Photocatalysis and Photoelectrochemical Properties of Tungsten Trioxide Nanostructured Films

Figure 3

FESEM images of anodic WO₃ nanostructures obtained in 1 M Na₂SO₄ electrolyte containing 0.7 wt% NH₄F for different anodization times at 40 V: (a) 15 min, (b) 30 min, and (c) 60 min. Insets show the cross-sectional view of anodic oxide layers.

(a)

(b)

(c)