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

Abstract A series of Sb 2 S 3 /Sb 2 O 3 /TiO 2 (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 Sb 2 S 3 promoted visible light harvesting. The p-n junction between p-type Sb 2 S 3 and n-type SO/T provides a driving force for the separation and transfer of carriers. Well crystallized Sb 2 O 3 rods offer a direct pathway for the carriers migration.