Berlin 2015 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 39: Heterogeneous Catalysis

O 39.5: Poster

Dienstag, 17. März 2015, 18:15–21:00, Poster A

Methanol Adsorption and Reaction on SmO_x/Pt(111) Systems Studied by TPD and IRRAS — •jin-hao jhang¹, andreas schaefer¹, jason f. weaver², and marcus bäumer¹ — ¹Institute of Applied and Physical Chemistry, Center for Environmental Research and Sustainable Technology, University of Bremen, Germany — ²Department of Chemical Engineering, University of Florida, USA

Samaria (SmO_x) as one of rare earth oxides has been considered as a promising oxide catalyst as it shows, for instance, high selectivity in the oxidative coupling of methane (OCM). Whereas other rare earth oxides such as ceria have been studied intensively, detailed investigations of the surface chemistry of SmO_x are still lacking. Here we used methanol (MeOH) as a smart probe molecule by means of temperature programmed desorption (TPD) and infrared reflection-absorption spectroscopy (IRRAS) to study the surface chemistry of SmO_x thin films which were grown on a Pt(111) substrate. TPD results show that CO and H₂ are main products of the MeOH reaction on SmO_x/Pt(111). Moreover, a cooperative effect by SmO_x and the Pt substrate is only observed on the non-fully covered SmO_x/Pt(111). Surprisingly CO₂ as an unexpected product is also found, and a measurable amount of hydrogen is missing. IRRAS results confirm the existence of methoxy and formate species during MeOH decomposition on SmO_x/Pt(111) which indicates the domination of the dehydrogenation process. Additionally, monitoring the shift of the C-O stretch frequency provides information about the adsorption sites of methoxy on SmO_x surfaces.