High-resolution transmission electron microscopy , inorganic

The calcined samples are investigated by transmission electron microscopy (TEM) in a Philips EM 420 instrument operated at 120 kV. The specimens are deposited on a copper grid coated with a carbon film. High-resolution transmission electron microscopy (HRTEM) has been carried out at the Laboratory of Inorganic Chemistry, ETH Zurich, Switzerland, with a Philips CM20-ST microscope (accelerating voltage 300 kV). 

Ag2S was also effectively stabilized by cysteinyl ligands. These clusters are synthesized using a molar ratio of 2 1 cysteine silver ions upon which stoichiometric amounts of inorganic sulfide were added to nucleate the nanoparticle, with subsequent size-selective precipitation. The resultant nanoparticles had an absorbance shoulder at 300 nm. Further analysis using high-resolution transmission electron microscopy (HRTEM) revealed a particle size of approximately 9.00 2.25 run in diameter. Selected area electron diffraction (SAED) analysis also demonstrates the highly crystalline natme of the product. ... 

Figure 18 shows a high resolution, transmission electron microscopy image of the mesoporous inorganic oxide support with embedded Zeolite Beta, and an inset showing an electron diffraction ( ED ) pattern of the zeolite domain (27). The ED pattern clearly shows that the Zeolite Beta has retained its crystallinity. 

Transmission electron microscopy (TEM) is also widely employed, in its simplest bright-field mode, as a tool for direct visualization of the nanocomposite structure of polymer nanocomposites. This is possible because there exists sufficient contrast for the transmitted electrons between the polymer matrix and most fillers (inorganic particles, carbon in nanotubes or graphite, and almost all oxides) without polymer staining. In the extreme case, high-resolution TEM can even provide a qualitative picture of the inorganic filler crystal structure, or can be... 

The electron microscopes can be divided into two types (166) scanning electron microscopes (SEM), which use a 10-nm electron beam at the specimen surface, and transmission electron microscopes (TEM). With current TEMs, resolution of about 0.2 nm can be achieved, provided very thin (<20 nm) samples are available. With conventional inorganic oxide-supported metal catalysts, particles of approximately 1 nm can be detected. Scanning transmission electron microscopes (STEM) use a high brightness dark-field emission gun to produce a probe about 0.3 nm in diameter and combine the techniques of SEM and TEM. Further experimental and theoretical aspects of electron microscopy applied to catalysis have been reviewed recently (113, 167-169). 

This chapter outlines how the recent advancements in transmission electron microscope instrumentation have provided new opportunities for high resolution characterisation of inorganic nanoparticle systems. Concentrating on the smallest nanoclusters, nanocrystals and nanoparticles with diameters of 1-50 nm we outline how the development of aberration correcting lenses,brighter, more coherent electron sources, and smarter, more efficient detector systems, has improved electron microscopy imaging and analysis at the nanoscale. 

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