| Carbon nanotubes (CNTs) is the typical one-dimensional (1D) nanomaterial which possess perfect structure. Owing to its special physical structure, outstanding performance and wide application, CNTs has been paid great attention. The chemical character of CNTs is very stable which could endure the violet acid, violet alkali and don’t be oxidated below700℃in air. Combining with remarkable performance. But CNTs is easy to agglomerate due to their high surface energy, which make the application of CNTs limited. So it is very hot that study the alterperformance and application of CNTs. In the paper, focusing on the preparation and the properties of CNTs nanocomposites, a series of working is as follows:(1)Silica nanotubes with one-dimensional structure have been synthesized by chemical method with temperature of550℃about5h, which used the multi-walled carbon nanotubes (MWCNTs) as the template, with Zn and SiCl4as reactant. The as-obtained samples were characterized by Transmission electron microscopy (TEM), the results indicate that silica nanotubes have a smooth-sided, the average diameter of silica nanotubes is in the range of40-60nm.The thickness of the outer walls is about5nm and the inner diameter is completely dependent on the size of the MWCNTs. The length of silica nanotube reach to micron level with higher aspect ratio.The BET surface area calculated from the results of nitrogen adsorption/desorption is156.229m2/g, which is much higher than that of MWCNTs used as template (1.540m2/g, measured by the same method). The larger BET surface area is due to the open ends and bigger inner diameters than that of MWCNTs, which is corresponding to the results of TEM observations. The as-fabricated silica nanotubes have a strong absorption peak at the wavelength of209nm and emit a strong violet light under excitation of461nm with the excitation light of350nm.(2)In the paper,we discussed the influence of chemical reaction parameters on the morphology of the sample. The silica tubes were characterized by X-ray diffraction, high-resolution transmission electronmicroscope (HR-TEM). Through the comparison of the samples which were acquired in different parameters conditions, we found that soaking temperatures, reaction time, the quality of CNTs have an important effect on the morphology of the obtained silica nanoparticles. An optimum experimental condition could be obtained, that is, the Si/Zn molar ratio of6.6:1, the quality of CNTs of0.5g, the temperature at550℃and the reaction time of5h. This approach is expected to provide a huge possibility for the industrialized manufacture of silica nanotubes.(3)According to the discussion of the process paramerers, we have established a model of the formation mechanism of silica nanotubes. The TEM shows that the yield of silica nanotubes are improved with the increasing of carbon nanotubes. The nanotubes are easily agglomerate when the quality of carbon nanotubes over a certain quantity. We can conclusion that nanoparticles deposited on the surface of CNTs and prepare the morphology successfully.This work was supported by the National Natural Science Foundation of China (Nos.50872072and51042005), Science and Technology Development Project of Shandong Province (Nos.2011GGX10205and2009GG10003003), and Independent Innovation Foundation of Shandong University (2009TS001and2012TS213). |
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