The Effect Of Graphene On The Photocathode Protection Of Titania Films For304Stainless Steel

Since the photo-electrochemical anti-corrosion properties of TiO2film on the metal surface has been found, this photocathodic protection technology has attracted much attention during the past decade. Unlike traditional sacrifice anode method, TiO2in the process of cathode protection is lossless, workable in the solar energy, easy to prepare, environment-friendly and low costing, thus TiO2photocathode protection in the metal anti-corrosion has a broad application prospect.Graphene/TiO2films were prepared through the method of sol-gel and treated under different temperatures. XRD,SEM, TEM, and RM were used to characterize the phase, morphology and microstructure of these composite films. The results showed that composite films were composed of TiO2nanoparticles with the size of20nm and graphene sheets. The graphene sheets were wrapped closely by TiO2particles and intersperse into the TiO2films, giving rise to a three dimensional conductive-network.Photoelectric chemical testing system was used to study the influence of different process conditions on the photocathode protection performance of graphene/TiO2composite film. The research results show that the open circuit potential of composite thin film decreases with the increase of the amount of grapheme. When the content of graphene was more than0.5%, the open circuit potential of the sample keep stable at-0.6V. Photoelectric performance of composite films decreased with the increase of film thickness and the optimum number of the layer is one. The heating temperature has great influence on the performance of the film, and as the heating temperature is400℃, photoelectric performance of the sample is best. The size decrease of graphene contributes to the improvement of the photovoltaic performance of the composite thin film.Potentiodynamic polarization curve and ac impedance was used to study the photocathodic protection performance of the composite film for304stainless steel. Compact composite film can cut off the contact between the corrosive medium and304stainless steel in the dark, and thus the corrosion rate slows down. Under illumination,304stainless steel coated by graphene/TiO2composite film showed a stable photoelectric property. The potential of sample drops into cathodic protection area. Therefore, the304stainless steel can be protected effectively from corrosion by coating the grapheme/TiO2composite film.