Dresden 2026 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 4: Energy Storage Materials and Devices I

CPP 4.3: Talk

Monday, March 9, 2026, 10:15–10:30, ZEU/0255

Electron Energy Loss Spectroscopy for oxidation state analysis on ammonia synthesis catalysts — •Daniela Ramermann, Michael Poschmann, 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 elemental compositions, 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, but the use of reference spectra improves the quantification results. In addition, it allows for the fitting of the edge shapes to investigate oxidation states with the spatial resolution of the electron microscope.

Because the available databases for EELS references [1] are not exhaustive, reference materials are obtained from acquired commercial materials of well-known and defined properties. It is crucial to thoroughly characterize these materials before measuring the reference spectra, as the materials may have local impurities or differ from the desired oxidation state. For the Fe-based catalyst system some reference materials are of mixed oxidation state, presenting an additional challenge.

We show the process of acquiring suitable EELS references for materials used in catalysis and the application of mapping the oxidation state and phase composition on a Fe based ammonia synthesis catalyst.

[1] https://eelsdb.eu, https://eels.info/atlas

Keywords: EELS; catalyst; oxidation state; ammonia