2.5. TEM Observations and In Situ TEM Observations at High
Temperature. The detailed nanotube structure was observed using
TEM (Hitachi, Model H-9500, 300 kV). The annealing behavior of
the double-wall TiO2 nanotubes was observed in the same TEM
system with a filament-type specimen heating holder.26 The sample
nanotubes were put on a Pt (70%)−Ir (30%) f