https://scholars.lib.ntu.edu.tw/handle/123456789/409801
標題: | Dehydration, dehydroxylation, and rehydroxylation of single - Walled aluminosilicate nanotubes | 作者: | Kang D.-Y. Zang J. Wright E.R. McCanna A.L. Jones C.W. Nair S. |
關鍵字: | Aluminosilicate;Dehydration;Dehydroxylation;Inorganic nanotubes;Rehydroxylation | 公開日期: | 2010 | 卷: | 4 | 期: | 8 | 起(迄)頁: | 4897-4907 | 來源出版物: | ACS Nano | 摘要: | Single-walled metal oxide (aluminosilicate) nanotubes are excellent candidates for addressing the long-standing issue of functionalizing nanotube interiors, due to their high surface reactivity and controllable dimensions. However, functionalization of the nanotube interior is impeded by its high surface silanol density (9.1 -OH/nm2) and resulting hydrophilicity. Controlled dehydration of the nanotubes is critical for the success of functionalization efforts. We employ a range of solid-state characterization tools to elucidate dehydration and dehydroxylation phenomena in the nanotubes as a function of heat treatment up to 450 ¢XC. Vibrational spectroscopy (Fourier transform infrared, FT-IR), thermogravimetric analysis-mass spectrometry (TGA-MS), nitrogen physisorption, solid-state NMR, and X-ray diffraction (XRD) reveal that a completely dehydrated condition is achieved at 250 ¢XC under vacuum and that the maximum pore volume is achieved at 300 ¢XC under vacuum due to partial dehydroxylation of the dehydrated nanotube. Beyond 300¢XC, further dehydroxylation partially disorders the nanotube wall structure. However, a unique rehydroxylation mechanism can partially reverse these structural changes upon re-exposure to water vapor. Finally, detailed XRD simulations and experiments allow further insight into the nanotube packing, the dimensions, and the dependence of nanotube XRD patterns on the water content. ? 2010 American Chemical Society. |
URI: | https://scholars.lib.ntu.edu.tw/handle/123456789/409801 | ISSN: | 19360851 | DOI: | 10.1021/nn101211y |
顯示於: | 化學工程學系 |
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