Synthesis of multi donating sites grafted on graphene oxide nanosheets: Anti-corrosion study for mild steel in 1 M HCl with DFT calculations

The functionalization of graphene oxide of Sulphate and Phosphate functionalized graphene oxide nanomaterials were investigated as corrosion inhibitors for mild steel in HCl media by employing weight loss, electrochemical, surface, and computational methods. The graphene oxide (GO) was synthesized from industrial waste material graphite. The GO and seven functionalized GO were characterized by the FTIR, SEM, and EDX techniques. The amide-functionalized GO (N-G) exhibited good corrosion inhibition compared to sulfate (S-G) and phosphate (P-G) functionalized GO. It was further observed that the addition of sulfate and/or phosphate functional groups along with amide (NSP-G), showed an improvement in layering structure and exhibited the highest corrosion inhibition (93.78%). FTIR, SEM, EDX, and Contact Angle studies supported the formation of an inhibitive film of NSP-G on the mild steel surface. Density functional theory (DFT) results reveal that the addition of three functional groups in GO enhanced its interaction sites with the mild steel surface. Molecular dynamics (MD) simulation results show the predominantly chemisorption mechanism of NSP-G on the mild steel surface.