- Titanium dioxide (B)
Titanium dioxide (B) or TiO2(B) is the
monoclinic form oftitanium dioxide . Themineral is found in weathering rims ontektite s andperovskite and aslamellae inanatase from hydrothermal veins [1] and has a density lower than that of the other three polymorphs.In the laboratory anatase can be converted in a hydrothermal route to TiO2(B)
nanotube s andnanowire s [2] which are of potential interest as catalytic supports and photocatalysts. For this to happen anatase is mixed with 15Msodium hydroxide and heated at 150 °C for 72 hours. The reaction product is washed with dilutehydrochloric acid and heated at 400 °C for another 15 hours. the yield of nanotubes is quantitative and the tubes have an outer diameter of 10 to 20nanometres and an inner diameter of 5 to 8 nanometres and have a length of 1micrometres . A higher reaction temperature (170 °C) and less reaction volume gives the corresponding nanowires.References
* [1] "Banfield, J. F., Veblen, D. R., and Smith, D. J. The identification of naturally occurring TiO2 (B) by structure determination using high-resolution electron microscopy, image simulation, and distance–least–squares refinement. American Mineralogist, 1991, 76, 343-353.
* [2] "Stem Cell Attachment to Layer-by-Layer Assembled TiO2 Nanoparticle Thin Films" Dinesh S. Kommireddy, Shashikanth M. Sriram, Yuri M. Lvov, David K. Mills, Biomaterials, 2006, 27, 4296-4303.
* [3] "Layer-by-Layer Assembly of TiO2 Nanoparticles for Stable Hydrophilic Biocompatible Coatings” Dinesh S. Kommireddy, Amish A. Patel, Tatsiana G. Shutava, David K. Mills, Yuri M. Lvov. Journal of Nanoscience and Nanotechnology, 2005, 5, 1081-1087.
* [4] "Nanotubes with the TiO2-B structure" Graham Armstrong, A. Robert Armstrong, Jesús Canales and Peter G. Bruce Chemical Communications, 2005, (19), 2454 - 2456 [http://www.rsc.org/publishing/journals/CC/article.asp?doi=b501883h Abstract]
* [5] "Titanium dioxide (TiO2) as photocatalyst", Green Quest Technology Inc. [http://www.greenquesttek.net/FAQ.html]
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