Novel organoselenium-based N-mealanilic acids as efficacious corrosion inhibitors for 6061 aluminum alloy in molar HCl: In-silico modeling, electrochemical, and surface morphology studies

Abstract

BackgroundDespite the exciting activities of organoselenium compounds, their anticorrosive efficiency was scarcely valued in the literature. Herein, two novel organoselenium-based N-mealanilic acids Namely: (E)-4-((2-(methoxycarbonyl)-4-selenocyanatophenyl)amino)-4-oxobut-2-enoic acid (NMSeCN) and (2E,2′E)-4,4′-((diselanediylbis(2-(methoxycarbonyl)-4,1-phenylene))bis(azanediyl))bis(4-oxobut-2-enoic acid) (NMSe2) were synthesized. MethodsTheir corrosion inhibition was examined towards 6061 aluminum alloy in 1.0 mol L − 1 HCl utilizing potentiodynamic polarization (PP), impedance spectroscopy (EIS), Energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), Density Functional Theory (DFT), and Monte Carlo (MC) simulations. FindingsElectrochemical findings revealed the inhibition efficiency enhance in the order: NMSe2 > NMSeCN with extreme protection efficacy (98.2%) obtained at 6.4 × 10−3 mol L − 1 of NMSe2. Both cathodic (βc) and anodic (βa) Tafel constants were appreciably influenced by the insertion of the additives into the corrosion solution suggesting a mixed type reduces both anodic and cathodic reaction. The adsorption of the NMSeCN and NMSe2 on the aluminum surface is spontaneous and followed the isotherm of Langmuir. The annealing adsorption simulations showed a nearly flat configuration of NMSeCN and NMSe2 molecules on Al (1 1 1) surface which endorses optimal surface coverage. DFT calculations showed that the donation ability of NMSe2 inhibitor to the Al alloy interface is higher than the NMSeCN which in turn was in good agreement with the electrochemical experiments. According to the experimental and theoretical outcomes, the inhibition mechanism was suggested.