Low-temperature hydrothermal formation of a net-like structured TiO2 film and its performance of photogenerated cathode protection

A net-like structured TiO2 film was obtained with a low-temperature hydrothermal process, followed by acid washing and calcination in air. The photoelectrochemical properties of the net-like structured TiO2 film coupled to 316L stainless steel (SS) for corrosion protection application in 3.5% NaCl solution were investigated and compared with the TiO2 nanotube (TN) array prepared by electrochemical anodization. The TiO2 films prepared by two different techniques were examined using SEM, Raman, XPS, photopotential variation with time, polarization measurements as well as EIS. It is found that the TiO2 films with different surface morphologies in a comparable film thickness range both offer a distinctly photogenerated cathode protection for 316L SS under the white light illumination. The results have been discussed in terms of the structure of TiO2 film and its performance of photogenerated cathode protection.