HRTEM images

Fig. 13. HRTEM image of an as-grown thick PCNT. 002 lattice image demonstrates the innermost hollow core (core diam. 2.13 nm) presumably corresponding to the as-formed nanotube. The straight and continuous innermost two fringes similar to Fig. 5 are seen (arrow).

In Fig. 1 is shown a HRTEM image of part of the end of a PCNT. The initial material consisted of carbon nanotubes upon which bi-conical spindle-like secondary growth had deposited[21], apparently by inhomogeneous deposition of aromatic carbonaceous, presumably disordered, layers on the primary substrate nanotube. Prior to further heat treatment, the second-... 

Similar results were found by Bacsa el al. [26] for cathode core material. Raman scattering spectra were reported by these authors for material shown in these figures, and these results are discussed below. Their HRTEM images showed that heating core material in air induces a clear reduction in the relative abundance of the carbon nanoparticles. The Raman spectrum of these nanoparticles would be expected to resemble an intermediate between a strongly disordered carbon black synthesized at 850°C (Fig. 2d) and that of carbon black graphitized in an inert atmosphere at 2820°C (Fig. 2c). As discussed above in section 2, the small particle size, as well as structural disorder in the small particles (dia. —200 A), activates the D-band Raman scattering near 1350 cm . ... 

The length and the diameter of MWCNT can be measured directly by TEM. From high-resolution transmission electron microscopy (HRTEM) images exhibiting oo.l fringes follows the number of coaxial tubes and possibly the microstructure of the caps in MWCNT, as viewed along the incident electron beam [24], Also anomalous intercylinder spacings and defects are revealed in this way [1,11]. 

Figure I HRTEM images of the (a) 14M and (b) Llo martensite in Ni-Al including the corresponding SAED patterns.

Figure 2 [001] HRTEM images of the austenite with static precursor distortions observed prior to the (a) 14M and (b) LIq transformation in Ni-Al. The position of the satellite for (a) is indicated in the inset.

Figure 3 (a) [001] HRTEM image of the distorted austenite of figure 4 after (a) 1 min. and (b) 5 min. irradiation with 400 keV electrons inside the microscope. The increase of the modulation amplitude is apparent. The line in (b) indicates an interface between two adjacent martensite variants. 

Figure 6 [001] HRTEM image of the distorted austenite of L2i Ni2MnGa Heusler alloy clearly revealing modulated ISO s. The modulation wavelength is appr. 6(110) planes (courtesy Zheludev et al. ).

Figure 8 HRTEM image of the ineommensurately modulated phase observed at room temperature in Ti5oPd43Cr7- The modulations can be described by a sinusoidal wave with wave-vector 0.31 [IlOJbcc (courtesy Schwartz et al. )...

Fig. 6. Typical representative of the TEM image (A), and HRTEM image (B) of PVP -capped nanoparticles.

Figure 11 (a) [13] shows the cross section of HRTEM image of the tested specimen. Amorphous silicon area occurs... 

Ag-core/Au-shell bimetallic nanoparticles were prepared by NaBH4 reduction method [124]. UV-Vis spectra were recorded and compared with various ratios of AuAg alloy nanoparticles. The UV-Vis spectra of bimetallic nanoparticles suggested the formation of core/shell structure. Furthermore, the high-resolution transmission electron microscopy (HRTEM) image of the nanoparticles confirmed the core/shell type configuration directly. 

Figure 4. TEM and HRTEM images of (a) 6.5 nm Co nanoparticles and (b) Co-core/Au-shell nanoparticles using Co nanoparticles as the seed material. Lattice distances measured by HRTEM as well-matched to known Au lattice parameters for the (111) plane (inset). The average size of the Co-core/Au-shell nanoparticles is ca. 6.4 nm, which is similar to the initial size of the Co nanoparticles because the atom exchange process is the only operative reaction. (Reprinted from Ref [145], 2005, with permission from American Chemical...

It is noteworthy that the HRTEM cannot distinguish core and shell even by combining X-ray or electron diffraction techniques for some small nanoparticles. If the shell epitaxially grows on the core in the case of two kinds of metals with same crystal type and little difference of lattice constant, the precise structure of the bimetallic nanoparticles cannot be well characterized by the present technique. Hodak et al. [153] investigated Au-core/Ag-shell or Ag-core/Au-shell bimetallic nanoparticles. They confirmed that Au shell forms on Ag core by the epitaxial growth. In the TEM observations, the core/shell structures of Ag/Au nanoparticles are not clear even in the HRTEM images in this case (Figure 7). 

Figure 4. TEM images of the (a) Pt cubes, (b) Pt cuboctahedra, and (c) Pt octahedra. Inset images are corresponding HRTEM images and ideal structural models [15]. (Reprinted from Ref. [15], 2005, with permission from American Chemical Society.)...

Figure 8. HRTEM image of Au-ln/ZnO (left), and surface model (right). Indium preferentially decorates the outer faces of the gold particles while the edges remain uncovered. (Reprinted from P. Claus, Appl. Catal. A General 291 (2005) 222, 2005, with permission from Elsevier).

Figure 5. TEM images of nearly perfectly ordered hexagonal close-packed monolayers of (a) 1.5nm TCgBIP-Au and (b) 1.6nm TCgBIP-Au nanoparticles. Insets show FFT spots of each monolayer, (c) HRTEM image of 1.5 nm TCgBIP-Au nanoparticles. (Reprinted from Ref. [12], 2006, American Chemical Society.)...

Similarly, monometallic Rh, Pd, and Au and bimetallic Pt-Rh and Pt-Pd nanowires were prepared in FSM-16 or HMM-1 by the photoreduction method [30,33,34]. The bimetallic wires gave lattice fringes in the HRTEM images, and the EDX analysis indicated the homogeneous composition of the two metals. These results show that the wires are alloys of Pt-Rh and Pt-Pd. Mesoporous silica films were also used as a template for the synthesis of uniform metal particles and wires in the channels [35,36]. Recently, highly ordered Pt nanodot arrays were synthesized in a mesoporous silica thin film with cubic symmetry by the photoreduction method [37]. The... 

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