Preparation of SnInS/TiO Nanotube Photoanode and Its Photocathodic Protection for Q235 Carbon Steel Under Visible Light.

TiO is an attractive semiconductor suitable for photocathodic protection, but its weak absorption of visible light and low quantum yield limit its usage. Here, a new heterostructured SnInS nanosheet/TiO nanotube photoanode was prepared and its photocathodic protection performance was analyzed. SnInS nanosheets were uniformly deposited on the surface of the TiO nanotube via a solvothermal treatment. The SnInS/TiO composite exhibited better photocathodic protection performance compared with pure TiO nanotubes, owing to its good visible-light response and photogenerated carrier separation efficiency. Moreover, the composite exhibited a maximum photocurrent density of 100 μA cm for a 6 h solvothermal reaction under visible light irradiation. The negative shift of the photoinduced potential of Q235 carbon steel connected to the composite could reach 0.45 V versus SCE. Therefore, the SnInS/TiO composite can offer efficient photocathodic protection for Q235 carbon steel against corrosion in 3.5 wt% NaCl solution. This work provides a new approach for the development of high-efficient photoanode materials for the photocathodic protection of metals.