Self-assembly of ordered mesoporous TiO2 thin films as photoanodes for cathodic protection of stainless steel

Highlights: ► The ordered mesoporous TiO2 thin films were prepared on FTO substrates. ► The more effective photocathodic protection was observed for mesoporous TiO2 films. ► More negative photopotential was observed for 500 °C-calcined mesoporous TiO2 film. ► The larger photocurrent was observed for mesoporous TiO2 film calcined at 500 °C. - Abstract: In this paper, the ordered mesoporous TiO2 thin films that served as photoanodes for cathodic protection of SUS304 stainless steel (304SS) were prepared through the sol–gel and evaporation-induced self-assembly method. The as-prepared TiO2 thin films were calcined at 350 °C and 500 °C, and then characterized by scanning electron microscopy (SEM), the small-angle X-ray diffraction (SAXD) as well as the wide-angle X-ray powder diffraction (WAXD). Moreover, the photoelectrochemical properties of the mesoporous TiO2 thin films such as the open circuit potential (OCP), the photocurrent spectra as well as the Tafel polarization curves were also measured. The results showed that the more negative photopotential was observed for the mesoporous TiO2 films compared to the TiO2 films without mesoporous structures. Besides, the mesoporous TiO2 films calcined at 500 °C exhibited the more negative photopotential and larger photocurrent than that calcined at 350 °C. In conclusion, the mesoporous TiO2 films could provide the effective photogenerated cathodic protection for 304SS.