Effect of Photoelectrochemical Activity of ZnO-Graphene Thin Film on the Corrosion of Carbon Steel and 304 Stainless Steel

In this research, the ZnOG hybrid thin film was produced via solgel method. The surface morphology, band gap and photoactive properties of the films were studied by means of SEM, UV-Vis and photoluminescence analysis. In addition, the ability of the thin film in photocathodic protection of carbon steel (CS) and 304 stainless steel in 3.5 wt.% NaCl and Na2S solutions under dark and UV illumination was investigated by polarization test as well as OCP and current measurements during coupling of steels with ZnOG photoanode. The mix band gap is reduced to the orders of 1.17 eV through hybridization of ZnO with graphene oxide. In both NaCl and Na2S solutions, the ZnOG thin film could effectively protect the SS304 in dark condition. Moreover, UV illumination improved the level of protection via photoinduced electrons. The ZnOG film slightly accelerates the corrosion of CS in dark condition in NaCl solution. Nevertheless, UV illumination leads to photocathodic protection of CS in mentioned environment. In Na2S solution, while coupling to ZnOG photoanode had not much effect on the surface electrochemical activity of CS, UV illumination caused photocathodic protection.