Improved photocathodic protection and S-scheme mechanism of graphene and ZnFe2O4 decorated TiO2 nanosheets with {001} facet exposed

Photo-generated corrosion protection has received wide attention recently for non-sacrifice. A TiO2 nanosheets/ graphene/ZnFe2O4 hybrid was constructed by hydrothermal and solvothermal deposition method in this work. Sheet-like anatase crystallites with highly reactive {001} facets exposed was confirmed by XRD and TEM ananlysis. The hybrid showed novel photoelectrochemical performance and improved photocathodic protection of the connected 304 stainless steel. An S-scheme mechanism of electron migration was proposed and confirmed by Mott-Schottky and EIS analysis. The internal electric field formed in the hybrids accelerates electron migration with graphene acts as the transmission medium. The S-scheme system locates photo-excited electrons in a high energy level that boosts electron transfer from the hybrid semiconductor to the coupled 304 SS, leading to enhanced photoelectrochemical performance and improved photogenerated cathodic protection.