STEM-EELS

Finally, it was observed by STEM-EELS that a Co/Mn/Ti02 catalyst prepared by IWI clearly decreased the Co particle size after activation. Co particles of 5-10 nm were covered by MnO after reduction, and this was manifested in the F-T reaction as a decrease in activity. Hence, it was concluded that even when Mn is not mixed with the C03O4 in the calcined catalyst, upon reduction it may undergo changes, which lead to a covering and blocking of the small Co particles by the MnO phase. 

For appropriate comprehension of morphology and the concomitant structure-property correlations in nanocomposites, knowledge of the state and extent of nanofiller dispersion in the matrix is of paramount importance. Numerous methods have been reported in the literature in this regard, for instance, WAXD [6, 38], SAXS [8, 39], SANS [40], SEM, [6, 41], AFM [7, 42], HRTEM, STEM, EELS [43], SSNMR [44], EPRS [45], UV/vis/NIR, FTIR [46], Raman spectroscopy... 

Once the breakdown location is identified using DBIE, electron energy loss spectrometry (EELS) was performed using a FEI-TITAN 300 kV TEM/STEM to analyze the chemical nature of the percolation path [10,11]. Fig. 2 illustrates a close-up view of the sample configuration and beam-sample interaction. STEM/EELS spectra were collected at 80 keV beam voltage using point-to-point vertical and horizontal scans as shown in Fig. 2b across the dielectric layer at the breakdown site identified by a DBIE and at the non-breakdown site that were far away from the DBIE. 

Similar to the results shown in Figs. 4 and 5, STEM/EELS analysis is in progress to study the nature and chemistry of the breakdown path in advanced high-k based gate stacks. 

Figure 10. 3D-STEM, EELS and HR-TEM of cobalt on alumina catalysts in the oxide stage.

Fig. 3 Combining atomically resolved STEM EELS with modelling can reveal the bonding environment of individual atoms. DFT modelling of EELS near-edge fine structure shows that 3-fold coordinated Si impurities in graphene adopt a distorted, out of plane, geometry, while the bonding of 4-fold coordinated Si impurities is in-plane. Figure reprinted with permission from Q. M. Ramasse eta/.. Nano Lett., 2012, 13, 4989-4995. Copyright 2012 American Chemical Society.

Fig. 7.10 Electron microscopy images of Fe-ZSM-5. a STEM/EELS micrograph (Fe/O map) of...

There are two ways to collect spectrum image for a specimen one is using EETEM, another is using STEM-EELS. As show in Eig. 5.17, in EETEM mode, a 3D data set can be obtained by taking an EETEM image at each energy loss. In this case, the... 

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