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O: Fachverband Oberflächenphysik

O 68: Surface dynamics: Reactions, elementary processes and phase transitions I

O 68.5: Vortrag

Mittwoch, 14. März 2018, 16:00–16:15, MA 043

Water formation reaction physically confined below silica thin films: real time observation using LEEM and PEEM — •Mauricio Prieto¹, Hagen Klemm¹, Feng Xiong², Daniel Gottlob¹, Dietrich Menzel¹, Thomas Schmidt¹, and Hans-Joachim Freund¹ — ¹Department of Chemical Physics, Fritz Haber Institute of the Max Planck Society. Berlin - Germany — ²Department of Chemical Physics, University of Science and Technology of China, Hefei - P. R. China.

Thin oxide films are interesting models for the studying fundamental properties of real catalysts [1]. Among the more studied oxides, silica has caught the attention due to its relevance in the field of heterogeneous catalysis as a support or active component [2]. In addition, silica thin films supported on Ru(0001) have shown the ability of intercalating molecules into the confined space existing between the crystal surface and the oxide film [3]. We will show results regarding the study of the hydrogen oxidation with the aberration corrected spectro-microscope SMART [4] at the synchrotron light source BESSY-II in Berlin, by means of local XPS, LEED and LEEM. For instance, the reaction occurs as a front characterized by a sudden change in intensity in LEEM. The apparent activation energy of the process could be evaluated and compared with data obtained for bare Ru(0001), thus addressing the effect of confinement on the chemical reaction.

[1] Libuda, et al., Microchim. Acta 156, 9 (2006) [2] Ulrich, et al., Phys. Rev. Lett. 102, 016102 (2009) [3] Emmez, et al.; J. Phys. Chem. C 118, 29034 (2014) [4] Schmidt, et al., Ultram. 110 1358 (2010)