Assessment of corrosion inhibition performance of origanum compactum extract for mild steel in 1 M HCl: Weight loss, electrochemical, SEM/EDX, XPS, DFT and molecular dynamic simulation

© 2022 Elsevier B.V.In this study, plant ethanolic extract OCEE (Origanum Compactum Ethanolic Extract), a promising natural product with a cheap cost, was used as a green and sustainable mild steel corrosion inhibitor in a 1 M HCl solution. Chemical, electrochemical, surface analysis, and quantum chemical calculations were used to examine the inhibitory efficacy of OCEE on mild steel(MS) corrosion. Overall, the findings show that OCEE has excellent corrosion inhibitory characteristics, with a 90 % inhibitory efficacy at a dosage of 400 mg/L. The plots of Potentiodynamic Polarization (PDP) and Electrochemical Impedance Spectroscopy (EIS) demonstrate that the OCEE is a mixed type corrosion inhibitor and that the corrosion process is regulated by charge transfer, respectively. The Langmuir adsorption isotherm adequately characterized the adsorption of OCEE. OCEE has considerably higher activation thermodynamic characteristics than the blank. SEM/EDX surface examination shows that the OCEE may connect to the metal surface by producing a barrier layer, and XPS research confirms bonds between functional groups and the MS substrate. The electronic characteristics of the main OCEE compound were studied using the DFT technique (density functional theory), and the sites sensitive to electron sharing were discovered using the Fukui indices. Furthermore, MD (molecular dynamics) modelling was utilized to predict the spontaneous adsorption of this significant chemical on a mild steel surface.