Enhanced photocathodic protection performance of Ag/graphene/TiO₂composite for 304SS under visible light

Abstract

Ag and graphene co-sensitized TiO₂ composites were successfully fabricated and used as photoanodes for photogenerated cathodic protection of 304 stainless steel (304SS) under visible light. Graphene films was firstly deposited onto the TiO₂ nanotube (NT) films via cyclic voltammetric electrodeposition. Ag/graphene/TiO₂ films were then fabricated via dipping and photoreduction method. The morphology, composition and optical response of the Ag/graphene/TiO₂ NT composites were characterized by scanning electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, UV-vis diffusion reflectance spectroscopy, respectively. The photocathodic protection performance of the Ag/graphene/TiO₂ composites were systematically studied through open-circuit potential and potentiodynamic polarization measurements in 3.5 wt% NaCl solution under visible light (λ > 400 nm). The composites exhibited enhanced photogenerated cathodic protection performance for 304SS under visible light irradiation compared to pure TiO₂. Graphene and Ag have a synergistic effect on the enhancement of photocathodic protection performance of TiO₂. The composites prepared with 30-cycle graphene film and 15 mM AgNO₃ solution showed the optimal corrosion protection performance.