Experimental and theoretical studies on the inhibitory potential of <i>Lippia javanica</i> leaf extract for aluminium corrosion in 1M HCl medium

Electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), and gravimetric analysis techniques were used to evaluate the ability of Lippia javanica leaf extract inhibit aluminium (Al) corrosion in 1 M HCl solution. The formation protective film was confirmed using Ultraviolet-visible (UV–Vis), Fourier transform-infrared (FTIR) contact angle studies. According EIS, presence L. acidic solution decreased current density (icorr) double-layer capacitance (Cdl) due a adsorption layer on Al surface. PDP curves revealed anodic passivation substrate, well-known property highly entropic alloy like Al. Gravimetric results showed that maximum efficacy 91.89% when optimal concentration 800 ppm. increased 123° ALJPE, indicating hydrophobic nature surface film. FTIR spectra involvement C=O, C=C, O–H, =C–O–C, S=O, C–H during process, leading ALJPE–Al3+ complexes. It discovered mechanism follows Langmuir isotherm description process. Using functional theory (DFT), different dsorption positions studied, finding verbascoside preferentially binds Al(111) via phenylethanoid group, with oxygen atom close surface, binding energy 114.620 kcal/mol.