Nanostructures at Surfaces: Dots, Particles, Clusters
O 69.6: Poster
Mittwoch, 9. März 2016, 18:15–20:30, Poster A
Monitoring the interaction of CO with graphene supported metal nanoparticles by vibrational spectroscopy — •Heshmat Noei1, Marcus Creutzburg1,2, Dirk Franz1,2, and Andreas Stierle1,2 — 1Deutsches Elektronen Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany — 2Department of Physic, University Hamburg, D-20355 Hamburg, Germany
Small metal nanoparticles dispersed on porous substrates have gained interest in surface science because of their widespread applications, especially in heterogeneous catalysis. It was shown that nanoparticles form ordered arrays on graphene substrates using the moiré of graphene/Ir(111) as a template. The size of these nanoparticles can be carefully controlled on graphene/Ir(111) by the amount of deposited material. Here we report the first describing vibrational spectroscopic studies on Ir, Pt, Rh and Au metal-covered graphene/Ir(111) substrate using CO as probe and/or reactant to monitor the frequency of C-O binding to the metal nanoparticles. The UHV-IRRAS apparatus allowed us to record high-quality IR data and turned out to be a powerful tool to investigate well-arranged metal/grapehne/Ir(111) system. It is found that CO bound on two sites on metal clusters: (1) on-top terraces atoms at low CO coverage and (2) on top-edge atoms at higher CO coverage. The adsorption energy, thermal stability and shape of metal clusters on graphene/Ir(111) are further investigated with respect to the position and intensity of the C-O stretching bands.