Fritz-Haber-Institut der Max-Planck-Gesellschaft  

Inorganic Chemistry – Electron Microscopy Group
  

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Electron Microscopy Group:
Marc Willinger
 
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Ernst Ruska
 
Methods:
 
Covering a broad range of magnifications ranging from optical microscopy over scanning electron microscopy (SEM) and scanning transmission electron microscopy (STEM) down to sub angstrom resolution imaging using state of the art Cs corrected transmission electron microscopy (TEM), we study the structural characteristics of catalysts. Structural information is complemented with information about the elemental composition which is acquired using appropriate techniques for different size dimensions of the analyzed volume. The techniques range from X-ray fluorescence spectroscopy for average composition to energy dispersive X-ray (EDX) spectroscopy and EDX mapping in the electron microscope for more localized information. Furthermore, electron energy loss spectrometry (EELS) is used to provide further details about the elemental composition and electronic structure. Interpretation of the experimental data is supported by image simulations on the structure side and band structure calculation of the electronic structure and the simulation of EELS spectra on the other.
 
 

TEM

  • high resolution imaging
  • bright field/dark field imaging
  • selected area diffraction

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STEM

  • fast spot scanning
  • elemental mapping

(to see full size, click on the image)
 

EDX

  • qualitative and quantitative elemental analysis

(to see full size, click on the image)
 

EELS

  • qualitative elemental analysis
  • electronic structure

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Theory

  • density functional theory based calculations of the electronic structure
  • simulation of the finestructure in EELS spectra

(to see full size, click on the image)
 

Image simulation

  • particle shape
  • focal series reconstruction
  • high-resolution image simulation

(to see full size, click on the image)
 

SEM

  • Secondary Electron (SE) detector
    • low voltage imaging
    • surface morphology

  • Back Scattered Electron (BSE) detector
    • material contrast
    • topography

  • Diffractogramm Tableau
    • diffraction parameter
    • diffraction tableau
    • aberration

(to see full size, click on the image)


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Wavelength Dispersive X-Ray Fluorescence spectrometry (WDXRF)

  • qualitative and qunatitative analysis of powders and fluids

(to see full size, click on the image)
 

Sample preparation for Light Microscope, SEM, TEM, XRF

  • Separating:
    • Diamond wire saw
    • Diamond wheel saw
    • Ultramicrotome


  • Grinding:
    • Grinding and polishing machine
    • Dimple grinder


  • Ion beam thinning:
    • 3 Precision Ion Polishing Systems


  • XRF:
    • Fusion system for preparation as beads
    • Press technique

Ion beam thinning

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Ultramicrotome

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XRD

  • powder diffraction in transmission, Bragg-Brentano or parallel beam geometry
  • grazing incidence diffraction and reflectivity
 
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Address: Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany    
Abteilung Anorganische Chemie - Direktor Prof. Dr. Robert Schlögl    
Tel: +49 30 8413 4404, Fax: +49 30 8413 4401, E-Mail: acsek@fhi-berlin.mpg.de