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MM: Fachverband Metall- und Materialphysik

MM 12: Materials for Storage and Conversion of Energy III

MM 12.2: Vortrag

Montag, 18. März 2024, 16:00–16:15, C 264

Application and pitfalls of self-measured EELS standards on a Cu based MeOH catalyst for oxidation state determination — •Daniela Ramermann, Lukas Pielsticker, Michael Poschmann, Christoph Göbel, Elisabeth H. Wolf, Holger Ruland, and Walid Hetaba — Max-Planck-Institut für Chemische Energiekonversion, Mülheim (Ruhr)

Electron energy loss spectroscopy (EELS) is a powerful technique, not only for the determination of the elemental composition, but also for the investigation of chemical bonding and oxidation states. For the analysis of EELS data, the use of cross-section models is quite common. However, the use of reference spectra (standards) improves the quantification results and in addition allows for the fitting of the edge shapes to investigate phase composition / oxidation states. Such standards are obtained from acquired materials of well-known and defined properties. There are several databases for EELS references [1], however, their content is not exhaustive.

To apply this principle on our samples, we obtained a set of well-defined materials for the acquisition of EELS reference data. As these materials may have local impurities and differ from the desired oxidation state, it is crucial to ensure that these materials are in a well-defined state. We show the process of acquiring suitable EELS standards for materials used in catalysis and the application of mapping the oxidation state and phase composition on a Cu based methanol synthesis catalyst.

[1] https://eelsdb.eu, https://eels.info/atlas, http://eel.geri.re.kr

Keywords: EELS; catalyst; oxidation state