Preparation and photocathodic protection property of Ag2S-TiO2 composites

The Ag2S-TiO2 composites with good photocathodic protection performance for 304 stainless steel have been investigated here. The effects of different kinds of sulfur sources on this photocathodic protection property were also examined. TiO2 nanotubes were prepared by two-step electrochemical anodization. And Ag2S was loaded on the TiO2 nanotubes through a hydrothermal method. The morphology, crystal structure, elemental composition and light absorption capability of the samples were characterized by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), and ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS) analyses. The performances of cathodic protection were evaluated by the electro-chemical methods including open-circuit potential, photocurrent density and Tafel polarization curves. Results indicated that the Ag2S-TiO2 composites exhibited great enhancement of the light absorption and photo-electrochemical property under visible light illumination. The morphology and distribution of the samples have some effects on photocathodic protection properties of 304 stainless steel and the Ag2S-TiO2 composite with sodium sulfide as sulfur source showed the optimal performance.