Photoelectrochemical Performance of SnS2 Sensitized TiO2 Nanotube for Protection of 304 Stainless Steel

Abstract

SnS2-sensitized TiO2 nanotubes were fabricated via anodic oxidation and a successive ionic layer adsorption and reaction process. The prepared SnS2/TiO2 composites were used as photoanodes, and the corresponding photocathodic protection effect on 304 stainless steel was studied. The effect of the number of adsorbed SnS2 molecules on the photocatalytic protection conferred by the SnS2/TiO2 composites was also analyzed. The morphology and composition of the samples were analyzed by scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The optical absorption properties of the samples were analyzed by ultraviolet-visible diffuse reflectance spectroscopy. The electrochemical properties of the SnS2/TiO2 composites were characterized in terms of their open circuit potential, the photocurrent density, the electrochemical impedance spectrum and the current-voltage curve and used to analyze the photocatalytic protection effect. The results show that the SnS2/TiO2 composite exhibits higher visible light absorption and offers more photocathodic protection than pure TiO2 nanotubes. Using SnS2/TiO2(6C) as a photoanode reduces the potential of 304 stainless steel to −730 mV.