Dresden 2014 – scientific programme
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O: Fachverband Oberflächenphysik
O 49: Surface Chemical Reactions and Heterogeneous Catalysis III
O 49.9: Talk
Wednesday, April 2, 2014, 12:30–12:45, PHY C 213
Surface reaction steps of dicyclohexylmethane/diphenylmethane on Pt(111) — •Christoph Gleichweit1, Oliver Höfert1, Nicole Brückner2, Peter Wasserscheid2, Hans-Peter Steinrück1, and Christian Papp1 — 1University Erlangen-Nuremberg, Chair of Physical Chemistry II, Egerlandstr. 3, 91058 Erlangen, Germany — 2University Erlangen-Nuremberg, Institute of Chemical Reaction Engineering, Egerlandstr. 3, 91058 Erlangen, Germany
The liquid organic hydrogen carrier pair dicyclohexylmethane (DHM) and diphenylmethane (DPM) was studied on Pt(111) by high-resolution X-ray photoelectron spectroscopy and temperature programmed desorption (TPD) in order to elucidate the reaction steps. Using physical vapor deposition, the molecule was first adsorbed under ultra high vacuum conditions, and subsequently the surface reaction was monitored during heating. The signals of the individual surface species during the reaction of the loaded carrier (DHM) are compared to the ones of the unloaded carrier (DPM), giving information on the dehydrogenation mechanism. During adsorption, the development of monolayer and multilayer signals is observed clearly in the C 1s region for both DHM and DPM. When heating the sample continuously, the multilayer of DHM desorbs at about 230 K. Subsequently, the dehydrogenation of DHM follows successively in the range of 250 to 320 K. For comparison, we measured TPD of the unloaded carrier DPM showing dehydrogenation at the CH2 group above 310 K, leading to the first decomposition product. Upon further heating up to 800 K complete decomposition to carbon fragments happens.