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MM: Fachverband Metall- und Materialphysik

MM 44: Topical Session: TEM-Symposium - In-Situ II

MM 44.3: Vortrag

Mittwoch, 13. März 2013, 17:15–17:30, H25

Dynamic atomic-scale observation of catalysts in their functional state by aberration-corrected environmental transmission electron microscopy (ETEM) — •Joerg Jinschek — FEI Company, Eindhoven, The Netherlands

Currently the strong focus on energy producing and environmental protecting technologies relies on the advancement of new functional catalysts. Characterization of the state and properties as well as catalyst*s performance demands detailed dynamic atomic-scale insights while in operation conditions [1]. The implementation of differential pumping apertures in an aberration corrected TEM (FEI Titan ETEM) enables to maintain high-resolution imaging and analytical capabilities, while confining a gas environment in the close vicinity of the catalyst specimen. Atomic-scale imaging in ETEM has opened up a unique possibility to monitor heterogeneous catalysts during exposure to reactive gas environments and temperatures [2]. As an example, a catalyst composed of Au nanoparticles supported on CeO2 , active for the oxidation of carbon monoxide (CO) even below room temperature, has been examined utilizing Titan ETEM [3]. The results of in situ HRTEM experiments depict that adsorbed CO molecules cause the Au{100} facets of a gold nanoparticle to reconstruct to Au{100}-hex. The energetic favorability of this reconstructed structure has been confirmed by ab initio calculations [3]. [1] P. L. Hansen et al. Science 295, 2053 (2002); [2] J.R. Jinschek, S Helveg. Micron 43, 1156 (2012); [3] H. Yoshida, et al. Science 335, 317 (2012)