Density functional theory and molecular dynamics simulation study on corrosion inhibition performance of mild steel by mercapto-quinoline Schiff base corrosion inhibitor

•Performance of two mercapto-quinoline Schiff base as corrosion inhibitor was investigated theoretically.•Quantum chemical calculations and molecular dynamics simulation were performed.•Fukui indices have been used to analyze the local reactivity of the studied inhibitors.•Theoretical calculations agree well with the experimental findings.

Corrosion inhibition mechanism of two mercapto-quinoline Schiff bases, eg., 3-((phenylimino)methyl)quinoline-2-thiol (PMQ) and 3-((5-methylthiazol-2-ylimino)methyl) quinoline-2-thiol (MMQT) on mild steel surface is investigated by quantum chemical calculation and molecular dynamics simulation. Quantum chemical parameters such as EHOMO, ELUMO, energy gap (ΔE), dipolemoment (µ), electronegativity (χ), global hardness (η) and fraction of electron transfers from the inhibitor molecule to the metallic atom surface (ΔN) have been studied to investigate their relative corrosion inhibition performance. Parameters like local reactive sites of the present molecule have been analyzed through Fukui indices. Moreover, adsorption behavior of the inhibitor molecules on Fe (1 1 0) surface have been analyzed using molecular dynamics simulation. The binding strength of the concerned inhibitor molecules on mild steel surface follows the order MMQT>PMQ, which is in good agreement with the experimentally determined inhibition efficiencies. In view of the above, our approach will be helpful for quick prediction of a potential inhibitor from a lot of similar inhibitors and subsequently in their rational designed synthesis for corrosion inhibition application following a wet chemical synthetic route.

Graphical abstractCorrosion inhibition performances of two mercapto-quinoline Schiff base inhibitors have been performed and have correlated their experimentally observed inhibition efficiency by density functional theory and molecular dynamics simulation.Figure optionsDownload full-size imageDownload as PowerPoint slide