Study on the photocathodic protection of 304 stainless steel by Ag and In2S3 co-sensitized TiO2 composite

The photo-catalytic activity of TiO2 was greatly enhanced by co-sensitization with Ag and In2S3, and its application to protect 304 stainless steel from corrosion was reported. TiO2 nanotube arrays (TiO2 NTAs,) with large specific surface area and hollow nanostructures favored the immobilization of In2S3 and Ag. In2S3 as a narrow band gap semiconductor could broaden the light absorption range of TiO2. Surface plasmon resonance of Ag could accelerate the separation of photo-induced carriers generated from TiO2 and In2S3. The photo-induced potential drop of 304 stainless steel in NaCl solution measured 530 mV, and the photo-current density reached 45 µA/cm2 with visible light irradiation coupled with Ag and In2S3 co-sensitized TiO2 composite.