Figure 1

Variation of the OCP. At (a) for the 0.2% Ce-TiO₂ coatings with different layers under illumination, (b) for the three-layer Ce-TiO₂ coatings with different cerium ion contents under illumination, and (c) Tafel curves of pure TiO₂ coating and 1.2% Ce-TiO₂ coating under illumination and in the dark. Line a: 1.2% Ce-TiO₂ in the dark, line b: pure TiO₂ in the dark; line c: 1.2% Ce-TiO₂ under illumination; line d: pure TiO₂ under illumination.