Fabrication of Ni3S2/TiO2 photoanode material for 304 stainless steel photocathodic protection under visible light

Abstract TiO2 is a promising photoanode material for cathodic protection. However, the photogenerated electron efficiency of TiO2 under visible light is rather low because of its poor absorption of visible light and the instability of its electron-hole pairs, which limit its application in the field of photocathodic protection. Here, Ni3S2 was used to modify TiO2 to enhance its photocathodic protection effect. Ni3S2/TiO2 composites (NSTs) were successfully synthesized by the hydrothermal method. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were used to characterize morphology, crystal structure, and elemental composition and its valence state. The light absorption properties of the samples were characterized by UV–visible diffuse reflectance spectroscopy (DRS). In addition, the photocathodic protection effects of TiO2 and NSTs were evaluated by measurements of the open-circuit potential (OCP) and photocurrent density with time (j-t). The results showed that the NSTs provided better photocathodic protection than pure TiO2 to 304 stainless steel (304ss).