GO-Ti3C2 two-dimensional heterojunction nanomaterial for anticorrosion enhancement of epoxy zinc-rich coatings

MXenes are a unique family of two-dimensional (2D) transition metal carbides and/or nitrides, which have been proven useful for energy storage, water purification, and biomedical applications. Herein, a kind of heterojunction structure was designed by grafting highly conductive MXene (Ti3C2) on the graphene oxide (GO) nanosheets, which was confirmed by Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectronic spectroscopy (XPS) and Raman results. Open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and salt spray measurements corroborated that inclusion of 0.5 wt% Ti3C2 or GO-Ti3C2 into epoxy zinc-rich coating (ZRC) effectively enhance the cathodic protection capability. Additionally, superior corrosion resistance was achieved by incorporation of GO-Ti3C2 into ZRC since GO-Ti3C2 in the coating improved the utilization rate of zinc particles and GO provided barrier protection for inhibiting the diffusion of corrosive agents. At the end of immersion, Rc value of ZRC/GO-Ti3C2 coating was 3.047 & times; 104 omega & sdot;cm2, which was one order of magnitude higher than that of ZRC coating. Scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) measurements demonstrated that ZRC/GO-Ti3C2 coating exhibited lower speed of zinc particles oxidation and intact steel substrate. Hence, ZRC/GO-Ti3C2 coating exhibited the optimal corrosion resistance among the four kinds of coatings.