Berlin 2015 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 11: Nanoparticles and Composite Materials II (joint CPP/BP)

BP 11.10: Vortrag

Montag, 16. März 2015, 17:30–17:45, C 243

Local Chemical Characterization of Nanoporous Materials with Atom Probe Tomography — •Carsten Nowak, Philipp Sauerbier, and Björn Pfeiffer — Georg-August-Universität Göttingen, Insitute for Materials Physics, Göttingen, Germany

Because of their high surface-to-volume-ratio and their chemical activity, nanoparticles and nanoporous materials receive a lot of interest in the areas of catalysis and electrochemistry. To obtain a detailed insight into reaction mechanisms, knowledge of the local chemical composition and structure, particularly at the surface of the material, is desirable.

Here we present experimental results on the local chemical characterization of nanoporous gold with atom probe tomography. The nanoporous gold with pore and ligament size of 50 nm, chosen as model system, is converted into a compact material by electron beam induced deposition of metalorganic precursors. Subsequently, the material is characterized with atom probe tomography which essentially is a combination of single molecule time of flight spectroscopy and atomic scale microscopy, thus allowing to characterize the local chemical composition of the filled material and particularly its former surface with sub-nanometer spatial resolution.

Although the preparation involves a chemical reaction of the surface with the precursor and thus alters the active surface of the nanoporous material, this approach offers the potential to detect chemical species at the surface of irregularly shaped nanoparticles with sub-monolayer sensitivity.