| Pacific Rim Symposium on Surfaces, Coatings and Interfaces (PacSurf 2014) | |
| Energy Harvesting & Storage | Wednesday Sessions |
| Session EH-WeM |
| Session: | Characterization of Materials for Energy Applications I |
| Presenter: | Gianluigi Botton, McMaster University, Canada |
| Correspondent: | Click to Email |
Electron Microscopy and electron energy loss spectroscopy are invaluable techniques to study the detailed structure and the chemical state of materials at unprecedented spatial resolution. In today’s modern electron microscopes, it is possible to tackle problems requiring the highest energy resolution, down to 60meV, and highest spatial resolution, down to the angstrom level, so that atomic resolved spectroscopy with high spectroscopic sensitivity and resolution can be obtained. This leads to the potential of covering excitation phenomena from the mid-infrared, soft-X-rays and even hard-X-ray regime.
In this presentation, various examples of applications of electron microscopy will be given based on a modern electron microscope. After an overview of the imaging conditions used to detect core-shell ordering changes in PtFe, PtRu, PtAu alloy nanoparticles [1,2] graphene and single atoms on doped graphene [3] used for fuel cell catalysts, using a combination of high-angle annular dark-field STEM imaging, EELS elemental mapping and simulations, we will discuss the application of atomic-resolved EELS mapping in to study complex oxide and oxide support materials used to promote strong metal support interaction [4]. Here we demonstrate how electron energy loss spectroscopy can be used to probe the valence change of the oxide following the interaction with the catalyst. This powerful technique can also be used to study of the structure and substitutional effects from single atom dopants in phosphors [5] and metallic alloys.
Additional examples will highlight the application of microscopy technique to the analysis of perovskite structures. These examples demonstrate that compositional and chemical state (valence and coordination) information can be obtained down to the Ångstrom level on surfaces [6].
References
1) S. Prabhudev et al., ACS Nano 7, 6103-6110, (2013),
2) M.C.Y Chan, L.Chen, F.Nan, J.F. Britten, C. Bock, G.A. Botton, Nanoscale 4, 7273 (2012)
3) S. Stambula et al., Journal of Physical Chemistry C, on-line (2014), DOI: 10.1021/jp408979h
4) M. Jaksic et al, J. Phys. Chem C. (2014) dx.doi.org/10.1021/jp412292w
5) G. Z. Zhu; Lazar, S.; Knights, A. P.; Botton, G. A., Physical Chemistry Chemical Physics 15, 11420-11426. (2013);
6) G.-Z. Zhu, G. Radtke, G.A. Botton, Nature, 490, 384, (2012)