A novel nitrogen- and sulfur-grafted reduced graphene oxide doped with zinc cations for corrosion mitigation of mild steel

Abstract

Grafting of N- and S- compounds on the reduced graphene oxide results in an increase in corrosion protection properties. In this work, for the first time, simultaneous grafting of both N- and S- atoms on the graphene oxide was accomplished using a natural source, Allium Sativum extract (ALS), which is rich in nitrogen and sulfur functionalities. The synthesis of sulfur- and nitrogen-grafted reduced graphene oxide (FrGO) was conducted using the hydrothermal route, and zinc cations were loaded on the FrGO consecutively. X-ray photoelectron microscopy (XPS) substantiated the successful grafting of ALS on the graphene oxide surface. The obtained products were characterized using diverse means, including Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Raman, UV–Vis, contact angle measurement, and thermogravimetric analysis (TGA). The morphology of the samples was determined using field emission scanning electron microscopy (FE-SEM). The incorporation of S, N, and Zn atoms was ascertained using dispersive X-ray spectroscopy (EDS) analysis. The synthesized substances, including graphene oxide (GO), functionalized/reduced graphene oxide (FrGO), and Zn loaded FrGO (Zn@FrGO), were used to prepare anti-corrosion epoxy coatings. The formulated coatings were evaluated using FE-SEM, electrochemical impedance spectroscopy (EIS), and salt spray test (SST). A considerable impact of the Zn@FrGO on the active corrosion protection properties was observed, which makes it a good candidate to be used as a replacement for toxic inhibitive substances.