Visible Light Irradiation-Mediated Drug Elution Activity of Nitrogen-Doped TiO₂ Nanotubes

Figure 3

(a) XPS spectra of TiO₂ nanotubes and N-doped TiO₂ nanotubes. (b) High resolution XPS spectra of N 1s for TiO₂ nanotubes and N-doped TiO₂ nanotubes.

(a)

(b)