Dresden 2026 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 34: Catalysis and surface reactions I
O 34.6: Vortrag
Dienstag, 10. März 2026, 11:45–12:00, HSZ/0204
In situ X-ray Imaging of PtPd Core-Shell Nanoparticles under Methane Oxidation Conditions — •Lydia J. Bachmann1,2, Thomas F. Keller1,2, Ivan A. Vartanyants1, and Andreas Stierle1,2 — 1Deutsches Elektronen-Synchrotron DESY — 2University of Hamburg
Due to the high global warming potential of methane, the release of any methane into the atmosphere needs to be avoided. Therefore, catalysts are used for the emission control. Common catalyst nanoparticles (NPs) for methane oxidation consist of Pd or Pt. Combining them allows to build more stable NPs. Since the surface chemical composition is crucial for the activity, segregation and mixing processes need to be taken into account. In this study we successfully tuned the initial chemical composition of one core-shell and one partially alloyed NP. We confirmed these elemental distribution by Bragg coherent diffraction imaging (BCDI). During in situ BCDI measurements under methane oxidation at temperatures between 320°C and 560°C, Pt segregated to the {111} oriented facets of the initial core-shell NP. Conversely, the initially partially alloyed NP did not exhibit such facet-dependent segregation, but rather observed the formation of a Pd core, Pt shell structure at 680°C. Since the initial Pt core, Pd shell NP showed Pd-Pt mixing at 620°C, we hypothesize that this NP would form such an inverted core-shell structure under higher temperatures as well. These results demonstrate opportunities for systematically investigating promising core-shell NPs and their catalytic activity, offering valuable insights for the design of advanced catalysts.
Keywords: core-shell; nanoparticle; methane oxidation; segregation; BCDI