Visible-light-driven photogenerated cathodic protection of stainless steel by liquid-phase-deposited TiO2 films

The liquid-phase-deposition (LPD) method was developed to prepare N–F-codoped TiO2 films that served as photoanodes for the cathodic protection of SUS304 stainless steel (304SS). The as-prepared LPD-TiO2 films were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Photoelectrochemical properties, such as open-circuit potential (OCP), photocurrent spectra, Tafel polarization curves and electrochemical impedance spectroscopy (EIS) of the LPD-TiO2 films, were also measured. The results indicate that the LPD-TiO2 films showed a visible-light response in the wavelength range of 600–750 nm. The photocurrent intensities in both the ultraviolet (UV)-light and visible-light regions were enhanced as the heat treatment (HT) temperature increased. However, the as-prepared LPD-TiO2 films exhibited the most negative photopotential under both visible-light and white-light illumination. In conclusion, the as-prepared LPD-TiO2 films would provide the most effective photogenerated cathodic protection of 304SS.

► The N–F-codoped TiO2 films were prepared on FTO substrate by liquid-phase-deposition.
► The TiO2 films showed a visible-light response in the wavelength of 600–750 nm.
► The TiO2 film exhibited an effective photogenerated cathodic protection for 304SS.