SurfaceScience21 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 90: Poster Session VII: Surface reactions I

O 90.4: Poster

Donnerstag, 4. März 2021, 10:30–12:30, P

Temperature-dependent decomposition reactions of oxygen-containing LOHC contaminants on Pt(111) — •Valentin Schwaab, Johann Steinhauer, Felix Hemauer, Eva Marie Freiberger, Natalie Waleska, Christian Papp, and Hans-Peter Steinrück — Friedrich-Alexander-Universität, Erlangen, Germany

Liquid organic hydrogen carriers (LOHCs) represent an attractive way for energy storage and transportation utilizing reversible hydrogenation of an organic compound. The system of dibenzyltoluene (H0-DBT) and perhydro dibenzyltoluene (H18-DBT) has been reported as promising candidate featuring suitable physicochemical properties and a favorable toxicology. Technical H0-DBT, however, contains up to 1% of oxygenate impurities, which might negatively affect the quality of the released H2 gas from the hydrogenated molecule.

To gain insight in the surface reaction of these oxygenates, we investigated several model compounds on Pt(111) using high-resolution temperature-programmed X-ray photoelectron spectroscopy (HR-TPXPS). Diphenylmethanol, benzophenone and dicyclohexylmethanol are found to undergo C-O bond cleavage at the methylene bridge around 350 K, leading to an oxygen-free carbon fragment and adsorbed atomic oxygen. By contrast, dicyclohexylketone shows C-C bond cleavage and the formation of carbon monoxide above 220 K.

CO represents a catalyst poison and is problematic for further applications of the released H2 gas. A possible solution might be pre-purification of industrially produced H0-DBT.