Bi2S3/rGO co-modified TiO2 nanotube photoanode for enhanced photoelectrochemical cathodic protection of stainless steel

Abstract A novel Bi2S3/reduced graphene oxide (rGO) co-modified TiO2 nanotube photoanode was fabricated on a Ti foil by anodization combined with cyclic voltammetric electrodeposition, and successive ionic layer adsorption and reaction. After modifying the TiO2 nanotube film with rGO sheets and Bi2S3 nanoparticles, the band gap of the Bi2S3/rGO/TiO2 composite film decreased, and its photoresponse was extended to the visible region. Under white light irradiation, the composite film in a 0.1 M Na2SO3 and 0.1 M Na2S solution exhibited 62.5 times higher photocurrent density than the TiO2 film. The composite film photoanode could make the potential of the coupled 403 stainless steel in a 0.5 M NaCl solution negatively shift by 490 mV, showing enhanced photoelectrochemical cathodic protection.