Regensburg 2022 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 52: Poster Wednesday: Adsorption and Catalysis 2
O 52.7: Poster
Mittwoch, 7. September 2022, 18:00–20:00, P4
2D arrays of reaction centers for CO oxidation over Pt/SiO2/Si interface — •Artur Böttcher1, David Rettinger1, Jakob Hauns1, Manfred Kappes1, Daniela Exner2, Rahul Parmer3, Matteo Amati3, and Luca Gregoratti3 — 1Institute of Physical Chemistry, KIT, 76131 Karlsruhe, Germany — 2Institute for Applied Materials, KIT, 76344 Karlsruhe, Germany — 3Elettra - Sincrotrone Trieste ScPA, Area Science Park, 34149 Basovizza-Trieste, Italy
We created arrays of tailored reaction centers on the SiO2/Si-wafer by annealing thin Pt layers deposited on He+-beam patterned Graphene/SiO2/Si substrates.[1] The resulting spots have been identified as amorphous areas consisting of silicon carbides and silicon oxycarbides. These defected surface regions are expected to act as pinning sites for migrating Pt atoms. By thermally activating the surface diffusion of Pt adatoms (1h, 600°C, UHV), the migrating atoms become immobilized thus forming chemical bonds with compounds created in the defected surface regions, resulting in 2D arrays of tailored Pt-based islands. The chemical state of individual islands has been studied by monitoring core level states (ESCA microscopy). The islands consist of Pt, PtSix and PtOx compounds and appear to be chemically resistant under exposure to molecular oxygen and carbon monoxide at T=550°C, p= 0.4 mbar, 0.5 h. The CO2-light-off curves enable to estimate the contribution of the artificial reaction centers to the total CO->CO2 conversion yield.
[1] A. Böttcher et al. 2020 Nanotechnology 31 505302