Bi(2)Se(3) Sensitized TiO(2) Nanotube Films for Photogenerated Cathodic Protection of 304 Stainless Steel Under Visible Light

Titanium dioxide (TiO(2)) nanotube arrays coupled with a narrow gap semiconductor—bismuth selenide (Bi(2)Se(3))—exhibited remarkable enhancement in the photocathodic protection property for 304 stainless steel under visible light. Bi(2)Se(3)/TiO(2) nanocomposites were successfully synthesized using a simple two-step method, including an electrochemical anodization method for preparing pure TiO(2) and a chemical bath deposition method for synthesizing Bi(2)Se(3) nanoflowers. The morphology and structure of the composite films were studied by scanning electron microscopy, energy dispersion spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction. In addition, the influence of the Bi(2)Se(3) content on the photoelectrochemical and photocathodic protection properties of the composite films was also studied. The photocurrent density of the Bi(2)Se(3)/TiO(2) nanocomposites was significantly higher than that of pure TiO(2) under visible light. The sensitizer Bi(2)Se(3) enhanced the efficient separation of the photogenerated electron-hole pairs and the photocathodic protection properties of TiO(2). Under visible light illumination, Bi(2)Se(3)/TiO(2) nanocomposites synthesized by the chemical bath deposition method with Bi(3+) (0.5 mmol/L) exhibited the optimal photogenerated cathodic protection performance for 304 stainless steel.