inorganic nanotube
(rus. нанотрубка, неорганическая otherwise неуглеродная нанотрубка)
— a hollow quasi-one-dimensional structure with diameter ranging between 5 and 100 nm comprised of inorganic substances and materials.
Description
The first non-carbon nanotubes, made from WS2, were produced in 1992 [1]. Today, we have learned to produce nanotubes based on oxides and sulphides of d-elements (WS2, MoS2, TiO2, VOx, CuO, Al2O3, SiO2, etc.), as well as on nitrides (BN).
Non-carbon nanotubes can be produced using the template technique [2], vapour deposition, hydrothermal treatment [3], etc.
An external template (see fig.) based on mesoporous aluminium oxide, polycarbonate membranes and other materials can be used to produce tubular structures with different compositions, but the wall of such a nanotube will not be made of a monocrystal.
The hydrothermal treatment technique can be used to produce multiwall oxide- and sulphide-based nanotubes of a 3D → 2D → 1D model. For example, a three-dimensional crystal TiO2 reacts with an alkaline solution to form a lamellar two-dimensional (2D) structure that bends to converge dangling bonds of edge atoms. As it bends further, a scroll- or tube-like structure forms, made up of coaxial cylinders inserted one into another. In general, the end product is a combination of both forms of nanotubulenes.
Unlike in carbon nanotubes, the ends of nanotubulenes always remain open, due to their formation process.
Nanotubular structures may also develop by anode oxidation (see anodizing) of certain metals in reaction with reagents capable of selective dissolution of the oxide film. After the rapid initial formation of an oxide layer on the metal's surface, the oxide formation and dissolution (etching) processes proceed at relatively equal rates. Etching is most intensive around the faults and irregularities of the oxide film; the oxide etching rate at the tip of a pore is also greater than at its mouth, resulting in the formation of a system of cylindrical pores that sometimes take up the entire thickness of the oxide film.
Depending on their morphology, specific surface and features of the base material’s crystalline and electric structure, non-carbon nanotubes can be used as sensors in sensory devices or as electrode materials in new chemical current sources [3,4].
Non-carbon nanotubes can be produced using the template technique [2], vapour deposition, hydrothermal treatment [3], etc.
An external template (see fig.) based on mesoporous aluminium oxide, polycarbonate membranes and other materials can be used to produce tubular structures with different compositions, but the wall of such a nanotube will not be made of a monocrystal.
The hydrothermal treatment technique can be used to produce multiwall oxide- and sulphide-based nanotubes of a 3D → 2D → 1D model. For example, a three-dimensional crystal TiO2 reacts with an alkaline solution to form a lamellar two-dimensional (2D) structure that bends to converge dangling bonds of edge atoms. As it bends further, a scroll- or tube-like structure forms, made up of coaxial cylinders inserted one into another. In general, the end product is a combination of both forms of nanotubulenes.
Unlike in carbon nanotubes, the ends of nanotubulenes always remain open, due to their formation process.
Nanotubular structures may also develop by anode oxidation (see anodizing) of certain metals in reaction with reagents capable of selective dissolution of the oxide film. After the rapid initial formation of an oxide layer on the metal's surface, the oxide formation and dissolution (etching) processes proceed at relatively equal rates. Etching is most intensive around the faults and irregularities of the oxide film; the oxide etching rate at the tip of a pore is also greater than at its mouth, resulting in the formation of a system of cylindrical pores that sometimes take up the entire thickness of the oxide film.
Depending on their morphology, specific surface and features of the base material’s crystalline and electric structure, non-carbon nanotubes can be used as sensors in sensory devices or as electrode materials in new chemical current sources [3,4].
Illustrations
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Vanadium oxide nanotube on basis of vanadium oxide derived by hydrothermal treatment of crystalline vanadium oxide with hexadecilamine-1 used as a molecular template. Authors: A. V. Grigorieva, Evgeny A. Goodilin, Lomonosov Moscow State University, Department of Materials Science [6]. © Elsevier Limited. |
Authors
- Shlyakhtin Oleg A.
- Goldt Anastasia E.
Sources
- Tenne R., Margulis L., Genut M., Hodes G. Polyhedral and cylindrical structures of tungsten disulphide // Nature. 1992. V. 360. P. 444.
- Ogihara H., Sadakane M., Nodasaka Y., Ueda W. Shape-Controlled Synthesis of ZrO2, Al2O3, and SiO2 Nanotubes Using Carbon Nanofibers as Templates // Chem. Mater. 2006. V. 18, №21. P. 4981.
- Nanotechnologies. ABC for everyone(in Russian) // Ed. by Tret'jakov Ju. D. — Moscow: Fizmatlit, 2008. — 368 p.
- A.V. Grigor’eva at all. Micromorphology and structure of vanadium oxide nanotubes (V) // Doklady Akademii Nauk. 2006. Vol. 410, №4. 482–486 pp.
- Tenne R. Inorganic Nanotube Materials // Encyclopedia of Materials: Science and Technology. — Elsevier Science Ltd, 2000. —www.elsevier.com/homepage/sai/emsatinfo/site/Emsat_re/site/PDFsamples/emr509020.pdf
- Grigorieva A. V., Goodilin E. A., Anikina A. V. et al. Surfactants in the formation of vanadium oxide nanotubes // Mendeleev Communications. 2008. V. 18, №2. P. 72.