Conversion of Metal Oxide Nanosheets into Nanotubes

Abstract

In this chapter, structural relationship and conversion between two-dimensional (2D) nanosheets and one-dimensional (1D) nanotubes are reviewed. Nanotubes are spontaneously formed upon exfoliation of certain layered materials with a non-centrosymmetric or particular structure, such as K4Nb6O17 and some perovskite-type Ruddlesden-Popper phase K2[An-1BnO3n+1](A = Na, Ca, Sr, La; B = Ta, Ti). On the other hand, colloidal centrosymmetric nanosheets represented by titanium oxide, manganese oxide, and calcium niobium oxide can also be success-fully converted into their corresponding nanotubes through a simple ion intercalation/deintercalation procedure at ambient temperature. The conversion validates the hypothesis, in which directly rolling a nanosheet yields a nanotube. The close relationship is of fundamental importance in revealing the formation mechanism of nanotubes and may be used to realize a customized synthesis of nanotubes from a wide range of layered materials. © Springer-Verlag Berlin Heidelberg 2010.