GO-TiC 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 (TiC) 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% TiC or GO-TiC into epoxy zinc-rich coating (ZRC) effectively enhance the cathodic protection capability. Additionally, superior corrosion resistance was achieved by incorporation of GO-TiC into ZRC since GO-TiC 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, R value of ZRC/GO-TiC coating was 3.047 × 10 Ω·cm, 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-TiC coating exhibited lower speed of zinc particles oxidation and intact steel substrate. Hence, ZRC/GO-TiC coating exhibited the optimal corrosion resistance among the four kinds of coatings.