The long-term photoelectrochemical cathodic protection by Co(OH)(2)-surface modified TiO2 of anatase nanotubes and rutile type, prepared by anodic oxidation has been studied in aqueous 3.5 wt% NaCl solution. Electrochemical measurements have been used to evaluate the photoelectrochemical protective properties of both Co(OH)(2)-modified TiO2 coupled with 304 stainless steel in 3.5 wt% NaCl solution under illumination and in the dark. Morphologies, crystal structures, surface compositions, and light response range of both Co(OH)(2)-surface modified TiO2 films before and after immersion were characterized, respectively, by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-Vis spectrophotometry. The results show that the photogenerated electrode potential of both types of TiO2 films modified with Co(OH)(2) is more negative affording protection of 304 stainless steel than that of the non-modified TiO2 under illumination. These TiO2 films provide a long period (12 h) of protection. The anatase-TiO2 nanotube film always shows a better protection performance than rutile-TiO2 film. (C) The Author(s) 2018. Published by ECS.