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

Abstract

SnS 2 -sensitized TiO 2 nanotubes were fabricated via anodic oxidation and a successive ionic layer adsorption and reaction process. The prepared SnS 2 /TiO 2 composites were used as photoanodes, and the corresponding photocathodic protection effect on 304 stainless steel was studied. The effect of the number of adsorbed SnS 2 molecules on the photocatalytic protection conferred by the SnS 2 /TiO 2 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 SnS 2 /TiO 2 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 SnS 2 /TiO 2 composite exhibits higher visible light absorption and offers more photocathodic protection than pure TiO 2 nanotubes. Using SnS 2 /TiO 2 (6C) as a photoanode reduces the potential of 304 stainless steel to −730 mV.