Unusually versatile and with depth: X-ray spectroscopy
© Paderborn University, Roland Schoch
The Bauer group is intensively involved in the application and further development of X-ray spectroscopic methods: X-ray absorption (XAS) and X-ray emission (XES).
By using hard X-rays at synchrotrons and free electron lasers in Germany and abroad (e.g. DESY, XFEL, Diamond, ESRF, SACLA), it is possible to investigate novel materials and compounds not only ex-situ but also in-situ or under operando conditions. The equipment is not limited to solids, so that samples in solution or suspensions can also be analysed under catalytic conditions (reaction gases/inert conditions, additional photophysical excitation, temperature-dependent measurements, reactions under overpressure, etc.).
© Paderborn University, Roland Schoch
By using XAS, HERFD-XANES (High energy resolution fluorescence detected X-ray absorption near edge structure), CtC-XES (core-to-core X-ray emission spectroscopy) and VtC-XES (valence-to-core XES), all relevant geometrical (bond lengths and coordination numbers) and electronic (spin multiplicity, HOMO and LUMO states) information can be obtained, which is necessary for a mechanistic understanding of the functioning of metal complexes and catalysts.Spectra interpretation is performed using classical evaluation programs as well as (TD-)DFT calculations. In addition to numerous exciting collaborations, we focus on the application of these methods to photoactive compounds, novel energy storage materials and noble metal-free catalyst alternatives for industrial applications.
© Paderborn University, Steffen Schlicher
In order to apply the new photon-in/photon-out spectroscopy methods such as HERFD-XANES, core-to-core XES (CtC-XES) and valence-to-core XES (VtC-XES) to our sustainable chemistry systems, technical developments are necessary. These concern both the core of the experiment - the spectrometer - and the sample environment - the measuring cells. In particular, the construction of new spectrometer types with different time resolutions at PETRA III is a core task of the group.
Selected publications from this field
Ultrafast Two‐Color X‐Ray Emission Spectroscopy Reveals Excited State Landscape in a Base Metal Dyad
M. Nowakowski, M. Huber‐Gedert, H. Elgabarty, A. Kalinko, J. Kubicki, A. Kertmen, N. Lindner, D. Khakhulin, F.A. Lima, T. Choi, M. Biednov, L. Schmitz, N. Piergies, P. Zalden, K. Kubicek, A. Rodriguez‐Fernandez, M.A. Salem, S.E. Canton, C. Bressler, T.D. Kühne, W. Gawelda, M. Bauer, Advanced Science (2024).
Insights into the First Multi-Transition-Metal Containing Ruddlesden Popper-Type Cathode for all-solid-state Fluoride Ion Batteries
V. Vanita, A.I. Waidha, S. Vasala, P. Puphal, R. Schoch, P. Glatzel, M. Bauer, O. Clemens, Journal of Materials Chemistry A (2024).
Hydrogen spillover through hydride transfer: the reaction of ZnO and ZrO2 with strong hydride donors
M. Benz, O. Bunjaku, M. Nowakowski, A. Allgaier, I. Biswas, J. van Slageren, M. Bauer, D.P. Estes, Catalysis Science & Technology 14 (2024) 5854–5863.
Detection and Characterization of Hydride Ligands in Copper Complexes by Hard X‐ray Spectroscopy
L. Fritsch, P. Rehsies, W. Barakat, D.P. Estes, M. Bauer, Chemistry – A European Journal 30 (2024).
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