Synthesis of TiO2 nanotubes/nickel-gallium layered double hydroxide heterostructure for highly-efficient photocathodic anticorrosion of 304 stainless steel

The corrosion of 304 stainless steel (304SS) is a major global issue in the context of ships and marine engineering constructions. The photocathode anticorrosion system, composed of semiconductor material in the form of photoanode and 304SS in the form of cathode, is an effective method to solve 304SS corrosion of large components. Owing to the rapidly photoinduced charge-transfer at the semiconductor interface that supplies photogenerated electrons to the electrically connected 304SS and shifts the coupled potential to much more negative values, constructing a photoanode heterostructure material promotes charge separation and thus improves the photocathodic anticorrosion of 304SS. Herein, we fabricated TiO 2 nanotubes/nickel‑gallium layered double hydroxide (TiO 2 /NiGa-LDH) heterostructure material by the electrochemical anodization and hydrothermal method for highly-efficient photocathodic anticorrosion of 304SS. Owing to the modulated band structure and enhanced photogenerated carriers separation and transfer, TiO 2 /NiGa-LDH heterostructure material gave rise to largely reduced open circuit potential (OCP, −690 mV), which facilitated the transfer of electrons from the TiO 2 /NiGa-LDH heterostructure material to the 304SS to improve the photocathodic anticorrosion of 304SS, along with good stability after the OCP test for 72 h. This work provides a strategy for exploring LDH-based photoanodes materials toward highly-efficient photocathodic anticorrosion of 304SS.