Transmission electron microscopy nanostructured morphology

High-resolution transmission electron microscopy (HRTEM) has matured markedly in the preceding decade and has emerged as a powerful technique for investigation of nanostructured metal catalysts at the atomic level, even under working conditions. The ability to image the dynamic structure and morphology of supported metal nanocluster catalysts in such detail makes HRTEM an essential complement to the arsenal of spectroscopic techniques used for characterization of... 

For the comprehension of mechanisms involved in the appearance of novel properties in polymer-emhedded metal nanostructures, their characterization represents the fundamental starting point. The microstructural characterization of nanohllers and nanocomposite materials is performed mainly by transmission electron microscopy (TEM), large-angle X-ray diffraction (XRD), and optical spectroscopy (UV-Vis). These three techniques are very effective in determining particle morphology, crystal structure, composition, and particle size. 

A cross-sectional transmission electron microscopy (TEM) image of a material with predetermined morphology of spherical pores was examined. The structure consists of an interfacial layer, structural layer, and a substrate. The substrate is in direct mechanical contact with the interfacial layer. The structural layer is composed of spherical nanopores nanostructure, and essentially consists of the cross-linkable polymer. The interfacial layer lacks the spherical nanopores. The thickness of the interfacial layer is 2-30 nm. The structural layer thickness is of the range 50-300 nm. 

Two approaches for the synthesis of nanostructured M50 type steel (composed of 4.0% Cr, 4.5% Mo, 1.0% V, 0.8% C and balance Fe) powders and their consolidation are reported in this chapter. One approach involved the sonochemical decomposition of organometallic precursors and the other involved the reduction of the metal halides with lithium triethyl borohydride followed by vaccum sublimation of the powders to remove lithium chloride. The as-synthesized powders are amorphous by X-ray diffraction (XRD) but the peaks corresponding to bcc a-Fe are observed in the compacts. The morphology and composition of the powders synthesized by both techniques, as well as the compacts, were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Hardness, density, particle size and impurity contents were also determined for the compacts. In addition, pure nanosized iron particles obtained by the ultrasound decompositon of iron pentacarbonyl were consolidated and the properties of the latter were studied. 

Other studies performed on silver nanostructures with distinct morphologies have demonstrated that AgNPs undergo a shape-dependent interaction with bacteria (Pal et al. 2007). Transmission electron microscopy evaluations of bacteria surface showed that spherical NPs exhibit enhanced antibacterial activity than, for example, Ag nanorods. This effect was explained by the higher reactivity of fliese... 

X-ray diffraction technique is a non-destructive analytical technique that reveals information about crystallographic structure, chemical composition and physical properties of nanostructured materials. UV/Vis spectroscopy is routinely used in the quantitative determination of films of nanostructured metal oxides. The size, shape (nanocomb and nanorods etc,) and arrangement of the nanoparticles can be observed through transmission electron microscope (TEM) studies. Surface morphology of nanostructured metal oxides can be observed in atomic force microscopy (AFM) and scanning electron microscopy (SEM) studies. 

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