Surface, Electrochemical, and Theoretical Investigation on Utilizing Olive Leaf Extract as Green Inhibitor for Copper Corrosion in Alkaline Environment

Olive leaf extract (OLE) was investigated to inhibit the copper corrosion in alkaline (0.5 M KOH solution), owing to the fact
that it is eco-friendly, nontoxic, and paltry substance. The inhibitory action of olive leaf extract was investigated utilizing
open circuit potential, cyclic voltammetry, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS),
scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), atomic force microscopy (AFM), and X-ray
photoelectron spectroscopy (XPS) techniques. The results revealed that olive leaf extract, inhibited the corrosion of Cu in the
investigated alkaline environment, yielding maximum inhibition efficiencies of 90.68%. The inhibitory efficiency value rises
with rising the amount of olive leaf extract and reduces by rising temperature. The inhibitory action was attributed to olive
leaf extract adsorbed on copper surface, which created a charge and mass movement barrier, shielding the metal from hostile
ions. OLE works fundamentally as a cathodic inhibitor, according to polarization curve parameters. EIS measurements have
shown that a more resistive passive film is formed on the Cu in the presence of OLE. The EIS data were fitted to theoretical
data according to a proposed model representing the electrode/electrolyte interface, and the equivalent circuit parameters were
calculated. The extracted molecules adsorb on the surface of metal according to Langmuir adsorption isotherm. According to
SEM/ EDX, AFM, and XPS investigations, the inhibitor can compose a preservative layer on the surface. Density functional
theory was furthermore utilized for examining the common components of olive leaf extract. The mechanism of adsorption
OLE on the surface of copper was studied utilizing Monte Carlo simulation. The theoretical outputs were discovered to
support the practical outcomes.