Synthesis of TiO2/SiO2 core/shell nanocable arrays

Silica sheathed titania nanocable arrays were synthesized on Si substrates by using a vapor phase method. The morphology, microstructure, and chemical composition of the nanocables were characterized by using scanning electron microscopy, transmission electron microscopy, and spatial-resolution energy-dispersive X-ray spectroscopy, respectively. Raman spectroscopy combined with the other characterization methods elucidates that the nanocable core is of rutile titania. X-ray photoelectron spectroscopy indicates the existence of Ti-O-Si bonds as well as Ti-O-Ti and Si-O-Si bonds. A possible growth mechanism of the nanocables was also proposed on the basis of thermodynamic and kinetic considerations. The as-grown nanocable arrays may find applications as photocatalysts.