Computational molecular-level prediction of heterocyclic compound-metal surface interfacial behavior

It is difficult to comprehensively understand the interfacial mechanism (IM) of the adsorption of corrosion inhibitors (CIs) on metal surfaces solely through experiments and electronic structure parameters of isolated molecules. To better understand the molecular-level IM of CIs, a combination of atomistic simulations and first-principles calculations was used to obtain reliable information on the adsorption nature and intermolecular interactions during the actual interfacial behavior. The IM and property changes of two synthesized heterocyclic sustainable-green CIs, namely 4-{[(5-nitrofuran-2-yl)methylene]amino}-5-propyl-4H-1,2,4-triazole-3-thiol (NFPT and 4-{[(5-nitrofuran-2-yl)methylene]amino}-4H-1,2,4-triazole-3-thiol (NFT), were investigated on the Fe(110) surface using first-principles density functional theory (DFT) calculations and molecular dynamics (MD) simulations. The NFPT was preferentially adsorbed through a parallel configuration with a high interaction energy (-706.12 kJ·mol^-1) compared to NFT, owing to stronger chemical bonds via S, N, and O atoms with the Fe surface. Additionally, the adsorbed NFPT film effectively inhibited Fe surface corrosion owing to the small diffusion coefficient of corrosive particles in the presence of NFPT. Subsequently, the anti-corrosion performance of both CIs was validated through electrochemical methods, surface analysis, and adsorption isotherm models. The observations suggest that the combination of modern computational perspectives could efficiently design and select the best CIs before their laboratory synthesis.