Figure 10.

Schematic illustration of process to fabricate multiwall anatase TiO₂ nanotubes using negative template (a). SEM image of triple‐wall TiO₂ NTAs and sacrificial Al₂O₃ layers (b), and the broken ends of triple‐wall NTAs (c). TEM of a sextuple‐wall TiO₂ NTAs (d). TEM image of long quintuple‐wall NTs: the left inset is a representative electron diffraction pattern, and the right inset shows the separated TiO₂ walls (e). Reproduced with permission.168 Copyright 2009, American Chemical Society.