Online image monitoring and kinetics study on photocathodic protection of carbon steel using α-Fe2O3 photoanode

A highly efficient In2S3/Ag2S/TiO2NTAs photoelectrodes for photocathodic protection of Q235 carbon steel under visible light

A novel In₂S₃/Ag₂S/TiO₂nanotube arrays (NTAs) was successfully fabricated by successive ionic layer adsorption and reaction method and electrochemical anodic oxidation method, and served as photoanode for photocathodic protection application. The micromorphologies, optical absorption properties, crystalline structure and elemental valence states of the composites were performed by field emission scanning electron microscopy, high resolution transmission electron microscope, UV-vis diffuse reflectance absorption spectra, x-ray diffractometer and x-ray photoelectron spectroscopy, respectively. The photocathodic protection performances of In₂S₃/Ag₂S/TiO₂NTAs on the Q235 carbon steel (CS) were also studied. The In₂S₃/Ag₂S/TiO₂nanocomposites show better photoelectrocatalytic and photocathodic protection performance than pure TiO₂NTAs. The photocurrent density of In₂S₃(9)/Ag₂S(8)/TiO₂photoelectrode coupled with Q235 CS reach 211μA cm^-2, which is about 4.5 times higher than that of TiO₂NTAs. The photogenerated potential of Q235 CS coupled to In₂S₃(9)/Ag₂S(8)/TiO₂under illumination shows a negative shift to -0.92 V versus SCE. Results indicate that the co-sensitization of In₂S₃and Ag₂S could extend the light absorption of TiO₂to the visible light range and enhance its photoelectric conversion efficiency.