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MM: Fachverband Metall- und Materialphysik
MM 29: Poster II
MM 29.27: Poster
Dienstag, 19. März 2024, 17:00–19:00, Poster B
In-situ/ Operando Electron Microscopy Characterization of model catalyst system for CO Oxidation — •Ajai Raj Lakshmi Nilayam1, Carina Maliakkal1, Ramin Shadkam1, Nicola Da Roit2, Di Wang1, and Christian Kübel1 — 1Institute of Nanotechnology — 2Institute of Catalysis Research and Technology, Karlsruhe Institute of Technology (KIT)
In-situ scanning transmission electron microscopy (STEM) study of model catalyst systems with size selected Pt clusters on nanostructured CeO2 can be of aid to track the structure and morphological changes of clusters and to understand the chemistry during various pretreatment and CO oxidation reaction conditions. Pt clusters prepared by physical vapour deposition (cluster ion beam deposition (CIBD) on pulsed laser deposited CeO2) and wet chemical synthesis (polyol reduction to form Pt17 cluster followed by incipient wetness impregnation with CeO2 nanorods/ nanocubes) are of interests in this study. In-situ STEM study of CIBD deposited Pt200 on in-situ STEM nanoreactor chip (with SiNx membrane as support) resulted in cluster coalescence while imaging in vacuum and O2 and Ar environment at 100°C and higher, showing that the clusters are unstable on SiNx, whereas the clusters supported on CeO2 are more stable and agglomerate only at higher e- dose rates. In H2 atmosphere, the clusters on CeO2 are more stable, and do not coalesce even after prolonged exposure to e- beam at 300°C. This could be explained by Pt-mediated reduction of CeO2 overcoming the kinetic barrier for the reduction of CeO2.[1] References [1] Selim Alayoglu et. al., J. Phys. Chem. C 2013, 117, (50), 26608*26616
Keywords: in-situ STEM; Pt cluster; CeO2; CO oxidation; catalysis