Photogenerated cathodic protection of flower-like, nanostructured, N-doped TiO2 film on stainless steel

Flower-like, nanostructured, N-doped TiO2 (N-TiO2) films were fabricated using a low-temperature hydrothermal method. The morphology, crystalline phase, and composition of these flower-like nanostructured films were characterized systematically by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and UV–vis spectroscopy. The photoelectrochemical properties of N-TiO2 films in 0.5 M NaCl solution were evaluated under illumination and in the dark through electrochemical measurements. Flower-like nanostructured TiO2 films exhibited a drastically enhanced photocurrent in the UV light region and a notable absorption in the visible light region (600–700 nm). The negative shifts of the electrode potentials of 316L stainless steel coupled with N-doped TiO2 photoanodes are 470 and 180 mV under UV and visible light irradiation, respectively. The flower-like, nanostructured, N-doped TiO2 films were able to function effectively as photogenerated cathodic protection for metals under UV and visible light illumination. Such photogenerated cathodic protection could last a period of 5.5 h even in darkness.