From Single-Component Nanowires to Composite Nanotubes

In this work, a facile, solution phase route using Co(OH)(x)(CO3)(y) nanowires as precursors was developed to fabricate SnO2/Co(OH)(x+2 epsilon)(CO3)(y-epsilon), and then they were transformed into SnO2/Co3O4 composite nanotubes by a simple thermal treatment process, which had great advantages in controlling their elemental ratios and the size of inner diameters. The mechanism is systematically discussed, which offers a clue that diffusion could be used as a driving force for the formation of nanotubes with different components, and single-component nanowires with replaceable negative ions may serve as good building blocks. TiO2/Co3O4 nanotubes were also successfully achieved to demonstrate the generality of the methodology, which is helpful for scientists to exploit novel functional materials with new properties and applications.