Formation of oxide nanotubes via oxidation of Fe, Cu and Ni nanowires and their structural stability: Difference in formation and shrinkage behavior of interior pores
✍ Scribed by R. Nakamura; G. Matsubayashi; H. Tsuchiya; S. Fujimoto; H. Nakajima
- Publisher
- Elsevier Science
- Year
- 2009
- Tongue
- English
- Weight
- 494 KB
- Volume
- 57
- Category
- Article
- ISSN
- 1359-6454
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✦ Synopsis
Changes in the morphology of Fe, Cu and Ni nanowires with a diameter of 55 nm during oxidation at 423-923 K were studied by transmission electron microscopy. Oxide nanotubes with a cylindrical interior pore of uniform diameter were formed after the oxidation of Fe and Cu nanowires in air at 573 and 423 K, respectively, while the Ni nanowires became bamboo-like nanowires of NiO with separate interior voids after oxidation at 673-773 K. Oxide nanotubes of Fe and Cu and the bamboo structures of NiO showed a tendency to shrink into solid oxide nanowires after annealing at higher temperatures in air. In the shrinking process of Fe 3 O 4 nanotubes, however, an array of additional nanovoids was observed along the inner wall of the nanotubes, suggesting the formation of a duplex porous nanostructure. This can be explained by the recombination of vacancies diffusing outward from the inner cylindrical pore.