Coating of Al-X (X = Mg, Ga, Si) Alloys Nanosurface with Organic Corrosion Inhibitors Using TD-DFT Approach: Intra-Atomic and Interatomic Investigation through Langmuir Adsorption Study

Abstract

The adsorption analysis of some organic inhibitors consisting of benzotriazole, 8-hydroxyquinoline, 2-mercaptobenzothiazole onto aluminum alloy surface based on optimized coordination of binding on the Al-X (Mg, Ga, Si) surface has been accomplished. In this work, the ONIOM approach has been performed with a three-layered level of high level of DFT method using EPR-III, 6-31+G(d,p) and LANL2DZ basis sets by the physico-chemical software of Gaussian 16 revision C.01 program, a medium semi-active part that includes important electronic contributions, and a low level part that has been handled using MM2 force field approaches. The physico-chemical properties of adsorption -surface complexes are one of the principal parameters for determining and choosing the Langmuir adsorption through IR, NMR, UV-Vis, HOMO/LUMO and charge distribution results. Comparing to Delta G(ads)degrees amounts approved a good agreement among computed results, as well as the correctness of the selected isotherm for the adsorption process of benzotriazole -> Al-Mg, benzotriazole -> Al-Ga, benzotriazole -> Al-Si, 8-hydroxyquinoline -> Al-Mg, 8-hydroxyquinoline -> Al-Ga, 8-hydroxyquinoline -> Al-Si, 2-mercaptobenzothiazole, 2-mercaptobenzothiazole -> Al-Mg, 2-mercaptobenzothiazole -> Al-Ga, and 2-mercaptobenzothiazole -> Al-Si. Nuclear magnetic resonance has certainly has focused on the aluminum shielding in the intra-atomic interaction with magnesium, gallium and silicon and simultaneously interatomic interaction with other atoms in organic inhibitors through variety of high, medium and low layers of ONIOM method. Al-Si with highest fluctuation in the shielding tensors of NMR spectrum generated by intra-atomic interaction leads us to the most influence in the neighbor atoms generated by interatomic reaction. Moreover, based on the computed amounts of UV-Vis spectra for benzotriazole, 8-hydroxyquinoline and 2-mercaptobenzothiazole adsorb on the Al(111)-alloy surface, there are maximum adsorption bands between 200-280 nm for benzotriazole, 225-350 nm for 8-hydroxyquinoline and 210-280 nm for 2-mercaptobenzothiazole, respectively; and maximum adsorption bands for benzotriazole, 8-hydroxyquinoline, and 2-mercaptobenzothiazole has observed around 230, 300, and 240 nm, respectively.