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Influence of gas atmospheres and ceria on the stability of nanoporous gold studied by environmental electron microscopy and in situ ptychography

Baier, Sina; Wittstock, Arne; Damsgaard, Christian D.; Diaz, Ana; Reinhardt, Juliane; Benzi, Federico; Shi, Junjie; Scherer, Torsten; Wang, Di; Kubel, Christian; Schroer, Christian G.; Grunwaldt, Jan-Dierk

Abstract (englisch): A novel complementary approach of electron microscopy/environmental TEM and in situ hard X-ray ptychography was used to study the thermally induced coarsening of nanoporous gold under different atmospheres, pressures and after ceria deposition. The temperature applied during ptychographic imaging was determined by IR thermography. While using elevated temperatures (room temperature – 400 °C) and realistic gas atmospheres (1 bar) we achieved for the first time a spatial resolution of about 20 nm during hard X-ray ptychography. The annealing of pure and ceria stabilized nanoporous gold in different atmospheres revealed that the conditions have a tremendous influence on the coarsening. The porous structure of the samples was stable up to approximately 800 °C in vacuum, whereas pronounced changes and coarsening were observed already at approximately 300 °C in oxygen containing atmospheres. A layer of ceria on the nanoporous gold led to an improvement of the stability, but did not alleviate the influence of the gas atmosphere. Different behaviors were observed, such as coarsening and even material loss or migration. The results suggest that additional mechanisms beyond surface diffusion need to be considered and that microscopic studies aimed at more realistic conditions are important to understand the behavior of such materials and catalysts.

Zugehörige Institution(en) am KIT Institut für Nanotechnologie (INT)
Karlsruhe Nano Micro Facility (KNMF)
Institut für Technische Chemie und Polymerchemie (ITCP)
Publikationstyp Zeitschriftenaufsatz
Jahr 2016
Sprache Englisch
Identifikator DOI: 10.1039/C6RA12853J
ISSN: 2046-2069
URN: urn:nbn:de:swb:90-590048
KITopen ID: 1000059004
HGF-Programm 43.22.02; LK 01
Erschienen in RSC Advances
Band 6
Seiten 83031-83043
Bemerkung zur Veröffentlichung Lizenz: Dieses Werk ist lizenziert unter CC BY-NC 3.0 DE
RSC geförderter Open Access-Artikel
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