Preparation of helical titania nanotubes using a sol-gel transcription approach

Titania nanoparticles have attracted much attention for their application in catalysis. Over the last few decades, studies have shown that their morphology can be carefully controlled. However, reports on the preparation of helical titania nanotubes are rare. Here, a pair of valine-derived chiral cationic gelators were synthesized, which could self-assemble into helical nanofibers in ethanol and isopropanol. Single-handed helical titania nanotubes were prepared using a sol-gel transcription approach, using the self-assembly of the gelators as a template. The results indicated that the handedness of the titania nanotubes was controlled by that of the organic self-assembled structures. Transmission electron microscopy images indicated that the nanotubes were constructed from nanocrystals. Wide-angle X-ray diffraction patterns indicated that the nanocrystals were anatase. Because the space group of anatase phases is chiral, the titania nanotubes have the potential to be used as asymmetric catalysts, and chirality sensors. (C) 2012 Elsevier B.V. All rights reserved.