Regensburg 2022 – scientific programme

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MA: Fachverband Magnetismus

MA 39: Magnetic Particles / Clusters

MA 39.4: Talk

Friday, September 9, 2022, 10:15–10:30, H47

Effect of laser treatment on catalyst materials investigated by Mössbauer spectroscopy — •Soma Salamon¹, Joachim Landers¹, Swen Zerebecki², Sven Reichenberger², Stephan Barcikowski², and Heiko Wende¹ — ¹Faculty of Physics and CENIDE, University of Duisburg-Essen — ²Institute for Technical Chemistry I and CENIDE, University of Duisburg-Essen

Mössbauer spectroscopy is utilized as a non-destructive, element-specific measurement method to probe hyperfine interactions in spinels that are promising candidates for application in electrocatalysis. By recording low temperature (4.3 K) high field (5-10 T) spectra, it is possible to discern individual contributions from tetrahedrally and octahedrally coordinated crystallographic sites found in the spinel lattice of materials such as CoFe₂O₄, enabling access to the degree of inversion. Latter provides the distribution of Fe ions across these sites, while also allowing insight regarding the displacement of other ions within the lattice. This enables us to correlate changes in ion distribution in the lattice with improvements in catalytic activity, also giving clues about which ions on which positions serve as active sites during catalysis. Our results show that single-pulse laser excitation can selectively modify the ion distribution, while leaving the particles and their morphology largely intact. Further experiments also include tests of laser-induced diffusion of Fe into Co₃O₄ particles, with the use of isotope-pure ⁵⁷Fe allowing Mössbauer experiments to be performed on samples that do not normally contain any Fe. Funding by the DFG via the CRC/TRR 247 (ID 388390466, Projects B2, C5) is acknowledged.