Director of the Nanocharacterization Laboratory, Center for Advanced Materials and
Nanotechnology, Lehigh University, Bethlehem, PA 18015-3195, USA.
The analytical electron microscope (AEM) is a tremendously powerful and versatile tool for characterizing the morphology, crystallography and chemical composition of heterogeneous catalyst materials. In this presentation the various imaging, diffraction and spectroscopic techniques available within the modern AEM will be reviewed. The different kinds of structural information available from bright field, annular dark field and high resolution lattice imaging will be compared and contrasted. Furthermore, the basic concepts behind HAADF 3D tomographic imaging for the study of nanoparticulate systems will be introduced. The use of convergent beam electron diffraction (CBED) and
Fourier Transform (FT) analysis to study the crystallography of individual particles will also be described. The possibilities and challenges for high spatial resolution composition analysis using the complementary techniques of energy dispersive X-ray spectroscopy
(XEDS) and electron energy loss spectroscopy (EELS) will be discussed. In particular, the special problems posed by the analysis of catalyst nanoparticles having core-shell morphologies will be explained. Finally, the practical significance of the new development of aberration corrected microscopy for the future of catalyst characterization will be discussed.