(b) Structure of the nanotubes during stretching.
Both treatments preserve the structure of the nanotubes.
HRTEM analyses were performed on Cu2S-1 h nanotubes to obtain detailed information regarding the structure of the nanotubes.
All the samples were prepared without destroying the alignment structure of the nanotubes.
A JEOL-2100 transmission electron microscope (TEM; JEOL Ltd., Akishima, Tokyo, Japan) was used to check the structure of the nanotubes.
The TEM images of the product are shown in Fig. 2. Similar to SEM observation, the bamboo structure of the nanotubes with clean surface and uniform diameter along the nanotube length can be clearly seen (Fig. 2a).
The structure of the nanotubes was studied by transmission electron microscopy (TEM) technique using a JOEL 2100 microscope (JEOL Ltd., Akishima-shi, Japan) operated at the electron beam energy of 200 keV.
The adsorption-desorption isotherm contained an obvious H2-type hysteresis loop with a highly delayed desorption branch resulted from the hollow structure of the nanotubes, which were in accordance with the HRTEM images of Fig. 1.
The periodic diffraction indicates the bilayer structure of the nanotubes, and the nearest distance between two adjacent walls is in the range of 3.384 ± 0.010 nm, in accord with our previous work [12].
Sample rotation studies inside the transmission electron microscope show that the catalyst nanoparticles have a cylindrical rather than a rectangular shape, indicating that the flattened structure of the nanotubes is not templated by the shape of the catalyst particles.
It is reported that the superlative mechanical properties of these nano-structures, i.e. high stiffness, high strength and vibrational response, would be affected by existing or introducing defects and impurities in the structure of the nanotubes.
