Inhibition efficiency and adsorption mechanism of 4-aminobenzoic acid for copper corrosion in nitric acid medium: a combined experimental and theoretical investigation

A combined experimental and theoretical study is presented to predict and analyze the inhibition efficiency and adsorption mechanism of 4-aminobenzoic acid molecule for copper corrosion in molar nitric acid. Experimentally, the investigation has been performed through polarization curves, electrochemical impedance spectroscopy (EIS), scanning electron microscopy, energy-dispersive X-ray spectrometry, and atomic force microscopy studies. Theoretically, the inhibition effect of 4-aminobenzoic acid on copper corrosion is evaluated from the DFT/B3LYP/6-311+G(d,p) calculated frontier molecular orbital (FMO) energies, global and local reactivity descriptors defined within the conceptual density functional theory (CDFT), electrostatic potential (ESP) mapping, and conformational analysis while the mechanism of adsorption onto the copper surface is studied from DFT-based molecular dynamics simulation. We obtained a good correlation between theoretical energy gap and the experimental corrosion inhibition efficiency for copper by amino acids. The experimental and theoretical findings show good agreement in both gas phase and water, establishing 4-aminobenzoic acid as a potent inhibitor of copper corrosion under acidic conditions.