Sb2S3/Sb2O3 modified TiO2 photoanode for photocathodic protection of 304 stainless steel under visible light

A series of Sb2S3/Sb2O3/TiO2 (SS/SO/T) composites with different reactant concentrations were synthesized via anodic oxidation and a one-pot hydrothermal method. The chemical compositions, morphologies, and optical absorption properties of prepared samples were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, energy disperse spectroscopy, elemental mapping and ultraviolet-visible diffuse reflectance spectroscopy. Photocathodic protection performances of these samples were studied using time-dependent open circuit potential, time-dependent photoinduced current density, and photoinduced volt-ampere characteristic. The SS/SO/T composite with a 48 mmol/L antimony source exhibited optimal performance for 304 stainless steel (304SS). This excellent performance origins from the synergistic effect of the ternary system. The narrow band gap Sb2S3 promoted visible light harvesting. The p-n junction between p-type Sb2S3 and n-type SO/T provides a driving force for the separation and transfer of carriers. Well crystallized Sb2O3 rods offer a direct pathway for the carriers migration.