AgInS ₂ and graphene co-sensitized TiO ₂ photoanodes for photocathodic protection of Q235 carbon steel under visible light

Abstract

AgInS₂ nanoparticle and graphene nanosheet co-sensitized anatase TiO₂ nanotube array films were fabricated by a combination of hydrothermal reaction and electrochemical anodization on titanium sheets. The results showed that the co-sensitization of AgInS₂ nanoparticles and graphene nanosheets extended the photoresponse of TiO₂ nanotubes into the visible-light region, and improved the photogenerated charge separation and transfer capability. The photocurrent density of the AgInS₂/graphene/TiO₂ composites (about 4.0 mA cm^-2) was 20 times that of bare TiO₂ (only 0.2 mA cm^-2) under visible-light illumination. The potential negative shift value of AgInS₂/graphene/TiO₂ composites was up to 0.68 V versus saturated calomel electrode. The AgInS₂/graphene/TiO₂ composites can provide Q235 carbon steel with highly efficient photocathodic protection under visible-light illumination.