Fig. 1

SEM images of annealed TiO2 nanotubes: a unwashed TiO2 nanotubes, b washed TiO2 nanotubes, c low and d high magnification of cross-sectional view of washed TiO2 nanotubes
SEM images of annealed TiO2 nanotubes: a unwashed TiO2 nanotubes, b washed TiO2 nanotubes, c low and d high magnification of cross-sectional view of washed TiO2 nanotubes