Berlin 2015 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 24: Catalysis: Structural Effects
O 24.2: Vortrag
Dienstag, 17. März 2015, 10:45–11:00, MA 144
Alumina model supports on NiAl(110) studied by High-Pressure STM — •Rik Mom1, Joost Frenken2, and Irene Groot1 — 1Huygens-Kamerlingh Onnes Laboratory, Leiden, The Netherlands — 2ARCNL, Amsterdam, The Netherlands
Modern research on the atomic- and molecular-scale working mechanisms of industrial catalysis increasingly involves efforts to extend the use of traditional surface science characterization tools to high pressures and to increase the complexity of the investigated model catalysts.
In order to mimic the alumina that is often used to support catalytic nanoparticles, ultrathin alumina films have been developed on single crystal metal surfaces. Because of its high degree of crystallinity and good conductivity, the Al2O3/NiAl(110) system has received particular interest[1].
Here, we investigate the stability of this thin-film support under high pressures, e.g. 1 bar, of various gasses. We used high-pressure STM[2] to follow the structural evolution of the film and post-mortem XPS to inspect the end result. Our observations show that alumina films on NiAl(110) are stable under 1 bar of H2, O2 and H2S. Under millibar levels of H2O, film growth occurs in defective areas, gradually expanding these over the surface. Experiments using thicker alumina films with the same level of crystallinity show that film thickness has little effect on the reactivity towards water. [1] G.H. Simon et al., J. Phys.: Condens. Matter 24, 084007 (2012) [2] C.T. Herbschleb et al., Rev. Sci.Instr. 85, 083703 (2014)